WO2022149454A1 - Negative electrode active material for nonaqueous electrolyte power storage elements, negative electrode for nonaqueous electrolyte power storage elements, nonaqueous electrolyte power storage element, and power storage device - Google Patents

Negative electrode active material for nonaqueous electrolyte power storage elements, negative electrode for nonaqueous electrolyte power storage elements, nonaqueous electrolyte power storage element, and power storage device Download PDF

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WO2022149454A1
WO2022149454A1 PCT/JP2021/047046 JP2021047046W WO2022149454A1 WO 2022149454 A1 WO2022149454 A1 WO 2022149454A1 JP 2021047046 W JP2021047046 W JP 2021047046W WO 2022149454 A1 WO2022149454 A1 WO 2022149454A1
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negative electrode
power storage
aqueous electrolyte
electrode active
storage element
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French (fr)
Japanese (ja)
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英佑 澤田
拓実 三宅
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株式会社Ｇｓユアサ
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/05—Preparation or purification of carbon not covered by groups C01B32/15, C01B32/20, C01B32/25, C01B32/30
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/15—Nano-sized carbon materials
    • C01B32/158—Carbon nanotubes
    • C01B32/168—After-treatment
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/04—Hybrid capacitors
    • H01G11/06—Hybrid capacitors with one of the electrodes allowing ions to be reversibly doped thereinto, e.g. lithium ion capacitors [LIC]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/22—Electrodes
    • H01G11/30—Electrodes characterised by their material
    • H01G11/32—Carbon-based
    • H01G11/38—Carbon pastes or blends; Binders or additives therein
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/22—Electrodes
    • H01G11/30—Electrodes characterised by their material
    • H01G11/32—Carbon-based
    • H01G11/42—Powders or particles, e.g. composition thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/66—Current collectors
    • H01G11/68—Current collectors characterised by their material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0569—Liquid materials characterised by the solvents
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials

Definitions

  • the present invention relates to a negative electrode active material for a non-aqueous electrolyte power storage element, a negative electrode for a non-aqueous electrolyte power storage element, a non-aqueous electrolyte power storage element, and a power storage device.
  • Non-aqueous electrolyte secondary batteries represented by lithium-ion non-aqueous electrolyte secondary batteries are widely used in personal computers, electronic devices such as communication terminals, automobiles, etc. due to their high energy density.
  • the non-aqueous electrolyte secondary battery generally includes an electrode body having a pair of electrodes electrically separated by a separator, and a non-aqueous electrolyte interposed between the electrodes, and transfers ions between the two electrodes. It is configured to charge and discharge by doing.
  • capacitors such as lithium ion capacitors and electric double layer capacitors are also widely used as non-aqueous electrolyte storage elements other than non-aqueous electrolyte secondary batteries.
  • Copper foil is widely used as the negative electrode base material of such a non-aqueous electrolyte power storage element.
  • a negative electrode base material made of aluminum foil is preferable.
  • a negative electrode base material in which the surface of an aluminum foil is coated with carbon has been proposed (see Patent Document 1).
  • the non-aqueous electrolyte power storage element is required to have a quick charge acceptance performance depending on the application.
  • a lithium-aluminum alloying reaction is likely to occur, so it is necessary to operate the negative electrode at a noble potential of about 0.35 V (vs. Li / Li + ) or higher. be.
  • vs. Li / Li + vs. Li / Li +
  • the charge / discharge capacity of graphite and non-graphitizable carbon (hard carbon) is 80 mAhg -1 or less when the charge termination potential is 0.4 V (vs. Li / Li + ), and the capacity per mass.
  • Lithium titanate which is used as a negative electrode active material to which an aluminum foil can be applied as a negative electrode base material, has an operating potential of about 1.5 V (vs. Li / Li + ) and 0.35 V (vs. Li / Li). Although it is significantly more noble than + ), it has problems such as low capacity, high potential, and high cost. Therefore, there is a demand for the development of a high-capacity negative electrode active material that operates in a relatively noble potential region in which an aluminum foil can be used as a negative electrode base material.
  • the present invention has been made based on the above circumstances, and enhances the discharge capacity per mass and the Coulomb efficiency in a relatively noble potential region of about 0.35 V (vs. Li / Li + ) or more. It is an object of the present invention to provide a negative electrode active material for a non-aqueous electrolyte power storage element capable of producing a negative electrode.
  • the negative electrode active material for a non-aqueous electrolyte power storage element contains boron and contains a carbon material having a layered crystal structure, and is a boron-carbon bond contained in the carbon material obtained by the following formula 1.
  • the content of boron forming is 1400 cm -1 or more and 1550 cm with respect to the maximum intensity IG in the range of 1500 cm -1 or more and 1700 cm -1 or less in the spectrum of the above carbon material by Raman spectroscopy.
  • the ratio IV / IG of the minimum intensity IV in the range of -1 or less is 0.5 or more.
  • X A ⁇ D / E ⁇ ⁇ ⁇ 1
  • X is the content (% by mass) of boron forming a boron-carbon bond
  • A is the content of total boron contained in the carbon material obtained by high frequency induced bond plasma emission spectroscopy (%).
  • Mass%) D is the integrated intensity of B1s in the range of 186 eV or more and 188 eV or less when the peak position of C1s showing the maximum intensity in the range of 272 eV or more and 300 eV or less is 284.8 eV in the spectrum by X-ray photoelectron spectroscopy.
  • E are the integrated intensities of B1s in the range of 186 eV or more and 196 eV or less in the spectrum obtained by the X-ray photoelectron spectroscopy.
  • Another aspect of the present invention is a negative electrode for a non-aqueous electrolyte power storage element containing a negative electrode active material for a non-aqueous electrolyte power storage element according to the above aspect of the present invention.
  • Another aspect of the present invention is the non-aqueous electrolyte power storage element provided with the negative electrode for the non-aqueous electrolyte power storage element according to the above aspect of the present invention.
  • Another aspect of the present invention is a power storage device provided with two or more non-aqueous electrolyte power storage elements and one or more non-water electrolyte power storage elements according to the above aspect of the present invention.
  • a negative electrode active material for a non-aqueous electrolyte power storage element capable of increasing the discharge capacity per mass and the Coulomb efficiency in a relatively noble potential region of about 0.35 V (vs. Li / Li + ) or more is provided. Can be provided.
  • FIG. 1 is a perspective perspective view showing an embodiment of a non-aqueous electrolyte power storage device.
  • FIG. 2 is a schematic view showing an embodiment of a power storage device in which a plurality of non-aqueous electrolyte power storage elements are assembled.
  • the negative electrode active material for a non-aqueous electrolyte power storage device contains a carbon material containing boron and having a layered crystal structure, and has the following formula 1
  • the content of boron forming a boron-carbon bond contained in the carbon material obtained in 1 above is 0.6% by mass or more, and the range of 1500 cm -1 or more and 1700 cm -1 or less in the spectrum of the carbon material by Raman spectroscopy.
  • the ratio of the minimum intensity IV to the maximum intensity IG in the range of 1400 cm -1 or more and 1550 cm -1 or less is 0.5 or more.
  • X A ⁇ D / E ⁇ ⁇ ⁇ 1
  • X is the content (% by mass) of boron forming a boron-carbon bond
  • A is the content of total boron contained in the carbon material obtained by high frequency induced bond plasma emission spectroscopy (%).
  • Mass%) D is the integrated intensity of B1s in the range of 186 eV or more and 188 eV or less when the peak position of C1s showing the maximum intensity in the range of 272 eV or more and 300 eV or less is 284.8 eV in the spectrum by X-ray photoelectron spectroscopy.
  • E are the integrated intensities of B1s in the range of 186 eV or more and 196 eV or less in the spectrum obtained by the X-ray photoelectron spectroscopy.
  • the negative electrode active material can increase the discharge capacity per mass and the Coulomb efficiency in a relatively noble potential region of about 0.35 V (vs. Li / Li + ) or more. The reason for this is not clear, but the following reasons are presumed. In the prior art, it has been reported from the results of first-principles calculations that the carbon material BC 3 containing B can occlude more lithium ions than graphite (J. Phys. Chem. Lett. 2013, 4, 10, 1737-1742.).
  • the negative electrode active material having a boron-carbon bond-forming boron content of 0.6% by mass or more contained in the carbon material has a high content of boron doped by replacing carbon in the graphene layer. Therefore, the discharge capacity per mass and the Coulomb efficiency in a relatively noble potential region are improved. Further, it is presumed that the carbon material doped with boron in the graphene layer has a low graphitization degree and a high ratio IV / IG . Therefore, the negative electrode active material in which boron is doped in the graphene layer and the ratio IV / IG is 0.5 or more causes a decrease in defects in the graphene layer and an increase in the reversible capacity of the negative electrode active material.
  • the negative electrode active material can increase the discharge capacity per mass and the Coulomb efficiency in a relatively noble potential region of about 0.35 V (vs. Li / Li + ) or more.
  • the amount of oxygen desorbed at an atmospheric temperature of more than 800 ° C. is preferably 2.45% by mass or less with respect to the carbon material.
  • the carbon material contains an oxygen-containing functional group, the capacity increases, but the charge / discharge hysteresis becomes large, the irreversible capacity increases, and the capacity retention rate tends to decrease.
  • CVD chemical vapor deposition
  • the synthesized carbon material having a boron-carbon bond has many edge surfaces exposed. However, there are many defects in the crystal structure. Therefore, the synthesized carbon material is easily oxidized in the air, and an oxygen-containing functional group is formed on the surface.
  • the carbon material having a boron-carbon bond has a large charge / discharge hysteresis. Therefore, in a carbon material having a boron-carbon bond, it is presumed that the smaller the content of oxygen desorbed at more than 800 ° C., the smaller the content of oxygen-containing functional groups, and the smaller the charge / discharge hysteresis. Therefore, in the negative electrode active material, the amount of oxygen desorbed at an atmospheric temperature of more than 800 ° C. is 2.45% by mass or less with respect to the carbon material, so that the charge / discharge hysteresis can be reduced. In addition, the Coulomb efficiency can be improved by reducing the charge / discharge hysteresis.
  • the charge / discharge hysteresis indicates the difference between the average closed circuit potential during charging and the average closed circuit potential during discharging.
  • the average particle size in the particle size distribution of the carbon material is more than 3.56 ⁇ m and less than 7.68 ⁇ m.
  • the negative electrode active material can particularly increase the discharge capacity per mass in a relatively noble potential region.
  • the full width at half maximum of the (002) plane diffraction peak by the manual method in the powder X-ray diffraction pattern using CuK ⁇ as a radiation source is more than 1.77 °. Since the full width at half maximum of the (002) plane diffraction peak of the negative electrode active material is more than 1.77, the discharge capacity in a relatively noble potential region can be maintained in a good range, and the discharge capacity is relatively low. Can show a good discharge potential.
  • the negative electrode for a non-aqueous electrolyte power storage element (hereinafter, also simply referred to as “negative electrode”) according to one aspect of the present invention contains the negative electrode active material. Since the negative electrode contains the negative electrode active material, it is possible to increase the discharge capacity per mass and the Coulomb efficiency in a relatively noble potential region of about 0.35 V (vs. Li / Li + ) or more.
  • the negative electrode further contains carbon nanotubes.
  • the coulombic efficiency at the time of overcharging can be improved.
  • a carbon material having a boron-carbon bond tends to be isolated from the electron conduction path of the negative electrode active material because the volume of the carbon material expands and contracts with charge and discharge.
  • the negative electrode contains carbon nanotubes, it is considered that the carbon nanotubes maintain the network of electron conduction paths in the negative electrode active material layer and reduce the amount of isolated negative electrode active material. Therefore, the negative electrode further contains carbon nanotubes, so that the coulombic efficiency at the time of overcharging can be improved.
  • the working potential of the negative electrode can be 0.01 V (vs. Li / Li + ) or more, and when the working potential of the negative electrode is 0.35 V (vs. Li / Li + ) or more, the non-water It is preferable that the negative electrode for the electrolyte storage element further has a negative electrode base material made of pure aluminum or an aluminum alloy.
  • the negative electrode for the non-aqueous electrolyte power storage element further has a negative electrode base material made of pure aluminum or an aluminum alloy, so that cost reduction and weight reduction can be achieved.
  • the non-aqueous electrolyte power storage element includes the negative electrode. Since the non-aqueous electrolyte power storage element includes the negative electrode, it is possible to increase the discharge capacity per mass and the Coulomb efficiency in a relatively noble potential region of about 0.35 V (vs. Li / Li + ) or more.
  • the non-aqueous electrolyte power storage element preferably has a negative electrode potential of 0.35 V (vs. Li / Li + ) or more at the end-of-charge voltage during normal use.
  • the non-aqueous electrolyte power storage element can be charged so that the negative electrode potential is 0.35 V (vs. Li / Li + ) or more during normal use, thereby suppressing the precipitation of metallic lithium in the negative electrode in the form of dendrite. Therefore, quick charging is possible. Further, when the negative electrode has a negative electrode base material made of pure aluminum or an aluminum alloy, deterioration of the power storage element performance due to the lithium-aluminum alloying reaction can be suppressed.
  • the normal use is a case where the non-aqueous electrolyte storage element is used by adopting the charge / discharge conditions recommended or specified for the non-aqueous electrolyte storage element, and the non-aqueous electrolyte power storage element is used.
  • a charger for this purpose it means a case where the charger is applied to use the non-aqueous electrolyte power storage element.
  • the carbon material acts as a negative electrode active material, and ions involved in the charge / discharge reaction from the non-aqueous electrolyte to the negative electrode active material (lithium ions in the case of a lithium ion non-aqueous electrolyte secondary battery).
  • the reduction reaction in which the water is stored is called “charging”
  • the oxidation reaction in which the ions involved in the charge / discharge reaction are released from the negative electrode active material to the non-aqueous electrolyte is called "discharge”.
  • the non-aqueous electrolyte storage element preferably includes a non-aqueous electrolytic solution containing propylene carbonate as a non-aqueous solvent.
  • the non-aqueous electrolyte power storage element contains propylene carbonate as a non-aqueous solvent, so that it can exhibit an excellent high rate charge electricity amount ratio.
  • the non-aqueous electrolyte storage element preferably includes a non-aqueous electrolytic solution containing diethyl carbonate as a non-aqueous solvent.
  • the non-aqueous electrolyte power storage element contains diethyl carbonate as a non-aqueous solvent, so that it can exhibit an excellent high rate charge electricity quantity ratio.
  • Another aspect of the present invention is a power storage device provided with two or more non-aqueous electrolyte power storage elements and one or more non-water electrolyte power storage elements according to the above aspect of the present invention. Since the power storage device includes one or more non-aqueous electrolyte power storage elements, it is possible to increase the discharge capacity per mass and the Coulomb efficiency in a relatively noble potential region. It was
  • Configuration of negative electrode active material for non-aqueous electrolyte power storage element method for manufacturing negative electrode active material for non-aqueous electrolyte power storage element, configuration of negative electrode for non-aqueous electrolyte power storage element, configuration of non-aqueous electrolyte power storage element according to one embodiment of the present invention.
  • the configuration of the non-aqueous electrolyte power storage device, the method for manufacturing the non-water electrolyte power storage element, and other embodiments will be described in detail.
  • the name of each component (each component) used in each embodiment may be different from the name of each component (each component) used in the background technique.
  • the negative electrode active material for a non-aqueous electrolyte power storage element contains boron and contains a carbon material having a layered crystal structure.
  • the negative electrode active material contains a carbon material having a layered crystal structure.
  • a carbon material as the negative electrode active material, the energy density of the non-aqueous electrolyte power storage element can be increased.
  • the carbon material having a layered crystal structure include graphite, non-graphitizable carbon (non-graphitizable carbon or easily graphitizable carbon) and the like.
  • the negative electrode active material one of these materials may be used alone, or two or more of them may be mixed and used.
  • Graphite refers to a carbon material having an average lattice spacing (d 002 ) of (002) planes determined by X-ray diffraction method before charging / discharging or in a discharged state of 0.33 nm or more and less than 0.34 nm.
  • Examples of graphite include natural graphite and artificial graphite. Artificial graphite is preferable from the viewpoint that a material having stable physical properties can be obtained.
  • Non-graphitic carbon refers to a carbon material having an average lattice spacing (d 002 ) of the (002) plane determined by the X-ray diffraction method before charging / discharging or in a discharged state of 0.34 nm or more and 0.42 nm or less. ..
  • Examples of non-graphitizable carbon include non-graphitizable carbon and easily graphitizable carbon.
  • the non-planar carbon include a resin-derived material, a petroleum pitch or a petroleum pitch-derived material, a petroleum coke or a petroleum coke-derived material, a plant-derived material, an alcohol-derived material, and the like.
  • non-graphitizable carbon refers to a carbon material having d 002 of 0.36 nm or more and 0.42 nm or less.
  • the “graphitizable carbon” refers to a carbon material having d 002 of 0.34 nm or more and less than 0.36 nm.
  • the "discharged state" in the definition of graphite and non-graphical carbon means that the carbon material, which is the negative electrode active material, sufficiently releases ions involved in the charge / discharge reaction that can be occluded and discharged during charge / discharge. It means the state of being discharged as such.
  • the open circuit voltage is 2.0 V or more.
  • the negative electrode active material is usually particles (powder).
  • the average particle size thereof may be 1 ⁇ m or more and 100 ⁇ m or less.
  • the "average particle size” is based on JIS-Z-8825 (2013), and is based on the particle size distribution measured by the laser diffraction / scattering method for a diluted solution obtained by diluting the particles with a solvent.
  • -2 (2001) means a value at which the volume-based integrated distribution calculated in accordance with (2001) is 50%.
  • the average particle size in the particle size distribution of the carbon material is preferably 2.0 ⁇ m or more and 10.0 ⁇ m or less, more preferably 2.5 ⁇ m or more and 9.0 ⁇ m or less, further preferably 3.0 ⁇ m or more and 8.0 ⁇ m or less, and 3.56 ⁇ m.
  • the ultra-less than 7.68 ⁇ m is even more preferable, 3.6 ⁇ m or more and 7.0 ⁇ m or less is further preferable, and 4.0 ⁇ m or more and 6.0 ⁇ m or less is even more preferable.
  • a crusher, a classifier, etc. are used to obtain powder with a predetermined particle size.
  • the crushing method include a method using a mortar, a ball mill, a sand mill, a vibrating ball mill, a planetary ball mill, a jet mill, a counter jet mill, a swirling air flow type jet mill, a sieve, or the like.
  • wet pulverization in which water or an organic solvent such as hexane coexists can also be used.
  • a classification method a sieve, a wind power classifier, or the like is used as needed for both dry type and wet type.
  • the lower limit of the total boron content A of the carbon material is preferably 3.3% by mass, more preferably 4.8% by mass.
  • the upper limit of the total boron content A of the carbon material is preferably 22.0% by mass.
  • the total boron content A of the carbon material is determined by high frequency inductively coupled plasma emission spectroscopy (ICP). As the sample used for the measurement of the ICP, the same sample as the sample used for the measurement of the spectrum of the negative electrode active material by the following X-ray photoelectron spectroscopy is prepared.
  • ICP inductively coupled plasma emission spectroscopy
  • the negative electrode active material is synthesized and prepared after crushing the mortar. It is preferable that the above sample is reheat-treated after synthesis.
  • the sample is prepared from the non-aqueous electrolyte storage element after charging and discharging, the sample is discharged to the discharge end voltage at the time of normal use with a current of 0.1 C to bring it into a completely discharged state.
  • a test battery is manufactured by disassembling the power storage element in a completely discharged state, taking out the negative electrode, using the negative electrode as the working electrode, and using metallic lithium as the counter electrode.
  • This test battery is discharged to 3.0 V (vs. Li / Li + ) at a current density of 50 mAg -1 (per 1 g of negative electrode active material), disassembled again, the negative electrode is taken out, and thoroughly washed with dimethyl carbonate. do. Then, in order to remove the SEI (solid-electrolyte interface) film, the negative electrode is immersed in a solution of water, acid, alkali, organic solvent or the like at a predetermined temperature in an atmosphere of a normal atmosphere for 2 hours. After the immersion, the negative electrode is washed with water and ethanol and dried under reduced pressure (in the case of an aqueous binder, the dropped negative electrode active material layer is recovered by vacuum filtration and then dried).
  • the SEI film may be removed by heat treatment without performing the dipping treatment.
  • the negative electrode can be cut out to a predetermined size (for example, 2 cm ⁇ 2 cm) (in the case of an aqueous binder, the recovered negative electrode active material layer) and used as a sample for XPS spectrum measurement.
  • the battery disassembly work is performed in an argon atmosphere with a dew point of ⁇ 60 ° C. or lower.
  • a carbon tape is attached on the sample holder, and the sample is placed there.
  • the sample holder is introduced into the sample chamber of "AXIS NOVA" manufactured by KRATOS ANALYTICAL, which is an XPS device, and the XPS spectrum is acquired.
  • XPS measurement is performed under a reduced pressure of vacuum degree 5 ⁇ 10 -5 Pa or less.
  • narrow scans are performed 10 times at 272 eV to 300 eV and 181 eV to 201 eV, respectively.
  • the energy values of the B1s and C1s spectra are corrected so that the energy value indicating the maximum intensity of the C1s peak is 284.8 eV.
  • AlK ⁇ is used as an X-ray source, the Emission is 10 mA, and the Anode HT is 15 kV.
  • a neutralization gun is used, and the Filment current is set to 2A, the Charge Balance is set to 3.5V, and the Filment Bias is set to 1.2V.
  • the conditions for narrow scan are a step size of 0.1 eV and a dwell time of 250 ms.
  • the analyzer mode is "Spectrum”
  • the lens mode is "Field of View 1: Survey”
  • the energy resolution is "Pass Energy 40”
  • the analysis area is "slot”.
  • the linear function connecting the points showing the minimum intensity from 182 eV to 186 eV and the points showing the minimum intensity from 196 eV to 200 eV is removed from the B1s spectrum corrected by the energy value as the background.
  • the ratio of the integrated intensity D of B1s in the range of 186 eV or more and 188 eV or less to the integrated intensity E of B1s in the range of 186 eV or more and 196 eV or less is defined as the integrated intensity ratio D / E.
  • the integrated intensity ratio D / E represents the molar ratio of boron doped (forming a boron-carbon bond) by substituting carbon in the graphene layer with respect to the total boron contained in the carbon material.
  • the peaks derived from the boron-carbon bond are drawn to the higher energy side than 188 eV, but when the peaks derived from elemental boron or the boron-nitrogen bond are also detected, the influence of those peaks is affected.
  • the upper limit of the range for obtaining the integrated strength is set to 188 eV.
  • the lower limit of the integrated intensity ratio D / E by the X-ray photoelectron spectroscopy 0.154 is preferable, and 0.176 is more preferable.
  • the lower limit of the integrated intensity ratio D / E is equal to or higher than the above, the Coulomb efficiency in a relatively noble potential region can be increased.
  • the upper limit of the integrated intensity ratio D / E 0.390 is preferable, and 0.380 is more preferable.
  • the upper limit of the integrated strength ratio D / E is not more than the above, both durability can be achieved.
  • the content of boron contained in the carbon material to form a carbon bond that is, the content of boron substituted with carbon in the graphene layer contained in the carbon material, that is, boron in the graphene layer.
  • the lower limit of the content of boron forming a carbon bond is preferably 0.6% by mass, more preferably 1.4% by mass.
  • the upper limit of the content of boron that forms a boron-carbon bond contained in the carbon material is preferably 8.0% by mass.
  • the negative electrode active material can be reliably synthesized.
  • the content of boron that forms a boron-carbon bond contained in the carbon material can be calculated by the above formula 1.
  • the lower limit of G is 0.50, preferably 0.53.
  • the upper limit of the above IV / IG is preferably 0.90.
  • the “spectrum by Raman spectroscopy (Raman spectrum)” is acquired by using a microlaser Raman spectroscopy measuring device "LabRam HR Evolution” manufactured by HORIBA.
  • the laser wavelength is 532 nm
  • the exposure time is 30 seconds
  • the integration is twice
  • the wave number range is 100 cm -1 to 4000 cm -1 .
  • the linear function passing through the point showing the minimum value from 800 cm -1 to 1300 cm -1 and the point showing the minimum value from 1700 cm -1 to 2000 cm -1 is removed as the background.
  • the maximum intensity in the range of 1500 cm -1 or more and 1700 cm -1 or less is defined as IG
  • the minimum intensity in the range of 1400 cm -1 or more and 1550 cm -1 or less is defined as IV .
  • the discharge capacity in a relatively noble potential region can be maintained in a good range.
  • the lower limit of the half-value full width of the (002) plane diffraction peak by the manual method in X-ray diffraction using CuK ⁇ ray of the carbon material contained in the negative electrode active material for the non-aqueous electrolyte power storage element is preferably 0.5 ° or more. 0.0 ° is more preferable, 1.5 ° or more is further preferable, and more than 1.77 ° is even more preferable.
  • the upper limit of the full width at half maximum of the (002) plane diffraction peak is preferably 5.0 ° or less.
  • the discharge capacity in the relatively noble potential region can be maintained in a good range, and when it exceeds 1.77, a comparison is made. It can show a low-key discharge potential.
  • X-ray diffraction measurement For the X-ray diffraction (XRD) measurement of the carbon material contained in the negative electrode active material for the non-aqueous electrolyte power storage element, a powder X-ray diffraction pattern of the sample is obtained using an X-ray diffraction device (manufactured by Rigaku, model name: MiniFlex II). ..
  • the radiation source is CuK ⁇ wire
  • the tube voltage is 30 kV
  • the tube current is 15 mA.
  • the diffracted X-rays pass through a K ⁇ filter having a thickness of 30 ⁇ m and are detected by a high-speed one-dimensional detector (D / teX Ultra 2).
  • the sampling width is 0.02 °
  • the scan speed is 5 ° / min
  • the divergent slit width is 0.625 °
  • the light receiving slit width is 13 mm (OPEN)
  • the scattering slit width is 8 mm.
  • the voltage is obtained in the discharge process of the cell having the working electrode containing the carbon material as the active material and the counter electrode made of metallic lithium.
  • the lower limit of the ratio of the maximum value of dQ / dV in the voltage range of 1.4 V or more and 2.0 V or less to the minimum value of dQ / dV in the range of 1.0 V or more and 1.4 V or less is preferably 1.03. 18 is more preferable.
  • the dQ / dV ratio is relatively noble at about 0.35 V (vs.
  • the Coulomb efficiency in the potential region can be increased. It is considered that the higher the dQ / dV ratio is, the less defects and functional groups are formed in the graphene layer of the carbon material, and the larger the amount of boron doped in the carbon in the graphene layer. As a result, the Coulomb efficiency is expected to increase.
  • the dQ / dV ratio is calculated by the following procedure. First, the non-aqueous electrolyte power storage element is constantly discharged to the lower limit voltage during normal use with a current of 0.05 C. The non-aqueous electrolyte storage element after discharge is disassembled in an inert atmosphere, the negative electrode is taken out, washed with dimethyl carbonate and dried, and the negative electrode is used as the working electrode and the electrode made of metallic lithium is used as the counter electrode. To assemble.
  • the obtained cell is charged with a constant current constant voltage (CCCV) having a charging voltage of 0.4 V at 25 ° C. with a charging current of 50 mA per 1 g of the negative electrode active material.
  • CCCV constant current constant voltage
  • the charge termination condition is 12 hours after the start of constant voltage charging.
  • CC constant current
  • a dQ / dV curve is obtained based on the behavior at the time of constant current discharge.
  • the procedure for obtaining the dQ / dV curve is as follows.
  • the value of the voltage V between the terminals of the cell changes by 0.02 V
  • Q n ) is stored as data.
  • n is a natural number.
  • the value of (Q n + 1 ⁇ Q n ) / (V n + 1 ⁇ V n ) is plotted against the value of (V n + 1 + V n ) / 2 to obtain a dQ / dV curve.
  • the ratio of the maximum value of dQ / dV in the voltage range of 1.4V or more and 2.0V or less to the minimum value of dQ / dV in the voltage range of 1.0V or more and 1.4V or less is dQ /.
  • the dV ratio is the ratio of the maximum value of dQ / dV in the voltage range of 1.4V or more and 2.0V or less to the minimum value of dQ / dV in the voltage range of 1.0V or more and 1.4V or less.
  • the upper limit of the amount of oxygen desorbed from the negative electrode active material at an atmospheric temperature of more than 800 ° C. is preferably 2.45% by mass, more preferably 1.79% by mass with respect to the carbon material.
  • the amount of oxygen desorbed at an atmospheric temperature of more than 800 ° C. is within the above range, the charge / discharge hysteresis can be reduced.
  • the Coulomb efficiency can be improved by reducing the charge / discharge hysteresis.
  • the oxygen desorption amount is measured under the following conditions using an oxygen / nitrogen / hydrogen analyzer "EMGA-930" manufactured by HORIBA as a measuring device.
  • Oxygen detector Inert gas melting-non-dispersive infrared absorption method (NDIR) Sample mass: 20 mg to 25 mg
  • Gas extraction furnace power Impulse furnace output: 0 to 8.0 kW (Check the relationship between output and temperature in advance and change it for each set temperature.)
  • Carrier gas He Calibration method: 1-point calibration using a standard sample Integration condition: Time integration Time integrated for each set temperature (1) 0 seconds to 60 seconds (400 ° C) (2) 60 seconds to 110 seconds (600 ° C) (3) 110 seconds to 160 seconds (800 ° C) (4) 160 seconds to 210 seconds (1000 ° C) (5) 210 seconds to 260 seconds (1200 ° C) (6) 260 seconds to 330 seconds (2500 ° C) Measurement procedure: A graphite crucible is placed in an extraction furnace and baked at 3231 ° C.
  • the crucible is taken out to the atmosphere, 20 mg to 25 mg of the sample is put in the crucible, and the crucible is placed in the extraction furnace again.
  • the temperature is gradually raised in the order of 400 ° C. (50 seconds) ⁇ 600 ° C. (50 seconds) ⁇ 800 ° C. (50 seconds) ⁇ 1000 ° C. (50 seconds) ⁇ 1200 ° C. (50 seconds) ⁇ 2500 ° C. (50 seconds).
  • the amount of oxygen desorbed from the sample at each temperature is quantified.
  • the amount of oxygen desorbed from the crucible alone exposed to the air after air-baking is also measured and the amount is removed. .. That is, the "amount of oxygen desorbed at an atmospheric temperature exceeding 800 ° C.” in the present invention is the total amount of oxygen desorbed when heated at 1000 ° C., 1200 ° C. and 2500 ° C. in the oxygen analysis, that is, the oxygen analysis. Means the integration of oxygen detected from 160.1 seconds to 330 seconds in.
  • the negative electrode active material may be formed only from the above carbon material, and may contain other negative electrode active materials other than the above carbon material as long as the effect of the present invention is exhibited. Further, the negative electrode active material may contain a carbon material other than the above carbon material. Examples of other negative electrode active materials include non-graphitizable carbon other than the above carbon materials, easily graphitizable carbon, other carbon materials such as graphite, semi-metals such as Si, metals such as Sn, these semi-metals or metals. Or the oxide of the above, or a composite of these semi-metals or metals and a carbon material, and the like.
  • the content of the carbon material in the negative electrode active material is preferably 70% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more.
  • the discharge capacity per mass and the Coulomb efficiency in a relatively noble potential region of about 0.35 V (vs. Li / Li + ) or more can be further increased.
  • the method for producing the negative electrode active material is not particularly limited.
  • a method for producing a carbon material containing boron and having a layered crystal structure for example, it can be synthesized by the CVD method.
  • the method for producing a carbon material is to introduce a boron source gas and a raw material gas containing a carbon source gas into a reaction vessel such as a quartz tube and synthesize them by a CVD method at a high temperature in an electric furnace or the like. You may have.
  • the reaction temperature in the synthesis step is preferably 700 ° C. or higher and 1100 ° C. or lower.
  • Examples of the boron source gas for synthesis by the above CVD method include boron halide such as BCl 3 .
  • Examples of the carbon source gas include hydrocarbons such as benzene, acetylene, ethylene, methane, ethane, and propane. Further, it is preferable to use a carrier gas such as nitrogen in addition to the above raw material gas.
  • the precipitated carbon material is recovered and reheated in a vacuum replacement furnace.
  • the reheat treatment step is performed, for example, in a nitrogen atmosphere.
  • the reheat treatment temperature is preferably 600 ° C. or higher and 1000 ° C. or lower.
  • the carbon material after reheat treatment is used as a negative electrode active material after pulverization.
  • the method for crushing the carbon material can be appropriately selected from the above crushing methods.
  • the negative electrode for a non-aqueous electrolyte power storage element contains the negative electrode active material. Since the negative electrode contains the negative electrode active material, it is possible to increase the discharge capacity per mass and the Coulomb efficiency in a relatively noble potential region of about 0.35 V (vs. Li / Li + ) or more.
  • the negative electrode has a negative electrode base material and a negative electrode active material layer arranged directly on the negative electrode base material or via an intermediate layer.
  • the negative electrode substrate has conductivity. Whether or not it has “conductivity” is determined with a volume resistivity of 107 ⁇ ⁇ cm measured in accordance with JIS-H-0505 (1975) as a threshold value.
  • the material of the negative electrode base material include metals such as copper, nickel, stainless steel, nickel-plated steel, and aluminum or alloys thereof, carbonaceous materials, and the like, and the operating potential of the negative electrode is 0.35 V (vs. Li / Li). + ) Or more, it is preferably made of pure aluminum or an aluminum alloy. By further having a negative electrode base material made of pure aluminum or an aluminum alloy, the negative electrode for the non-aqueous electrolyte power storage element can be reduced in cost and weight.
  • “Pure aluminum” refers to aluminum having a purity of 99.00% by mass or more, and examples thereof include aluminum in the 1000s specified in JIS-H4000 (2014). Further, the “aluminum alloy” refers to a metal in which the most contained component is aluminum and the purity of aluminum is less than 99.00% by mass.
  • aluminum other than the 1000 series specified in the above JIS is used. Can be mentioned.
  • Aluminum other than the 1000 series specified in the JIS includes, for example, 2000 series aluminum, 3000 series aluminum, 4000 series aluminum, 5000 series aluminum, 6000 series aluminum, 7000 series aluminum, etc. specified in the above JIS. Can be mentioned.
  • the aluminum purity of the negative electrode base material is preferably 85% or more, more preferably 90% or more, still more preferably 95% or more.
  • the negative electrode base material for example, pure aluminum in the 1000s specified in JIS-H4000 (2014), aluminum-manganese-based alloys in the 3000s, aluminum-magnesium alloys in the 5000s, and the like can be used.
  • Examples of the negative electrode base material include foils and thin-film deposition films, and foils are preferable from the viewpoint of cost. Therefore, aluminum foil or aluminum alloy foil is preferable as the negative electrode base material.
  • the average thickness of the negative electrode substrate is preferably 2 ⁇ m or more and 35 ⁇ m or less, more preferably 3 ⁇ m or more and 30 ⁇ m or less, further preferably 4 ⁇ m or more and 25 ⁇ m or less, and particularly preferably 5 ⁇ m or more and 20 ⁇ m or less.
  • the intermediate layer is a layer arranged between the negative electrode base material and the negative electrode active material layer.
  • the intermediate layer contains a conductive agent such as carbon particles to reduce the contact resistance between the negative electrode base material and the negative electrode active material layer.
  • the composition of the intermediate layer is not particularly limited and includes, for example, a binder and a conductive agent.
  • the negative electrode active material layer contains the negative electrode active material.
  • the negative electrode active material layer contains optional components such as a conductive agent, a binder, a thickener, and a filler, if necessary.
  • the composition of the negative electrode active material is as described above.
  • the content of the negative electrode active material in the negative electrode active material layer is preferably 60% by mass or more and 99% by mass or less, and more preferably 90% by mass or more and 98% by mass or less. By setting the content of the negative electrode active material within the above range, it is possible to achieve both high energy density and manufacturability of the negative electrode active material layer.
  • the carbon material contained in the negative electrode active material also has conductivity, but the negative electrode active material layer preferably contains carbon nanotubes as the conductive agent. Since the negative electrode active material layer contains carbon nanotubes, the coulombic efficiency at the time of overcharging can be improved.
  • Carbon nanotubes are cylindrical fibrous carbon materials. The carbon nanotubes may be single-walled or multi-walled. In addition, one type of carbon nanotube may be used alone, or two or more types may be used in combination.
  • the lower limit of the carbon nanotube content in the negative electrode active material layer is preferably 0.01% by mass, more preferably 0.02% by mass.
  • the upper limit of the content of the carbon nanotubes is preferably 2% by mass, more preferably 1% by mass.
  • the lower limit of the average length of the carbon nanotubes is preferably 3 ⁇ m, more preferably 5 ⁇ m.
  • the upper limit of the average length of the carbon nanotubes is preferably 300 ⁇ m, more preferably 200 ⁇ m.
  • the negative electrode active material layer may contain other conductive agents other than carbon nanotubes.
  • the other conductive agent is not particularly limited as long as it is a conductive material.
  • Examples of such a conductive agent include carbonaceous materials, metals, conductive ceramics and the like.
  • Examples of the carbonaceous material include graphitized carbon, non-graphitized carbon, graphene-based carbon and the like.
  • Examples of the non-graphitized carbon include carbon nanofibers, pitch-based carbon fibers, and carbon black.
  • Examples of carbon black include furnace black, acetylene black, and ketjen black.
  • Examples of graphene-based carbons include graphene and fullerenes.
  • Examples of the shape of the other conductive agent include powder and fibrous.
  • the other conductive agent one of these materials may be used alone, or two or more of them may be mixed and used. Further, these materials may be used in combination.
  • carbon black is preferable as the other conductive agent from the viewpoint of electron conductivity and coatability, and acetylene black is particularly preferable.
  • the total content of the conductive agent in the negative electrode active material layer is preferably 1% by mass or more and 10% by mass or less, and more preferably 3% by mass or more and 9% by mass or less.
  • binder examples include fluororesins (polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), etc.), thermoplastic resins such as polyethylene, polypropylene, polyacrylics, and polyimides; ethylene-propylene-diene rubber (EPDM), sulfone. Elastomers such as polyethylene chemicals, styrene butadiene rubber (SBR), fluororubber; and polysaccharide polymers can be mentioned.
  • fluororesins polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), etc.
  • thermoplastic resins such as polyethylene, polypropylene, polyacrylics, and polyimides
  • EPDM ethylene-propylene-diene rubber
  • SBR styrene butadiene rubber
  • fluororubber styrene butadiene rubber
  • polysaccharide polymers can be mentioned.
  • the binder content in the negative electrode active material layer is preferably 1% by mass or more and 10% by mass or less, and more preferably 3% by mass or more and 9% by mass or less. By setting the binder content within the above range, the negative electrode active material can be stably held.
  • the thickener examples include polysaccharide polymers such as carboxymethyl cellulose (CMC) and methyl cellulose.
  • CMC carboxymethyl cellulose
  • methyl cellulose examples include polysaccharide polymers such as carboxymethyl cellulose (CMC) and methyl cellulose.
  • this functional group may be deactivated by methylation or the like in advance.
  • the filler is not particularly limited.
  • Fillers include polyolefins such as polypropylene and polyethylene, silicon dioxide, alumina, titanium dioxide, calcium oxide, strontium oxide, barium oxide, magnesium oxide, inorganic oxides such as aluminosilicate, magnesium hydroxide, calcium hydroxide, and hydroxide.
  • Hydroxides such as aluminum, carbonates such as calcium carbonate, sparingly soluble ion crystals such as calcium fluoride, barium fluoride, barium sulfate, nitrides such as aluminum nitride and silicon nitride, talc, montmorillonite, boehmite, zeolite, etc.
  • mineral resource-derived substances such as apatite, kaolin, mulite, spinel, olivine, sericite, bentonite, and mica, or man-made products thereof.
  • the negative electrode active material layer is a typical non-metal element such as B, N, P, F, Cl, Br, I, Li, Na, Mg, Al, K, Ca, Zn, Ga, Ge, Sn, Sr, Ba, etc.
  • Typical metal elements such as Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Mo, Zr, Ta, Hf, Nb, W and other transition metal elements are used as negative electrode active materials, conductive agents, binders, etc. It may be contained as a component other than a thickener and a filler.
  • the non-aqueous electrolyte power storage element (hereinafter, also simply referred to as “storage element”) according to the embodiment of the present invention includes an electrode body having a positive electrode, a negative electrode and a separator, a non-aqueous electrolyte, and the above-mentioned electrode body and non-water electrolyte. It is equipped with a container for accommodating.
  • the electrode body is usually a laminated type in which a plurality of positive electrodes and a plurality of negative electrodes are laminated via a separator, or a wound type in which a positive electrode and a negative electrode are laminated via a separator.
  • the non-aqueous electrolyte exists in a state of being impregnated in the positive electrode, the negative electrode and the separator.
  • a non-aqueous electrolyte secondary battery hereinafter, also simply referred to as “secondary battery”.
  • the non-aqueous electrolyte power storage element includes the negative electrode for the non-water electrolyte power storage element. Since the non-aqueous electrolyte power storage element includes a negative electrode containing the negative electrode active material, the discharge capacity per mass and the Coulomb efficiency in a relatively noble potential region of about 0.35 V (vs. Li / Li + ) or more can be obtained. Can be enhanced.
  • the positive electrode has a positive electrode base material and a positive electrode active material layer arranged directly on the positive electrode base material or via an intermediate layer.
  • the configuration of the intermediate layer is not particularly limited, and can be selected from, for example, the configurations exemplified by the negative electrode.
  • the positive electrode base material has conductivity.
  • a metal such as aluminum, titanium, tantalum, or stainless steel or an alloy thereof is used.
  • aluminum or an aluminum alloy is preferable from the viewpoint of potential resistance, high conductivity, and cost.
  • the positive electrode base material include foils, thin-film deposition films, meshes, porous materials, and the like, and foils are preferable from the viewpoint of cost. Therefore, aluminum foil or aluminum alloy foil is preferable as the positive electrode base material.
  • Examples of aluminum or aluminum alloy include A1085, A3003, and A1N30 specified in JIS-H-4000 (2014) or JIS-H4160 (2006).
  • the average thickness of the positive electrode substrate is preferably 3 ⁇ m or more and 50 ⁇ m or less, more preferably 5 ⁇ m or more and 40 ⁇ m or less, further preferably 8 ⁇ m or more and 30 ⁇ m or less, and particularly preferably 10 ⁇ m or more and 25 ⁇ m or less.
  • the positive electrode active material layer contains the positive electrode active material.
  • the positive electrode active material layer contains optional components such as a conductive agent, a binder, a thickener, and a filler, if necessary.
  • the positive electrode active material can be appropriately selected from known positive electrode active materials.
  • As the positive electrode active material for a lithium ion secondary battery a material capable of storing and releasing lithium ions is usually used.
  • Examples of the positive electrode active material include a lithium transition metal composite oxide having an ⁇ -NaFeO type 2 crystal structure, a lithium transition metal composite oxide having a spinel type crystal structure, a polyanionic compound, a chalcogen compound, sulfur and the like.
  • Examples of the lithium transition metal composite oxide having an ⁇ -NaFeO type 2 crystal structure include Li [Li x Ni (1-x) ] O 2 (0 ⁇ x ⁇ 0.5) and Li [Li x Ni ⁇ Co ( 0 ⁇ x ⁇ 0.5).
  • Examples of the lithium transition metal composite oxide having a spinel-type crystal structure include Li x Mn 2 O 4 and Li x Ni ⁇ Mn (2- ⁇ ) O 4 .
  • Examples of the polyanionic compound include LiFePO 4 , LiMnPO 4 , LiNiPO 4 , LiCoPO 4 , Li 3 V 2 (PO 4 ) 3 , Li 2 MnSiO 4 , Li 2 CoPO 4 F and the like.
  • Examples of the chalcogen compound include titanium disulfide, molybdenum disulfide, molybdenum dioxide and the like.
  • the atoms or polyanions in these materials may be partially substituted with atoms or anion species consisting of other elements.
  • the surface of these materials may be coated with other materials. In the positive electrode active material layer, one of these materials may be used alone, or two or more of them may be mixed and used.
  • the positive electrode active material is usually particles (powder).
  • the average particle size of the positive electrode active material is preferably 0.1 ⁇ m or more and 20 ⁇ m or less, for example. By setting the average particle size of the positive electrode active material to the above lower limit or more, the production or handling of the positive electrode active material becomes easy. By setting the average particle size of the positive electrode active material to the above upper limit or less, the electron conductivity of the positive electrode active material layer is improved. When a composite of a positive electrode active material and another material is used, the average particle size of the composite is taken as the average particle size of the positive electrode active material. A crusher, a classifier, or the like is used to obtain a powder having a predetermined particle size. The pulverization method and the powder grade method can be selected from, for example, the methods exemplified for the negative electrode.
  • the content of the positive electrode active material in the positive electrode active material layer is preferably 50% by mass or more and 99% by mass or less, more preferably 70% by mass or more and 98% by mass or less, and further preferably 80% by mass or more and 95% by mass or less.
  • the conductive agent is not particularly limited as long as it is a conductive material.
  • the conductive agent can be selected from the materials exemplified for the negative electrode.
  • the content of the conductive agent in the positive electrode active material layer is preferably 1% by mass or more and 10% by mass or less, and more preferably 3% by mass or more and 9% by mass or less.
  • the binder can be selected from the materials exemplified for the negative electrode.
  • the binder content in the positive electrode active material layer is preferably 1% by mass or more and 10% by mass or less, and more preferably 3% by mass or more and 9% by mass or less. By setting the binder content within the above range, the active substance can be stably retained.
  • the thickener can be selected from the materials exemplified in the negative electrode.
  • the filler can be selected from the materials exemplified for the negative electrode.
  • the positive electrode active material layer includes typical non-metal elements such as B, N, P, F, Cl, Br, I, Li, Na, Mg, Al, K, Ca, Zn, Ga, Ge, Sn, Sr, Ba and the like.
  • Typical metal elements such as Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Mo, Zr, Nb, W and other transition metal elements are used as positive electrode active materials, conductive agents, binders, thickeners, fillers. It may be contained as a component other than.
  • the negative electrode is a negative electrode for a non-aqueous electrolyte power storage element according to an embodiment of the present invention.
  • the details of the negative electrode are as described above.
  • the lower limit of the negative electrode potential at the end of charging voltage during normal use is preferably 0.35 V (vs. Li / Li + ), more preferably 0.40 V (vs. Li / Li + ).
  • 0.60 V (vs. Li / Li + ) is even more preferable.
  • the separator can be appropriately selected from known separators.
  • a separator composed of only a base material layer a separator having a heat-resistant layer containing heat-resistant particles and a binder formed on one surface or both surfaces of the base material layer can be used.
  • Examples of the shape of the base material layer of the separator include woven fabrics, non-woven fabrics, and porous resin films. Among these shapes, a porous resin film is preferable from the viewpoint of strength, and a non-woven fabric is preferable from the viewpoint of liquid retention of a non-aqueous electrolyte.
  • polyolefins such as polyethylene and polypropylene are preferable from the viewpoint of shutdown function, and polyimide and aramid are preferable from the viewpoint of oxidative decomposition resistance.
  • base material layer of the separator a material in which these resins are combined may be used.
  • the heat-resistant particles contained in the heat-resistant layer preferably have a mass reduction of 5% or less when the temperature is raised from room temperature to 500 ° C. in an air atmosphere of 1 atm, and the mass reduction when the temperature is raised from room temperature to 800 ° C. Is more preferably 5% or less.
  • Inorganic compounds can be mentioned as materials whose mass reduction is less than or equal to a predetermined value. Examples of the inorganic compound include oxides such as iron oxide, silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, calcium oxide, strontium oxide, barium oxide, magnesium oxide and aluminosilicate; nitrides such as aluminum nitride and silicon nitride.
  • Carbonates such as calcium carbonate; Sulfates such as barium sulfate; sparingly soluble ion crystals such as calcium fluoride, barium fluoride, barium titanate; covalent crystals such as silicon and diamond; talc, montmorillonite, boehmite, Examples thereof include mineral resource-derived substances such as zeolite, apatite, kaolin, mulite, spinel, olivine, sericite, bentonite, and mica, or man-made products thereof.
  • the inorganic compound a simple substance or a complex of these substances may be used alone, or two or more kinds thereof may be mixed and used.
  • silicon oxide, aluminum oxide, or aluminosilicate is preferable from the viewpoint of safety of the power storage device.
  • the porosity of the separator is preferably 80% by volume or less from the viewpoint of strength, and preferably 20% by volume or more from the viewpoint of discharge performance.
  • the "porosity" is a volume-based value and means a measured value with a mercury porosity meter.
  • a polymer gel composed of a polymer and a non-aqueous electrolyte may be used.
  • the polymer include polyacrylonitrile, polyethylene oxide, polypropylene oxide, polymethyl methacrylate, polyvinyl acetate, polyvinylpyrrolidone, polyvinylidene fluoride and the like.
  • the use of polymer gel has the effect of suppressing liquid leakage.
  • a polymer gel may be used in combination with a porous resin film or a non-woven fabric as described above.
  • Non-water electrolyte As the non-aqueous electrolyte, a known non-aqueous electrolyte can be appropriately selected. A non-aqueous electrolyte solution may be used as the non-aqueous electrolyte.
  • the non-aqueous electrolyte solution contains a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent.
  • the non-aqueous solvent can be appropriately selected from known non-aqueous solvents.
  • the non-aqueous solvent include cyclic carbonates, chain carbonates, carboxylic acid esters, phosphoric acid esters, sulfonic acid esters, ethers, amides, nitriles and the like.
  • a solvent in which some of the hydrogen atoms contained in these compounds are replaced with halogen may be used.
  • cyclic carbonate examples include ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), vinylene carbonate (VC), vinyl ethylene carbonate (VEC), chloroethylene carbonate, fluoroethylene carbonate (FEC), and difluoroethylene carbonate.
  • EC and PC are preferable, and PC is particularly preferable. By using a PC, it is possible to show an excellent high rate charge electricity amount ratio.
  • chain carbonate examples include diethyl carbonate (DEC), dimethyl carbonate (DMC), ethylmethyl carbonate (EMC), diphenyl carbonate, trifluoroethylmethyl carbonate, bis (trifluoroethyl) carbonate and the like.
  • DEC diethyl carbonate
  • DMC dimethyl carbonate
  • EMC ethylmethyl carbonate
  • diphenyl carbonate trifluoroethylmethyl carbonate
  • bis (trifluoroethyl) carbonate bis (trifluoroethyl) carbonate and the like.
  • DEC and EMC are preferable, and DEC is particularly preferable.
  • the non-aqueous solvent it is preferable to use cyclic carbonate or chain carbonate, and it is more preferable to use cyclic carbonate and chain carbonate in combination.
  • the cyclic carbonate By using the cyclic carbonate, the dissociation of the electrolyte salt can be promoted and the ionic conductivity of the non-aqueous electrolyte solution can be improved.
  • the chain carbonate By using the chain carbonate, the viscosity of the non-aqueous electrolytic solution can be kept low.
  • the volume ratio of the cyclic carbonate to the chain carbonate is preferably in the range of, for example, 5:95 to 50:50.
  • the electrolyte salt can be appropriately selected from known electrolyte salts.
  • Examples of the electrolyte salt include lithium salt, sodium salt, potassium salt, magnesium salt, onium salt and the like. Of these, lithium salts are preferred.
  • lithium salt examples include inorganic lithium salts such as LiPF 6 , LiPO 2 F 2 , LiBF 4 , LiClO 4 , LiN (SO 2 F) 2 , lithium bis (oxalate) borate (LiBOB), and lithium difluorooxalate borate (LiFOB).
  • inorganic lithium salts such as LiPF 6 , LiPO 2 F 2 , LiBF 4 , LiClO 4 , LiN (SO 2 F) 2 , lithium bis (oxalate) borate (LiBOB), and lithium difluorooxalate borate (LiFOB).
  • Lithium oxalate salts such as lithium bis (oxalate) difluorophosphate (LiFOP), LiSO 3 CF 3 , LiN (SO 2 CF 3 ) 2 , LiN (SO 2 C 2 F 5 ) 2 , LiN (SO 2 CF 3 )
  • LiFOP lithium bis (oxalate) difluorophosphate
  • LiSO 3 CF 3 LiN (SO 2 CF 3 ) 2
  • LiN (SO 2 C 2 F 5 ) 2 LiN (SO 2 CF 3 )
  • lithium salts having a halogenated hydrocarbon group such as (SO 2 C 4 F 9 ), LiC (SO 2 CF 3 ) 3 , and LiC (SO 2 C 2 F 5 ) 3
  • an inorganic lithium salt is preferable, and LiPF 6 is more preferable.
  • the content of the electrolyte salt in the non-aqueous electrolyte solution is preferably 0.1 mol / dm 3 or more and 2.5 mol / dm 3 or less, and 0.3 mol / dm 3 or more and 2.0 mol / dm at 20 ° C. and 1 atm. It is more preferably 3 or less, more preferably 0.5 mol / dm 3 or more and 1.7 mol / dm 3 or less, and particularly preferably 0.7 mol / dm 3 or more and 1.5 mol / dm 3 or less.
  • the non-aqueous electrolyte solution may contain additives in addition to the non-aqueous solvent and the electrolyte salt.
  • additives include halogenated carbonates such as fluoroethylene carbonate (FEC) and difluoroethylene carbonate (DFEC); lithium bis (oxalate) borate (LiBOB), lithium difluorooxalate borate (LiFOB), lithium bis (oxalate).
  • Difluorophosphate LiFOP and other oxalates
  • Lithiumbis (fluorosulfonyl) imide (LiFSI) and other imide salts biphenyl, alkylbiphenyl, terphenyl, partially hydride of turphenyl, cyclohexylbenzene, t-butylbenzene , T-Amylbenzene, diphenyl ether, dibenzofuran and other aromatic compounds; partial halides of the aromatic compounds such as 2-fluorobiphenyl, o-cyclohexylfluorobenzene, p-cyclohexylfluorobenzene; 2,4-difluoroanisole, 2 , 5-Difluoroanisole, 2,6-difluoroanisole, 3,5-difluoroanisole and other halogenated anisole compounds; vinylene carbonate, methylvinylene carbonate, ethylvinylene
  • Citraconic acid glutaconic anhydride, itaconic anhydride, cyclohexanedicarboxylic acid anhydride; ethylene sulfite, propylene sulfite, dimethyl sulfite, methyl methanesulfonate, busulfane, methyl toluenesulfonate, dimethyl sulfate, ethylene sulfate, sulfolane, dimethylsulfone, diethyl.
  • the content of the additive contained in the non-aqueous electrolytic solution is preferably 0.01% by mass or more and 10% by mass or less, and is 0.1% by mass or more and 7% by mass or less with respect to the total mass of the non-aqueous electrolytic solution. It is more preferable to have it, more preferably 0.2% by mass or more and 5% by mass or less, and particularly preferably 0.3% by mass or more and 3% by mass or less.
  • non-aqueous electrolyte a solid electrolyte may be used, or a non-aqueous electrolyte solution and a solid electrolyte may be used in combination.
  • the solid electrolyte can be selected from any material having ionic conductivity such as lithium, sodium and calcium and being solid at room temperature (for example, 15 ° C to 25 ° C).
  • Examples of the solid electrolyte include sulfide solid electrolytes, oxide solid electrolytes, oxynitride solid electrolytes, polymer solid electrolytes, gel polymer electrolytes and the like.
  • lithium ion secondary battery examples include Li 2 SP 2 S 5, Li I-Li 2 SP 2 S 5 , Li 10 Ge -P 2 S 12 and the like as the sulfide solid electrolyte.
  • the shape of the non-aqueous electrolyte power storage element of the present embodiment is not particularly limited, and examples thereof include a cylindrical battery, a square battery, a flat battery, a coin battery, and a button battery.
  • FIG. 1 shows a non-aqueous electrolyte power storage element 1 as an example of a square battery.
  • the figure is a perspective view of the inside of the container.
  • the electrode body 2 having the positive electrode and the negative electrode wound around the separator is housed in the square container 3.
  • the positive electrode is electrically connected to the positive electrode terminal 4 via the positive electrode lead 41.
  • the negative electrode is electrically connected to the negative electrode terminal 5 via the negative electrode lead 51.
  • the structure of the non-aqueous electrolyte power storage element of the present embodiment is not particularly limited, and can be applied to, for example, a bipolar structure other than the structure shown in FIG.
  • the power storage device of the present embodiment includes two or more non-aqueous electrolyte power storage elements and one or more non-water electrolyte power storage elements of the present embodiment. Since the power storage element includes one or more non-aqueous electrolyte power storage elements, it is possible to increase the discharge capacity per mass and the Coulomb efficiency in a relatively noble potential region.
  • the non-aqueous electrolyte power storage element of the present embodiment is a power source for automobiles such as an electric vehicle (EV), a hybrid vehicle (HEV), and a plug-in hybrid vehicle (PHEV), a power source for electronic devices such as a personal computer and a communication terminal, or a power source.
  • EV electric vehicle
  • HEV hybrid vehicle
  • PHEV plug-in hybrid vehicle
  • FIG. 2 shows an example of a power storage device 30 in which a power storage unit 20 in which two or more electrically connected non-aqueous electrolyte power storage elements 1 are assembled is further assembled.
  • the power storage device 30 includes a bus bar (not shown) for electrically connecting two or more non-aqueous electrolyte power storage elements 1, a bus bar (not shown) for electrically connecting two or more power storage units 20 and the like. May be good.
  • the power storage unit 20 or the power storage device 30 may include a condition monitoring device (not shown) for monitoring the state of one or more non-aqueous electrolyte power storage elements.
  • the non-aqueous electrolyte power storage device of the present embodiment can be manufactured by a known method except that the negative electrode is prepared as a negative electrode.
  • the manufacturing method includes, for example, preparing an electrode body, preparing a non-aqueous electrolyte, and accommodating the electrode body and the non-aqueous electrolyte in a container.
  • Preparing the electrode body includes preparing the positive electrode body and the negative electrode body, and forming the electrode body by laminating or winding the positive electrode body and the negative electrode body via the separator.
  • the storage of the non-aqueous electrolyte in the container can be appropriately selected from known methods.
  • a non-aqueous electrolyte solution may be used as the non-aqueous electrolyte solution, the non-aqueous electrolyte solution may be injected from the injection port formed in the container, and then the injection port may be sealed.
  • the non-aqueous electrolyte power storage device of the present invention is not limited to the above embodiment, and various modifications may be made without departing from the gist of the present invention.
  • the configuration of one embodiment can be added to the configuration of another embodiment, and a part of the configuration of one embodiment can be replaced with the configuration of another embodiment or a well-known technique.
  • some of the configurations of certain embodiments can be deleted.
  • a well-known technique can be added to the configuration of a certain embodiment.
  • non-aqueous electrolyte storage element is used as a chargeable / dischargeable non-aqueous electrolyte secondary battery (for example, a lithium ion secondary battery) has been described.
  • the capacity etc. are arbitrary.
  • the present invention can also be applied to capacitors such as various secondary batteries, electric double layer capacitors and lithium ion capacitors.
  • Example 1 The graphite sheet PF110 as a base material was installed in a quartz tube (inner diameter 45 mm) of MPCVD-Powder (manufactured by MICROPHASE) (hereinafter, also referred to as a small CVD device). Under a nitrogen stream, the temperature of the quartz tube near the substrate was raised from room temperature to 1000 ° C. at a temperature rise rate of 10 ° C./min. After reaching 1000 ° C., the raw material gas and the carrier gas were flowed into the quartz tube at the gas ratios shown in Table 1, and the carbon material was deposited on the substrate over 5 hours by the chemical vapor deposition (CVD) method. rice field.
  • CVD chemical vapor deposition
  • Example 1 the carbon material which was pulverized with an alumina mortar after the reheat treatment was designated as Example 1.
  • Example 2 After synthesizing the carbon material by the CVD method of Example 1, after taking out the base material, the carbon material remaining in the quartz tube was recovered and pulverized in an alumina mortar to obtain Example 2.
  • Example 3 After recovering the carbon material that had undergone the same steps as in Example 2 except that the conditions shown in Table 1 were performed, reheat treatment was performed in the same manner as in Example 1. Then, the carbon material which was pulverized in the alumina mortar after the reheat treatment was referred to as Example 3.
  • Example 4 Example 5, Example 7 to Example 10, Example 13, Example 15, Example 18, Example 20, Example 23, Example 25, Example 27, Example 35 and comparison Example 3]
  • Example 4 Example 5, Example 7 to Example 10, Example 13, Example 15, Example 18, Example 20, Example 23, Example 25, Example 27, Example 35 and Comparative Example. No. 3 was synthesized in the same manner as in Example 3 except that it was carried out under the conditions shown in Table 1.
  • Example 6 Example 11, Example 12, Example 14, Example 16, Example 17, Example 19, Example 21, Example 22, Example 24, Example 26, Example 34 and comparison.
  • Example 1 Example 6, Example 11, Example 12, Example 14, Example 16, Example 17, Example 19, Example 21, Example 22, Example 24, Example 26, Example 34 and Comparative Example. No. 1 was synthesized in the same manner as in Example 1 except that it was carried out under the conditions shown in Table 1.
  • Example 30 to 33 The carbon materials obtained in the same manner as in Example 1 except that the carbon material was pulverized by a ball mill under the conditions shown in Table 5 were designated as Examples 30 to 33.
  • the processing time of the ball mill was 8 hours.
  • Example 36 The graphite sheet PF110 as a base material was placed in a quartz tube (inner diameter 94 mm, length 1200 mm) of a large CVD apparatus, and synthesized in the same manner as in Example 1 except that the conditions shown in Table 1 were used.
  • Example 37 The graphite sheet PF110 as a base material was placed in a quartz tube (inner diameter 94 mm, length 1200 mm) of a large CVD apparatus, and synthesized in the same manner as in Example 3 except that the conditions shown in Table 1 were used.
  • Comparative Example 2 After recovering the carbon material that had undergone the same steps as in Example 2 except that the conditions shown in Table 1 were performed, the carbon material was placed in an alumina boat (length 125 mm, width 34 mm) and placed in a gas atmosphere tube furnace. It was installed in an alumina core tube (length 800 mm, diameter 42 mm) manufactured by Tanaka Tech. Then, the temperature was raised from normal temperature to 1300 ° C. at a heating rate of 5 ° C./min at a normal pressure under a nitrogen stream of 0.1 L / min, held for 1 hour, and reheat-treated. Then, the carbon material which was pulverized in an alumina mortar after the reheat treatment was designated as Comparative Example 2.
  • Coal tar pitch MCP-110C manufactured by JFE Chemical Co., Ltd.
  • a quartz tube inner diameter 45 mm
  • MPCVD-Powder manufactured by MICROPHASE
  • the temperature of the quartz tube near the boat was raised from room temperature to 1000 ° C at a temperature rise rate of 5 ° C / min.
  • the raw material gas and the carrier gas were passed through the quartz tube at the gas ratios shown in Table 1 and heat-treated for 2 hours. After that, the introduction of the raw material gas was stopped, the boat was allowed to cool from 1000 ° C.
  • An alumina crucible containing 4 g of the obtained graphite oxide was installed in a tabletop vacuum gas replacement furnace KDF75 (manufactured by Denken Hydental Co., Ltd.). Next, the temperature was raised from normal temperature to 170 ° C. at a heating rate of 1 ° C./min at a normal pressure under a nitrogen stream of 0.6 L / min, and further from 170 ° C. at a heating rate of 0.1 ° C./min. After raising the temperature to 250 ° C., the mixture was allowed to cool to room temperature.
  • the obtained graphite oxide after the preliminary heat treatment was placed on a graphite sheet PF110 as a base material, and the base material was placed in a quartz tube (inner diameter 45 mm) of MPCVD-Powder (manufactured by MICROPHASE). Under a nitrogen stream, the temperature of the quartz tube near the substrate was raised from room temperature to 1000 ° C. at a heating rate of 5 ° C./min. After reaching 1000 ° C., the raw material gas and the carrier gas were passed through the quartz tube at the gas ratios shown in Table 1 and heat-treated for 2 hours. Then, the introduction of the raw material gas was stopped, the mixture was allowed to cool from 1000 ° C. to room temperature, and the base material was taken out from the quartz tube.
  • MPCVD-Powder manufactured by MICROPHASE
  • the carbon material was recovered from the substrate. This carbon material was placed in an alumina crucible having a volume of 30 mL and installed in a tabletop vacuum gas replacement furnace KDF75 (manufactured by Denken Hydental). Then, the temperature was raised from normal temperature to 900 ° C. at a heating rate of 5 ° C./min at normal pressure under a nitrogen stream of 0.5 L / min, held for 1 hour, and reheat-treated. Then, the carbon material which was pulverized with an alumina mortar after the reheat treatment was designated as Comparative Example 5.
  • Example 1 to Example 27 The carbon material according to Example 1 to Example 27, Example 30 to Example 37, Comparative Example 1 to Comparative Example 5, and Reference Example 1 to Reference Example 5 was used as the negative electrode active material, and a negative electrode was prepared by the following procedure. .. Polyvinylidene fluoride (PVDF) was used as the binder. A negative electrode mixture paste containing the negative electrode active material and the binder in a mass ratio of 88:12 and using N-methylpyrrolidone as a dispersion medium was prepared.
  • PVDF Polyvinylidene fluoride
  • a negative electrode mixture paste was applied, dried, and pressed on a copper foil having a thickness of 20 ⁇ m as a negative electrode base material to prepare a negative electrode for a non-aqueous electrolyte power storage element in which a negative electrode active material layer was arranged on the negative electrode base material.
  • the initial electrochemical characteristics of the non-aqueous electrolyte power storage element having the negative electrode as the working electrode and the metallic lithium as the counter electrode under the charge / discharge conditions described later are such that the negative electrode using the aluminum foil as the negative electrode base material is the working electrode and the metal. It is equivalent to the initial electrochemical characteristics of the non-aqueous electrolyte power storage element having lithium as the counter electrode.
  • the negative electrode for the non-aqueous electrolyte power storage element in which the negative electrode active material layer is arranged in a rectangular shape having a width of 30 mm and a length of 40 mm is used as a working electrode for an evaluation test.
  • a non-aqueous electrolyte power storage element was manufactured.
  • a rectangular metallic lithium having a width of 32 mm and a length of 42 mm was used as the counter electrode.
  • a polyethylene microporous membrane was used as the separator.
  • Non-aqueous electrolyte LiPF 6 is dissolved in a mixed solvent in which ethylene carbonate (EC): dimethyl carbonate (DMC): ethylmethyl carbonate (EMC) is mixed at a volume ratio of 30:35:35 at a concentration of 1 mol / dm 3 .
  • EC ethylene carbonate
  • DMC dimethyl carbonate
  • EMC ethylmethyl carbonate
  • a pouch cell infused with the non-aqueous electrolyte was prepared by facing the working electrode and the counter electrode through the separator.
  • Examples 38 to 42 A non-aqueous electrolyte power storage device was obtained in the same manner as in Example 1 except that the non-aqueous electrolyte composition was as shown in Table 7.
  • Example 28 Using the carbon material according to Example 28 as the negative electrode active material, the negative electrode active material, carbon nanotube as a conductive agent, styrene butadiene rubber as a binder, and carboxymethyl cellulose as a thickener are 96.6: 0.1: 2.
  • the non-aqueous electrolyte power storage element of Example 28 was obtained.
  • Example 29 The carbon material according to Example 29 is used as the negative electrode active material, and the negative electrode active material, styrene-butadiene rubber as a binder, and carboxymethyl cellulose as a thickener are contained in a mass ratio of 96.7: 2.1: 1.2. Then, a negative electrode mixture paste using water as a dispersion medium was prepared, and a non-aqueous electrolyte power storage element of Example 29 was obtained in the same manner as in Example 22 except that an aluminum foil having a thickness of 20 ⁇ m was used as the negative electrode base material. ..
  • the total boron content (mass%) of the negative electrode active material according to Example 1 to Example 29, Comparative Example 1 to Comparative Example 5, and Reference Example 3 to Reference Example 5 was measured by ICP according to the following procedure. rice field. First, the negative electrode active material was completely dissolved in nitric acid by the microwave decomposition method. Next, this solution was made up to a certain amount with pure water to prepare a measurement solution. Then, the boron concentration of the above-mentioned measurement solution was measured by ICP emission spectroscopic analysis using a multi-type ICP emission spectroscopic analyzer ICPE-9820 (manufactured by Shimadzu Corporation).
  • the total boron content in the negative electrode active material was quantified.
  • a calibration curve method was used in which a calibration curve was prepared from a solution having a known boron concentration and the boron concentration of the measurement solution was obtained.
  • Table 2 shows the evaluation results of Example 1 to Example 27, Example 34 to Example 37, Comparative Example 1 to Comparative Example 5, and Reference Example 1 to Reference Example 5.
  • the non-aqueous electrolyte power storage elements of Examples 28 and 29 were subjected to two cycles of initial charge / discharge in the same manner as described above.
  • the current that reaches the discharge capacity of the second cycle in 1 hour was set to 1C.
  • the overcharge test was carried out according to the procedure shown below.
  • the charging time was 1.5 hours, and CC charging was performed with a charging current of 1 C.
  • a rest period of 10 minutes was provided, and CC discharge with a discharge end voltage of 2.0 V was performed with a discharge current of 1 C.
  • CC discharge with a discharge end voltage of 2.0 V was performed with a discharge current of 0.1 C.
  • Table 4 shows the Coulomb efficiency at the time of overcharging as the percentage of the sum of the discharge capacities with respect to the amount of electricity charged at this time.
  • a 10-minute pause was provided after charging, and CC discharge with a discharge end voltage of 2.0 V was performed with a discharge current of 1 C.
  • a constant current constant voltage (CCCV) charge with a charge termination voltage of 0.4 V was performed with a charge current of 0.1 C with a pause time of 10 minutes after the discharge.
  • the charging termination condition was 12 hours after the start of constant voltage charging.
  • the percentage of the 2C charging electricity amount with respect to the charging electricity amount at this time was defined as the high rate charging electricity amount ratio. The results are shown in Table 7.
  • the negative electrode active materials of Examples 1 to 27 having an IV / IG of 0.5 or more and 0.6% by mass or more were superior in discharge capacity and Coulomb efficiency to Comparative Examples 1 to 5. .. Further, the negative electrode active material was superior in discharge capacity and Coulomb efficiency to graphite, non-graphitizable carbon, graphite oxide, pitch-based carbon and boron carbide of Reference Examples 1 to 5.
  • Example 28 the non-aqueous electrolyte power storage element of Example 28 containing carbon nanotubes as a conductive agent in the negative electrode had higher Coulomb efficiency at the time of overcharging as compared with Example 29.
  • the negative electrode active material for the non-aqueous electrolyte power storage element can obtain good charge / discharge performance in a relatively noble potential region of about 0.35 V (vs. Li / Li + ) or more. rice field.
  • the present invention can be applied to electronic devices such as personal computers and communication terminals, non-aqueous electrolyte power storage elements used as power sources for automobiles, and negative electrodes and negative electrode active materials provided therein.
  • Non-aqueous electrolyte power storage element 1
  • Electrode body 3
  • Container 4
  • Positive terminal 4
  • Negative terminal 51
  • Negative lead 20
  • Power storage unit 30
  • Power storage device

Abstract

A negative electrode active material for nonaqueous electrolyte power storage elements according to one aspect of the present invention contains a carbon material which contains boron, while having a layered crystal structure; the content of boron forming a boron-carbon bond in the carbon material is 0.6% by mass or more; and the ratio of the minimum intensity IV within the range of 1400 cm-1 to 1550 cm-1 to the maximum intensity IG within the range of 1500 cm-1 to 1700 cm-1, namely IV/IG is 0.5 or more in the spectrum of the carbon material obtained by means of Raman spectroscopy.

Description

非水電解質蓄電素子用負極活物質、非水電解質蓄電素子用負極、非水電解質蓄電素子及び蓄電装置Negative electrode active material for non-aqueous electrolyte power storage element, negative electrode for non-water electrolyte power storage element, non-water electrolyte power storage element and power storage device
　本発明は、非水電解質蓄電素子用負極活物質、非水電解質蓄電素子用負極、非水電解質蓄電素子及び蓄電装置に関する。 The present invention relates to a negative electrode active material for a non-aqueous electrolyte power storage element, a negative electrode for a non-aqueous electrolyte power storage element, a non-aqueous electrolyte power storage element, and a power storage device.
　リチウムイオン非水電解質二次電池に代表される非水電解質二次電池は、エネルギー密度の高さから、パーソナルコンピュータ、通信端末等の電子機器、自動車等に多用されている。上記非水電解質二次電池は、一般的には、セパレータで電気的に隔離された一対の電極を有する電極体、及び電極間に介在する非水電解質を備え、両電極間でイオンの受け渡しを行うことで充放電するよう構成される。また、非水電解質二次電池以外の非水電解質蓄電素子として、リチウムイオンキャパシタや電気二重層キャパシタ等のキャパシタも広く普及している。 Non-aqueous electrolyte secondary batteries represented by lithium-ion non-aqueous electrolyte secondary batteries are widely used in personal computers, electronic devices such as communication terminals, automobiles, etc. due to their high energy density. The non-aqueous electrolyte secondary battery generally includes an electrode body having a pair of electrodes electrically separated by a separator, and a non-aqueous electrolyte interposed between the electrodes, and transfers ions between the two electrodes. It is configured to charge and discharge by doing. In addition, capacitors such as lithium ion capacitors and electric double layer capacitors are also widely used as non-aqueous electrolyte storage elements other than non-aqueous electrolyte secondary batteries.
　このような非水電解質蓄電素子の負極基材としては、銅箔が広く用いられている。一方、低コスト化、軽量化及び過放電時の集電体の溶出抑制の観点からは、アルミニウム箔の負極基材が好ましい。従来技術においては、アルミニウム箔の表面にカーボンコートを施した負極基材が提案されている（特許文献１参照）。 Copper foil is widely used as the negative electrode base material of such a non-aqueous electrolyte power storage element. On the other hand, from the viewpoint of cost reduction, weight reduction, and suppression of elution of the current collector during over-discharge, a negative electrode base material made of aluminum foil is preferable. In the prior art, a negative electrode base material in which the surface of an aluminum foil is coated with carbon has been proposed (see Patent Document 1).
特開２０１３－０３０３６２号公報Japanese Unexamined Patent Publication No. 2013-03562
　非水電解質蓄電素子は、用途に応じ、急速充電受け入れ性能が求められている。負極基材としてアルミニウム箔を使用した蓄電素子においては、リチウム－アルミニウム合金化反応が生じやすいことから、０．３５Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）程度以上の貴な電位で負極を作動させる必要がある。そのような電位で負極を作動させることにより、負極における金属リチウムのデンドライト状の析出を抑制できるため、急速充電が可能となる。 The non-aqueous electrolyte power storage element is required to have a quick charge acceptance performance depending on the application. In a power storage element using an aluminum foil as a negative electrode base material, a lithium-aluminum alloying reaction is likely to occur, so it is necessary to operate the negative electrode at a noble potential of about 0.35 V (vs. Li / Li + ) or higher. be. By operating the negative electrode at such a potential, dendrite-like precipitation of metallic lithium on the negative electrode can be suppressed, so that rapid charging becomes possible.
　しかしながら、黒鉛及び難黒鉛化性炭素（ハードカーボン）は、充電終止電位を０．４Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）とした場合、その充放電容量は８０ｍＡｈｇ－１以下であり、質量あたりの容量としては十分ではない。また、負極基材としてアルミニウム箔を適用可能な負極活物質として利用されているチタン酸リチウムは、作動電位は約１．５Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）と０．３５Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）よりも大幅に貴であるが、低容量、高電位、高コスト等の課題を有する。このため、アルミニウム箔を負極基材として適用可能な比較的貴な電位領域で作動する高容量負極活物質の開発が求められている。 However, the charge / discharge capacity of graphite and non-graphitizable carbon (hard carbon) is 80 mAhg -1 or less when the charge termination potential is 0.4 V (vs. Li / Li + ), and the capacity per mass. Not enough. Lithium titanate, which is used as a negative electrode active material to which an aluminum foil can be applied as a negative electrode base material, has an operating potential of about 1.5 V (vs. Li / Li + ) and 0.35 V (vs. Li / Li). Although it is significantly more noble than + ), it has problems such as low capacity, high potential, and high cost. Therefore, there is a demand for the development of a high-capacity negative electrode active material that operates in a relatively noble potential region in which an aluminum foil can be used as a negative electrode base material.
　本発明は、以上のような事情に基づいてなされたものであり、０．３５Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）程度以上の比較的貴な電位領域における質量あたりの放電容量及びクーロン効率を高めることができる非水電解質蓄電素子用負極活物質を提供することを目的とする。 The present invention has been made based on the above circumstances, and enhances the discharge capacity per mass and the Coulomb efficiency in a relatively noble potential region of about 0.35 V (vs. Li / Li + ) or more. It is an object of the present invention to provide a negative electrode active material for a non-aqueous electrolyte power storage element capable of producing a negative electrode.
　本発明の一側面に係る非水電解質蓄電素子用負極活物質は、ホウ素を含み、層状の結晶構造を有する炭素材料を含有し、下記式１で求められる上記炭素材料に含まれるホウ素－炭素結合を形成するホウ素の含有量が０．６質量％以上であり、上記炭素材料のラマン分光法によるスペクトルにおける１５００ｃｍ－１以上１７００ｃｍ－１以下の範囲での最大強度ＩＧに対する、１４００ｃｍ－１以上１５５０ｃｍ－１以下の範囲での最小強度ＩＶの比ＩＶ／ＩＧが０．５以上である。
　Ｘ＝Ａ×Ｄ／Ｅ　・・・１
　式１中、Ｘは、ホウ素－炭素結合を形成するホウ素の含有量（質量％）、Ａは、高周波誘導結合プラズマ発光分光分析法により求められる上記炭素材料に含有される全ホウ素の含有量（質量％）、Ｄは、エックス線光電子分光法によるスペクトルにおいて、２７２ｅＶ以上３００ｅＶ以下の範囲で最大強度を示すＣ１ｓのピーク位置を２８４．８ｅＶとしたときの、１８６ｅＶ以上１８８ｅＶ以下の範囲のＢ１ｓの積分強度、Ｅは、上記エックス線光電子分光法によるスペクトルにおける、１８６ｅＶ以上１９６ｅＶ以下の範囲のＢ１ｓの積分強度である。 The negative electrode active material for a non-aqueous electrolyte power storage element according to one aspect of the present invention contains boron and contains a carbon material having a layered crystal structure, and is a boron-carbon bond contained in the carbon material obtained by the following formula 1. The content of boron forming is 1400 cm -1 or more and 1550 cm with respect to the maximum intensity IG in the range of 1500 cm -1 or more and 1700 cm -1 or less in the spectrum of the above carbon material by Raman spectroscopy. The ratio IV / IG of the minimum intensity IV in the range of -1 or less is 0.5 or more.
X = A × D / E ・ ・ ・ 1
In formula 1, X is the content (% by mass) of boron forming a boron-carbon bond, and A is the content of total boron contained in the carbon material obtained by high frequency induced bond plasma emission spectroscopy (%). Mass%), D is the integrated intensity of B1s in the range of 186 eV or more and 188 eV or less when the peak position of C1s showing the maximum intensity in the range of 272 eV or more and 300 eV or less is 284.8 eV in the spectrum by X-ray photoelectron spectroscopy. , E are the integrated intensities of B1s in the range of 186 eV or more and 196 eV or less in the spectrum obtained by the X-ray photoelectron spectroscopy.
　本発明の他の一側面は、上記本発明の一側面に係る非水電解質蓄電素子用負極活物質を含有する非水電解質蓄電素子用負極である。 Another aspect of the present invention is a negative electrode for a non-aqueous electrolyte power storage element containing a negative electrode active material for a non-aqueous electrolyte power storage element according to the above aspect of the present invention.
　本発明の他の一側面は、上記本発明の一側面に係る非水電解質蓄電素子用負極を備える非水電解質蓄電素子である。 Another aspect of the present invention is the non-aqueous electrolyte power storage element provided with the negative electrode for the non-aqueous electrolyte power storage element according to the above aspect of the present invention.
　本発明の他の一側面は、非水電解質蓄電素子を二以上備え、且つ上記本発明の一側面に係る非水電解質蓄電素子を一以上備えた蓄電装置である。  Another aspect of the present invention is a power storage device provided with two or more non-aqueous electrolyte power storage elements and one or more non-water electrolyte power storage elements according to the above aspect of the present invention. The
　本発明によれば、０．３５Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）程度以上の比較的貴な電位領域における質量あたりの放電容量及びクーロン効率を高めることができる非水電解質蓄電素子用負極活物質を提供することができる。 According to the present invention, a negative electrode active material for a non-aqueous electrolyte power storage element capable of increasing the discharge capacity per mass and the Coulomb efficiency in a relatively noble potential region of about 0.35 V (vs. Li / Li + ) or more is provided. Can be provided.
図１は、非水電解質蓄電素子の一実施形態を示す透視斜視図である。FIG. 1 is a perspective perspective view showing an embodiment of a non-aqueous electrolyte power storage device. 図２は、非水電解質蓄電素子を複数個集合して構成した蓄電装置の一実施形態を示す概略図である。FIG. 2 is a schematic view showing an embodiment of a power storage device in which a plurality of non-aqueous electrolyte power storage elements are assembled.
　初めに、本明細書によって開示される非水電解質蓄電素子用負極活物質、非水電解質蓄電素子用負極、非水電解質蓄電素子及び蓄電装置の概要について説明する。 First, an outline of the negative electrode active material for a non-aqueous electrolyte storage element, the negative electrode for a non-aqueous electrolyte storage element, the non-aqueous electrolyte storage element, and the power storage device disclosed in the present specification will be described.
　本発明の一側面に係る非水電解質蓄電素子用負極活物質（以下、単に「負極活物質」ともいう。）は、ホウ素を含み、層状の結晶構造を有する炭素材料を含有し、下記式１で求められる上記炭素材料に含まれるホウ素－炭素結合を形成するホウ素の含有量が０．６質量％以上であり、上記炭素材料のラマン分光法によるスペクトルにおける１５００ｃｍ－１以上１７００ｃｍ－１以下の範囲での最大強度ＩＧに対する、１４００ｃｍ－１以上１５５０ｃｍ－１以下の範囲での最小強度ＩＶの比ＩＶ／ＩＧが０．５以上である。
　Ｘ＝Ａ×Ｄ／Ｅ　・・・１
　式１中、Ｘは、ホウ素－炭素結合を形成するホウ素の含有量（質量％）、Ａは、高周波誘導結合プラズマ発光分光分析法により求められる上記炭素材料に含有される全ホウ素の含有量（質量％）、Ｄは、エックス線光電子分光法によるスペクトルにおいて、２７２ｅＶ以上３００ｅＶ以下の範囲で最大強度を示すＣ１ｓのピーク位置を２８４．８ｅＶとしたときの、１８６ｅＶ以上１８８ｅＶ以下の範囲のＢ１ｓの積分強度、Ｅは、上記エックス線光電子分光法によるスペクトルにおける、１８６ｅＶ以上１９６ｅＶ以下の範囲のＢ１ｓの積分強度である。 The negative electrode active material for a non-aqueous electrolyte power storage device according to one aspect of the present invention (hereinafter, also simply referred to as “negative electrode active material”) contains a carbon material containing boron and having a layered crystal structure, and has the following formula 1 The content of boron forming a boron-carbon bond contained in the carbon material obtained in 1 above is 0.6% by mass or more, and the range of 1500 cm -1 or more and 1700 cm -1 or less in the spectrum of the carbon material by Raman spectroscopy. The ratio of the minimum intensity IV to the maximum intensity IG in the range of 1400 cm -1 or more and 1550 cm -1 or less is 0.5 or more.
X = A × D / E ・ ・ ・ 1
In formula 1, X is the content (% by mass) of boron forming a boron-carbon bond, and A is the content of total boron contained in the carbon material obtained by high frequency induced bond plasma emission spectroscopy (%). Mass%), D is the integrated intensity of B1s in the range of 186 eV or more and 188 eV or less when the peak position of C1s showing the maximum intensity in the range of 272 eV or more and 300 eV or less is 284.8 eV in the spectrum by X-ray photoelectron spectroscopy. , E are the integrated intensities of B1s in the range of 186 eV or more and 196 eV or less in the spectrum obtained by the X-ray photoelectron spectroscopy.
　当該負極活物質は、０．３５Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）程度以上の比較的貴な電位領域における質量あたりの放電容量及びクーロン効率を高めることができる。
　この理由については定かでは無いが、以下の理由が推測される。先行文献においては、第一原理計算の結果より、Ｂを含有した炭素材料ＢＣ３は、黒鉛よりも多くのリチウムイオンを吸蔵することができると報告されている（Ｊ．Ｐｈｙｓ．Ｃｈｅｍ．Ｌｅｔｔ．２０１３，４，１０，１７３７－１７４２．）。当該負極活物質のエックス線光電子分光法（ＸＰＳ：Ｘ－ｒａｙ　Ｐｈｏｔｏｅｌｅｃｔｒｏｎ　Ｓｐｅｃｔｒｏｓｃｏｐｙ）によるスペクトルにおいては、１８８ｅＶ付近にホウ素－炭素結合に由来するとみられるピークを有し、このピークはグラフェン層中の炭素に置換してドープされたホウ素に起因するものと推測される。そして、当該負極活物質における炭素材料に含まれるホウ素－炭素結合を形成するホウ素の含有量は、上記炭素材料に含まれるグラフェン層中の炭素に置換してドープされたホウ素の含有量を示す。上記炭素材料に含まれるホウ素－炭素結合を形成するホウ素の含有量が０．６質量％以上である当該負極活物質は、グラフェン層中の炭素に置換してドープされたホウ素の含有量が多いため、比較的貴な電位領域における質量あたりの放電容量及びクーロン効率が向上する。また、グラフェン層中にホウ素がドープされた炭素材料は、黒鉛化度が低く、上記比ＩＶ／ＩＧは高くなると推測される。そのため、グラフェン層中にホウ素がドープされ、上記比ＩＶ／ＩＧが０．５以上である当該負極活物質は、グラフェン層中の欠陥の減少及び当該負極活物質の可逆容量の増加が生じたことで、クーロン効率が高まったと推測される。その結果、当該負極活物質は、０．３５Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）程度以上の比較的貴な電位領域における質量あたりの放電容量及びクーロン効率を高めることができると考えられる。 The negative electrode active material can increase the discharge capacity per mass and the Coulomb efficiency in a relatively noble potential region of about 0.35 V (vs. Li / Li + ) or more.
The reason for this is not clear, but the following reasons are presumed. In the prior art, it has been reported from the results of first-principles calculations that the carbon material BC 3 containing B can occlude more lithium ions than graphite (J. Phys. Chem. Lett. 2013, 4, 10, 1737-1742.). In the spectrum of the negative electrode active material by X-ray photoelectron spectroscopy (XPS: X-ray Photoelectron Spectroscopy), a peak that seems to be derived from a boron-carbon bond is present near 188 eV, and this peak is replaced with carbon in the graphene layer. It is presumed that this is due to the boron doped in. The content of boron forming a boron-carbon bond contained in the carbon material in the negative electrode active material indicates the content of boron doped by substituting carbon in the graphene layer contained in the carbon material. The negative electrode active material having a boron-carbon bond-forming boron content of 0.6% by mass or more contained in the carbon material has a high content of boron doped by replacing carbon in the graphene layer. Therefore, the discharge capacity per mass and the Coulomb efficiency in a relatively noble potential region are improved. Further, it is presumed that the carbon material doped with boron in the graphene layer has a low graphitization degree and a high ratio IV / IG . Therefore, the negative electrode active material in which boron is doped in the graphene layer and the ratio IV / IG is 0.5 or more causes a decrease in defects in the graphene layer and an increase in the reversible capacity of the negative electrode active material. As a result, it is presumed that the Coulomb efficiency has increased. As a result, it is considered that the negative electrode active material can increase the discharge capacity per mass and the Coulomb efficiency in a relatively noble potential region of about 0.35 V (vs. Li / Li + ) or more.
　当該負極活物質においては、８００℃超の雰囲気温度下における酸素の脱離量が、上記炭素材料に対して２．４５質量％以下であることが好ましい。炭素材料は含酸素官能基を含むと高容量化するが、その充放電ヒステリシスは大きくなり、不可逆容量が増大するとともに、容量維持率が低下する傾向がある。例えば石英管を用いて化学気相成長法（Ｃｈｅｍｉｃａｌ　Ｖａｐｏｒ　Ｄｅｐｏｓｉｔｉｏｎ：ＣＶＤ）によってホウ素－炭素結合を有する炭素材料を合成した場合、上記合成されたホウ素－炭素結合を有する炭素材料はエッジ面が多く露出し、結晶構造の欠陥が多い。そのため、上記合成された炭素材料は、空気中で酸化されやすく、表面に含酸素官能基が形成される。その結果、ホウ素－炭素結合を有する炭素材料は、充放電ヒステリシスが大きくなると考えられる。従って、ホウ素－炭素結合を有する炭素材料においては、８００℃超で脱離する酸素の含有量が少ないほど含酸素官能基の含有量が少なく、充放電ヒステリシスは小さくなると推測される。従って、当該負極活物質においては、８００℃超の雰囲気温度下における酸素の脱離量が、上記炭素材料に対して２．４５質量％以下であることで、充放電ヒステリシスを小さくできる。また、充放電ヒステリシスが小さくなることで、クーロン効率を向上できる。なお、充放電ヒステリシスとは、充電時の平均閉回路電位と放電時の平均閉回路電位との差を示す。 In the negative electrode active material, the amount of oxygen desorbed at an atmospheric temperature of more than 800 ° C. is preferably 2.45% by mass or less with respect to the carbon material. When the carbon material contains an oxygen-containing functional group, the capacity increases, but the charge / discharge hysteresis becomes large, the irreversible capacity increases, and the capacity retention rate tends to decrease. For example, when a carbon material having a boron-carbon bond is synthesized by a chemical vapor deposition (CVD) using a quartz tube, the synthesized carbon material having a boron-carbon bond has many edge surfaces exposed. However, there are many defects in the crystal structure. Therefore, the synthesized carbon material is easily oxidized in the air, and an oxygen-containing functional group is formed on the surface. As a result, it is considered that the carbon material having a boron-carbon bond has a large charge / discharge hysteresis. Therefore, in a carbon material having a boron-carbon bond, it is presumed that the smaller the content of oxygen desorbed at more than 800 ° C., the smaller the content of oxygen-containing functional groups, and the smaller the charge / discharge hysteresis. Therefore, in the negative electrode active material, the amount of oxygen desorbed at an atmospheric temperature of more than 800 ° C. is 2.45% by mass or less with respect to the carbon material, so that the charge / discharge hysteresis can be reduced. In addition, the Coulomb efficiency can be improved by reducing the charge / discharge hysteresis. The charge / discharge hysteresis indicates the difference between the average closed circuit potential during charging and the average closed circuit potential during discharging.
　当該負極活物質においては、上記炭素材料の粒子径分布における平均粒径が、３．５６μｍ超７．６８μｍ未満であることが好ましい。当該負極活物質は、炭素材料の平均粒径が前記範囲であることで、比較的貴な電位領域における質量あたりの放電容量を特に高めることができる。 In the negative electrode active material, it is preferable that the average particle size in the particle size distribution of the carbon material is more than 3.56 μm and less than 7.68 μm. When the average particle size of the carbon material is in the above range, the negative electrode active material can particularly increase the discharge capacity per mass in a relatively noble potential region.
　当該負極活物質においては、ＣｕＫαを線源とする粉末エックス線回折パターンにおける、マニュアル手法による（００２）面回折ピークの半値全幅が１．７７°超であることが好ましい。当該負極活物質は、（００２）面回折ピークの半値全幅が１．７７超であることで、比較的貴な電位領域における放電容量を良好な範囲に維持することができ、また、比較的卑な放電電位を示すことができる。 In the negative electrode active material, it is preferable that the full width at half maximum of the (002) plane diffraction peak by the manual method in the powder X-ray diffraction pattern using CuKα as a radiation source is more than 1.77 °. Since the full width at half maximum of the (002) plane diffraction peak of the negative electrode active material is more than 1.77, the discharge capacity in a relatively noble potential region can be maintained in a good range, and the discharge capacity is relatively low. Can show a good discharge potential.
　本発明の一側面に係る非水電解質蓄電素子用負極（以下、単に「負極」ともいう。）は、当該負極活物質を含有する。当該負極は、当該負極活物質を含有するので、０．３５Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）程度以上の比較的貴な電位領域における質量あたりの放電容量及びクーロン効率を高めることができる。 The negative electrode for a non-aqueous electrolyte power storage element (hereinafter, also simply referred to as “negative electrode”) according to one aspect of the present invention contains the negative electrode active material. Since the negative electrode contains the negative electrode active material, it is possible to increase the discharge capacity per mass and the Coulomb efficiency in a relatively noble potential region of about 0.35 V (vs. Li / Li + ) or more.
　当該負極はカーボンナノチューブをさらに含有することが好ましい。当該負極はカーボンナノチューブをさらに含有することで、過充電時におけるクーロン効率を向上できる。この理由については定かでは無いが、以下の理由が推測される。ホウ素－炭素結合を有する炭素材料は、充放電に伴い体積の膨張収縮が起きるため、負極活物質の電子伝導経路からの孤立化が起きやすい傾向がある。しかしながら、負極がカーボンナノチューブを含有した場合、カーボンナノチューブにより負極活物質層中の電子伝導経路のネットワークが維持され、孤立化する負極活物質が減少すると考えられる。従って、当該負極はカーボンナノチューブをさらに含有することで、過充電時におけるクーロン効率を向上できる。 It is preferable that the negative electrode further contains carbon nanotubes. By further containing carbon nanotubes in the negative electrode, the coulombic efficiency at the time of overcharging can be improved. The reason for this is not clear, but the following reasons are presumed. A carbon material having a boron-carbon bond tends to be isolated from the electron conduction path of the negative electrode active material because the volume of the carbon material expands and contracts with charge and discharge. However, when the negative electrode contains carbon nanotubes, it is considered that the carbon nanotubes maintain the network of electron conduction paths in the negative electrode active material layer and reduce the amount of isolated negative electrode active material. Therefore, the negative electrode further contains carbon nanotubes, so that the coulombic efficiency at the time of overcharging can be improved.
　当該負極の作動電位は０．０１Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）以上とすることができ、負極の作動電位が０．３５Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）以上となる場合には、当該非水電解質蓄電素子用負極は純アルミニウム又はアルミニウム合金からなる負極基材をさらに有することが好ましい。当該非水電解質蓄電素子用負極は純アルミニウム又はアルミニウム合金からなる負極基材をさらに有することで、低コスト化及び軽量化を図ることができる。 The working potential of the negative electrode can be 0.01 V (vs. Li / Li + ) or more, and when the working potential of the negative electrode is 0.35 V (vs. Li / Li + ) or more, the non-water It is preferable that the negative electrode for the electrolyte storage element further has a negative electrode base material made of pure aluminum or an aluminum alloy. The negative electrode for the non-aqueous electrolyte power storage element further has a negative electrode base material made of pure aluminum or an aluminum alloy, so that cost reduction and weight reduction can be achieved.
　本発明の一側面に係る非水電解質蓄電素子は、当該負極を備える。当該非水電解質蓄電素子は、当該負極を備えるので、０．３５Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）程度以上の比較的貴な電位領域における質量あたりの放電容量及びクーロン効率を高めることができる。 The non-aqueous electrolyte power storage element according to one aspect of the present invention includes the negative electrode. Since the non-aqueous electrolyte power storage element includes the negative electrode, it is possible to increase the discharge capacity per mass and the Coulomb efficiency in a relatively noble potential region of about 0.35 V (vs. Li / Li + ) or more.
　当該非水電解質蓄電素子は、通常使用時の充電終止電圧における負極電位が、０．３５Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）以上が好ましい。当該非水電解質蓄電素子は、通常使用時において上記負極電位が０．３５Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）以上となるように充電を行うことで、負極における金属リチウムのデンドライト状の析出を抑制できるため、急速充電が可能となる。また、負極が純アルミニウム又はアルミニウム合金からなる負極基材を有する場合には、リチウム－アルミニウム合金化反応が生じることによる蓄電素子性能の低下を抑制することができる。ここで、通常使用時とは、当該非水電解質蓄電素子について推奨され、又は指定される充放電条件を採用して当該非水電解質蓄電素子を使用する場合であり、当該非水電解質蓄電素子のための充電器が用意されている場合は、その充電器を適用して当該非水電解質蓄電素子を使用する場合をいう。また、本明細書において、炭素材料は負極活物質として作用するものであり、非水電解質から負極活物質に充放電反応に関与するイオン（リチウムイオン非水電解質二次電池の場合はリチウムイオン）が吸蔵される還元反応を「充電」、負極活物質から非水電解質に充放電反応に関与するイオンが放出される酸化反応を「放電」という。 The non-aqueous electrolyte power storage element preferably has a negative electrode potential of 0.35 V (vs. Li / Li + ) or more at the end-of-charge voltage during normal use. The non-aqueous electrolyte power storage element can be charged so that the negative electrode potential is 0.35 V (vs. Li / Li + ) or more during normal use, thereby suppressing the precipitation of metallic lithium in the negative electrode in the form of dendrite. Therefore, quick charging is possible. Further, when the negative electrode has a negative electrode base material made of pure aluminum or an aluminum alloy, deterioration of the power storage element performance due to the lithium-aluminum alloying reaction can be suppressed. Here, the normal use is a case where the non-aqueous electrolyte storage element is used by adopting the charge / discharge conditions recommended or specified for the non-aqueous electrolyte storage element, and the non-aqueous electrolyte power storage element is used. When a charger for this purpose is prepared, it means a case where the charger is applied to use the non-aqueous electrolyte power storage element. Further, in the present specification, the carbon material acts as a negative electrode active material, and ions involved in the charge / discharge reaction from the non-aqueous electrolyte to the negative electrode active material (lithium ions in the case of a lithium ion non-aqueous electrolyte secondary battery). The reduction reaction in which the water is stored is called "charging", and the oxidation reaction in which the ions involved in the charge / discharge reaction are released from the negative electrode active material to the non-aqueous electrolyte is called "discharge".
　当該非水電解質蓄電素子は、非水溶媒としてプロピレンカーボネートを含有する非水電解液を備えることが好ましい。当該非水電解質蓄電素子は、非水溶媒としてプロピレンカーボネートを含有することで、優れた高率充電電気量比を示すことができる。 The non-aqueous electrolyte storage element preferably includes a non-aqueous electrolytic solution containing propylene carbonate as a non-aqueous solvent. The non-aqueous electrolyte power storage element contains propylene carbonate as a non-aqueous solvent, so that it can exhibit an excellent high rate charge electricity amount ratio.
　当該非水電解質蓄電素子は、非水溶媒としてジエチルカーボネートを含有する非水電解液を備えることが好ましい。当該非水電解質蓄電素子は、非水溶媒としてジエチルカーボネートを含有することで、優れた高率充電電気量比を示すことができる。 The non-aqueous electrolyte storage element preferably includes a non-aqueous electrolytic solution containing diethyl carbonate as a non-aqueous solvent. The non-aqueous electrolyte power storage element contains diethyl carbonate as a non-aqueous solvent, so that it can exhibit an excellent high rate charge electricity quantity ratio.
　本発明の他の一側面は、非水電解質蓄電素子を二以上備え、且つ上記本発明の一側面に係る非水電解質蓄電素子を一以上備えた蓄電装置である。当該蓄電装置は、当該非水電解質蓄電素子を一以上備えるので、比較的貴な電位領域における質量あたりの放電容量及びクーロン効率を高めることができる。　 Another aspect of the present invention is a power storage device provided with two or more non-aqueous electrolyte power storage elements and one or more non-water electrolyte power storage elements according to the above aspect of the present invention. Since the power storage device includes one or more non-aqueous electrolyte power storage elements, it is possible to increase the discharge capacity per mass and the Coulomb efficiency in a relatively noble potential region. It was
　本発明の一実施形態に係る非水電解質蓄電素子用負極活物質の構成、非水電解質蓄電素子用負極活物質の製造方法、非水電解質蓄電素子用負極の構成、非水電解質蓄電素子の構成、非水電解質蓄電装置の構成、及び非水電解質蓄電素子の製造方法、並びにその他の実施形態について詳述する。なお、各実施形態に用いられる各構成部材（各構成要素）の名称は、背景技術に用いられる各構成部材（各構成要素）の名称と異なる場合がある。 Configuration of negative electrode active material for non-aqueous electrolyte power storage element, method for manufacturing negative electrode active material for non-aqueous electrolyte power storage element, configuration of negative electrode for non-aqueous electrolyte power storage element, configuration of non-aqueous electrolyte power storage element according to one embodiment of the present invention. , The configuration of the non-aqueous electrolyte power storage device, the method for manufacturing the non-water electrolyte power storage element, and other embodiments will be described in detail. The name of each component (each component) used in each embodiment may be different from the name of each component (each component) used in the background technique.
＜非水電解質蓄電素子用負極活物質＞
　本発明の一実施形態に係る非水電解質蓄電素子用負極活物質は、ホウ素を含み、層状の結晶構造を有する炭素材料を含有する。 <Negative electrode active material for non-aqueous electrolyte power storage element>
The negative electrode active material for a non-aqueous electrolyte power storage element according to an embodiment of the present invention contains boron and contains a carbon material having a layered crystal structure.
　上記負極活物質は、層状の結晶構造を有する炭素材料を含有する。負極活物質として炭素材料を含有することで、非水電解質蓄電素子のエネルギー密度を高めることができる。層状の結晶構造を有する炭素材料としては、例えば黒鉛、非黒鉛質炭素（難黒鉛化性炭素又は易黒鉛化性炭素）等が挙げられる。負極活物質としては、これら材料の１種を単独で用いてもよく、２種以上を混合して用いてもよい。 The negative electrode active material contains a carbon material having a layered crystal structure. By containing a carbon material as the negative electrode active material, the energy density of the non-aqueous electrolyte power storage element can be increased. Examples of the carbon material having a layered crystal structure include graphite, non-graphitizable carbon (non-graphitizable carbon or easily graphitizable carbon) and the like. As the negative electrode active material, one of these materials may be used alone, or two or more of them may be mixed and used.
　「黒鉛」とは、充放電前又は放電状態において、エックス線回折法により決定される（００２）面の平均格子面間隔（ｄ００２）が０．３３ｎｍ以上０．３４ｎｍ未満の炭素材料をいう。黒鉛としては、天然黒鉛、人造黒鉛が挙げられる。安定した物性の材料を入手できるという観点で、人造黒鉛が好ましい。 “Graphite” refers to a carbon material having an average lattice spacing (d 002 ) of (002) planes determined by X-ray diffraction method before charging / discharging or in a discharged state of 0.33 nm or more and less than 0.34 nm. Examples of graphite include natural graphite and artificial graphite. Artificial graphite is preferable from the viewpoint that a material having stable physical properties can be obtained.
　「非黒鉛質炭素」とは、充放電前又は放電状態においてエックス線回折法により決定される（００２）面の平均格子面間隔（ｄ００２）が０．３４ｎｍ以上０．４２ｎｍ以下の炭素材料をいう。非黒鉛質炭素としては、難黒鉛化性炭素や、易黒鉛化性炭素が挙げられる。非黒鉛質炭素としては、例えば、樹脂由来の材料、石油ピッチまたは石油ピッチ由来の材料、石油コークスまたは石油コークス由来の材料、植物由来の材料、アルコール由来の材料等が挙げられる。 "Non-graphitic carbon" refers to a carbon material having an average lattice spacing (d 002 ) of the (002) plane determined by the X-ray diffraction method before charging / discharging or in a discharged state of 0.34 nm or more and 0.42 nm or less. .. Examples of non-graphitizable carbon include non-graphitizable carbon and easily graphitizable carbon. Examples of the non-planar carbon include a resin-derived material, a petroleum pitch or a petroleum pitch-derived material, a petroleum coke or a petroleum coke-derived material, a plant-derived material, an alcohol-derived material, and the like.
　「難黒鉛化性炭素」とは、上記ｄ００２が０．３６ｎｍ以上０．４２ｎｍ以下の炭素材料をいう。 The “non-graphitizable carbon” refers to a carbon material having d 002 of 0.36 nm or more and 0.42 nm or less.
　「易黒鉛化性炭素」とは、上記ｄ００２が０．３４ｎｍ以上０．３６ｎｍ未満の炭素材料をいう。 The “graphitizable carbon” refers to a carbon material having d 002 of 0.34 nm or more and less than 0.36 nm.
　ここで、上記黒鉛及び非黒鉛質炭素の定義における「放電状態」とは、負極活物質である炭素材料から、充放電に伴い吸蔵放出可能な充放電反応に関与するイオンが十分に放出されるように放電された状態を意味する。例えば、負極活物質として炭素材料を含む負極を作用極として、金属リチウムを対極として用いた単極電池において、開回路電圧が２．０Ｖ以上である状態である。 Here, the "discharged state" in the definition of graphite and non-graphical carbon means that the carbon material, which is the negative electrode active material, sufficiently releases ions involved in the charge / discharge reaction that can be occluded and discharged during charge / discharge. It means the state of being discharged as such. For example, in a unipolar battery using a negative electrode containing a carbon material as a negative electrode active material as a working electrode and metallic lithium as a counter electrode, the open circuit voltage is 2.0 V or more.
　負極活物質は、通常、粒子（粉体）である。負極活物質が炭素材料である場合、その平均粒径は、１μｍ以上１００μｍ以下であってもよい。負極活物質の平均粒径を上記下限以上とすることで、負極活物質の製造又は取り扱いが容易になる。負極活物質の平均粒径を上記上限以下とすることで、活物質層の電子伝導性が向上する。「平均粒径」とは、ＪＩＳ－Ｚ－８８２５（２０１３年）に準拠し、粒子を溶媒で希釈した希釈液に対しレーザ回折・散乱法により測定した粒子径分布に基づき、ＪＩＳ－Ｚ－８８１９－２（２００１年）に準拠し計算される体積基準積算分布が５０％となる値を意味する。 The negative electrode active material is usually particles (powder). When the negative electrode active material is a carbon material, the average particle size thereof may be 1 μm or more and 100 μm or less. By setting the average particle size of the negative electrode active material to be equal to or higher than the above lower limit, the production or handling of the negative electrode active material becomes easy. By setting the average particle size of the negative electrode active material to the above upper limit or less, the electron conductivity of the active material layer is improved. The "average particle size" is based on JIS-Z-8825 (2013), and is based on the particle size distribution measured by the laser diffraction / scattering method for a diluted solution obtained by diluting the particles with a solvent. -2 (2001) means a value at which the volume-based integrated distribution calculated in accordance with (2001) is 50%.
　上記炭素材料の粒子径分布における平均粒径は２．０μｍ以上１０．０μｍ以下が好ましく、２．５μｍ以上９．０μｍ以下がより好ましく、３．０μｍ以上８．０μｍ以下がさらに好ましく、３．５６μｍ超７．６８μｍ未満がよりさらに好ましく、３．６μｍ以上７．０μｍ以下が一層好ましく、４．０μｍ以上６．０μｍ以下がより一層好ましい。炭素材料の平均粒径を前記範囲とすることで、比較的貴な電位領域における質量あたりの放電容量を特に高めることができる。 The average particle size in the particle size distribution of the carbon material is preferably 2.0 μm or more and 10.0 μm or less, more preferably 2.5 μm or more and 9.0 μm or less, further preferably 3.0 μm or more and 8.0 μm or less, and 3.56 μm. The ultra-less than 7.68 μm is even more preferable, 3.6 μm or more and 7.0 μm or less is further preferable, and 4.0 μm or more and 6.0 μm or less is even more preferable. By setting the average particle size of the carbon material in the above range, the discharge capacity per mass in a relatively noble potential region can be particularly increased.
　粉体を所定の粒径で得るためには粉砕機や分級機等が用いられる。粉砕方法として、例えば、乳鉢、ボールミル、サンドミル、振動ボールミル、遊星ボールミル、ジェットミル、カウンタージェットミル、旋回気流型ジェットミル又は篩等を用いる方法が挙げられる。粉砕時には水、あるいはヘキサン等の有機溶剤を共存させた湿式粉砕を用いることもできる。分級方法としては、篩や風力分級機等が、乾式、湿式ともに必要に応じて用いられる。 A crusher, a classifier, etc. are used to obtain powder with a predetermined particle size. Examples of the crushing method include a method using a mortar, a ball mill, a sand mill, a vibrating ball mill, a planetary ball mill, a jet mill, a counter jet mill, a swirling air flow type jet mill, a sieve, or the like. At the time of pulverization, wet pulverization in which water or an organic solvent such as hexane coexists can also be used. As a classification method, a sieve, a wind power classifier, or the like is used as needed for both dry type and wet type.
　上記炭素材料の全ホウ素の含有量Ａの下限としては、３．３質量％が好ましく、４．８質量％がより好ましい。上記炭素材料の全ホウ素の含有量Ａの下限が上記以上であることで、ホウ素－炭素結合を形成するホウ素の含有量が増加し、放電容量が高まる傾向にある。一方、上記炭素材料の全ホウ素の含有量Ａの上限としては、２２．０質量％が好ましい。上記炭素材料の全ホウ素の含有量Ａの上限が上記以下であることで、容量維持率の低下を抑制できる。これは、高容量化による充放電に伴う負極活物質の体積変化率の増加及び上記炭素材料の表面から溶出されるホウ素由来の被膜形成による抵抗の増加が抑制されることによると考えられる。また、上記炭素材料の全ホウ素の含有量Ａの上限が上記以下であることで、負極活物質の合成を確実に行うことができる。なお、上記炭素材料の全ホウ素の含有量Ａは高周波誘導結合プラズマ発光分光分析法（ＩＣＰ）により求められる。上記ＩＣＰの測定に用いる試料は、下記エックス線光電子分光法による負極活物質のスペクトルの測定に用いる試料と同様のものを準備する。 The lower limit of the total boron content A of the carbon material is preferably 3.3% by mass, more preferably 4.8% by mass. When the lower limit of the total boron content A of the carbon material is at least the above, the content of boron forming a boron-carbon bond tends to increase, and the discharge capacity tends to increase. On the other hand, the upper limit of the total boron content A of the carbon material is preferably 22.0% by mass. When the upper limit of the total boron content A of the carbon material is not more than the above, the decrease in the capacity retention rate can be suppressed. It is considered that this is because the increase in the volume change rate of the negative electrode active material due to charging and discharging due to the increase in capacity and the increase in resistance due to the formation of the boron-derived film eluted from the surface of the carbon material are suppressed. Further, when the upper limit of the total boron content A of the carbon material is not more than the above, the negative electrode active material can be reliably synthesized. The total boron content A of the carbon material is determined by high frequency inductively coupled plasma emission spectroscopy (ICP). As the sample used for the measurement of the ICP, the same sample as the sample used for the measurement of the spectrum of the negative electrode active material by the following X-ray photoelectron spectroscopy is prepared.
（エックス線光電子分光法によるスペクトル及び積分強度の測定）
　エックス線光電子分光法による負極活物質のスペクトルの測定に用いる試料は、当該負極活物質を合成し、乳鉢粉砕後のものを準備する。なお、上記試料は、合成後、再熱処理を行うことが好ましい。
　また、充放電後の非水電解質蓄電素子から試料を準備する場合は、０．１Ｃの電流で、通常使用時の放電終止電圧まで放電し、完全放電状態とする。完全放電状態の蓄電素子を解体して負極を取り出し、作用極を上記負極とし、対極を金属リチウムとした試験電池を作製する。この試験電池を、電流密度５０ｍＡｇ－１（負極活物質１ｇ当たり）で３．０Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）まで放電し、再度解体して、負極を取り出し、ジメチルカーボネートを用いて充分に洗浄する。その後、ＳＥＩ（ｓｏｌｉｄ　ｅｌｅｃｔｒｏｌｙｔｅ　ｉｎｔｅｒｆａｃｅ）被膜を除去するために、負極を通常雰囲気の大気中にて、所定の温度の水、酸、アルカリ、有機溶媒等の溶液中に２時間浸漬する。浸漬後に、負極を、水及びエタノールで洗浄し、減圧乾燥する（水系バインダの場合、脱落した負極活物質層を減圧濾過により回収した後に乾燥する）。なお、上記浸漬処理を行わずに、熱処理によりＳＥＩ被膜を除去してもよい。次に、負極を、所定サイズ（例えば２ｃｍ×２ｃｍ）に切り出し（水系バインダの場合、回収した負極活物質層を）、ＸＰＳスペクトル測定における試料とすることができる。電池の解体作業は、露点－６０℃以下のアルゴン雰囲気中で行う。
　次に、試料ホルダー上にカーボンテープを貼り、そこへ試料を載せる。試料ホルダーをＸＰＳ装置であるＫＲＡＴＯＳ　ＡＮＡＬＹＴＩＣＡＬ社製の「ＡＸＩＳ　ＮＯＶＡ」の試料室内に導入し、ＸＰＳスペクトルを取得する。ＸＰＳ測定は真空度５×１０－５Ｐａ以下の減圧下で行う。Ｃ１ｓ及びＢ１ｓスペクトルを測定するため、それぞれ２７２ｅＶから３００ｅＶ、及び１８１ｅＶから２０１ｅＶにて、１０回積算でナロースキャンを行う。得られたＣ１ｓスペクトルから、Ｃ１ｓピークの最大の強度を示すエネルギー値を２８４．８ｅＶとなるように、Ｂ１ｓ及びＣ１ｓスペクトルのエネルギー値を補正する。なお、この補正に用いるＣ１ｓピークは、Ｃ－Ｃ及び（または）Ｃ＝Ｃ結合に由来するとみられる。
　エックス線源としてはＡｌＫαを用い、Ｅｍｉｓｓｉｏｎを１０ｍＡ、Ａｎｏｄｅ　ＨＴを１５ｋＶとする。測定時には、中和銃を用い、そのＦｉｌａｍｅｎｔ　ｃｕｒｒｅｎｔを２Ａ、Ｃｈａｒｇｅ　Ｂａｌａｎｃｅを３．５Ｖ、Ｆｉｌａｍｅｎｔ　Ｂｉａｓを１．２Ｖとする。ナロースキャン時の条件として、ステップサイズ０．１ｅＶ、ドウェル時間を２５０ｍｓとする。また、アナライザの条件として、アナライザモードを「Ｓｐｅｃｔｒｕｍ」、レンズモードを「Ｆｉｅｌｄ　ｏｆ　Ｖｉｅｗ　１：　Ｓｕｒｖｅｙ」、エネルギー分解能を「Ｐａｓｓ　Ｅｎｅｒｇｙ　４０」、分析エリアを「ｓｌｏｔ」とする。 (Measurement of spectrum and integrated intensity by X-ray photoelectron spectroscopy)
As the sample used for measuring the spectrum of the negative electrode active material by X-ray photoelectron spectroscopy, the negative electrode active material is synthesized and prepared after crushing the mortar. It is preferable that the above sample is reheat-treated after synthesis.
When the sample is prepared from the non-aqueous electrolyte storage element after charging and discharging, the sample is discharged to the discharge end voltage at the time of normal use with a current of 0.1 C to bring it into a completely discharged state. A test battery is manufactured by disassembling the power storage element in a completely discharged state, taking out the negative electrode, using the negative electrode as the working electrode, and using metallic lithium as the counter electrode. This test battery is discharged to 3.0 V (vs. Li / Li + ) at a current density of 50 mAg -1 (per 1 g of negative electrode active material), disassembled again, the negative electrode is taken out, and thoroughly washed with dimethyl carbonate. do. Then, in order to remove the SEI (solid-electrolyte interface) film, the negative electrode is immersed in a solution of water, acid, alkali, organic solvent or the like at a predetermined temperature in an atmosphere of a normal atmosphere for 2 hours. After the immersion, the negative electrode is washed with water and ethanol and dried under reduced pressure (in the case of an aqueous binder, the dropped negative electrode active material layer is recovered by vacuum filtration and then dried). The SEI film may be removed by heat treatment without performing the dipping treatment. Next, the negative electrode can be cut out to a predetermined size (for example, 2 cm × 2 cm) (in the case of an aqueous binder, the recovered negative electrode active material layer) and used as a sample for XPS spectrum measurement. The battery disassembly work is performed in an argon atmosphere with a dew point of −60 ° C. or lower.
Next, a carbon tape is attached on the sample holder, and the sample is placed there. The sample holder is introduced into the sample chamber of "AXIS NOVA" manufactured by KRATOS ANALYTICAL, which is an XPS device, and the XPS spectrum is acquired. XPS measurement is performed under a reduced pressure of vacuum degree 5 × 10 -5 Pa or less. In order to measure the C1s and B1s spectra, narrow scans are performed 10 times at 272 eV to 300 eV and 181 eV to 201 eV, respectively. From the obtained C1s spectrum, the energy values of the B1s and C1s spectra are corrected so that the energy value indicating the maximum intensity of the C1s peak is 284.8 eV. The C1s peak used for this correction seems to be derived from CC and / or C = C bonds.
AlKα is used as an X-ray source, the Emission is 10 mA, and the Anode HT is 15 kV. At the time of measurement, a neutralization gun is used, and the Filment current is set to 2A, the Charge Balance is set to 3.5V, and the Filment Bias is set to 1.2V. The conditions for narrow scan are a step size of 0.1 eV and a dwell time of 250 ms. As the conditions of the analyzer, the analyzer mode is "Spectrum", the lens mode is "Field of View 1: Survey", the energy resolution is "Pass Energy 40", and the analysis area is "slot".
　上記方法により、エネルギー値を補正したＢ１ｓスペクトルについて、１８２ｅＶから１８６ｅＶにおいて最小の強度を示す点と、１９６ｅＶから２００ｅＶにおいて、最小の強度を示す点を結んだ一次関数をバックグラウンドとして除去する。バックグラウンドを除去したＢ１ｓスペクトルについて、１８６ｅＶ以上１９６ｅＶ以下の範囲のＢ１ｓの積分強度Ｅに対する、１８６ｅＶ以上１８８ｅＶ以下の範囲のＢ１ｓの積分強度Ｄの比を、積分強度比Ｄ／Ｅとする。上記積分強度比Ｄ／Ｅは、上記炭素材料に含まれる全ホウ素に対するグラフェン層中の炭素に置換してドープされた（ホウ素－炭素結合を形成した）ホウ素のモル比を表す。なお、実際には、ホウ素－炭素結合由来のピークは、１８８ｅＶより高エネルギー側にまですそを引くが、ホウ素単体やホウ素－窒素結合由来のピークも検出された場合に、それらのピークの影響を小さくするため、積分強度を求める範囲の上限を１８８ｅＶに設定している。 By the above method, the linear function connecting the points showing the minimum intensity from 182 eV to 186 eV and the points showing the minimum intensity from 196 eV to 200 eV is removed from the B1s spectrum corrected by the energy value as the background. With respect to the B1s spectrum from which the background has been removed, the ratio of the integrated intensity D of B1s in the range of 186 eV or more and 188 eV or less to the integrated intensity E of B1s in the range of 186 eV or more and 196 eV or less is defined as the integrated intensity ratio D / E. The integrated intensity ratio D / E represents the molar ratio of boron doped (forming a boron-carbon bond) by substituting carbon in the graphene layer with respect to the total boron contained in the carbon material. In reality, the peaks derived from the boron-carbon bond are drawn to the higher energy side than 188 eV, but when the peaks derived from elemental boron or the boron-nitrogen bond are also detected, the influence of those peaks is affected. In order to reduce the value, the upper limit of the range for obtaining the integrated strength is set to 188 eV.
　上記エックス線光電子分光法による積分強度比Ｄ／Ｅの下限としては、０．１５４が好ましく、０．１７６がより好ましい。上記積分強度比Ｄ／Ｅの下限が上記以上であることで、比較的貴な電位領域におけるクーロン効率を高めることができる。積分強度比Ｄ／Ｅの上限としては、０．３９０が好ましく、０．３８０がより好ましい。上記積分強度比Ｄ／Ｅの上限が上記以下であることで、耐久性との両立ができる。 As the lower limit of the integrated intensity ratio D / E by the X-ray photoelectron spectroscopy, 0.154 is preferable, and 0.176 is more preferable. When the lower limit of the integrated intensity ratio D / E is equal to or higher than the above, the Coulomb efficiency in a relatively noble potential region can be increased. As the upper limit of the integrated intensity ratio D / E, 0.390 is preferable, and 0.380 is more preferable. When the upper limit of the integrated strength ratio D / E is not more than the above, both durability can be achieved.
　上記炭素材料に含まれるホウ素－炭素結合を形成するホウ素の含有量、すなわち、上記炭素材料に含まれるグラフェン層中の炭素に置換してドープされたホウ素の含有量、すなわち、グラフェン層においてホウ素－炭素結合を形成したホウ素の含有量の下限としては、０．６質量％が好ましく、１．４質量％がより好ましい。上記炭素材料に含まれるホウ素－炭素結合を形成するホウ素の含有量の下限が上記以上であることで、比較的貴な電位領域における質量あたりの放電容量及びクーロン効率を高めることができる。一方、上記炭素材料に含まれるホウ素－炭素結合を形成するホウ素の含有量の上限としては、８．０質量％が好ましい。上記炭素材料に含まれるホウ素－炭素結合を形成するホウ素の含有量の上限が上記以下であることで、負極活物質の合成を確実に行うことができる。上記炭素材料に含まれるホウ素－炭素結合を形成するホウ素の含有量は、上記式１により算出することができる。 The content of boron contained in the carbon material to form a carbon bond, that is, the content of boron substituted with carbon in the graphene layer contained in the carbon material, that is, boron in the graphene layer. The lower limit of the content of boron forming a carbon bond is preferably 0.6% by mass, more preferably 1.4% by mass. When the lower limit of the content of boron forming a boron-carbon bond contained in the carbon material is at least the above, the discharge capacity per mass and the Coulomb efficiency in a relatively noble potential region can be increased. On the other hand, the upper limit of the content of boron that forms a boron-carbon bond contained in the carbon material is preferably 8.0% by mass. When the upper limit of the content of boron that forms a boron-carbon bond contained in the carbon material is not more than the above, the negative electrode active material can be reliably synthesized. The content of boron that forms a boron-carbon bond contained in the carbon material can be calculated by the above formula 1.
　上記炭素材料のラマン分光法によるスペクトルにおける１５００ｃｍ－１以上１７００ｃｍ－１以下の範囲での最大強度ＩＧに対する、１４００ｃｍ－１以上１５５０ｃｍ－１以下の範囲での最小強度ＩＶの比ＩＶ／ＩＧの下限としては、０．５０であり、０．５３が好ましい。一方、上記ＩＶ／ＩＧの上限としては、０．９０が好ましい。上記ＩＶ／ＩＧを上記範囲とすることで、比較的貴な電位領域におけるクーロン効率を高めることができる。 The ratio of the minimum intensity IV in the range of 1400 cm -1 or more and 1550 cm -1 or less to the maximum intensity IG in the range of 1500 cm -1 or more and 1700 cm -1 or less in the spectrum of the carbon material by Raman spectroscopy IV / I. The lower limit of G is 0.50, preferably 0.53. On the other hand, the upper limit of the above IV / IG is preferably 0.90. By setting the above IV / IG in the above range, the Coulomb efficiency in a relatively noble potential region can be increased.
（ラマン分光法によるスペクトルの測定）
　「ラマン分光法によるスペクトル（ラマンスペクトル）」は、ＨＯＲＩＢＡ社製の顕微レーザーラマン分光測定装置「ＬａｂＲａｍ　ＨＲ　Ｅｖｏｌｕｔｉｏｎ」を用いて取得する。レーザ波長は５３２ｎｍ、露光時間３０秒、積算２回、波数範囲１００ｃｍ－１から４０００ｃｍ－１として測定する。得られたラマンスペクトルについて、８００ｃｍ－１から１３００ｃｍ－１において最小値を示す点と、１７００ｃｍ－１から２０００ｃｍ－１において最小値を示す点とを通る一次関数を、バックグラウンドとして除去する。バックグラウンドを除去したラマンスペクトルについて、１５００ｃｍ－１以上１７００ｃｍ－１以下の範囲での最大強度をＩＧとし、１４００ｃｍ－１以上１５５０ｃｍ－１以下の範囲での最小強度をＩＶとして、ＩＶ／ＩＧを算出する。 (Measurement of spectrum by Raman spectroscopy)
The "spectrum by Raman spectroscopy (Raman spectrum)" is acquired by using a microlaser Raman spectroscopy measuring device "LabRam HR Evolution" manufactured by HORIBA. The laser wavelength is 532 nm, the exposure time is 30 seconds, the integration is twice, and the wave number range is 100 cm -1 to 4000 cm -1 . For the obtained Raman spectrum, the linear function passing through the point showing the minimum value from 800 cm -1 to 1300 cm -1 and the point showing the minimum value from 1700 cm -1 to 2000 cm -1 is removed as the background. For the Raman spectrum with the background removed, the maximum intensity in the range of 1500 cm -1 or more and 1700 cm -1 or less is defined as IG , and the minimum intensity in the range of 1400 cm -1 or more and 1550 cm -1 or less is defined as IV . Calculate IG .
　当該非水電解質蓄電素子用負極活物質が含有する炭素材料のＣｕＫα線を用いたエックス線回折における（１０）面回折ピーク位置としては、２θ＝４２．５°以下が好ましい。上記エックス線回折における（１０）面回折ピーク位置が、上記上限以下であることで、比較的貴な電位領域における放電容量を良好な範囲に維持することができる。 The (10) plane diffraction peak position in X-ray diffraction using CuKα ray of the carbon material contained in the negative electrode active material for the non-aqueous electrolyte power storage element is preferably 2θ = 42.5 ° or less. When the (10) plane diffraction peak position in the X-ray diffraction is not more than the upper limit, the discharge capacity in a relatively noble potential region can be maintained in a good range.
　当該非水電解質蓄電素子用負極活物質が含有する炭素材料のＣｕＫα線を用いたエックス線回折におけるマニュアル手法による（００２）面回折ピークの半値全幅の下限としては、０．５°以上が好ましく、１．０°がより好ましく、１．５°以上がさらに好ましく、１．７７超がよりさらに好ましい。上記（００２）面回折ピークの半値全幅の上限としては５．０°以下が好ましい。上記（００２）面回折ピークの半値全幅が上記範囲であることで、比較的貴な電位領域における放電容量を良好な範囲に維持することができ、また、１．７７超の場合には、比較的卑な放電電位を示すことができる。 The lower limit of the half-value full width of the (002) plane diffraction peak by the manual method in X-ray diffraction using CuKα ray of the carbon material contained in the negative electrode active material for the non-aqueous electrolyte power storage element is preferably 0.5 ° or more. 0.0 ° is more preferable, 1.5 ° or more is further preferable, and more than 1.77 ° is even more preferable. The upper limit of the full width at half maximum of the (002) plane diffraction peak is preferably 5.0 ° or less. When the full width at half maximum of the (002) plane diffraction peak is in the above range, the discharge capacity in the relatively noble potential region can be maintained in a good range, and when it exceeds 1.77, a comparison is made. It can show a low-key discharge potential.
（エックス線回折測定）
　当該非水電解質蓄電素子用負極活物質が含有する炭素材料のエックス線回折（ＸＲＤ）測定は、エックス線回折装置（Ｒｉｇａｋｕ社製、型名：ＭｉｎｉＦｌｅｘ　ＩＩ）を用いて試料の粉末エックス線回折パターンを取得する。線源はＣｕＫα線、管電圧は３０ｋＶ、管電流は１５ｍＡとして行う。このとき、回折エックス線は、厚さ３０μｍのＫβフィルターを通り、高速一次元検出器（Ｄ／ｔｅＸ　Ｕｌｔｒａ　２）にて検出される。また、サンプリング幅は０．０２°、スキャンスピードは５°／ｍｉｎ、発散スリット幅は０．６２５°、受光スリット幅は１３ｍｍ（ＯＰＥＮ）、散乱スリット幅は８ｍｍとする。得られたパターンについて、統合粉末エックス線解析ソフトウェアＰＤＸＬを用いる場合、最適化によりピーク形状をフィッティングし、各回折ピークの位置及び半値全幅を得ることができる。ＰＤＸＬを用いず、マニュアル手法による場合、各回折ピークの位置及び半値全幅は、以下の手法により得ることができる。２θ＝１０°から２５°で最小強度を示す点と、２７°から３５°で最小強度を示す点を通る一次関数をバックグラウンドとして、処理前の強度から差し引く。そして、差し引いた後のパターンについて、２θ＝２０°から３０°の範囲における最大強度を示す点の２θ＝Ｘ°を回折ピークの位置とする。 ２θ＝２０°からＸ°の範囲において、最大強度の半値と最も近い強度を示す点と、 ２θ＝Ｘ°から３０°の範囲において、最大強度の半値に最も近い強度を示す点との２θの差を半値全幅とする。通常、２θ＝２４．５°から２６．５°に（００２）面、４０°から５０°に（１０）面、５０°から６０°に（００４）面に帰属可能な回折ピークが観測される。グラフェン層中の炭素に置換してドープされたホウ素によって、結晶性が変化し（１０）面回折ピークの位置が低角度側にシフトすると推測される。 (X-ray diffraction measurement)
For the X-ray diffraction (XRD) measurement of the carbon material contained in the negative electrode active material for the non-aqueous electrolyte power storage element, a powder X-ray diffraction pattern of the sample is obtained using an X-ray diffraction device (manufactured by Rigaku, model name: MiniFlex II). .. The radiation source is CuKα wire, the tube voltage is 30 kV, and the tube current is 15 mA. At this time, the diffracted X-rays pass through a Kβ filter having a thickness of 30 μm and are detected by a high-speed one-dimensional detector (D / teX Ultra 2). The sampling width is 0.02 °, the scan speed is 5 ° / min, the divergent slit width is 0.625 °, the light receiving slit width is 13 mm (OPEN), and the scattering slit width is 8 mm. When the integrated powder X-ray analysis software PDXL is used for the obtained pattern, the peak shape can be fitted by optimization, and the position and full width at half maximum of each diffraction peak can be obtained. In the case of a manual method without using PDXL, the position and full width at half maximum of each diffraction peak can be obtained by the following method. The linear function passing through the point showing the minimum intensity from 2θ = 10 ° to 25 ° and the point showing the minimum intensity from 27 ° to 35 ° is used as the background, and is subtracted from the intensity before processing. Then, for the pattern after subtraction, the position of the diffraction peak is 2θ = X °, which is the point showing the maximum intensity in the range of 2θ = 20 ° to 30 °. 2θ of 2θ between the point showing the strength closest to the half-value of the maximum intensity in the range of 2θ = 20 ° to X ° and the point showing the intensity closest to the half-value of the maximum intensity in the range of 2θ = X ° to 30 °. The difference is the full width at half maximum. Diffraction peaks that can be attributed to the (002) plane from 2θ = 24.5 ° to 26.5 °, the (10) plane from 40 ° to 50 °, and the (004) plane from 50 ° to 60 ° are usually observed. .. It is presumed that the boron substituted by substituting carbon in the graphene layer changes the crystallinity and shifts the position of the (10) plane diffraction peak to the low angle side.
　当該非水電解質蓄電素子用負極活物質が含有する炭素材料の、上記炭素材料を活物質として含む作用極と金属リチウムからなる対極とを備えるセルの放電過程で得られるｄＱ／ｄＶ曲線において、電圧範囲１．０Ｖ以上１．４Ｖ以下におけるｄＱ／ｄＶの最小値に対する、電圧範囲１．４Ｖ以上２．０Ｖ以下におけるｄＱ／ｄＶの最大値の比の下限としては、１．０３が好ましく、１．１８がより好ましい。上記ｄＱ／ｄＶ比が上記範囲であることで、当該負極活物質が非水電解質蓄電素子の負極に用いられた場合に、０．３５Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）程度以上の比較的貴な電位領域におけるクーロン効率を高めることができる。上記ｄＱ／ｄＶ比が高いほど、炭素材料のグラフェン層中の欠陥や官能基の形成は少なく、グラフェン層中の炭素にドープされたホウ素量が多いと考えられる。その結果、クーロン効率が高まると考えられる。 In the dQ / dV curve of the carbon material contained in the negative electrode active material for the non-aqueous electrolyte power storage element, the voltage is obtained in the discharge process of the cell having the working electrode containing the carbon material as the active material and the counter electrode made of metallic lithium. The lower limit of the ratio of the maximum value of dQ / dV in the voltage range of 1.4 V or more and 2.0 V or less to the minimum value of dQ / dV in the range of 1.0 V or more and 1.4 V or less is preferably 1.03. 18 is more preferable. When the negative electrode active material is used for the negative electrode of the non-aqueous electrolyte power storage element, the dQ / dV ratio is relatively noble at about 0.35 V (vs. Li / Li + ) or more. The Coulomb efficiency in the potential region can be increased. It is considered that the higher the dQ / dV ratio is, the less defects and functional groups are formed in the graphene layer of the carbon material, and the larger the amount of boron doped in the carbon in the graphene layer. As a result, the Coulomb efficiency is expected to increase.
（ｄＱ／ｄＶ比の算出）
　非水電解質蓄電素子から試料を準備する場合は、ｄＱ／ｄＶ比は、以下の手順で算出する。始めに、非水電解質蓄電素子を０．０５Ｃの電流で通常使用時の下限電圧まで定電流放電する。放電後の上記非水電解質蓄電素子を不活性雰囲気下にて解体し、負極を取り出し、ジメチルカーボネートで洗浄、乾燥して、改めて上記負極を作用極とし、金属リチウムからなる電極を対極としたセルを組み立てる。なお、対極が金属リチウムの場合、対極における金属リチウムの溶解・析出反応抵抗が極めて低いことから、充放電中の作用極と対極との間の電圧は、金属リチウムの酸化還元電位に対する作用極の電位とほぼ等しいとみなすことができる。
　得られたセルについて、２５℃にて、負極活物質１ｇあたり５０ｍＡの充電電流で、充電電圧を０．４Ｖとする定電流定電圧（ＣＣＣＶ）充電を行う。充電終止条件は、定電圧充電が開始してから１２時間経過した時点とする。１０分の休止後、２５℃にて、負極活物質１ｇあたり５０ｍＡの放電電流で、終止電圧を２．０Ｖとする定電流（ＣＣ）放電を行う。当該定電流放電時の挙動に基づいて、ｄＱ／ｄＶ曲線を得る。 (Calculation of dQ / dV ratio)
When preparing a sample from a non-aqueous electrolyte storage element, the dQ / dV ratio is calculated by the following procedure. First, the non-aqueous electrolyte power storage element is constantly discharged to the lower limit voltage during normal use with a current of 0.05 C. The non-aqueous electrolyte storage element after discharge is disassembled in an inert atmosphere, the negative electrode is taken out, washed with dimethyl carbonate and dried, and the negative electrode is used as the working electrode and the electrode made of metallic lithium is used as the counter electrode. To assemble. When the counter electrode is metallic lithium, the dissolution / precipitation reaction resistance of metallic lithium at the counter electrode is extremely low, so the voltage between the working electrode and the counter electrode during charging and discharging is the working electrode with respect to the redox potential of metallic lithium. It can be regarded as almost equal to the potential.
The obtained cell is charged with a constant current constant voltage (CCCV) having a charging voltage of 0.4 V at 25 ° C. with a charging current of 50 mA per 1 g of the negative electrode active material. The charge termination condition is 12 hours after the start of constant voltage charging. After a 10-minute rest, constant current (CC) discharge with a final voltage of 2.0 V is performed at 25 ° C. with a discharge current of 50 mA per 1 g of the negative electrode active material. A dQ / dV curve is obtained based on the behavior at the time of constant current discharge.
　ｄＱ／ｄＶ曲線を得る手順は次の通りとする。当該定電流放電において、セルの端子間電圧が０．０２Ｖ変化する毎に、端子間電圧Ｖの値（Ｖｎ）と当該定電流放電の開始からの積算通電電気量Ｑ（ｍＡｈ）の値（Ｑｎ）をデータとして蓄積する。ここでｎは自然数である。このデータに基づき、（Ｑｎ＋１－Ｑｎ）／（Ｖｎ＋１－Ｖｎ）の値を（Ｖｎ＋１＋Ｖｎ）／２の値に対してプロットし、ｄＱ／ｄＶ曲線を得る。
　得られたｄＱ／ｄＶ曲線より、電圧範囲１．０Ｖ以上１．４Ｖ以下におけるｄＱ／ｄＶの最小値に対する、電圧範囲１．４Ｖ以上２．０Ｖ以下におけるｄＱ／ｄＶの最大値の比をｄＱ／ｄＶ比とする。 The procedure for obtaining the dQ / dV curve is as follows. In the constant current discharge, every time the voltage between the terminals of the cell changes by 0.02 V, the value of the voltage V between the terminals (V n ) and the value of the integrated energization electricity Q (mAh) from the start of the constant current discharge (mAh). Q n ) is stored as data. Here, n is a natural number. Based on this data, the value of (Q n + 1 −Q n ) / (V n + 1 −V n ) is plotted against the value of (V n + 1 + V n ) / 2 to obtain a dQ / dV curve.
From the obtained dQ / dV curve, the ratio of the maximum value of dQ / dV in the voltage range of 1.4V or more and 2.0V or less to the minimum value of dQ / dV in the voltage range of 1.0V or more and 1.4V or less is dQ /. The dV ratio.
　当該負極活物質の８００℃超の雰囲気温度下における酸素の脱離量の上限値としては、上記炭素材料に対して２．４５質量％が好ましく、１．７９質量％がより好ましい。８００℃超の雰囲気温度下における酸素の脱離量が上記範囲であることで、充放電ヒステリシスを小さくできる。また、充放電ヒステリシスが小さくなることで、クーロン効率を向上できる。 The upper limit of the amount of oxygen desorbed from the negative electrode active material at an atmospheric temperature of more than 800 ° C. is preferably 2.45% by mass, more preferably 1.79% by mass with respect to the carbon material. When the amount of oxygen desorbed at an atmospheric temperature of more than 800 ° C. is within the above range, the charge / discharge hysteresis can be reduced. In addition, the Coulomb efficiency can be improved by reducing the charge / discharge hysteresis.
　上記酸素脱離量は、測定装置としてＨＯＲＩＢＡ社製酸素・窒素・水素分析装置「ＥＭＧＡ－９３０」を用いて以下の条件で測定する。
　酸素用検出器：不活性ガス融解－非分散型赤外線吸収法（ＮＤＩＲ）
　試料質量：２０ｍｇから２５ｍｇ
　ガス抽出炉電力：　インパルス炉出力：０から８．０ｋＷ（前もって出力と温度の関係を調べておき、設定温度ごとに変更する。）
　キャリアガス：Ｈｅ
　校正方法：標準試料を用いた１点校正
　積算条件：時間積算
　　　　　設定温度ごとに積算した時間
　　　　　（１）０秒から６０秒（４００℃）
　　　　　（２）６０秒から１１０秒（６００℃）
　　　　　（３）１１０秒から１６０秒（８００℃）
　　　　　（４）１６０秒から２１０秒（１０００℃）
　　　　　（５）２１０秒から２６０秒（１２００℃）
　　　　　（６）２６０秒から３３０秒（２５００℃）
　測定手順：黒鉛るつぼを抽出炉中に設置し、３２３１℃で３０秒間、次に４００℃で２０秒間空焼きすることで、るつぼに含まれる酸素を除去する。そのるつぼを大気下に取り出し、試料２０ｍｇから２５ｍｇを中に入れ、再度抽出炉中に設置する。次に、４００℃（５０秒）→６００℃（５０秒）→８００℃（５０秒）→１０００℃（５０秒）→１２００℃（５０秒）→２５００℃（５０秒）と段階的に昇温、加熱することで、試料から各温度で脱離する酸素を定量する。なお、空焼き後に大気に暴露したるつぼに再度酸素が吸着していることを考慮して、空焼き後に大気に暴露したるつぼ単体から脱離する酸素の量についても測定し、その分を除去する。すなわち、本発明における「８００℃超の雰囲気温度下における酸素の脱離量」とは、上記酸素分析における、１０００℃、１２００℃、２５００℃加熱時に脱離した酸素の合計、つまり、上記酸素分析における、１６０．１秒から３３０秒に検出された酸素の積算を意味する。 The oxygen desorption amount is measured under the following conditions using an oxygen / nitrogen / hydrogen analyzer "EMGA-930" manufactured by HORIBA as a measuring device.
Oxygen detector: Inert gas melting-non-dispersive infrared absorption method (NDIR)
Sample mass: 20 mg to 25 mg
Gas extraction furnace power: Impulse furnace output: 0 to 8.0 kW (Check the relationship between output and temperature in advance and change it for each set temperature.)
Carrier gas: He
Calibration method: 1-point calibration using a standard sample Integration condition: Time integration Time integrated for each set temperature (1) 0 seconds to 60 seconds (400 ° C)
(2) 60 seconds to 110 seconds (600 ° C)
(3) 110 seconds to 160 seconds (800 ° C)
(4) 160 seconds to 210 seconds (1000 ° C)
(5) 210 seconds to 260 seconds (1200 ° C)
(6) 260 seconds to 330 seconds (2500 ° C)
Measurement procedure: A graphite crucible is placed in an extraction furnace and baked at 3231 ° C. for 30 seconds and then at 400 ° C. for 20 seconds to remove oxygen contained in the crucible. The crucible is taken out to the atmosphere, 20 mg to 25 mg of the sample is put in the crucible, and the crucible is placed in the extraction furnace again. Next, the temperature is gradually raised in the order of 400 ° C. (50 seconds) → 600 ° C. (50 seconds) → 800 ° C. (50 seconds) → 1000 ° C. (50 seconds) → 1200 ° C. (50 seconds) → 2500 ° C. (50 seconds). By heating, the amount of oxygen desorbed from the sample at each temperature is quantified. Considering that oxygen is adsorbed again in the crucible exposed to the atmosphere after air-baking, the amount of oxygen desorbed from the crucible alone exposed to the air after air-baking is also measured and the amount is removed. .. That is, the "amount of oxygen desorbed at an atmospheric temperature exceeding 800 ° C." in the present invention is the total amount of oxygen desorbed when heated at 1000 ° C., 1200 ° C. and 2500 ° C. in the oxygen analysis, that is, the oxygen analysis. Means the integration of oxygen detected from 160.1 seconds to 330 seconds in.
　当該負極活物質は、上記炭素材料のみから形成されていてもよく、本発明の効果が奏される限り、上記炭素材料以外の他の負極活物質が含まれていてもよい。また、当該負極活物質は、上記炭素材料以外の他の炭素材料を含有していてもよい。他の負極活物質としては、例えば上記炭素材料以外の難黒鉛化性炭素、易黒鉛化性炭素、黒鉛等の他の炭素材料、Ｓｉ等の半金属、Ｓｎ等の金属、これら半金属又は金属の酸化物、又は、これら半金属又は金属と炭素材料との複合体等が挙げられる。 The negative electrode active material may be formed only from the above carbon material, and may contain other negative electrode active materials other than the above carbon material as long as the effect of the present invention is exhibited. Further, the negative electrode active material may contain a carbon material other than the above carbon material. Examples of other negative electrode active materials include non-graphitizable carbon other than the above carbon materials, easily graphitizable carbon, other carbon materials such as graphite, semi-metals such as Si, metals such as Sn, these semi-metals or metals. Or the oxide of the above, or a composite of these semi-metals or metals and a carbon material, and the like.
　当該負極活物質における上記炭素材料の含有量としては、７０質量％以上が好ましく、８０質量％以上がより好ましく、９０質量％以上がさらに好ましい。上記炭素材料の含有量を高めることで、０．３５Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）程度以上の比較的貴な電位領域における質量あたりの放電容量及びクーロン効率をより高めることができる。 The content of the carbon material in the negative electrode active material is preferably 70% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more. By increasing the content of the carbon material, the discharge capacity per mass and the Coulomb efficiency in a relatively noble potential region of about 0.35 V (vs. Li / Li + ) or more can be further increased.
　当該負極活物質の製造方法は特に限定されない。上記ホウ素を含み、層状の結晶構造を有する炭素材料の製造方法としては、例えば上記ＣＶＤ法によって合成することができる。具体的には、上記炭素材料の製造方法は、ホウ素源ガス及び炭素源ガスを含む原料ガスを石英管等の反応容器内に導入し、電気炉等による高温下でＣＶＤ法により合成させることを有していてもよい。上記合成工程における反応温度としては、７００℃以上１１００℃以下が好ましい。 The method for producing the negative electrode active material is not particularly limited. As a method for producing a carbon material containing boron and having a layered crystal structure, for example, it can be synthesized by the CVD method. Specifically, the method for producing a carbon material is to introduce a boron source gas and a raw material gas containing a carbon source gas into a reaction vessel such as a quartz tube and synthesize them by a CVD method at a high temperature in an electric furnace or the like. You may have. The reaction temperature in the synthesis step is preferably 700 ° C. or higher and 1100 ° C. or lower.
　上記ＣＶＤ法により合成するためのホウ素源ガスとしては、例えばＢＣｌ３などのハロゲン化ホウ素が挙げられる。また、炭素源ガスとしては、例えばベンゼン、アセチレン、エチレン、メタン、エタン、プロパンなどの炭化水素が挙げられる。また、上記原料ガスに加えて窒素等のキャリアガスを用いることが好ましい。 Examples of the boron source gas for synthesis by the above CVD method include boron halide such as BCl 3 . Examples of the carbon source gas include hydrocarbons such as benzene, acetylene, ethylene, methane, ethane, and propane. Further, it is preferable to use a carrier gas such as nitrogen in addition to the above raw material gas.
　上記合成工程により反応容器内に析出した炭素材料は、再熱処理を行うことが好ましい。再熱処理工程では、析出した炭素材料を回収して真空置換炉にて再熱処理を行う。上記再熱処理工程は、例えば窒素雰囲気下にて行われる。上記再熱処理温度としては、６００℃以上１０００℃以下が好ましい。再熱処理後の炭素材料は、粉砕後に負極活物質として用いられる。上記炭素材料の粉砕の方法は上記粉砕方法から適宜選択できる。 It is preferable to reheat the carbon material deposited in the reaction vessel by the above synthesis step. In the reheat treatment step, the precipitated carbon material is recovered and reheated in a vacuum replacement furnace. The reheat treatment step is performed, for example, in a nitrogen atmosphere. The reheat treatment temperature is preferably 600 ° C. or higher and 1000 ° C. or lower. The carbon material after reheat treatment is used as a negative electrode active material after pulverization. The method for crushing the carbon material can be appropriately selected from the above crushing methods.
＜非水電解質蓄電素子用負極＞
　本発明の一実施形態に係る非水電解質蓄電素子用負極は、当該負極活物質を含有する。当該負極は、当該負極活物質を含有するため、０．３５Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）程度以上の比較的貴な電位領域における質量あたりの放電容量及びクーロン効率を高めることができる。 <Negative electrode for non-aqueous electrolyte power storage element>
The negative electrode for a non-aqueous electrolyte power storage element according to an embodiment of the present invention contains the negative electrode active material. Since the negative electrode contains the negative electrode active material, it is possible to increase the discharge capacity per mass and the Coulomb efficiency in a relatively noble potential region of about 0.35 V (vs. Li / Li + ) or more.
　負極は、負極基材と、当該負極基材に直接又は中間層を介して配される負極活物質層とを有する。 The negative electrode has a negative electrode base material and a negative electrode active material layer arranged directly on the negative electrode base material or via an intermediate layer.
（負極基材）
　負極基材は、導電性を有する。「導電性」を有するか否かは、ＪＩＳ－Ｈ－０５０５（１９７５年）に準拠して測定される体積抵抗率が１０７Ω・ｃｍを閾値として判定する。負極基材の材料としては、銅、ニッケル、ステンレス鋼、ニッケルメッキ鋼、アルミニウム等の金属又はそれらの合金、炭素質材料等が挙げられ、負極の作動電位が０．３５Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）以上となる場合には、純アルミニウム又はアルミニウム合金からなることが好ましい。当該非水電解質蓄電素子用負極は純アルミニウム又はアルミニウム合金からなる負極基材をさらに有することで、低コスト化、軽量化を図ることができる。 (Negative electrode base material)
The negative electrode substrate has conductivity. Whether or not it has "conductivity" is determined with a volume resistivity of 107 Ω · cm measured in accordance with JIS-H-0505 (1975) as a threshold value. Examples of the material of the negative electrode base material include metals such as copper, nickel, stainless steel, nickel-plated steel, and aluminum or alloys thereof, carbonaceous materials, and the like, and the operating potential of the negative electrode is 0.35 V (vs. Li / Li). + ) Or more, it is preferably made of pure aluminum or an aluminum alloy. By further having a negative electrode base material made of pure aluminum or an aluminum alloy, the negative electrode for the non-aqueous electrolyte power storage element can be reduced in cost and weight.
　「純アルミニウム」とは、アルミニウムの純度が９９．００質量％以上のものをいい、例えばＪＩＳ－Ｈ４０００（２０１４）に規定の１０００番台のアルミニウムが挙げられる。また、「アルミニウム合金」とは、最も多く含まれる含有成分がアルミニウムである金属であってアルミニウムの純度が９９．００質量％未満のものをいい、例えば上記ＪＩＳに規定の１０００番台以外のアルミニウムが挙げられる。上記ＪＩＳに規定の１０００番台以外のアルミニウムとは、例えば上記ＪＩＳに規定の２０００番台のアルミニウム、３０００番台のアルミニウム、４０００番台のアルミニウム、５０００番台のアルミニウム、６０００番台のアルミニウム、７０００番台のアルミニウム等が挙げられる。 "Pure aluminum" refers to aluminum having a purity of 99.00% by mass or more, and examples thereof include aluminum in the 1000s specified in JIS-H4000 (2014). Further, the "aluminum alloy" refers to a metal in which the most contained component is aluminum and the purity of aluminum is less than 99.00% by mass. For example, aluminum other than the 1000 series specified in the above JIS is used. Can be mentioned. Aluminum other than the 1000 series specified in the JIS includes, for example, 2000 series aluminum, 3000 series aluminum, 4000 series aluminum, 5000 series aluminum, 6000 series aluminum, 7000 series aluminum, etc. specified in the above JIS. Can be mentioned.
　負極基材のアルミニウム純度としては８５％以上が好ましく、９０％以上がより好ましく、９５％以上がさらに好ましい。負極基材としては、例えばＪＩＳ－Ｈ４０００（２０１４）に規定される１０００番台の純アルミニウム、３０００番のアルミニウム－マンガン系合金、５０００番台のアルミニウム－マグネシウム系合金等を用いることができる。 The aluminum purity of the negative electrode base material is preferably 85% or more, more preferably 90% or more, still more preferably 95% or more. As the negative electrode base material, for example, pure aluminum in the 1000s specified in JIS-H4000 (2014), aluminum-manganese-based alloys in the 3000s, aluminum-magnesium alloys in the 5000s, and the like can be used.
　負極基材としては、箔、蒸着膜等が挙げられ、コストの観点から箔が好ましい。したがって、負極基材としてはアルミニウム箔又はアルミニウム合金箔が好ましい。 Examples of the negative electrode base material include foils and thin-film deposition films, and foils are preferable from the viewpoint of cost. Therefore, aluminum foil or aluminum alloy foil is preferable as the negative electrode base material.
　負極基材の平均厚さは、２μｍ以上３５μｍ以下が好ましく、３μｍ以上３０μｍ以下がより好ましく、４μｍ以上２５μｍ以下がさらに好ましく、５μｍ以上２０μｍ以下が特に好ましい。負極基材の平均厚さを上記の範囲とすることで、負極基材の強度を高めつつ、非水電解質蓄電素子の体積当たりのエネルギー密度を高めることができる。 The average thickness of the negative electrode substrate is preferably 2 μm or more and 35 μm or less, more preferably 3 μm or more and 30 μm or less, further preferably 4 μm or more and 25 μm or less, and particularly preferably 5 μm or more and 20 μm or less. By setting the average thickness of the negative electrode base material within the above range, it is possible to increase the energy density per volume of the non-aqueous electrolyte power storage element while increasing the strength of the negative electrode base material.
　中間層は、負極基材と負極活物質層との間に配される層である。中間層は、炭素粒子等の導電剤を含むことで負極基材と負極活物質層との接触抵抗を低減する。中間層の構成は特に限定されず、例えば、バインダ及び導電剤を含む。 The intermediate layer is a layer arranged between the negative electrode base material and the negative electrode active material layer. The intermediate layer contains a conductive agent such as carbon particles to reduce the contact resistance between the negative electrode base material and the negative electrode active material layer. The composition of the intermediate layer is not particularly limited and includes, for example, a binder and a conductive agent.
（負極活物質層）
　負極活物質層は当該負極活物質を含む。負極活物質層は、必要に応じて導電剤、バインダ、増粘剤、フィラー等の任意成分を含む。当該負極活物質の構成は上述の通りである。 (Negative electrode active material layer)
The negative electrode active material layer contains the negative electrode active material. The negative electrode active material layer contains optional components such as a conductive agent, a binder, a thickener, and a filler, if necessary. The composition of the negative electrode active material is as described above.
　負極活物質層における負極活物質の含有量は、６０質量％以上９９質量％以下が好ましく、９０質量％以上９８質量％以下がより好ましい。負極活物質の含有量を上記の範囲とすることで、負極活物質層の高エネルギー密度化と製造性を両立できる。 The content of the negative electrode active material in the negative electrode active material layer is preferably 60% by mass or more and 99% by mass or less, and more preferably 90% by mass or more and 98% by mass or less. By setting the content of the negative electrode active material within the above range, it is possible to achieve both high energy density and manufacturability of the negative electrode active material layer.
　当該負極活物質が含有する上記炭素材料も導電性を有するが、負極活物質層は上記導電剤としてカーボンナノチューブを含有することが好ましい。当該負極活物質層がカーボンナノチューブを含有することで、過充電時におけるクーロン効率を向上できる。カーボンナノチューブは、円筒形状の繊維状炭素材料である。カーボンナノチューブは、単層でも多層でもよい。また、カーボンナノチューブは、１種を単独で用いてもよく、２種以上のものを併用してもよい。 The carbon material contained in the negative electrode active material also has conductivity, but the negative electrode active material layer preferably contains carbon nanotubes as the conductive agent. Since the negative electrode active material layer contains carbon nanotubes, the coulombic efficiency at the time of overcharging can be improved. Carbon nanotubes are cylindrical fibrous carbon materials. The carbon nanotubes may be single-walled or multi-walled. In addition, one type of carbon nanotube may be used alone, or two or more types may be used in combination.
　負極活物質層におけるカーボンナノチューブの含有量の下限としては、０．０１質量％が好ましく、０．０２質量％がより好ましい。上記カーボンナノチューブの含有量の上限としては、２質量％が好ましく、１質量％がより好ましい。上記カーボンナノチューブの含有量を上記下限以上又は上限以下とすることで、負極活物質層形成用の負極合剤ペーストの過剰な粘度上昇を抑制しつつ、過充電時におけるクーロン効率を向上できる。 The lower limit of the carbon nanotube content in the negative electrode active material layer is preferably 0.01% by mass, more preferably 0.02% by mass. The upper limit of the content of the carbon nanotubes is preferably 2% by mass, more preferably 1% by mass. By setting the content of the carbon nanotubes to the lower limit or higher or lower than the upper limit, it is possible to improve the Coulomb efficiency at the time of overcharging while suppressing an excessive increase in viscosity of the negative electrode mixture paste for forming the negative electrode active material layer.
　上記カーボンナノチューブの平均長さの下限としては、３μｍが好ましく、５μｍがより好ましい。上記カーボンナノチューブの平均長さの上限としては、３００μｍが好ましく、２００μｍがより好ましい。上記カーボンナノチューブの平均長さを上記下限以上又は上限以下とすることで、負極活物質層中の電子伝導経路のネットワークが形成されやすくなり、過充電時におけるクーロン効率を向上できる。 The lower limit of the average length of the carbon nanotubes is preferably 3 μm, more preferably 5 μm. The upper limit of the average length of the carbon nanotubes is preferably 300 μm, more preferably 200 μm. By setting the average length of the carbon nanotubes to be equal to or higher than the lower limit or lower than the upper limit, a network of electron conduction paths in the negative electrode active material layer can be easily formed, and the Coulomb efficiency at the time of overcharging can be improved.
　当該負極活物質層は、カーボンナノチューブ以外のその他の導電剤を含有していてもよい。その他の導電剤としては、導電性材料であれば特に限定されない。このような導電剤としては、例えば、炭素質材料、金属、導電性セラミックス等が挙げられる。炭素質材料としては、黒鉛化炭素、非黒鉛化炭素、グラフェン系炭素等が挙げられる。非黒鉛化炭素としては、カーボンナノファイバー、ピッチ系炭素繊維、カーボンブラック等が挙げられる。カーボンブラックとしては、ファーネスブラック、アセチレンブラック、ケッチェンブラック等が挙げられる。グラフェン系炭素としては、グラフェン、フラーレン等が挙げられる。その他の導電剤の形状としては、粉状、繊維状等が挙げられる。その他の導電剤としては、これらの材料の１種を単独で用いてもよく、２種以上を混合して用いてもよい。また、これらの材料を複合化して用いてもよい。その他の導電剤としては、これらの中でも電子伝導性及び塗工性の観点よりカーボンブラックが好ましく、中でもアセチレンブラックが好ましい。 The negative electrode active material layer may contain other conductive agents other than carbon nanotubes. The other conductive agent is not particularly limited as long as it is a conductive material. Examples of such a conductive agent include carbonaceous materials, metals, conductive ceramics and the like. Examples of the carbonaceous material include graphitized carbon, non-graphitized carbon, graphene-based carbon and the like. Examples of the non-graphitized carbon include carbon nanofibers, pitch-based carbon fibers, and carbon black. Examples of carbon black include furnace black, acetylene black, and ketjen black. Examples of graphene-based carbons include graphene and fullerenes. Examples of the shape of the other conductive agent include powder and fibrous. As the other conductive agent, one of these materials may be used alone, or two or more of them may be mixed and used. Further, these materials may be used in combination. Among these, carbon black is preferable as the other conductive agent from the viewpoint of electron conductivity and coatability, and acetylene black is particularly preferable.
　負極活物質層における導電剤の総含有量は、１質量％以上１０質量％以下が好ましく、３質量％以上９質量％以下がより好ましい。導電剤の総含有量を上記の範囲とすることで、非水電解質蓄電素子のエネルギー密度を高めることができる。 The total content of the conductive agent in the negative electrode active material layer is preferably 1% by mass or more and 10% by mass or less, and more preferably 3% by mass or more and 9% by mass or less. By setting the total content of the conductive agent in the above range, the energy density of the non-aqueous electrolyte power storage element can be increased.
　バインダとしては、例えば、フッ素樹脂（ポリテトラフルオロエチレン（ＰＴＦＥ）、ポリフッ化ビニリデン（ＰＶＤＦ）等）、ポリエチレン、ポリプロピレン、ポリアクリル、ポリイミド等の熱可塑性樹脂；エチレン－プロピレン－ジエンゴム（ＥＰＤＭ）、スルホン化ＥＰＤＭ、スチレンブタジエンゴム（ＳＢＲ）、フッ素ゴム等のエラストマー；多糖類高分子等が挙げられる。 Examples of the binder include fluororesins (polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), etc.), thermoplastic resins such as polyethylene, polypropylene, polyacrylics, and polyimides; ethylene-propylene-diene rubber (EPDM), sulfone. Elastomers such as polyethylene chemicals, styrene butadiene rubber (SBR), fluororubber; and polysaccharide polymers can be mentioned.
　負極活物質層におけるバインダの含有量は、１質量％以上１０質量％以下が好ましく、３質量％以上９質量％以下がより好ましい。バインダの含有量を上記の範囲とすることで、負極活物質を安定して保持することができる。 The binder content in the negative electrode active material layer is preferably 1% by mass or more and 10% by mass or less, and more preferably 3% by mass or more and 9% by mass or less. By setting the binder content within the above range, the negative electrode active material can be stably held.
　増粘剤としては、例えば、カルボキシメチルセルロース（ＣＭＣ）、メチルセルロース等の多糖類高分子が挙げられる。増粘剤がリチウム等と反応する官能基を有する場合、予めメチル化等によりこの官能基を失活させてもよい。 Examples of the thickener include polysaccharide polymers such as carboxymethyl cellulose (CMC) and methyl cellulose. When the thickener has a functional group that reacts with lithium or the like, this functional group may be deactivated by methylation or the like in advance.
　フィラーは、特に限定されない。フィラーとしては、ポリプロピレン、ポリエチレン等のポリオレフィン、二酸化ケイ素、アルミナ、二酸化チタン、酸化カルシウム、酸化ストロンチウム、酸化バリウム、酸化マグネシウム、アルミノケイ酸塩等の無機酸化物、水酸化マグネシウム、水酸化カルシウム、水酸化アルミニウム等の水酸化物、炭酸カルシウム等の炭酸塩、フッ化カルシウム、フッ化バリウム、硫酸バリウム等の難溶性のイオン結晶、窒化アルミニウム、窒化ケイ素等の窒化物、タルク、モンモリロナイト、ベーマイト、ゼオライト、アパタイト、カオリン、ムライト、スピネル、オリビン、セリサイト、ベントナイト、マイカ等の鉱物資源由来物質又はこれらの人造物等が挙げられる。 The filler is not particularly limited. Fillers include polyolefins such as polypropylene and polyethylene, silicon dioxide, alumina, titanium dioxide, calcium oxide, strontium oxide, barium oxide, magnesium oxide, inorganic oxides such as aluminosilicate, magnesium hydroxide, calcium hydroxide, and hydroxide. Hydroxides such as aluminum, carbonates such as calcium carbonate, sparingly soluble ion crystals such as calcium fluoride, barium fluoride, barium sulfate, nitrides such as aluminum nitride and silicon nitride, talc, montmorillonite, boehmite, zeolite, etc. Examples thereof include mineral resource-derived substances such as apatite, kaolin, mulite, spinel, olivine, sericite, bentonite, and mica, or man-made products thereof.
　負極活物質層は、Ｂ、Ｎ、Ｐ、Ｆ、Ｃｌ、Ｂｒ、Ｉ等の典型非金属元素、Ｌｉ、Ｎａ、Ｍｇ、Ａｌ、Ｋ、Ｃａ、Ｚｎ、Ｇａ、Ｇｅ、Ｓｎ、Ｓｒ、Ｂａ、等の典型金属元素、Ｓｃ、Ｔｉ、Ｖ、Ｃｒ、Ｍｎ、Ｆｅ、Ｃｏ、Ｎｉ、Ｃｕ、Ｍｏ、Ｚｒ、Ｔａ、Ｈｆ、Ｎｂ、Ｗ等の遷移金属元素を負極活物質、導電剤、バインダ、増粘剤、フィラー以外の成分として含有してもよい。 The negative electrode active material layer is a typical non-metal element such as B, N, P, F, Cl, Br, I, Li, Na, Mg, Al, K, Ca, Zn, Ga, Ge, Sn, Sr, Ba, etc. Typical metal elements such as Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Mo, Zr, Ta, Hf, Nb, W and other transition metal elements are used as negative electrode active materials, conductive agents, binders, etc. It may be contained as a component other than a thickener and a filler.
＜非水電解質蓄電素子＞
　本発明の一実施形態に係る非水電解質蓄電素子（以下、単に「蓄電素子」ともいう。）は、正極、負極及びセパレータを有する電極体と、非水電解質と、上記電極体及び非水電解質を収容する容器と、を備える。電極体は、通常、複数の正極及び複数の負極がセパレータを介して積層された積層型、又は、正極及び負極がセパレータを介して積層された状態で巻回された巻回型である。非水電解質は、正極、負極及びセパレータに含浸された状態で存在する。非水電解質蓄電素子の一例として、非水電解質二次電池（以下、単に「二次電池」ともいう。）について説明する。 <Non-water electrolyte power storage element>
The non-aqueous electrolyte power storage element (hereinafter, also simply referred to as “storage element”) according to the embodiment of the present invention includes an electrode body having a positive electrode, a negative electrode and a separator, a non-aqueous electrolyte, and the above-mentioned electrode body and non-water electrolyte. It is equipped with a container for accommodating. The electrode body is usually a laminated type in which a plurality of positive electrodes and a plurality of negative electrodes are laminated via a separator, or a wound type in which a positive electrode and a negative electrode are laminated via a separator. The non-aqueous electrolyte exists in a state of being impregnated in the positive electrode, the negative electrode and the separator. As an example of the non-aqueous electrolyte power storage element, a non-aqueous electrolyte secondary battery (hereinafter, also simply referred to as “secondary battery”) will be described.
　本発明の一実施形態に係る非水電解質蓄電素子は、上記非水電解質蓄電素子用負極を備える。当該非水電解質蓄電素子は、上記負極活物質を含有する負極を備えるため、０．３５Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）程度以上の比較的貴な電位領域における質量あたりの放電容量及びクーロン効率を高めることができる。 The non-aqueous electrolyte power storage element according to the embodiment of the present invention includes the negative electrode for the non-water electrolyte power storage element. Since the non-aqueous electrolyte power storage element includes a negative electrode containing the negative electrode active material, the discharge capacity per mass and the Coulomb efficiency in a relatively noble potential region of about 0.35 V (vs. Li / Li + ) or more can be obtained. Can be enhanced.
（正極）
　正極は、正極基材と、当該正極基材に直接又は中間層を介して配される正極活物質層とを有する。中間層の構成は特に限定されず、例えば上記負極で例示した構成から選択することができる。 (Positive electrode)
The positive electrode has a positive electrode base material and a positive electrode active material layer arranged directly on the positive electrode base material or via an intermediate layer. The configuration of the intermediate layer is not particularly limited, and can be selected from, for example, the configurations exemplified by the negative electrode.
　正極基材は、導電性を有する。正極基材の材質としては、アルミニウム、チタン、タンタル、ステンレス鋼等の金属又はこれらの合金が用いられる。これらの中でも、耐電位性、導電性の高さ、及びコストの観点からアルミニウム又はアルミニウム合金が好ましい。正極基材としては、箔、蒸着膜、メッシュ、多孔質材料等が挙げられ、コストの観点から箔が好ましい。したがって、正極基材としてはアルミニウム箔又はアルミニウム合金箔が好ましい。アルミニウム又はアルミニウム合金としては、ＪＩＳ－Ｈ－４０００（２０１４年）又はＪＩＳ－Ｈ４１６０（２００６年）に規定されるＡ１０８５、Ａ３００３、Ａ１Ｎ３０等が例示できる。 The positive electrode base material has conductivity. As the material of the positive electrode base material, a metal such as aluminum, titanium, tantalum, or stainless steel or an alloy thereof is used. Among these, aluminum or an aluminum alloy is preferable from the viewpoint of potential resistance, high conductivity, and cost. Examples of the positive electrode base material include foils, thin-film deposition films, meshes, porous materials, and the like, and foils are preferable from the viewpoint of cost. Therefore, aluminum foil or aluminum alloy foil is preferable as the positive electrode base material. Examples of aluminum or aluminum alloy include A1085, A3003, and A1N30 specified in JIS-H-4000 (2014) or JIS-H4160 (2006).
　正極基材の平均厚さは、３μｍ以上５０μｍ以下が好ましく、５μｍ以上４０μｍ以下がより好ましく、８μｍ以上３０μｍ以下がさらに好ましく、１０μｍ以上２５μｍ以下が特に好ましい。正極基材の平均厚さを上記の範囲とすることで、正極基材の強度を高めつつ、二次電池の体積当たりのエネルギー密度を高めることができる。 The average thickness of the positive electrode substrate is preferably 3 μm or more and 50 μm or less, more preferably 5 μm or more and 40 μm or less, further preferably 8 μm or more and 30 μm or less, and particularly preferably 10 μm or more and 25 μm or less. By setting the average thickness of the positive electrode base material in the above range, it is possible to increase the energy density per volume of the secondary battery while increasing the strength of the positive electrode base material.
　正極活物質層は、正極活物質を含む。正極活物質層は、必要に応じて、導電剤、バインダ、増粘剤、フィラー等の任意成分を含む。 The positive electrode active material layer contains the positive electrode active material. The positive electrode active material layer contains optional components such as a conductive agent, a binder, a thickener, and a filler, if necessary.
　正極活物質としては、公知の正極活物質の中から適宜選択できる。リチウムイオン二次電池用の正極活物質としては、通常、リチウムイオンを吸蔵及び放出することができる材料が用いられる。正極活物質としては、例えば、α－ＮａＦｅＯ２型結晶構造を有するリチウム遷移金属複合酸化物、スピネル型結晶構造を有するリチウム遷移金属複合酸化物、ポリアニオン化合物、カルコゲン化合物、硫黄等が挙げられる。α－ＮａＦｅＯ２型結晶構造を有するリチウム遷移金属複合酸化物として、例えば、Ｌｉ［ＬｉｘＮｉ（１－ｘ）］Ｏ２（０≦ｘ＜０．５）、Ｌｉ［ＬｉｘＮｉγＣｏ（１－ｘ－γ）］Ｏ２（０≦ｘ＜０．５、０＜γ＜１）、Ｌｉ［ＬｉｘＣｏ（１－ｘ）］Ｏ２（０≦ｘ＜０．５）、Ｌｉ［ＬｉｘＮｉγＭｎ（１－ｘ－γ）］Ｏ２（０≦ｘ＜０．５、０＜γ＜１）、Ｌｉ［ＬｉｘＮｉγＭｎβＣｏ（１－ｘ－γ－β）］Ｏ２（０≦ｘ＜０．５、０＜γ、０＜β、０．５＜γ＋β＜１）、Ｌｉ［ＬｉｘＮｉγＣｏβＡｌ（１－ｘ－γ－β）］Ｏ２（０≦ｘ＜０．５、０＜γ、０＜β、０．５＜γ＋β＜１）等が挙げられる。スピネル型結晶構造を有するリチウム遷移金属複合酸化物として、ＬｉｘＭｎ２Ｏ４、ＬｉｘＮｉγＭｎ（２－γ）Ｏ４等が挙げられる。ポリアニオン化合物として、ＬｉＦｅＰＯ４、ＬｉＭｎＰＯ４、ＬｉＮｉＰＯ４、ＬｉＣｏＰＯ４，Ｌｉ３Ｖ２（ＰＯ４）３、Ｌｉ２ＭｎＳｉＯ４、Ｌｉ２ＣｏＰＯ４Ｆ等が挙げられる。カルコゲン化合物として、二硫化チタン、二硫化モリブデン、二酸化モリブデン等が挙げられる。これらの材料中の原子又はポリアニオンは、他の元素からなる原子又はアニオン種で一部が置換されていてもよい。これらの材料は表面が他の材料で被覆されていてもよい。正極活物質層においては、これら材料の１種を単独で用いてもよく、２種以上を混合して用いてもよい。 The positive electrode active material can be appropriately selected from known positive electrode active materials. As the positive electrode active material for a lithium ion secondary battery, a material capable of storing and releasing lithium ions is usually used. Examples of the positive electrode active material include a lithium transition metal composite oxide having an α-NaFeO type 2 crystal structure, a lithium transition metal composite oxide having a spinel type crystal structure, a polyanionic compound, a chalcogen compound, sulfur and the like. Examples of the lithium transition metal composite oxide having an α-NaFeO type 2 crystal structure include Li [Li x Ni (1-x) ] O 2 (0 ≦ x <0.5) and Li [Li x Ni γ Co ( 0 ≦ x <0.5). 1-x-γ) ] O 2 (0 ≦ x <0.5, 0 <γ <1), Li [Li x Co (1-x) ] O 2 (0 ≦ x <0.5), Li [ Li x Ni γ Mn (1-x-γ) ] O 2 (0 ≦ x <0.5, 0 <γ <1), Li [Li x Ni γ Mn β Co (1-x-γ-β) ] O 2 (0≤x <0.5, 0 <γ, 0 <β, 0.5 <γ + β <1), Li [Li x Ni γ Co β Al (1-x-γ-β) ] O 2 ( Examples thereof include 0 ≦ x <0.5, 0 <γ, 0 <β, 0.5 <γ + β <1). Examples of the lithium transition metal composite oxide having a spinel-type crystal structure include Li x Mn 2 O 4 and Li x Ni γ Mn (2-γ) O 4 . Examples of the polyanionic compound include LiFePO 4 , LiMnPO 4 , LiNiPO 4 , LiCoPO 4 , Li 3 V 2 (PO 4 ) 3 , Li 2 MnSiO 4 , Li 2 CoPO 4 F and the like. Examples of the chalcogen compound include titanium disulfide, molybdenum disulfide, molybdenum dioxide and the like. The atoms or polyanions in these materials may be partially substituted with atoms or anion species consisting of other elements. The surface of these materials may be coated with other materials. In the positive electrode active material layer, one of these materials may be used alone, or two or more of them may be mixed and used.
　正極活物質は、通常、粒子（粉体）である。正極活物質の平均粒径は、例えば、０．１μｍ以上２０μｍ以下とすることが好ましい。正極活物質の平均粒径を上記下限以上とすることで、正極活物質の製造又は取り扱いが容易になる。正極活物質の平均粒径を上記上限以下とすることで、正極活物質層の電子伝導性が向上する。なお、正極活物質と他の材料との複合体を用いる場合、該複合体の平均粒径を正極活物質の平均粒径とする。粉体を所定の粒径で得るためには粉砕機や分級機等が用いられる。粉砕方法及び粉級方法は、例えば、上記負極で例示した方法から選択できる。 The positive electrode active material is usually particles (powder). The average particle size of the positive electrode active material is preferably 0.1 μm or more and 20 μm or less, for example. By setting the average particle size of the positive electrode active material to the above lower limit or more, the production or handling of the positive electrode active material becomes easy. By setting the average particle size of the positive electrode active material to the above upper limit or less, the electron conductivity of the positive electrode active material layer is improved. When a composite of a positive electrode active material and another material is used, the average particle size of the composite is taken as the average particle size of the positive electrode active material. A crusher, a classifier, or the like is used to obtain a powder having a predetermined particle size. The pulverization method and the powder grade method can be selected from, for example, the methods exemplified for the negative electrode.
　正極活物質層における正極活物質の含有量は、５０質量％以上９９質量％以下が好ましく、７０質量％以上９８質量％以下がより好ましく、８０質量％以上９５質量％以下がさらに好ましい。正極活物質の含有量を上記の範囲とすることで、正極活物質層の高エネルギー密度化と製造性を両立できる。 The content of the positive electrode active material in the positive electrode active material layer is preferably 50% by mass or more and 99% by mass or less, more preferably 70% by mass or more and 98% by mass or less, and further preferably 80% by mass or more and 95% by mass or less. By setting the content of the positive electrode active material within the above range, it is possible to achieve both high energy density and manufacturability of the positive electrode active material layer.
　上記導電剤としては、導電性材料であれば特に限定されない。このような導電剤としては、上記負極で例示した材料から選択できる。 The conductive agent is not particularly limited as long as it is a conductive material. The conductive agent can be selected from the materials exemplified for the negative electrode.
　正極活物質層における導電剤の含有量は、１質量％以上１０質量％以下が好ましく、３質量％以上９質量％以下がより好ましい。導電剤の含有量を上記の範囲とすることで、二次電池のエネルギー密度を高めることができる。 The content of the conductive agent in the positive electrode active material layer is preferably 1% by mass or more and 10% by mass or less, and more preferably 3% by mass or more and 9% by mass or less. By setting the content of the conductive agent in the above range, the energy density of the secondary battery can be increased.
　上記バインダとしては、上記負極で例示した材料から選択できる。 The binder can be selected from the materials exemplified for the negative electrode.
　正極活物質層におけるバインダの含有量は、１質量％以上１０質量％以下が好ましく、３質量％以上９質量％以下がより好ましい。バインダの含有量を上記の範囲とすることで、活物質を安定して保持することができる。 The binder content in the positive electrode active material layer is preferably 1% by mass or more and 10% by mass or less, and more preferably 3% by mass or more and 9% by mass or less. By setting the binder content within the above range, the active substance can be stably retained.
　上記増粘剤としては、上記負極で例示した材料から選択できる。 The thickener can be selected from the materials exemplified in the negative electrode.
　上記フィラーとしては、上記負極で例示した材料から選択できる。 The filler can be selected from the materials exemplified for the negative electrode.
　正極活物質層は、Ｂ、Ｎ、Ｐ、Ｆ、Ｃｌ、Ｂｒ、Ｉ等の典型非金属元素、Ｌｉ、Ｎａ、Ｍｇ、Ａｌ、Ｋ、Ｃａ、Ｚｎ、Ｇａ、Ｇｅ、Ｓｎ、Ｓｒ、Ｂａ等の典型金属元素、Ｓｃ、Ｔｉ、Ｖ、Ｃｒ、Ｍｎ、Ｆｅ、Ｃｏ、Ｎｉ、Ｃｕ、Ｍｏ、Ｚｒ、Ｎｂ、Ｗ等の遷移金属元素を正極活物質、導電剤、バインダ、増粘剤、フィラー以外の成分として含有してもよい。 The positive electrode active material layer includes typical non-metal elements such as B, N, P, F, Cl, Br, I, Li, Na, Mg, Al, K, Ca, Zn, Ga, Ge, Sn, Sr, Ba and the like. Typical metal elements such as Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Mo, Zr, Nb, W and other transition metal elements are used as positive electrode active materials, conductive agents, binders, thickeners, fillers. It may be contained as a component other than.
（負極）
　負極は、本発明の一実施形態に係る非水電解質蓄電素子用負極である。当該負極の詳細は上述した通りである。 (Negative electrode)
The negative electrode is a negative electrode for a non-aqueous electrolyte power storage element according to an embodiment of the present invention. The details of the negative electrode are as described above.
　当該非水電解質蓄電素子は、通常使用時の充電終止電圧における負極電位の下限としては、０．３５Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）が好ましく、０．４０Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）がより好ましく、０．６０Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）がさらに好ましい。通常使用時の充電終止電圧における負極電位を上記下限以上となるように充電を行うことで、負極における金属リチウムのデンドライト状の析出を抑制できるため、急速充電が可能となる。また、負極が純アルミニウム又はアルミニウム合金からなる負極基材を有する場合には、リチウムーアルミニウム合金化反応を抑制しつつ、高容量を維持させることができる。一方、通常使用時の充電終止電圧における負極電位の上限としては、例えば１．５Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）が好ましく、１．０Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）がより好ましい。 In the non-aqueous electrolyte power storage element, the lower limit of the negative electrode potential at the end of charging voltage during normal use is preferably 0.35 V (vs. Li / Li + ), more preferably 0.40 V (vs. Li / Li + ). Preferably, 0.60 V (vs. Li / Li + ) is even more preferable. By charging so that the negative electrode potential at the end-of-charge voltage during normal use is equal to or higher than the above lower limit, dendrite-like precipitation of metallic lithium on the negative electrode can be suppressed, so that rapid charging becomes possible. Further, when the negative electrode has a negative electrode base material made of pure aluminum or an aluminum alloy, it is possible to maintain a high capacity while suppressing the lithium-aluminum alloying reaction. On the other hand, as the upper limit of the negative electrode potential in the charge termination voltage during normal use, for example, 1.5 V (vs. Li / Li + ) is preferable, and 1.0 V (vs. Li / Li + ) is more preferable.
（セパレータ）
　セパレータは、公知のセパレータの中から適宜選択できる。セパレータとして、例えば、基材層のみからなるセパレータ、基材層の一方の面又は双方の面に耐熱粒子とバインダとを含む耐熱層が形成されたセパレータ等を使用することができる。セパレータの基材層の形状としては、例えば、織布、不織布、多孔質樹脂フィルム等が挙げられる。これらの形状の中でも、強度の観点から多孔質樹脂フィルムが好ましく、非水電解質の保液性の観点から不織布が好ましい。セパレータの基材層の材料としては、シャットダウン機能の観点から例えばポリエチレン、ポリプロピレン等のポリオレフィンが好ましく、耐酸化分解性の観点から例えばポリイミドやアラミド等が好ましい。セパレータの基材層として、これらの樹脂を複合した材料を用いてもよい。 (Separator)
The separator can be appropriately selected from known separators. As the separator, for example, a separator composed of only a base material layer, a separator having a heat-resistant layer containing heat-resistant particles and a binder formed on one surface or both surfaces of the base material layer can be used. Examples of the shape of the base material layer of the separator include woven fabrics, non-woven fabrics, and porous resin films. Among these shapes, a porous resin film is preferable from the viewpoint of strength, and a non-woven fabric is preferable from the viewpoint of liquid retention of a non-aqueous electrolyte. As the material of the base material layer of the separator, polyolefins such as polyethylene and polypropylene are preferable from the viewpoint of shutdown function, and polyimide and aramid are preferable from the viewpoint of oxidative decomposition resistance. As the base material layer of the separator, a material in which these resins are combined may be used.
　耐熱層に含まれる耐熱粒子は、１気圧の空気雰囲気下で室温から５００℃まで昇温したときの質量減少が５％以下であるものが好ましく、室温から８００℃まで昇温したときの質量減少が５％以下であるものがさらに好ましい。質量減少が所定以下である材料として無機化合物が挙げられる。無機化合物として、例えば、酸化鉄、酸化ケイ素、酸化アルミニウム、酸化チタン、酸化ジルコニウム、酸化カルシウム、酸化ストロンチウム、酸化バリウム、酸化マグネシウム、アルミノケイ酸塩等の酸化物；窒化アルミニウム、窒化ケイ素等の窒化物；炭酸カルシウム等の炭酸塩；硫酸バリウム等の硫酸塩；フッ化カルシウム、フッ化バリウム、チタン酸バリウム等の難溶性のイオン結晶；シリコン、ダイヤモンド等の共有結合性結晶；タルク、モンモリロナイト、ベーマイト、ゼオライト、アパタイト、カオリン、ムライト、スピネル、オリビン、セリサイト、ベントナイト、マイカ等の鉱物資源由来物質又はこれらの人造物等が挙げられる。無機化合物として、これらの物質の単体又は複合体を単独で用いてもよく、２種以上を混合して用いてもよい。これらの無機化合物の中でも、蓄電素子の安全性の観点から、酸化ケイ素、酸化アルミニウム、又はアルミノケイ酸塩が好ましい。 The heat-resistant particles contained in the heat-resistant layer preferably have a mass reduction of 5% or less when the temperature is raised from room temperature to 500 ° C. in an air atmosphere of 1 atm, and the mass reduction when the temperature is raised from room temperature to 800 ° C. Is more preferably 5% or less. Inorganic compounds can be mentioned as materials whose mass reduction is less than or equal to a predetermined value. Examples of the inorganic compound include oxides such as iron oxide, silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, calcium oxide, strontium oxide, barium oxide, magnesium oxide and aluminosilicate; nitrides such as aluminum nitride and silicon nitride. Carbonates such as calcium carbonate; Sulfates such as barium sulfate; sparingly soluble ion crystals such as calcium fluoride, barium fluoride, barium titanate; covalent crystals such as silicon and diamond; talc, montmorillonite, boehmite, Examples thereof include mineral resource-derived substances such as zeolite, apatite, kaolin, mulite, spinel, olivine, sericite, bentonite, and mica, or man-made products thereof. As the inorganic compound, a simple substance or a complex of these substances may be used alone, or two or more kinds thereof may be mixed and used. Among these inorganic compounds, silicon oxide, aluminum oxide, or aluminosilicate is preferable from the viewpoint of safety of the power storage device.
　セパレータの空孔率は、強度の観点から８０体積％以下が好ましく、放電性能の観点から２０体積％以上が好ましい。ここで、「空孔率」とは、体積基準の値であり、水銀ポロシメータでの測定値を意味する。 The porosity of the separator is preferably 80% by volume or less from the viewpoint of strength, and preferably 20% by volume or more from the viewpoint of discharge performance. Here, the "porosity" is a volume-based value and means a measured value with a mercury porosity meter.
　セパレータとして、ポリマーと非水電解質とで構成されるポリマーゲルを用いてもよい。ポリマーとして、例えば、ポリアクリロニトリル、ポリエチレンオキシド、ポリプロピレンオキシド、ポリメチルメタアクリレート、ポリビニルアセテート、ポリビニルピロリドン、ポリフッ化ビニリデン等が挙げられる。ポリマーゲルを用いると、漏液を抑制する効果がある。セパレータとして、上述したような多孔質樹脂フィルム又は不織布等とポリマーゲルを併用してもよい。 As the separator, a polymer gel composed of a polymer and a non-aqueous electrolyte may be used. Examples of the polymer include polyacrylonitrile, polyethylene oxide, polypropylene oxide, polymethyl methacrylate, polyvinyl acetate, polyvinylpyrrolidone, polyvinylidene fluoride and the like. The use of polymer gel has the effect of suppressing liquid leakage. As the separator, a polymer gel may be used in combination with a porous resin film or a non-woven fabric as described above.
（非水電解質）
　非水電解質としては、公知の非水電解質の中から適宜選択できる。非水電解質には、非水電解液を用いてもよい。非水電解液は、非水溶媒と、この非水溶媒に溶解されている電解質塩とを含む。 (Non-water electrolyte)
As the non-aqueous electrolyte, a known non-aqueous electrolyte can be appropriately selected. A non-aqueous electrolyte solution may be used as the non-aqueous electrolyte. The non-aqueous electrolyte solution contains a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent.
　非水溶媒としては、公知の非水溶媒の中から適宜選択できる。非水溶媒としては、環状カーボネート、鎖状カーボネート、カルボン酸エステル、リン酸エステル、スルホン酸エステル、エーテル、アミド、ニトリル等が挙げられる。非水溶媒として、これらの化合物に含まれる水素原子の一部がハロゲンに置換されたものを用いてもよい。 The non-aqueous solvent can be appropriately selected from known non-aqueous solvents. Examples of the non-aqueous solvent include cyclic carbonates, chain carbonates, carboxylic acid esters, phosphoric acid esters, sulfonic acid esters, ethers, amides, nitriles and the like. As the non-aqueous solvent, a solvent in which some of the hydrogen atoms contained in these compounds are replaced with halogen may be used.
　環状カーボネートとしては、エチレンカーボネート（ＥＣ）、プロピレンカーボネート（ＰＣ）、ブチレンカーボネート（ＢＣ）、ビニレンカーボネート（ＶＣ）、ビニルエチレンカーボネート（ＶＥＣ）、クロロエチレンカーボネート、フルオロエチレンカーボネート（ＦＥＣ）、ジフルオロエチレンカーボネート（ＤＦＥＣ）、スチレンカーボネート、１－フェニルビニレンカーボネート、１，２－ジフェニルビニレンカーボネート等が挙げられる。これらの中でもＥＣ、ＰＣが好ましく、ＰＣが特に好ましい。ＰＣを用いることで優れた高率充電電気量比を示すことができる。 Examples of the cyclic carbonate include ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), vinylene carbonate (VC), vinyl ethylene carbonate (VEC), chloroethylene carbonate, fluoroethylene carbonate (FEC), and difluoroethylene carbonate. (DFEC), styrene carbonate, 1-phenylvinylene carbonate, 1,2-diphenylvinylene carbonate and the like can be mentioned. Among these, EC and PC are preferable, and PC is particularly preferable. By using a PC, it is possible to show an excellent high rate charge electricity amount ratio.
　鎖状カーボネートとしては、ジエチルカーボネート（ＤＥＣ）、ジメチルカーボネート（ＤＭＣ）、エチルメチルカーボネート（ＥＭＣ）、ジフェニルカーボネート、トリフルオロエチルメチルカーボネート、ビス（トリフルオロエチル）カーボネート等が挙げられる。これらの中でもＤＥＣ、ＥＭＣが好ましく、ＤＥＣが特に好ましい。ＤＥＣを用いることで優れた高率充電電気量比を示すことができる。 Examples of the chain carbonate include diethyl carbonate (DEC), dimethyl carbonate (DMC), ethylmethyl carbonate (EMC), diphenyl carbonate, trifluoroethylmethyl carbonate, bis (trifluoroethyl) carbonate and the like. Among these, DEC and EMC are preferable, and DEC is particularly preferable. By using DEC, it is possible to show an excellent high rate charge electricity amount ratio.
　非水溶媒として、環状カーボネート又は鎖状カーボネートを用いることが好ましく、環状カーボネートと鎖状カーボネートとを併用することがより好ましい。環状カーボネートを用いることで、電解質塩の解離を促進して非水電解液のイオン伝導度を向上させることができる。鎖状カーボネートを用いることで、非水電解液の粘度を低く抑えることができる。環状カーボネートと鎖状カーボネートとを併用する場合、環状カーボネートと鎖状カーボネートとの体積比率（環状カーボネート：鎖状カーボネート）としては、例えば、５：９５から５０：５０の範囲とすることが好ましい。 As the non-aqueous solvent, it is preferable to use cyclic carbonate or chain carbonate, and it is more preferable to use cyclic carbonate and chain carbonate in combination. By using the cyclic carbonate, the dissociation of the electrolyte salt can be promoted and the ionic conductivity of the non-aqueous electrolyte solution can be improved. By using the chain carbonate, the viscosity of the non-aqueous electrolytic solution can be kept low. When the cyclic carbonate and the chain carbonate are used in combination, the volume ratio of the cyclic carbonate to the chain carbonate (cyclic carbonate: chain carbonate) is preferably in the range of, for example, 5:95 to 50:50.
　電解質塩としては、公知の電解質塩から適宜選択できる。電解質塩としては、リチウム塩、ナトリウム塩、カリウム塩、マグネシウム塩、オニウム塩等が挙げられる。これらの中でもリチウム塩が好ましい。 The electrolyte salt can be appropriately selected from known electrolyte salts. Examples of the electrolyte salt include lithium salt, sodium salt, potassium salt, magnesium salt, onium salt and the like. Of these, lithium salts are preferred.
　リチウム塩としては、ＬｉＰＦ６、ＬｉＰＯ２Ｆ２、ＬｉＢＦ４、ＬｉＣｌＯ４、ＬｉＮ（ＳＯ２Ｆ）２等の無機リチウム塩、リチウムビス（オキサレート）ボレート（ＬｉＢＯＢ）、リチウムジフルオロオキサレートボレート（ＬｉＦＯＢ）、リチウムビス（オキサレート）ジフルオロホスフェート（ＬｉＦＯＰ）等のシュウ酸リチウム塩、ＬｉＳＯ３ＣＦ３、ＬｉＮ（ＳＯ２ＣＦ３）２、ＬｉＮ（ＳＯ２Ｃ２Ｆ５）２、ＬｉＮ（ＳＯ２ＣＦ３）（ＳＯ２Ｃ４Ｆ９）、ＬｉＣ（ＳＯ２ＣＦ３）３、ＬｉＣ（ＳＯ２Ｃ２Ｆ５）３等のハロゲン化炭化水素基を有するリチウム塩等が挙げられる。これらの中でも、無機リチウム塩が好ましく、ＬｉＰＦ６がより好ましい。 Examples of the lithium salt include inorganic lithium salts such as LiPF 6 , LiPO 2 F 2 , LiBF 4 , LiClO 4 , LiN (SO 2 F) 2 , lithium bis (oxalate) borate (LiBOB), and lithium difluorooxalate borate (LiFOB). , Lithium oxalate salts such as lithium bis (oxalate) difluorophosphate (LiFOP), LiSO 3 CF 3 , LiN (SO 2 CF 3 ) 2 , LiN (SO 2 C 2 F 5 ) 2 , LiN (SO 2 CF 3 ) Examples thereof include lithium salts having a halogenated hydrocarbon group such as (SO 2 C 4 F 9 ), LiC (SO 2 CF 3 ) 3 , and LiC (SO 2 C 2 F 5 ) 3 . Among these, an inorganic lithium salt is preferable, and LiPF 6 is more preferable.
　非水電解液における電解質塩の含有量は、２０℃１気圧下において、０．１ｍｏｌ／ｄｍ３以上２．５ｍｏｌ／ｄｍ３以下であると好ましく、０．３ｍｏｌ／ｄｍ３以上２．０ｍｏｌ／ｄｍ３以下であるとより好ましく、０．５ｍｏｌ／ｄｍ３以上１．７ｍｏｌ／ｄｍ３以下であるとさらに好ましく、０．７ｍｏｌ／ｄｍ３以上１．５ｍｏｌ／ｄｍ３以下であると特に好ましい。電解質塩の含有量を上記の範囲とすることで、非水電解液のイオン伝導度を高めることができる。 The content of the electrolyte salt in the non-aqueous electrolyte solution is preferably 0.1 mol / dm 3 or more and 2.5 mol / dm 3 or less, and 0.3 mol / dm 3 or more and 2.0 mol / dm at 20 ° C. and 1 atm. It is more preferably 3 or less, more preferably 0.5 mol / dm 3 or more and 1.7 mol / dm 3 or less, and particularly preferably 0.7 mol / dm 3 or more and 1.5 mol / dm 3 or less. By setting the content of the electrolyte salt in the above range, the ionic conductivity of the non-aqueous electrolyte solution can be increased.
　非水電解液は、非水溶媒と電解質塩以外に、添加剤を含んでもよい。添加剤としては、例えば、フルオロエチレンカーボネート（ＦＥＣ）、ジフルオロエチレンカーボネート（ＤＦＥＣ）等のハロゲン化炭酸エステル；リチウムビス（オキサレート）ボレート（ＬｉＢＯＢ）、リチウムジフルオロオキサレートボレート（ＬｉＦＯＢ）、リチウムビス（オキサレート）ジフルオロホスフェート（ＬｉＦＯＰ）等のシュウ酸塩；リチウムビス（フルオロスルホニル）イミド（ＬｉＦＳＩ）等のイミド塩；ビフェニル、アルキルビフェニル、ターフェニル、ターフェニルの部分水素化体、シクロヘキシルベンゼン、ｔ－ブチルベンゼン、ｔ－アミルベンゼン、ジフェニルエーテル、ジベンゾフラン等の芳香族化合物；２－フルオロビフェニル、ｏ－シクロヘキシルフルオロベンゼン、ｐ－シクロヘキシルフルオロベンゼン等の前記芳香族化合物の部分ハロゲン化物；２，４－ジフルオロアニソール、２，５－ジフルオロアニソール、２，６－ジフルオロアニソール、３，５－ジフルオロアニソール等のハロゲン化アニソール化合物；ビニレンカーボネート、メチルビニレンカーボネート、エチルビニレンカーボネート、無水コハク酸、無水グルタル酸、無水マレイン酸、無水シトラコン酸、無水グルタコン酸、無水イタコン酸、シクロヘキサンジカルボン酸無水物；亜硫酸エチレン、亜硫酸プロピレン、亜硫酸ジメチル、メタンスルホン酸メチル、ブスルファン、トルエンスルホン酸メチル、硫酸ジメチル、硫酸エチレン、スルホラン、ジメチルスルホン、ジエチルスルホン、ジメチルスルホキシド、ジエチルスルホキシド、テトラメチレンスルホキシド、ジフェニルスルフィド、４，４’－ビス（２，２－ジオキソ－１，３，２－ジオキサチオラン）、４－メチルスルホニルオキシメチル－２，２－ジオキソ－１，３，２－ジオキサチオラン、チオアニソール、ジフェニルジスルフィド、ジピリジニウムジスルフィド、１，３－プロペンスルトン、１，３－プロパンスルトン、１，４－ブタンスルトン、１，４－ブテンスルトン、パーフルオロオクタン、ホウ酸トリストリメチルシリル、リン酸トリストリメチルシリル、チタン酸テトラキストリメチルシリル、モノフルオロリン酸リチウム、ジフルオロリン酸リチウム等が挙げられる。これら添加剤は、１種を単独で用いてもよく、２種以上を混合して用いてもよい。 The non-aqueous electrolyte solution may contain additives in addition to the non-aqueous solvent and the electrolyte salt. Examples of the additive include halogenated carbonates such as fluoroethylene carbonate (FEC) and difluoroethylene carbonate (DFEC); lithium bis (oxalate) borate (LiBOB), lithium difluorooxalate borate (LiFOB), lithium bis (oxalate). ) Difluorophosphate (LiFOP) and other oxalates; Lithiumbis (fluorosulfonyl) imide (LiFSI) and other imide salts; biphenyl, alkylbiphenyl, terphenyl, partially hydride of turphenyl, cyclohexylbenzene, t-butylbenzene , T-Amylbenzene, diphenyl ether, dibenzofuran and other aromatic compounds; partial halides of the aromatic compounds such as 2-fluorobiphenyl, o-cyclohexylfluorobenzene, p-cyclohexylfluorobenzene; 2,4-difluoroanisole, 2 , 5-Difluoroanisole, 2,6-difluoroanisole, 3,5-difluoroanisole and other halogenated anisole compounds; vinylene carbonate, methylvinylene carbonate, ethylvinylene carbonate, succinic anhydride, glutaric anhydride, maleic anhydride, anhydrous. Citraconic acid, glutaconic anhydride, itaconic anhydride, cyclohexanedicarboxylic acid anhydride; ethylene sulfite, propylene sulfite, dimethyl sulfite, methyl methanesulfonate, busulfane, methyl toluenesulfonate, dimethyl sulfate, ethylene sulfate, sulfolane, dimethylsulfone, diethyl. Sulfon, dimethylsulfoxide, diethylsulfoxide, tetramethylenesulfoxide, diphenylsulfide, 4,4'-bis (2,2-dioxo-1,3,2-dioxathiolane), 4-methylsulfonyloxymethyl-2,2-dioxo- 1,3,2-dioxathiolane, thioanisol, diphenyldisulfide, dipyridinium disulfide, 1,3-propensulton, 1,3-propanesulton, 1,4-butanesulton, 1,4-butensulton, perfluorooctane, boric acid Examples thereof include tristrimethylsilyl, tristrimethylsilyl phosphate, tetrakistrimethylsilyl titanate, lithium monofluorophosphate, lithium difluorophosphate and the like. These additives may be used alone or in combination of two or more.
　非水電解液に含まれる添加剤の含有量は、非水電解液全体の質量に対して０．０１質量％以上１０質量％以下であると好ましく、０．１質量％以上７質量％以下であるとより好ましく、０．２質量％以上５質量％以下であるとさらに好ましく、０．３質量％以上３質量％以下であると特に好ましい。添加剤の含有量を上記の範囲とすることで、高温保存後の容量維持性能又はサイクル性能を向上させたり、安全性をより向上させたりすることができる。 The content of the additive contained in the non-aqueous electrolytic solution is preferably 0.01% by mass or more and 10% by mass or less, and is 0.1% by mass or more and 7% by mass or less with respect to the total mass of the non-aqueous electrolytic solution. It is more preferable to have it, more preferably 0.2% by mass or more and 5% by mass or less, and particularly preferably 0.3% by mass or more and 3% by mass or less. By setting the content of the additive in the above range, it is possible to improve the capacity maintenance performance or the cycle performance after high temperature storage, and further improve the safety.
　非水電解質には、固体電解質を用いてもよく、非水電解液と固体電解質とを併用してもよい。 As the non-aqueous electrolyte, a solid electrolyte may be used, or a non-aqueous electrolyte solution and a solid electrolyte may be used in combination.
　固体電解質としては、リチウム、ナトリウム、カルシウム等のイオン伝導性を有し、常温（例えば１５℃から２５℃）において固体である任意の材料から選択できる。固体電解質としては、例えば、硫化物固体電解質、酸化物固体電解質、及び酸窒化物固体電解質、ポリマー固体電解質、ゲルポリマー電解質等が挙げられる。 The solid electrolyte can be selected from any material having ionic conductivity such as lithium, sodium and calcium and being solid at room temperature (for example, 15 ° C to 25 ° C). Examples of the solid electrolyte include sulfide solid electrolytes, oxide solid electrolytes, oxynitride solid electrolytes, polymer solid electrolytes, gel polymer electrolytes and the like.
　硫化物固体電解質としては、リチウムイオン二次電池の場合、例えばＬｉ２Ｓ－Ｐ２Ｓ５、ＬｉＩ－Ｌｉ２Ｓ－Ｐ２Ｓ５、Ｌｉ１０Ｇｅ－Ｐ２Ｓ１２等が挙げられる。 Examples of the lithium ion secondary battery include Li 2 SP 2 S 5, Li I-Li 2 SP 2 S 5 , Li 10 Ge -P 2 S 12 and the like as the sulfide solid electrolyte.
（非水電解質蓄電素子の具体的構成）
　本実施形態の非水電解質蓄電素子の形状については特に限定されるものではなく、例えば、円筒型電池、角型電池、扁平型電池、コイン型電池、ボタン型電池等が挙げられる。 (Specific configuration of non-aqueous electrolyte power storage element)
The shape of the non-aqueous electrolyte power storage element of the present embodiment is not particularly limited, and examples thereof include a cylindrical battery, a square battery, a flat battery, a coin battery, and a button battery.
　図１に角型電池の一例としての非水電解質蓄電素子１を示す。なお、同図は、容器内部を透視した図としている。セパレータを挟んで巻回された正極及び負極を有する電極体２が角型の容器３に収納される。正極は正極リード４１を介して正極端子４と電気的に接続されている。負極は負極リード５１を介して負極端子５と電気的に接続されている。本実施形態の非水電解質蓄電素子の構造については特に限定されるものではなく、図１に示した構造以外にも、例えばバイポーラ構造に適用することができる。 FIG. 1 shows a non-aqueous electrolyte power storage element 1 as an example of a square battery. The figure is a perspective view of the inside of the container. The electrode body 2 having the positive electrode and the negative electrode wound around the separator is housed in the square container 3. The positive electrode is electrically connected to the positive electrode terminal 4 via the positive electrode lead 41. The negative electrode is electrically connected to the negative electrode terminal 5 via the negative electrode lead 51. The structure of the non-aqueous electrolyte power storage element of the present embodiment is not particularly limited, and can be applied to, for example, a bipolar structure other than the structure shown in FIG.
（蓄電装置の構成）
　本実施形態の蓄電装置は、非水電解質蓄電素子を二以上備え、且つ本実施形態の非水電解質蓄電素子を一以上備える。当該蓄電素子は、当該非水電解質蓄電素子を一以上備えるので、比較的貴な電位領域における質量あたりの放電容量及びクーロン効率を高めることができる。本実施形態の非水電解質蓄電素子は、電気自動車（ＥＶ）、ハイブリッド自動車（ＨＥＶ）、プラグインハイブリッド自動車（ＰＨＥＶ）等の自動車用電源、パーソナルコンピュータ、通信端末等の電子機器用電源、又は電力貯蔵用電源等に、複数の非水電解質蓄電素子１を集合して構成した蓄電装置として搭載することができる。この場合、蓄電装置に含まれる少なくとも一つの非水電解質蓄電素子に対して、本発明の技術が適用されていればよい。
　図２に、電気的に接続された二以上の非水電解質蓄電素子１が集合した蓄電ユニット２０をさらに集合した蓄電装置３０の一例を示す。蓄電装置３０は、二以上の非水電解質蓄電素子１を電気的に接続するバスバ（図示せず）、二以上の蓄電ユニット２０を電気的に接続するバスバ（図示せず）等を備えていてもよい。蓄電ユニット２０又は蓄電装置３０は、一以上の非水電解質蓄電素子の状態を監視する状態監視装置（図示せず）を備えていてもよい。 (Configuration of power storage device)
The power storage device of the present embodiment includes two or more non-aqueous electrolyte power storage elements and one or more non-water electrolyte power storage elements of the present embodiment. Since the power storage element includes one or more non-aqueous electrolyte power storage elements, it is possible to increase the discharge capacity per mass and the Coulomb efficiency in a relatively noble potential region. The non-aqueous electrolyte power storage element of the present embodiment is a power source for automobiles such as an electric vehicle (EV), a hybrid vehicle (HEV), and a plug-in hybrid vehicle (PHEV), a power source for electronic devices such as a personal computer and a communication terminal, or a power source. It can be mounted on a storage power source or the like as a power storage device configured by assembling a plurality of non-aqueous electrolyte power storage elements 1. In this case, the technique of the present invention may be applied to at least one non-aqueous electrolyte power storage element included in the power storage device.
FIG. 2 shows an example of a power storage device 30 in which a power storage unit 20 in which two or more electrically connected non-aqueous electrolyte power storage elements 1 are assembled is further assembled. The power storage device 30 includes a bus bar (not shown) for electrically connecting two or more non-aqueous electrolyte power storage elements 1, a bus bar (not shown) for electrically connecting two or more power storage units 20 and the like. May be good. The power storage unit 20 or the power storage device 30 may include a condition monitoring device (not shown) for monitoring the state of one or more non-aqueous electrolyte power storage elements.
（非水電解質蓄電素子の製造方法）
　本実施形態の非水電解質蓄電素子は、負極として当該負極を準備することを備える以外は、公知の方法により製造することができる。当該製造方法は、例えば、電極体を準備することと、非水電解質を準備することと、電極体及び非水電解質を容器に収容することと、を備える。電極体を準備することは、正極及び負極を準備することと、セパレータを介して正極及び負極を積層又は巻回することにより電極体を形成することとを備える。 (Manufacturing method of non-aqueous electrolyte power storage element)
The non-aqueous electrolyte power storage device of the present embodiment can be manufactured by a known method except that the negative electrode is prepared as a negative electrode. The manufacturing method includes, for example, preparing an electrode body, preparing a non-aqueous electrolyte, and accommodating the electrode body and the non-aqueous electrolyte in a container. Preparing the electrode body includes preparing the positive electrode body and the negative electrode body, and forming the electrode body by laminating or winding the positive electrode body and the negative electrode body via the separator.
　非水電解質を容器に収容することは、公知の方法から適宜選択できる。例えば、非水電解質に非水電解液を用いる場合、容器に形成された注入口から非水電解液を注入した後、注入口を封止すればよい。 The storage of the non-aqueous electrolyte in the container can be appropriately selected from known methods. For example, when a non-aqueous electrolyte solution is used as the non-aqueous electrolyte solution, the non-aqueous electrolyte solution may be injected from the injection port formed in the container, and then the injection port may be sealed.
＜その他の実施形態＞
　なお、本発明の非水電解質蓄電素子は、上記実施形態に限定されるものではなく、本発明の要旨を逸脱しない範囲内において種々変更を加えてもよい。例えば、ある実施形態の構成に他の実施形態の構成を追加することができ、また、ある実施形態の構成の一部を他の実施形態の構成又は周知技術に置き換えることができる。さらに、ある実施形態の構成の一部を削除することができる。また、ある実施形態の構成に対して周知技術を付加することができる。 <Other embodiments>
The non-aqueous electrolyte power storage device of the present invention is not limited to the above embodiment, and various modifications may be made without departing from the gist of the present invention. For example, the configuration of one embodiment can be added to the configuration of another embodiment, and a part of the configuration of one embodiment can be replaced with the configuration of another embodiment or a well-known technique. In addition, some of the configurations of certain embodiments can be deleted. Further, a well-known technique can be added to the configuration of a certain embodiment.
　上記実施形態では、非水電解質蓄電素子が充放電可能な非水電解質二次電池（例えばリチウムイオン二次電池）として用いられる場合について説明したが、非水電解質蓄電素子の種類、形状、寸法、容量等は任意である。本発明は、種々の二次電池、電気二重層キャパシタ又はリチウムイオンキャパシタ等のキャパシタにも適用できる。 In the above embodiment, the case where the non-aqueous electrolyte storage element is used as a chargeable / dischargeable non-aqueous electrolyte secondary battery (for example, a lithium ion secondary battery) has been described. The capacity etc. are arbitrary. The present invention can also be applied to capacitors such as various secondary batteries, electric double layer capacitors and lithium ion capacitors.
　以下、実施例によって本発明をさらに具体的に説明する。本発明は以下の実施例に限定されない。 Hereinafter, the present invention will be described in more detail by way of examples. The present invention is not limited to the following examples.
［実施例１］
　基材である黒鉛シートＰＦ１１０をＭＰＣＶＤ－Ｐｏｗｄｅｒ（ＭＩＣＲＯＰＨＡＳＥ社製）（以下、小型ＣＶＤ装置ともいう）の石英管（内径４５ｍｍ）の中に設置した。窒素気流下、昇温速度１０℃／分にて基材を設置した付近の石英管を常温から１０００℃に昇温した。１０００℃に到達してから、表１に示したガス比で原料ガス及びキャリアガスを石英管中に流し、化学気相成長（ＣＶＤ）法により５時間かけて炭素材料を基材上に析出させた。その後、原料ガスの導入を止めて、１０００℃から常温まで放冷し、石英管から基材を取り出した。基材から析出した炭素材料を回収した。この炭素材料を容積３０ｍＬのアルミナ製るつぼに入れ、卓上真空ガス置換炉ＫＤＦ７５（デンケン・ハイデンタル社製）内に設置した。次いで、０．５Ｌ／分の窒素気流下、常圧にて、昇温速度５℃／分にて常温から９００℃に昇温し、１時間保持して、再熱処理を施した。そして、再熱処理後にアルミナ製乳鉢で粉砕を施した炭素材料を実施例１とした。 [Example 1]
The graphite sheet PF110 as a base material was installed in a quartz tube (inner diameter 45 mm) of MPCVD-Powder (manufactured by MICROPHASE) (hereinafter, also referred to as a small CVD device). Under a nitrogen stream, the temperature of the quartz tube near the substrate was raised from room temperature to 1000 ° C. at a temperature rise rate of 10 ° C./min. After reaching 1000 ° C., the raw material gas and the carrier gas were flowed into the quartz tube at the gas ratios shown in Table 1, and the carbon material was deposited on the substrate over 5 hours by the chemical vapor deposition (CVD) method. rice field. Then, the introduction of the raw material gas was stopped, the mixture was allowed to cool from 1000 ° C. to room temperature, and the base material was taken out from the quartz tube. The carbon material precipitated from the substrate was recovered. This carbon material was placed in an alumina crucible having a volume of 30 mL and installed in a tabletop vacuum gas replacement furnace KDF75 (manufactured by Denken Hydental). Then, the temperature was raised from normal temperature to 900 ° C. at a heating rate of 5 ° C./min at normal pressure under a nitrogen stream of 0.5 L / min, held for 1 hour, and reheat-treated. Then, the carbon material which was pulverized with an alumina mortar after the reheat treatment was designated as Example 1.
［実施例２］
　実施例１のＣＶＤ法による炭素材料合成後、基材を取り出した後に、石英管内に残った炭素材料を回収し、アルミナ製乳鉢で粉砕を施し、実施例２とした。 [Example 2]
After synthesizing the carbon material by the CVD method of Example 1, after taking out the base material, the carbon material remaining in the quartz tube was recovered and pulverized in an alumina mortar to obtain Example 2.
［実施例３］
　表１に記載の条件で行った以外は実施例２と同様の工程を行なった炭素材料を回収後、実施例１と同様に再熱処理を施した。そして、再熱処理後にアルミナ製乳鉢で粉砕を施した炭素材料を実施例３とした。 [Example 3]
After recovering the carbon material that had undergone the same steps as in Example 2 except that the conditions shown in Table 1 were performed, reheat treatment was performed in the same manner as in Example 1. Then, the carbon material which was pulverized in the alumina mortar after the reheat treatment was referred to as Example 3.
［実施例４、実施例５、実施例７から実施例１０、実施例１３、実施例１５、実施例１８、実施例２０、実施例２３、実施例２５、実施例２７、実施例３５及び比較例３］
　実施例４、実施例５、実施例７から実施例１０、実施例１３、実施例１５、実施例１８、実施例２０、実施例２３、実施例２５、実施例２７、実施例３５及び比較例３について、表１に記載の条件で行った以外は実施例３と同様に合成した。 [Example 4, Example 5, Example 7 to Example 10, Example 13, Example 15, Example 18, Example 20, Example 23, Example 25, Example 27, Example 35 and comparison Example 3]
Example 4, Example 5, Example 7 to Example 10, Example 13, Example 15, Example 18, Example 20, Example 23, Example 25, Example 27, Example 35 and Comparative Example. No. 3 was synthesized in the same manner as in Example 3 except that it was carried out under the conditions shown in Table 1.
［実施例６、実施例１１、実施例１２、実施例１４、実施例１６、実施例１７、実施例１９、実施例２１、実施例２２、実施例２４、実施例２６、実施例３４及び比較例１］
　実施例６、実施例１１、実施例１２、実施例１４、実施例１６、実施例１７、実施例１９、実施例２１、実施例２２、実施例２４、実施例２６、実施例３４及び比較例１について、表１に記載の条件で行った以外は実施例１と同様に合成した。 [Example 6, Example 11, Example 12, Example 14, Example 16, Example 17, Example 19, Example 21, Example 22, Example 24, Example 26, Example 34 and comparison. Example 1]
Example 6, Example 11, Example 12, Example 14, Example 16, Example 17, Example 19, Example 21, Example 22, Example 24, Example 26, Example 34 and Comparative Example. No. 1 was synthesized in the same manner as in Example 1 except that it was carried out under the conditions shown in Table 1.
［実施例３０から実施例３３］
　炭素材料に施す粉砕を、表５に記載の条件でボールミルにて行った以外は実施例１と同様にして得た炭素材料を実施例３０から実施例３３とした。ボールミルの処理時間は８時間とした。 [Examples 30 to 33]
The carbon materials obtained in the same manner as in Example 1 except that the carbon material was pulverized by a ball mill under the conditions shown in Table 5 were designated as Examples 30 to 33. The processing time of the ball mill was 8 hours.
［実施例３６］
　基材である黒鉛シートＰＦ１１０を大型ＣＶＤ装置の石英管（内径９４ｍｍ、長さ１２００ｍｍ）の中に設置し、表１に記載の条件で行った以外は実施例１と同様に合成した。 [Example 36]
The graphite sheet PF110 as a base material was placed in a quartz tube (inner diameter 94 mm, length 1200 mm) of a large CVD apparatus, and synthesized in the same manner as in Example 1 except that the conditions shown in Table 1 were used.
［実施例３７］
　基材である黒鉛シートＰＦ１１０を大型ＣＶＤ装置の石英管（内径９４ｍｍ、長さ１２００ｍｍ）の中に設置し、表１に記載の条件で行った以外は実施例３と同様に合成した。 [Example 37]
The graphite sheet PF110 as a base material was placed in a quartz tube (inner diameter 94 mm, length 1200 mm) of a large CVD apparatus, and synthesized in the same manner as in Example 3 except that the conditions shown in Table 1 were used.
［比較例２］
　表１に記載の条件で行った以外は、実施例２と同様の工程を行なった炭素材料を回収後、この炭素材料をアルミナ製ボート（長さ１２５ｍｍ、幅３４ｍｍ）に入れ、ガス雰囲気管状炉（タナカテック社製）のアルミナ製炉心管（長さ８００ｍｍ、直径４２ｍｍ）内に設置した。次いで、０．１Ｌ／分の窒素気流下、常圧にて、昇温速度５℃／分にて常温から１３００℃に昇温し、１時間保持して、再熱処理を施した。そして、再熱処理後にアルミナ製乳鉢で粉砕を施した炭素材料を比較例２とした。 [Comparative Example 2]
After recovering the carbon material that had undergone the same steps as in Example 2 except that the conditions shown in Table 1 were performed, the carbon material was placed in an alumina boat (length 125 mm, width 34 mm) and placed in a gas atmosphere tube furnace. It was installed in an alumina core tube (length 800 mm, diameter 42 mm) manufactured by Tanaka Tech. Then, the temperature was raised from normal temperature to 1300 ° C. at a heating rate of 5 ° C./min at a normal pressure under a nitrogen stream of 0.1 L / min, held for 1 hour, and reheat-treated. Then, the carbon material which was pulverized in an alumina mortar after the reheat treatment was designated as Comparative Example 2.
［比較例４］
　コールタールピッチＭＣＰ－１１０Ｃ（ＪＦＥケミカル社製）をアルミナ製のボートに入れ、ＭＰＣＶＤ－Ｐｏｗｄｅｒ（ＭＩＣＲＯＰＨＡＳＥ社製）の石英管（内径４５ｍｍ）の中に設置した。窒素気流下、昇温速度５℃／分にてボートを設置した付近の石英管を常温から１０００℃に昇温した。１０００℃に到達してから、表１に示したガス比で原料ガス及びキャリアガスを石英管中に流し、２時間熱処理を施した。その後、原料ガスの導入を止めて、１０００℃から常温まで放冷し、石英管からボートを取り出した。ボート上の炭素材料を容積３０ｍＬのアルミナ製るつぼに入れ、卓上真空ガス置換炉ＫＤＦ７５（デンケン・ハイデンタル社製）内に設置した。次いで、０．５Ｌ／分の窒素気流下、常圧にて、昇温速度５℃／分にて常温から９００℃に昇温し、１時間保持して、再熱処理を施した。そして、再熱処理後にアルミナ製乳鉢で粉砕を施した炭素材料を比較例４とした。 [Comparative Example 4]
Coal tar pitch MCP-110C (manufactured by JFE Chemical Co., Ltd.) was placed in an alumina boat and installed in a quartz tube (inner diameter 45 mm) of MPCVD-Powder (manufactured by MICROPHASE). Under a nitrogen stream, the temperature of the quartz tube near the boat was raised from room temperature to 1000 ° C at a temperature rise rate of 5 ° C / min. After reaching 1000 ° C., the raw material gas and the carrier gas were passed through the quartz tube at the gas ratios shown in Table 1 and heat-treated for 2 hours. After that, the introduction of the raw material gas was stopped, the boat was allowed to cool from 1000 ° C. to room temperature, and the boat was taken out from the quartz tube. The carbon material on the boat was placed in an alumina crucible having a volume of 30 mL and installed in a tabletop vacuum gas replacement furnace KDF75 (manufactured by Denken Hydental). Then, the temperature was raised from normal temperature to 900 ° C. at a heating rate of 5 ° C./min at normal pressure under a nitrogen stream of 0.5 L / min, held for 1 hour, and reheat-treated. Then, the carbon material pulverized in an alumina mortar after reheat treatment was designated as Comparative Example 4.
［比較例５］
　鱗片状黒鉛（Ｄ５０＝８．８μｍ）３ｇを、発煙硝酸（Ｗａｋｏ社製）２５ｍＬ中に入れた。その懸濁液を６０℃に加熱し、マグネチックスターラーにより３００ｒｐｍで撹拌しながら塩素酸カリウム（Ｗａｋｏ社製）１０ｇを少しずつ加えた。つぎに、６０℃で３時間反応させた後、水７５０ｍＬ中に投入して反応を停止させた。得られた懸濁液について、吸引ろ過により液を分離し、水で洗浄後に６０℃で一晩乾燥し、酸化黒鉛を得た。得られた酸化黒鉛４ｇを入れたアルミナ製るつぼを卓上真空ガス置換炉ＫＤＦ７５（デンケン・ハイデンタル社製）に設置した。次いで、０．６Ｌ／分の窒素気流下、常圧にて、昇温速度１℃／分にて常温から１７０℃まで昇温し、さらに昇温速度０．１℃／分にて１７０℃から２５０℃まで昇温した後、常温まで放冷した．得られた予備熱処理後の酸化黒鉛を基材である黒鉛シートＰＦ１１０上に置き、その基材をＭＰＣＶＤ－Ｐｏｗｄｅｒ（ＭＩＣＲＯＰＨＡＳＥ社製）の石英管（内径４５ｍｍ）の中に設置した。窒素気流下、昇温速度５℃／分にて基材を設置した付近の石英管を常温から１０００℃に昇温した。１０００℃に到達してから、表１に示したガス比で原料ガス及びキャリアガスを石英管中に流し、２時間熱処理を施した。その後、原料ガスの導入を止めて、１０００℃から常温まで放冷し、石英管から基材を取り出した。基材から炭素材料を回収した。この炭素材料を容積３０ｍＬのアルミナ製るつぼに入れ、卓上真空ガス置換炉ＫＤＦ７５（デンケン・ハイデンタル社製）内に設置した。次いで、０．５Ｌ／分の窒素気流下、常圧にて、昇温速度５℃／分にて常温から９００℃に昇温し、１時間保持して、再熱処理を施した。そして、再熱処理後にアルミナ製乳鉢で粉砕を施した炭素材料を比較例５とした。 [Comparative Example 5]
3 g of scaly graphite (D50 = 8.8 μm) was placed in 25 mL of fuming nitric acid (manufactured by Wako). The suspension was heated to 60 ° C., and 10 g of potassium chlorate (manufactured by Wako) was added little by little while stirring at 300 rpm with a magnetic stirrer. Next, after reacting at 60 ° C. for 3 hours, the reaction was stopped by putting it in 750 mL of water. The obtained suspension was separated by suction filtration, washed with water, and dried at 60 ° C. overnight to obtain graphite oxide. An alumina crucible containing 4 g of the obtained graphite oxide was installed in a tabletop vacuum gas replacement furnace KDF75 (manufactured by Denken Hydental Co., Ltd.). Next, the temperature was raised from normal temperature to 170 ° C. at a heating rate of 1 ° C./min at a normal pressure under a nitrogen stream of 0.6 L / min, and further from 170 ° C. at a heating rate of 0.1 ° C./min. After raising the temperature to 250 ° C., the mixture was allowed to cool to room temperature. The obtained graphite oxide after the preliminary heat treatment was placed on a graphite sheet PF110 as a base material, and the base material was placed in a quartz tube (inner diameter 45 mm) of MPCVD-Powder (manufactured by MICROPHASE). Under a nitrogen stream, the temperature of the quartz tube near the substrate was raised from room temperature to 1000 ° C. at a heating rate of 5 ° C./min. After reaching 1000 ° C., the raw material gas and the carrier gas were passed through the quartz tube at the gas ratios shown in Table 1 and heat-treated for 2 hours. Then, the introduction of the raw material gas was stopped, the mixture was allowed to cool from 1000 ° C. to room temperature, and the base material was taken out from the quartz tube. The carbon material was recovered from the substrate. This carbon material was placed in an alumina crucible having a volume of 30 mL and installed in a tabletop vacuum gas replacement furnace KDF75 (manufactured by Denken Hydental). Then, the temperature was raised from normal temperature to 900 ° C. at a heating rate of 5 ° C./min at normal pressure under a nitrogen stream of 0.5 L / min, held for 1 hour, and reheat-treated. Then, the carbon material which was pulverized with an alumina mortar after the reheat treatment was designated as Comparative Example 5.
［参考例１、参考例２及び参考例５］
　表１に記載の試料をそのまま用いた。 [Reference Example 1, Reference Example 2 and Reference Example 5]
The samples shown in Table 1 were used as they were.
［参考例３］
　表１に記載の条件で行った以外は、比較例４と同様にして炭素材料を得た。 [Reference Example 3]
A carbon material was obtained in the same manner as in Comparative Example 4 except that the conditions shown in Table 1 were obtained.
［参考例４］
　表１に記載の条件で行った以外は、比較例５と同様にして炭素材料を得た。 [Reference example 4]
A carbon material was obtained in the same manner as in Comparative Example 5, except that the conditions shown in Table 1 were obtained.
（負極の作製）
　実施例１から実施例２７、実施例３０から実施例３７、比較例１から比較例５及び参考例１から参考例５に係る炭素材料を負極活物質として用い、次の手順で負極を作製した。バインダとしてポリフッ化ビニリデン（ＰＶＤＦ）を用いた。上記負極活物質及び上記バインダを８８：１２の質量比で含有し、Ｎ－メチルピロリドンを分散媒とする負極合剤ペーストを作製した。負極基材として厚さ２０μｍの銅箔上に、負極合剤ペーストを塗布、乾燥、プレスし、負極基材上に負極活物質層が配された非水電解質蓄電素子用負極を作製した。なお、上記負極を作用極とし、金属リチウムを対極として備える非水電解質蓄電素子の後述する充放電条件での初期電気化学特性は、アルミニウム箔を負極基材に用いた負極を作用極とし、金属リチウムを対極として備える非水電解質蓄電素子の初期電気化学特性と同等である。 (Manufacturing of negative electrode)
The carbon material according to Example 1 to Example 27, Example 30 to Example 37, Comparative Example 1 to Comparative Example 5, and Reference Example 1 to Reference Example 5 was used as the negative electrode active material, and a negative electrode was prepared by the following procedure. .. Polyvinylidene fluoride (PVDF) was used as the binder. A negative electrode mixture paste containing the negative electrode active material and the binder in a mass ratio of 88:12 and using N-methylpyrrolidone as a dispersion medium was prepared. A negative electrode mixture paste was applied, dried, and pressed on a copper foil having a thickness of 20 μm as a negative electrode base material to prepare a negative electrode for a non-aqueous electrolyte power storage element in which a negative electrode active material layer was arranged on the negative electrode base material. The initial electrochemical characteristics of the non-aqueous electrolyte power storage element having the negative electrode as the working electrode and the metallic lithium as the counter electrode under the charge / discharge conditions described later are such that the negative electrode using the aluminum foil as the negative electrode base material is the working electrode and the metal. It is equivalent to the initial electrochemical characteristics of the non-aqueous electrolyte power storage element having lithium as the counter electrode.
（非水電解質蓄電素子の作製）
　上記非水電解質蓄電素子用負極の性能を評価するため、幅３０ｍｍ、長さ４０ｍｍの矩形状に負極活物質層が配された上記非水電解質蓄電素子用負極を作用極として、評価試験用の非水電解質蓄電素子を作製した。対極には幅３２ｍｍ、長さ４２ｍｍの矩形状の金属リチウムを用いた。セパレータにはポリエチレン製の微多孔膜を用いた。非水電解質としては、エチレンカーボネート（ＥＣ）：ジメチルカーボネート（ＤＭＣ）：エチルメチルカーボネート（ＥＭＣ）が体積比３０：３５：３５で混合された混合溶媒に１ｍｏｌ／ｄｍ３の濃度でＬｉＰＦ６を溶解させた溶液を用いた。上記セパレータを介して、上記作用極と対極を対向させ、上記の非水電解質を注入したパウチセルを作製した。これにより実施例１から実施例２７、実施例３０から実施例３７、比較例１から比較例５及び参考例１から参考例５の非水電解質蓄電素子を得た。 (Manufacturing of non-aqueous electrolyte power storage element)
In order to evaluate the performance of the negative electrode for the non-aqueous electrolyte power storage element, the negative electrode for the non-aqueous electrolyte power storage element in which the negative electrode active material layer is arranged in a rectangular shape having a width of 30 mm and a length of 40 mm is used as a working electrode for an evaluation test. A non-aqueous electrolyte power storage element was manufactured. A rectangular metallic lithium having a width of 32 mm and a length of 42 mm was used as the counter electrode. A polyethylene microporous membrane was used as the separator. As a non-aqueous electrolyte, LiPF 6 is dissolved in a mixed solvent in which ethylene carbonate (EC): dimethyl carbonate (DMC): ethylmethyl carbonate (EMC) is mixed at a volume ratio of 30:35:35 at a concentration of 1 mol / dm 3 . The solution was used. A pouch cell infused with the non-aqueous electrolyte was prepared by facing the working electrode and the counter electrode through the separator. As a result, the non-aqueous electrolyte power storage elements of Example 1 to Example 27, Example 30 to Example 37, Comparative Example 1 to Comparative Example 5, and Reference Example 1 to Reference Example 5 were obtained.
［実施例３８から実施例４２］
　非水電解質組成を表７に記載のとおりとした以外は、実施例１と同様にして非水電解質蓄電素子を得た。 [Examples 38 to 42]
A non-aqueous electrolyte power storage device was obtained in the same manner as in Example 1 except that the non-aqueous electrolyte composition was as shown in Table 7.
［実施例２８］
　実施例２８に係る炭素材料を負極活物質として用い、上記負極活物質、導電剤としてのカーボンナノチューブ、バインダとしてのスチレンブタジエンゴム及び増粘剤としてのカルボキシメチルセルロースを９６．６：０．１：２．１：１．２の質量比で含有し、水を分散媒とする負極合剤ペーストを作製し、負極基材に厚さ２０μｍのアルミニウム箔を用いた以外は実施例２２と同様にして実施例２８の非水電解質蓄電素子を得た。 [Example 28]
Using the carbon material according to Example 28 as the negative electrode active material, the negative electrode active material, carbon nanotube as a conductive agent, styrene butadiene rubber as a binder, and carboxymethyl cellulose as a thickener are 96.6: 0.1: 2. A negative electrode mixture paste containing a mass ratio of 1: 1.2 and using water as a dispersion medium was prepared, and the same procedure as in Example 22 was carried out except that an aluminum foil having a thickness of 20 μm was used as the negative electrode base material. The non-aqueous electrolyte power storage element of Example 28 was obtained.
［実施例２９］
　実施例２９に係る炭素材料を負極活物質として用い、上記負極活物質、バインダとしてのスチレンブタジエンゴム及び増粘剤としてのカルボキシメチルセルロースを９６．７：２．１：１．２の質量比で含有し、水を分散媒とする負極合剤ペーストを作製し、負極基材に厚さ２０μｍのアルミニウム箔を用いた以外は実施例２２と同様にして実施例２９の非水電解質蓄電素子を得た。 [Example 29]
The carbon material according to Example 29 is used as the negative electrode active material, and the negative electrode active material, styrene-butadiene rubber as a binder, and carboxymethyl cellulose as a thickener are contained in a mass ratio of 96.7: 2.1: 1.2. Then, a negative electrode mixture paste using water as a dispersion medium was prepared, and a non-aqueous electrolyte power storage element of Example 29 was obtained in the same manner as in Example 22 except that an aluminum foil having a thickness of 20 μm was used as the negative electrode base material. ..
　実施例１から実施例２７、実施例３０から実施例３７、比較例１から比較例５及び参考例１から参考例４の非水電解質蓄電素子に対して、以下の手順及び条件にて初期放電容量確認試験を行った。温度は全て２５℃にて行った。 Initial discharge to the non-aqueous electrolyte power storage elements of Example 1 to Example 27, Example 30 to Example 37, Comparative Example 1 to Comparative Example 5, and Reference Example 1 to Reference Example 4 according to the following procedure and conditions. A capacity confirmation test was conducted. All temperatures were 25 ° C.
（初期充放電）
　得られた各非水電解液蓄電素子について、２５℃にて、以下の条件にて２サイクルの初期充放電を行った。充電は、負極活物質１ｇ当たり５０ｍＡの充電電流で、充電終止電圧０．４Ｖの定電流定電圧（ＣＣＣＶ）充電とし、充電終止条件は、定電圧充電が開始してから１２時間経過した時点とした。放電は、負極活物質１ｇ当たり５０ｍＡの放電電流で、放電終止電圧２．０Ｖの定電流（ＣＣ）放電とした。充電後及び放電後にはそれぞれ１０分間の休止期間を設けた。２サイクル目の放電容量を負極活物質の質量で除し、「初期放電容量［ｍＡｈｇ－１］」とした。 (Initial charge / discharge)
Each of the obtained non-aqueous electrolyte storage elements was initially charged and discharged for two cycles at 25 ° C. under the following conditions. Charging is a constant current constant voltage (CCCV) charge with a charge current of 50 mA per 1 g of the negative electrode active material, and the charge end condition is 12 hours after the start of the constant voltage charge. did. The discharge was a constant current (CC) discharge with a discharge end voltage of 2.0 V with a discharge current of 50 mA per 1 g of the negative electrode active material. A 10-minute rest period was provided after charging and discharging. The discharge capacity in the second cycle was divided by the mass of the negative electrode active material to obtain "initial discharge capacity [mAhg -1 ]".
（クーロン効率）
　上記初期充放電の１サイクル目の充電電気量に対する１サイクル目の放電容量の百分率を「クーロン効率（％）」とした。 (Coulomb efficiency)
The percentage of the discharge capacity in the first cycle to the charge electricity amount in the first cycle of the initial charge / discharge was defined as "Coulomb efficiency (%)".
（全ホウ素含有量の測定）
　上記実施例１から実施例２９、比較例１から比較例５及び参考例３から参考例５に係る負極活物質の全ホウ素含有量（質量％）について、以下の手順にてＩＣＰにより測定を行った。始めに、マイクロ波分解法により、負極活物質を硝酸中に全溶解させた。次に、この溶液を純水で一定量にメスアップし、測定溶液とした。そして、マルチ型ＩＣＰ発光分光分析装置ＩＣＰＥ－９８２０（島津製作所社製）を用い、ＩＣＰ発光分光分析により上記測定溶液のホウ素濃度を測定した。得られたホウ素濃度から、負極活物質中の全ホウ素含有量を定量した。なお、上記測定溶液のホウ素濃度の算出においては、既知のホウ素濃度の溶液から検量線を作成し、上記測定溶液のホウ素濃度を求める検量線法を用いた。 (Measurement of total boron content)
The total boron content (mass%) of the negative electrode active material according to Example 1 to Example 29, Comparative Example 1 to Comparative Example 5, and Reference Example 3 to Reference Example 5 was measured by ICP according to the following procedure. rice field. First, the negative electrode active material was completely dissolved in nitric acid by the microwave decomposition method. Next, this solution was made up to a certain amount with pure water to prepare a measurement solution. Then, the boron concentration of the above-mentioned measurement solution was measured by ICP emission spectroscopic analysis using a multi-type ICP emission spectroscopic analyzer ICPE-9820 (manufactured by Shimadzu Corporation). From the obtained boron concentration, the total boron content in the negative electrode active material was quantified. In calculating the boron concentration of the measurement solution, a calibration curve method was used in which a calibration curve was prepared from a solution having a known boron concentration and the boron concentration of the measurement solution was obtained.
（ＸＰＳ測定）
　上記実施例１から実施例２９、比較例１から比較例５及び参考例５に係る負極活物質について、上記測定方法にてＸＰＳ測定を行った。 (XPS measurement)
XPS measurements were performed on the negative electrode active materials according to Examples 1 to 29 and Comparative Examples 1 to 5 and Reference Example 5 by the above measuring method.
（ホウ素－炭素結合を形成するホウ素の含有量）
　上記実施例１から実施例２９及び比較例１から比較例５に係る負極活物質について、炭素材料に含まれるホウ素－炭素結合を形成するホウ素の含有量（質量％）は、ＩＣＰ及びＸＰＳの測定結果から上述の方法にて算出した。 (The content of boron that forms a boron-carbon bond)
For the negative electrode active materials according to Examples 1 to 29 and Comparative Examples 1 to 5, the content (% by mass) of boron that forms a boron-carbon bond contained in the carbon material is measured by ICP and XPS. It was calculated from the results by the above method.
（ＸＲＤ測定）
　上記実施例１から実施例２７、実施例３４から実施例３７、比較例１から比較例５及び参考例１から参考例４に係る負極活物質について、上記測定方法にてＸＲＤ測定を行い、ＰＤＸＬを用いて（００２）面回折ピークの半値全幅及び（１０）面回折ピーク位置を得た。 (XRD measurement)
XRD measurements were performed on the negative electrode active materials according to Examples 1 to 27, Examples 34 to 37, Comparative Example 1 to Comparative Example 5, and Reference Example 1 to Reference Example 4 by the above measurement method, and PDXL was performed. Was used to obtain the full width at half maximum of the (002) plane diffraction peak and the position of the (10) plane diffraction peak.
（ラマンスペクトル測定）
　上記実施例１から実施例２７、実施例３４から実施例３７、比較例１及び比較例２並びに参考例１及び参考例２に係る負極活物質について、上記測定方法にてラマンスペクトルを測定した。炭素材料のラマン分光法によるスペクトルにおける１５００ｃｍ－１以上１７００ｃｍ－１以下の範囲での最大強度ＩＧに対する、１４００ｃｍ－１以上１５５０ｃｍ－１以下の範囲での最小強度ＩＶの比ＩＶ／ＩＧを、ラマンスペクトルの測定結果から上述の方法にて算出した。 (Raman spectrum measurement)
The Raman spectra of the negative electrode active materials according to Examples 1 to 27, Examples 34 to 37, Comparative Example 1 and Comparative Example 2, and Reference Example 1 and Reference Example 2 were measured by the above measuring method. The ratio of the minimum intensity IV in the range of 1400 cm -1 to 1550 cm -1 to the maximum intensity IG in the range of 1500 cm -1 or more and 1700 cm -1 or less in the spectrum of carbon material by Raman spectroscopy IV / IG . Was calculated by the above method from the measurement results of the Raman spectrum.
（ｄＱ／ｄＶ比の算出）
　実施例１から実施例２７、実施例３４から実施例３７、比較例１から比較例５及び参考例１から参考例４の非水電解質蓄電素子について、上記初期充放電の２サイクル目の定電流放電時の挙動に基づいて、上記の方法でｄＱ／ｄＶ曲線を得た。ｄＱ／ｄＶ曲線において、電圧範囲１．０Ｖ以上１．４Ｖ以下におけるｄＱ／ｄＶの最小値に対する、電圧範囲１．４Ｖ以上２．０Ｖ以下におけるｄＱ／ｄＶの最大値の比（ｄＱ／ｄＶ比）の算出を行った。 (Calculation of dQ / dV ratio)
For the non-aqueous electrolyte power storage elements of Examples 1 to 27, Examples 34 to 37, Comparative Example 1 to Comparative Example 5, and Reference Example 1 to Reference Example 4, the constant current in the second cycle of the initial charge / discharge. Based on the behavior at the time of discharge, a dQ / dV curve was obtained by the above method. In the dQ / dV curve, the ratio of the maximum value of dQ / dV in the voltage range of 1.4V or more and 2.0V or less (dQ / dV ratio) to the minimum value of dQ / dV in the voltage range of 1.0V or more and 1.4V or less. Was calculated.
　実施例１から実施例２７、実施例３４から実施例３７、比較例１から比較例５及び参考例１から参考例５の評価結果を表２に示す。 Table 2 shows the evaluation results of Example 1 to Example 27, Example 34 to Example 37, Comparative Example 1 to Comparative Example 5, and Reference Example 1 to Reference Example 5.
（酸素脱離量の測定）
　実施例１から実施例６、実施例１１、実施例１２、実施例２１及び比較例２に係る負極活物質について、８００℃超の雰囲気温度下における酸素の脱離量を上述の方法にて測定した。 (Measurement of oxygen desorption amount)
For the negative electrode active materials according to Examples 1 to 6, Example 11, Example 12, Example 21 and Comparative Example 2, the amount of oxygen desorbed at an atmospheric temperature of more than 800 ° C. was measured by the above method. did.
（充放電ヒステリシスの算出）
　実施例１から実施例６、実施例１１、実施例１２、実施例２１及び比較例２の非水電解質蓄電素子に対して、上記初期充放電の２サイクル目の充電時の平均閉回路電位と放電時の平均閉回路電位との差を算出し、充放電ヒステリシスとした。実施例１から実施例６、実施例１１、実施例１２、実施例２１及び比較例２の評価結果を表３に示す。 (Calculation of charge / discharge hysteresis)
With respect to the non-aqueous electrolyte power storage elements of Examples 1 to 6, Example 11, Example 12, Example 21, and Comparative Example 2, the average closed circuit potential at the time of charging in the second cycle of the initial charge / discharge. The difference from the average closed circuit potential at the time of discharge was calculated and used as the charge / discharge hysteresis. Table 3 shows the evaluation results of Examples 1 to 6, Example 11, Example 12, Example 21, and Comparative Example 2.
（過充電時のクーロン効率）
　実施例２８及び実施例２９の非水電解質蓄電素子に対して、上記と同様に２サイクルの初期充放電を実施した。２サイクル目の放電容量に１時間で到達する電流を１Ｃとした。次いで、過充電試験を次に示す手順で実施した。充電時間を１．５時間とし、充電電流１ＣでＣＣ充電を行った。過充電後に１０分の休止時間を設け、放電電流１Ｃで放電終止電圧２．０ＶのＣＣ放電を行った。さらに１０分の休止後に、放電電流０．１Ｃで放電終止電圧２．０ＶのＣＣ放電を行った。この時の充電電気量に対する、放電容量の和の百分率を過充電時のクーロン効率とし、表４に示す。 (Coulomb efficiency during overcharging)
The non-aqueous electrolyte power storage elements of Examples 28 and 29 were subjected to two cycles of initial charge / discharge in the same manner as described above. The current that reaches the discharge capacity of the second cycle in 1 hour was set to 1C. Then, the overcharge test was carried out according to the procedure shown below. The charging time was 1.5 hours, and CC charging was performed with a charging current of 1 C. After an overcharge, a rest period of 10 minutes was provided, and CC discharge with a discharge end voltage of 2.0 V was performed with a discharge current of 1 C. After a further 10-minute pause, CC discharge with a discharge end voltage of 2.0 V was performed with a discharge current of 0.1 C. Table 4 shows the Coulomb efficiency at the time of overcharging as the percentage of the sum of the discharge capacities with respect to the amount of electricity charged at this time.
（粒子径分布の測定）
　実施例２、実施例３０から実施例３３に係る負極活物質について、測定装置に日機装社製Ｍｉｃｒｏｔｒａｃ（型番：ＭＴ３０００）を使用し、測定制御ソフトにＭｉｃｒｏｔｒａｃ  ＤＨＳ  ｆｏｒ  Ｗｉｎ９８（ＭＴ３０００）を使用して、レーザ回折・散乱法により粒子径分布を測定し、平均粒径を求めた結果を表５に示す。 (Measurement of particle size distribution)
For the negative electrode active materials according to Examples 2 and 30 to 33, a Microtrac (model number: MT3000) manufactured by Nikkiso Co., Ltd. was used as a measuring device, and a Microtrac DHS for Win98 (MT3000) was used as a measurement control software. Table 5 shows the results of measuring the particle size distribution by the laser diffraction / scattering method and determining the average particle size.
（ＸＲＤ測定）
　実施例１から実施例２７、実施例３４から実施例３７に係る負極活物質について、上記測定方法にてＸＲＤ測定を行い、マニュアル手法を用いて（００２）面回折ピークの半値全幅を得た結果を表６に示す。　 (XRD measurement)
The negative electrode active materials according to Examples 1 to 27 and Examples 34 to 37 were subjected to XRD measurement by the above measurement method, and the full width at half maximum of the (002) surface diffraction peak was obtained by using a manual method. Is shown in Table 6.
（放電電位）
　実施例１から実施例２７、実施例３４から実施例３７の非水電解質蓄電素子に対して、上記初期充放電の２サイクル目の放電時の平均閉回路電位を「放電電位」とした。結果を表６に示す。 (Discharge potential)
For the non-aqueous electrolyte power storage elements of Examples 1 to 27 and Examples 34 to 37, the average closed circuit potential during the second cycle of the initial charge / discharge was defined as the “discharge potential”. The results are shown in Table 6.
（高率充電電気量比）
　実施例３８から実施例４２及び比較例１の非水電解質蓄電素子に対して、上記と同様に２サイクルの初期充放電を実施した。２サイクル目の放電容量に１時間で到達する電流を１Ｃとした。次いで、高率充電電気量比の測定を次に示す手順で実施した。充電電流２Ｃで、充電終止電圧０．４Ｖの定電流定電圧（ＣＣＣＶ）充電を行った。充電終止条件は、定電圧充電が開始してから１２時間経過した時点とした（以下、このときの充電電気量を「２Ｃ充電電気量」ともいう）。充電後に１０分の休止時間を設け、放電電流１Ｃで放電終止電圧２．０ＶのＣＣ放電を行った。放電後に１０分の休止時間を設け、充電電流０．１Ｃで、充電終止電圧０．４Ｖの定電流定電圧（ＣＣＣＶ）充電を行った。充電終止条件は、定電圧充電が開始してから１２時間経過した時点とした。このときの充電電気量に対する、２Ｃ充電電気量の百分率を高率充電電気量比とした。結果を表７に示す。 (High rate charge electricity amount ratio)
The non-aqueous electrolyte power storage elements of Examples 38 to 42 and Comparative Example 1 were subjected to two cycles of initial charge / discharge in the same manner as described above. The current that reaches the discharge capacity of the second cycle in 1 hour was set to 1C. Then, the measurement of the high rate charge electricity amount ratio was carried out by the procedure shown below. With a charging current of 2C, constant current constant voltage (CCCV) charging with a charge termination voltage of 0.4 V was performed. The charging termination condition was set to the time when 12 hours had passed from the start of constant voltage charging (hereinafter, the amount of charging electricity at this time is also referred to as "2C charging electricity amount"). A 10-minute pause was provided after charging, and CC discharge with a discharge end voltage of 2.0 V was performed with a discharge current of 1 C. A constant current constant voltage (CCCV) charge with a charge termination voltage of 0.4 V was performed with a charge current of 0.1 C with a pause time of 10 minutes after the discharge. The charging termination condition was 12 hours after the start of constant voltage charging. The percentage of the 2C charging electricity amount with respect to the charging electricity amount at this time was defined as the high rate charging electricity amount ratio. The results are shown in Table 7.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000007
　表２に示されるように、負極基材にアルミニウム箔を使用可能な０．４Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）充電時において、炭素材料に含まれるホウ素－炭素結合を形成するホウ素の含有量が０．６質量％以上であり、ＩＶ／ＩＧが０．５以上である実施例１から２７の負極活物質は、比較例１から比較例５よりも放電容量及びクーロン効率が優れていた。また、当該負極活物質は、参考例１から参考例５の黒鉛、難黒鉛化性炭素、酸化黒鉛、ピッチ系炭素及び炭化ホウ素よりも放電容量及びクーロン効率が優れていた。 As shown in Table 2, when an aluminum foil can be used as the negative electrode base material and charged at 0.4 V (vs. Li / Li + ), the content of boron that forms a boron-carbon bond contained in the carbon material is high. The negative electrode active materials of Examples 1 to 27 having an IV / IG of 0.5 or more and 0.6% by mass or more were superior in discharge capacity and Coulomb efficiency to Comparative Examples 1 to 5. .. Further, the negative electrode active material was superior in discharge capacity and Coulomb efficiency to graphite, non-graphitizable carbon, graphite oxide, pitch-based carbon and boron carbide of Reference Examples 1 to 5.
　表３に示されるように、８００℃超の雰囲気温度下における酸素の脱離量が、炭素材料に対して２．４５質量％以下である場合、充放電ヒステリシスは０．０８７Ｖ以下と小さくなった。また、８００℃超で脱離する酸素の含有量が少ないほど、充放電ヒステリシスは小さくなる傾向があることがわかる。 As shown in Table 3, when the amount of oxygen desorbed at an atmospheric temperature of more than 800 ° C. was 2.45% by mass or less with respect to the carbon material, the charge / discharge hysteresis became as small as 0.087 V or less. .. It can also be seen that the smaller the content of oxygen desorbed above 800 ° C., the smaller the charge / discharge hysteresis tends to be.
　また、表４に示されるように、負極に導電剤としてカーボンナノチューブを含有する実施例２８の非水電解質蓄電素子は、実施例２９と比較して過充電時におけるクーロン効率が高かった。 Further, as shown in Table 4, the non-aqueous electrolyte power storage element of Example 28 containing carbon nanotubes as a conductive agent in the negative electrode had higher Coulomb efficiency at the time of overcharging as compared with Example 29.
　表５に示されるように、負極活物質の平均粒径が３．５６μｍ超７．６８μｍ未満のとき、放電容量が特に向上した。 As shown in Table 5, when the average particle size of the negative electrode active material was more than 3.56 μm and less than 7.68 μm, the discharge capacity was particularly improved.
　表６に示されるように、ＣｕＫαを線源とする粉末エックス線回折パターンにおける、マニュアル手法による（００２）面回折ピークの半値全幅が１．７７°超のとき、比較的卑な放電電位を示した。 As shown in Table 6, in the powder X-ray diffraction pattern using CuKα as a radiation source, when the full width at half maximum of the (002) plane diffraction peak by the manual method exceeds 1.77 °, a relatively low discharge potential is shown. ..
　表７に示されるように、非水溶媒としてＰＣを含有する非水電解液を用いたとき、高率充電電気量比が比較的高かった。また、非水溶媒としてＤＥＣを含有する非水電解液を用いたとき、高率充電電気量比が特に高かった。 As shown in Table 7, when a non-aqueous electrolyte solution containing PC was used as the non-aqueous solvent, the high rate charge electricity amount ratio was relatively high. Further, when a non-aqueous electrolyte solution containing DEC was used as the non-aqueous solvent, the high rate charge electricity amount ratio was particularly high.
　以上のことから、当該非水電解質蓄電素子用負極活物質は、０．３５Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）程度以上の比較的貴な電位領域において良好な充放電性能が得られることが示された。 From the above, it is shown that the negative electrode active material for the non-aqueous electrolyte power storage element can obtain good charge / discharge performance in a relatively noble potential region of about 0.35 V (vs. Li / Li + ) or more. rice field.
　本発明は、パーソナルコンピュータ、通信端末等の電子機器、自動車などの電源として使用される非水電解質蓄電素子、及びこれに備わる負極、負極活物質などに適用できる。 The present invention can be applied to electronic devices such as personal computers and communication terminals, non-aqueous electrolyte power storage elements used as power sources for automobiles, and negative electrodes and negative electrode active materials provided therein.
１　　非水電解質蓄電素子
２　　電極体
３　　容器
４　　正極端子
４１　正極リード
５　　負極端子
５１　負極リード
２０　蓄電ユニット
３０　蓄電装置 1 Non-aqueous electrolyte power storage element 2 Electrode body 3 Container 4 Positive terminal 41 Positive lead 5 Negative terminal 51 Negative lead 20 Power storage unit 30 Power storage device

Claims (12)

  1. 　ホウ素を含み、層状の結晶構造を有する炭素材料を含有し、
    　下記式１で求められる上記炭素材料に含まれるホウ素－炭素結合を形成するホウ素の含有量が０．６質量％以上であり、
    　上記炭素材料のラマン分光法によるスペクトルにおける１５００ｃｍ－１以上１７００ｃｍ－１以下の範囲での最大強度ＩＧに対する、１４００ｃｍ－１以上１５５０ｃｍ－１以下の範囲での最小強度ＩＶの比ＩＶ／ＩＧが０．５以上である非水電解質蓄電素子用負極活物質。
    　Ｘ＝Ａ×Ｄ／Ｅ　・・・１
    　式１中、Ｘは、ホウ素－炭素結合を形成するホウ素の含有量（質量％）、Ａは、高周波誘導結合プラズマ発光分光分析法により求められる上記炭素材料に含有される全ホウ素の含有量（質量％）、Ｄは、エックス線光電子分光法によるスペクトルにおいて、２７２ｅＶ以上３００ｅＶ以下の範囲で最大強度を示すＣ１ｓのピーク位置を２８４．８ｅＶとしたときの、１８６ｅＶ以上１８８ｅＶ以下の範囲のＢ１ｓの積分強度、Ｅは、上記エックス線光電子分光法によるスペクトルにおける、１８６ｅＶ以上１９６ｅＶ以下の範囲のＢ１ｓの積分強度である。     Contains boron and a carbon material with a layered crystal structure,
    The content of boron forming a boron-carbon bond contained in the carbon material obtained by the following formula 1 is 0.6% by mass or more.
    The ratio of the minimum intensity IV in the range of 1400 cm -1 or more and 1550 cm -1 or less to the maximum intensity IG in the range of 1500 cm -1 or more and 1700 cm -1 or less in the spectrum of the carbon material by Raman spectroscopy IV / I. A negative electrode active material for a non-aqueous electrolyte power storage element having a G of 0.5 or more.
    X = A × D / E ・ ・ ・ 1
    In formula 1, X is the content (% by mass) of boron forming a boron-carbon bond, and A is the content of total boron contained in the carbon material obtained by high frequency induced bond plasma emission spectroscopy (%). Mass%), D is the integrated intensity of B1s in the range of 186 eV or more and 188 eV or less when the peak position of C1s showing the maximum intensity in the range of 272 eV or more and 300 eV or less is 284.8 eV in the spectrum by X-ray photoelectron spectroscopy. , E are the integrated intensities of B1s in the range of 186 eV or more and 196 eV or less in the spectrum obtained by the X-ray photoelectron spectroscopy.
  2. 　８００℃超の雰囲気温度下における酸素の脱離量が、上記炭素材料に対して２．４５質量％以下である請求項１に記載の非水電解質蓄電素子用負極活物質。 The negative electrode active material for a non-aqueous electrolyte power storage element according to claim 1, wherein the amount of oxygen desorbed at an atmospheric temperature exceeding 800 ° C. is 2.45% by mass or less with respect to the carbon material.
  3. 　上記炭素材料の粒子径分布における平均粒径が、３．５６μｍ超７．６８μｍ未満である請求項１又は請求項２に記載の非水電解質蓄電素子用負極活物質。 The negative electrode active material for a non-aqueous electrolyte power storage element according to claim 1 or 2, wherein the average particle size in the particle size distribution of the carbon material is more than 3.56 μm and less than 7.68 μm.
  4. 　ＣｕＫαを線源とする粉末エックス線回折パターンにおける、マニュアル手法による（００２）面回折ピークの半値全幅が、１．７７°超である請求項１から請求項３の何れか１項に記載の非水電解質蓄電素子用負極活物質。 The non-water according to any one of claims 1 to 3, wherein the half-value total width of the (002) plane diffraction peak by the manual method in the powder X-ray diffraction pattern using CuKα as a radiation source is more than 1.77 °. Negative electrode active material for electrolyte storage elements.
  5. 　請求項１から請求項４の何れか１項に記載の非水電解質蓄電素子用負極活物質を含有する非水電解質蓄電素子用負極。 A negative electrode for a non-aqueous electrolyte power storage element containing the negative electrode active material for the non-aqueous electrolyte power storage element according to any one of claims 1 to 4.
  6. 　カーボンナノチューブをさらに含有する請求項５に記載の非水電解質蓄電素子用負極。 The negative electrode for a non-aqueous electrolyte power storage element according to claim 5, further containing carbon nanotubes.
  7. 　純アルミニウム又はアルミニウム合金からなる負極基材をさらに有する請求項５又は請求項６に記載の非水電解質蓄電素子用負極。 The negative electrode for a non-aqueous electrolyte power storage element according to claim 5 or 6, further comprising a negative electrode base material made of pure aluminum or an aluminum alloy.
  8. 　請求項５、請求項６又は請求項７に記載の非水電解質蓄電素子用負極を備える非水電解質蓄電素子。 A non-aqueous electrolyte power storage element comprising the negative electrode for the non-water electrolyte power storage element according to claim 5, claim 6 or claim 7.
  9. 　非水溶媒としてプロピレンカーボネートを含有する非水電解液を備える請求項８に記載の非水電解質蓄電素子。 The non-aqueous electrolyte storage element according to claim 8, which comprises a non-aqueous electrolyte solution containing propylene carbonate as a non-aqueous solvent.
  10. 　非水溶媒としてジエチルカーボネートを含有する非水電解液を備える請求項８又は請求項９に記載の非水電解質蓄電素子。 The non-aqueous electrolyte power storage element according to claim 8 or 9, further comprising a non-aqueous electrolyte solution containing diethyl carbonate as a non-aqueous solvent.
  11. 　通常使用時の充電終止電圧における負極電位が、０．３５Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）以上である請求項８から請求項１０の何れか１項に記載の非水電解質蓄電素子。 The non-aqueous electrolyte power storage element according to any one of claims 8 to 10, wherein the negative electrode potential at the end-of-charge voltage during normal use is 0.35 V (vs. Li / Li + ) or more.
  12. 　非水電解質蓄電素子を二以上備え、且つ請求項８から請求項１１のいずれか１項に記載の非水電解質蓄電素子を一以上備えた蓄電装置。 A power storage device including two or more non-aqueous electrolyte power storage elements and one or more non-water electrolyte power storage elements according to any one of claims 8 to 11.
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