JP6498423B2 - Method for manufacturing power storage device - Google Patents

Description

The present invention relates to a power storage device and a method for manufacturing a power storage device.

Energy storage systems such as load leveling devices such as photovoltaic power generation and wind power generation, instantaneous voltage drop countermeasure devices for electronic devices such as computers, and energy regeneration devices for electric vehicles and hybrid cars have a large energy capacity. There is a need for an electricity storage device that can be rapidly charged and discharged. Lithium ion secondary batteries and lithium ion capacitors have been proposed as power storage devices capable of such rapid charging / discharging and long life.

Lithium ion secondary batteries use lithium metal oxides such as lithium cobaltate for the positive electrode, and can store charges using lithium ions as lithium ion metal oxides. In the negative electrode, lithium ions can be stored between carbon material layers. Furthermore, since a non-aqueous electrolyte can be used and the potential difference between the electrodes can be increased, a large amount of energy can be stored.

The lithium ion capacitor uses a porous carbon material on the positive electrode side, and stores electric charge by adsorption / desorption of anions or lithium ions. Since the electric double layer of the positive electrode is a thin layer of about one molecular layer formed on the surface of the porous carbon material, a large amount of electric charge can be stored and a large capacity can be obtained. In the negative electrode, lithium ions can be stored between layers of carbon materials.

Both the lithium ion secondary battery and the lithium ion capacitor are charged and discharged by the transfer of lithium ions between the positive electrode and the negative electrode. In a lithium ion capacitor, since lithium (lithium ions or metallic lithium) involved in charging / discharging is not stored in either the positive electrode or the negative electrode in the battery manufacturing stage, it is necessary to store lithium in advance.
As a means for storing lithium ions involved in charge / discharge, a method of pre-doping the negative electrode is known. This is a method in which lithium involved in charge / discharge is doped in advance on a negative electrode made of a carbon material or the like before the first charge.

These are power storage devices mainly utilizing the redox reaction of lithium on the negative electrode side.
On the other hand, regarding the positive electrode, an electricity storage device using an oxidation-reduction reaction has been proposed. Specifically, a method is disclosed in which anion insertion / extraction sites are increased by inserting and desorbing anions in the electrolyte into and out of a carbonaceous material having a positive electrode layer structure.

As a manufacturing method of such an electricity storage device that combines a positive electrode with increased anion insertion / extraction sites and a negative electrode pre-doped with lithium ions, Patent Document 1 discloses that an electrode is manufactured to manufacture a positive electrode and a negative electrode. A method for charging and discharging by individually assembling cells for a battery is disclosed, and Patent Document 2 discloses a method for producing a cell for an electricity storage device composed of an electrode serving as a lithium supply source in addition to a positive electrode and a negative electrode. A method for treating the positive electrode and the negative electrode (charging / discharging) is disclosed.

JP 2010-254537 A Japanese Patent No. 5429678

However, in the method described in Patent Document 1, it is necessary to separately produce a cell for treating the positive electrode and a cell for treating the negative electrode, and combine the taken-out positive electrode and negative electrode again, so that the manufacturing process is complicated. Therefore, there was a problem that cost reduction was difficult.

In the method described in Patent Document 2, since the positive electrode and the negative electrode are processed after the storage device is assembled, the manufacturing process is simplified. However, it is necessary to use current collectors having through holes (pores) for the positive electrode current collector and the negative electrode current collector, and there is a problem that the cost required for processing the current collector having the pores is high.
Furthermore, in the method described in Patent Document 2, since lithium is scattered as a lithium supply source inside the cell, there is a possibility that lithium may be scattered and short-circuited. Difficulty was a problem.
Further, when the electricity storage device is repeatedly used, there is a problem that the deterioration of the negative electrode is accelerated.

As a result of intensive studies by the inventor in view of the above-described problems, first, the charging operation is performed on the positive electrode and the negative electrode, and then the negative electrode is recovered and replaced with a lithium-containing electrode, and then the discharging operation is performed. , The time required for pre-doping of lithium ions can be greatly shortened, and a uniform pre-doping of lithium ions for the negative electrode can be performed, and at the same time, the treatment for increasing the charge / discharge capacity for the positive electrode active material As a result, it has been found that the deterioration of the negative electrode can be suppressed, and the present invention has been achieved.

That is, the method for manufacturing an electricity storage device of the present invention includes electrically connecting a positive electrode on which a positive electrode active material that is a carbonaceous material is formed and a negative electrode on which a negative electrode active material that is a carbonaceous material is formed. And an anion that constitutes the lithium salt is inserted into the positive electrode active material to produce an anion-inserted positive electrode, and lithium to the negative electrode active material is charged. A charging step for pre-doping ions to produce a pre-doped negative electrode, a negative electrode exchanging step for recovering the pre-doped negative electrode and replacing it with a lithium-containing electrode, and electrically connecting the anion-inserted positive electrode and the lithium-containing electrode. A discharge step of desorbing the anion from the inside of the positive electrode active material by discharging in the non-aqueous electrolyte, and the positive electrode and the pred Characterized in that comprising the cell manufacturing process to produce a cell by combining the flop negative electrode.

In the method for manufacturing an electricity storage device of the present invention, first, a charging step is performed in which a positive electrode and a negative electrode are electrically connected and charged in a non-aqueous electrolyte. Through the charging step, an anion constituting a lithium salt is inserted into the positive electrode active material, and lithium ions are inserted into the negative electrode active material. By inserting an anion into the positive electrode active material, the positive electrode becomes an anion-inserted positive electrode, and by performing lithium ion pre-doping on the negative electrode active material, the negative electrode becomes a pre-doped negative electrode.
At this time, since lithium ions are taken into the negative electrode active material and anions are taken into the positive electrode active material, the lithium salt concentration in the non-aqueous electrolyte is lowered.

Then, the negative electrode exchange process which collect | recovers a pre dope negative electrode and replaces with a lithium containing electrode is performed. The collected pre-doped negative electrode is used in a cell manufacturing process described later.

Then, the discharge process which electrically connects an anion insertion positive electrode and a lithium containing electrode and discharges is performed.
The anion inserted inside the positive electrode active material is desorbed by the discharge, but the interlayer distance of the positive electrode active material increased by the insertion of the anion is completely the same even after the anion is desorbed. The positive electrode active material from which the anion has been desorbed becomes a positive electrode active material that has been scattered, and the anion is easily inserted and desorbed at the portion where the interlayer distance has increased. Become. Therefore, the charge / discharge capacity of the electricity storage device can be improved.
In addition, since lithium ions are released from the lithium-containing electrode by discharge and anions are released from the positive electrode active material in which the anions are inserted, the lithium salt concentration consumed and decreased by the charging step increases, and the nonaqueous electrolyte solution Is played.

A cell is produced by performing the cell production process which combines the positive electrode which passed through the said discharge process, and the said pre dope negative electrode.
At this time, the regenerated nonaqueous electrolyte may be used as the nonaqueous electrolyte constituting the cell, or a separately prepared nonaqueous electrolyte may be used.
When using the regenerated non-aqueous electrolyte, for example, after the discharging step, the lithium-containing electrode can be taken out and replaced with the recovered pre-doped negative electrode to produce a cell.

When using a separately prepared non-aqueous electrolyte, the positive electrode that has undergone the discharge process is collected after the above-described discharge process, combined with the pre-doped negative electrode that has been collected in advance, and the cell is prepared by adding a separately prepared non-aqueous electrolyte. Can be produced.
The produced cell becomes an electricity storage device by connecting one or more cells in an arbitrary combination.

In the method for manufacturing an electricity storage device of the present invention, since the positive electrode and the negative electrode can be processed in parallel, the manufacturing process can be simplified.
Further, in the charging process, since the amount of current and the electrode position can be monitored and adjusted, the uniformity of lithium ion pre-doping in the negative electrode can be achieved. In addition, since lithium metal is not used for the treatment of the positive electrode, generation of lithium dendrite can be suppressed, and it can be said that safety is high.
Therefore, the method for manufacturing an electricity storage device of the present invention makes it possible to manufacture an electricity storage device with high safety and high capacity at a low cost and in a short time.

In the method for producing an electricity storage device of the present invention, in the charging step and the discharging step, nanobubbles that are fine pores that enable insertion and desorption of anions constituting a lithium salt are formed inside the positive electrode active material. It is preferable to prepare a nanobubble positive electrode.
When nanobubbles are formed in the positive electrode active material in the charging step and the discharging step, the number of sites where insertion and desorption of anions of the lithium salt can be increased, so that a high charge / discharge capacity can be obtained.
Note that when the positive electrode active material is enlarged and observed with a transmission electron microscope or the like, nanobubbles in which the carbon layer structure is distorted or the layer structure is blurred are observed. For the formation of nanobubbles, see Nissin Electric Technical Report VOL. 57, no. 2 2012.11 “Basic characteristics of dual carbon battery”.

In the method for producing an electricity storage device of the present invention, the lithium-containing electrode is preferably made of a carbonaceous material that has been pre-doped with lithium ions.
If the lithium-containing electrode is made of a carbonaceous material pre-doped with lithium ions, the lithium-containing electrode retains its shape even when lithium is eluted from the lithium-containing electrode. It is difficult to cause deformation and short circuit, and lithium fragments can be prevented from being scattered in the electrolyte and short circuiting.

In the method for producing an electricity storage device of the present invention, the positive electrode active material is formed on a foil that separates the non-aqueous electrolyte between the front and back sides, and the negative electrode active material separates the non-aqueous electrolyte between the front and back sides. It is preferable to be formed on the foil.
When the positive electrode active material and the negative electrode active material are respectively formed on the foil that separates the non-aqueous electrolyte between the front and back surfaces, it is not necessary to perform fine processing such as pore formation processing on the foil, and the manufacturing cost is suppressed. be able to. In addition, since it is not necessary to form pores, even when a thin foil is used, conductivity and strength can be ensured, and the size of the electricity storage device can be reduced.

In the electricity storage device of the present invention, a positive electrode active material that is a carbonaceous material is formed on a foil that separates a non-aqueous electrolyte between the front and back sides, and an insertion / desorption of an anion constituting a lithium salt is formed inside the positive electrode active material. A negative electrode active material that is a carbonaceous material is formed on a nanobubble positive electrode in which nanobubbles, which are fine pores that can be separated, are formed, and a foil that separates the non-aqueous electrolyte between the front and back surfaces, and the negative electrode active material And a pre-doped negative electrode subjected to lithium ion pre-doping.

The electricity storage device of the present invention includes a nanobubble positive electrode in which nanobubbles are formed inside a positive electrode active material, and a pre-doped negative electrode in which lithium ion pre-doping is performed on the negative electrode active material.
The positive electrode active material in which nanobubbles are formed has a higher charge / discharge capacity because there are more sites where anions constituting the lithium salt can be inserted and desorbed than in the positive electrode active material in which nanobubbles are not formed. Moreover, by using the negative electrode active material in which lithium ions are pre-doped, more lithium is always inserted into the negative electrode than the amount of anions inserted into the positive electrode. For this reason, even when the electricity storage device is completely discharged, lithium is inserted into the negative electrode, and the electric potential of the negative electrode can be stabilized. Therefore, even when charging / discharging is repeated, deterioration of the negative electrode associated with charging / discharging can be suppressed, and the number of times that the electricity storage device can be used can be increased. In addition, since the potential fluctuation of the negative electrode can be almost ignored, the charge / discharge reaction can be performed using most of the positive electrode capacity, so that the capacity utilization rate and the energy density can be improved.
In addition, the electricity storage device of the present invention uses a foil (also referred to as a plain foil) that separates a non-aqueous electrolyte between the front and back as a positive electrode current collector and a negative electrode current collector (hereinafter also simply referred to as a current collector). ing. Since this is a foil not subjected to pore formation processing or the like, the manufacturing cost can be reduced, and an inexpensive product can be provided.
In addition, when producing a positive electrode and a negative electrode using a foil that separates the non-aqueous electrolyte between the front and back surfaces, from the current collector to the active material, compared to the case of using a foil that has been subjected to pore formation processing, etc. Therefore, it is difficult for the anion and lithium ion insertion / extraction reaction to be uneven.
Furthermore, since it is not necessary to form pores in the current collector, even when a thin foil is used, conductivity and strength can be ensured, and the size of the electricity storage device can be reduced.

In the electricity storage device of the present invention, the nanobubble positive electrode is electrically connected to a positive electrode and a negative electrode on which a positive electrode active material that is a carbonaceous material is formed, and charged in a non-aqueous electrolyte containing a lithium salt and a non-aqueous solvent. By charging the anion constituting the lithium salt into the positive electrode active material to produce an anion-inserted positive electrode, electrically connecting the anion-inserted positive electrode and the lithium-containing electrode, It is preferably formed by a discharge step in which the anion is desorbed from the inside of the positive electrode active material by discharging in a non-aqueous electrolyte.

When the nanobubble cathode is formed inside the electricity storage device, the lithium supply source and the lithium supply source are fixed inside the electricity storage device in order to form nanobubbles without detaching the lithium ions pre-doped in the anode active material. It is necessary to arrange in advance in the electric storage device an electrode for energizing the support for conducting the current and the lithium supply source and the positive electrode (the support may also serve as the electrode).
On the other hand, when the positive electrode constituting the electricity storage device is a nanobubble positive electrode obtained by the charging step and the discharging step, since the nanobubbles are already formed in the positive electrode active material, the lithium supply source, the support and the electrode are There is no need to place it inside the electricity storage device. Therefore, the dead material can be reduced by increasing the active material weight inside the electricity storage device by the arrangement space of the lithium supply source, the support and the electrode, and the energy density of the electricity storage device can be improved. Also, if nanobubble formation inside the electricity storage device was insufficient, the lithium supply source may remain inside the electricity storage device, causing lithium dendrite to precipitate and float, causing a short circuit, In the electricity storage device having the above configuration, since the lithium supply source is not arranged inside the electricity storage device, a short circuit due to precipitation of lithium dendrite can be suppressed.

In the electricity storage device of the present invention, the pre-doped negative electrode is electrically connected to a negative electrode on which a negative electrode active material, which is a carbonaceous material, and a positive electrode are connected, and charged in a non-aqueous electrolyte containing a lithium salt and a non-aqueous solvent. By doing so, it is preferable that the negative electrode active material is formed by a charging step in which lithium ions are pre-doped.

When the pre-doped negative electrode is produced inside the electricity storage device, it is usually necessary to supply an amount of lithium necessary for pre-doping the negative electrode from the lithium supply source. For this reason, a lithium supply source, a support for fixing the lithium supply source inside the electricity storage device, and an electrode for energizing the lithium supply source and the negative electrode (the support may also serve as an electrode) are stored in advance. Must be placed inside.
On the other hand, when the negative electrode constituting the power storage device is a pre-doped negative electrode prepared by the charging step, it is not necessary to arrange the lithium supply source, support and electrode inside the power storage device. Therefore, the weight of the active material inside the electricity storage device can be increased by the arrangement space of the lithium supply source, the support, and the electrode, so that dead space can be reduced and the energy density of the electricity storage device can be improved.
In addition, when the lithium ion pre-doping is insufficient, high-activity metallic lithium remains in the electricity storage device, which may cause a short circuit, which is preferable from the viewpoint of safety. Absent.

Fig.1 (a) is a conceptual diagram which shows typically the state of the positive electrode and negative electrode immediately after the start of the charge process in the manufacturing method of the electrical storage device of this invention, FIG.1 (b) is manufacture of the electrical storage device of this invention. It is a conceptual diagram which shows typically the state of the positive electrode and negative electrode immediately after completion | finish of the charge process in a method. FIG. 2 is a conceptual diagram schematically showing a negative electrode replacement step in the method for manufacturing an electricity storage device of the present invention. FIG. 3A is a conceptual diagram schematically showing the state of the anion-inserted positive electrode and the lithium-containing electrode immediately after the start of the discharge process in the method for producing an electricity storage device of the present invention, and FIG. It is a conceptual diagram which shows typically the state of the positive electrode and lithium containing electrode which passed through the discharge process in the manufacturing method of an electrical storage device. FIG. 4 is a cross-sectional view schematically showing an example of an electricity storage device manufactured by the method for manufacturing an electricity storage device of the present invention. FIG. 5 is a cross-sectional view schematically showing another example of the electricity storage device of the present invention. FIG. 6 is a cross-sectional view schematically showing still another example of the electricity storage device of the present invention. FIG. 7 is a graph showing changes in the potential between [positive electrode and negative electrode] and the potential between [positive electrode and lithium-containing electrode] during the charging process to the discharging process according to Example 1.

(Detailed description of the invention)
Hereinafter, the method for manufacturing an electricity storage device and the electricity storage device of the present invention will be specifically described. However, the present invention is not limited to the following configurations, and can be applied with appropriate modifications without departing from the scope of the present invention. Note that the present invention also includes a combination of two or more desirable configurations of the present invention described below.

The manufacturing method of the electrical storage device of this invention consists of a charge process, a negative electrode exchange process, a discharge process, and a cell preparation process.

First, the charging process will be described.
In the charging step, the positive electrode and the negative electrode are electrically connected, and charging is performed to produce the anion-inserted positive electrode and the pre-doped negative electrode.

First, the positive electrode will be described.
The positive electrode used in the charging step is formed by forming a positive electrode active material on a positive electrode current collector.

The material constituting the positive electrode current collector is preferably a material having excellent corrosion resistance inside the electricity storage device, and examples thereof include stainless steel, titanium, aluminum, and the like, from the viewpoint of manufacturing cost and corrosion resistance, aluminum. Is preferred.

The positive electrode current collector is preferably a foil that separates the non-aqueous electrolyte between the front and back sides.
When the positive electrode current collector is a foil that separates the non-aqueous electrolyte between the front and back surfaces, it can be manufactured at a lower cost than a foil that has been subjected to pore formation processing or the like, and thus the manufacturing cost is excellent. In addition, since it is not necessary to form pores by using a foil that separates the non-aqueous electrolyte solution between the front and back surfaces, the conductivity and strength can be ensured even if a thin foil is used. Can be reduced.

The thickness of the positive electrode current collector is preferably 10 to 100 μm, more preferably 10 to 60 μm, and still more preferably 10 to 40 μm.

The positive electrode active material may be a carbonaceous material having a layer structure, such as graphite, non-graphitizable carbon, natural graphite, artificial graphite, non-graphitizable carbon, graphitizable carbon, low-temperature calcined carbon and activated carbon. Preferably, graphite, non-graphitizable carbon and artificial graphite are more preferable.

As a method of forming the positive electrode active material on the positive electrode current collector, for example, the positive electrode active material is dispersed in a solvent to form a positive electrode active material slurry, and this positive electrode active material slurry is used as a doctor blade method applicator or a baker type application. For example, a method of applying on a positive electrode current collector using a coating machine such as a coater and drying.
You may add a conductive support agent, a binder, etc. to a positive electrode active material slurry as needed.

What is necessary is just to set the thickness of the positive electrode active material layer after drying suitably according to charging / discharging capacity | capacitance and the internal capacity | capacitance of an electrical storage device, for example, 10-100 micrometers is preferable and 20-60 micrometers is more preferable.
When the thickness of the positive electrode active material layer after drying is less than 10 μm, the weight ratio indicated by the current collector increases, and the charge / discharge capacity of the electricity storage device per unit weight may be too small. On the other hand, when the thickness of the positive electrode active material layer after drying exceeds 100 μm, the positive electrode active material may be peeled off from the positive electrode current collector along with charge / discharge of the electricity storage device.

The binder is preferably a water-soluble styrene butadiene rubber (SBR), for example, a mixture of carboxymethyl cellulose and styrene butadiene rubber (SBR), polyvinylidene fluoride, polyamideimide, polyimide, polytetrafluoroethylene, etc., and polyvinylidene fluoride. Is more preferable.
In addition, it is preferable that the quantity of the binder contained in a positive electrode active material slurry is 1 to 20 weight% in conversion of solid content.

Examples of the conductive aid include ketjen black, acetylene black, furnace black, carbon nanotube, and carbon nanofiber. In addition, it is preferable that the quantity of the conductive support agent contained in a positive electrode active material is 1 to 50 weight%.

Examples of the solvent include water, N, N-dimethylformamide, N-methyl-2-pyrrolidone (NMP) and the like.
As a combination of the solvent and the binder, for example, a water-soluble SBR rubber can be used as the binder, and water can be used as the solvent.

In the positive electrode preparation step, the positive electrode active material may be formed only on one surface of the positive electrode current collector, or the positive electrode active material may be formed on both surfaces of the positive electrode current collector. In the case of a stacked storage device in which a positive electrode and a negative electrode are continuously wound or alternately stacked, it is preferable that a positive electrode active material is formed on both surfaces of the positive electrode current collector.

Subsequently, the negative electrode will be described.
The negative electrode used in the charging step is formed by forming a negative electrode active material on a negative electrode current collector.

The material constituting the negative electrode current collector is preferably excellent in corrosion resistance inside the electricity storage device and does not form an alloy with lithium, for example, copper, nickel, etc., from the viewpoint of manufacturing cost, Copper is preferred.

The negative electrode current collector is preferably a foil that separates the non-aqueous electrolyte between the front and back sides.
When the negative electrode current collector is a foil that separates the non-aqueous electrolyte between the front and back surfaces, the negative electrode current collector can be manufactured at a lower cost than a foil that has been subjected to pore formation processing or the like.
In addition, since it is not necessary to form pores by using a foil that separates the non-aqueous electrolyte between the front and back surfaces, conductivity and strength can be ensured even with a thin foil, and the size of the electricity storage device can be reduced. Can be small.

The thickness of the negative electrode current collector is preferably 10 to 100 μm, more preferably 20 to 80 μm, and still more preferably 30 to 60 μm.

The negative electrode active material may be a carbonaceous material having a layer structure, and for example, the same material as the positive electrode active material is preferably used.

As a method for forming the negative electrode active material on the negative electrode current collector, a method similar to the method for forming the positive electrode active material described above on the positive electrode current collector can be suitably used.
The types and ratios of the solvent, conductive assistant, binder, etc. used are the same as in the case of the positive electrode active material.
Further, the negative electrode active material may be formed only on one surface of the negative electrode current collector, or the negative electrode active material may be formed on both surfaces of the negative electrode current collector. In the case of a stacked electricity storage device, it is preferable that a negative electrode active material is formed on both surfaces of a negative electrode current collector.

In the charging process, the anion constituting the lithium salt is inserted into the positive electrode active material by electrically connecting the positive electrode and the negative electrode and charging in a non-aqueous electrolyte containing a lithium salt and a non-aqueous solvent. Then, an anion-inserted positive electrode is prepared, and a pre-doped negative electrode is prepared by pre-doping lithium ions into the negative electrode active material.
In the charging step, charging is preferably performed until the potential of the anion-inserted positive electrode is 5 to 6 V (vs Li / Li ⁺ ), and the potential of the pre-doped negative electrode is 0.06 to 0.12 V (vs Li / Li ⁺ ) It is preferable to charge until it becomes.

The behavior of the positive electrode and the negative electrode in the charging process will be described with reference to FIGS. 1 (a) and 1 (b).
Fig.1 (a) is a conceptual diagram which shows typically the state of the positive electrode and negative electrode immediately after the start of the charge process in the manufacturing method of the electrical storage device of this invention, FIG.1 (b) is manufacture of the electrical storage device of this invention. It is a conceptual diagram which shows typically the state of the positive electrode and negative electrode immediately after completion | finish of the charge process in a method.
In the charging step, as shown in FIG. 1A, the positive electrode 10 and the negative electrode 30 are present facing each other in the non-aqueous electrolyte 60.
The positive electrode 10 includes a positive electrode current collector 12 and a positive electrode active material 11 formed on the surface thereof, and the negative electrode 30 includes a negative electrode current collector 32 and a negative electrode active material 31 formed on the surface thereof.
The positive electrode 10 and the negative electrode 30 are connected to the charge / discharge tester 100, and the positive electrode 10 and the negative electrode 30 are electrically connected by the charge / discharge tester 100 to be charged. When the battery is charged, among the components constituting the non-aqueous electrolyte, an anion of a lithium salt represented by LiX (represented by X ⁻ in FIG. 1A) is inserted into the positive electrode active material 11. Is done. At the same time, lithium ions (represented by Li ⁺ in FIG. 1A) are inserted into the negative electrode active material 31.
When the charging step is completed, as shown in FIG. 1B, the anion is inserted into the positive electrode active material 11, whereby the positive electrode active material 16 with the anion inserted is obtained, and the positive electrode 10 becomes the anion-inserted positive electrode 15. . At the same time, lithium ions are inserted into the negative electrode active material 31 to become a lithium pre-doped negative electrode active material 41, and the negative electrode 30 becomes a pre-doped negative electrode 40.
Here, the pretreatment for the pre-doped negative electrode 40 is completed.
In the charging step, a part of the lithium ions and anions constituting the non-aqueous electrolyte 60 is taken into the anion-inserted positive electrode and the pre-doped negative electrode, so that the lithium salt concentration of the non-aqueous electrolyte decreases.

In the charging step, one of the surfaces of the positive electrode current collector and the negative electrode current collector (the surface facing the counter electrode) preferentially causes the reaction. Therefore, when the positive electrode active material or the negative electrode active material is formed on both surfaces of the current collector, the current collector is rotated halfway during the charging process, and the above-mentioned surface is also reacted with respect to the non-reactive surface. A reaction may occur.

Non-aqueous solvents constituting the non-aqueous electrolyte used in the charging step include ethylene carbonate (EC), butylene carbonate (BC), vinylene carbonate (VC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl Carbonate (DEC), sulfolane, dimethoxyethane and the like are preferably used, and one or more may be used in combination.
In the charging step, it is important to form a solid electrolyte interface (SEI) film obtained by decomposing a part of the non-aqueous electrolyte component on the surface of the negative electrode active material. It is easily formed when an ethylene carbonate non-aqueous solvent such as ethylene carbonate (EC), butylene carbonate (BC), vinylene carbonate (VC) is used as the solvent.

The lithium salt constituting the non-aqueous electrolyte used in the charging step is not particularly limited as long as it is dissociated into a lithium ion and an anion in a non-aqueous solvent, but LiPF ₆ , LiClO ₄ , LiBF ₄ , LiAsF ₆ , Examples include LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , and LIC (CF ₃ SO ₂ ) _3. Among these, LiPF ₆ is preferable.

Although the charge rate in a charge process is not specifically limited, It is preferable that it is 0.1-10C, and it is more preferable that it is 0.2-5C.
When the charging rate is less than 0.1 C, the time required for the charging process becomes long, which is not preferable from the viewpoint of manufacturing efficiency. On the other hand, when the charge rate exceeds 10 C, the anion insertion reaction with respect to the positive electrode active material and the lithium ion pre-doping with respect to the negative electrode active material may not proceed sufficiently.

In addition, it can be determined by analyzing the positive electrode active material before and after the charging step that the anion has been inserted into the positive electrode active material in the charging step.
Specifically, when the positive electrode active material is magnified and observed with a transmission electron microscope, the carbon layer structure is distorted or the layer structure is blurred. The part where this layer structure is distorted or blurred is a nanobubble. For the formation of nanobubbles, see Nissin Electric Technical Report VOL. 57, no. 2 2012.11 “Basic characteristics of dual carbon battery”.

Subsequently, the negative electrode replacement step will be described.
In the negative electrode replacement step, the pre-doped negative electrode obtained in the charging step is collected and replaced with a lithium-containing electrode.
FIG. 2 is a conceptual diagram schematically showing a negative electrode replacement step in the method for manufacturing an electricity storage device of the present invention.
As shown in FIG. 2, the pre-doped negative electrode 40 obtained by the charging process is collected and replaced with a lithium-containing electrode 50.
Although the process for the pre-doped negative electrode is completed in the charging step, it is necessary to continue the process for the anion-inserted positive electrode. Therefore, an electrode for performing a subsequent discharge process is required for the anion-inserted positive electrode.
In the subsequent discharge step, it is preferable to regenerate the non-aqueous electrolyte, and therefore a lithium-containing electrode is used as the negative electrode having the ability to release lithium ions.

The lithium-containing electrode is composed of a lithium-containing compound formed on the negative electrode current collector. However, it may consist only of lithium-containing compounds.
The lithium-containing compound is not particularly limited as long as it can release lithium ions at the time of discharge. For example, metallic lithium, LiAl, LiZn, Li ₃ Bi, Li ₃ Cd, Li ₃ Sb, Li ₄ Si, Li _4. Examples thereof include a lithium alloy such as ₄ Pb and a carbonaceous material that is pre-doped with lithium ions.
From the viewpoint of suppressing a short circuit in the discharge process, a carbonaceous material pre-doped with lithium ions is preferable.
If the lithium-containing electrode is made of a carbonaceous material pre-doped with lithium ions, the shape of the lithium-containing electrode itself is retained even if lithium is eluted from the lithium-containing electrode. Therefore, it is possible to prevent a short circuit or a short circuit of lithium fragments scattered in the electrolyte.
In addition, it is also possible to use the pre dope negative electrode produced by the charge process mentioned above as a lithium containing electrode.

Next, the discharge process will be described.
In the discharging step, the anion-inserted positive electrode produced in the charging step and the lithium-containing electrode exchanged in the negative electrode exchanging step are electrically connected, and discharged in the non-aqueous electrolyte solution, so that the anion from the inside of the positive electrode active material. Is removed.
In the discharge step, it is preferable to perform discharge until the potential of the anion-inserted positive electrode becomes 3 V (vs Li / Li ⁺ ) in order to almost completely desorb the anion from the inside of the positive electrode active material.

The behavior of the anion-inserted positive electrode and the lithium-containing electrode in the discharge process will be described with reference to FIGS. 3 (a) and 3 (b).
FIG. 3A is a conceptual diagram schematically showing the state of the anion-inserted positive electrode and the lithium-containing electrode immediately after the start of the discharge process in the method for producing an electricity storage device of the present invention, and FIG. It is a conceptual diagram which shows typically the state of the positive electrode and lithium containing electrode which passed through the discharge process in the manufacturing method of an electrical storage device.
As shown in FIG. 3A, the anion-inserted positive electrode 15 and the lithium-containing electrode 50 are present facing each other in the non-aqueous electrolyte 60.
The anion-inserted positive electrode 15 includes a positive electrode current collector 12 and a positive electrode active material 16 having an anion formed on the surface thereof. The lithium-containing electrode 50 includes a negative electrode current collector 52 and a lithium-containing compound formed on the surface thereof. 51.
The anion-inserted positive electrode 15 and the lithium-containing electrode 50 are connected to the charge / discharge tester 100. By using the charge / discharge tester 100, the anion-inserted positive electrode 15 and the lithium-containing electrode 50 are electrically connected to discharge. It can be performed. When discharge is performed, the anion (indicated by X ⁻ in FIG. 3A) is desorbed from the inside of the positive electrode active material 16 in which the anion constituting the anion-inserted positive electrode 15 is inserted, and diffuses into the non-aqueous electrolyte 60. To do. At the same time, lithium ions (indicated by Li ⁺ in FIG. 3A) are desorbed from the lithium-containing compound 51 constituting the lithium-containing electrode 50 and diffused into the non-aqueous electrolyte 60.
When the anion is desorbed from the inside of the positive electrode active material 16 in which the anion is inserted, the interlayer distance of the positive electrode active material that has been increased by the insertion of the anion does not completely return even after the anion is desorbed. Therefore, the positive electrode active material 21 in which the anion easily inserts and desorbs, that is, the interlayer distance is increased. Therefore, when the discharge process is completed, as shown in FIG. 3B, the anion-inserted positive electrode 15 becomes the positive electrode 20 that has undergone the discharge process. And since the lithium salt density | concentration of the non-aqueous electrolyte which was falling by the discharge process mentioned above increases, a non-aqueous electrolyte will be reproduced | regenerated.

By performing the above-described charging step and the above-described discharging step, insertion / extraction of anions with respect to the positive electrode active material is facilitated, so that the charge / discharge capacity of the electricity storage device can be improved.
Note that a positive electrode active material having an increased interlayer distance is formed by performing the charging step and the discharging step.

In the discharge step, only one of the surfaces of the positive electrode current collector (the surface facing the counter electrode) causes the reaction. Therefore, in the case where the positive electrode active material is formed on both surfaces of the positive electrode current collector, the positive electrode in which the anion formed on the non-reacted side surface is inserted by rotating the positive electrode halfway after the discharge process is completed The discharge treatment may be performed again on the active material.

Although the discharge rate in a discharge process is not specifically limited, It is preferable that it is 0.05-10C, and it is more preferable that it is 0.1-5C.
When the charge rate is less than 0.05C, it takes a long time for the discharging process, which is not preferable from the viewpoint of manufacturing efficiency. On the other hand, when the discharge rate exceeds 10 C, the anion elimination reaction may not proceed sufficiently.

In addition, it is preferable to form nanobubbles in the positive electrode active material by the charging step and the discharging step. Nanobubbles are fine pores that enable insertion and desorption of anions constituting a lithium salt in the positive electrode active material. Therefore, the charge / discharge capacity of the electricity storage device using the positive electrode active material in which the nanobubbles are formed as a positive electrode can be increased.

The anion inserted into the positive electrode active material in the charging process is desorbed from the positive electrode active material in the discharge process. At this time, the space where the anion was inserted is maintained as it is, so that the anion is inserted. Fine pores (nanobubbles) that can be detached are formed.

Next, the cell manufacturing process will be described.
In the cell production process, a cell is produced by combining the positive electrode that has undergone the discharge process and the pre-doped negative electrode.
Specifically, for example, a positive electrode and a pre-doped negative electrode that have undergone a discharge process are disposed facing each other through a separator, a non-aqueous electrolyte is added, and the cell is manufactured by sealing with an exterior member.

Note that the non-aqueous electrolyte used in the above-described charging process and discharging process can be used as the non-aqueous electrolyte used in the cell manufacturing process.
In addition, about preferable things, such as a separator and an exterior member, are explained in full detail in description of the electrical storage device of this invention.

In each step constituting the method for manufacturing an electricity storage device of the present invention, when a non-aqueous electrolyte is handled, it is preferable to work in an environment having a dew point of −35 ° C. or lower, and more preferably −60 ° C. or lower.
When a non-aqueous electrolyte is handled in an environment where the dew point exceeds -35 ° C, the lithium salt constituting the non-aqueous electrolyte may react with moisture in the environment and decompose and deteriorate.

An electricity storage device can be manufactured by connecting a single cell or a plurality of cells manufactured in the cell manufacturing process in any combination.
FIG. 4 is a cross-sectional view schematically showing an example of an electricity storage device manufactured by the method for manufacturing an electricity storage device of the present invention. The power storage device 1 shown in FIG. 4 includes a single cell 70 in which a positive electrode 20 and a pre-doped negative electrode 40 that have undergone a discharge process are immersed in a nonaqueous electrolyte solution 80 via a separator 90 and covered with an exterior member 71. ing.

Then, the electrical storage device of this invention is demonstrated.
In the electricity storage device of the present invention, a positive electrode active material that is a carbonaceous material is formed on a foil that separates a non-aqueous electrolyte between the front and back sides, and an insertion / desorption of an anion constituting a lithium salt is formed inside the positive electrode active material. A negative electrode active material that is a carbonaceous material is formed on a nanobubble positive electrode in which nanobubbles, which are fine pores that can be separated, are formed, and a foil that separates the non-aqueous electrolyte between the front and back surfaces, and the negative electrode active material And a pre-doped negative electrode subjected to lithium ion pre-doping.

The electricity storage device of the present invention includes, as a positive electrode, a nanobubble positive electrode in which nanobubbles are formed inside a positive electrode active material, and a negative electrode as a pre-doped negative electrode in which lithium ion pre-doping is performed on a negative electrode active material. Since the positive electrode active material in which nanobubbles are formed has many sites where anion can be inserted and released, the charge / discharge capacity of the electricity storage device can be increased.
Further, by using a negative electrode active material that has been pre-doped with lithium ions, more lithium is always inserted into the negative electrode than the amount of anions inserted into the positive electrode. For this reason, even when the electricity storage device is completely discharged, lithium is inserted into the negative electrode, and the electric potential of the negative electrode can be stabilized. Therefore, even when charging / discharging is repeated, deterioration of the negative electrode associated with charging / discharging can be suppressed, and the number of times that the electricity storage device can be used can be increased. In addition, since the potential fluctuation of the negative electrode can be almost ignored, the charge / discharge reaction can be performed using most of the positive electrode capacity, so that the capacity utilization rate and the energy density can be improved.

Moreover, the electrical storage device of this invention uses the foil which isolate | separates nonaqueous electrolyte solution between front and back as a collector. Since this is a foil not subjected to pore formation processing or the like, the manufacturing cost can be reduced, and an inexpensive product can be provided.
The distance from the current collector to the active material when the positive electrode and the negative electrode are made using a foil that separates the non-aqueous electrolyte between the front and back, compared to the case where a foil that has been subjected to pore formation processing is used. Therefore, unevenness is hardly generated in the insertion / release reaction of anions and lithium ions.
Furthermore, since it is not necessary to form pores by using a foil that separates the non-aqueous electrolyte between the front and back surfaces, conductivity and strength can be ensured even if a thin foil is used, and the size of the electricity storage device can be reduced. Can be small.

The electricity storage device of the present invention can be manufactured, for example, by the above-described method for manufacturing the electricity storage device of the present invention. In the case where the positive electrode 20 that has undergone the discharging process and constitutes the electric storage device 1 shown in FIG. 4 is a nanobubble positive electrode, it corresponds to the electric storage device of the present invention.

As the positive electrode current collector constituting the electricity storage device of the present invention, the same positive electrode current collector as mentioned in the method for producing an electricity storage device of the present invention can be preferably used.

As the negative electrode current collector constituting the electricity storage device of the present invention, the same negative electrode current collector as mentioned in the method for producing an electricity storage device of the present invention can be preferably used.

In the electricity storage device of the present invention, for example, a nanobubble positive electrode and a pre-doped negative electrode are arranged facing each other through a separator, and the nano-bubble positive electrode, the pre-doped negative electrode and the separator are in a non-aqueous electrolyte containing a lithium salt and a non-aqueous solvent. The nanobubble positive electrode, the pre-doped negative electrode, the separator, and the nonaqueous electrolytic solution are covered with an exterior member so that the nonaqueous electrolytic solution is not exposed to the atmosphere.

As the exterior member, a metal can, a ceramic, an aluminum laminate film, or the like can be used.
Examples of the metal constituting the metal can include aluminum and stainless steel, and the inner surface of the metal can may be subjected to an insulating coating treatment such as resin and alumite as necessary.

As the separator constituting the cell, a porous film made of a polymer such as cellulose or polyolefin such as polyethylene can be used.

Although the thickness of a separator is not specifically limited, It is preferable that it is 1-100 micrometers, It is more preferable that it is 5-50 micrometers, It is further more preferable that it is 10-30 micrometers.
When the thickness of the separator is less than 1 μm, defects such as pinholes are likely to occur in the separator. On the other hand, if the thickness of the separator exceeds 100 μm, the internal resistance of the electricity storage device increases, which may adversely affect the charge / discharge characteristics and cycle characteristics of the electricity storage device.

As the non-aqueous electrolyte, the non-aqueous electrolyte described in the method for producing an electricity storage device of the present invention can be suitably used.

If necessary, the power storage device of the present invention may be combined with an overcharge protection circuit, an overdischarge protection circuit, a temperature sensor, or the like.

The nanobubble positive electrode is preferably produced by the charging step and the discharging step described in the method for manufacturing an electricity storage device of the present invention.
By producing the nanobubble positive electrode by the charging step and the discharging step described in the method for manufacturing the electricity storage device of the present invention, it is not necessary to perform a process of forming nanobubbles on the positive electrode active material inside the electricity storage device.
Since there is no need to arrange the lithium supply source, support and electrode inside the electricity storage device for the production of the nanobubble positive electrode inside the electricity storage device, the dead space is reduced by the arrangement space of the lithium supply source, support and electrode. It is possible to increase the weight of the active material inside the electricity storage device and improve the energy density of the electricity storage device.
In addition, when nanobubble formation for the positive electrode active material is performed inside the electricity storage device, it is considered that the lithium supply source remains inside the electricity storage device, lithium dendrite is precipitated, and lithium is floated to cause a short circuit. On the other hand, in the electricity storage device having the above-described configuration, the lithium supply source is not disposed inside the electricity storage device, so that precipitation of lithium dendrite can be suppressed.

The pre-doped negative electrode is preferably produced by the charging step described in the method for producing an electricity storage device of the present invention.
Since there is no need to arrange the lithium supply source, support and electrode inside the electricity storage device to make the pre-doped negative electrode inside the electricity storage device, the dead space is reduced by the arrangement space of the lithium supply source, support and electrode. It is possible to increase the weight of the active material inside the electricity storage device and improve the energy density of the electricity storage device.
In addition, when pre-doping lithium ions into the negative electrode active material inside the electricity storage device, if the lithium supply source remains inside the electricity storage device, highly active metallic lithium may remain inside the electricity storage device, causing a short circuit. It will be in the state which has. On the other hand, in the electricity storage device having the above-described configuration, the lithium supply source is not disposed inside the electricity storage device, so that precipitation of lithium dendrite can be suppressed.

Another example of the electricity storage device of the present invention is shown.
FIG. 5 is a cross-sectional view schematically showing another example of the electricity storage device of the present invention. Moreover, FIG. 6 is sectional drawing which shows typically another example of the electrical storage device of this invention.
The power storage device of the present invention is composed of a single cell 75 having a structure in which a plurality of nanobubble positive electrodes 24 and pre-doped negative electrodes 42 are stacked with a separator 91 interposed therebetween, for example, as the power storage device 2 shown in FIG. May be. Further, as in the electricity storage device 3 illustrated in FIG. 6, a plurality of cells 76 in which the nanobubble positive electrode 25 and the pre-doped negative electrode 43 are arranged via the separator 92 may be connected.

Below, the manufacturing method of the electrical storage device of this invention and the effect of an electrical storage device are enumerated.
(1) In the manufacturing method of the electrical storage device of this invention, since a positive electrode and a negative electrode are not processed separately, a manufacturing process can be simplified. Furthermore, in the charging step, the positive electrode and the negative electrode do not need to have a laminated structure.
Further, in the charging process, since the amount of current and the electrode position can be monitored and adjusted, the uniformity of lithium ion pre-doping in the negative electrode can be achieved. Furthermore, the positive electrode treatment in which an anion is inserted into the positive electrode active material can be performed uniformly at the same time.
In addition, since a lithium supply source used for lithium ion pre-doping does not exist in the electricity storage device, generation of lithium dendrite can be suppressed, and safety can be said to be high.
Therefore, the method for manufacturing an electricity storage device of the present invention makes it possible to manufacture an electricity storage device with high safety and high capacity at a low cost and in a short time.

(2) The electricity storage device of the present invention includes a nanobubble positive electrode in which nanobubbles, which are fine pores capable of inserting and desorbing anions constituting a lithium salt, are formed in the positive electrode active material, and lithium ions in the negative electrode active material. It is comprised from the pre dope negative electrode by which the pre dope was performed. Therefore, it has a high charge / discharge capacity and energy density.
In addition, since the electricity storage device of the present invention uses a foil that separates the non-aqueous electrolyte between the front and back surfaces of the current collector, it is not necessary to subject the foil to fine processing such as pore formation processing, thereby suppressing manufacturing costs. be able to. In addition, since it is not necessary to form pores, the conductivity and strength can be ensured even when a thin foil is used, so that the size of the electricity storage device can be reduced.

(Example)
Examples in which the present invention is disclosed more specifically are shown below. In addition, this invention is not limited only to these Examples.

Example 1
(A) Charging step (a-1) Preparation of positive electrode Graphite powder as a positive electrode active material [crushed graphite material (ET-10) manufactured by Ibiden Co., Ltd. (D50 = 1.5 μm)], as conductive aid A positive electrode active material slurry was obtained by sufficiently mixing acetylene black, a styrene butadiene rubber (SBR) copolymer binder as a binder, carboxymethyl cellulose (CMC), and ion-exchanged water as a solvent.
Subsequently, the positive electrode active material slurry is dried on a 30 μm thick aluminum foil (a foil that separates the non-aqueous electrolyte between the front and back surfaces) using a Baker type applicator, and the thickness of the positive electrode active material layer after drying is reduced. It apply | coated only to one side so that it might be set to 30 micrometers.
The aluminum foil coated with the positive electrode active material slurry was dried at 60 ° C. for 10 minutes, then heated under reduced pressure at 120 ° C. for 10 hours and at 200 ° C. for 17 hours, and dried under reduced pressure. After drying, a positive electrode was prepared by punching into a coin shape so that the area where the positive electrode active material was formed was Φ1.5 cm.

(A-2) Preparation of Negative Electrode Graphite powder as a negative electrode active material [crushed graphite material (ET-10) manufactured by IBIDEN Co., Ltd. (D50 = 1.5 μm)], acetylene black as a conductive auxiliary agent, as a binder The SBR copolymer binder, CMC, and ion-exchanged water as a solvent were sufficiently mixed to obtain a negative electrode active material slurry.
The negative electrode active material slurry is dried on a copper foil having a thickness of 60 μm (a foil that separates the nonaqueous electrolyte between the front and back surfaces) using a baker-type applicator, and the thickness of the negative electrode active material layer after drying becomes 50 μm. It was applied only on one side.
The copper foil coated with the negative electrode active material slurry was dried at 60 ° C. for 10 minutes, and then heated under reduced pressure at 120 ° C. for 10 hours and at 200 ° C. for 17 hours to dry under reduced pressure. After drying, a negative electrode was prepared by punching into a coin shape so that the area where the negative electrode active material was formed was Φ1.5 cm.

(A-3) Charging step Non-aqueous electrolyte [LiPF ₆ 4M solution] so that the positive electrode obtained in (a-1) and the negative electrode obtained in (a-2) do not contact each other. (Solvent is DMC)]. Subsequently, the positive electrode and the negative electrode were connected to a charge / discharge tester (Bio-Logic, VMP3 type), and the temperature of 1C was adjusted to 25 ° C. until the potential of the positive electrode was 5.18 V (vs Li / Li ⁺ ). The battery was charged at the charge rate. At this time, the potential of the negative electrode was 0.55 V (vs Li / Li ⁺ ). After completion of charging, an anion-inserted positive electrode and a pre-doped negative electrode were obtained.
FIG. 7 shows potential changes of the positive electrode and the negative electrode in the charging process.
In the charging process in FIG. 7, the potential between [positive electrode and negative electrode] is shown, and the vertical axis shows the potential of each electrode with respect to the lithium reference electrode. In FIG. 7, A1, A2, and A3 indicate the potential of the positive electrode, B1 and B2 indicate the potential of the negative electrode, and C1 and C2 indicate the transition of the potential of the lithium-containing electrode, respectively. Table 1 shows the potential of each electrode at each stage.

(B) Negative Electrode Replacement Step The pre-doped negative electrode obtained in the above (a) charging step was recovered, and a lithium-containing electrode was placed in the non-aqueous electrolyte instead.
As the lithium-containing electrode, a negative electrode made of a carbonaceous material pre-doped with lithium ions, prepared separately from the pre-doped negative electrode prepared by the charging step (a) was used.

(C) Discharge process The anion insertion positive electrode obtained by the above-mentioned (a) charge process and the lithium-containing electrode arranged by the above-mentioned (b) negative electrode exchange process are put into a charge / discharge tester (Bio-Logic, VMP3 type). It connected, and it discharged at the discharge rate of 1C until the electric potential of 25 degreeC and the positive electrode became 3.08V (vs Li / Li ^<+> ), and the positive electrode which passed through the discharge process was obtained.
In this discharge step, since the lithium ions and anions consumed in the charging step (a) are released into the non-aqueous electrolyte solution, the non-aqueous electrolyte solution was regenerated.
FIG. 7 shows potential changes of the anion-inserted positive electrode and the lithium-containing electrode in the discharging process.
In the charging step in FIG. 7, the potential between [positive electrode and lithium-containing electrode] is shown, and the vertical axis shows the potential of each electrode with respect to the lithium reference electrode. The horizontal axis indicates the time from the start of the charging process, and the time required for the negative electrode replacement process is ignored. In FIG. 7, A1, A2, and A3 indicate the potential of the positive electrode, B1 and B2 indicate the potential of the negative electrode, and C1 and C2 indicate the transition of the potential of the lithium-containing electrode, respectively. Table 1 shows the potential of each electrode at each stage.

(D) Cell preparation step The pre-doped negative electrode obtained by the above-mentioned (a) charging step and the positive electrode obtained by the above-mentioned (c) discharging step are disposed facing each other through a cellulose separator (thickness: 35 μm), and non-aqueous After including a 4M LiPF ₆ solution (solvent: DMC) as the electrolyte, an R2032-type coin cell was produced.
In addition, the said (a-3) process, the said (b) process, the said (c) process, and the said (d) process were performed in the dry atmosphere whose dew point is -60 degrees C or less.

In Table 1, although simply described as a positive electrode, the positive electrode in A2 is an anion-inserted positive electrode, and the positive electrode in A3 is a positive electrode that has undergone a discharging step. The same applies to the negative electrode, and the negative electrode in B2 is a pre-doped negative electrode.

As shown in FIG. 7 and Table 1, the potential of the positive electrode subjected to the discharging step was 3.08 V (vs Li / LI ⁺ ), and the potential of the pre-doped negative electrode was 0.55 V (vs Li / LI ⁺ ).
The positive electrode that has undergone the discharging process has a value substantially equal to the potential (3.06 V (vs Li / LI ⁺ )) of the positive electrode before the start of the charging process, and thus was inserted into the positive electrode active material in the charging process. It is considered that most of the anions are eliminated. On the other hand, in the pre-doped negative electrode, the potential is greatly reduced as compared with the potential (3.19 V (vs Li / LI ⁺ )) of the negative electrode before the start of the charging process. Therefore, pre-doping of lithium ions into the negative electrode active material Was confirmed to be in progress. Therefore, even when the electricity storage device is completely discharged, lithium is inserted into the pre-doped negative electrode, so that the potential of the negative electrode can be stabilized in a low state, and the negative electrode when repeated charging and discharging is performed. It was found that deterioration can be suppressed.
In addition, since the produced electricity storage device does not require a space for accommodating a lithium supply source and a support that supports the lithium supply source, by filling the space inside the electricity storage device with a positive electrode active material and a negative electrode active material, It was found that the energy density can be increased. Further, since the lithium supply source does not remain inside the electricity storage device, it can be said that a highly safe electricity storage device was obtained.

1, 2, 3 Power storage device 10 Cathode 11 Cathode active material 12 Cathode current collector 15 Anion-inserted cathode 16 Cathode active material 20 with anion inserted Cathode 21 after discharge process Cathode active material 24, 25 with increased interlayer distance Nanobubbles Positive electrode 30 Negative electrode 31 Negative electrode active material 32, 52 Negative electrode current collector 40, 42, 43 Pre-doped negative electrode 41 Lithium pre-doped negative electrode active material 50 Lithium-containing electrode 51 Lithium-containing compound 60, 80 Non-aqueous electrolyte 70, 75, 76 Cell 71 Exterior member 90, 91, 92 Separator 100 Charge / discharge tester

Claims (4)

In a non-aqueous electrolyte containing a lithium salt and a non-aqueous solvent, the positive electrode on which a positive electrode active material that is a carbonaceous material is formed and a negative electrode on which a negative electrode active material that is a carbonaceous material is formed are electrically connected. Charging to form an anion-inserted positive electrode by inserting the anion constituting the lithium salt into the positive electrode active material by charging, and pre-doping lithium ion into the negative electrode active material to produce a pre-doped negative electrode Process,
Collecting the pre-doped negative electrode and replacing it with a lithium-containing electrode;
A discharge step of electrically connecting the anion-inserted positive electrode and the lithium-containing electrode and desorbing the anion from the inside of the positive electrode active material by discharging in the non-aqueous electrolyte;
A method for producing an electricity storage device, comprising: a cell production step of producing a cell by combining the positive electrode subjected to the discharge step and the pre-doped negative electrode. 2. The nanobubble positive electrode in which nanobubbles, which are fine pores capable of inserting and desorbing anions constituting a lithium salt, are formed in the positive electrode active material in the charging step and the discharging step. Manufacturing method for electric storage device. The method for manufacturing an electricity storage device according to claim 1, wherein the lithium-containing electrode is made of a carbonaceous material pre-doped with lithium ions. The positive electrode active material is formed on a foil that separates the non-aqueous electrolyte between the front and back sides,
The said negative electrode active material is a manufacturing method of the electrical storage device in any one of Claims 1-3 currently formed on the foil which isolate | separates a non-aqueous electrolyte between front and back .

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