JP2018152519A - Nonaqueous power storage element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous power storage element which is high in discharge capacity and superior in discharge rate characteristic.SOLUTION: A nonaqueous power storage element 10 comprises: a positive electrode 11 including a positive electrode active material which allows an anion to go thereinto and go out thereof; a negative electrode 12 including a negative electrode active material; and a nonaqueous electrolyte solution. The positive electrode active material is porous carbon in which pores having three-dimensional cancellous structure are formed. The nonaqueous electrolyte solution contains a nonaqueous solvent, an electrolytic salt and an ionic liquid.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a non-aqueous power storage element.

  In recent years, with the miniaturization and high performance of portable devices, the characteristics of non-aqueous storage elements with high energy density have improved, and non-aqueous storage elements have become widespread. Furthermore, development of non-aqueous storage elements with higher capacity and superior safety has been promoted, and installation of non-aqueous storage elements in electric vehicles and the like has begun.

  As a non-aqueous storage element having a high energy density and suitable for high-speed charge / discharge, a so-called dual intercalation type non-aqueous storage element (dual ion battery) is expected to be put to practical use (for example, see Patent Document 1).

  In the dual ion battery, carbon is used as the positive electrode active material, carbon or the like is used as the negative electrode active material, and a solution in which a lithium salt is dissolved in a nonaqueous solvent is used as the nonaqueous electrolytic solution. In the dual ion battery, the anion and cation in the non-aqueous electrolyte are inserted into the positive electrode active material and the negative electrode active material, respectively, during charging, and during discharge, the anion and cation are non-aqueous from the positive electrode active material and the negative electrode active material, respectively. Desorbs into the electrolyte.

  On the other hand, in a lithium ion capacitor, a configuration is disclosed in which a supporting electrolyte made of an ionic liquid or a lithium salt is used as an electrolytic solution containing an organic solvent (see, for example, Patent Document 2).

  However, even when carbon is used as the positive electrode active material and a supporting electrolyte made of an ionic liquid or lithium salt is used as the electrolytic solution containing an organic solvent, the discharge capacity during high-speed charge / discharge is insufficient. There is a problem that the rate characteristics are insufficient.

  An object of the present invention is to provide a non-aqueous energy storage device having a high discharge capacity and excellent discharge rate characteristics.

  One embodiment of the present invention includes a positive electrode including a positive electrode active material capable of inserting or desorbing anions, a negative electrode including a negative electrode active material, and a non-aqueous electrolyte in a non-aqueous power storage element. The active material is porous carbon in which pores having a three-dimensional network structure are formed, and the non-aqueous electrolyte includes a non-aqueous solvent, an electrolyte salt, and an ionic liquid.

  According to the present invention, it is possible to provide a non-aqueous energy storage device having a high discharge capacity and excellent discharge rate characteristics.

It is a figure which shows an example of the adsorption isotherm used for derivation | leading-out of the mesopore content rate of porous carbon. It is the schematic which shows an example of the non-aqueous electrical storage element of this embodiment. It is the schematic explaining the basic composition of the non-aqueous electrical storage element of FIG. 6 is a graph showing the measurement results of the discharge capacity of the non-aqueous storage element of Example 1 and Comparative Example 1.

(Non-aqueous storage element)
The non-aqueous electricity storage device of this embodiment includes a positive electrode including a positive electrode active material capable of inserting or desorbing anions, a negative electrode including a negative electrode active material, and a non-aqueous electrolyte. At this time, the positive electrode active material is porous carbon in which pores having a three-dimensional network structure are formed, and the nonaqueous electrolytic solution includes a nonaqueous solvent, an electrolyte salt, and an ionic liquid.

  The non-aqueous electricity storage device of this embodiment preferably includes a separator, and further includes other members as necessary.

  In the non-aqueous storage element of the present embodiment, when a non-aqueous electrolyte containing an ionic liquid is applied to a lithium ion capacitor in which a positive electrode containing a conventional activated carbon is used, the viscosity of the non-aqueous electrolyte increases. This is based on the knowledge that the mobility of ions in the micropores of the activated carbon is remarkably deteriorated, and as a result, the discharge rate characteristics are remarkably lowered.

  The non-aqueous electricity storage device of this embodiment uses a porous carbon in which pores having a three-dimensional network structure are formed as a positive electrode active material, and the resistance is reduced by using a non-aqueous electrolyte containing an ionic liquid. Can be made. Furthermore, the nonaqueous electrical storage element of this embodiment can suppress the fall of the ion mobility by the viscosity which a nonaqueous electrolyte solution becomes high with the pore which porous carbon has. As a result, the non-aqueous storage element of this embodiment has high discharge rate characteristics.

  In the non-aqueous storage element of the present embodiment, a positive electrode containing porous carbon in which pores having a three-dimensional network structure are formed as a positive electrode active material, and a non-aqueous electrolyte solution containing an ionic liquid is used. The raw material of porous carbon, its production method, other characteristics, etc. are not particularly limited. Further, other components such as the negative electrode are not particularly limited.

  Hereinafter, the components of the nonaqueous storage element of this embodiment will be described in detail.

<Positive electrode>
The positive electrode is not particularly limited as long as it contains a positive electrode active material, and can be appropriately selected according to the purpose. For example, a positive electrode including a positive electrode material containing a positive electrode active material on a positive electrode current collector is used. Can be mentioned.

  There is no restriction | limiting in particular as a shape of a positive electrode, According to the objective, it can select suitably, For example, flat form etc. are mentioned.

-Positive electrode material-
The positive electrode material includes a positive electrode active material, and further includes a conductive additive, a binder, and the like as necessary.

--- Positive electrode active material-
As the positive electrode active material, porous carbon in which pores having a three-dimensional network structure are formed is used.

---- Porous carbon ---
In the porous carbon, the positive and negative electrolyte ions are present in pairs on both sides of the interface between the pores and the wall portion separating the adjacent pores, whereby a charge double layer is formed. For this reason, the movement of the electrolyte ions present in pairs is faster than the movement of the generated electrolyte ions after a sequential discharge reaction with the electrode active material, and the power supply capacity is also less than the total pore volume. However, it turns out that it depends on the surface area of a pore.

  Next, the crystallinity of porous carbon will be described. The time constant (slow response at the time of charging / discharging) of the non-aqueous storage element depends not only on the capacitance of the non-aqueous electrolyte but also on the resistance value of the porous carbon that makes ohmic contact with the non-aqueous electrolyte. Furthermore, since the anion repeatedly inserts and desorbs from the porous carbon, the porous carbon may be deteriorated. For this reason, it is preferable that the crystallinity of the porous carbon is appropriately determined so that the porous carbon has a strength that can withstand deterioration.

  Note that it is not necessary that all the parts of the porous carbon have a crystal structure, and an amorphous part may exist in part. In addition, the porous carbon may be all amorphous.

  The pores preferably include mesopores. Therefore, the pores may contain micropores or may not contain micropores. Here, when producing porous carbon, a volatile substance is usually released when the organic substance is carbonized. Therefore, since the porous carbon usually has micropores as a release trace, it is difficult to obtain porous carbon having no micropores. On the other hand, mesopores are usually formed intentionally. Generally, after forming a muscle material soluble in acid (or alkali) and carbon or an organic material as its raw material, traces of the muscle material dissolved with acid (or alkali) become mesopores. .

  Here, in the present specification and claims, pores having a pore diameter of less than 2 nm are referred to as micropores, and pores having a pore diameter of 2 nm to 50 nm are referred to as mesopores.

  Since the size of the electrolyte ions is not less than 0.5 nm and not more than 2 nm, it is difficult to say that the micropores contribute much to the movement of the electrolyte ions. Therefore, mesopores are important in order for electrolyte ions to move smoothly.

  Incidentally, it is said that the average pore diameter of micropores in activated carbon is about 1 nm. For this reason, electrolyte ions are adsorbed to the micropores of the activated carbon without exception, accompanied by heat generation, that is, a decrease in enthalpy.

  The mesopores preferably have a three-dimensional network structure. Thereby, electrolyte ion can move smoothly.

The BET specific surface area of the porous carbon is preferably 50 m ² / g or more, and more preferably 800 m ² / g or more. When the BET specific surface area of the porous carbon is 50 m ² / g or more, the mesopores are sufficiently formed and the anions are sufficiently inserted, so that the discharge capacity and discharge rate characteristics of the non-aqueous storage element are improved.

The BET specific surface area of the porous carbon is preferably 2,000 m ² / g or less, and more preferably 1,800 m ² / g or less. When the BET specific surface area of the porous carbon is 2,000 m ² / g or less, the mesopores are sufficiently formed and the anions are sufficiently inserted, so that the discharge capacity of the nonaqueous storage element is increased.

  The BET specific surface area of the porous carbon is obtained, for example, by measuring the adsorption isotherm with an automatic specific surface area / pore distribution measuring device TriStar II 3020 (manufactured by Shimadzu Corporation) and then by the BET (Brunauer, Emmett, Teller) method. Can do.

  The total pore volume of the porous carbon is preferably 0.2 mL / g or more and 2.3 mL / g or less, and more preferably 0.2 mL / g or more and 1.7 mL / g or less. When the total pore volume of the porous carbon is 0.2 mL / g or more, the mesopores rarely become independent, the anions easily move, and the discharge capacity of the nonaqueous storage element increases. On the other hand, when the total pore volume of the porous carbon is 2.3 mL / g or less, the structure of the porous carbon does not become bulky, so that the energy density of the positive electrode is increased, and the discharge per unit volume of the nonaqueous storage element is increased. Capacity increases. In addition, since the wall portion that separates adjacent mesopores is not thinned, the shape of the wall portion can be maintained even when insertion and removal of anions are repeated, and the charge / discharge characteristics of the nonaqueous storage element are improved.

  The total pore volume of the porous carbon is obtained, for example, by measuring the adsorption isotherm with an automatic specific surface area / pore distribution measuring device TriStarII3020 (manufactured by Shimadzu Corporation) and then by the BJH (Barrett, Joyner, Hallender) method. be able to.

  The mesopore content in the pores of the porous carbon is preferably 25% or more and 80% or less, and more preferably 30% or more and 60% or less. When the mesopore content in the pores of the porous carbon is 25% or more, mesopores having a three-dimensional network structure are sufficiently formed, so that anions easily move, and the discharge capacity of the nonaqueous storage element Becomes higher. Moreover, since the mesopore content in the pores of the porous carbon is 80% or less, mesopores are sufficiently formed inside the porous carbon, and can be utilized up to the inside of the porous carbon. The discharge capacity and discharge rate characteristics of the non-aqueous storage element are improved.

The mesopore content in the pores of the porous carbon is, for example, after measuring an adsorption isotherm (for example, see FIG. 1) with an automatic specific surface area / pore distribution measuring device TriStarII3020 (manufactured by Shimadzu Corporation), Formula {(Adsorption amount of p / p ₀ = 0.96) − (Adsorption amount of p / p ₀ = 0.3)} / (Adsorption amount of p / p ₀ = 0.96) × 100 1)
Can be derived.

The adsorption amount of p / p ₀ = 0.3 represents the adsorption amount of nitrogen gas derived from the micropores of porous carbon, and the adsorption amount of p / p ₀ = 0.96 represents the microscopic amount of porous carbon. The adsorption amount of nitrogen gas derived from pores and mesopores is shown.

  As porous carbon, you may synthesize | combine suitably and may use a commercial item.

  Examples of commercially available products of porous carbon include Knobel (registered trademark) (manufactured by Toyo Tanso Co., Ltd.).

  The method for producing porous carbon is not particularly limited and may be appropriately selected depending on the intended purpose.For example, after forming and carbonizing a muscle material having a three-dimensional network structure and an organic substance, an acid is formed. Or the method of dissolving a muscle material with an alkali is mentioned. In this case, the trace in which the muscle material is dissolved becomes a mesopore having a three-dimensional network structure.

  The material constituting the muscle is not particularly limited as long as it can be dissolved in acid or alkali, and can be appropriately selected according to the purpose. For example, metal, metal oxide, metal salt, metal Contains organic compounds.

  The organic substance is not particularly limited as long as it can be carbonized, and can be appropriately selected according to the purpose.

  In addition, since an organic substance generally emits a volatile substance when carbonized, micropores are formed as emission traces. For this reason, it is difficult to produce porous carbon having no micropores.

--Binder--
The binder is not particularly limited as long as it is a material that is stable with respect to the solvent, non-aqueous electrolyte, and applied potential used in manufacturing the positive electrode, and can be appropriately selected according to the purpose. Fluorine-based binders such as vinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE), ethylene-propylene-butadiene rubber (EPBR), styrene-butadiene rubber (SBR), isoprene rubber, acrylate latex, carboxymethylcellulose (CMC), Examples include methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyacrylic acid, polyvinyl alcohol, alginic acid, oxidized starch, phosphate starch, and casein. These may be used alone or in combination of two or more. Among these, fluorine-based binders such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE), acrylate latex, and carboxymethyl cellulose (CMC) are preferable.

--Conductive aid--
As a conductive support agent, carbonaceous materials, such as metal materials, such as copper and aluminum, carbon black, acetylene black, a carbon nanotube, etc. are mentioned, for example. These may be used alone or in combination of two or more.

-Positive electrode current collector-
There is no restriction | limiting in particular as a material, a shape, a magnitude | size, and a structure of a positive electrode electrical power collector, According to the objective, it can select suitably.

  The material of the positive electrode current collector is not particularly limited as long as it is a conductive material and is stable with respect to the applied potential, and can be appropriately selected according to the purpose. For example, stainless steel, nickel, aluminum , Titanium, tantalum and the like. Among these, stainless steel and aluminum are particularly preferable.

  There is no restriction | limiting in particular as a shape of a positive electrode electrical power collector, According to the objective, it can select suitably.

  The size of the positive electrode current collector is not particularly limited as long as it is a size that can be used for a non-aqueous storage element, and can be appropriately selected according to the purpose.

<Method for producing positive electrode>
The positive electrode is added to the positive electrode active material, if necessary, a binder, a conductive additive, a solvent, etc., and applied to the positive electrode current collector in a slurry state, and then dried, It can be manufactured by forming a positive electrode material.

  There is no restriction | limiting in particular as a solvent, According to the objective, it can select suitably, For example, an aqueous solvent, an organic solvent, etc. are mentioned.

  Examples of the aqueous solvent include water and alcohol.

  Examples of the organic solvent include N-methyl-2-pyrrolidone (NMP) and toluene.

  In addition, the composition for positive electrodes which added the binder, the conductive support agent, etc. to the positive electrode active material as needed can be roll-molded into a sheet electrode, or can be compressed into a pellet electrode.

<Negative electrode>
The negative electrode is not particularly limited as long as it contains a negative electrode active material, and can be appropriately selected according to the purpose. For example, a negative electrode including a negative electrode material containing a negative electrode active material on a negative electrode current collector is used. Can be mentioned.

  There is no restriction | limiting in particular as a shape of a negative electrode, According to the objective, it can select suitably, For example, flat form etc. are mentioned.

-Negative electrode material-
The negative electrode material includes a negative electrode active material, and further includes a conductive additive, a binder, and the like as necessary.

--- Negative electrode active material-
The negative electrode active material is not particularly limited as long as it can occlude or release cations in the nonaqueous electrolytic solution, and can be appropriately selected according to the purpose. For example, it absorbs or releases lithium ions. Carbonaceous materials, metal oxides, metals that can be alloyed with lithium or alloys thereof, composite alloy compounds with lithium, lithium metal nitride, and the like. These may be used alone or in combination of two or more. Among these, a carbonaceous material and lithium titanate are preferable from the viewpoint of safety and cost.

  There is no restriction | limiting in particular as a carbonaceous material, According to the objective, it can select suitably, For example, graphite (graphite), the thermal decomposition thing of the organic substance on various thermal decomposition conditions, etc. are mentioned.

  Examples of graphite (graphite) include coke, artificial graphite, and natural graphite. Among these, artificial graphite and natural graphite are preferable.

  Examples of the metal oxide include antimony tin oxide and silicon monoxide.

  Examples of the metal that can be alloyed with lithium include lithium, aluminum, tin, silicon, and zinc.

  Examples of the composite alloy compound with lithium include lithium titanate.

  Examples of the lithium metal nitride include cobalt lithium nitride.

--Binder--
The binder is not particularly limited as long as it is a material that is stable with respect to the solvent and non-aqueous electrolyte used to produce the negative electrode, and the applied potential, and can be appropriately selected according to the purpose. Fluorine binders such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE), ethylene-propylene-butadiene rubber (EPBR), styrene-butadiene rubber (SBR), isoprene rubber, acrylate latex, carboxymethylcellulose (CMC) , Methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyacrylic acid, polyvinyl alcohol, alginic acid, oxidized starch, phosphoric acid starch, casein and the like. These may be used alone or in combination of two or more. Among these, fluorine-based binders such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE), styrene-butadiene rubber (SBR), and carboxymethyl cellulose (CMC) are preferable.

--Conductive aid--
As a conductive support agent, carbonaceous materials, such as metal materials, such as copper and aluminum, carbon black, acetylene black, a carbon nanotube, etc. are mentioned, for example. These may be used alone or in combination of two or more.

-Negative electrode current collector-
There is no restriction | limiting in particular as a material, a shape, a magnitude | size, and a structure of a negative electrode collector, According to the objective, it can select suitably.

  The material of the negative electrode current collector is a conductive material and is not particularly limited as long as it is stable with respect to the applied potential, and can be appropriately selected according to the purpose. For example, stainless steel, nickel, aluminum, Examples include copper. Among these, stainless steel, copper, and aluminum are particularly preferable.

  There is no restriction | limiting in particular as a shape of a negative electrode electrical power collector, According to the objective, it can select suitably.

  The size of the negative electrode current collector is not particularly limited as long as it is a size that can be used for a non-aqueous storage element, and can be appropriately selected according to the purpose.

<Method for producing negative electrode>
The negative electrode is added to the negative electrode active material, if necessary, by adding a binder, a conductive additive, a solvent, etc., and applying a slurry-like negative electrode material coating liquid on the negative electrode current collector, followed by drying, It can be manufactured by forming a negative electrode material.

  As the solvent, a solvent similar to the method for manufacturing the positive electrode can be used.

  In addition, if necessary, a negative electrode composition in which a binder, a conductive additive and the like are added to the negative electrode active material may be roll-molded to form a sheet electrode, or compression molded to a pellet electrode.

  Further, the negative electrode material can be formed by forming a thin film of a negative electrode active material on the negative electrode current collector by a technique such as vapor deposition, sputtering, or plating.

<Non-aqueous electrolyte>
The nonaqueous electrolytic solution is a mixed solution of a solution in which an electrolyte salt is dissolved in a nonaqueous solvent and an ionic liquid.

-Non-aqueous solvent-
There is no restriction | limiting in particular as a non-aqueous solvent, Although it can select suitably according to the objective, An aprotic organic solvent is used suitably.

  As the aprotic organic solvent, carbonate-based organic solvents such as chain carbonates and cyclic carbonates are used, and solvents having low viscosity are preferable. Among these, a chain carbonate is preferable because the solubility of the electrolyte salt is high.

  Examples of the chain carbonate include dimethyl carbonate (DMC), diethyl carbonate (DEC), and methyl ethyl carbonate (EMC).

  The content of the chain carbonate in the non-aqueous solvent is not particularly limited and can be appropriately selected depending on the purpose.

  Examples of the cyclic carbonate include propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate (BC), vinylene carbonate (VC), and fluoroethylene carbonate (FEC).

  When a mixed solvent of ethylene carbonate (EC) and methyl ethyl carbonate (EMC) is used as the non-aqueous solvent, the mixing ratio of ethylene carbonate (EC) and methyl ethyl carbonate (EMC) is not particularly limited. It can be appropriately selected depending on the case.

  As the non-aqueous solvent, an ester organic solvent such as a cyclic ester or a chain ester, an ether organic solvent such as a cyclic ether or a chain ether, or the like can be used as necessary.

  Examples of the cyclic ester include γ-butyrolactone (γ-BL), 2-methyl-γ-butyrolactone, acetyl-γ-butyrolactone, and γ-valerolactone.

  Examples of the chain ester include propionic acid alkyl ester, malonic acid dialkyl ester, acetic acid alkyl ester (methyl acetate (MA), ethyl acetate, etc.), formic acid alkyl ester (methyl formate (MF), ethyl formate, etc.) and the like. It is done.

  Examples of the cyclic ether include tetrahydrofuran, alkyltetrahydrofuran, alkoxytetrahydrofuran, dialkoxytetrahydrofuran, 1,3-dioxolane, alkyl-1,3-dioxolane, 1,4-dioxolane and the like.

  Examples of the chain ether include 1,2-dimethoxyethane (DME), diethyl ether, ethylene glycol dialkyl ether, diethylene glycol dialkyl ether, triethylene glycol dialkyl ether, and tetraethylene glycol dialkyl ether.

-Electrolyte salt-
The electrolyte salt is not particularly limited as long as it is a compound that dissolves in a non-aqueous solvent and exhibits high ionic conductivity, but a compound containing a halogen atom is preferable.

  Examples of the cation constituting the electrolyte salt include alkali metal ions, alkaline earth metal ions, tetraalkylammonium ions, spiro quaternary ammonium ions, and the like.

Examples of the anion constituting the electrolyte salt include Cl ⁻ , Br ⁻ , I ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N. _{^{-, (C 2 F 5 SO}} 2) 2 N - , and the like.

  As the electrolyte salt, it is preferable to use a lithium salt.

The lithium salt is not particularly limited. For example, lithium hexafluorophosphate (LiPF ₆ ), lithium perchlorate (LiClO ₄ ), lithium chloride (LiCl), lithium borofluoride (LiBF ₄ ), arsenic hexafluoride Lithium (LiAsF ₆ ), lithium trifluoromethanesulfonate (LiCF ₃ SO ₃ ), lithium bistrifluoromethylsulfonylimide (LiN (CF ₃ SO ₂ ) ₂ ), lithium bispentafluoroethylsulfonylimide (LiN (C ₂ F ₅ SO) ₂ ) ₂ ) and the like. These may be used alone or in combination of two or more. Among these, LiBF ₄ is particularly preferable from the viewpoint of the amount of anion inserted into the porous carbon.

  The concentration of the electrolyte salt in the non-aqueous electrolyte is preferably 0.5 mol / L or more and 6 mol / L or less, and 2 mol / L or more and 4 mol / L or less from the viewpoint of compatibility between the capacity and output of the non-aqueous storage element. It is more preferable that

-Ionic liquid-
Examples of the cation constituting the ionic liquid include tetraethylammonium ion, triethylmethylammonium ion, N, N, N-trimethyl-N-propylammonium ion, N, N-diethyl-N-methyl-methoxyethylammonium ion, 1 -Methyl-1-propylpyrrolidinium ion, 1-methyl-1-butylpyrrolidinium ion, 1-butyl-3-methylimidazolium ion, 1-methyl-3-butylimidazolium ion, 1-ethyl-3-methyl Imidazolium ion, 1-hexyl-3-methylimidazolium ion, 1-methyl-3-hexylimidazolium ion, 1-octyl-3-methylimidazolium ion, 1-methyl-3-octylimidazolium ion, 1- Ethyl-2,3-dimethyl Imidazolium ion, 1-butyl-2,3-dimethylimidazolium ion, 1-hexyl-2,3-dimethylimidazolium ion, N-methyl-N-propylpiperidinium ion, N-methyl-N-butylpiperidinium Ion, 1-ethylpyridinium ion, 1-butylpyridinium ion, 1-hexylpyridinium ion, tributyl-n-octylphosphonium ion, tetraphenylphosphonium ion, tetraethylphosphonium ion, tetra-n-octylphosphonium ion, methyltriphenylphosphonium ion , Isopropyltriphenylphosphonium ion, methoxycarbonylphosphonium ion, (1-naphthylmethyl) triphenylphosphonium ion, trimethylsulfonium ion, (2-cation Bokishiechiru) dimethyl sulfonium ion, diphenylmethyl sulfonium ion, tri -n- butyl sulfonium ion, tri -p- tolyl sulfonium ion, triphenylsulfonium ion, and the like cyclopropyl diphenyl sulfonium ion. Among these, N, N-diethyl-N-methyl-N-methoxyethylammonium ion and / or N-methyl-N-propylpyrrolidinium ion are particularly preferable.

Examples of the anion constituting the ionic liquid include PF ₆ ⁻ , PF ₃ (C ₂ F ₅ ) ₃ ⁻ , PF ₃ (CF ₃ ) ₃ ⁻ , BF ₄ ⁻ , BF ₂ (CF) ₂ ⁻ , and BF ₃ ( ^{_{CF 3) 2 -, AlCl 4}} -, N (FSO 2) 2 -, N (CF 3 SO 2) 2 -, N (C 2 F 5 SO 2) 2 -, CF 3 SO 3 - , and the like. Among these, bisfluorosulfonylimide ion (N (FSO ₂ ) ₂ ⁻ ) and / or bistrifluoromethanesulfonimide ion (N (CF ₃ SO ₂ ) ₂ ⁻ ) are particularly preferable.

  The content of the ionic liquid in the nonaqueous electrolytic solution is preferably 1 to 18% by mass, and more preferably 3 to 15% by mass. When the content of the ionic liquid in the non-aqueous electrolyte is 1% by mass or more, the discharge capacity and discharge rate characteristics of the non-aqueous power storage element are increased, and when the content is 18% by mass or less, the viscosity of the non-aqueous electrolyte is It becomes low and the discharge rate characteristic of a non-aqueous electrical storage element becomes high.

<Separator>
The separator is provided between the positive electrode and the negative electrode in order to prevent a short circuit between the positive electrode and the negative electrode.

  There is no restriction | limiting in particular as a material of a separator, a shape, a magnitude | size, and a structure, According to the objective, it can select suitably.

  Examples of the separator include paper such as kraft paper, vinylon mixed paper, synthetic pulp mixed paper, cellophane, polyethylene graft membrane, polyolefin nonwoven fabric such as polypropylene melt blown nonwoven fabric, polyamide nonwoven fabric, glass fiber nonwoven fabric, and micropore membrane.

  The separator preferably has a porosity of 50% or more from the viewpoint of holding the non-aqueous electrolyte.

  As the shape of the separator, since the porosity is high, the nonwoven fabric type is preferable to the thin film type having micropores.

  The average thickness of the separator is preferably 20 μm or more and 100 μm or less. When the average thickness of the separator is 20 μm or more, the amount of non-aqueous electrolyte retained is increased, and when it is 100 μm or less, the energy density of the non-aqueous storage element is improved.

  The size of the separator is not particularly limited as long as it is a size that can be used for a non-aqueous energy storage device, and can be appropriately selected according to the purpose.

  The structure of the separator may be a single layer structure or a laminated structure.

<Other members>
There is no restriction | limiting in particular as another member, According to the objective, it can select suitably, For example, an exterior can, a lead wire, etc. are mentioned.

<Method for producing non-aqueous energy storage device>
The non-aqueous electricity storage device of this embodiment can be manufactured by assembling, for example, a positive electrode, a negative electrode, a non-aqueous electrolyte, and a separator into an appropriate shape. At this time, if necessary, other members such as an outer can can be further used.

  There is no restriction | limiting in particular as a method of assembling a non-aqueous electrical storage element, It can select suitably from the methods employ | adopted normally.

<Shape of nonaqueous storage element>
There is no restriction | limiting in particular as a shape of the non-aqueous electrical storage element of this embodiment, Although it can select suitably according to the use from various shapes generally employ | adopted, For example, a sheet electrode and a separator Are a spiral cylinder type, an inside-out structure cylinder type in which a pellet electrode and a separator are combined, a coin type in which a pellet electrode and a separator are stacked, and the like.

  FIG. 3 shows an example of the non-aqueous electricity storage device of this embodiment.

  The nonaqueous storage element 10 includes a positive electrode 11, a negative electrode 12, a separator 13 holding a nonaqueous electrolyte, an outer can 14, a lead wire 15 of the positive electrode 11, and a lead wire 16 of the negative electrode 12. .

  Specific examples of the nonaqueous storage element 10 include a nonaqueous secondary battery and a nonaqueous capacitor.

  Next, the basic configuration of the non-aqueous storage element 10 will be described with reference to FIG.

  The positive electrode 11 includes, for example, an aluminum positive electrode current collector 11a, a porous carbon 11b (positive electrode active material) fixed on the positive electrode current collector 11a, a binder 11c that connects the porous carbons 11b, and a porous material. A conductive auxiliary agent 11d for providing a conductive path between the carbonaceous carbon 11b is provided.

  The negative electrode 12 includes, for example, a copper negative electrode current collector 12a, a carbon 12b (negative electrode active material) fixed on the negative electrode current collector 12a, a binder 12c that connects the negative electrode active materials 12b, and a negative electrode active material A conductive auxiliary agent 12d for providing a conductive path between 12b is provided.

  A separator 13 is disposed between the positive electrode 11 and the negative electrode 12, and the non-aqueous electrolyte N is held in the separator 13. The non-aqueous electrolyte N contains an anion A and a cation C, the anion A is inserted or desorbed between the layers of the porous carbon 11b, and the cation C is inserted or desorbed from the carbon 12b. Thereby, charging / discharging of the non-aqueous electrical storage element 10 is implemented.

In a non-aqueous storage element of a dual intercalation type, for example, when LiPF ₆ is used as an electrolyte salt, PF ₆ ⁻ in the non-aqueous electrolyte is inserted into the positive electrode active material, By inserting Li ⁺ into the negative electrode active material, the non-aqueous storage element is charged. On the other hand, PF ₆ ⁻ inserted into the positive electrode active material is desorbed into the non-aqueous electrolyte, and Li ⁺ inserted into the negative electrode active material is desorbed into the non-aqueous electrolyte, thereby discharging the non-aqueous storage element. Is implemented.

＜非水系蓄電素子の用途＞
本実施形態の非水電解液蓄電素子の用途としては、特に制限はなく、各種用途に用いることができ、例えば、ノートパソコン、ペン入力パソコン、モバイルパソコン、電子ブックプレーヤー、携帯電話、携帯ファックス、携帯コピー、携帯プリンター、ヘッドフォンステレオ、ビデオムービー、液晶テレビ、ハンディークリーナー、ポータブルＣＤ、ミニディスク、トランシーバー、電子手帳、電卓、メモリーカード、携帯テープレコーダー、ラジオ、モーター、照明器具、玩具、ゲーム機器、時計、ストロボ、カメラ、電動自転車、電動工具等の電源、バックアップ電源などが挙げられる。

<Applications of non-aqueous energy storage devices>
The application of the non-aqueous electrolyte storage element of the present embodiment is not particularly limited and can be used for various applications, such as a notebook computer, pen input personal computer, mobile personal computer, electronic book player, mobile phone, mobile fax, Portable copy, portable printer, headphone stereo, video movie, LCD TV, handy cleaner, portable CD, mini-disc, walkie-talkie, electronic notebook, calculator, memory card, portable tape recorder, radio, motor, lighting equipment, toy, game machine, Examples include power supplies for watches, strobes, cameras, electric bicycles, electric tools, backup power supplies, and the like.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

Example 1
<Preparation of positive electrode>
Porous carbon CNovel (manufactured by Toyo Tanso Co., Ltd.) (hereinafter referred to as porous carbon A) is used as the positive electrode active material, and powdery Denka black (acetylene black) (manufactured by Denka), binder BM as a conductive additive. -400B (polyvinylidene fluoride (PVDF)) (manufactured by ZEON Corporation) was mixed so that the mass ratio of the solid content was 100: 7.7: 9.5, and then N-methyl-2-pyrrolidone (NMP ) Was added to adjust to an appropriate viscosity to prepare a slurry for positive electrode material.

  The physical properties of porous carbon A are shown below.

Median diameter (D ₅₀ ) = 10.0 [μm]
BET specific surface area = 1618.4 [m ² / g]
Total pore volume = 1.5 [mL / g]
Mesopore content in pores = 44.3 [%]
Porous property = Yes Three-dimensional network structure = Yes Using a comma coater, a slurry for positive electrode material was applied to one side of an aluminum foil having an average thickness of 15 μm and then dried to form a positive electrode material. At this time, the basis weight of the porous carbon of the positive electrode material, that is, the average mass per unit area was 5.0 mg / cm ² . The aluminum foil on which the positive electrode material was formed was punched out to a diameter of 16 mm to produce a positive electrode.

<Separator>
Two sheets of glass filter paper GA100 (manufactured by ADVANTEC) punched to a diameter of 16 mm were stacked and used as a separator.

<Non-aqueous electrolyte>
After 2 mol / L LiBF ₄ is dissolved in a mixed solvent of ethylene carbonate (EC) / methyl ethyl carbonate (EMC) (mass ratio 1: 3) (manufactured by Ube Industries), the content becomes 10% by mass. As described above, an ionic liquid (manufactured by Piotrek) was added to prepare a non-aqueous electrolyte. At this time, the ionic liquid is composed of N-methyl-N-propylpyrrolidinium ion (MPPY) and bisfluorosulfonylimide ion (FSI).

<Production of negative electrode>
Graphite MAGD (manufactured by Hitachi Chemical Co., Ltd.) as the negative electrode active material, powdery Denka black (acetylene black) (manufactured by Denka Co., Ltd.), binder BM-400B (manufactured by Nippon Zeon Co., Ltd.) After mixing so that the mass ratio was 100: 3.0: 5.0, NMP was added to adjust to an appropriate viscosity to prepare a slurry for negative electrode material.

Using a comma coater, the negative electrode material slurry was applied to one side of a copper foil having an average thickness of 8 μm, and then dried to form a negative electrode material. At this time, the basis weight of graphite of the negative electrode material, that is, the average of the mass per unit area was 4.5 mg / cm ² . The copper foil on which the negative electrode material was formed was punched into a diameter of 16 mm to produce a negative electrode.

  After the negative electrode and separator were vacuum dried at 150 ° C. for 4 hours, a 2032 type coin cell was placed in a dry argon glove box together with a positive electrode obtained by punching out a 0.5 mm thick lithium metal foil (Honjo Metal Co., Ltd.) with a diameter of 16 mm. Assembled. Next, a 2032 type coin cell was filled with 400 μL of a non-aqueous electrolyte solution, thereby manufacturing a non-aqueous power storage element for producing a negative electrode.

  After short-circuiting the negative electrode and the positive electrode of the non-aqueous storage element for preparing the negative electrode for two days and inserting lithium ions into the negative electrode active material side, the non-aqueous storage element for preparing the negative electrode is disassembled, and the negative electrode into which the lithium ions have been inserted Produced.

<Preparation of non-aqueous storage element>
After the positive electrode and the separator were vacuum-dried at 150 ° C. for 4 hours, a 2032 type coin cell was assembled in a dry argon glove box together with the negative electrode into which lithium ions were inserted. Next, a 2032 type coin cell was filled with 400 μL of a non-aqueous electrolyte solution to produce a non-aqueous power storage element.

(Examples 2-9)
The content of the ionic liquid in the non-aqueous electrolyte is 0.9% by mass, 1.0% by mass, 2.9% by mass, 3.0% by mass, 15.0% by mass, 15.2% by mass, A non-aqueous electricity storage device was produced in the same manner as in Example 1 except that the content was changed to 18.0% by mass and 18.1% by mass.

(Example 10)
Except having used the ionic liquid (made by Piotrec) made from N, N-diethyl-N-methyl-methoxyethylammonium ion (DEME) and bisfluorosulfonylimide ion (FSI), in the same manner as in Example 1, A non-aqueous storage element was produced.

(Example 11)
Nonaqueous storage in the same manner as in Example 1 except that an ionic liquid (manufactured by Piotrec Co.) consisting of N-methyl-N-propylpyrrolidinium ion (MPPY) and bistrifluoromethanesulfonimide ion (TFSI) was used. An element was produced.

(Example 12)
A non-aqueous storage element was produced in the same manner as in Example 1 except that porous carbon CNovel (manufactured by Toyo Tanso Co., Ltd.) (hereinafter referred to as porous carbon B) was used as the positive electrode active material.

  The physical properties of porous carbon B are shown below.

Median diameter (D ₅₀ ) = 3.8 [μm]
BET specific surface area = 992.8 [m ² / g]
Total pore volume = 1.0 [mL / g]
Mesopore content in pores = 24.9 [%]
Porous property = Yes Three-dimensional network structure = Yes (Example 13)
A non-aqueous electricity storage device was produced in the same manner as in Example 1 except that porous carbon CNovel (manufactured by Toyo Tanso Co., Ltd.) (hereinafter referred to as porous carbon C) was used as the positive electrode active material.

  The physical properties of porous carbon C are shown below.

Median diameter (D ₅₀ ) = 3.6 [μm]
BET specific surface area = 992.2 [m ² / g]
Total pore volume = 1.0 [mL / g]
Mesopore content in pores = 25.0 [%]
Porous property = Yes Three-dimensional network structure = Yes (Example 14)
A non-aqueous electricity storage device was produced in the same manner as in Example 1 except that porous carbon CNovel (manufactured by Toyo Tanso Co., Ltd.) (hereinafter referred to as porous carbon D) was used as the positive electrode active material.

  The physical properties of porous carbon D are shown below.

Median diameter (D ₅₀ ) = 4.4 [μm]
BET specific surface area = 1190.1 [m ² / g]
Total pore volume = 1.2 [mL / g]
Mesopore content in pores = 29.9 [%]
Porous property = Yes Three-dimensional network structure = Yes (Example 15)
A non-aqueous storage element was produced in the same manner as in Example 1 except that porous carbon CNovel (manufactured by Toyo Tanso Co., Ltd.) (hereinafter referred to as porous carbon E) was used as the positive electrode active material.

  The physical properties of porous carbon E are shown below.

Median diameter (D ₅₀ ) = 4.7 [μm]
BET specific surface area = 1193.4 [m ² / g]
Total pore volume = 1.2 [mL / g]
Mesopore content in pores = 30.0 [%]
Porous property = Yes Three-dimensional network structure = Yes (Example 16)
A non-aqueous storage element was produced in the same manner as in Example 1 except that porous carbon CNovel (manufactured by Toyo Tanso Co., Ltd.) (hereinafter referred to as porous carbon F) was used as the positive electrode active material.

  The physical properties of the porous carbon F are shown below.

Median diameter (D ₅₀ ) = 10.0 [μm]
BET specific surface area = 74.2 [m ² / g]
Total pore volume = 0.4 [mL / g]
Mesopore content in pores = 60.0 [%]
Porous property = Yes Three-dimensional network structure = Yes (Example 17)
A non-aqueous electricity storage device was produced in the same manner as in Example 1 except that porous carbon CNovel (manufactured by Toyo Tanso Co., Ltd.) (hereinafter referred to as porous carbon G) was used as the positive electrode active material.

  The physical properties of the porous carbon G are shown below.

Median diameter (D ₅₀ ) = 10.0 [μm]
BET specific surface area = 69.1 [m ² / g]
Total pore volume = 0.4 [mL / g]
Mesopore content in pores = 60.2 [%]
Porous property = Yes Three-dimensional network structure = Yes (Example 18)
A non-aqueous electricity storage device was produced in the same manner as in Example 1 except that porous carbon CNovel (manufactured by Toyo Tanso Co., Ltd.) (hereinafter referred to as porous carbon H) was used as the positive electrode active material.

  The physical properties of the porous carbon H are shown below.

Median diameter (D ₅₀ ) = 10.3 [μm]
BET specific surface area = 49.1 [m ² / g]
Total pore volume = 0.4 [mL / g]
Mesopore content in the pores = 80.0 [%]
Porous property = Yes Three-dimensional network structure = Yes (Example 19)
A non-aqueous electricity storage device was produced in the same manner as in Example 1 except that porous carbon CNovel (manufactured by Toyo Tanso Co., Ltd.) (hereinafter referred to as porous carbon I) was used as the positive electrode active material.

  The physical properties of porous carbon I are shown below.

Median diameter (D ₅₀ ) = 10.0 [μm]
BET specific surface area = 48.7 [m ² / g]
Total pore volume = 0.4 [mL / g]
Mesopore content in pores = 80.2 [%]
Porous property = Yes Three-dimensional network structure = Yes (Example 20)
<Production of negative electrode>
Lithium titanate (Li ₄ Ti ₅ O ₁₂ ) (made by Titanium Industry Co., Ltd.) (hereinafter referred to as LTO) as a negative electrode active material, powdered Denka black (acetylene black) (made by Denka Co.) as a conductive additive After mixing acrylate latex TRD202A (manufactured by JSR) and Daicel 2200 (carboxymethylcellulose) (manufactured by Daicel Chemical Industries) as a binder so that the mass ratio of the solid content is 100: 7: 3: 1. Then, water was added to adjust to an appropriate viscosity to prepare a slurry for negative electrode material.

The negative electrode material slurry was applied to one side of an aluminum foil having an average thickness of 15 μm using a bar coater and then dried to form a negative electrode material. At this time, the basis weight of LTO of the negative electrode material, that is, the average of the mass per unit area was 3.0 mg / cm ² . The aluminum foil on which the negative electrode material was formed was punched out to a diameter of 16 mm to produce a negative electrode.

  A non-aqueous storage element was produced in the same manner as in Example 1 except that the above negative electrode was used.

(Comparative Example 1)
A non-aqueous storage element was produced in the same manner as in Example 1 except that no ionic liquid was added.

(Comparative Example 2)
A nonaqueous storage element in the same manner as in Example 1 except that lithium cobalt oxide (manufactured by Nichia Chemical Co., Ltd.) (hereinafter referred to as LCO) was used as the positive electrode active material, and a negative electrode into which lithium ions were not inserted was used. Was made.

(Comparative Example 3)
A non-aqueous electricity storage device was produced in the same manner as in Example 1 except that artificial graphite KS-6 (manufactured by TIMCAL) was used as the positive electrode active material.

  The physical properties of artificial graphite are shown below.

Median diameter (D ₅₀ ) = 10.0 [μm]
BET specific surface area = 17.6 [m ² / g]
Mesopore content in pores = 82.0 [%]
Porous property = None Three-dimensional network structure = None (Comparative Example 4)
A non-aqueous storage element was produced in the same manner as in Example 1 except that activated carbon bell fine (manufactured by AT Electrode Co.) was used as the positive electrode active material.

  The physical properties of activated carbon are shown below.

Median diameter (D ₅₀ ) = 10.7 [μm]
BET specific surface area = 1360.0 [m ² / g]
Total pore volume = 1.1 [mL / g]
Mesopore content in pores = 4.7 [%]
Porousness = Existence Three-dimensional network structure = None Below, the formation state of carbon pores used as the positive electrode active material (porosity, three-dimensional network structure), BET specific surface area, mesopore content, total fineness The evaluation method of pore volume and median diameter (D ₅₀ ) is described.

<Porosity formation state (porosity, three-dimensional network structure)>
With a transmission electron microscope JEM-2100 (manufactured by JEOL Ltd.), the presence or absence of porosity and a three-dimensional network structure was observed.

<BET specific surface area and total pore volume>
The adsorption isotherm was measured by an automatic specific surface area / pore distribution measuring device TriStar II 3020 (manufactured by Shimadzu Corporation), and then the BET specific surface area was determined by the BET (Brunauer, Emmett, Teller) method. The total pore volume was determined from the adsorption isotherm by the BJH (Barrett, Joyner, Hallender) method.

<Mesopore content>
The adsorption isotherm (see FIG. 1) was measured by an automatic specific surface area / pore distribution measuring device TriStar II 3020 (manufactured by Shimadzu Corporation), and then the content of mesopores in the pores was determined by equation (1).

<Median diameter _(D 50)>
The median diameter (D ₅₀ ) was measured with a laser diffraction / scattering particle size distribution measuring apparatus LA-950 (manufactured by Horiba, Ltd.).

  Table 1 shows the physical properties of carbon used as the positive electrode active material.

表２に、非水系蓄電素子の構成を示す。

Table 2 shows the configuration of the non-aqueous power storage element.

次に、非水系蓄電素子の放電容量及び放電レート特性を評価した。

Next, the discharge capacity and discharge rate characteristics of the non-aqueous storage element were evaluated.

<Discharge capacity and discharge rate characteristics>
A charge / discharge test was conducted under the conditions shown in Table 3 using an automatic battery evaluation device 1024B-7V0.1A-4 (manufactured by Electrofield) with a non-aqueous storage element held in a thermostat at 25 ° C. Then, the discharge capacity and discharge rate characteristics of the non-aqueous storage element were evaluated.

なお、ＣＣは、定電流を意味する。

CC means a constant current.

  Specifically, first, the reference current value is set to 2.0 mA (1 C), and the battery is charged to the end-of-charge voltage of 4.4 V at a current value (0.2 C) that is 1/5 of the reference current value. The battery was discharged to a discharge end voltage of 1.8V. At this time, a pause of 120 minutes was made after charging, and a 5-minute rest after discharging.

  Next, after charging to the end-of-charge voltage of 4.4V at the reference current value (1C), the charge / discharge cycle of discharging to the end-of-discharge voltage of 1.8V at 1C is repeated 5 times, and the fifth discharge capacity is defined as 1C discharge capacity. did. At this time, a pause of 5 minutes was put between charge and discharge.

  Furthermore, after charging to a final charge voltage of 4.4V at a current value (50C) 50 times the reference current value, the charge / discharge cycle of discharging at 50C to a final discharge voltage of 1.8V is repeated five times, and the fifth discharge capacity. Was set to a 50C discharge capacity. At this time, a pause of 5 minutes was put between charge and discharge.

  In FIG. 4, the measurement result of the discharge capacity of the nonaqueous storage element of Example 1 and Comparative Example 1 is shown.

  When evaluating the discharge capacity and discharge rate characteristics of the non-aqueous storage element of Example 20, the end-of-charge voltage was 2.9 V and the end-of-discharge voltage was 0.8 V.

  Moreover, when evaluating the discharge capacity and discharge rate characteristics of the non-aqueous storage element of Comparative Example 2, the charge end voltage was 4.2 V, and the discharge end voltage was 3.0 V.

Next, the formula (50C discharge capacity) / (1C discharge capacity) × 100
Thus, the discharge rate characteristics of the non-aqueous storage element were derived.

  Table 4 shows the evaluation results of the discharge capacity and discharge rate characteristics of the non-aqueous storage element.

表４の結果から、実施例１〜２０の非水系蓄電素子は、１Ｃ放電容量が高く、放電レート特性に優れることがわかる。

From the results of Table 4, it can be seen that the non-aqueous energy storage devices of Examples 1 to 20 have a high 1C discharge capacity and excellent discharge rate characteristics.

  On the other hand, since the non-aqueous electricity storage device of Comparative Example 1 does not contain an ionic liquid in the non-aqueous electrolyte, the discharge rate characteristics are degraded.

  Moreover, since the non-aqueous storage element of Comparative Example 2 uses lithium cobaltate having a high resistance value as the positive electrode active material, the 50C discharge capacity is reduced and the discharge rate characteristics are reduced.

  Moreover, since the nonaqueous electrical storage element of the comparative example 3 uses artificial graphite with a small BET specific surface area as a positive electrode active material, 1C discharge capacity and 50C discharge capacity fall.

  Further, since the non-aqueous energy storage device of Comparative Example 4 uses activated carbon that does not have a three-dimensional network structure as the positive electrode active material, the non-aqueous electrolyte sufficiently penetrates into the pores during high-speed charge / discharge. The discharge rate characteristic is deteriorated.

  As described above, the non-aqueous storage element of this example uses porous carbon in which pores having a three-dimensional network structure are formed, and the ionic liquid is included in the non-aqueous electrolyte, so that the discharge capacity is high. Excellent discharge rate characteristics.

DESCRIPTION OF SYMBOLS 10 Nonaqueous storage element 11 Positive electrode 11a Positive electrode collector 11b Porous carbon 11c Binder 11d Conductive auxiliary agent 12 Negative electrode 12a Negative electrode collector 12b Carbon 12c Binder 12d Conductive auxiliary agent 13 Separator 14 Exterior cans 15 and 16 Lead line N Nonaqueous Electrolyte A Anion C Cation

JP-A-2005-251472 JP 2012-142340 A

Claims (7)

A positive electrode containing a positive electrode active material capable of inserting or releasing anions;
A negative electrode containing a negative electrode active material;
Having a non-aqueous electrolyte,
The positive electrode active material is porous carbon in which pores having a three-dimensional network structure are formed,
The nonaqueous electrolytic solution includes a nonaqueous solvent, an electrolyte salt, and an ionic liquid. ^2. The non-aqueous system according to claim 1, wherein the porous carbon has a BET specific surface area of 50 m ² / g or more and a total pore volume of 0.2 mL / g or more and 2.3 mL / g or less. Power storage element.   The non-aqueous storage element according to claim 1, wherein the pore includes a mesopore having a pore diameter of 2 nm to 50 nm.   4. The non-aqueous storage element according to claim 3, wherein the pores have a mesopore content of 25% or more and 80% or less. 5.   5. The ionic liquid according to claim 1, wherein the ionic liquid contains N, N-diethyl-N-methyl-N-methoxyethylammonium ion and / or N-methyl-N-propylpyrrolidinium ion. The nonaqueous electrical storage element of description.   The non-aqueous storage element according to claim 1, wherein the ionic liquid contains bisfluorosulfonylimide ion and / or bistrifluoromethanesulfonimide ion.   7. The non-aqueous storage element according to claim 1, wherein the non-aqueous electrolyte has a content of the ionic liquid of 1% by mass or more and 18% by mass or less.

Images