Ion conductor, composite, sheet, electrode, separator, and electricity storage device

Abstract

Provided are an ion conductor, a composite, a sheet, an electrode, a separator, and an electricity storage device with which lithium ion conductivity can be controlled. The ion conductor (10) contains a solid electrolyte (19) having a garnet-type crystal structure containing Li, La, Zr, and O, and lithium carbonate (19a) is locally present on the surface of the solid electrolyte. The composite (19d) contains an ion conductor and an ionic liquid in which a lithium salt is dissolved, the ionic liquid contains fluorine anions, and the relative concentration ratio of fluoride to carbonate ions in the membrane (19c) covering the surface of the solid electrolyte is 0.1 or more. The electricity storage device (11) includes an ion conductor.

Description

Technical Field

[0001] The present invention relates to an ion conductor, a composite, a sheet, an electrode, a separator, and an electricity storage device containing a solid electrolyte. Background Art

[0002] A solid electrolyte containing Li, La, Zr, and O and having a garnet-type crystal structure reacts with moisture and carbon dioxide in the atmosphere to generate lithium carbonate on the surface (Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 6735425 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] The lithium ion conductivity of lithium carbonate is significantly lower than that of solid electrolytes with a garnet crystal structure, so the lithium carbonate on the surface of the solid electrolyte becomes a resistive phase. Therefore, in order to control the lithium ion conductivity of an ion conductor including a solid electrolyte, it is necessary to control the surface state of the solid electrolyte.

[0008] The present invention has been made to meet this demand, and an object of the present invention is to provide an ion conductor, a composite, a sheet, and a power storage device capable of controlling lithium ion conductivity.

[0009] Methods used to solve problems

[0010] A first means for achieving this object is an ion conductor comprising a solid electrolyte having a garnet-type crystal structure containing Li, La, Zr, and O, wherein lithium carbonate is locally present on the surface of the solid electrolyte.

[0011] A second aspect is that, in the first aspect, a relative concentration ratio of zirconium to carbonate ions on the surface of the solid electrolyte is 0.01 or more.

[0012] The third embodiment is a composite comprising the ion conductor of the first or second embodiment and an ionic liquid in which a lithium salt is dissolved, wherein the ionic liquid contains fluoride anions and has a film covering the surface of the solid electrolyte, wherein the relative concentration ratio of fluoride to carbonate ions in the film is 0.1 or more.

[0013] A fourth embodiment is that, in the third embodiment, the solid electrolyte further contains Mg and Sr, and does not contain F.

[0014] A fifth aspect is a sheet including the ion conductor according to the first or second aspect, or the composite according to the third or fourth aspect.

[0015] A sixth embodiment is an electrode comprising the ion conductor of the first or second embodiment, or the composite of the third or fourth embodiment. Alternatively, the electrode is in contact with a protective layer comprising the ion conductor of the first or second embodiment, or the composite of the third or fourth embodiment.

[0016] A seventh aspect is a separator comprising the ion conductor of the first or second aspect, or the composite of the third or fourth aspect. Alternatively, the separator is in contact with a protective layer comprising the ion conductor of the first or second aspect, or the composite of the third or fourth aspect.

[0017] An eighth aspect is an electricity storage device including the electrode according to the sixth aspect or the separator according to the seventh aspect.

[0018] Effects of the Invention

[0019] The solid electrolyte having a garnet-type crystal structure containing Li, La, Zr, and O contained in the ion conductor, composite, sheet, electrode, separator, and energy storage device of the present invention has lithium carbonate as a resistive phase only locally present on its surface, thereby enabling control of lithium ion conductivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a cross-sectional view of the electricity storage device including the ion conductor in the first embodiment.

[0021] Figure 2 is a diagram schematically showing a garnet-type crystal structure.

[0022] Figure 3 (a) is a cross-sectional view of a solid electrolyte, and (b) is a cross-sectional view of a solid electrolyte in contact with an ionic liquid.

[0023] Figure 4 It is a cross-sectional view of the power storage device in the second embodiment.

[0024] Figure 5 It is a cross-sectional view of the power storage device in the third embodiment.

[0025] Figure 6 (a) is a cross-sectional view of an insulator in a fourth embodiment, (b) is a cross-sectional view of an electrode in a fifth embodiment, and (c) is a cross-sectional view of an electrode in a sixth embodiment. DETAILED DESCRIPTION

[0026] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Figure 1This is a schematic cross-sectional view of an electrical storage device 11 including an ion conductor 10 in the first embodiment. Electrical storage device 11 in this embodiment is a lithium-ion solid-state battery in which the power generation element is composed of a solid. "Composition of the power generation element as a solid" means that the skeleton of the power generation element is composed of a solid, including embodiments in which the skeleton is impregnated with a liquid.

[0027] The electricity storage device 11 includes, in order, a positive electrode layer 12, a separator 15, and a negative electrode layer 16. The positive electrode layer 12, the separator 15, and the negative electrode layer 16 are housed in a case (not shown).

[0028] The positive electrode layer 12 is stacked with a current collecting layer 13 and an active material layer 14. The current collecting layer 13 is a conductive member. Examples of materials for the current collecting layer 13 include metals selected from Ni, Ti, Fe, and Al, alloys containing two or more of these elements, stainless steel, and carbon materials.

[0029] Active material layer 14 includes ion conductor 10 and active material 20. Ion conductor 10 includes solid electrolyte 19. To reduce the resistance of active material layer 14, a conductive additive may be included in active material layer 14. Examples of the conductive additive include carbon black, acetylene black, Ketjen black, carbon fiber, Ni, Pt, and Ag.

[0030] Examples of the active material 20 include metal oxides containing transition metals, sulfur-based active materials, and organic active materials. Examples of the metal oxide containing transition metals include metal oxides containing one or more elements selected from Mn, Co, Ni, Fe, Cr, and V, and Li. Examples of the metal oxide containing transition metals include LiCoO2, LiNi 0.8 Co 0.15 Al 0.05 O2、LiMn2O4、LiNiVO4、LiNi 0.5 Mn 1.5 O4、LiNi 1 / 3 Mn 1 / 3 Co 1 / 3 O4 and LiFePO4.

[0031] In order to suppress the reaction between the active material 20 and the solid electrolyte 19, a coating layer may be provided on the surface of the active material 20. Examples of the coating layer include Al2O3, ZrO2, LiNbO3, Li4Ti5O 12 , LiTaO3, LiNbO3, LiAlO2, Li2ZrO3, Li2WO4, Li2TiO3, Li2B4O7, Li3PO4 and Li2MoO4.

[0032] Examples of sulfur-based active materials include S, TiS2, NiS, FeS2, Li2S, MoS3, and sulfur-carbon composite materials. Examples of organic active materials include free radical compounds represented by 2,2,6,6-tetramethylpiperidinyloxy-4-yl methacrylate and polytetramethylpiperidinyloxyvinyl ether, quinone compounds, radialene compounds, tetracyanoquinodimethane, and phenazine oxide.

[0033] The separator 15 separates the positive electrode layer 12 and the negative electrode layer 16 to electrically insulate them from each other. The separator 15 is composed of an ion conductor 10. The ion conductor 10 includes a solid electrolyte 19 and an electrolyte solution. The ion conductor 10 may further include a binder.

[0034] The negative electrode layer 16 is stacked with a current collecting layer 17 and an active material layer 18. The current collecting layer 17 is a conductive member. Examples of materials for the current collecting layer 17 include metals selected from Ni, Ti, Fe, Cu, and Si, alloys containing two or more of these elements, stainless steel, and carbon materials.

[0035] The active material layer 18 includes an ion conductor 10 and an active material 21. In order to reduce the resistance of the active material layer 18, a conductive additive may be included in the active material layer 18. Examples of conductive additives include carbon black, acetylene black, Ketjen black, carbon fiber, Ni, Pt, and Ag. Examples of active material 21 include Li, Li-Al alloy, Li4Ti5O 12 , graphite, In, Si, Si—Li alloy, and SiO. Similar to the separator 15 , the active material layers 14 and 18 may contain a binder.

[0036] The energy storage device 11 is manufactured, for example, as follows. A slurry is prepared by mixing a solution obtained by dissolving a binder in a solvent with a mixture of an ionic liquid (electrolyte) containing a lithium salt and a solid electrolyte 19. The slurry is formed into a sheet and then dried to obtain a green sheet (electrolyte sheet) for the separator 15.

[0037] An active material 20 is mixed with a mixture of an ionic liquid (electrolyte) containing a lithium salt and a solid electrolyte 19, and a solution of a binder dissolved in a solvent is further mixed to prepare a slurry. The slurry is applied to the current collector layer 13 and then dried to obtain a green sheet (positive electrode sheet) for the positive electrode layer 12.

[0038] The active material 21 is mixed with a mixture of an ionic liquid (electrolyte) containing a lithium salt and a solid electrolyte 19, and then mixed with a solution of a binder dissolved in a solvent to prepare a slurry. The slurry is applied to the current collector layer 17 and then dried to obtain a green sheet (negative electrode sheet) for the negative electrode layer 16.

[0039] After the electrolyte sheet, positive electrode sheet, and negative electrode sheet are cut into predetermined shapes, they are stacked in the order of positive electrode sheet, electrolyte sheet, and negative electrode sheet, and crimped together to form an integrated structure. Terminals (not shown) are connected to the collector layers 13 and 17, respectively, and the assembly is sealed in a housing (not shown), resulting in a storage device 11 comprising a positive electrode layer 12, a separator 15, and a negative electrode layer 16. In this way, the sheet containing the solid electrolyte 19 can be mixed to form an electrolyte sheet, a positive electrode sheet, and a negative electrode sheet.

[0040] The solid electrolyte 19 is a composite oxide containing Li, La and Zr and having a garnet-type crystal structure. This garnet-type crystal structure is represented by the general formula C3A2B3O 12 express.

[0041] Figure 2 : is a diagram schematically showing a garnet-type crystal structure. In the garnet-type crystal structure, the C site Sc is dodecahedrally coordinated with the oxygen atom Oa, the A site Sa is octahedrally coordinated with the oxygen atom Oa, and the B site Sb is tetrahedrally coordinated with the oxygen atom Oa. In the conventional garnet-type crystal structure of the solid electrolyte 19, Li may be present in the site that is octahedrally coordinated with the oxygen atom Oa and becomes the void V. The void V is, for example, a site sandwiched between the B site Sb1 and the B site Sb2. The Li present in the void V is octahedrally coordinated with the oxygen atom Oa constituting the octahedron containing the face Fb1 of the tetrahedron forming the B site Sb1 and the face Fb2 of the tetrahedron forming the B site Sb2. For example, Li7La3Zr2O having a garnet-type crystal structure 12 In the structure, La can occupy the C site Sc, Zr can occupy the A site Sa, and Li can occupy the B site Sb and the void V.

[0042] The garnet crystal structure has the same X-ray diffraction pattern as that of CSD (Cambridge Structural Database) file No. 422259 (Li7La3Zr2O 12 ). Solid electrolyte 19 may differ from No. 422259 in terms of the types of constituent elements and lithium concentration, resulting in different diffraction angles and intensity ratios. Its representative crystal structure is cubic (space group Ia-3d (- indicates an overline indicating a rotation-inversion operation), JCPDS: 84-1753).

[0043] return Figure 1 The solid electrolyte 19 is typically Li7La3Zr2O 12The constituent elements of the solid electrolyte 19 may be partially replaced by other elements, or a trace amount of other elements may be added without replacing the constituent elements. Examples of the other elements include at least one element selected from the group consisting of Mg, Al, Si, Ca, Ti, V, Ga, Sr, Y, Nb, Sn, Sb, Ba, Hf, Ta, W, Bi, Rb, and lanthanoid elements (excluding La).

[0044] The solid electrolyte 19 can be, for example, Li6La3Zr 1.5 W 0.5 O 12 、Li 6.15 La3Zr 1.75 Ta 0.25 Al 0.2 O 12 、Li 6.15 La3Zr 1.75 Ta 0.25 Ga 0.2 O 12 、Li 6.25 La3Zr2Ga 0.25 O 12 、Li 6.4 La3Zr 1.4 Ta 0.6 O 12 、Li 6.5 La3Zr 1.75 Te 0.25 O 12 、Li 6.75 La3Zr 1.75 Nb 0.25 O 12 、Li 6.9 La3Zr 1.675 Ta 0.289 Bi 0.036 O 12 、Li 6.46 Ga 0.23 La3Zr 1.85 Y 0.15 O 12 、Li 6.8 La 2.95 Ca 0.05 Zr 1.75 Nb 0.25 O 12 、Li 7.05 La 3.00 Zr 1.95 Gd 0.05 O 12 、Li 6.20 Ba 0.30 La 2.95 Rb 0.05 Zr2O12 .

[0045] Solid electrolyte 19 is particularly preferably a solid electrolyte containing at least one of Mg and element A (A is at least one element selected from the group consisting of Ca, Sr, and Ba), with the molar ratio of each element satisfying all of the following (1) to (3); or a solid electrolyte containing both Mg and element A, with the molar ratio of each element satisfying all of the following (4) to (6). To improve the ionic conductivity of solid electrolyte 19, element A is preferably Sr.

[0046] (1)1.33≤Li / (La+A)≤3

[0047] (2)0≤Mg / (La+A)≤0.5

[0048] (3)0≤A / (La+A)≤0.67

[0049] (4)2.0≤Li / (La+A)≤2.6

[0050] (5)0.01≤Mg / (La+A)≤0.14

[0051] (6)0.04≤A / (La+A)≤0.17

[0052] The median diameter of the equivalent circle diameter of the solid electrolyte 19 appearing in the cross section of the separator 15 is preferably 0.5-10 μm, more preferably 0.5-6 μm. This is to ensure that the surface area of ​​the solid electrolyte 19 is appropriately large and that the amount of Li ions that can move between the electrolyte solution present on the surface of the solid electrolyte 19 and the solid electrolyte 19 is ensured.

[0053] In order to determine the median particle size of the solid electrolyte 19, first analyze the scanning electron microscope (SEM) image of the solid electrolyte 19 appearing in the cross section of the diaphragm 15 (the polished surface, the surface obtained by irradiation with a focused ion beam (FIB), and the surface obtained by ion milling), calculate the equivalent circle diameter based on the area of ​​each particle of the solid electrolyte 19, and calculate the volume-based particle size distribution. The median particle size is the equivalent circle diameter at which the cumulative value of the frequency in the particle size distribution is 50%. In order to ensure accuracy, the image for determining the particle size distribution is set to 400 μm in the diaphragm 15. 2 The area above.

[0054] The ion conductor 10 may contain one or more other solid electrolytes in addition to the solid electrolyte 19 having a garnet-type crystal structure containing Li, La, Zr, and O. Other solid electrolytes include crystalline or amorphous oxide-based solid electrolytes such as perovskite-type, NASICON-type, and LISICON-type, and hydride-based solid electrolytes.

[0055] Perovskite-type solid electrolytes include oxides containing at least Li, Ti, and La, such as La 2 / 3- X Li 3X TiO3. NASICON type solid electrolytes include oxides containing at least Li, M (M is one or more elements selected from Ti, Zr and Ge) and P, such as Li(Al,Ti)2(PO4)3 and Li(Al,Ge)2(PO4)3. LISICON type solid electrolytes include Li 14 Zn(GeO4)4. Hydride-based solid electrolytes are hydrides of alkali metals or alkaline earth metals, and examples thereof include hydrides containing at least one of the Group 13 elements of the Group 18 periodic table (e.g., B, Al, Ga, In, Ta). Examples include LiBH4 and LiAlH4.

[0056] The ion conductor 10 includes an ionic liquid in which a lithium salt is dissolved. The lithium salt is a compound used for the transfer of cations between the positive electrode layer 12 and the negative electrode layer 16. Examples of anions of the lithium salt include halide ions (I - 、Cl - Br - etc.), SCN - 、BF4 - 、BF3(CF3) - 、BF3(C2F5) - PF6 - 、ClO4 - 、SbF6 - 、N(SO2F)2 - 、N(SO2CF3)2 - 、N(SO2C2F5)2 - 、B(C6H5)4 - 、B(O2C2H4)2 - 、C(SO2F)3 - 、C(SO2CF3)3 - CF3COO - CF3SO2O - 、C6F5SO2O - 、B(O2C2O2)2 - RCOO - (R is an alkyl group having 1 to 4 carbon atoms, a phenyl group or a naphthyl group), etc.

[0057] The anion of the lithium salt is preferably N(SO2F)2 having a sulfonyl group -S(=O)2- - 、N(SO2CF3)2 - 、N(SO2C2F5)2- This is because, for sulfonyl imide anions, even if the salt concentration increases, the effect of increased electrolyte viscosity and decreased ion conductivity is minimal, and further, by forming a highly stable and low-resistance film (SEI), it can reduce the reductive decomposition of the ionic liquid and expand the reduction-side potential window.

[0058] Sometimes N(SO2F)2 - Abbreviated as [FSI] - :bis(fluorosulfonyl)imide anion, N(SO2CF3)2 - Abbreviated as [TFSI] - : Bis(trifluoromethanesulfonyl)imide anion. Lithium bis(fluorosulfonyl)imide (LiFSI) is particularly preferred as the lithium salt. This is because LiFSI is less affected by the viscosity increase of the ionic liquid and is effective in forming a good passivation coating (SEI).

[0059] Ionic liquids are compounds composed of cations and anions that are liquid at room temperature and pressure. Ionic liquids have a relatively wide potential window and high flame retardancy, so they are preferred. Ionic liquids are preferably selected from ammonium, imidazole, , pyrrolidine and piperidine One or more of the above can be used as cationic species.

[0060] The anion component of the ionic liquid is not particularly limited. Examples of the anion component include BF4 - 、N(SO2F)2 - Inorganic anions such as B(C6H5)4 - 、CH3SO3 - CF3SO3 - 、N(SO2CF3)2 - 、N(SO2C4F9)2 - As the anion component of the ionic liquid, fluorine-based anions containing fluorine atoms are preferred due to their high reactivity.

[0061] Examples of ionic liquids include N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium bis(fluorosulfonyl)imide (DEME-FSI), N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium bis(trifluoromethanesulfonyl)imide (DEME-TFSI), 1-ethyl-3-methylimidazole Bis(fluorosulfonyl)imide (EMI-FSI), 1-ethyl-3-methylimidazole Bis(trifluoromethanesulfonyl)imide (EMI-TFSI), N-butyl-N-methylpiperidine Bis(fluorosulfonyl)imide, N-methyl-N-propylpiperidine Bis(trifluoromethanesulfonyl)imide, N-methyl-N-propylpyrrolidine Bis(fluorosulfonyl)imide (P13FSI), N-methyl-N-propylpyrrolidine Bis(trifluoromethanesulfonyl)imide (P13TFSI). It can also be a mixture thereof.

[0062] The ionic liquid may be a solvated ionic liquid. Examples of the solvated ionic liquid include a solution obtained by dissolving a lithium salt in a sulfone-based solvent such as sulfolane or a sulfolane derivative, or a glyme-based solvent such as tetraglyme.

[0063] Figure 3 (a) is a cross-sectional view of solid electrolyte 19. Lithium carbonate 19a is locally provided on the surface of solid electrolyte 19. Lithium carbonate 19a is a compound formed on the surface of solid electrolyte 19 by reacting with moisture and carbon dioxide in the atmosphere. By managing the moisture and carbon dioxide levels in the atmosphere surrounding the synthesized solid electrolyte 19, the time from synthesis of solid electrolyte 19 to processing, and other factors, lithium carbonate 19a can be locally provided on the surface of solid electrolyte 19.

[0064] The fact that lithium carbonate 19a is locally disposed on the surface of solid electrolyte 19 is evident from the observation of a spectrum corresponding to zirconium constituting solid electrolyte 19 and a spectrum corresponding to carbonate ions constituting lithium carbonate 19a when analyzing the surface of solid electrolyte 19 using X-ray photoelectron spectroscopy (XPS). Since lithium carbonate 19a, which forms a resistive phase, is only locally present on the surface of solid electrolyte 19, a portion can be provided in the ion conductor 10 of the assembly including solid electrolyte 19 where lithium carbonate 19a, which forms a resistive phase, is absent between solid electrolytes 19. Consequently, the lithium ion conductivity of ion conductor 10 can be controlled.

[0065] The zirconium on the surface of solid electrolyte 19 is preferably 0.01 or more and less than 1.00 relative to the relative concentration ratio of carbonate ions. This is because, if the zirconium is less than 0.01 relative to the relative concentration ratio of carbonate ions, the surface of solid electrolyte 19 is extensively covered by lithium carbonate, which is unfavorable for reducing the interface resistance of solid electrolyte 19. About the relative concentration ratio of zirconium relative to carbonate ions, the area intensity of the peak of the spectrum of XPS is calculated respectively, and concentration (atm%) is calculated by the relative sensitivity factor method using the intrinsic sensitivity coefficient of the device, obtained by its ratio.

[0066] Figure 3(b) is a cross-sectional view of a solid electrolyte 19 in contact with an ionic liquid containing fluorine anions. Lithium carbonate 19a is almost insoluble in the ionic liquid, so lithium carbonate 19a remains on the surface of the solid electrolyte 19 in contact with the ionic liquid. Lithium carbonate 19a does not react with the ionic liquid, but the solid electrolyte 19 reacts with the ionic liquid. The highly reactive fluorine anions react with the solid electrolyte 19, and a compound 19b containing a fluoride (a compound composed of fluorine and other elements or atomic groups) is generated in the portion of the solid electrolyte 19 that is not covered by lithium carbonate 19a. As a result, a film 19c containing lithium carbonate 19a and compound 19b is provided on the surface of the solid electrolyte 19. The complex 19d includes a solid electrolyte 19 provided with a film 19c containing lithium carbonate 19a and compound 19b.

[0067] The presence of fluoride chemically bonded to solid electrolyte 19 in compound 19b can be confirmed by XPS analysis. The chemical shift of the XPS peak position (binding energy value), which varies depending on the chemical bonding state, indicates that compound 19b is chemically bonded (chemically adsorbed) to the surface of solid electrolyte 19. The spectrum of fluoride chemically bonded to solid electrolyte 19 appears at 685 eV (F1s). The thickness of film 19c is estimated to be approximately 5 nm based on the XPS detection depth.

[0068] By heat-treating the solid electrolyte 19 in which compound 19b has been generated, a film 19c containing compound 19b can be fixed to the surface of the solid electrolyte 19. The heat treatment temperature can range from 60 to 90°C, and the heat treatment time can range from 1 to 3 hours. In the ion conductor 10 comprising the assembly of solid electrolytes 19 formed with a film 19c containing compound 19b, a portion containing compound 19b is formed between the solid electrolytes 19. Compound 19b has higher lithium ion conductivity than lithium carbonate 19a, and thus can improve lithium ion conductivity compared to a case where lithium carbonate is present between the solid electrolytes 19a and 19b. Therefore, the lithium ion conductivity of the ion conductor 10 can be controlled.

[0069] The fluoride of film 19c is preferably more than 0.1 and less than 1.0 relative to the relative concentration ratio of carbonate ion. This is because, if the relative concentration ratio of fluoride relative to carbonate ion is less than 0.01, the surface of solid electrolyte 19 is widely covered by lithium carbonate, which is unfavorable for reducing the interface resistance of solid electrolyte 19. The relative concentration ratio of fluoride relative to carbonate ion is obtained as follows: the area intensity of the peak of the spectrum of XPS is calculated respectively, concentration (atm%) is calculated by the relative sensitivity factor method using the intrinsic sensitivity coefficient of the device, and is obtained by the ratio.

[0070] The salt concentration of the ionic liquid in which the lithium salt is dissolved is preferably 4.0 mol / kg or less. This is because if the salt concentration of the ionic liquid exceeds 4.0 mol / kg, the lithium ion conductivity tends to decrease significantly due to the increase in the viscosity of the ionic liquid.

[0071] In the ion conductor 10, the ratio of the volume of the solid electrolyte 19 to the total volume of the solid electrolyte 19 and the ionic liquid is preferably 52% or more and less than 100%, and more preferably 61% or more and less than 100%. The combination of the solid electrolyte 19 and the ionic liquid reduces the interface resistance of the solid electrolyte 19, thereby increasing the transference number of Li ions in the ion conductor 10 compared to that of a typical electrolyte solution. As a result, the operational stability of the energy storage device 11 equipped with the ion conductor 10 is enhanced.

[0072] The ion conductor 10 may also contain a binder for binding the solid electrolyte 19. Examples of the binder include fluorinated resins, polyolefins, polyimides, polyvinyl pyrrolidone, polyvinyl alcohol, cellulose ethers, and rubbery polymers such as styrene butadiene rubber. Examples of the fluorinated resin include vinylidene fluoride polymers, polychlorotrifluoroethylene, polyvinyl fluoride, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers, tetrafluoroethylene-hexafluoropropylene copolymers, ethylene-tetrafluoroethylene copolymers, and ethylene-chlorotrifluoroethylene copolymers.

[0073] Examples of vinylidene fluoride polymers include homopolymers of vinylidene fluoride and copolymers of vinylidene fluoride and copolymerizable monomers. Copolymerizable monomers include halogen-containing monomers (excluding vinylidene fluoride) and non-halogen copolymerizable monomers. Examples of halogen-containing monomers include: chlorine-containing monomers such as vinyl chloride; fluorine-containing monomers such as trifluoroethylene, tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropylene, and perfluoroalkyl vinyl ether. Examples of non-halogen copolymerizable monomers include: olefins such as ethylene and propylene; acrylic monomers such as acrylic acid, methacrylic acid, and their esters or salts; vinyl monomers such as acrylonitrile, vinyl acetate, and styrene. One or more of the copolymerizable monomers are polymerized with vinylidene fluoride to form a copolymer.

[0074] The salt concentration of the ionic liquid contained in the ion conductor 10 is determined, for example, as follows: Here, the ion conductor 10 constituting the separator 15 is described, but the salt concentration of the ion conductor 10 constituting the active material layers 14 and 18 can be determined in the same manner.

[0075] First, the separator 15 is pulverized and immersed in a solvent to dissolve the ionic liquid contained in the separator 15. The ionic liquid is then separated into a solid component and a liquid component using a centrifuge. The Li content of the separated liquid component is determined by high-frequency inductively coupled plasma analysis (ICP).

[0076] Furthermore, the type of organic solvent contained in the separator 15 is determined by, for example, gas chromatography-mass spectrometry (GC-MS). The identified organic solvent (hereinafter referred to as a "standard substance") and the separator 15 are analyzed by thermogravimetric differential thermal analysis (TG-DTA). The analysis results of the standard substance are compared with the analysis results of the separator 15 to determine the content of the organic solvent contained in the separator 15. The molar concentration (mol / kg) of the lithium salt in the ionic liquid is calculated based on the Li content in the liquid component and the organic solvent content in the separator 15.

[0077] The content (volume %) of the solid electrolyte 19 and the ionic liquid is determined by freezing the separator 15 or embedding and securing it in a tetrafunctional epoxy resin or the like, then analyzing a randomly selected 5000x field of view from a cross section of the separator 15 using an SEM equipped with an energy-dispersive X-ray spectrometer (EDS). The analysis determines the distribution of La, Zr, and S or performs image analysis of the contrast of the reflected electron image to determine the area of ​​the solid electrolyte 19 and the area of ​​the ionic liquid. The ratio of the areas in the cross section of the separator 15 is then interpreted as the volume ratio of the separator 15 to the ion conductor 10, thereby determining the content (volume %) of the solid electrolyte 19 and the ionic liquid.

[0078] The Li ion conductivity of the ion conductor 10 is determined by the types of the solid electrolyte 19, lithium salt, and organic solvent, the salt concentration, etc. The lithium ion conductivity of the ion conductor 10 at 25° C. is preferably 1.0×10 -5 S / cm or more. This is to ensure the output density of the electricity storage device 11 including the ion conductor 10.

[0079] Since the ion conductor 10 contains anions derived from the lithium salt and the ionic liquid, the Li ion conductivity of the ion conductor 10 is calculated by multiplying the total ion conductivity calculated by the AC impedance method for a symmetrical cell in which current collectors are bonded to both surfaces of the sheet-shaped ion conductor 10 by the Li ion transference number. The Li ion transference number is determined by the AC impedance method and the steady-state DC method.

[0080] Reference Figure 4 The second embodiment will be described. In the first embodiment, the case where the ion conductor 10 is used in the electricity storage device 11 whose power generation element is made of a solid was described. In the second embodiment, the case where the ion conductor 10 is used in a liquid lithium-ion battery whose electrolyte uses an organic solvent will be described. Components identical to those described in the first embodiment are denoted by the same reference numerals, and the following description will be omitted. Figure 4 It is a cross-sectional view of the power storage device 22 in the second embodiment.

[0081] The storage device 22 includes a positive electrode layer 12, a separator 23, and a negative electrode layer 16 in this order. These are housed in a housing (not shown). The separator 23 is composed of a porous body that is durable to the active materials 20, 21 contained in the positive electrode layer 12 and the negative electrode layer 16, and the electrolyte, and that allows lithium ions to pass through but does not have electronic conductivity. The separator 23 can be exemplified by a non-woven fabric or a porous film composed of cellulose, polypropylene, polyethylene, polyimide, aluminum oxide, etc. The electrolyte containing an ionic liquid is the same as the electrolyte described in the first embodiment, so the description thereof is omitted.

[0082] The electricity storage device 22 in the second embodiment includes the ion conductor 10 in the positive electrode layer 12 and the negative electrode layer 16 . Therefore, similar to the electricity storage device 11 in the first embodiment, the operation stability is improved.

[0083] Reference Figure 5 The third embodiment will be described. In the first and second embodiments, the ion conductor 10 is included in the positive electrode layer 12, the separator 15, and the negative electrode layer 16. In the third embodiment, the ion conductor 10 is included in the protective layers 27 and 30. Components identical to those described in the first and second embodiments are denoted by the same reference numerals, and the following description will be omitted. Figure 5 It is a cross-sectional view of the power storage device 24 in the third embodiment.

[0084] The electricity storage device 24 includes a positive electrode layer 25, a separator 23, and a negative electrode layer 28 in this order. These are housed in a case (not shown). The electricity storage device 24 is a liquid lithium ion battery using an organic solvent as the electrolyte.

[0085] The positive electrode layer 25 is stacked with the current collecting layer 13 and the active material layer 26. The active material layer 26 contains the active material 20. To reduce the resistance of the active material layer 26, the active material layer 26 may contain a conductive additive such as carbon black, acetylene black, Ketjen black, carbon fiber, Ni, Pt, or Ag.

[0086] A protective layer 27 is disposed between the separator 23 and the negative electrode layer 28 . The protective layer 27 includes the ion conductor 10 .

[0087] The negative electrode layer 28 is stacked with an active material layer 29, a protective layer 30, and a current collector layer 17 in this order. The active material layer 29 is composed of, for example, Li, a Li-Al alloy, a Li-Sn alloy, a Li-Si alloy, a Li-Mg alloy, a Li-Si alloy, or a Si-Li alloy. The protective layer 30 includes the ion conductor 10. The protective layers 27 and 30 are formed by stacking sheets of a slurry containing the ion conductor 10, applying the slurry containing the ion conductor 10 to the separator 23 and the current collector layer 17, and the like.

[0088] Solid electrolyte 19, which contains Li, La, Zr, and O and has a garnet-type crystal structure and is resistant to reduction by the metallic lithium in active material layer 29, thereby increasing the operational stability of power storage device 24. Furthermore, protective layer 27, interposed between active material layer 29 and separator 23, suppresses short circuits caused by dendrite growth of metallic lithium. Protective layer 30, interposed between active material layer 29 and current collector layer 17, suppresses deterioration of current collector layer 17.

[0089] Reference Figure 6 The fourth to sixth embodiments will be described. Components identical to those described in the first to third embodiments are denoted by the same reference numerals, and the following description will be omitted. Figure 6 (a) is a cross-sectional view of an insulator 31 in the fourth embodiment.

[0090] The insulator 31 includes a diaphragm 23 and a protective layer 27 in contact with the diaphragm 23. The diaphragm 23 includes a first interface 32 and a second interface 33 opposite the first interface 32. The protective layer 27 is disposed on the first interface 32 and the second interface 33. The protective layer 27 disposed on the diaphragm 23 can reduce short circuits caused by dendrite growth of metallic lithium contained in the energy storage device. Even if the energy storage device shorts and the diaphragm 23 is thermally deformed, the protective layer 27 can maintain the shape of the diaphragm 23, thereby suppressing thermal runaway of the energy storage device.

[0091] Figure 6 (b) is a cross-sectional view of an electrode 34 in the fifth embodiment. The electrode 34 includes a positive electrode layer 12 and a protective layer 27 in contact with the active material layer 14 of the positive electrode layer 12. The electrode 34 has the protective layer 27 disposed at an interface 35 of the active material layer 14 opposite to the surface on which the current collector layer 13 is disposed. The protective layer 27 disposed at the interface 35 with the active material layer 14 can reduce dendrite growth from the negative electrode layer 16 of the energy storage device.

[0092] Figure 6 (c) is a cross-sectional view of an electrode 36 in the sixth embodiment. The electrode 36 includes a negative electrode layer 16 and a protective layer 27 in contact with the active material layer 18 of the negative electrode layer 16. The protective layer 27 is disposed at an interface 37 of the active material layer 18 opposite to the surface on which the current collector layer 17 is disposed. The protective layer 27 disposed at the interface 37 with the active material layer 18 can reduce dendrite growth from the negative electrode layer 16 of the energy storage device.

[0093] The insulator 31 is disposed in the power storage device in place of the separator 23 of the power storage device 22 in the second embodiment and the power storage device 24 in the third embodiment. The insulator 31 may omit one of the two protective layers 27 disposed at the interfaces 32 and 33 of the separator 23.

[0094] The electrode 34 is provided in the power storage device in place of the positive electrode layers 12 and 25 of the power storage device 22 and the power storage device 24 in the second embodiment. The electrode 36 is provided in the power storage device in place of the negative electrode layers 16 and 28 of the power storage device 22 and the power storage device 24 in the third embodiment.

[0095] Example

[0096] The present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[0097] (Example 1)

[0098] To become Li 6.95 Mg 0.15 La 2.75 Sr 0.25 Zr 2.0 O 12 Li2CO3, MgO, La(OH)3, SrCO3, and ZrO2 are weighed in a certain manner. Considering the volatilization of Li during sintering, Li2CO3 is used in an excess of about 15 mol% in terms of element conversion. The weighed raw materials and organic solvent are put into a nylon pot together with zirconium oxide balls, and crushed and mixed in a ball mill for 15 hours. The slurry taken out of the pot is dried, placed on a plate made of MgO, and pre-fired at 900°C for 1 hour and at 1200°C for 10 hours. The obtained pre-fired body is placed on a plate made of MgO and sintered at 1100°C for 4 hours in an inert gas atmosphere to obtain a sintered body.

[0099] The calcined product was wet-pulverized in a planetary ball mill without exposure to air and then dried to obtain a powder with a particle size ranging from submicron to several microns. The powder was stored in Ar at a dew point of -80°C for one week to obtain the solid electrolyte of Example 1.

[0100] The lithium salt LiN(SO2F)2(LiFSI) was dissolved in the ionic liquid N-methyl-N-propylpyrrolidine in such a way that the salt concentration reached 2.3 mol / kg. An ionic liquid obtained by mixing bis(fluorosulfonyl)imide (P13FSI) with a solid electrolyte was mixed in a mortar in an Ar atmosphere glove box to a solid electrolyte:ionic liquid ratio of 80:20 (volume ratio). This yielded a composite powder containing the ionic liquid and the solid electrolyte. The composite powder was heated at 60°C for 1 hour under an Ar atmosphere to obtain the ion conductor of Example 1.

[0101] (Example 2)

[0102] A solid electrolyte and an ion conductor in Example 2 were obtained in the same manner as in Example 1 except that the powder was stored in dry air with a dew point of -40°C for one week.

[0103] (Comparative Example)

[0104] A solid electrolyte and an ion conductor in a comparative example were obtained in the same manner as in Example 1 except that the powder was stored in an atmosphere at a temperature of 25° C. and a humidity of 30% for one week.

[0105] (Determination of ionic conductivity)

[0106] The ion conductors of Examples 1, 2, and the comparative example were placed in an insulating cylinder with a 10 mm diameter hole in an Ar atmosphere. A pressure of 360 MPa was applied to the ion conductors using cylindrical stainless steel electrodes placed on both sides of the cylinder, forming them into a disc shape. Ionic conductivity was measured by AC impedance spectroscopy while pressure was applied. The ion conductivity was measured at a temperature of 25°C, a voltage of 10 mV, and a frequency of 7 MHz to 100 MHz.

[0107] (Determination of lithium ion conductivity)

[0108] After measuring ionic conductivity, the molded body was removed from the cylinder. After attaching 9mm diameter Li foil to both sides of the molded body, 10mm diameter Cu foil was placed in the cylinder, with the Li foil attached to each side of the molded body. The Cu foil was tightened to an 8N torque and applied with an axial force to the Cu foil, resulting in a symmetrical cell in which the Li foil was tightly bonded to the molded body.

[0109] First, the current value I after a constant voltage V is applied to the symmetrical battery and the steady state is measured, and the current value I is obtained from R P =V / I to calculate the steady-state resistance R of the symmetrical battery. P The measurement conditions for the current value in the steady state were set as a voltage of 3 mV, a total time of 4 hours, and a measurement interval of 60 seconds.

[0110] Next, the resistance value R of the symmetrical battery that has reached a steady state is measured by AC impedance. S and interface resistance R INT The conditions for the AC impedance measurement were set at a temperature of 25° C., a voltage of 10 mV, and a frequency of 7 MHz to 100 MHz.

[0111] Set the resistance value R S , resistance value R P and interface resistance R INT Substitute the migration number t of lithium ions Li =R S / (R P -RINT ) and calculate the migration number t Li Multiply the ionic conductivity by the migration number t Li The lithium ion conductivity was calculated. Table 1 shows the ion conductivity, transference number, and lithium ion conductivity.

[0112]

[0113] As shown in Table 1, the lithium ion transference number decreases in the order of Example 1, Example 2, and Comparative Example, and the lithium ion conductivity also decreases in the order of Example 1, Example 2, and Comparative Example. The lithium ion conductivity of the Comparative Example is less than half that of Examples 1 and 2. To investigate the causes of the differences in lithium ion conductivity and transference number, analysis of the interface between the solid electrolyte and the ionic liquid, as well as analysis of the interface between lithium carbonate and the ionic liquid, was conducted.

[0114] (Preparatory experiment)

[0115] XPS was used to investigate the reaction products at the interface between the solid electrolyte and the ionic liquid, and the reaction products at the interface between the lithium carbonate and the ionic liquid. A sintered body was used for the solid electrolyte, and a powder compact was used for the lithium carbonate.

[0116] The sintered body of the solid electrolyte was prepared as follows. The pre-calcined body and the organic solvent before obtaining the solid electrolyte in Example 1 were put into a nylon can and pulverized and mixed using a ball mill for 15 hours. The slurry taken out from the can was dried and put into a mold with a diameter of 12 mm. A molded body with a thickness of about 1.5 mm was obtained by pressing. The molded body was further subjected to a 1.5t / cm 2 The formed body was covered with a pre-calcined body having the same composition as the formed body, and calcined at 1100° C. for 4 hours in an inert gas atmosphere to obtain a sintered body.

[0117] After polishing the flat surface of the sintered body in an Ar atmosphere, an ionic liquid containing LiFSI dissolved in P13FSI at a salt concentration of 2.1 mol / kg was immediately added dropwise to the polished surface. After allowing the solution to stand, the ionic liquid on the polished surface was wiped off with a paper wipe. The sintered body was sealed in an Ar atmosphere and placed in a transfer container, and the polished surface was analyzed using XPS.

[0118] The pressed powder compact of lithium carbonate is obtained by placing lithium carbonate (special grade) powder in a cylinder made of an insulator with a hole diameter of 10 mm and applying a pressure of 360 MPa to the powder using a stainless steel cylindrical rod inserted from both sides of the cylinder. An ionic liquid with a salt concentration of 2.1 mol / kg of LiFSI dissolved in P13FSI is added dropwise to the flat surface of the compact. After standing, the ionic liquid on the surface of the compact is wiped off with a wipe, and the surface of the compact is analyzed by XPS.

[0119] For comparison, an ionic liquid with a salt concentration of 2.1 mol / kg, obtained by dissolving LiFSI in P13FSI, was added dropwise to the surface of a sintered body of high-purity alumina (Al2O3 99.5%, water absorption rate less than 0.01%). After standing, the ionic liquid on the surface of the sintered body was wiped off with a wipe paper, and the surface of the sintered body was analyzed by XPS.

[0120] XPS conditions for all three samples were monochromatized AlKα X-rays, a transmission energy of 140 eV, and an analysis area of ​​100 μm. The analysis revealed a spectrum at 688 eV (F1s) attributed to the SF bond in the ionic liquid, spectra attributed to C-N and S-N bonds (N1s), and spectra attributed to S=O bonds (S2p), but no spectra attributed to lithium compounds such as LixN and LixSOy were observed. A spectrum at 685 eV (F1s) attributed to fluorides chemically bonded to the solid electrolyte was observed on the polished surface of the solid electrolyte, but this spectrum was not observed in the other two samples.

[0121]

[0122] Table 2 shows the results of calculating the area intensity from the 688eV (F1s) spectrum of the residue from the ionic liquid and the 685eV (F1s) spectrum from the fluoride chemically bonded to the solid electrolyte, and measuring the atomic concentration (atom %) of the ionic liquid and the fluoride by the relative sensitivity factor method using the sensitivity coefficient inherent in the device.

[0123] As shown in Table 2, it was confirmed that the atomic concentration (SF) of the residue from the ionic liquid on the surface of the sample was the same in all three samples. It was also confirmed that the atomic concentration of the fluoride detected in lithium carbonate was the same as the atomic concentration of the fluoride detected in aluminum oxide. That is, the atomic concentration of the fluoride detected in lithium carbonate was within the range of error, and thus it was confirmed that the solid electrolyte reacted with the fluorine-based anions of the ionic liquid to generate a compound on the surface of the solid electrolyte, but lithium carbonate did not react with the ionic liquid.

[0124] (Analysis of Solid Electrolyte)

[0125] Next, the surfaces of the solid electrolyte powders from Examples 1, 2, and the comparative example were analyzed. Each solid electrolyte powder was sealed in a transfer container under an Ar atmosphere, and the surface of each solid electrolyte was analyzed using XPS. XPS conditions were monochromatized AlKα X-rays, a flux of 140 eV, and an analysis area of ​​100 μm.

[0126] The area intensities of the peak intensity of zirconium from the solid electrolyte and the peak intensity of 289 eV (C1s) from lithium carbonate (carbonate ions) generated on the surface of the solid electrolyte were calculated. The atomic concentrations (atom %) of zirconium and carbonate ions were measured using the relative sensitivity factor method using the sensitivity coefficient inherent in the device. The relative concentration ratio of the atomic concentration of zirconium to the atomic concentration of carbonate ions, Zr / CO3, was calculated. The relative concentration ratios are listed in Table 1.

[0127] (Analysis of ion conductors)

[0128] In an Ar atmosphere, the ion conductors from Examples 1, 2, and the comparative example were placed in an insulating cylinder with a 10 mm diameter hole. A pressure of 360 MPa was applied to the ion conductors using stainless steel cylindrical rods inserted from both sides of the cylinder to produce disc-shaped molded bodies. The molded bodies were removed from the cylinder, and cross-sections of the molded bodies were prepared. These samples were then sealed in a transfer container under Ar atmosphere, and the cross-sections of each sample were analyzed using XPS. XPS conditions were monochromatized AlKα X-rays, a flux of 140 eV, and an analysis area of ​​100 μm.

[0129] The area intensities of the peak intensity of 685 eV (F1s) of fluoride chemically bonded to the surface of the solid electrolyte and the peak intensity of 289 eV (C1s) of lithium carbonate (carbonate ions) generated on the surface of the solid electrolyte were calculated respectively. The atomic concentrations (atom %) of fluoride and carbonate ions were measured by the relative sensitivity factor method using the sensitivity coefficient inherent in the device, and the relative concentration ratio F / CO3 of the atomic concentration of fluoride to the atomic concentration of carbonate ions was calculated. The relative concentration ratios are recorded in Table 1.

[0130] (result)

[0131] The relative concentration ratio of Zr / CO3 on the surface of the solid electrolyte powder was 0 in the Comparative Example. No zirconium was observed in the Comparative Example, indicating that at least the entire XPS analysis area on the surface of the solid electrolyte powder in the Comparative Example was covered with lithium carbonate. In contrast, the relative concentration ratio of Zr / CO3 was 0.85 in Example 1 and 0.03 in Example 2. This indicates that lithium carbonate was locally present in the XPS analysis area on the surface of the solid electrolyte powder in Examples 1 and 2.

[0132] The relative atomic concentration ratio F / CO3 on the surface of the solid electrolyte in the ion conductor was 0.04 in the comparative example. As mentioned above, preliminary experiments confirmed that the surface of the solid electrolyte in the comparative example was lithium carbonate, which does not react with the ionic liquid. Therefore, the fluoride detected in the comparative example is believed to be the result of surface contamination during sample processing.

[0133] In contrast, the relative concentration ratio F / CO3 in Example 1 was 0.31, and in Example 2 it was 0.19. This indicates that lithium carbonate and fluoride are present in the XPS analysis area of ​​the solid electrolyte surface in the ion conductors of Examples 1 and 2. The higher migration numbers of the ion conductors in Examples 1 and 2 than in the comparative example, and the fact that the lithium ion conductivity of the ion conductors in Examples 1 and 2 is more than twice that of the ion conductor in the comparative example, can be inferred to be the influence of the film containing fluoride formed on the surface of the solid electrolyte powder. The examples show that the local presence of lithium carbonate on the surface of the solid electrolyte powder can control lithium ion conductivity.

[0134] As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to the said embodiment at all, It can be easily estimated that various improvements and modifications can be made within the range which does not deviate from the summary of this invention.

[0135] In the embodiments, an energy storage device 11 is described as comprising a positive electrode layer 12 having an active material layer 14 provided on one side of a current collecting layer 13, and a negative electrode layer 16 having an active material layer 18 provided on one side of a current collecting layer 17. However, the present invention is not necessarily limited to this embodiment. For example, the various elements of the embodiments can be applied to an energy storage device comprising electrode layers (so-called bipolar electrodes) in which the active material layers 14 and 18 are provided on both sides of the current collecting layer 13, respectively. By alternately stacking the bipolar electrodes and the separator 15 and housing them in a housing (not shown), an energy storage device with a so-called bipolar structure can be obtained.

[0136] In the embodiment, the active material layers 14 and 18 and the separator 15 are all made of the ion conductor 10 . However, the present invention is not necessarily limited thereto.

[0137] In the embodiments, the ion conductor 10 is described by taking the power storage devices 11, 22, and 24 as lithium ion batteries, but the present invention is not necessarily limited thereto. Other power storage devices including the ion conductor 10 include lithium ion capacitors, lithium sulfur batteries, lithium oxygen batteries, and lithium air batteries.

[0138] Explanation of symbols

[0139] 10 Ionic Conductors

[0140] 11, 22, 24 Energy storage devices

[0141] 12, 25 positive electrode layer (sheet, electrode)

[0142] 15 diaphragm (sheet)

[0143] 16, 28 negative electrode layer (sheet, electrode)

[0144] 19 Solid Electrolyte

[0145] 19a Lithium carbonate

[0146] 19c membrane

[0147] 19d complex

[0148] 23 diaphragm

[0149] 27, 30 protective layer

[0150] 34, 36 electrodes

Claims

1. An ion conductor comprising a solid electrolyte having a garnet-type crystal structure containing Li, La, Zr, and O, wherein: Lithium carbonate exists locally on the surface of the solid electrolyte.

2. The ion conductor according to claim 1, wherein A relative concentration ratio of zirconium to carbonate ions on the surface of the solid electrolyte is 0.01 or greater.

3. A composite comprising the ion conductor according to claim 1 or 2 and an ionic liquid in which a lithium salt is dissolved, wherein: The ionic liquid contains fluorine anions, The composite body includes a film covering the surface of the solid electrolyte, The relative concentration ratio of fluoride to carbonate ions in the film is 0.1 or more.

4. The complex according to claim 3, wherein The solid electrolyte further contains Mg and Sr, and does not contain F. A sheet comprising the ion conductor according to claim 1 or 2. An electrode comprising the ion conductor according to claim 1 or 2. 7 . A separator comprising the ion conductor according to claim 1 . 8 . An electrode in contact with a protective layer, wherein the protective layer comprises the ion conductor according to claim 1 . 9 . A separator in contact with a protective layer, wherein the protective layer comprises the ion conductor according to claim 1 . 10 . An electricity storage device comprising the electrode according to claim 6 . 11 . An electricity storage device comprising the separator according to claim 7 . 12 . An electricity storage device comprising the electrode according to claim 8 . 13 . An electricity storage device comprising the separator according to claim 9 .

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