Solid electrolyte materials and batteries

Abstract

A solid electrolyte material capable of suppressing a decrease in ionic conductivity is provided. The solid electrolyte material includes a polymer electrolyte, an inorganic filler, and succinonitrile, wherein the polymer electrolyte includes an anionic polymer.

Description

[Technical Field]

[0001] The present disclosure relates to solid electrolyte materials and batteries. [Background technology]

[0002] Various techniques have been proposed regarding solid electrolyte materials such as those disclosed in Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-091813 [Patent Document 2] International Publication No. 2021 / 166975 [Patent Document 3] International Publication No. 2022 / 102767 Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 discloses a solid electrolyte that uses plastic crystals in the solid electrolyte to improve the ionic conductivity of the solid electrolyte, and that can exhibit high ionic conductivity even in the low temperature range, which is a problem with plastic crystals. However, if the solid electrolyte is stored for a long period of time under low temperature conditions, the plastic crystals will crystallize, resulting in a decrease in ionic conductivity. Patent Document 2 discloses a solid electrolyte that contains molecular crystals and an inorganic filler, and thereby has excellent flexibility and ionic conductivity. However, the molecular crystals are polymerized, and the effects of the plastic crystal structure cannot be fully exhibited.

[0005] The present disclosure has been made in view of the above circumstances, and has as its main object to provide a solid electrolyte material capable of suppressing a decrease in ionic conductivity. [Means for solving the problem]

[0006] That is, the present disclosure includes the following aspects. <1> The polymer electrolyte includes an inorganic filler and succinonitrile, The solid electrolyte material is characterized in that the polymer electrolyte contains an anionic polymer.

[0007] <2> The inorganic filler is contained in an amount of 1% by mass or more and 10% by mass or less relative to the total amount of the solid electrolyte material. <1> The solid electrolyte material according to claim 1.

[0008] <3> The inorganic filler is SiO2. <1> or <2> The solid electrolyte material according to claim 1.

[0009] <4> The inorganic filler is Al2O3. <1> or <2> The solid electrolyte material according to claim 1.

[0010] <5> The polymer electrolyte contains at least one of a bis(fluorosulfonyl)imide anion and a bis(trifluoromethanesulfonyl)imide anion. <1> ~ <4> 10. The solid electrolyte material according to claim 9, wherein the first and second electrodes are electrically connected to each other.

[0011] <6> The polymer electrolyte contains at least one of poly((trifluoromethane)sulfonimide lithium methacrylate) and poly(styrene-4-sulfonyltrifluoromethylsulfonyl)imide lithium; <1> ~ <5> 10. The solid electrolyte material according to claim 9, wherein the first and second electrodes are electrically connected to each other.

[0012] <7> A battery having a positive electrode layer, a negative electrode layer, and an electrolyte layer, the negative electrode layer contains, as a negative electrode active material, at least one of Li elemental substance and a Li alloy, the electrolyte layer includes a solid electrolyte and an electrolyte solution, The solid electrolyte is <1> ~ <6> A battery comprising the solid electrolyte material according to any one of the above items.

[0013] <8> An all-solid-state battery having a positive electrode layer, a negative electrode layer, and a solid electrolyte layer, the negative electrode layer contains, as a negative electrode active material, at least one of Li elemental substance and a Li alloy, the solid electrolyte layer includes a solid electrolyte, The solid electrolyte is <1> ~ <6> 10. An all-solid-state battery comprising the solid electrolyte material according to any one of claims 1 to 9. [Effects of the Invention]

[0014] The present disclosure has an effect of providing a solid electrolyte material capable of suppressing a decrease in ionic conductivity. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic cross-sectional view illustrating a battery according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments of the present disclosure will be described. It should be noted that matters other than those specifically mentioned in this specification that are necessary for implementing the present disclosure (for example, the general configuration and manufacturing process of solid electrolyte materials that do not characterize the present disclosure) can be understood as design matters for those skilled in the art based on prior art in the relevant field. The present disclosure can be implemented based on the contents disclosed in this specification and common general technical knowledge in the relevant field. In the present disclosure, unless otherwise specified, the average particle size of particles is the median diameter (D50) value, which is the particle size at 50% of the cumulative value in the volume-based particle size distribution measured by laser diffraction / scattering particle size distribution measurement.

[0017] A. Solid electrolyte material In the present disclosure, a polymer electrolyte, an inorganic filler, and succinonitrile (hereinafter, sometimes referred to as SN), The present invention provides a solid electrolyte material, wherein the polymer electrolyte contains an anionic polymer.

[0018] The solid electrolyte material includes a polymer electrolyte, an inorganic filler, and succinonitrile.

[0019] A polymer electrolyte is a substance that is in a solid state at room temperature and easily migrates ions when an external electric field is applied. In the present invention, a solid refers to a substance that maintains its shape regardless of the shape of the container. The weight average molecular weight of the polymer electrolyte is not particularly limited, but may be from 10,000 to 200,000, or from 50,000 to 100,000. The polymer electrolyte comprises an anionic polymer. An anionic polymer is a polymer having two or more monomer units having an anionic group in the molecule. The polymer electrolyte may contain at least one of a bis(fluorosulfonyl)imide (FSI) anion and a bis(trifluoromethanesulfonyl)imide (TFSI) anion as the anion of the anionic polymer. Examples of anionic polymers include polybis(fluorosulfonyl)imide (FSI), polybis(trifluoromethanesulfonyl)imide (TFSI), polyacrylic acid, polymethacrylic acid, acrylic acid / (meth)acrylate alkyl copolymer, carboxyvinyl polymer, and polystyrene sulfonate, as well as metal salts thereof. Examples of cations constituting the metal salts include sodium ions, potassium ions, lithium ions, magnesium ions, and calcium ions. The polymer electrolyte is an anionic polymer, Poly((trifluoromethane)sulfonimide lithium methacrylate): abbreviated as PMTFSI-Li, represented by the following chemical formula (1): Poly(styrene-4-sulfonyltrifluoromethylsulfonyl)imide lithium (abbreviated as PSTFSI-Li) represented by the following chemical formula (2): Lithium polyacrylate represented by the following chemical formula (3), and It may be lithium polystyrene sulfonate, etc., represented by the following chemical formula (4).

[0020] [ka]

[0021] [ka]

[0022] [ka]

[0023] [ka]

[0024] Succinonitrile is a plastic crystal that exists as NCCH2CH2CN, which can act as a solid solvent to enhance the ionic conductivity of polymer electrolytes. The molar ratio of succinonitrile to 1 mole of polymer electrolyte is, for example, 1 to 10 moles, or may be 2 to 4 moles, from the viewpoint of increasing the ionic conductivity of the polymer electrolyte.

[0025] The inorganic filler is used to suppress the crystallization of succinonitrile. Examples of inorganic fillers include SiO2, Al2O3, TiO2, ZrO2, and MgO. The inorganic filler may be contained in an amount of 1% by mass to 10% by mass of the total amount of the solid electrolyte material. If the amount is less than 1% by mass, the crystallization suppression effect of succinonitrile may not be sufficiently obtained. If the amount is more than 10% by mass, the desired ionic conductivity of the polymer electrolyte may not be obtained. The mass % of the inorganic filler can be determined by dissolving the solid electrolyte material, the mass of which has been measured in advance, in a polar solvent such as acetonitrile or dimethyl carbonate, extracting only the inorganic filler that is insoluble in the solvent, and measuring the mass. The average particle size of the inorganic filler is not particularly limited, but may be, for example, 0.1 μm to 0.2 μm. In the present disclosure, the presence of an inorganic filler suppresses crystallization of succinonitrile, a plastic crystal, even when the crystal is stored for a long period of time under low-temperature conditions, thereby extending the supercooling life of the plastic crystal and suppressing a decrease in ionic conductivity when stored under low-temperature conditions.

[0026] B.Battery The battery in the present disclosure has a positive electrode layer, a negative electrode layer, and an electrolyte layer, and typically has a positive electrode including a positive electrode layer and a negative electrode including a negative electrode layer. Fig. 1 is a schematic cross-sectional view illustrating a battery according to the present disclosure. The battery 10 shown in Fig. 1 includes a positive electrode layer 1, a negative electrode layer 2, an electrolyte layer 3 disposed between the positive electrode layer 1 and the negative electrode layer 2, a positive electrode current collector 4 that collects current from the positive electrode layer 1, and a negative electrode current collector 5 that collects current from the negative electrode layer 2. In the present disclosure, the electrolyte layer 3 includes the solid electrolyte material described above in "A. Solid Electrolyte Material." According to the present disclosure, by using the above-described solid electrolyte material, a battery with a small increase in resistance is obtained.

[0027] [Positive electrode] The positive electrode has a positive electrode layer and, if necessary, further has a positive electrode current collector. The positive electrode layer is a layer containing at least a positive electrode active material, and may also contain at least one of a solid electrolyte, a conductive material, and a binder, as necessary.

[0028] Examples of the positive electrode active material include oxide active materials, such as LiCoO2, LiMnO2, LiNiO2, LiVO2, and LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, etc., rock salt layered active materials, LiMn2O4, Li4Ti5O 12 , and Li(Ni 0.5 Mn 1.5 and olivine type active materials such as LiFePO4, LiMnPO4, LiNiPO4, and LiCoPO4. A coating layer containing a Li-ion conductive compound may be formed on the surface of the positive electrode active material. This is because it can suppress the reaction between the positive electrode active material and the solid electrolyte (particularly a sulfide solid electrolyte). Examples of Li-ion conductive compounds include B2O3, Li2B4O7, LiBPO4, Li3PO4, LiPO3, and LiNbO3. The thickness of the coating layer is, for example, 1 nm or more and 30 nm or less. The coverage of the Li-ion conductive compound that coats the positive electrode active material is, for example, 70% or more, or may be 90% or more, or even 100%. The method for coating the Li-ion conductive compound is not particularly limited, and any conventionally known method can be used as appropriate.

[0029] The positive electrode active material is usually in the form of particles, and may be in the form of primary particles or secondary particles formed by aggregation of primary particles. The average particle size (D50) of the positive electrode active material is not particularly limited, but may be, for example, 0.01 μm or more and 50 μm or less, or 0.5 μm or more and 30 μm or less.

[0030] The proportion of the positive electrode active material in the positive electrode layer is, for example, 20% by mass or more, or may be 30% by mass or more, or 40% by mass or more. If the proportion of the positive electrode active material is too low, sufficient energy density may not be obtained. On the other hand, the proportion of the positive electrode active material in the positive electrode layer is, for example, 80% by mass or less, or may be 70% by mass or less, or may be 60% by mass or less. If the proportion of the positive electrode active material is too high, the ionic conductivity and electronic conductivity of the positive electrode layer may relatively decrease.

[0031] The positive electrode layer may contain a solid electrolyte. Addition of the solid electrolyte improves the ionic conductivity of the positive electrode layer. The solid electrolyte may be an inorganic solid electrolyte such as a sulfide solid electrolyte, a halide solid electrolyte, an oxide solid electrolyte, or a complex hydride solid electrolyte, or may be an organic solid electrolyte such as a gel electrolyte. The solid electrolyte may be any of the solid electrolyte materials described above.

[0032] The sulfide solid electrolyte is an electrolyte containing the element S. The sulfide solid electrolyte usually contains at least the elements Li and S. The sulfide solid electrolyte may further contain the element Me (Me is at least one of P, As, Sb, Si, Ge, Sn, B, Al, Ga, and In). The sulfide solid electrolyte may also contain halogen elements such as F, Cl, Br, and I.

[0033] The sulfide solid electrolyte may be a glass-based (amorphous) sulfide solid electrolyte, a glass-ceramic sulfide solid electrolyte, or a crystalline sulfide solid electrolyte. The sulfide solid electrolyte may have a crystalline phase. Examples of the crystalline phase include a Thio-LISICON-type crystalline phase, an Argyrodite-type crystalline phase, and an LGPS-type crystalline phase.

[0034] The composition of the sulfide solid electrolyte is not particularly limited. For example, xLi2S·(1 - x)P2S5 (0.5 ≦ x < 1), and yLiI·zLiBr·(100 - y - z)(xLi2S·(1 - x)P2S5) (0.5 ≦ x < 1, 0 ≦ y ≦ 30, 0 ≦ z ≦ 30), etc. may be mentioned. In these compositions, x may satisfy 0.7 ≦ x ≦ 0.8. Also, as another example of the composition of the sulfide solid electrolyte, Li 7-x PS 6-x X x may be mentioned. X is at least one of F, Cl, Br, and I, and x satisfies 0 ≦ x < 2. Also, as another example of the composition of the sulfide solid electrolyte, Li 4-x Me 1-x P x S4 (0 < x < 1) may be mentioned. Me is at least one of Al, Zn, In, Ge, Si, Sn, Sb, Ga, and Bi. Examples of the sulfide solid electrolyte include LiI - LiBr - Li2S - P2S5, LiI - Li2S - P2S5, LiI - Li2S - P2O5, and LiI - Li3PO4 - P2S5, etc.

[0035] Examples of the oxide solid electrolyte include substances having a garnet - type crystal structure having, for example, an Li element, a La element, an A element (A is at least one of Zr, Nb, Ta, and Al), and an O element. Examples of the oxide solid electrolyte include, for example, Li2O - B2O3 - P2O5, Li2O - SiO2, Li2O - B2O3, Li 1.3 Al 0.3 Ti 0.7 (PO4)3, Li5La3Ta2O 12 , Li7La3Zr2O 12 , Li6BaLa2Ta2O 12 , Li 3.6 Si 0.6 P 0.4 O4, Li4SiO4, Li3PO4, and Li 3+x PO 4-x N x (1 ≦ x ≦ 3) etc. may also be possible.

[0036] The halide solid electrolyte may be, for example, a solid electrolyte containing Li, M, and X (M represents at least one of Ti, Al, and Y, and X represents F, Cl, or Br).

[0037] The solid electrolyte may be in the form of particles from the viewpoint of ease of handling. The average particle size (D50) of the solid electrolyte particles is not particularly limited and may be from 1 nm to 100 μm.

[0038] The proportion of the solid electrolyte in the positive electrode layer is, for example, 10% by mass or more, or may be 20% by mass or more, or may be 30% by mass or more. If the proportion of the solid electrolyte is too low, the ion conduction paths in the positive electrode layer may be insufficient. On the other hand, the proportion of the solid electrolyte in the positive electrode layer is, for example, 60% by mass or less, or may be 50% by mass or less. If the proportion of the solid electrolyte is too high, the proportion of the positive electrode active material may be relatively low, and the energy density may be low.

[0039] The positive electrode layer may contain a conductive material. The addition of the conductive material improves the electronic conductivity of the positive electrode layer. Examples of the conductive material include carbon materials, metal particles, and conductive polymers. Examples of the carbon material include particulate carbon materials such as acetylene black (AB) and ketjen black (KB), and fibrous carbon materials such as vapor grown carbon fiber (VGCF), carbon nanotubes (CNT), and carbon nanofibers (CNF).

[0040] The proportion of the conductive material in the positive electrode layer is, for example, 0.1% by mass or more, or may be 0.5% by mass or more, or may be 1.0% by mass or more. If the proportion of the conductive material is too low, the electron conduction path in the positive electrode layer may be insufficient. On the other hand, the proportion of the conductive material in the positive electrode layer is, for example, 5% by mass or less, or may be 3% by mass or less. If the proportion of the conductive material is too high, the proportion of the positive electrode active material may be relatively low, which may result in a low energy density.

[0041] The positive electrode layer may contain a binder, such as styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), butadiene rubber (BR), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), styrene-isoprene-styrene block copolymer (SIS), and ethylene-propylene-diene copolymer (EPDM).

[0042] The proportion of the binder in the positive electrode layer may be, for example, 0.5% by mass or more, 1.0% by mass or more, or 1.5% by mass or more. If the proportion of the binder is too low, it may be difficult to sufficiently reduce the increase in resistance due to charging and discharging. On the other hand, the proportion of the binder in the positive electrode layer may be, for example, 5% by mass or less, or 3% by mass or less. If the proportion of the binder is too high, the proportion of the positive electrode active material may be relatively low, which may result in a low energy density.

[0043] The thickness of the positive electrode layer is, for example, 0.1 μm or more and 1000 μm or less, or may be 1 μm or more and 500 μm or less, or may be 30 μm or more and 100 μm or less.

[0044] The method for producing the positive electrode layer is not particularly limited, but examples thereof include a method in which the positive electrode active material, the solid electrolyte, and a solvent are mixed to obtain a positive electrode slurry, and the positive electrode slurry is applied to a positive electrode current collector and dried to form the positive electrode layer. When forming the positive electrode layer, a pressing process may be performed to press the positive electrode layer in the thickness direction. Examples of pressing processes include a roller press and a flat plate press. Examples of the solvent include tetralin, diisobutyl ketone, butyl butyrate, mesitylene, heptane, dibutyl ether, decane, dodecane, isodecane, and toluene, and the solvent may contain two or more of these components.

[0045] Examples of materials for the positive electrode current collector include SUS, Cr, Au, Pt, Zn, aluminum, copper, nickel, iron, titanium, and carbon. The thickness of the positive electrode current collector is, for example, 0.1 μm or more and 100 μm or less. The shape of the positive electrode current collector may be foil, plate, or the like. The planar shape of the positive electrode current collector is not particularly limited, and examples include a circle, an ellipse, a rectangle, and any polygonal shape. The positive electrode current collector may have a buffer layer, an elastic layer, or a PTC (Positive Temperature Coefficient) thermistor layer disposed on its surface.

[0046] [Negative electrode] The negative electrode has a negative electrode layer and, if necessary, further has a negative electrode current collector. The negative electrode layer is a layer containing at least a negative electrode active material, and may also contain at least one of a solid electrolyte, a conductive material, and a binder, as necessary. The negative electrode layer contains at least one of elemental Li and a Li alloy as the negative electrode active material, and examples of metal elements other than lithium contained in the Li alloy include Mg, Ag, In, Sn, Si, Ga, Au, and Pt. The solid electrolyte, conductive material, and binder used in the negative electrode layer may be the same as those described above for the positive electrode layer.

[0047] Examples of materials for the negative electrode current collector include SUS, aluminum, copper, nickel, iron, titanium, and carbon. The thickness of the negative electrode current collector varies depending on the shape, but may be, for example, within a range of 1 μm to 50 μm. The shape of the negative electrode current collector may be a foil, a plate, or the like. The shape of the negative electrode current collector in plan view is not particularly limited, but examples include a circle, an ellipse, a rectangle, and any polygonal shape. The negative electrode current collector may have a buffer layer, an elastic layer, or a PTC thermistor layer disposed on its surface.

[0048] [Electrolyte layer] The electrolyte layer is a layer formed between the positive electrode layer and the negative electrode layer, and contains at least an electrolyte. The electrolyte may be a solid electrolyte or a liquid electrolyte (electrolytic solution). The electrolyte layer may include a solid electrolyte and an electrolyte solution. The solid electrolyte is the solid electrolyte material described above in "A. Solid Electrolyte Material." The proportion of the solid electrolyte in the electrolyte layer is not particularly limited, but is, for example, 50% by mass or more, and may be in the range of 60% by mass to 100% by mass, 70% by mass to 100% by mass, or even 100% by mass. The electrolyte layer may contain less than 10% by mass of the electrolytic solution relative to the total amount of the electrolyte layer. The ionic conductivity of the electrolyte layer may be improved by including an electrolytic solution. However, in order to avoid a decrease in mechanical strength at high temperatures, the electrolyte solution may be included in an amount of, for example, less than 10 mass %, 5 mass % or less, 1 mass % or less, or 0.5 mass % or less relative to the total amount of the electrolyte layer. The electrolyte may be an aqueous electrolyte, a non-aqueous electrolyte, or the like, and may be used alone or in combination of two or more.

[0049] The solvent of the aqueous electrolyte solution contains water as a main component. That is, based on the total amount (100 mol%) of the solvent (liquid component) constituting the electrolyte solution, water may account for 50 mol% or more, particularly 70 mol% or more, and even 90 mol% or more. Meanwhile, there is no particular upper limit to the proportion of water in the solvent.

[0050] The solvent contains water as a main component, but may contain a solvent other than water. Examples of the solvent other than water include one or more selected from ethers, carbonates, nitriles, alcohols, ketones, amines, amides, sulfur compounds, and hydrocarbons. The solvent other than water may be 50 mol% or less, particularly 30 mol% or less, and even 10 mol% or less, based on the total amount (100 mol%) of the solvents (liquid components) constituting the electrolytic solution.

[0051] The aqueous electrolyte used in the present disclosure includes an electrolyte. Conventionally known electrolytes can be used for aqueous electrolytes. Examples of the electrolyte include lithium salts, nitrates, acetates, and sulfates of imide acid compounds. Specific examples of the electrolyte include lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(pentafluoroethanesulfonyl)imide (LiBETI), lithium bis(nonafluorobutanesulfonyl)imide, lithium nonafluoro-N-[(trifluoromethane)sulfonyl]butanesulfonylamide, lithium N,N-hexafluoro-1,3-disulfonylimide, CHClCOOLi, LiPF, LiBF, LiSO, and LiNO.

[0052] The concentration of the electrolyte in the aqueous electrolyte solution can be appropriately set according to the desired battery characteristics, as long as it does not exceed the saturated concentration of the electrolyte in the solvent, because if a solid electrolyte remains in the aqueous electrolyte solution, the solid may inhibit the battery reaction. For example, when LiTFSI is used as the electrolyte, the aqueous electrolyte solution may contain 1 mol or more, particularly 5 mol or more, or even 7.5 mol or more of LiTFSI per kg of water. The upper limit is not particularly limited, and may be, for example, 25 mol or less.

[0053] The non-aqueous electrolyte solution generally contains a lithium salt and a non-aqueous solvent. Examples of lithium salts include inorganic lithium salts such as LiPF6, LiBF4, LiClO4, and LiAsF6; and organic lithium salts such as LiCF3SO3, LiN(SO2CF3)2(Li-TFSI), LiN(SO2C2F5)2, and LiC(SO2CF3)3. Examples of non-aqueous solvents include ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), γ-butyrolactone, sulfolane, acetonitrile (AcN), dimethoxymethane, 1,2-dimethoxyethane (DME), 1,3-dimethoxypropane, diethyl ether, tetraethylene glycol dimethyl ether (TEGDME), tetrahydrofuran, 2-methyltetrahydrofuran, dimethyl sulfoxide (DMSO), and mixtures thereof. From the viewpoint of ensuring a high dielectric constant and a low viscosity, the solvent may be a mixture of a cyclic carbonate compound having a high dielectric constant and a high viscosity, such as EC, PC, or BC, and a chain carbonate compound having a low dielectric constant and a low viscosity, such as DMC, DEC, or EMC, or a mixture of EC and DEC. The concentration of the lithium salt in the non-aqueous electrolyte may be, for example, 0.3 to 5M.

[0054] The electrolyte layer may be impregnated with an electrolyte such as the aqueous electrolyte solution described above, and a separator may be used to prevent contact between the positive electrode layer and the negative electrode layer. The separator material is not particularly limited as long as it is a porous film, and examples thereof include resins such as polyethylene (PE), polypropylene (PP), polyester, polyvinyl alcohol, cellulose, and polyamide, among which polyethylene and polypropylene are preferred. The separator may have a single-layer structure or a multi-layer structure. Examples of multi-layer separators include a two-layer structure of PE / PP, or a three-layer structure of PP / PE / PP or PE / PP / PE. The separator may be a nonwoven fabric such as a resin nonwoven fabric or a glass fiber nonwoven fabric.

[0055] [Solid electrolyte layer] The electrolyte layer may be a solid electrolyte layer made of a solid. When the electrolyte layer is a solid electrolyte layer, the solid electrolyte layer contains a solid electrolyte and, if necessary, a binder and the like. The solid electrolyte layer contains, as a solid electrolyte, the solid electrolyte material described above in "A. Solid Electrolyte Material." The solid electrolyte may be used alone or in combination of two or more. When two or more solid electrolytes are used, the two or more solid electrolytes may be mixed, or two or more solid electrolyte layers may be formed to form a multilayer structure. The proportion of the solid electrolyte in the solid electrolyte layer is not particularly limited, but is, for example, 50% by mass or more, and may be in the range of 60% by mass to 100% by mass, 70% by mass to 100% by mass, or even 100% by mass. The solid electrolyte layer may contain less than 1% by mass of electrolytic solution relative to the total amount of the solid electrolyte layer. Examples of the binder include the binders that can be contained in the positive electrode layer described above. The content of the binder in the solid electrolyte layer may be 0% by mass to 10% by mass with respect to the total amount of the solid electrolyte layer.

[0056] The thickness of the electrolyte layer is, for example, 0.1 μm or more and 1000 μm or less, or may be 0.1 μm or more and 500 μm or less, or may be 0.1 μm or more and 100 μm or less.

[0057] The battery of the present disclosure may further include a restraining jig that applies a restraining pressure to the positive electrode layer, the electrolyte layer, and the negative electrode layer in the thickness direction. In particular, when the electrolyte layer is a solid electrolyte layer, the restraining pressure may be applied to form good ion conduction paths and electron conduction paths. The restraining pressure may be, for example, 0.1 MPa or more, 1 MPa or more, or 5 MPa or more. Meanwhile, the restraining pressure may be, for example, 100 MPa or less, 50 MPa or less, or 20 MPa or less.

[0058] [battery] The type of battery in the present disclosure is not particularly limited, but is typically a lithium-ion battery. Furthermore, the battery in the present disclosure may be a liquid battery whose electrolyte layer contains an electrolytic solution, or a solid battery whose electrolyte layer contains a solid electrolyte. The solid battery may be a semi-solid battery or an all-solid-state battery. In the present disclosure, a semi-solid battery is a battery whose electrolyte layer contains an inorganic solid electrolyte and a liquid component (e.g., a solvent and an electrolytic solution). In the present disclosure, an all-solid-state battery is a battery whose electrolyte layer contains only an inorganic solid electrolyte as the electrolyte. Furthermore, the battery in the present disclosure may be a primary battery or a secondary battery, but a secondary battery is particularly preferred. This is because it can be repeatedly charged and discharged and is useful, for example, as an on-board battery. The shape of the battery is not particularly limited, and may be, for example, a coin type, a cylindrical type, a square type, a sheet type, a button type, a flat type, or a laminate type.

[0059] Examples of uses of the battery include power sources for vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), electric vehicles (BEVs), gasoline-powered vehicles, and diesel-powered vehicles. In particular, the battery may be used as a driving power source for hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), or electric vehicles (BEVs). The battery may also be used as a power source for mobile objects other than vehicles (for example, trains, ships, and aircraft), and as a power source for electrical appliances such as information processing devices.

[0060] The present disclosure is not limited to the above-described embodiments. The above-described embodiments are merely examples, and any configuration that is substantially identical to the technical idea described in the claims of the present disclosure and that provides similar effects is included within the technical scope of the present disclosure. [Example]

[0061] [Examples 1 to 3] (Preparation of solid electrolyte materials) <PMTFSI-Li+SN+SiO2> In an Ar atmosphere glove box, succinonitrile and PMTFSI-Li (Polykey, Spain) as an electrolyte polymer were weighed out in a molar ratio of SN:PMTFSI-Li = 4:1, and dissolved in acetonitrile (Sigma-Aldrich) by stirring for 24 hours. Furthermore, SiO2 (Sigma-Aldrich, average particle size 0.1 μm to 0.2 μm) as an inorganic filler was added to the resulting solution in amounts of 1 mass% (Example 1), 5 mass% (Example 2), and 10 mass% (Example 3) relative to the total amount of the resulting solid electrolyte material, and the mixture was stirred for 12 hours. The resulting solution was placed on a hot plate at 50°C to volatilize the acetonitrile, and then vacuum dried at 50°C for 6 hours to obtain a solid electrolyte material.

[0062] [Comparative Example 1] <PMTFSI-Li+SN> A solid electrolyte material was obtained in the same manner as in Example 1, except that no inorganic filler was added in the preparation of the solid electrolyte material.

[0063] [Example 4] <PMTFSI-Li+SN+Al2O3> In the preparation of the solid electrolyte material, a solid electrolyte material was obtained in the same manner as in Example 1, except that Al2O3 (manufactured by Sigma-Aldrich, average particle size 0.1 μm to 0.2 μm) was added as the inorganic filler instead of SiO2 so as to be 5 mass % relative to the total amount of the obtained solid electrolyte material.

[0064] [Example 5] <PSTFSI-Li+SN+SiO2> A solid electrolyte material was obtained in the same manner as in Example 1, except that in the preparation of the solid electrolyte material, PSTFSI-Li was used instead of PMTFSI-Li as the electrolyte polymer, and SiO2 (manufactured by Sigma-Aldrich, average particle size 0.1 μm to 0.2 μm) was added as the inorganic filler so as to be 5 mass % relative to the total amount of the obtained solid electrolyte material.

[0065] (Measurement of ionic conductivity) Each of the solid electrolyte materials obtained in Examples 1 to 5 and Comparative Example 1 was sealed in a glass cell equipped with platinum electrodes and having a known cell constant in an Ar glove box to prepare a cell. The fabricated cell was left to stand in a thermostatic chamber at 70°C for 2 hours, then cooled to 25°C. The AC impedance of the cell was measured under conditions of an applied voltage of 10 mV and an AC frequency of 1 Hz-1 MHz. The ionic conductivity of the solid electrolyte material was calculated from the impedance results and used as the initial ionic conductivity. Furthermore, after leaving the cell to stand in a thermostatic chamber at 25°C for 30 days, the AC impedance of the cell was measured again under conditions of an applied voltage of 10 mV and an AC frequency of 1 Hz to 1 MHz, and the ionic conductivity of the solid electrolyte material was calculated from the impedance results, and this was used as the ionic conductivity after 30 days. The ionic conductivity maintenance rate was calculated from the ionic conductivity after 30 days relative to the initial ionic conductivity. Ion conductivity retention rate (%) = (ion conductivity after 30 days ÷ initial ion conductivity) × 100 The results are shown in Table 1.

[0066] [Table 1]

[0067] It can be seen that Examples 1 to 5, in which an inorganic filler was added, had a higher ionic conductivity maintenance rate after 30 days than Comparative Example 1, in which an inorganic filler was not added. Therefore, according to the present disclosure, even when the solid electrolyte material is stored for a long period of time, such as 30 days, in a low-temperature environment of 25°C, the decrease in ionic conductivity of the solid electrolyte material can be suppressed. [Explanation of symbols]

[0068] 1...Positive electrode layer 2...Anode layer 3...electrolyte layer 4...Positive electrode current collector 5...Negative electrode current collector 10...battery

Claims

1. The polymer electrolyte includes an inorganic filler and succinonitrile, The solid electrolyte material is characterized in that the polymer electrolyte contains an anionic polymer.

2. The solid electrolyte material according to claim 1 , wherein the inorganic filler is present in an amount of 1 mass % or more and 10 mass % or less relative to the total amount of the solid electrolyte material.

3. The inorganic filler is SiO ２ The solid electrolyte material according to claim 1,

4. The inorganic filler is Al ２ O ３ The solid electrolyte material according to claim 1,

5. 2. The solid electrolyte material according to claim 1, wherein the polymer electrolyte contains at least one of a bis(fluorosulfonyl)imide anion and a bis(trifluoromethanesulfonyl)imide anion.

6. 2. The solid electrolyte material according to claim 1, wherein the polymer electrolyte contains at least one of poly((trifluoromethane)sulfonimide lithium methacrylate) and poly(styrene-4-sulfonyltrifluoromethylsulfonyl)imide lithium.

7. A battery having a positive electrode layer, a negative electrode layer, and an electrolyte layer, the negative electrode layer contains, as a negative electrode active material, at least one of Li simple substance and a Li alloy, the electrolyte layer includes a solid electrolyte and an electrolyte solution, A battery, wherein the solid electrolyte is the solid electrolyte material according to any one of claims 1 to 6.

8. An all-solid-state battery having a positive electrode layer, a negative electrode layer, and a solid electrolyte layer, the negative electrode layer contains, as a negative electrode active material, at least one of Li simple substance and a Li alloy, the solid electrolyte layer includes a solid electrolyte, An all-solid-state battery, wherein the solid electrolyte is the solid electrolyte material according to any one of claims 1 to 6.

Images