Solid electrolyte material and battery using same

Abstract

This solid electrolyte material includes Li, Sn, M1, and F. M1 is at least one element selected from the group consisting of Al, Y, Zr, Ti, and Mg. A battery 1000 comprises a positive electrode 201, a negative electrode 203, and a separator layer 202 provided between the positive electrode 201 and the negative electrode 203. At least one component selected from the group consisting of the positive electrode 201, the negative electrode 203, and the separator layer 202 contains the solid electrolyte material.

Description

Solid electrolyte material and battery using the same

[0001] The present disclosure relates to a solid electrolyte material and a battery using the same.

[0002] Fluoride solid electrolyte materials generally have excellent oxidation resistance. Patent Document 1 discloses LiBF4 as a fluoride solid electrolyte material.

[0003] JP 2008-277170 A

[0004] An object of the present disclosure is to provide a fluoride solid electrolyte material with improved lithium ion conductivity.

[0005] The solid electrolyte material of the present disclosure contains Li, Sn, M1, and F, where M1 is at least one selected from the group consisting of Al, Y, Zr, Ti, and Mg.

[0006] The present disclosure provides fluoride solid electrolyte materials with enhanced lithium ion conductivity.

[0007] FIG. 1 shows a cross-sectional view of a battery 1000, which is a first example of a battery according to the second embodiment. FIG. 2 shows a cross-sectional view of a battery 2000, which is a second example of a battery according to the second embodiment. FIG. 3 shows a cross-sectional view of a battery 3000, which is a third example of a battery according to the second embodiment. FIG. 4 shows a schematic diagram of a pressure forming die 500 used to evaluate the ionic conductivity of a solid electrolyte material. FIG. 5 is a graph showing a Cole-Cole plot obtained by measuring the impedance of the solid electrolyte material according to Example 1. FIG. 6 is a graph showing the initial discharge characteristics of the battery according to Example 1.

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0009] First Embodiment A solid electrolyte material according to a first embodiment contains Li, Sn, M1, and F. Here, M1 is at least one selected from the group consisting of Al, Y, Zr, Ti, and Mg.

[0010] With the above configuration, the solid electrolyte material according to the first embodiment has improved lithium ion conductivity.

[0011] The solid electrolyte material according to the first embodiment is a fluoride solid electrolyte material containing F. Therefore, the solid electrolyte material according to the first embodiment can have high oxidation resistance. This is because F has a high oxidation-reduction potential. On the other hand, F has a high electronegativity, so it bonds relatively strongly with Li. As a result, the lithium ion conductivity of fluoride solid electrolyte materials generally tends to be low. For example, LiBF4 disclosed in Patent Document 1 has a 6.67×10 -9 It has a low ionic conductivity of 100 S / cm.

[0012] The solid electrolyte material according to the first embodiment can improve the lithium ion conductivity in a fluoride solid electrolyte material. The solid electrolyte material according to the first embodiment can have, for example, a practical lithium ion conductivity, for example, a high lithium ion conductivity. Here, in this specification, a high lithium ion conductivity means, for example, a lithium ion conductivity of 8×10 or more at around room temperature (for example, 25° C.). -9 The solid electrolyte material according to the first embodiment has a specific resistance of, for example, 8×10 -9 The ionic conductivity may be 100 S / cm or more.

[0013] The solid electrolyte material according to the first embodiment desirably contains substantially no sulfur. The fact that the solid electrolyte material according to the first embodiment is substantially free of sulfur means that the solid electrolyte material does not contain sulfur as a constituent element, except for sulfur that is inevitably mixed in as an impurity. In this case, the amount of sulfur mixed in the solid electrolyte material as an impurity is, for example, 1 mol % or less. It is more desirable that the solid electrolyte material according to the first embodiment does not contain sulfur. A sulfur-free solid electrolyte material does not generate hydrogen sulfide even when exposed to the atmosphere, and is therefore highly safe.

[0014] In order to increase the lithium ion conductivity of the solid electrolyte material, the solid electrolyte material according to the first embodiment may further contain anions other than F. Examples of such anions are Cl, Br, I, O, S, or Se.

[0015] The solid electrolyte material according to the first embodiment may consist essentially of Li, Sn, M1, and F. Here, "the solid electrolyte material according to the first embodiment consists essentially of Li, Sn, M1, and F" means that the molar ratio of the total amount of substance of Li, Sn, M1, and F to the total amount of substance of all elements constituting the solid electrolyte material according to the first embodiment is 90% or more. As an example, the molar ratio may be 95% or more. The solid electrolyte material according to the first embodiment may consist only of Li, Sn, M1, and F.

[0016] The solid electrolyte material according to the first embodiment may contain elements that are inevitably mixed in. Examples of such elements are hydrogen, oxygen, or nitrogen. Such elements may be present in the raw material powder of the solid electrolyte material or in the atmosphere used for producing or storing the solid electrolyte material. In the solid electrolyte material according to the first embodiment, the amount of such elements that are inevitably mixed in is, for example, 1 mol % or less.

[0017] In order to enhance the lithium ion conductivity of the solid electrolyte material, M1 may contain at least one selected from the group consisting of Al and Y in the solid electrolyte material according to the first embodiment.

[0018] In order to further increase the lithium ion conductivity of the solid electrolyte material, the ratio of the amount of substance of Li to the total amount of substances of cations other than Li may be 1.7 or more and 4.2 or less.

[0019] The solid electrolyte material according to the first embodiment may be represented by the following composition formula (1-1): Li6-(4-a1)b1(Sn 1-a1 M1 a1 ) b1 F6 Formula (1-1) where a1 and b1 satisfy the relational expressions 0<a1<1 and 0<b1≦1.5. In composition formula (1-1), M1 is at least one selected from the group consisting of Al and Y, which are trivalent cations.

[0020] Since the solid electrolyte material according to the first embodiment is represented by the composition formula (1-1), the solid electrolyte material according to the first embodiment can further improve the ionic conductivity.

[0021] In order to enhance the ionic conductivity of the solid electrolyte material, the solid electrolyte material according to the first embodiment may contain a crystalline phase represented by composition formula (1-1).

[0022] The solid electrolyte material according to the first embodiment may further contain oxygen (O). In this case, the solid electrolyte material according to the first embodiment may be represented by the following composition formula (1-2): Li6-(4-a1)b1(Sn 1-a1 M1 a1 ) b1 F 6-2d1 O d1 Formula (1-2) Here, a1, b1, and M1 in composition formula (1-2) are the same as a1, b1, and M1 in composition formula (1-1), respectively. In composition formula (1-2), d1 satisfies the relational expression 0<d1<3.

[0023] When the solid electrolyte material according to the first embodiment is represented by composition formula (1-2), the ionic conductivity of the solid electrolyte material according to the first embodiment can be further improved, similarly to the case where the solid electrolyte material is represented by composition formula (1-1).

[0024] In order to enhance the ionic conductivity of the solid electrolyte material, the solid electrolyte material according to the first embodiment may contain a crystalline phase represented by composition formula (1-2).

[0025] In order to enhance the ionic conductivity of the solid electrolyte material, a1 in the composition formula (1-1) and the composition formula (1-2) may satisfy the relational expression 0.01≦a1≦0.99.

[0026] In order to enhance the ionic conductivity of the solid electrolyte material, a1 in the composition formula (1-1) and the composition formula (1-2) may satisfy the relational expression 0.01≦a1≦0.7.

[0027] In order to enhance the ionic conductivity of the solid electrolyte material, b1 in the composition formula (1-1) and the composition formula (1-2) may satisfy the relational expression 0.8≦b1≦1.2.

[0028] In order to enhance the ionic conductivity of the solid electrolyte material, M1 in the composition formula (1-1) and the composition formula (1-2) may be Al. For example, in the composition formula (1-1) and the composition formula (1-2), M1 may be Al and a1 may satisfy the relational expression of 0.01≦a1≦0.99. With this configuration, the solid electrolyte material according to the first embodiment can further enhance the ionic conductivity. In order to further enhance the ionic conductivity of the solid electrolyte material, M1 in the composition formula (1-1) and the composition formula (1-2) may be Al and a1 may satisfy the relational expression of 0.01≦a1≦0.7.

[0029] In order to enhance the ionic conductivity of the solid electrolyte material, the solid electrolyte material according to the first embodiment may contain Li, Sn, Al, M2, and F, where M2 is at least one selected from the group consisting of Y, Zr, Ti, and Mg.

[0030] The solid electrolyte material according to the first embodiment may be represented by the following composition formula (2-1): Li6-(4-a2-(4-c2)x2)b2(Sn 1-a2-x2 Al a2 M2 x2 ) b2 F6 Formula (2-1) where a2, x2, and b2 satisfy the relational expressions 0<a2<1, 0<x2<1, 0<a2+x2<1, and 0<b2≦1.5. Also, c2 is the valence of M2.

[0031] In order to enhance the ionic conductivity of the solid electrolyte material, the solid electrolyte material according to the first embodiment may contain a crystalline phase represented by composition formula (2-1).

[0032] The solid electrolyte material according to the first embodiment may contain oxygen (O) as described above. In this case, the solid electrolyte material according to the first embodiment may be represented by the following composition formula (2-2): Li6-(4-a2-(4-c2)x2)b2(Sn 1-a2-x2 Al a2 M2 x2 ) b2 F 6-2d2 O d2Formula (2-2) where a2, b2, c2, and M2 in composition formula (2-2) are the same as a2, b2, c2, and M2 in composition formula (2-1), respectively. In composition formula (2-2), d2 satisfies the relational expression 0<d2<3.

[0033] In order to enhance the ionic conductivity of the solid electrolyte material, the solid electrolyte material according to the first embodiment may contain a crystalline phase represented by composition formula (2-2).

[0034] An effective means for improving lithium ion conductivity is, for example, introducing distortion into the crystal structure by dissolving different cations. Ti and Zr are tetravalent like Sn, Y is trivalent like Al, and Mg has an ionic radius close to that of Sn. Therefore, in a solid electrolyte material containing Li, Sn, Al, and F, Y, Zr, Ti, and Mg are each relatively easily dissolved, and improvement in lithium ion conductivity can be expected. A solid electrolyte material containing such a crystalline phase has high ionic conductivity.

[0035] In order to enhance the ionic conductivity of the solid electrolyte material, a2 in the composition formulas (2-1) and (2-2) may satisfy the relational expression 0.01≦a2≦0.99.

[0036] In order to enhance the ionic conductivity of the solid electrolyte material, a2 in the composition formulas (2-1) and (2-2) may satisfy the relational expression 0.01≦a2≦0.7.

[0037] In order to enhance the ionic conductivity of the solid electrolyte material, b2 in the composition formulas (2-1) and (2-2) may satisfy the relational expression 0.8≦b2≦1.2.

[0038] The solid electrolyte material according to the first embodiment may be crystalline or amorphous.

[0039] The shape of the solid electrolyte material according to the first embodiment is not limited. Examples of the shape include a needle shape, a sphere shape, or an oval sphere shape. The solid electrolyte material according to the first embodiment may be in the form of particles. The solid electrolyte material according to the first embodiment may be formed into a pellet or plate shape.

[0040] When the solid electrolyte material according to the first embodiment has a particulate (e.g., spherical) shape, the solid electrolyte material may have a median diameter of 0.1 μm or more and 100 μm or less. The median diameter refers to the particle size at which the cumulative volume in the volume-based particle size distribution is 50%. The volume-based particle size distribution is measured, for example, by a laser diffraction measurement device or an image analysis device.

[0041] The solid electrolyte material according to the first embodiment may have a median diameter of 0.5 μm or more and 10 μm or less. This allows the solid electrolyte material to have higher ionic conductivity. Furthermore, in this case, the solid electrolyte material according to the first embodiment and other materials such as active materials are well dispersed.

[0042] <Method for Producing Solid Electrolyte Material> The solid electrolyte material according to the first embodiment can be produced, for example, by the following method.

[0043] For example, raw material powders of a plurality of halides are mixed together to obtain a desired composition.

[0044] As an example, the desired composition is Li 2.7 Sn 0.3 Al 0.7 In the case of F, LiF, SnF, and AlF are mixed in a molar ratio of about 2.7:0.3:0.7. The raw material powders may be mixed in a pre-adjusted molar ratio to offset composition changes that may occur in the synthesis process.

[0045] The raw material powders are reacted with each other mechanochemically (i.e., using a mechanochemical milling method) in a mixing device such as a planetary ball mill to obtain a reactant. The reactant may be fired in a vacuum or in an inert atmosphere. Alternatively, a mixture of the raw material powders may be fired in a vacuum or in an inert atmosphere to obtain a reactant. The firing is preferably carried out, for example, at a temperature of 100°C or higher and 300°C or lower for one hour or longer. In order to suppress compositional changes during firing, the raw material powders are preferably fired in a sealed container such as a quartz tube.

[0046] By these methods, the solid electrolyte material according to the first embodiment can be obtained.

[0047] The composition of the solid electrolyte material can be determined by, for example, ICP emission spectroscopy, ion chromatography, inert gas fusion-infrared absorption spectroscopy, or EPMA (Electron Probe Micro Analyzer). For example, the compositions of Li, Sn, and M1 can be determined by ICP emission spectroscopy, and the composition of F can be determined by ion chromatography.

[0048] Second Embodiment A second embodiment will be described below, and the matters described in the first embodiment will be omitted as appropriate.

[0049] The battery according to the second embodiment includes a positive electrode, a negative electrode, and a separator layer. The separator layer is disposed between the positive electrode and the negative electrode.

[0050] At least one selected from the group consisting of the positive electrode, the negative electrode, and the separator layer contains the solid electrolyte material according to the first embodiment.

[0051] The battery according to the second embodiment contains the solid electrolyte material according to the first embodiment, and therefore has excellent charge / discharge characteristics.

[0052] The battery according to the second embodiment may be an all-solid-state battery using a solid electrolyte as the electrolyte, or may be a liquid battery using an electrolytic solution as the electrolyte. The all-solid-state battery may be a primary battery or a secondary battery.

[0053] 1 shows a cross-sectional view of a battery 1000, which is a first example of a battery according to the second embodiment. This first example battery 1000 is a configuration example in which the separator layer is an electrolyte layer formed of an electrolyte material. In the battery 1000, the electrolyte layer is, for example, a solid electrolyte layer, i.e., the battery 1000 is, for example, an all-solid-state battery.

[0054] The battery 1000 of the first example includes a positive electrode 201, an electrolyte layer 202, and a negative electrode 203. The electrolyte layer 202 is provided between the positive electrode 201 and the negative electrode 203.

[0055] The positive electrode 201 contains a positive electrode active material 204 and a solid electrolyte 100 .

[0056] The electrolyte layer 202 contains an electrolyte material.

[0057] The negative electrode 203 contains a negative electrode active material 205 and a solid electrolyte 100 .

[0058] The solid electrolyte 100 includes, for example, the solid electrolyte material according to the first embodiment. The solid electrolyte 100 may be particles containing the solid electrolyte material according to the first embodiment as a main component. Particles containing the solid electrolyte material according to the first embodiment as a main component refer to particles in which the component contained most abundantly in terms of molar ratio is the solid electrolyte material according to the first embodiment. The solid electrolyte 100 may be particles made of the solid electrolyte material according to the first embodiment.

[0059] The positive electrode 201 contains a material capable of absorbing and releasing metal ions (e.g., lithium ions). The material is, for example, a positive electrode active material 204.

[0060] Examples of the positive electrode active material 204 include a lithium-containing transition metal oxide, a transition metal fluoride, a polyanion, a fluorinated polyanion material, a transition metal sulfide, a transition metal oxyfluoride, a transition metal oxysulfide, or a transition metal oxynitride. Examples of the lithium-containing transition metal oxide include Li(Ni,Co,Mn)O, Li(Ni,Co,Al)O, or LiCoO.

[0061] In the present disclosure, "(A, B, C)" means "at least one selected from the group consisting of A, B, and C."

[0062] The shape of the positive electrode active material 204 is not limited to a specific shape. The positive electrode active material 204 may be particles. The positive electrode active material 204 may have a median diameter of 0.1 μm or more and 100 μm or less. When the positive electrode active material 204 has a median diameter of 0.1 μm or more, the positive electrode active material 204 and the solid electrolyte 100 can be well dispersed in the positive electrode 201. This improves the charge / discharge characteristics of the battery 1000. When the positive electrode active material 204 has a median diameter of 100 μm or less, the lithium diffusion rate within the positive electrode active material 204 improves. This allows the battery 1000 to operate at a high output.

[0063] The positive electrode active material 204 may have a larger median diameter than the solid electrolyte 100. This allows the positive electrode active material 204 and the solid electrolyte 100 to be dispersed well in the positive electrode 201.

[0064] In order to improve the energy density and output of the battery 1000, in the positive electrode 201, the ratio of the volume of the positive electrode active material 204 to the sum of the volume of the positive electrode active material 204 and the volume of the solid electrolyte 100 may be 0.30 or more and 0.95 or less.

[0065] A coating layer may be formed on at least a portion of the surface of the positive electrode active material 204. The coating layer may be formed on the surface of the positive electrode active material 204, for example, before mixing with the conductive additive and the binder. Examples of coating materials included in the coating layer include a sulfide solid electrolyte, an oxide solid electrolyte, or a halide solid electrolyte. When the solid electrolyte 100 contains a sulfide solid electrolyte, the coating material may contain the solid electrolyte material according to the first embodiment to suppress oxidative decomposition of the sulfide solid electrolyte. When the solid electrolyte 100 contains the solid electrolyte material according to the first embodiment, the coating material may contain an oxide solid electrolyte to suppress oxidative decomposition of the solid electrolyte material. Lithium niobate, which has excellent stability at high potentials, may be used as the oxide solid electrolyte. By suppressing oxidative decomposition, an increase in overvoltage of the battery 1000 can be suppressed.

[0066] To improve the energy density and output of the battery 1000, the positive electrode 201 may have a thickness of 10 μm or more and 500 μm or less.

[0067] The electrolyte layer 202 contains an electrolyte material. The electrolyte material is, for example, a solid electrolyte material. The solid electrolyte material may include the solid electrolyte material according to the first embodiment. The electrolyte layer 202 may be a solid electrolyte layer.

[0068] The electrolyte layer 202 may contain 50 mass % or more of the solid electrolyte material according to the first embodiment. The electrolyte layer 202 may contain 70 mass % or more of the solid electrolyte material according to the first embodiment. The electrolyte layer 202 may contain 90 mass % or more of the solid electrolyte material according to the first embodiment. The electrolyte layer 202 may be made of only the solid electrolyte material according to the first embodiment.

[0069] Hereinafter, the solid electrolyte material according to the first embodiment will be referred to as a first solid electrolyte material, and a solid electrolyte material different from the first solid electrolyte material will be referred to as a second solid electrolyte material.

[0070] The electrolyte layer 202 may contain not only the first solid electrolyte material but also the second solid electrolyte material. In the electrolyte layer 202, the first solid electrolyte material and the second solid electrolyte material may be uniformly dispersed.

[0071] The electrolyte layer 202 may be made of only the second solid electrolyte material.

[0072] The electrolyte layer 202 may have a thickness of 1 μm or more and 1000 μm or less. When the electrolyte layer 202 has a thickness of 1 μm or more, the cathode 201 and the anode 203 are less likely to short-circuit. When the electrolyte layer 202 has a thickness of 1000 μm or less, the battery 1000 can operate at high power.

[0073] Examples of the second solid electrolyte material are LiMgX, LiFeX, Li(Al,Ga,In)X, Li(Al,Ga,In)X, or LiI, where X is at least one selected from the group consisting of F, Cl, Br, and I.

[0074] To improve the energy density and power output of the battery 1000, the electrolyte layer 202 may have a thickness of 1 μm or more and 1000 μm or less.

[0075] The negative electrode 203 contains a material capable of absorbing and releasing metal ions (e.g., lithium ions). The material is, for example, a negative electrode active material 205.

[0076] Examples of the negative electrode active material 205 include a metal material, a carbon material, an oxide, a nitride, a tin compound, or a silicon compound. The metal material may be a simple metal or an alloy. An example of the metal material is lithium metal or a lithium alloy. Examples of the carbon material are natural graphite, coke, partially graphitized carbon, carbon fiber, spherical carbon, artificial graphite, or amorphous carbon. From the viewpoint of capacity density, suitable examples of the negative electrode active material are silicon (i.e., Si), tin (i.e., Sn), a silicon compound, or a tin compound.

[0077] The anode active material 205 may be selected taking into consideration the reduction resistance of the solid electrolyte material contained in the anode 203. For example, when the anode 203 contains a first solid electrolyte material, the anode active material 205 may be a material capable of absorbing and releasing lithium ions at 0.27 V or more relative to lithium. Examples of such anode active materials include titanium oxide, indium metal, or a lithium alloy. An example of titanium oxide is Li4Ti5O 12 , LiTiO, or TiO. By using the above-mentioned negative electrode active material, it is possible to suppress the reductive decomposition of the first solid electrolyte material contained in the negative electrode 203. As a result, it is possible to improve the charge / discharge efficiency of the battery 1000.

[0078] The shape of the negative electrode active material 205 is not limited to a specific shape. The negative electrode active material 205 may be particles. The negative electrode active material 205 may have a median diameter of 0.1 μm or more and 100 μm or less. When the negative electrode active material 205 has a median diameter of 0.1 μm or more, the negative electrode active material 205 and the solid electrolyte 100 can be well dispersed in the negative electrode 203. This improves the charge / discharge characteristics of the battery 1000. When the negative electrode active material 205 has a median diameter of 100 μm or less, the lithium diffusion rate within the negative electrode active material 205 improves. This allows the battery 1000 to operate at high power.

[0079] The negative electrode active material 205 may have a larger median diameter than the solid electrolyte 100. This allows the negative electrode active material 205 and the solid electrolyte 100 to be dispersed well in the negative electrode 203.

[0080] In order to improve the energy density and output of the battery 1000, in the negative electrode 203, the ratio of the volume of the negative electrode active material 205 to the sum of the volume of the negative electrode active material 205 and the volume of the solid electrolyte 100 may be 0.30 or more and 0.95 or less.

[0081] To improve the energy density and output of the battery 1000, the negative electrode 203 may have a thickness of 10 μm or more and 500 μm or less.

[0082] At least one selected from the group consisting of the positive electrode 201, the electrolyte layer 202, and the negative electrode 203 may contain a second solid electrolyte material for the purpose of increasing ionic conductivity, chemical stability, and electrochemical stability.

[0083] The second solid electrolyte material may be a sulfide solid electrolyte.

[0084] Examples of sulfide solid electrolytes include Li2S-P2S5, Li2S-SiS2, Li2S-B2S3, Li2S-GeS2, and Li 3.25 Ge 0.25 P 0.75 S4, or Li 10 GeP2S 12 is.

[0085] When the electrolyte layer 202 contains a first solid electrolyte material, the anode 203 may contain a sulfide solid electrolyte to suppress reductive decomposition of the solid electrolyte material. The electrochemically stable sulfide solid electrolyte covers the anode active material, thereby suppressing contact between the first solid electrolyte material and the anode active material. As a result, the internal resistance of the battery 1000 can be reduced.

[0086] The second solid electrolyte material may be an oxide solid electrolyte.

[0087] Examples of oxide solid electrolytes include: (i) NASICON-type solid electrolytes such as LiTi2(PO4)3 or its elemental substitutions; (ii) perovskite-type solid electrolytes such as (LaLi)TiO3; (iii) Li 14 ZnGeO 16LISICON-type solid electrolytes such as LiSiO, LiGeO or elemental substitutions thereof; (iv) LiLaZrO 12 or an element-substituted product thereof, or (v) a garnet-type solid electrolyte such as Li3PO4 or an N-substituted product thereof.

[0088] As mentioned above, the second solid electrolyte material may be a halide solid electrolyte.

[0089] Examples of halide solid electrolytes are LiMgX, LiFeX, Li(Al,Ga,In)X, Li(Al,Ga,In)X, or LiI, where X is at least one selected from the group consisting of F, Cl, Br, and I.

[0090] Other examples of halide solid electrolytes include Li a Me b Y c X6. Here, a, b, and c satisfy the relationship a+mb+3c=6 and c>0. Me is at least one selected from the group consisting of metal elements and metalloid elements other than Li and Y. X is at least one selected from the group consisting of F, Cl, Br, and I. m represents the valence of Me. "Metalloid elements" are B, Si, Ge, As, Sb, and Te. "Metal elements" are all elements included in Groups 1 to 12 of the periodic table (excluding hydrogen) and all elements included in Groups 13 to 16 of the periodic table (excluding B, Si, Ge, As, Sb, Te, C, N, P, O, S, and Se).

[0091] In order to improve the ionic conductivity of the halide solid electrolyte, Me may be at least one selected from the group consisting of Mg, Ca, Sr, Ba, Zn, Sc, Al, Ga, Bi, Zr, Hf, Ti, Sn, Ta, and Nb.

[0092] The halide solid electrolyte may be Li3YCl6 or Li3YBr6.

[0093] The second solid electrolyte material may be an organic polymer solid electrolyte.

[0094] Examples of organic polymer solid electrolytes are compounds of polymer compounds and lithium salts.

[0095] The polymer compound may have an ethylene oxide structure. A polymer compound having an ethylene oxide structure can contain a large amount of lithium salt, and therefore can further increase ionic conductivity.

[0096] Examples of lithium salts include LiPF, LiBF, LiSbF, LiAsF, LiSOCF, LiN(SOCF), LiN(SOCF), LiN(SOCF)(SOCF), or LiC(SOCF). One lithium salt selected from these may be used alone. Alternatively, a mixture of two or more lithium salts selected from these may be used.

[0097] At least one selected from the group consisting of the positive electrode 201, the electrolyte layer 202, and the negative electrode 203 may contain a non-aqueous electrolyte solution, a gel electrolyte, or an ionic liquid to facilitate the exchange of lithium ions and improve the output characteristics of the battery.

[0098] The non-aqueous electrolyte contains a non-aqueous solvent and a lithium salt dissolved in the non-aqueous solvent.

[0099] Examples of non-aqueous solvents are cyclic carbonate ester solvents, chain carbonate ester solvents, cyclic ether solvents, chain ether solvents, cyclic ester solvents, chain ester solvents, or fluorine-containing solvents. Examples of cyclic carbonate ester solvents are ethylene carbonate, propylene carbonate, or butylene carbonate. Examples of chain carbonate ester solvents are dimethyl carbonate, ethyl methyl carbonate, or diethyl carbonate. Examples of cyclic ether solvents are tetrahydrofuran, 1,4-dioxane, or 1,3-dioxolane. Examples of chain ether solvents are 1,2-dimethoxyethane or 1,2-diethoxyethane. An example of a cyclic ester solvent is γ-butyrolactone. An example of a chain ester solvent is methyl acetate. Examples of fluorine-containing solvents are fluoroethylene carbonate, methyl fluoropropionate, fluorobenzene, fluoroethyl methyl carbonate, or fluorodimethylene carbonate. One non-aqueous solvent selected from these may be used alone, or two or more non-aqueous solvents selected from these may be used in combination.

[0100] Examples of lithium salts include LiPF, LiBF, LiSbF, LiAsF, LiSOCF, LiN(SOCF), LiN(SOCF), LiN(SOCF)(SOCF), or LiC(SOCF). A single lithium salt selected from these may be used alone. Alternatively, a mixture of two or more lithium salts selected from these may be used. The concentration of the lithium salt is, for example, in the range of 0.5 mol / L or more and 2 mol / L or less.

[0101] The gel electrolyte may be a polymer material impregnated with a non-aqueous electrolyte, such as polyethylene oxide, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, or a polymer having an ethylene oxide bond.

[0102] Examples of cations contained in the ionic liquid are: (i) aliphatic chain quaternary salts such as tetraalkylammonium or tetraalkylphosphonium; (ii) aliphatic cyclic ammoniums such as pyrrolidiniums, morpholiniums, imidazoliniums, tetrahydropyrimidiniums, piperaziniums, or piperidiniums; or (iii) nitrogen-containing heterocyclic aromatic cations such as pyridiniums or imidazoliums.

[0103] An example of an anion contained in an ionic liquid is PF6 - , BF4 - , SbF 6- - , AsF6 - , SO3CF3 - , N(SO2CF3)2 - , N(SO2C2F5)2 - , N(SO2CF3)(SO2C4F9) - , or C(SO2CF3)3 - is.

[0104] The ionic liquid may contain a lithium salt.

[0105] At least one selected from the group consisting of the positive electrode 201, the electrolyte layer 202, and the negative electrode 203 may contain a binder to improve adhesion between particles.

[0106] Examples of binders include polyvinylidene fluoride, polytetrafluoroethylene, polyethylene, polypropylene, aramid resin, polyamide, polyimide, polyamideimide, polyacrylonitrile, polyacrylic acid, polymethyl ester of acrylic acid, polyethyl ester of acrylic acid, polyhexyl ester of acrylic acid, polymethacrylic acid, polymethyl ester of methacrylic acid, polyethyl ester of methacrylic acid, polyhexyl ester of methacrylic acid, polyvinyl acetate, polyvinylpyrrolidone, polyether, polyethersulfone, hexafluoropolypropylene, styrene-butadiene rubber, and carboxymethyl cellulose. Copolymers can also be used as binders. Examples of such binders include copolymers of two or more materials selected from the group consisting of tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoroalkyl vinyl ether, vinylidene fluoride, chlorotrifluoroethylene, ethylene, propylene, pentafluoropropylene, fluoromethyl vinyl ether, acrylic acid, and hexadiene. Mixtures of two or more materials selected from these may also be used as binders.

[0107] At least one selected from the positive electrode 201 and the negative electrode 203 may contain a conductive additive to improve electronic conductivity.

[0108] Examples of the conductive additive include: (i) graphites such as natural graphite or artificial graphite, (ii) carbon blacks such as acetylene black or ketjen black, (iii) conductive fibers such as carbon fiber or metal fiber, (iv) carbon fluoride, (v) metal powders such as aluminum, (vi) conductive whiskers such as zinc oxide or potassium titanate, (vii) conductive metal oxides such as titanium oxide, or (viii) conductive polymer compounds such as polyaniline, polypyrrole, or polythiophene. To reduce costs, the conductive additives (i) or (ii) above may be used.

[0109] FIG. 2 shows a cross-sectional view of a battery 2000, which is a second example of the battery according to the second embodiment. The battery 2000 of the second example has a configuration in which an electrolyte layer 301 is provided instead of the electrolyte layer 202 in the battery 1000 of the first example. The electrolyte layer 301 includes a first solid electrolyte layer 302 and a second solid electrolyte layer 303. The first solid electrolyte layer 302 and the second solid electrolyte layer 303 are stacked along the stacking direction of the battery 2000. The first solid electrolyte layer 302 is disposed between the positive electrode 201 and the second solid electrolyte layer 303. The second solid electrolyte layer 303 is disposed between the first solid electrolyte layer 302 and the negative electrode 203. The battery 2000 may include the positive electrode 201, the first solid electrolyte layer 302, the second solid electrolyte layer 303, and the negative electrode 203, in this order.

[0110] Here, the solid electrolyte material contained in the second solid electrolyte layer 303 may have a lower reduction potential than the solid electrolyte material contained in the first solid electrolyte layer 302. This allows the solid electrolyte material contained in the first solid electrolyte layer 302 to be used without being reduced. As a result, the charge / discharge efficiency of the battery 2000 can be improved. For example, when the first solid electrolyte layer 302 contains the first solid electrolyte material, the second solid electrolyte layer 303 may contain a sulfide solid electrolyte to suppress reductive decomposition of the solid electrolyte material. This allows the charge / discharge efficiency of the battery 2000 to be improved. The first solid electrolyte layer 302 may contain the first solid electrolyte material. Since the first solid electrolyte material has high oxidation resistance, a battery with excellent charge / discharge characteristics can be realized.

[0111] The battery according to the second embodiment may be a liquid battery, that is, the separator layer may be a separator used in known liquid batteries.

[0112] FIG. 3 shows a cross-sectional view of a battery 3000, which is a third example of the battery according to the second embodiment. The battery 3000 is an example of a liquid battery. In FIG. 3, components having the same functions as those shown in FIG. 1 are denoted by the same reference numerals. The battery 3000 includes a positive electrode 201, a negative electrode 203, an electrolyte 401, a separator 402, and an exterior 403. A current collector 404 is attached to the positive electrode 201. A current collector 405 is attached to the negative electrode 203. The separator 402 is disposed between the positive electrode 201 and the negative electrode 203. The positive electrode 201 and the negative electrode 203 face each other with the separator 402 interposed therebetween. The positive electrode 201, the negative electrode 203, the separator 402, and the electrolyte 401 are housed in the exterior 403. The electrolytic solution 401 is, for example, an electrolytic solution impregnated in the positive electrode 201, the negative electrode 203, and the separator 402. In this way, in the battery 3000 having a configuration in which an electrolytic solution is used as the electrolyte, the electrolytic solution 401 impregnated in the separator 402 is located between the positive electrode 201 and the negative electrode 203. The electrolytic solution 401 may fill the internal space of the exterior casing 403.

[0113] In the battery 3000, at least one selected from the group consisting of the positive electrode 201 and the negative electrode 203 contains the solid electrolyte material according to the first embodiment.

[0114] Examples of the shape of the battery according to the second embodiment include a coin type, a cylindrical type, a square type, a sheet type, a button type, a flat type, and a laminate type.

[0115] [Other Embodiments] (Additional Notes) The above description of the embodiments discloses the following techniques.

[0116] (Technology 1) A solid electrolyte material containing Li, Sn, M1, and F, where M1 is at least one selected from the group consisting of Al, Y, Zr, Ti, and Mg.

[0117] With the above-described configuration, the solid electrolyte material according to Technology 1 has improved lithium ion conductivity.

[0118] (Technology 2) The solid electrolyte material according to Technology 1, wherein M1 includes at least one selected from the group consisting of Al and Y.

[0119] With the above configuration, the lithium ion conductivity of the solid electrolyte material can be increased.

[0120] (Technology 3) The solid electrolyte material according to Technology 1, wherein the solid electrolyte material contains Li, Sn, Al, M2, and F. Here, M2 is at least one selected from the group consisting of Y, Zr, Ti, and Mg.

[0121] With the above configuration, the lithium ion conductivity of the solid electrolyte material can be increased.

[0122] (Technology 4) The solid electrolyte material according to any one of Technologies 1 to 3, wherein the ratio of the amount of substance of Li to the total amount of substance of cations other than Li is 1.7 or more and 4.2 or less.

[0123] With the above configuration, the lithium ion conductivity of the solid electrolyte material can be increased.

[0124] (Technology 5) The solid electrolyte material is represented by the following composition formula (1-1): Li6-(4-a1)b1(Sn 1-a1 M1 a1 ) b1 F6 Formula (1-1) wherein a1 and b1 satisfy the relational expressions of 0<a1<1 and 0<b1≦1.5.

[0125] With the above configuration, the lithium ion conductivity of the solid electrolyte material can be increased.

[0126] (Technology 6) The solid electrolyte material according to Technology 5, wherein a1 satisfies the relational expression 0.01≦a1≦0.99.

[0127] With the above configuration, the lithium ion conductivity of the solid electrolyte material can be increased.

[0128] (Technology 7) The solid electrolyte material according to Technology 5 or 6, wherein a1 satisfies the relational expression 0.01≦a1≦0.7.

[0129] With the above configuration, the lithium ion conductivity of the solid electrolyte material can be increased.

[0130] (Technology 8) The solid electrolyte material according to any one of Techniques 5 to 7, wherein M1 is Al, and a1 satisfies the relational expression 0.01≦a1≦0.99.

[0131] With the above configuration, the lithium ion conductivity of the solid electrolyte material can be increased.

[0132] (Technology 9) The solid electrolyte material according to any one of Techniques 5 to 8, wherein M1 is Al, and a1 satisfies the relational expression 0.01≦a1≦0.7.

[0133] With the above configuration, the lithium ion conductivity of the solid electrolyte material can be increased.

[0134] (Technology 10) The solid electrolyte material according to any one of Techniques 5 to 9, wherein b1 satisfies a relational expression of 0.8≦b1≦1.2.

[0135] With the above configuration, the lithium ion conductivity of the solid electrolyte material can be increased.

[0136] (Technology 11) The solid electrolyte material is represented by the following composition formula (2-1): Li6-(4-a2-(4-c2)x2)b2(Sn 1-a2-x2 Al a2 M2 x2 ) b2 F6 Formula (2-1) where a2, x2 and b2 satisfy the relational expressions of 0<a2<1, 0<x2<1, 0<a2+x2<1, and 0<b2≦1.5, and c2 is the valence of M2.

[0137] With the above configuration, the lithium ion conductivity of the solid electrolyte material can be increased.

[0138] (Technology 12) The solid electrolyte material according to Technology 11, wherein a2 satisfies the relational expression 0.01≦a2≦0.99.

[0139] With the above configuration, the lithium ion conductivity of the solid electrolyte material can be increased.

[0140] (Technology 13) The solid electrolyte material according to Technology 11 or 12, wherein a2 satisfies the relational expression 0.01≦a2≦0.7.

[0141] With the above configuration, the lithium ion conductivity of the solid electrolyte material can be increased.

[0142] (Technology 14) The solid electrolyte material according to any one of techniques 11 to 13, wherein b2 satisfies a relational expression of 0.8≦b2≦1.2.

[0143] With the above configuration, the lithium ion conductivity of the solid electrolyte material can be increased.

[0144] (Technology 15) A battery comprising: a positive electrode; a negative electrode; and a separator layer provided between the positive electrode and the negative electrode, wherein at least one selected from the group consisting of the positive electrode, the negative electrode, and the separator layer contains the solid electrolyte material according to any one of Technologies 1 to 14.

[0145] With the above-described configuration, the battery according to Technique 15 has excellent charge / discharge characteristics.

[0146] (Technology 16) The battery according to Technology 15, wherein the separator layer is a solid electrolyte layer.

[0147] With the above-described configuration, the battery according to Technique 16 has excellent charge / discharge characteristics.

[0148] (Technology 17) The battery according to Technology 16, wherein the solid electrolyte layer includes a first solid electrolyte layer and a second solid electrolyte layer, the first solid electrolyte layer is disposed between the positive electrode and the second solid electrolyte layer, the second solid electrolyte layer is disposed between the first solid electrolyte layer and the negative electrode, and the first solid electrolyte layer includes the solid electrolyte material.

[0149] With the above-described configuration, the battery according to Technique 17 has excellent charge / discharge characteristics.

[0150] Hereinafter, the present disclosure will be described in more detail with reference to examples and comparative examples.

[0151] Example 1 (Preparation of Solid Electrolyte Material) In an argon atmosphere having a dew point of -60°C or less (hereinafter referred to as "dry argon atmosphere"), raw material powders of LiF, SnF4, and AlF3 were prepared in a molar ratio of LiF:SnF4:AlF3 = 2.7:0.3:0.7. These raw material powders were pulverized and mixed in a mortar. The obtained mixed powder was milled for 12 hours at 500 rpm using a planetary ball mill. In this way, a powder of a solid electrolyte material according to Example 1 was obtained. The solid electrolyte material according to Example 1 contained Li, 2.7 Sn 0.3 Al 0.7 It had a composition represented by F6.

[0152] (Evaluation of Ionic Conductivity) FIG. 4 shows a schematic diagram of a pressure forming die 500 used to evaluate the ionic conductivity of the solid electrolyte material.

[0153] The pressure molding die 500 had an upper punch 501, a frame 502, and a lower punch 503. The frame 502 was made of insulating polycarbonate. The upper punch 501 and the lower punch 503 were made of electronically conductive stainless steel.

[0154] Using the pressure molding die 500 shown in FIG. 4, the ionic conductivity of the solid electrolyte material of Example 1 was evaluated by the following method.

[0155] In a dry atmosphere having a dew point of −60° C. or less, the powder of the solid electrolyte material according to Example 1 was filled into the inside of the pressing die 500. Inside the pressing die 500, a pressure of 400 MPa was applied to the solid electrolyte material according to Example 1 using the upper punch 501 and the lower punch 503.

[0156] While the pressure was still applied, the upper punch 501 and the lower punch 503 were connected to a potentiostat (Princeton Applied Research, VersaSTAT4) equipped with a frequency response analyzer. The upper punch 501 was connected to a working electrode and a potential measurement terminal. The lower punch 503 was connected to a counter electrode and a reference electrode. The impedance of the solid electrolyte material was measured by electrochemical impedance measurement at room temperature.

[0157] FIG. 5 is a graph showing a Cole-Cole plot obtained by measuring the impedance of the solid electrolyte material according to Example 1.

[0158] In Fig. 5, the real value of the impedance at the measurement point where the absolute value of the phase of the complex impedance is smallest was considered to be the resistance value for ion conduction of the solid electrolyte material. SE Using the resistance value, the ionic conductivity was calculated based on the following formula (A): σ=(R SE × S / t) -1 ...(A) where σ represents ionic conductivity, and S represents the contact area of ​​the solid electrolyte material with the punch upper portion 501 (equal to the cross-sectional area of ​​the hollow portion of the frame mold 502 in FIG. 4). SE represents the resistance value of the solid electrolyte material in impedance measurement, and t represents the thickness of the solid electrolyte material (i.e., the thickness of the layer formed from the powder 101 of the solid electrolyte material in FIG. 4).

[0159] The ionic conductivity of the solid electrolyte material according to Example 1 measured at 25°C was 3.89 × 10 -6 The viscosity was S / cm.

[0160] (Fabrication of Battery) In a dry argon atmosphere, the solid electrolyte material according to Example 1 and LiCoO2, which is a positive electrode active material, were prepared in a volume ratio of 30:70. These materials were mixed in an agate mortar. In this way, a positive electrode mixture was obtained.

[0161] Next, LiCl and YCl were prepared in a molar ratio of LiCl:YCl = 3:1. These materials were ground and mixed in a mortar. The resulting mixture was milled for 12 hours at 500 rpm using a planetary ball mill. In this way, a halide solid electrolyte (hereinafter referred to as "LYC") having a composition represented by LiYCl was obtained.

[0162] In an insulating tube having an inner diameter of 9.5 mm, LYC (60 mg), the solid electrolyte material according to Example 1 (26 mg), and the above-described positive electrode mixture (9.1 mg) were stacked in this order. A pressure of 300 MPa was applied to the resulting stack, forming a second solid electrolyte layer (LYC), a first solid electrolyte layer (the solid electrolyte material according to Example 1), and a positive electrode. That is, the first solid electrolyte layer formed from the solid electrolyte material according to Example 1 was sandwiched between the second solid electrolyte layer and the positive electrode. The thicknesses of the second solid electrolyte layer and the first solid electrolyte layer were 450 μm and 150 μm, respectively.

[0163] Next, metal In (thickness: 200 μm) was laminated on the second solid electrolyte layer, and a pressure of 80 MPa was applied to the resulting laminate to form a negative electrode.

[0164] Next, current collectors made of stainless steel were attached to the positive and negative electrodes, and current collecting leads were attached to the current collectors.

[0165] Finally, the inside of the insulating cylinder was isolated from the outside atmosphere using an insulating ferrule, and the inside of the cylinder was sealed. In this way, the battery according to Example 1 was obtained.

[0166] (Charge / Discharge Test) Fig. 6 is a graph showing the initial discharge characteristics of the battery according to Example 1. The initial charge / discharge characteristics were measured by the following method.

[0167] The battery according to Example 1 was placed in a thermostatic chamber at 85°C.

[0168] 27 μA / cm 2 The battery according to Example 1 was charged at a current density of 0.02 C until a voltage of 3.6 V was reached. The current density corresponds to a 0.02 C rate.

[0169] Next, 27 μA / cm 2 The battery according to Example 1 was discharged at a current density of 0.1 V until a voltage of 1.9 V was reached.

[0170] As a result of the charge-discharge test, the battery according to Example 1 had an initial discharge capacity of 548 μAh.

[0171] <Examples 2 to 10> (Preparation of Solid Electrolyte Material) In Examples 2 to 10, raw material powders of LiF, SnF4, and AlF3 were weighed out so as to satisfy a molar ratio of LiF:SnF4:AlF3=6-(4-a1)b1:(1-a1)b1:a1b1.

[0172] The "value of a1," "value of b1," and "Li / (Sn+Al)" in each of Examples 2 to 10 are shown in Table 1 below.

[0173] In Examples 2 to 10, the solid electrolyte materials were prepared in the same manner as in Example 1 above.

[0174] (Evaluation of Ionic Conductivity) Conductivity measurement cells for each of Examples 2 to 10 were prepared in a glove box maintained in a dry, low-oxygen atmosphere with a dew point of −60° C. or less and an oxygen value of 5 ppm or less, in the same manner as in Example 1 above.

[0175] Other than this, the ionic conductivity was measured in the same manner as in Example 1 above.

[0176] The ionic conductivities in Examples 2 to 10 above are shown in Table 1 below.

[0177] (Fabrication of Battery) In a glove box maintained in a dry, low-oxygen atmosphere with a dew point of −60° C. or less and an oxygen value of 5 ppm or less, the solid electrolyte material of each of Examples 2 to 10 and LiCoO2 as a positive electrode active material were weighed out in a volume ratio of solid electrolyte material:positive electrode active material = 30:70. These were mixed in an agate mortar to prepare a positive electrode mixture for each of Examples 2 to 10.

[0178] Other than these, the batteries of Examples 2 to 10 were fabricated in the same manner as in Example 1 above.

[0179] (Charge / Discharge Test) A charge / discharge test was performed on each of the batteries of Examples 2 to 10 in the same manner as in Example 1. The initial discharge characteristics of Examples 2 to 10 were similar to those of Example 1, and good charge / discharge characteristics were obtained.

[0180] Comparative Example 1 Using LiBF4 as the solid electrolyte material, evaluation and analysis were carried out in the same manner as in Example 1 above.

[0181] The ionic conductivity measured at 25°C is 6.67 x 10 -9 The viscosity was S / cm.

[0182] The solid electrolyte material of Comparative Example 1 was used as the positive electrode mixture and the solid electrolyte material used for the solid electrolyte layer.

[0183] Other than this, the battery was fabricated and the charge / discharge test was carried out in the same manner as in Example 1 above.

[0184] The initial discharge capacity of the battery of Comparative Example 1 was 0.01 μAh or less, and no charge / discharge operation was observed.

[0185] Table 1 shows the configurations and evaluation results of Examples 1 to 10 and Comparative Example 1 described above.

[0186]

[0187] <Discussion> The solid electrolyte materials according to Examples 1 to 10 had a melting point of 8×10 at room temperature (25° C.). -9 The ionic conductivity was as high as 100 S / cm or more.

[0188] The batteries according to Examples 1 to 10 were all charged and discharged at 85° C. On the other hand, the battery according to Comparative Example 1 was neither charged nor discharged.

[0189] Note that Ti and Zr are tetravalent like Sn, Y is trivalent like Al, and Mg has an ionic radius close to that of Sn. Therefore, it is considered that, even if M1 is an element other than Al, i.e., Y, Zr, Ti, or Mg, improved lithium ion conductivity can be obtained, as in the solid electrolyte materials of Examples 1 to 10.

[0190] The solid electrolyte materials according to Examples 1 to 10 do not contain sulfur and therefore do not generate hydrogen sulfide.

[0191] As described above, the solid electrolyte material according to the present disclosure has higher lithium ion conductivity than LiBF4, a conventional fluoride solid electrolyte material, and is suitable for providing a battery that can be charged and discharged well.

[0192] The solid electrolyte material of the present disclosure is used, for example, in an all-solid-state lithium-ion secondary battery.

[0193] REFERENCE SIGNS LIST 100 Solid electrolyte particles 101 Powder of solid electrolyte material 201 Positive electrode 202 Electrolyte layer 203 Negative electrode 204 Positive electrode active material particles 205 Negative electrode active material particles 301 Electrolyte layer 302 First solid electrolyte layer 303 Second solid electrolyte layer 401 Electrolyte solution 402 Separator 403 Outer casing 404, 405 Current collector 500 Pressure molding die 501 Upper punch 502 Frame 503 Lower punch 1000, 2000, 3000 Battery

Claims

1. A solid electrolyte material containing Li, Sn, M1, and F. Here, M1 is at least one selected from the group consisting of Al, Y, Zr, Ti, and Mg.

2. The solid electrolyte material according to claim 1, wherein M1 contains at least one selected from the group consisting of Al and Y.

3. The solid electrolyte material according to claim 1, wherein the solid electrolyte material contains Li, Sn, Al, M2, and F. Here, M2 is at least one selected from the group consisting of Y, Zr, Ti, and Mg.

4. The solid electrolyte material according to claim 1, wherein the ratio of the amount of substance of Li to the total amount of substance of cations other than Li is 1.7 or more and 4.2 or less.

5. The solid electrolyte material is represented by the following composition formula (1-1): Li6-(4-a1)b1(Sn 1-a1 M1 a1 ). b1 F6... Formula (1-1) Here, a1 and b1 satisfy the relational expressions of 0 < a1 < 1 and 0 < b1 ≤ 1.

5. The solid electrolyte material according to claim 2.

6. The solid electrolyte material according to claim 5, wherein a1 satisfies the relational expression 0.01 ≦ a1 ≦ 0.

99.

7. The solid electrolyte material according to claim 5, wherein a1 satisfies the relational expression 0.01 ≦ a1 ≦ 0.

7.

8. The solid electrolyte material according to claim 5, wherein M1 is Al and a1 satisfies the relational expression 0.01 ≦ a1 ≦ 0.

99.

9. The solid electrolyte material according to claim 5, wherein M1 is Al and a1 satisfies the relational expression 0.01 ≦ a1 ≦ 0.

7.

10. The solid electrolyte material according to claim 5, wherein b1 satisfies the relational expression 0.8 ≦ b1 ≦ 1.

2.

11. The solid electrolyte material is represented by the following compositional formula (2-1): Li6-(4-a2-(4-c2)x2)b2(Sn 1-a2-x2 Al a2 M2 x2 ) b2 F6 ··· Formula (2-1) Here, a2, x2, and b2 satisfy the relational expressions of 0 < a2 < 1, 0 < x2 < 1, 0 < a2 + x2 < 1, and 0 < b2 ≤ 1.5, and c2 is the valence of M2. The solid electrolyte material according to claim 3.

12. The solid electrolyte material according to claim 11, wherein a2 satisfies the relational expression 0.01 ≦ a2 ≦ 0.

99.

13. The solid electrolyte material according to claim 11, wherein a2 satisfies the relational expression 0.01 ≦ a2 ≦ 0.

7.

14. The solid electrolyte material according to claim 11, wherein b2 satisfies the relational expression 0.8 ≦ b2 ≦ 1.

2.

15. A battery comprising a positive electrode, a negative electrode, and a separator layer provided between the positive electrode and the negative electrode, wherein at least one selected from the group consisting of the positive electrode, the negative electrode, and the separator layer contains the solid electrolyte material according to any one of claims 1 to 14.

16. The battery according to claim 15, wherein the separator layer is a solid electrolyte layer.

17. The solid electrolyte layer includes a first solid electrolyte layer and a second solid electrolyte layer. The first solid electrolyte layer is disposed between the positive electrode and the second solid electrolyte layer. The second solid electrolyte layer is disposed between the first solid electrolyte layer and the negative electrode. The first solid electrolyte layer contains the solid electrolyte material. The battery according to claim 16.