Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
  • H01M10/0561—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of inorganic materials only
  • H01M10/0562—Solid materials
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/052—Li-accumulators
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/052—Li-accumulators
  • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M2300/00—Electrolytes
  • H01M2300/0017—Non-aqueous electrolytes
  • H01M2300/0065—Solid electrolytes
  • H01M2300/0068—Solid electrolytes inorganic
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M2300/00—Electrolytes
  • H01M2300/0017—Non-aqueous electrolytes
  • H01M2300/0065—Solid electrolytes
  • H01M2300/0068—Solid electrolytes inorganic
  • H01M2300/008—Halides
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/10—Energy storage using batteries

Definitions

• This disclosure relates to a solid electrolyte material and a battery using the same.
• Patent Document 1 discloses LiBF4 as a fluoride solid electrolyte material.
• the objective of this disclosure is to provide a fluoride solid electrolyte material with improved lithium ion conductivity.
• the solid electrolyte material of the present disclosure includes Li, Sn, M1, and F.
• M1 is at least one selected from the group consisting of Al, Y, Zr, Ti, and Mg.
• the present disclosure provides a fluoride solid electrolyte material with improved lithium ion conductivity.
• FIG. 1 shows a cross-sectional view of a battery 1000 that is a first example of a battery according to the second embodiment.
• FIG. 2 shows a cross-sectional view of a second example of a battery 2000 according to the second embodiment.
• FIG. 3 shows a cross-sectional view of a battery 3000 that is a third example of the battery according to the second embodiment.
• FIG. 4 shows a schematic diagram of a pressing 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 impedance measurement 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.
• the solid electrolyte material according to the first embodiment includes Li, Sn, M1, and F, where M1 is at least one selected from the group consisting of Al, Y, Zr, Ti, and Mg.
• the solid electrolyte material according to the first embodiment has improved lithium ion conductivity.
• 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 redox potential. On the other hand, F has a high electronegativity, so that the bond with Li is relatively strong. As a result, the lithium ion conductivity of the fluoride solid electrolyte material generally tends to be low. For example, LiBF 4 disclosed in Patent Document 1 has a low ion conductivity of 6.67 ⁇ 10 ⁇ 9 S/cm.
• 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.
• a high lithium ion conductivity is, for example, 8 ⁇ 10 ⁇ 9 S/cm or more at around room temperature (for example, 25° C.).
• the solid electrolyte material according to the first embodiment can have, for example, an ion conductivity of 8 ⁇ 10 ⁇ 9 S/cm or more.
• the solid electrolyte material according to the first embodiment is substantially free of sulfur. 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 as an impurity in the solid electrolyte material is, for example, 1 mol % or less. It is more desirable that the solid electrolyte material according to the first embodiment is free of sulfur. A solid electrolyte material that does not contain sulfur is excellent in safety because it does not generate hydrogen sulfide even when exposed to the atmosphere.
• the solid electrolyte material according to the first embodiment may further contain anions other than F.
• anions other than F examples of such anions are Cl, Br, I, O, S, or Se.
• the solid electrolyte material according to the first embodiment may consist essentially of Li, Sn, M1, and F.
• the solid electrolyte material according to the first embodiment consists essentially of Li, Sn, M1, and F
• 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.
• 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.
• 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 in which the solid electrolyte material is manufactured or stored. In the solid electrolyte material according to the first embodiment, the amount of such unavoidably mixed in elements is, for example, 1 mol % or less.
• M1 may contain at least one selected from the group consisting of Al and Y.
• 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.
• the solid electrolyte material according to the first embodiment may be represented by the following composition formula (1-1).
• a1 and b1 satisfy the relational expressions of 0 ⁇ a1 ⁇ 1 and 0 ⁇ b1 ⁇ 1.5.
• M1 is at least one selected from the group consisting of Al and Y, which are trivalent cations.
• the solid electrolyte material according to the first embodiment is represented by composition formula (1-1), the solid electrolyte material according to the first embodiment can further improve ionic conductivity.
• the solid electrolyte material according to the first embodiment may contain a crystalline phase represented by composition formula (1-1).
• the solid electrolyte material according to the first embodiment may further contain oxygen (O).
• the solid electrolyte material according to the first embodiment may be represented by the following composition formula (1-2). Li 6-(4-a1)b1 (Sn 1-a1 M1 a1 ) b1 F 6-2d1 O d1 ...Formula (1-2)
• a1, b1, and M1 in the composition formula (1-2) are the same as a1, b1, and M1 in the composition formula (1-1), respectively.
• d1 satisfies the relational expression 0 ⁇ d1 ⁇ 3.
• composition formula (1-2) 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, just as when the solid electrolyte material is represented by composition formula (1-1).
• the solid electrolyte material according to the first embodiment may contain a crystalline phase represented by composition formula (1-2).
• composition formula (1-1) and composition formula (1-2) may satisfy the relational expression 0.01 ⁇ a1 ⁇ 0.99.
• composition formula (1-1) and composition formula (1-2) may satisfy the relational expression 0.01 ⁇ a1 ⁇ 0.7.
• composition formula (1-1) and composition formula (1-2) may satisfy the relational expression 0.8 ⁇ b1 ⁇ 1.2.
• M1 may be Al.
• M1 may be Al and a1 may satisfy the relational expression of 0.01 ⁇ a1 ⁇ 0.99.
• the solid electrolyte material according to the first embodiment can have a higher ionic conductivity.
• M1 in the composition formulas (1-1) and (1-2), M1 may be Al and a1 may satisfy the relational expression of 0.01 ⁇ a1 ⁇ 0.7.
• 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.
• the solid electrolyte material according to the first embodiment may be represented by the following composition formula (2-1).
• a2, x2, and b2 satisfy the relational expressions of 0 ⁇ a2 ⁇ 1, 0 ⁇ x2 ⁇ 1, 0 ⁇ a2+x2 ⁇ 1, and 0 ⁇ b2 ⁇ 1.5.
• c2 is the valence of M2.
• the solid electrolyte material according to the first embodiment may contain a crystalline phase represented by composition formula (2-1).
• the solid electrolyte material according to the first embodiment may contain oxygen (O) as described above.
• the solid electrolyte material according to the first embodiment may be represented by the following composition formula (2-2).
• a2, b2, c2, and M2 in the composition formula (2-2) are the same as a2, b2, c2, and M2 in the composition formula (2-1), respectively.
• d2 satisfies the relational expression 0 ⁇ d2 ⁇ 3.
• the solid electrolyte material according to the first embodiment may contain a crystalline phase represented by composition formula (2-2).
• An effective means of 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
• Mg has an ionic radius close to that of Sn. Therefore, in solid electrolyte materials containing Li, Sn, Al, and F, Y, Zr, Ti, and Mg are each relatively easy to dissolve, and it is expected that lithium ion conductivity will improve. Solid electrolyte materials containing such crystalline phases have high ionic conductivity.
• composition formulas (2-1) and (2-2) may satisfy the relational expression 0.01 ⁇ a2 ⁇ 0.99.
• composition formulas (2-1) and (2-2) may satisfy the relational expression 0.01 ⁇ a2 ⁇ 0.7.
• b2 in composition formulas (2-1) and (2-2) may satisfy the relational expression 0.8 ⁇ b2 ⁇ 1.2.
• the solid electrolyte material according to the first embodiment may be crystalline or amorphous.
• the shape of the solid electrolyte material according to the first embodiment is not limited. Examples of the shape are needle-like, spherical, or elliptical.
• the solid electrolyte material according to the first embodiment may be particles.
• the solid electrolyte material according to the first embodiment may be formed to have a pellet or plate shape.
• the solid electrolyte material may have a median diameter of 0.1 ⁇ m or more and 100 ⁇ m or less.
• the median diameter means 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 measuring device or an image analyzer.
• the solid electrolyte material according to the first embodiment may have a median diameter of 0.5 ⁇ m or more and 10 ⁇ m 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 is well dispersed with other materials such as active materials.
• the solid electrolyte material according to the first embodiment can be produced, for example, by the following method.
• raw material powders of multiple halides are mixed together to obtain the desired composition.
• the desired composition is Li2.7Sn0.3Al0.7F6
• LiF, SnF4 , and AlF3 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.
• 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.
• 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 at least one hour.
• the raw material powders are preferably fired in a closed container such as a quartz tube.
• the composition of the solid electrolyte material can be determined, for example, by ICP atomic emission spectroscopy, ion chromatography, inert gas fusion-infrared absorption, or EPMA (Electron Probe Micro Analyzer) methods.
• ICP atomic emission spectroscopy ion chromatography
• EPMA Electrode Micro Analyzer
• the composition of Li, Sn, and M1 can be determined by ICP atomic emission spectroscopy
• the composition of F can be determined by ion chromatography.
• 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.
• 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.
• the battery according to the second embodiment has excellent charge/discharge characteristics because it contains the solid electrolyte material according to the first embodiment.
• the battery according to the second embodiment may be an all-solid-state battery in which a solid electrolyte is used as the electrolyte, or a liquid battery in which an electrolytic solution is used as the electrolyte.
• the all-solid-state battery may be a primary battery or a secondary battery.
• FIG. 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 from an electrolyte material.
• the electrolyte layer is, for example, a solid electrolyte layer, that is, battery 1000 is, for example, an all-solid-state battery.
• the first example battery 1000 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.
• the positive electrode 201 contains a positive electrode active material 204 and a solid electrolyte 100.
• the electrolyte layer 202 contains an electrolyte material.
• 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.
• the positive electrode 201 contains a material capable of absorbing and releasing metal ions (e.g., lithium ions).
• the material is, for example, the positive electrode active material 204.
• (A, B, C) means "at least one selected from the group consisting of A, B, and C.”
• the positive electrode active material 204 may have a median diameter larger than that of the solid electrolyte 100. This allows the positive electrode active material 204 and the solid electrolyte 100 to be well dispersed 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.
• 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 assistant and the binder.
• coating materials included in the coating layer include a sulfide solid electrolyte, an oxide solid electrolyte, or a halide solid electrolyte.
• the coating material may contain the solid electrolyte material according to the first embodiment in order to suppress oxidative decomposition of the sulfide solid electrolyte.
• the coating material may contain an oxide solid electrolyte in order 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, the overvoltage rise of the battery 1000 can be suppressed.
• the positive electrode 201 may have a thickness of 10 ⁇ m or more and 500 ⁇ m or less.
• 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.
• the electrolyte layer 202 may contain 50% by mass or more of the solid electrolyte material according to the first embodiment.
• the electrolyte layer 202 may contain 70% by mass or more of the solid electrolyte material according to the first embodiment.
• the electrolyte layer 202 may contain 90% by mass or more of the solid electrolyte material according to the first embodiment.
• the electrolyte layer 202 may consist only of the solid electrolyte material according to the first embodiment.
• the solid electrolyte material according to the first embodiment will be referred to as the first solid electrolyte material.
• a solid electrolyte material different from the first solid electrolyte material will be referred to as the second solid electrolyte material.
• 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.
• the electrolyte layer 202 may consist only of the second solid electrolyte material.
• the electrolyte layer 202 may have a thickness of 1 ⁇ m or more and 1000 ⁇ m or less. If the electrolyte layer 202 has a thickness of 1 ⁇ m or more, the positive electrode 201 and the negative electrode 203 are less likely to short-circuit. If the electrolyte layer 202 has a thickness of 1000 ⁇ m or less, the battery 1000 can operate at high power.
• Examples of the second solid electrolyte material are Li2MgX4 , Li2FeX4 , Li(Al,Ga,In) X4 , Li3 (Al,Ga,In) X6 , or LiI, where X is at least one selected from the group consisting of F, Cl, Br, and I.
• the electrolyte layer 202 may have a thickness of 1 ⁇ m or more and 1000 ⁇ m or less.
• the negative electrode 203 contains a material capable of absorbing and releasing metal ions (e.g., lithium ions).
• the material is, for example, the negative electrode active material 205.
• Examples of the negative electrode active material 205 are metal materials, carbon materials, oxides, nitrides, tin compounds, or silicon compounds.
• the metal material may be a single metal or an alloy.
• Examples of the metal material are lithium metal or lithium alloys.
• 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), silicon compounds, or tin compounds.
• the negative electrode active material 205 may be selected in consideration of the reduction resistance of the solid electrolyte material contained in the negative electrode 203.
• the negative electrode 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 negative electrode active materials are titanium oxide, indium metal, or lithium alloy.
• examples of titanium oxide are Li4Ti5O12 , LiTi2O4 , or TiO2 .
• 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 ⁇ m or more and 100 ⁇ m or less.
• the negative electrode active material 205 and the solid electrolyte 100 can be well dispersed in the negative electrode 203. This improves the charge and discharge characteristics of the battery 1000.
• the negative electrode active material 205 has a median diameter of 100 ⁇ m or less, the lithium diffusion rate in the negative electrode active material 205 improves. This allows the battery 1000 to operate at a high output.
• the negative electrode active material 205 may have a median diameter larger than that of the solid electrolyte 100. This allows the negative electrode active material 205 and the solid electrolyte 100 to be well dispersed 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.
• the negative electrode 203 may have a thickness of 10 ⁇ m or more and 500 ⁇ m or less.
• 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.
• the second solid electrolyte material may be a sulfide solid electrolyte.
• Examples of sulfide solid electrolytes are Li2S - P2S5 , Li2S - SiS2 , Li2S - B2S3 , Li2S - GeS2 , Li3.25Ge0.25P0.75S4 , or Li10GeP2S12 .
• the negative electrode 203 may contain a sulfide solid electrolyte to suppress reductive decomposition of the solid electrolyte material.
• the negative electrode active material By covering the negative electrode active material with an electrochemically stable sulfide solid electrolyte, it is possible to suppress contact between the first solid electrolyte material and the negative electrode active material. As a result, the internal resistance of the battery 1000 can be reduced.
• the second solid electrolyte material may be an oxide solid electrolyte.
• oxide solid electrolytes include: (i) NASICON-type solid electrolytes such as LiTi2 ( PO4 ) 3 or elemental substitutions thereof; (ii) Perovskite-type solid electrolytes such as (LaLi) TiO3 ; (iii ) LISICON-type solid electrolytes such as Li14ZnGe4O16, Li4SiO4 , LiGeO4 or elemental substitutions thereof ; (iv) a garnet-type solid electrolyte such as Li7La3Zr2O12 or its elemental substitutions, or (v) Li3PO4 or its N - substituted derivatives ; It is.
• the second solid electrolyte material may be a halide solid electrolyte.
• halide solid electrolytes are Li2MgX4 , Li2FeX4 , Li(Al,Ga,In) X4 , Li3 (Al,Ga,In) X6 , or LiI, where X is at least one selected from the group consisting of F, Cl, Br, and I.
• halide solid electrolyte is a compound represented by Li a Me b Y c X 6.
• Me is at least one selected from the group consisting of metal elements other than Li and Y and metalloid elements.
• X is at least one selected from the group consisting of F, Cl, Br, and I.
• m represents the valence of Me.
• the "metalloid elements" are B, Si, Ge, As, Sb, and Te.
• the “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).
• 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.
• the halide solid electrolyte may be Li3YCl6 or Li3YBr6 .
• the second solid electrolyte material may be an organic polymer solid electrolyte.
• organic polymer solid electrolytes examples include polymer compounds and lithium salt compounds.
• 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 the ionic conductivity.
• lithium salt examples include LiPF6 , LiBF4 , LiSbF6, LiAsF6 , LiSO3CF3 , LiN ( SO2CF3 ) 2 , LiN(SO2C2F5)2, LiN(SO2CF3)(SO2C4F9 ) , or LiC ( SO2CF3 ) 3 .
• 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.
• 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 transfer of lithium ions and improve the output characteristics of the battery.
• the non-aqueous electrolyte contains a non-aqueous solvent and a lithium salt dissolved in the non-aqueous solvent.
• non-aqueous solvents examples include cyclic carbonate solvents, chain carbonate solvents, cyclic ether solvents, chain ether solvents, cyclic ester solvents, chain ester solvents, or fluorine solvents.
• cyclic carbonate solvents are ethylene carbonate, propylene carbonate, or butylene carbonate.
• chain carbonate solvents are dimethyl carbonate, ethyl methyl carbonate, or diethyl carbonate.
• Examples of cyclic ether solvents are tetrahydrofuran, 1,4-dioxane, or 1,3-dioxolane.
• chain ether solvents are 1,2-dimethoxyethane or 1,2-diethoxyethane.
• An example of a cyclic ester solvent is ⁇ -butyrolactone.
• An example of a chain ester solvent is methyl acetate.
• fluorine solvents are fluoroethylene carbonate, methyl fluoropropionate, fluorobenzene, fluoroethyl methyl carbonate, or fluorodimethylene carbonate.
• One type of non-aqueous solvent selected from these may be used alone. Alternatively, a combination of two or more types of non-aqueous solvents selected from these may be used.
• lithium salt examples include LiPF6 , LiBF4 , LiSbF6, LiAsF6 , LiSO3CF3 , LiN ( SO2CF3 ) 2 , LiN ( SO2C2F5 ) 2 , LiN( SO2CF3 )(SO2C4F9), or LiC( SO2CF3 ) 3 .
• One type of lithium salt selected from these may be used alone. Alternatively, a mixture of two or more types of 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.
• a polymer material impregnated with a non-aqueous electrolyte may be used.
• polymer materials are polyethylene oxide, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, or a polymer having an ethylene oxide bond.
• cations contained in ionic liquids 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, It is.
• Aliphatic chain quaternary salts such as tetraalkylammonium or tetraalkylphosphonium
• aliphatic cyclic ammoniums such as pyrrolidiniums, morpholiniums, imidazoliniums, tetrahydropyrimidiniums, piperaziniums, or piperidiniums
• nitrogen-containing heterocyclic aromatic cations
• Examples of anions contained in the ionic liquid are PF6- , BF4- , SbF6- - , AsF6- , SO3CF3- , N ( SO2CF3 ) 2- , N ( SO2C2F5 ) 2- , N ( SO2CF3 ) ( SO2C4F9 ) - , or C ( SO2CF3 ) 3- .
• the ionic liquid may contain a lithium salt.
• 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.
• binders are polyvinylidene fluoride, polytetrafluoroethylene, polyethylene, polypropylene, aramid resin, polyamide, polyimide, polyamideimide, polyacrylonitrile, polyacrylic acid, polyacrylic acid methyl ester, polyacrylic acid ethyl ester, polyacrylic acid hexyl ester, polymethacrylic acid, polymethacrylic acid methyl ester, polymethacrylic acid ethyl ester, polymethacrylic acid hexyl ester, polyvinyl acetate, polyvinylpyrrolidone, polyether, polyethersulfone, hexafluoropolypropylene, styrene butadiene rubber, or carboxymethylcellulose.
• Copolymers may also be used as binders.
• binders are 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.
• a mixture of two or more of these materials may be used as a binder.
• At least one selected from the positive electrode 201 and the negative electrode 203 may contain a conductive additive to improve electronic conductivity.
• Examples of the conductive additive include: (i) graphites, such as natural or synthetic graphite; (ii) Carbon blacks such as acetylene black or ketjen black; (iii) conductive fibers, such as carbon or metal fibers; (iv) fluorocarbons, (v) metal powders such as aluminum; (vi) conductive whiskers such as zinc oxide or potassium titanate; (vii) a conductive metal oxide, such as titanium oxide; or (viii) a conductive polymer, such as polyaniline, polypyrrole, or polythiophene.
• the conductive assistant i) or (ii) above may be used.
• 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 second example battery 2000 has a configuration in which an electrolyte layer 301 is provided instead of the electrolyte layer 202 in the first example battery 1000.
• 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.
• 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.
• the second solid electrolyte layer 303 may contain a sulfide solid electrolyte in order to suppress the 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.
• 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.
• the positive electrode 201, the negative electrode 203, the separator 402, and the electrolyte 401 are contained in the exterior 403.
• the electrolyte 401 is, for example, an electrolyte impregnated in the positive electrode 201, the negative electrode 203, and the separator 402.
• the electrolyte 401 impregnated in the separator 402 is located between the positive electrode 201 and the negative electrode 203.
• the electrolyte 401 may fill the internal space of the exterior 403.
• 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.
• Examples of the shape of the battery according to the second embodiment include a coin type, a cylindrical type, a rectangular type, a sheet type, a button type, a flat type, or a laminated type.
• the solid electrolyte material according to Technology 1 has improved lithium ion conductivity.
• the above configuration can improve the lithium ion conductivity of the solid electrolyte material.
• the solid electrolyte material includes Li, Sn, Al, M2, and F;
• M2 is at least one selected from the group consisting of Y, Zr, Ti, and Mg.
• the above configuration can improve the lithium ion conductivity of the solid electrolyte material.
• the solid electrolyte material is represented by the following composition formula (1-1): Li 6-(4-a1)b1 (Sn 1-a1 M1 a1 ) b1 F 6 ...Formula (1-1)
• a1 and b1 satisfy the relational expressions of 0 ⁇ a1 ⁇ 1 and 0 ⁇ b1 ⁇ 1.5.
• the above configuration can improve the lithium ion conductivity of the solid electrolyte material.
• the above configuration can improve the lithium ion conductivity of the solid electrolyte material.
• the above configuration can improve the lithium ion conductivity of the solid electrolyte material.
• the above configuration can improve the lithium ion conductivity of the solid electrolyte material.
• the above configuration can improve the lithium ion conductivity of the solid electrolyte material.
• the above configuration can improve the lithium ion conductivity of the solid electrolyte material.
• the solid electrolyte material is represented by the following composition formula (2-1): Li 6-(4-a2-(4-c2)x2)b2 (Sn 1-a2-x2 Al a2 M2 x2 ) b2 F 6 ...Formula (2-1)
• a2, x2, and b2 satisfy the relational expressions of 0 ⁇ a2 ⁇ 1, 0 ⁇ x2 ⁇ 1, 0 ⁇ a2+x2 ⁇ 1, and 0 ⁇ b2 ⁇ 1.5
• c2 is the valence of M2.
• the above configuration can improve the lithium ion conductivity of the solid electrolyte material.
• the above configuration can improve the lithium ion conductivity of the solid electrolyte material.
• the above configuration can improve the lithium ion conductivity of the solid electrolyte material.
• the above configuration can improve the lithium ion conductivity of the solid electrolyte material.
• the battery according to Technology 15 has excellent charge/discharge characteristics.
• the separator layer is a solid electrolyte layer. 16. The battery according to claim 15.
• the battery using Technology 16 has excellent charge/discharge characteristics.
• 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. 17. The battery according to claim 16.
• the battery according to Technology 17 has excellent charge/discharge characteristics.
• FIG. 4 shows a schematic diagram of a pressing die 500 used to evaluate the ionic conductivity of the solid electrolyte material.
• the pressure molding die 500 had an upper punch 501, a frame mold 502, and a lower punch 503.
• the frame mold 502 was made of insulating polycarbonate.
• the upper punch 501 and the lower punch 503 were made of electronically conductive stainless steel.
• the ionic conductivity of the solid electrolyte material of Example 1 was evaluated by the following method using the pressure molding die 500 shown in Figure 4.
• the powder of the solid electrolyte material according to Example 1 was filled into the inside of the pressure molding die 500. Inside the pressure molding 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.
• 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 terminal for measuring potential.
• 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.
• FIG. 5 is a graph showing the Cole-Cole plot obtained by impedance measurement of the solid electrolyte material of Example 1.
• the real value of the impedance at the measurement point where the absolute value of the phase of the complex impedance is the smallest was regarded as the resistance value for the ionic conduction of the solid electrolyte material.
• the resistance value For the real value, see the arrow R SE shown in Fig. 5.
• ⁇ represents ionic conductivity
• 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.
• R SE represents the resistance value of the solid electrolyte material in impedance measurement
• 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).
• the ionic conductivity of the solid electrolyte material according to Example 1 measured at 25° C. was 3.89 ⁇ 10 ⁇ 6 S/cm.
• LYC halide solid electrolyte having a composition represented by Li3YCl6
• LYC 60 mg
• the solid electrolyte material according to Example 1 26 mg
• the above-mentioned positive electrode mixture 9.1 mg
• 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 ⁇ m and 150 ⁇ m, respectively.
• metal In (thickness: 200 ⁇ m) was laminated on the second solid electrolyte layer. A pressure of 80 MPa was applied to the resulting laminate to form the negative electrode.
• current collectors made of stainless steel were attached to the positive and negative electrodes, and current collecting leads were attached to the current collectors.
• (Charge/discharge test) 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.
• the battery according to Example 1 was placed in a thermostatic chamber at 85°C.
• the battery according to Example 1 was charged at a current density of 27 ⁇ A/cm 2 until a voltage of 3.6 V was reached, which corresponds to a 0.02 C rate.
• Example 1 The cell according to Example 1 was then discharged at a current density of 27 ⁇ A/cm 2 until a voltage of 1.9 V was reached.
• the battery of Example 1 had an initial discharge capacity of 548 ⁇ Ah.
• Example 2 to 10 (Preparation of solid electrolyte material)
• Example 2 the solid electrolyte materials were prepared in the same manner as in Example 1 above.
• the ionic conductivity measured at 25° C. was 6.67 ⁇ 10 ⁇ 9 S/cm.
• the solid electrolyte material of Comparative Example 1 was used as the solid electrolyte material for the positive electrode mixture and the solid electrolyte layer.
• the initial discharge capacity of the battery in Comparative Example 1 was less than 0.01 ⁇ Ah, and no charging or discharging operation could be confirmed.
• the solid electrolyte materials according to Examples 1 to 10 had high ionic conductivity of 8 ⁇ 10 ⁇ 9 S/cm or more at room temperature (25° C.).
• 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.
• the solid electrolyte materials of Examples 1 to 10 do not contain sulfur, so hydrogen sulfide is not generated.
• the solid electrolyte material according to the present disclosure has a higher lithium ion conductivity than LiBF 4 , which is a conventional fluoride solid electrolyte material, and is suitable for providing a battery that can be charged and discharged well.
• the solid electrolyte material disclosed herein is used, for example, in all-solid-state lithium-ion secondary batteries.

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