Sulfides

Abstract

To provide a material having high ion conductivity without containing expensive elements such as In and Ga and useful as a solid electrolyte.SOLUTION: Sulfides represented by the formula: Na3-xZn1-xAl1+xS4 [where, x is 0 or over and 0.5 or under] is disclosed herein.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to sulfides, particularly sulfides useful as solid electrolytes. [Background technology]

[0002] Recent research has suggested that Na3ZnMS4 (M = In, Ga) crystals have a structure with high ionic conductivity (Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] S. Han, JY Seo, WB Park, AB Ikhe, SY Choi, SC Han, KS Sohn and M. Pyo, J. Mater. Chem. A, 10 (2022) 25039-25046. Summary of the Invention [Problem to be solved by the invention]

[0004] The materials using In and Ga in Non-Patent Document 1 are expensive and industrially disadvantageous. The present disclosure aims to provide a material that has high ionic conductivity and is useful as a solid electrolyte without containing expensive elements such as In and Ga. [Means for solving the problem]

[0005] The present disclosure includes the following aspects: [Section 1] formula: Na 3-x Zn 1-x Al 1+x S4 [In the formula, x is 0 or more and 0.5 or less.] Sulfides represented by: [Section 2] Item 1. The sulfide according to Item 1, wherein x is 0.25 or less. [Section 3] Item 3. The sulfide according to Item 1 or 2, wherein x is 0.01 or more. [Section 4] Item 4. The sulfide according to any one of Items 1 to 3, which is a solid electrolyte for a sodium ion battery. [Section 5] Item 5. The sulfide according to any one of items 1 to 4, which is a solid electrolyte for an all-solid-state sodium ion battery. [Section 6] Item 6. A battery member comprising the sulfide according to any one of Items 1 to 5. [Section 7] Item 7. The battery member according to Item 6, wherein the battery member is a negative electrode. [Section 8] Item 7. The battery member according to Item 6, wherein the battery member is a positive electrode. [Section 9] Item 7. The battery member according to Item 6, wherein the battery member is an electrolyte layer. [Section 10] Item 7. The battery member according to Item 6, wherein the battery member is a solid electrolyte layer. [Section 11] Item 7. A battery comprising the battery component according to item 6. [Section 12] formula: Na 3-x Zn 1-x Al 1+x S4 [In the formula, x is 0 or more and 0.5 or less.] A method for producing a sulfide represented by the formula: Na2S n (n is 1 or more and 10 or less), a raw material mixing step of mixing S, Zn, and Al to obtain a mixture; a heating step of heating the mixture to obtain a heat-treated product; and a cooling step of cooling the heat-treated product A manufacturing method comprising: [Section 13] Item 13. The method according to item 12, wherein the heating step is carried out at normal pressure. [Section 14] Item 14. The method according to item 12 or 13, wherein the heating step is carried out at 500°C or higher and 1000°C or lower. [Effects of the Invention]

[0006] The sulfide in the present disclosure has good sodium ion conductivity and is useful as a solid electrolyte for sodium ion batteries. In addition, the sulfide in the present disclosure is inexpensive and industrially advantageous because it is composed only of general-purpose elements. DETAILED DESCRIPTION OF THE INVENTION

[0007] <Sulfide> [Characteristics of sulfides] The sulfide in the present disclosure has good ionic conductivity and is useful as a solid electrolyte. Furthermore, since the sulfide in the present disclosure is composed only of general-purpose elements, it is inexpensive and industrially advantageous. Furthermore, the sulfide in the present disclosure may also have excellent moisture resistance (moisture stability).

[0008] [Composition of sulfides, etc.] The sulfide in this disclosure has the formula: Na 3-x Zn 1-x Al 1+x S4 [In the formula, x is 0 or more and 0.5 or less.] It may be expressed as:

[0009] x represents the degree of introduction of sodium defects in the sulfide and may be related to the degree of formation of a solid solution. x may be 0 or more, greater than 0, 0.01 or more, 0.03 or more, 0.05 or more, 0.07 or more, 0.10 or more, 0.15 or more, 0.20 or more, 0.25 or more, or 0.30 or more, for example, 0.01 or more, and may be 0.50 or less, 0.45 or less, 0.40 or less, 0.35 or less, 0.30 or less, 0.25 or less, 0.20 or less, 0.15 or less, 0.10 or less, or 0.05 or less, for example, 0.25 or less, and in one embodiment, 0 or more and 0.5 or less, 0 or more and 0.25 or less, or 0.03 or more and 0.025 or less. Setting x to greater than 0 (introducing sodium defects) is preferable from the viewpoint of particularly improving ionic conductivity.

[0010] The sulfide in the present disclosure may be crystalline, glass, or glass ceramic (crystallized glass). Glass ceramic refers to a mixture of crystalline and amorphous materials, particularly a material having a glass phase and a crystalline phase dispersed (precipitated) in the glass phase. The crystalline content of the sulfide may be 10% by weight or more, 30% by weight or more, 50% by weight or more, or 70% by weight or more, and may be 90% by weight or less, 70% by weight or less, 50% by weight or less, or 30% by weight or less, and in one embodiment, 10% by weight or more and 90% by weight or less. The proportion of the crystalline portion can be measured by observation with a transmission electron microscope or crystal structure analysis using the Rietveld method, and can be adjusted by changing the heating temperature or cooling conditions in the manufacturing process.

[0011] The sulfide in the present disclosure may have a tetragonal crystalline phase and a space group of I41 / acd. Specifically, the sulfide may have a structure in which a (Zn / Al)S4 tetrahedron has corners sharing, and in particular, Zn and Al occupy approximately half of each site.

[0012] [Method for producing sulfide] The method for producing the sulfide of the present disclosure is not particularly limited, but Raw material mixing process to mix raw materials to obtain a mixture a heating step of heating the mixture to obtain a heat-treated product; and Cooling process to cool the heat-treated material In each step, an inert gas atmosphere such as a nitrogen gas atmosphere or an argon gas atmosphere is preferably used to suppress side reactions of the materials. The raw material mixing step and the heating step may be performed simultaneously.

[0013] [Raw material mixing process] In the raw material mixing step, the raw materials are mixed. The mixing ratio of each raw material can be mixed so as to obtain the composition of the sulfide of the present disclosure described above.

[0014] An example of a raw material is Na2S. n(n is 1 or more and 10 or less, and may be 8 or less, 6 or less, 4 or less, or 2 or less, for example, 1), S, Zn, and an optional component, Al, in a predetermined ratio, but are not limited to these.

[0015] As a mixing method, various methods that can uniformly mix the raw materials can be used, such as mortar mixing, mechanical milling, coprecipitation, a method in which the raw materials are dispersed in a solvent and then mixed, a method in which the raw materials are dispersed in a solvent at once and then mixed, etc.

[0016] [Heating process] The heating temperature in the heating step may be 250 ° C. or higher, 300 ° C. or higher, 400 ° C. or higher, 450 ° C. or higher, 500 ° C. or higher, 550 ° C. or higher, 600 ° C. or higher, 650 ° C. or higher, 700 ° C. or higher, 750 ° C. or higher, 800 ° C. or higher, 850 ° C. or higher, or 900 ° C. or higher, for example, 500 ° C. or higher, particularly 600 ° C. or higher, and may be 2000 ° C. or lower, 1500 ° C. or lower, 1200 ° C. or lower, 1000 ° C. or lower, 800 ° C. or lower, 600 ° C. or lower, or 500 ° C. or lower, for example, 1000 ° C. or lower. A temperature of not lower than the above lower limit is preferable from the viewpoint of allowing the reaction to proceed sufficiently, and a temperature of not higher than the above upper limit is preferable from the viewpoint of suppressing loss of Na or S and side reactions between the container and the raw materials, etc.

[0017] The heating step may be carried out at atmospheric pressure without using a sealed tube process. Because it can be carried out at atmospheric pressure, the production method of the present disclosure is relatively easy to use for large-scale synthesis.

[0018] The heating rate may be 10°C / hour or more, 60°C / hour or more, 120°C / hour or more, 180°C / hour or more, 240°C / hour or more, or 300°C / hour or more, and may be 3000°C / hour or less, 2000°C / hour or less, 1500°C / hour or less, 1000°C / hour or less, or 500°C / hour or less, and in one aspect, 50°C / hour or more and 3000°C / hour or less, or 100°C / hour or more and 1000°C / hour or more. When simple element S is contained, the heating rate may be 1200°C / hour or less, particularly 600°C / hour or less, from the viewpoint of favorably forming low-volatile sodium polysulfide.

[0019] The heating method is not particularly limited as long as it can realize the above-mentioned temperature rise rate. For example, an electric furnace, a hot plate, a muffle furnace, a high-frequency induction heating device, a rotary kiln, a sand bath, a salt bath, etc. can be used for heating. It is preferable that the heating device has a function that can adjust the temperature and time. The raw material may be in a molten state in the heating step, and it is preferable to select a heating device and configuration that can heat-treat the melt.

[0020] The heating time in the heating step may be 0.1 hours or more, 0.5 hours or more, 1 hour or more, 2 hours or more, 2 hours or more, 4 hours or more, 6 hours or more, or 8 hours or more, for example, 0.5 hours or more, particularly 5 hours or more, and may be 30 hours or less, 25 hours or less, 20 hours or less, 15 hours or less, 12 hours or less, 10 hours or less, 5 hours or less, or 3 hours or less, for example, 15 hours or less, and in one embodiment, 0.1 hours or more and 20 hours or less, particularly 1 hour or more and 15 hours or less. In the present disclosure, heating time refers to the maintenance time at the maximum temperature. A heating time of at least the lower limit is preferred from the viewpoint of sufficiently progressing the reaction, and a heating time of not more than the upper limit is preferred from the viewpoint of suppressing loss of Na and S and side reactions between the container and raw materials, etc.

[0021] [Cooling process] In the cooling step, the heat-treated product obtained in the heating step is cooled to a stable state (usually room temperature), and the cooling treatment at this time may be rapid cooling or slow cooling.

[0022] The temperature decreasing rate may be 10°C / hour or more, 60°C / hour or more, 150°C / hour or more, 300°C / hour or more, 600°C / hour or more, 1000°C / hour or more, 1000°C / hour or more, 5000°C / hour or more, 10000°C / hour or more, 15000°C / hour or more, 100000°C / hour or more, 500000°C / hour or more, or 1000000°C / hour or more, and may be 30000°C / hour or more. The heating rate may be 100°C / hour or less, 1,000,000°C / hour or less, 500,000°C / hour or less, 100,000°C / hour or less, 50,000°C / hour or less, 10,000°C / hour or less, 1,000°C / hour or less, 500°C / hour or less, 250°C / hour or less, 100°C / hour or less, or 60°C / hour or less, and in one aspect it is 10°C / hour or more and 3,000,000°C / hour or less.

[0023] In the case of quenching, the quenching can be carried out by iron pressing (pressing with a cooling plate), pouring the melt into a cooling medium such as twin roller quenching or single roller method, spraying the melt, or the like, and from the viewpoint of vitrification, the temperature drop rate may be 100,000°C / hour or more, 500,000°C / hour or more, or 1,000,000°C / hour or more.

[0024] When cooling by slow cooling, examples of the cooling method include temperature control of the heat-treated product by an electric furnace program or cooling by natural heat dissipation including air cooling, and the temperature drop rate may be, for example, 50,000°C / hour or less, 10,000°C / hour or less, 5,000°C / hour or less, 3,000°C / hour or less, 1,000°C / hour or less, 500°C / hour or less, 300°C / hour or less, 300°C / hour or less, or 100°C / hour or less.

[0025] The cooling rate near the melting point and at the glass transition temperature is particularly important for crystallinity, so if you want to increase the glassiness, you can cool it quickly near the melting point and the glass transition temperature, and if you want to increase the crystallinity, you can cool it slowly near the melting point and the glass transition temperature.

[0026] <Battery materials / batteries> [Battery type, etc.] The sulfides in the present disclosure can be suitably used as solid electrolytes in each component (any one or more of the positive electrode, negative electrode, and solid electrolyte layer, for example, any one) of a battery, particularly a sodium-ion battery. The battery (sodium-ion battery) may be a battery using a liquid electrolyte or an all-solid-state battery, and preferably an all-solid-state battery.

[0027] There is no particular limitation on the shape of the battery, and it may be cylindrical, rectangular, or the like.

[0028] [Positive Electrode] The positive electrode contains a positive electrode active material. The positive electrode may contain other components such as an electrolyte, a conductive auxiliary material, and a binder that may contain the sulfide of the present disclosure as required.

[0029] Examples of the positive electrode active material include materials that can occlude or release sodium ions during charge and discharge, such as sodium cobaltate (NaCoO2), sodium nickelate (NaNiO2), sodium manganate (NaMn2O4), sodium iron phosphate (NaFePO4), vanadium oxide-based materials, sulfur-based materials, etc. Specific examples include NaCoO2, NaCoN, NaMnO2, NaMn2O4, Na 0.44 MnO2, NaNi 0.5 Mn 0.5 O2, NaCo 1 / 3 Ni 1 / 3 Mn 1 / 3 O2, NaNiO2, NaVO2, NaFeO2, NaCrO2, NaVPO4F, Na2FePO4F, Na3V2(PO4)3, Na2FeS2-Na3PS4, V2O5, MoO3, TiS2, FeS, InSb, CuSb, MnSb, NaSn, NaSi, NaAl, NaGe, NaSb, Na(Ni x Mn 1-x )O2(0 < x < 1), Na(Fe x Mn 1-x )O2(0 < x < 1), Na 1+x Mn 2-x-y M y O4 (M is one or more metal elements selected from Al, Mg, Co, Fe, Ni, and Zn, 0 < x + y < 2), etc.

[0030] The amount of positive electrode active material in the positive electrode may be 10% by weight or more, 20% by weight or more, 30% by weight or more, 40% by weight or more, 60% by weight or more, 80% by weight or more, 90% by weight or more, or 95% by weight or more, for example, 50% by weight or more, preferably 75% by weight or more, more preferably 85% by weight or more, and particularly 90% by weight or more, and may be 100% by weight or less, 95% by weight or less, 90% by weight or less, 80% by weight or less, 70% by weight or less, 60% by weight or less, 50% by weight or less, 40% by weight or less, 30% by weight or less, or 20% by weight or less.

[0031] Examples of the electrolyte include the sulfide in the present disclosure and known electrolytes (for example, the electrolyte in the electrolyte layer described below).

[0032] The amount of sulfide of the present disclosure in the positive electrode can be 0.5% by weight or more, 1% by weight or more, 3% by weight or more, 5% by weight or more, 10% by weight or more, 20% by weight or more, 30% by weight or more, or 40% by weight or more, and can be 80% by weight or less, 70% by weight or less, 60% by weight or less, 50% by weight or less, 40% by weight or less, 30% by weight or less, 20% by weight or less, 10% by weight or less, 5% by weight or less, or 3% by weight or less.

[0033] The amount of solid electrolyte other than the sulfide of the present disclosure in the positive electrode may be 0.5 wt.% or more, 1 wt.% or more, 3 wt.% or more, 5 wt.% or more, 10 wt.% or more, 20 wt.% or more, 30 wt.% or more, or 40 wt.% or more, and may be 80 wt.% or less, 70 wt.% or less, 60 wt.% or less, 50 wt.% or less, 40 wt.% or less, 30 wt.% or less, 20 wt.% or less, 10 wt.% or less, 5 wt.% or less, or 3 wt.% or less.

[0034] Examples of the conductive additive include carbon materials such as graphite, coke, carbon black, acicular carbon, carbon fiber, and carbon nanotubes.

[0035] The amount of the conductive additive in the positive electrode may be 0.1% by weight or more, 0.3% by weight or more, 0.4% by weight or more, 0.5% by weight or more, 1% by weight or more, 3% by weight or more, 5% by weight or more, 10% by weight or more, or 20% by weight or more, and may be 30% by weight or less, 20% by weight or less, 10% by weight or less, 5% by weight or less, 3% by weight or less, 2% by weight or less, 1% by weight or less, or 0.5% by weight or less, and in one aspect, is preferably 0.2% by weight or more and 10% by weight or less, and particularly 0.4% by weight or more and 2% by weight or less.

[0036] Examples of binders include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), polyimide (PI), polyamide, polyamideimide, polyacrylic, styrene-butadiene rubber (SBR), styrene-ethylene-butylene-styrene copolymer (SEBS), carboxymethyl cellulose (CMC), and the like.

[0037] The amount of binder in the positive electrode may be 0.1 wt % or more, 0.3 wt % or more, 0.4 wt % or more, 0.5 wt % or more, 1 wt % or more, 3 wt % or more, 5 wt % or more, 10 wt % or more, or 20 wt % or more, and may be 30 wt % or less, 20 wt % or less, 10 wt % or less, 5 wt % or less, 3 wt % or less, 2 wt % or less, 1 wt % or less, or 0.5 wt % or less, and in one embodiment, is preferably 0.2 wt % or more and 10 wt % or less, and particularly 0.4 wt % or more and 2 wt % or less.

[0038] The positive electrode containing the above-mentioned components is connected to a positive electrode current collector made of Al, Ni, stainless steel, carbon cloth, etc. The positive electrode may be formed by coating a slurry prepared by mixing the above-mentioned components with an inert solvent on the surface of the current collector and drying the slurry.

[0039] [Negative electrode] The negative electrode includes a negative electrode active material. The negative electrode may include other components, such as an electrolyte that may include the sulfide of the present disclosure, a conductive additive, and a binder, as needed.

[0040] Examples of negative electrode active materials are materials that can absorb or release sodium ions during charge and discharge, and include metallic sodium, carbon-based materials (activated carbon, graphite, etc.), silicon, silicon oxide, Si-SiO-based materials, and sodium titanium oxide. Specific examples include Na, Na alloys, carbon-based negative electrode active materials (hard carbon, natural graphite, artificial graphite, etc.), Sn-based negative electrode active materials (NaSn2, Na2Sn, Na2Sn5, Na 15 Sn 4、 SnO 2、 NaSnO, CaSnO3, BaSnO 3、 Sn4P3, SnP), sodium titanate (Na2Ti3O7, Na4Ti5O 12 etc.), lithium titanates (e.g. Li2Ti3O7, Li4Ti5O 12 etc.), Si, Si alloys, Si-based negative electrode active materials, cobalt oxide, iron sulfide, Sb, Na—Sb alloys, P, P alloys, etc.

[0041] The amount of the negative electrode active material in the negative electrode may be 10% by weight or more, 20% by weight or more, 30% by weight or more, 40% by weight or more, 60% by weight or more, 80% by weight or more, 90% by weight or more, or 95% by weight or more, for example, 50% by weight or more, preferably 75% by weight or more, more preferably 85% by weight or more, and particularly 90% by weight or more, and may be 100% by weight or less, 95% by weight or less, 90% by weight or less, 80% by weight or less, 70% by weight or less, 60% by weight or less, 50% by weight or less, 40% by weight or less, 30% by weight or less, or 20% by weight or less.

[0042] Examples of the electrolyte include the sulfide in the present disclosure and known electrolytes (for example, the electrolyte in the electrolyte layer described below).

[0043] The amount of sulfides of the present disclosure in the negative electrode can be 0.5% by weight or more, 1% by weight or more, 3% by weight or more, 5% by weight or more, 10% by weight or more, 20% by weight or more, 30% by weight or more, or 40% by weight or more, and can be 80% by weight or less, 70% by weight or less, 60% by weight or less, 50% by weight or less, 40% by weight or less, 30% by weight or less, 20% by weight or less, 10% by weight or less, 5% by weight or less, or 3% by weight or less.

[0044] The amount of solid electrolyte other than the sulfide of the present disclosure in the negative electrode may be 0.5 wt.% or more, 1 wt.% or more, 3 wt.% or more, 5 wt.% or more, 10 wt.% or more, 20 wt.% or more, 30 wt.% or more, or 40 wt.% or more, and may be 80 wt.% or less, 70 wt.% or less, 60 wt.% or less, 50 wt.% or less, 40 wt.% or less, 30 wt.% or less, 20 wt.% or less, 10 wt.% or less, 5 wt.% or less, or 3 wt.% or less.

[0045] Examples of the conductive additive include carbon materials such as graphite, coke, carbon black, acicular carbon, carbon fiber, and carbon nanotubes.

[0046] The amount of the conductive additive in the negative electrode may be 0.1% by weight or more, 0.3% by weight or more, 0.4% by weight or more, 0.5% by weight or more, 1% by weight or more, 3% by weight or more, 5% by weight or more, 10% by weight or more, or 20% by weight or more, and may be 30% by weight or less, 20% by weight or less, 10% by weight or less, 5% by weight or less, 3% by weight or less, 2% by weight or less, 1% by weight or less, or 0.5% by weight or less, and in one aspect, is preferably 0.2% by weight or more and 10% by weight or less, and particularly 0.4% by weight or more and 2% by weight or less.

[0047] Examples of binders include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), polyimide (PI), polyamide, polyamideimide, polyacrylic, styrene-butadiene rubber (SBR), styrene-ethylene-butylene-styrene copolymer (SEBS), carboxymethyl cellulose (CMC), and the like.

[0048] The amount of binder in the negative electrode may be 0.1 wt % or more, 0.3 wt % or more, 0.4 wt % or more, 0.5 wt % or more, 1 wt % or more, 3 wt % or more, 5 wt % or more, 10 wt % or more, or 20 wt % or more, and may be 30 wt % or less, 20 wt % or less, 10 wt % or less, 5 wt % or less, 3 wt % or less, 2 wt % or less, 1 wt % or less, or 0.5 wt % or less, and in one embodiment, is preferably 0.2 wt % or more and 10 wt % or less, and particularly 0.4 wt % or more and 2 wt % or less.

[0049] The negative electrode containing the above-mentioned components is connected to a negative electrode current collector made of Al, Ni, Cu, stainless steel, carbon cloth, etc. The above-mentioned components may be mixed with an inert solvent to form a slurry, which may be applied to the surface of the current collector and then dried to form the negative electrode.

[0050] [Electrolyte layer] The electrolyte layer includes an electrolyte that may include the sulfide of the present disclosure. The electrolyte layer may include other components, such as a binder, as needed. The electrolyte layer is disposed in the battery so as to connect the positive electrode and the negative electrode.

[0051] The electrolyte layer can be roughly divided into a liquid electrolyte layer that mainly uses a liquid electrolyte and a solid electrolyte layer that uses a solid electrolyte.

[0052] (liquid electrolyte layer) The liquid electrolyte layer is preferably composed of a mixture of an electrolyte and a non-aqueous solvent that dissolves and disperses the electrolyte.

[0053] Examples of electrolytes in the liquid electrolyte layer include NaClO4, NaPF6, NaBF4, NaTiF4, NaVF5, NaAsF, NaAsF6, NaSbF6, NaCF3SO3, NaB(C2O4)2, NaB(C6H5)4, NaB 10 Cl 10 , NaB 12 Cl 12, Na2SO4, Na2S2O4, NaNO3, NaCl, NaBr, CH3SO3Na, CF3SO3Na, NaN(SO2CF3)2, NaN(SO2C2F5)2, NaC(SO2CF3)3 or NaN(SO3CF3)2, etc.

[0054] Examples of non-aqueous solvents include carbonates, ethers, ketones, sulfolane compounds, lactones, nitriles, chlorinated hydrocarbons, amines, esters, amides, and phosphate ester compounds. Representative examples of these include 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, ethylene carbonate, vinylene carbonate, methyl formate, dimethyl sulfoxide, propylene carbonate, acetonitrile, γ-butyrolactone, dimethylformamide, dimethyl carbonate, diethyl carbonate, sulfolane, ethyl methyl carbonate, 1,4-dioxane, 4-methyl-2-pentanone, 1,3-dioxolane, 4-methyl-1,3-dioxolane, diethyl ether, sulfolane, methyl sulfolane, propionitrile, benzonitrile, butyronitrile, valeronitrile, 1,2-dichloroethane, trimethyl phosphate, and triethyl phosphate.

[0055] The amount of sulfide of the present disclosure in the liquid electrolyte layer may be 40% by weight or more, 50% by weight or more, 60% by weight or more, 70% by weight or more, 80% by weight or more, 90% by weight or more, 95% by weight or more, or 97.5% by weight or more, preferably 80% by weight or more, more preferably 95% by weight or more, and may be 100% by weight or less, 95% by weight or less, 90% by weight or less, 85% by weight or less, 80% by weight or less, 70% by weight or less, 60% by weight or less, 50% by weight or less, 40% by weight or less, 30% by weight or less, 20% by weight or less, 10% by weight or less, 5% by weight or less, or 3% by weight or less, and in one embodiment, 80% by weight or more and 100% by weight or less, particularly 95% by weight or more and 100% by weight or less.

[0056] The amount of electrolyte other than the sulfide of the present disclosure in the liquid electrolyte layer may be 0.5 wt.% or more, 1 wt.% or more, 3 wt.% or more, 5 wt.% or more, 10 wt.% or more, 20 wt.% or more, 30 wt.% or more, or 40 wt.% or more, and may be 80 wt.% or less, 70 wt.% or less, 60 wt.% or less, 50 wt.% or less, 40 wt.% or less, 30 wt.% or less, 20 wt.% or less, 10 wt.% or less, 5 wt.% or less, or 3 wt.% or less.

[0057] The amount of the non-aqueous solvent in the liquid electrolyte layer may be 0.5 wt % or more, 1 wt % or more, 3 wt % or more, 5 wt % or more, 10 wt % or more, 20 wt % or more, 30 wt % or more, or 40 wt % or more, and may be 80 wt % or less, 70 wt % or less, 60 wt % or less, 50 wt % or less, 40 wt % or less, 30 wt % or less, 20 wt % or less, 10 wt % or less, 5 wt % or less, or 3 wt % or less.

[0058] The liquid electrolyte layer may include a separator to prevent short-circuiting between the positive electrode and the negative electrode. Examples of the separator include polyolefin resins such as polyethylene and polypropylene, fluororesins such as polyvinylidene fluoride, nylon, cellulose acetate, nitrocellulose, polysulfone, polyacrylonitrile, aromatic aramid, and inorganic glass, and may be in the form of a porous membrane, nonwoven fabric, woven fabric, or the like.

[0059] (Solid electrolyte layer) Examples of the solid electrolyte constituting the solid electrolyte layer include sulfides of the present disclosure and known sodium ion conductive materials, and examples thereof include sulfide solid electrolytes, oxide solid electrolytes, etc. Specifically, for example, Na2S-P2S5, Na2S-P2S5-NaI, Na2S-P2S5-NaI-NaBr, Na2S-P2S5-Na2O, Na2S-P2S5-Na2O-NaI, Na2S-SiS2, Na2S-SiS2-SiO2, Na2S-SiS2-NaI, Na2S-SiS2-NaBr, Na2S-SiS2-NaCl, Na2S-SiS2-B2S3-NaI, Na2S-SiS2-P2S5-NaI, Na2S-B2S3, Na2S-B2S3-SiO2, Na2S-GeS2-Ga2S3, Na2S-P2S5-GeS2, Na2S-GeS2, NaI-Na2S-P2O5, NaI-Na3PO4-P2S5, Na2S-P2S5, Na 10 GeP2S 12 、Na 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 、Na7P3S 11 、Na3PS4、Na 3.25 P 0.75 S4、Na6PS5I、Na 2.88 Sb 0.88 W 0.12 S 4、 Na 6-y PS 5-x Z 1+y (Z = Cl or Br, 0 < x < 5, 0 < y < 6), etc. of sulfide solid electrolytes, Na2O-B2O3-P2O3, Na2O-SiO2, Na2O-P2O5, Na5La3Ta2O 12 、Na7La3Zr2O 12 、Na3Zr2Si2PO 12 、Na6BaLa2Ta2O 12 、Na 3.6 Si 0.6 P 0.4 O4 or oxide solid electrolytes such as Na3BO3-Na2SO4-Na2CO3 are exemplified.

[0060] The amount of sulfide of the present disclosure in the solid electrolyte layer may be 40% by weight or more, 50% by weight or more, 60% by weight or more, 70% by weight or more, 80% by weight or more, 90% by weight or more, 95% by weight or more, or 97.5% by weight or more, preferably 80% by weight or more, more preferably 95% by weight or more, and may be 100% by weight or less, 95% by weight or less, 90% by weight or less, 85% by weight or less, 80% by weight or less, 70% by weight or less, 60% by weight or less, 50% by weight or less, 40% by weight or less, 30% by weight or less, 20% by weight or less, 10% by weight or less, 5% by weight or less, or 3% by weight or less, and in one embodiment, 80% by weight or more and 100% by weight or less, particularly 95% by weight or more and 100% by weight or less.

[0061] The amount of solid electrolyte other than the sulfide of the present disclosure in the solid electrolyte layer may be 0.5 wt % or more, 1 wt % or more, 3 wt % or more, 5 wt % or more, 10 wt % or more, 20 wt % or more, 30 wt % or more, or 40 wt % or more, and may be 80 wt % or less, 70 wt % or less, 60 wt % or less, 50 wt % or less, 40 wt % or less, 30 wt % or less, 20 wt % or less, 10 wt % or less, 5 wt % or less, or 3 wt % or less.

[0062] The electrolyte layer may contain other components such as a binder in addition to the electrolyte material. Examples of binders include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), polyimide (PI), polyamide, polyamideimide, polyacrylic, styrene-butadiene rubber (SBR), styrene-ethylene-butylene-styrene copolymer (SEBS), and carboxymethyl cellulose (CMC).

[0063] The amount of binder in the solid electrolyte layer may be 0.1 wt % or more, 0.3 wt % or more, 0.4 wt % or more, 0.5 wt % or more, 1 wt % or more, 3 wt % or more, 5 wt % or more, 10 wt % or more, or 20 wt % or more, and may be 30 wt % or less, 20 wt % or less, 10 wt % or less, 5 wt % or less, 3 wt % or less, 2 wt % or less, 1 wt % or less, or 0.5 wt % or less, and in one embodiment, is preferably 0.2 wt % or more and 10 wt % or less, particularly 0.4 wt % or more and 2 wt % or less.

[0064] The solid electrolyte layer can be obtained by pressing the solid electrolyte to a predetermined thickness. The pressure of the press may be 50 to 2000 MPa.

[0065] [Battery manufacturing method] (liquid electrolyte battery) When manufacturing a battery using a liquid electrolyte, for example, a laminate of a positive electrode, a separator, and a negative electrode is inserted into a battery can, and a mixture of the electrolyte and a non-aqueous solvent is poured into the battery can to obtain a sodium ion battery or secondary battery. The positive electrode, separator, and negative electrode may be stacked or wound.

[0066] (All-solid-state battery) When manufacturing an all-solid-state battery, a positive electrode, a solid electrolyte layer, a negative electrode, and a current collector are stacked and pressed to obtain a cell. The thickness of each layer may be, independently, for example, 0.1 μm or more, 1 μm or more, 10 μm or more, 100 μm or more, or 1000 μm or more, and may be 50,000 μm or less, 30,000 μm or less, 10,000 μm or less, 5,000 μm or less, 1000 μm or less, 500 μm or less, 300 μm or less, or 100 μm or less. In one embodiment, the thickness is 1 μm or more and 1000 μm or less, particularly 1 μm or more and 100 μm or less. The obtained cell is fixed to a housing as necessary.

[0067] Although the embodiments have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the claims. [Example]

[0068] The present disclosure will be described in detail below with reference to examples, but the present disclosure is not limited to these examples.

[0069] <Experimental Method> Since we mainly deal with materials that are unstable in the atmosphere, experiments are carried out in a glove box under a dry argon atmosphere unless otherwise noted below.

[0070] [X-ray diffraction measurement] X-ray diffraction measurements were performed to identify the crystalline phase of the prepared samples. A fully automatic multipurpose horizontal X-ray diffractometer (Smart Lab) manufactured by Rigaku Denki Co., Ltd. was used for the measurements. Powdered samples were measured using an airtight sample stage. CuKα radiation (λ = 1.54056 × 10 -10 The tube voltage was 40 kV, the tube current was 200 mA, and the scanning angle was 2θ = 5 to 80 deg. for normal measurements and 2θ = 5 to 120 deg. for measurements for Rietveld analysis. The sampling interval was 0.02 deg., and the scanning speed was 10 deg. min for normal measurements. -1 , 2 deg. min for measurements for Rietveld analysis -1 or 3 deg. min -1 It was decided.

[0071] [Rietveld analysis] To understand the detailed local structure, we performed Rietveld analysis. Rietveld analysis is an analytical technique that uses measured diffraction intensity data and a crystal structure model as inputs, adjusting structural parameters to refine the calculated and measured diffraction intensities as closely as possible (Izumi Nakai and Fujio Izumi, eds., Practical Powder X-ray Analysis, 3rd Edition, Asakura Shoten, (2021) pp. 130-132). The crystal structure parameters refined are the lattice constant, atomic fractional coordinates, atomic site occupancy, and atomic displacement parameters. In addition, parameters derived from the measurement method, sample state, and instrument (e.g., background, zero-point shift, sample displacement parameters, sample transmission parameters, surface roughness parameters, and profile symmetry parameters) are also refined. The actual Rietveld analysis was performed on experimental XRD patterns. The pattern fitting program used for Rietveld analysis was RIETAN-FP (F. Izumi and K. Momma, Solid State Phenom., 130 (2007) 15-20.).

[0072] [Raman spectroscopy] Raman spectroscopy was performed to investigate the local structure of the sample. A laser Raman spectroscopy system, LabRAM HR-800, manufactured by Horiba Ltd., was used for the measurements. The powder sample was packed into an aluminum pan in argon gas, fixed, and measured using an airtight sample stage. The powder sample was packed into an aluminum pan in argon gas, fixed, and measured using an airtight sample stage. A YAG laser (λ=532 nm) was used as the oscillation line.

[0073] [Ionic Conductivity] The ionic conductivity of the sample was measured by AC impedance measurement using a blocking electrode, as follows. The powder sample was uniaxially pressed at 360 MPa for 5 minutes using a hydraulic press in a glove box under a dry argon atmosphere to form a 10 mm pellet. The pellets were approximately 0.7–1.2 mm thick. Gold was sputtered onto both surfaces of the resulting pellet as a current collector using a quick coater (SANYU ELECTRON SC-701). The surface used as the current collector was 10 mm thick. The sample was then vacuum-sealed in a laminate cell. Specifically, an Al lead tab, a Ni lead tab, and a laminate sheet were stacked, and the three peripheral edges were heat-sealed using a sealer (NL-202JC-10, Ishizaki Electric). The pellet sample was then sandwiched between the Al and Ni lead tabs in the glove box and sealed under vacuum. Finally, clips were used to connect the Al and Ni lead tabs to the platinum lead wire inside the cylinder. The resistance of the sample was measured using a Solartron impedance analyzer (SI-1260). The measurement frequency range was 0.1 Hz to 107 Hz, and the AC amplitude was 10 mV. Measurement temperatures ranged from 25°C to 70°C. The resistance R (Ω) of the sample was read from the obtained complex impedance plot, and the ionic conductivity σ (S cm-1) was calculated using the following equation. σ = (1 / R) (L / S) L: pellet thickness (cm), S: electrode area

[0074] <Comparative example: Na3ZnMS4 (M = In, Ga), Na 2.8 Zn 0.8 Ga 1.2 Preparation and evaluation of S4

[0075] [Synthesis] Na3ZnInS4, Na3ZnGaS4, Na 2.8 Zn 0.8 Ga 1.2The procedure for preparing S4 is as follows: Under dry argon, the starting materials Na2S (NAGAO, 99.1%), S (Kojundo Chemical, 99.99%), Zn (Fujifilm Wako, 99.9%), and Ga2S3 (Aldrich, 99.99%) or In2S3 (Kojundo Chemical, 99.9%) were weighed out to a total of 0.75 g, mixed in a mortar, placed in a carbon crucible with an inner diameter of 20 mm, and heat-treated at 750 °C for 12 hours under a dry Ar atmosphere. After cooling to room temperature in a furnace over 6 hours, Na3ZnInS4, Na3ZnGaS4, and Na 2.8 Zn 0.8 Ga 1.2 S4 was obtained. The heating and cooling conditions and the raw material composition were as follows: [Heating and cooling conditions] 1. RT → 750℃ (3 h) 2. 750℃ (12h) 3. 750 °C → RT (6 h) [Raw material composition] Na3ZnMS4(M : In, Ga)=Na2S : S : Zn : Ga2S3or In2S3= 1.5 : 1 : 1 : 0.5 (molar ratio) Na 2.8 Zn 0.8 Ga 1.2 S4 = Na2S:S:Zn:Ga2S3 = 1.4:0.8:0.8:0.6 (molar ratio)

[0076] [Evaluation of structure and properties] Figure C1 shows the prepared Na3ZnMS4 (M = In, Ga), Na 2.8 Zn 0.8 Ga 1.2 The XRD patterns of Na3ZnGaS4 and Na 2.8 Zn 0.8 Ga 1.2 The XRD pattern of S4 is shown, enlarged from 33.5° to 35°. The XRD pattern of Na3ZnMS4 (M = In, Ga) is the same as that reported previously. [3]This indicates that Na3ZnMS4 (M = In, Ga) can be produced by heat treatment at atmospheric pressure. 2.8 Zn 0.8 Ga 1.2 In the XRD pattern of S4, the peak attributable to the 431 plane shifted to the higher angle side compared to the XRD pattern of Na3ZnGaS4, suggesting that the lattice volume had decreased. This suggests that Zn has been substituted with Ga, which has a smaller ionic radius, and that Na 2.8 Zn 0.8 Ga 1.2 Figure C2 shows the results of the synthesis of Na3ZnMS4 (M = In, Ga), Na 2.8 Zn 0.8 Ga 1.2 The temperature dependence of ionic conductivity of S4 is shown in Figure C3. 2.8 Zn 0.8 Ga 1.2 The ionic conductivity and activation energy of Na3ZnGaS4 at 25 °C are shown. The temperature dependence of ionic conductivity follows the Arrhenius law, and the activation energy was calculated from the Arrhenius plot. The ionic conductivity of Na3ZnGaS4 at 25 °C is 2.2 × 10 -7 S cm -1 , activation energy is 34 kJ mol -1 and showed ionic conductivity comparable to that of the previously reported Na3ZnGaS4. [2] The ionic conductivity of Na3ZnInS4 at 25 °C is 9.8 × 10 -8 S cm -1 , activation energy is 38 kJ mol -1 It was found that Na3ZnInS4 exhibits lower ionic conductivity than Na3ZnGaS4. 2.8 Zn 0.8 Ga 1.2 The ionic conductivity of S4 at 25 °C is 2.5 × 10 -5 S cm -1 , activation energy is 27 kJ mol -1 It was shown that the introduction of defects increases the ionic conductivity by two orders of magnitude at 25 °C and decreases the activation energy.

[0077] Example: Na 3-x Zn 1-x Al 1+x Preparation and evaluation of S4 [Synthesis] Na3Zn 1-x Al 1+x The preparation procedure for S4 is as follows. The starting materials, Na2S (NAGAO, 99.1%), S (Kojundo Chemical, 99.99%), Zn (Fujifilm Wako, 99.9%), and Al (Kojundo Chemical, 99.9%), were weighed out to a total of 0.75 g under dry argon, mixed in a mortar, and then placed in a 20 mm inner diameter carbon crucible. The mixture was heat-treated at 750 °C for 17 hours under a dry Ar atmosphere, followed by slow or rapid cooling to obtain the sample. Only the sample with x = 0 was prepared by slow cooling or rapid cooling. The samples with x = 0.1, 0.15, and 0.2 were prepared by rapid cooling only. For slow cooling, the temperature was lowered from 750 °C to room temperature over 6 hours. For rapid cooling, the carbon crucible at 750 °C was cooled by exposing it to room-temperature argon. The heating and cooling conditions and raw material composition are as follows. [Heating and cooling conditions] 1. RT → 750℃ (3 h) 2. 750℃ (17h) 3. 750 °C → RT (x = 0: rapid cooling and slow cooling, x = 0.1, 0.15, 0.2: rapid cooling) [Raw material composition] TIFF2025132791000001.tif5098

[0078] [Evaluation of structure and properties] Figure 1 shows the XRD patterns of Na3ZnAlS4 prepared by quenching and slow cooling. The Na3ZnAlS4 prepared by slow cooling and quenching showed patterns similar to those of Na3ZnGaS4 and Na3ZnInS4. From this, it can be concluded that Na3ZnAlS4 is similar to Na3ZnGaS4 [3] , Na3ZnInS4 [3]It was suggested that the Na3ZnAlS4 produced by slow cooling had a peak attributable to Na6ZnS4, while the Na3ZnAlS4 produced by rapid cooling did not. This suggests that the rapid cooling process suppressed the phase separation of Na6ZnS4. For Rietveld analysis, the XRD pattern of the rapidly cooled Na3ZnAlS4, which has fewer impurities, was used. Rietveld analysis was also performed using the tetragonal I41 / acd (No. 142), which is the same crystalline phase and space group as Na3ZnGaS4.

[0079] Figure 2 shows the pattern fitting results of the Rietveld analysis. Figures 3 and 4 show the structural parameters of Na3ZnAlS4 obtained from the Rietveld analysis, and Figure 5 shows the resulting crystal structure of Na3ZnAlS4. Note that the peaks at 18.3° to 18.82°, 24.5° to 24.84°, 26.0° to 27.0°, 38.3° to 39.0°, and 82.7° to 83.6° are impurity phases and were excluded from the analysis. The occupancies of the Na1, Na2, Zn, and Al sites were fixed to the occupancies of the starting composition. The thermal vibration parameters of the Na2 site were analyzed using anisotropic rather than isotropic thermal vibration parameters. This is because single-crystal structure analysis of similar crystals has shown that the Na2 site has large anisotropy. [4] . It was shown that Na3ZnAlS4 has a structure in which Zn and Al occupy half of the same site, with (Zn / Al)S4 tetrahedra sharing corners. Furthermore, the Na2 site exhibited a higher atomic displacement parameter value than the Na1 site. This suggests that, similar to Na3ZnGaS4, the sodium ion conductivity of the Na2 site is higher than that of the Na1 site.

[0080] Figure 6 shows Na 3-x Zn 1-x Al 1+xThe XRD pattern of S4 is shown below. A pattern similar to that of Na3ZnAlS4 was observed for all compositions. This suggests that increasing the amount of Al substitution does not change the crystalline phase or space group. When comparing XRD patterns measured at the same scan speed, the peak intensity decreased with increasing Al substitution. This is thought to be due to an increase in the amorphous component as the Al substitution increases. In addition, the peak attributable to the 431 plane shifted to higher angles as the Al substitution increased. This suggests that the lattice volume decreases with increasing Al substitution, and this decrease in lattice volume is thought to be due to the formation of a solid solution and the substitution of Zn for the Al site.

[0081] Figures 7, 10, and 13 show Na 3-x Zn 1-x Al 1+x The pattern fitting results of the Rietveld analysis of S4 (x = 0.1, 0.15, 0.2) are shown in Figures 8-9, 11-12, and 14-15. 3-x Zn 1-x Al 1+x The structural parameters obtained from the Rietveld analysis of S4 (x = 0.1, 0.15, 0.2) are shown below. Note that the peaks from 17.2° to 18.8° are impurity phases, so they were excluded from the analysis. In addition, the Rietveld analysis revealed that Na 2.8 Zn 0.8 Al 1.2 The thermal vibration parameters of Na2 in S4 are the conditions for anisotropic thermal vibration parameters. [5] (U 11, , U 22 , U 33 > 0, U 11 U 22 + U 22 U 33 + U 11 U 33 -U 12 2 -U 13 2 -U 23 2> 0, det U > 0) could not be obtained, so the occupancy of the Na1 site, Na2 site, and thermal vibration parameters were not refined.

[0082] Figure 16 shows the composition dependence of the a-axis length, Figure 17 shows the composition dependence of the c-axis length, and Figure 18 shows the composition dependence of the lattice volume. As the amount of Al substitution increased, the a-axis length decreased, the c-axis length increased, and the lattice volume decreased. This suggests that Zn was substituted with Al and a solid solution was formed.

[0083] Figure 19 shows the composition dependence of the Na1 site occupancy rate, and Figure 20 shows the composition dependence of the Na2 site occupancy rate. 2.8 Zn 0.8 Al 1.2 As mentioned above, for S4, the thermal vibration parameters of Na2 have not been refined, so the occupancies of Na1 and Na2 have not been refined. As the amount of Al substitution increases, the occupancies of the Na1 and Na2 sites decrease, suggesting that defects are introduced at the Na sites.

[0084] Figure 21 shows the results of a BVSE (Bond Valence Site Energy) analysis of Na3ZnAlS4. Figure 21 shows the energy isosurface at +0.77 eV relative to the ground energy value of Na3ZnAlS4. The Na1 site is colored red (dark), the Na2 site is colored orange (light), and the green (non-spherical) areas are the conduction paths of sodium ions. This suggests that the Na2 site has high ionic conductivity and the Na1 site has low sodium ion conductivity. This suggests that introducing defects into the Na2 site is effective for ionic conduction, but introducing defects into the Na1 site is not effective for improving ionic conductivity.

[0085] Figure 22 shows Na 3-x Zn 1-x Al 1+x The temperature dependence of ionic conductivity of S4 is shown in Figure 23. 3-x Zn 1-x Al 1+xThe ionic conductivity and activation energy of Na3ZnAlS4 at 25 °C are shown. The temperature dependence of ionic conductivity follows the Arrhenius law, and the activation energy was calculated from the Arrhenius plot. The ionic conductivity of Na3ZnAlS4 at 25 °C is 3.8 × 10 -7 S cm -1 , activation energy is 37 kJ mol -1 It was. 3-x Zn 1-x Al 1+x S4 showed high ionic conductivity equal to or higher than that of Na3ZnMS4 (M = In, Ga). 3-x Zn 1-x Al 1+x S4(x = 0.1, 0.15, 0.2) 10 at 25 °C -6 S cm -1 It was shown that the introduction of defects increases the room temperature ionic conductivity by about one order of magnitude. 3-x Zn 1-x Al 1+x Among S4, Na exhibited the highest room temperature ionic conductivity and the lowest activation energy. 2.9 Zn 0.9 Al 1.1 The ionic conductivity of S4 at 25 °C is 4.5 × 10 -6 S cm -1 and the activation energy is 32 kJ mol -1 It was. 2.85 Zn 0.85 Al 1.15 S4, Na 2.8 Zn 0.8 Al 1.2 S4 is Na 2.9 Zn 0.9 Al 1.1 It showed lower room temperature ionic conductivity than S4. This is thought to be due to the fact that the defects in the Na2 site, which are the sodium ion conduction pathways, remain almost unchanged and the lattice volume is reduced. 3-x Zn 1-x Al 1+x The highest ionic conductivity among S4 was observed in Na 2.9 Zn 0.9 Al 1.1 The structural stability of S4 against moisture was evaluated.

[0086] Figure 24 shows the NaCl concentration after 30 minutes of exposure to air with a relative humidity of 70%. 2.9 Zn 0.9 Al 1.1 The XRD pattern of S4 is shown. 2.9 Zn 0.9 Al 1.1 A pattern attributed to S4 was observed, and some peaks attributed to NaSH were also observed. 2.9 Zn 0.9 Al 1.1 It was suggested that S4 has high moisture resistance.

[0087] Figure 25 shows the Na before exposure to air. 2.9 Zn 0.9 Al 1.1 S4, Na after 30 min exposure to air at 70% relative humidity 2.9 Zn 0.9 Al 1.1 The Raman spectrum of S4 is shown. After exposure, the SH band is visible on the high wavenumber side. - A peak was observed that could be attributed to [6] Also, 100 to 500 cm -1 The peak of NaSH did not change between the samples before and after exposure. This suggests that there was no change in the local structure before and after the exposure test. Furthermore, the generation of NaSH suggested by the XRD pattern and Raman spectrum was due to the Na 2.9 Zn 0.9 Al 1.1 It is thought that this was formed by hydrolysis of impurities with low moisture resistance in the S4 sample. 2.9 Zn 0.9 Al 1.1 It was suggested that S4 is stable against moisture. [7] It has been reported that the high chemical stability of Na3ZnGaS4 is due to the high chemical stability of the structure in which (Zn / Ga)S4 units are linked in a chain shape with corner sharing. 2.9 Zn 0.9 Al 1.1The high moisture resistance of S4 is due to the high chemical stability of the structure in which (Zn / Al)S4 units are connected in a chain shape with corner sharing, and it is thought that it is also stable against moisture.

[0088] <References> [1] S. Han, JY Seo, WB Park, AB Ikhe, SY Choi, SC Han, KS Sohn and M. Pyo, J. Mater. Chem. A, 10 (2022) 25039-25046. [2] S. Balijapelly, Q. Zhang, P. Sandineni, A. Adhikary, S. Mohapatra, S. Sundaramoorthy, N. Gerasimchuck, AV Chernatynskiy and A. Choudhury, ACS Appl. Energy Mater., 4 (2021) 7942-7951. [3] R. Chen, X. Wu and Z. Su, Dalton Trans., 47 (2018) 15538-15544. [4] S. Mohapatra, A. Adhikary, K. Ghosh and A. Choudhur, Inorg. Chem., 56 (2017), 7650-7656. [5] Izumi Nakai and Fujio Izumi, eds., Practical Application of Powder X-ray Analysis, 3rd Edition, Asakura Publishing, (2021) 154. [6] P. Bazylewski, R. Divigalpitiyab and G. Fanchini, RSC Adv., 7 (2017) 2964-2970. [7]EH Hwang, JY Seo, WB Park, SY Kang, KS Sohn, and M. Pyo, J. Power Sources, 581 (2023) 233511. [Brief explanation of the drawings]

[0089] [Figure C1] XRD patterns of Na3ZnMS4 (M = In, Ga) and Na2.8Zn0.8Ga1.2S4. The right image is an enlargement of the left image. [Figure C2] Temperature dependence of ionic conductivity of Na3ZnMS4 (M = In, Ga) and Na2.8Zn0.8Ga1.2S4. [Figure C3] Ionic conductivity and activation energy of Na3ZnMS4 (M = In, Ga) and Na2.8Zn0.8Ga1.2S4 at 25 °C. [Figure 1] XRD pattern of Na3ZnAlS4. [Figure 2] Pattern fitting results from Rietveld analysis of Na3ZnAlS4. [Figure 3] Crystal data and atomic coordinates of Na3ZnAlS4. [Figure 4] Anisotropic displacement parameters of Na3ZnAlS4 (unit: Å2). [Figure 5] Crystal structure of Na3ZnAlS4. [Figure 6] XRD pattern of Na3-xZn1-xAl1+xS4. The right image is an enlargement of the left image. [Figure 7] Pattern fitting results by Rietveld analysis of Na2.9Zn0.9Al1.1S4. [Figure 8] Crystal data and atomic coordinates of Na2.9Zn0.9Al1.1S4. [Figure 9] Anisotropic displacement parameters of Na2.9Zn0.9Al1.1S4 (unit: Å2). [Figure 10] Pattern fitting results by Rietveld analysis for Na2.85Zn0.85Al1.15S4. [Figure 11] Crystal data and atomic coordinates of Na2.85Zn0.85Al1.15S4. [Figure 12] Anisotropic displacement parameters of Na2.85Zn0.89Al1.15S4 (unit: Å2). [Figure 13]Pattern fitting results by Rietveld analysis of Na2.8Zn0.8Al1.2S4. [Figure 14] Crystal data and atomic coordinates of Na2.8Zn0.8Al1.2S4. [Figure 15] Anisotropic displacement parameters of Na2.8Zn0.8Al1.2S4 (unit: Å2). [Figure 16] Composition dependence of the lattice constant a in Na3-xZn1-xAl1+xS4. [Figure 17] Composition dependence of the lattice constant c in Na3-xZn1-xAl1+xS4. [Figure 18] Composition dependence of lattice volume in Na3-xZn1-xAl1+xS4. [Figure 19] Composition dependence of the SOF (site occupancy factor) of Na1 in Na3-xZn1-xAl1+xS4. [Figure 20] Composition dependence of the SOF (site occupancy factor) of Na2 in Na3-xZn1-xAl1+xS4. [Figure 21] Results of BVSE (Bond Valence Site Energy) analysis of Na3ZnAlS4. [Figure 22] Temperature dependence of ionic conductivity of Na3-xZn1-xAl1+xS4. [Figure 23] Ionic conductivity and activation energy of Na3-xZn1-xAl1+xS4 at 25 °C. [Figure 24] XRD patterns of Na2.9Zn0.9Al1.1S4 before and after exposure to air at 70% relative humidity. [Figure 25] Raman spectra of Na2.9Zn0.9Al1.1S4 before and after exposure to air at 70% relative humidity.

Claims

1. formula: Na ３－ｘ Zn １－ｘ Al １＋ｘ S ４ [In the formula, x is 0 or more and 0.5 or less.] Sulfides represented by:

2. The sulfide according to claim 1, wherein x is 0.25 or less.

3. The sulfide according to claim 1 or 2, wherein x is 0.01 or more.

4. The sulfide according to claim 1 or 2, which is a solid electrolyte for a sodium ion battery.

5. The sulfide according to claim 1 or 2, which is a solid electrolyte for an all-solid-state sodium ion battery.

6. A battery component comprising the sulfide according to claim 1 or 2.

7. The battery component according to claim 6 , wherein the battery component is a negative electrode.

8. The battery component according to claim 6 , wherein the battery component is a positive electrode.

9. The battery element according to claim 6 , wherein the battery element is an electrolyte layer.

10. The battery component according to claim 6 , wherein the battery component is a solid electrolyte layer.

11. A battery comprising the battery component of claim 6 .

12. formula: Na ３－ｘ Zn １－ｘ Al １＋ｘ S ４ [In the formula, x is 0 or more and 0.5 or less.] A method for producing a sulfide represented by the formula: Na ２ S ｎ (n is 1 or more and 10 or less), a raw material mixing step of mixing S, Zn, and Al to obtain a mixture; a heating step of heating the mixture to obtain a heat-treated product; and a cooling step of cooling the heat-treated product A manufacturing method comprising:

13. The method according to claim 12, wherein the heating step is carried out at atmospheric pressure.

14. The method according to claim 12 or 13, wherein the heating step is carried out at 500°C or higher and 1000°C or lower.

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