Sulfide solid electrolyte

Abstract

When X-ray diffraction measurement using CuKα rays is performed at room temperatures, let that the diffraction intensity of the strongest peak in a diffraction pattern is defined as IX, that the diffraction intensity of the peak at 2θ=25.50°±0.5° is defined as IA, and the diffraction intensity of the peak at 2θ= 32.46°±0.5° is defined as IB, this sulfide solid electrolyte is characterized in that the peak intensity ratio IA / IX which is the ratio of IA to IX is 0.5 or less, and that the peak intensity ratio IB / IXI which is the ratio of IB to IX is 0.5 or less.

Description

Sulfide solid electrolyte

[0001] This invention relates to a sulfide solid electrolyte suitable for use in, for example, all-solid-state batteries, etc. This application claims priority based on Japanese Patent Application No. 2024-089872, filed on June 3, 2024, the contents of which are incorporated herein by reference.

[0002] Currently available lithium-ion batteries use flammable organic electrolytes as the electrolyte material, necessitating the installation of safety devices to suppress temperature rises in the event of a short circuit, as well as improvements to the structure and materials to prevent short circuits. In contrast, all-solid-state lithium-ion batteries use solid electrolytes, simplifying the safety devices associated with flammable organic electrolytes and offering superior manufacturing costs and productivity. In addition, stacking batteries in a bipolar configuration in series within the same cell also offers the potential for further development, enabling higher voltages and higher output.

[0003] As a solid electrolyte suitable for all-solid-state batteries, sulfide solid electrolytes with high ionic conductivity are known, as disclosed in Patent Document 1. However, sulfide solid electrolytes have the disadvantage of easily reacting with moisture in the atmosphere, generating toxic hydrogen sulfide gas while also producing oxides that reduce Li ion conductivity. This has led to increased costs associated with managing the dew point temperature during the production of solid electrolytes and all-solid-state batteries, as well as the need for safety measures regarding the generation of hydrogen sulfide gas.

[0004] Therefore, several techniques for suppressing the generation of hydrogen sulfide gas are proposed in Patent Documents 2 to 4. Furthermore, Patent Document 5 describes a method for producing a sulfide solid electrolyte by heat treating a raw material composition containing elemental sulfur or a sulfur compound.

[0005] International Publication No. 2011 / 118801 Japanese Patent Application Laid-Open No. 2019-160625 International Publication No. 2021 / 029315 International Publication No. 2021 / 117869 Japanese Patent Application Laid-Open No. 2022-022955

[0006] Meanwhile, Patent Documents 2 to 4 disclose technologies for suppressing the amount of hydrogen sulfide gas generated, but this results in a problem of reduced Li ion conductivity, making it impossible to construct a high-output solid-state battery. That is, Patent Documents 2 to 4 make it difficult to simultaneously achieve high Li ion conductivity, for example, exceeding 5.0 mS / cm, and suppress the amount of hydrogen sulfide gas generated. Patent Document 5 also poses the issue of the generation of by-products (impurity phases) other than the desired sulfide solid electrolyte, which adversely affect the generation of hydrogen sulfide gas and the reduction in ionic conductivity.

[0007] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a sulfide solid electrolyte that has high Li ion conductivity while suppressing the amount of hydrogen sulfide gas generated by reaction with moisture in the atmosphere.

[0008] In order to solve the above problems, the present inventors conducted extensive research and found that, when measuring an X-ray diffraction pattern of an LGPS-type sulfide solid electrolyte, compounds having a diffraction peak at 2θ = 25.50° ± 0.5° or 2θ = 32.46° ± 0.5° cause the generation of hydrogen sulfide gas and a decrease in ionic conductivity. Therefore, the inventors discovered that by reducing the content of at least one or both of these compounds in an LGPS-type sulfide solid electrolyte, it is possible to provide a sulfide solid electrolyte that has high Li ion conductivity while suppressing the amount of hydrogen sulfide gas generated by reaction with moisture in the air.

[0009] The present invention has been made based on the above findings, and the sulfide solid electrolyte of the first aspect of the present invention has a diffraction intensity of the strongest peak in a diffraction pattern of I when X-ray diffraction measurement using CuKα radiation is performed at room temperature. Ｘ The diffraction intensity of the peak at 2θ = 25.50° ± 0.5° is I Ａ The diffraction intensity of the peak at 2θ = 32.46° ± 0.5° is I Ｂ As, I Ｘ I against Ａ Peak intensity ratio I Ａ / I Ｘ is 0.5 or less, and IＸ I against Ｂ Peak intensity ratio I Ｂ / I Ｘ is 0.5 or less.

[0010] According to the sulfide solid electrolyte of aspect 1 of the present invention, when the X-ray diffraction pattern is measured using CuKα rays at room temperature, the diffraction intensity of the strongest peak in the X-ray diffraction pattern is I Ｘ The diffraction intensity of the peak at 2θ = 25.50° ± 0.5° is I Ａ The diffraction intensity of the peak at 2θ = 32.46° ± 0.5° is I Ｂ As, I Ｘ I against Ａ Peak intensity ratio I Ａ / I Ｘ is 0.5 or less, and I Ｘ I against Ｂ Peak intensity ratio I Ｂ / I Ｘ Therefore, the content of the compound having a diffraction peak at 2θ=32.46°±0.5° and the content of the compound having a diffraction peak at 2θ=32.46°±0.5° are sufficiently reduced, making it possible to suppress the generation of hydrogen sulfide gas and to suppress the decrease in ionic conductivity.

[0011] The sulfide solid electrolyte of the second aspect of the present invention is the sulfide solid electrolyte of the first aspect of the present invention, which is the same as the sulfide solid electrolyte of the first aspect of the present invention, except that LGPS (Li １０ GeP ２ S １２ ) type crystal structure.

[0012] The sulfide solid electrolyte of aspect 2 of the present invention has an LGPS-type crystal structure belonging to the space group P42 / nmc, and is therefore particularly suitable as a solid electrolyte for use in all-solid-state batteries and the like.

[0013] According to an aspect of the present invention, it is possible to provide a sulfide solid electrolyte having high Li ion conductivity while suppressing the amount of hydrogen sulfide gas generated by reaction with moisture in the atmosphere.

[0014] 1 is a flow chart showing an example of a method for producing a sulfide solid electrolyte according to an embodiment of the present invention. 2 is a diagram showing an example of the measurement results of an X-ray diffraction pattern (XRD pattern) of the sulfide solid electrolyte according to Example 1 of the present invention.

[0015] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Note that the following embodiments are specifically described to provide a better understanding of the gist of the invention, and do not limit the present invention unless otherwise specified.

[0016] The sulfide solid electrolyte according to this embodiment is a sulfide used as a solid electrolyte for constituting, for example, an all-solid-state battery. Sulfide solid electrolyte materials have high ionic conductivity, are non-flammable, and are highly safe, and are therefore applied to electric vehicles and the like.

[0017] In the sulfide solid electrolyte according to this embodiment, when the X-ray diffraction pattern is measured at room temperature using CuKα rays, the diffraction intensity of the strongest peak in the X-ray diffraction pattern is I Ｘ The diffraction intensity of the peak at 2θ = 25.50° ± 0.5° is I Ａ The diffraction intensity of the peak at 2θ = 32.46° ± 0.5° is I Ｂ As, I Ｘ I against Ａ Peak intensity ratio I Ａ / I Ｘ is 0.5 or less, and I Ｘ I against Ｂ Peak intensity ratio I Ｂ / I Ｘ In this embodiment, the notation "a±b" indicates a numerical range of not less than "a-b" and not more than "a+b".

[0018] That is, in the sulfide solid electrolyte according to this embodiment, the above-mentioned peak intensity ratio I Ａ / I Ｘ , and the peak intensity ratio I Ｂ / I ＸBoth of these are 0.5 or less, and the content of both the compound having a diffraction peak at 2θ=25.50°±0.5° and the compound having a diffraction peak at 2θ=32.46°±0.5° is considered to be sufficiently reduced. The diffraction peak at 2θ=25.50°±0.5° is a diffraction peak of crystalline β-Li. ３ P.S. ４ It is presumed that this is due to the crystalline β-Li ３ P.S. ４ The electrical conductivity of β-Li is lower than that of the target sulfide solid electrolyte. ３ P.S. ４ At the same time, amorphous Li ３ P.S. ４ It is possible that amorphous Li is being produced. ３ P.S. ４ It is estimated that the amount of hydrogen sulfide generated increases when Li is contained. ７ P.S. ６ It is presumed to be derived from Li ７ P.S. ６ When the material contains , the electrical conductivity decreases and the amount of hydrogen sulfide generated increases. Ａ / I Ｘ is preferably 0.50 or less, more preferably 0.25 or less, and most preferably 0. Ｂ / I Ｘ is preferably 0.50 or less, more preferably 0.25 or less, and most preferably 0. Ｂ / I Ｘ than the peak intensity ratio I Ａ / I Ｘ has a greater contribution in terms of improving electrical conductivity and reducing the amount of hydrogen sulfide generated, so the peak intensity ratio I Ｂ / I Ｘ than the peak intensity ratio I Ａ / I Ｘ is preferably smaller.

[0019] The sulfide solid electrolyte of this embodiment is LGPS (Li １０ GeP２ S １２ When the X-ray diffraction pattern is measured at room temperature using CuKα radiation, the following diffraction peaks of formulas (C1) to (C6) are detected: 2θ = 17.38° ± 0.5° (C1) 2θ = 20.18° ± 0.5° (C2) 2θ = 20.44° ± 0.5° (C3) 2θ = 23.96° ± 0.5° (C4) 2θ = 26.96° ± 0.5° (C5) 2θ = 29.58° ± 0.5° (C6)

[0020] The sulfide solid electrolyte of this embodiment is composed of an LGPS phase and impurity components. The impurity components are crystalline phases having a crystal structure other than the LGPS type, amorphous phases, and unavoidable impurities, and examples thereof include the aforementioned crystalline phases having a diffraction peak at 2θ=25.50°±0.5° and a diffraction peak at 2θ=32.46°±0.5°. The overall composition of the sulfide solid electrolyte of this embodiment is preferably represented by the following chemical formula (1): Li ａ Ge ｂ P ｃ S ｄ (1) However, the following conditions are satisfied: 10.00≦a≦10.35, 1.00≦b≦1.35, 1.95≦c≦2.05, and 12.00≦d≦13.60. Generally, the composition of chemical substances is measured by a method in which the chemical substances are dissolved in an acid aqueous solution and quantitatively analyzed by ICP atomic emission spectroscopy or X-ray photoelectron spectroscopy. However, when the sulfide solid electrolyte of this embodiment is dissolved in an acid aqueous solution, sulfur is converted into H ２ S is released. Furthermore, it is difficult to completely dissolve components other than sulfur. For this reason, it is difficult to accurately quantitatively analyze the composition of the sulfide solid electrolyte using ICP atomic emission spectroscopy. Furthermore, when the composition of the sulfide solid electrolyte of this embodiment is quantitatively analyzed using X-ray photoelectron spectroscopy in an environment not exposed to air, the measurement results contain an error of 2 to 3%, making it difficult to accurately quantitatively analyze the composition. Therefore, at this time, it is difficult to accurately identify the composition of the sulfide solid electrolyte of this embodiment. For this reason, considering the composition of the raw materials used in the manufacturing method described below and the evaporation of sulfur during the manufacturing process, it is estimated that the overall composition of the sulfide solid electrolyte satisfies the above-mentioned chemical formula (1).

[0021] The composition of the LGPS phase is preferably represented by the following chemical formula (2): １２.００－ｘ Ge ３．００－ｘ P ｘ S １２.００ (2) However, 1.65≦x≦2.00 is satisfied. By having the composition of chemical formula (2), the LGPS phase can maintain the LGPS type crystal structure. If the value of x is outside the above range, the LGPS type crystal structure cannot be maintained and impurity components are mainly contained, which is not preferable. The composition of the LGPS phase is Li １０ GeP ２ S １２ It is more preferable that (x = 2.00). When almost no impurity components are contained, the overall composition of the sulfide solid electrolyte is substantially represented by chemical formula (2). For the reasons described above, it is difficult to accurately identify the overall composition of the sulfide solid electrolyte and the composition of the LGPS phase. From the composition of the raw materials and the measurement results of the XRD pattern, it is estimated that the composition of the LGPS phase is represented by the above-mentioned chemical formula (2).

[0022] Next, an example of a method for producing a sulfide solid electrolyte according to this embodiment will be described with reference to the flow diagram of Fig. 1. As shown in Fig. 1, the production method according to this embodiment includes a raw material mixing step S01 and a production step S02.

[0023] (Raw material mixing step S01) First, raw materials containing the elements constituting the sulfide solid electrolyte are mixed to obtain a mixed raw material. Here, in this embodiment, the blending amount of the P element in the mixed raw material is set to the stoichiometric amount of the P element in the LGPS-type crystal (Li １０ GeP ２ S １２ The P content in the mixed raw material is set to a range of -2.5 mol % or more and 2.0 mol % or less relative to the P composition ratio (2.00 in the mixed raw material). By setting the P content in the mixed raw material in this manner, it is possible to suppress the production of a compound having a diffraction peak at 2θ = 25.50° ± 0.5° and a compound having a diffraction peak at 2θ = 32.46° ± 0.5° in the production step S02. In this way, the amount of P in the mixed raw material affects the amount of impurity components in the produced sulfide solid electrolyte.

[0024] In this embodiment, elemental sulfur is preferably used as the raw material. In addition, in order to utilize the solid-liquid reaction between each raw material and liquid sulfur to generate the sulfide solid electrolyte (LGPS phase), the stoichiometric composition (Li １０ GeP ２ S １２ An excess amount of elemental sulfur exceeding the S composition ratio of 12.00 in the above formula (S) may be added to the raw material mixture. Of the raw materials, only elemental sulfur evaporates upon heating in the production step S02 described below, and a portion of the elemental sulfur is released outside the system. For this reason, the composition of the final product (the overall composition of the sulfide solid electrolyte) may deviate from the composition of the raw material mixture in terms of the amount of elemental sulfur. However, an amount of elemental sulfur that results in the composition of the above-described chemical formula (2) is consumed to produce the LGPS phase, and an excess amount of sulfur from the composition of chemical formula (2) evaporates. Furthermore, in order to promote element diffusion and chemical reaction in the subsequent production step S02, each raw material and the excess amount of elemental sulfur are preferably in the form of powder or granules (powder-like powder, particulate granules, or an aggregate of powder and granules), and powder is more preferred.

[0025] Elemental sulfur refers to sulfur that does not contain elements other than sulfur, except for inevitable impurities. Unless otherwise specified, in other descriptions of this embodiment, each raw material may contain inevitable impurities. Furthermore, the elemental sulfur to be added may be any of sulfur allotropes, such as α sulfur (orthorhombic sulfur), β sulfur (monoclinic sulfur), γ sulfur (monoclinic sulfur), and rubber sulfur, or may contain multiple allotropes.

[0026] The mixing method in the raw material mixing step S01 is not particularly limited as long as it can uniformly mix the raw materials, and examples of various existing methods include a mortar, a general mixer, a blender, a ball mill, a bead mill, a vibration mill, a V-type mixer, etc. Furthermore, instead of the general mixing process, mechanical milling may be performed using a planetary ball mill, a vibration mill, a ball mill, etc.

[0027] Furthermore, when the raw materials contain sulfides or the like, the mixing treatment in the raw material mixing step S01 is preferably carried out in a gas atmosphere that does not react with the raw materials. Therefore, it is preferable to carry out the treatment in an inert atmosphere such as nitrogen, argon, or other rare gases. Furthermore, it is preferable that the atmospheric gas used does not contain moisture or oxygen gas, and in particular, the moisture content in the atmospheric gas is preferably 500 ppm or less, more preferably 100 ppm or less, and even more preferably 10 ppm or less. By keeping the moisture content in the atmospheric gas within this range, oxidation due to moisture is suppressed, making it possible to produce a high-quality sulfide solid electrolyte.

[0028] (Production Step S02) In the production step S02, the mixed raw materials placed in a firing container such as a crucible or a sagger are heated to produce a sulfide solid electrolyte. As for the material of the firing container, it is preferable that the inner wall of the container is made of a material that is not easily reacted with the melt, such as elemental sulfur or sulfides, in other words, a material that is not easily corroded by sulfurization, such as alumina, zirconia, carbon, or silicon carbide.

[0029] The heating temperature in the generation step S02 is preferably 400°C or higher, more preferably 450°C or higher, and even more preferably 500°C or higher. On the other hand, the heating temperature is preferably 1000°C or lower, and more preferably 650°C or higher. The holding time at the heating temperature is preferably 30 minutes or longer, and more preferably 60 minutes or longer. On the other hand, the holding time at the heating temperature is preferably 12 hours or shorter, and more preferably 6 hours or shorter.

[0030] Furthermore, the heat treatment in the production step S02 is preferably carried out in a gas atmosphere that does not react with the mixed raw materials, the intermediate product, or the sulfide solid electrolyte. Therefore, it is preferably carried out in an inert atmosphere such as nitrogen, argon, or other rare gases. Furthermore, it is preferable that the atmospheric gas used does not contain moisture or oxygen gas. In particular, the moisture content in the atmospheric gas is preferably 500 ppm or less, more preferably 100 ppm or less, and even more preferably 10 ppm or less. By keeping the moisture content in the atmospheric gas within this range, reaction with moisture is suppressed, making it possible to produce a high-quality sulfide solid electrolyte.

[0031] According to the sulfide solid electrolyte of the present embodiment having the above-described configuration, when the X-ray diffraction pattern is measured at room temperature using CuKα rays, the diffraction intensity of the strongest peak in the X-ray diffraction pattern is I Ｘ The diffraction intensity of the peak at 2θ = 25.50° ± 0.5° is I Ａ The diffraction intensity of the peak at 2θ = 32.46° ± 0.5° is I Ｂ As, I Ｘ I against Ａ Peak intensity ratio I Ａ / I Ｘ , and I Ｘ I against Ｂ Peak intensity ratio I Ｂ / I Ｘ Therefore, the contents of both the compound having a diffraction peak at 2θ=25.50°±0.5° and the compound having a diffraction peak at 2θ=32.46°±0.5° are sufficiently reduced, which makes it possible to suppress the generation of hydrogen sulfide gas and to suppress the decrease in ionic conductivity.

[0032] In addition, the sulfide solid electrolyte of this embodiment is LGPS (Li １０ GeP ２ S １２When the solid electrolyte contains an LGPS phase having a crystalline structure of the crystalline type 1, and when an X-ray diffraction pattern thereof is measured at room temperature using CuKα radiation, peaks of the above formulas (C1) to (C6) are detected as diffraction peaks, the solid electrolyte is particularly suitable as a solid electrolyte to be used in an all-solid-state battery or the like.

[0033] Although one embodiment of the present invention has been described above, the present invention is not limited to this and can be modified as appropriate within the scope of the technical requirements of the invention.

[0034] A confirmation experiment conducted to confirm the effectiveness of the present invention will be described.

[0035] As a raw material, Li ２ S, Ge, P, and S were prepared, weighed to a predetermined ratio, and mixed in a mortar. At this time, the amount of P element in the mixed raw material was determined to be the stoichiometric amount (Li １０ GeP ２ S １２ The ratio (mol %) of the total sulfide content in the sulfide oxide was adjusted to the ratio (mol %) shown in Table 1 relative to the P composition ratio (2.00 in the sulfide oxide composition). The mixed raw material was placed in an alumina firing container and charged into a firing furnace. The raw material was then fired in an Ar atmosphere at a heating temperature of 550°C for a holding time of 6 hours. In this way, sulfide solid electrolytes of the present invention and comparative examples were produced.

[0036] The X-ray diffraction pattern of the obtained sulfide solid electrolyte was measured using CuKα radiation (XRD pattern measurement). The ionic conductivity of the sulfide solid electrolyte was also measured. Furthermore, the amount of hydrogen sulfide generated was evaluated. The methods for measuring the XRD pattern, measuring the ionic conductivity, and evaluating the amount of hydrogen sulfide generated are described below.

[0037] <XRD Pattern Measurement> The XRD pattern was measured using a Bruker XRD device "D8 ADVANCE," with θ-2θ measurement performed in the range of 10°≦2θ≦55°, with a step width of 0.01° and an accumulation time of 1.2 seconds per step. The measurement sample was prepared in a glove box under an argon atmosphere, and the solid electrolyte member was pulverized in an agate mortar and sealed in a sealable measurement cell, and powder X-ray diffraction measurement was performed while maintaining a state where it was not exposed to the atmosphere. The measurement results of the XRD pattern for Invention Example 1 are shown in FIG. 2.

[0038] <Measurement of Ionic Conductivity> Each of the solid electrolytes obtained as described above was taken out into a glove box in an argon atmosphere and then crushed in an agate mortar. 0.200 g was weighed and filled into a ceramic insulating tube (cylindrical with an inner diameter of 10.2 mm) at an applied pressure of 30 MPa, and the insulating tube was sealed with a stainless steel ionic conductivity measurement cell. The ionic conductivity (mS / cm) was then measured by the AC impedance method using a Biologic Corporation "Potentio / Galvanostat SP-300" measuring device at a measurement temperature of 25°C and a measurement frequency of 1 Hz to 1 MHz.

[0039] <Measurement of the amount of hydrogen sulfide gas generated> 10 mg of a measurement sample and a digital hydrogen sulfide meter were placed in a glove box with a dew point of −30° C., and these were then placed in a 1 L sealed container inside the glove box and allowed to stand, and the hydrogen sulfide concentration was measured after 1 hour.

[0040]

[0041] In Comparative Example 1, when the X-ray diffraction pattern was measured at room temperature using CuKα rays, the diffraction intensity of the strongest peak in the X-ray diffraction pattern was I Ｘ The diffraction intensity of the peak at 2θ = 25.50° ± 0.5° is I Ａ As, I Ｘ I against Ａ Peak intensity ratio I Ａ / I Ｘ was 0.627, the ionic conductivity was low at 4.8 mS / cm, and the amount of hydrogen sulfide generated was high at 36.3 ppm.

[0042] In Comparative Example 2, when the X-ray diffraction pattern was measured at room temperature using CuKα rays, the diffraction intensity of the strongest peak in the X-ray diffraction pattern was I Ｘ The diffraction intensity of the peak at 2θ = 32.46° ± 0.5° is I Ｂ As, I Ｘ I against Ｂ Peak intensity ratio I Ｂ / I Ｘ The ionic conductivity was low at 7.2 mS / cm, and the amount of hydrogen sulfide generated was high at 14.9 ppm.

[0043] In Comparative Example 3, when the X-ray diffraction pattern was measured at room temperature using CuKα rays, the diffraction intensity of the strongest peak in the X-ray diffraction pattern was I Ｘ The diffraction intensity of the peak at 2θ = 32.46° ± 0.5° is I Ｂ As, I Ｘ I against Ｂ Peak intensity ratio I Ｂ / I Ｘ The ionic conductivity was low at 6.8 mS / cm, and the amount of hydrogen sulfide generated was high at 16.3 ppm.

[0044] In contrast, in Examples 1 to 3 of the present invention, when the X-ray diffraction pattern was measured at room temperature using CuKα radiation, the diffraction intensity of the strongest peak in the X-ray diffraction pattern was I Ｘ The diffraction intensity of the peak at 2θ = 25.50° ± 0.5° is I Ａ The diffraction intensity of the peak at 2θ = 32.46° ± 0.5° is I Ｂ As, I Ｘ I against Ａ Peak intensity ratio I Ａ / I Ｘ is 0.5 or less, and I Ｘ I against Ｂ Peak intensity ratio I Ｂ / I Ｘ The ionic conductivity was 9.3 mS / cm or more, which was sufficiently higher than that of the comparative example, and the amount of hydrogen sulfide generated was smaller than that of the comparative example.

[0045] As a result of the above confirmatory experiments, it was confirmed that the present invention can provide a sulfide solid electrolyte having high Li ion conductivity while suppressing the amount of hydrogen sulfide gas generated by reaction with moisture in the atmosphere.

[0046] The sulfide solid electrolyte of this embodiment is suitable for use in all-solid-state batteries and the like.

Claims

When X-ray diffraction measurement using CuKα radiation was performed at room temperature, the diffraction intensity of the strongest peak in the diffraction pattern was determined as I Ｘ The diffraction intensity of the peak at 2θ = 25.50° ± 0.5° is I Ａ The diffraction intensity of the peak at 2θ = 32.46° ± 0.5° is I Ｂ As, I Ｘ I against Ａ Peak intensity ratio I Ａ / I Ｘ is 0.5 or less, and I Ｘ I against Ｂ Peak intensity ratio I Ｂ / I Ｘ A sulfide solid electrolyte characterized in that: LGPS (Li) belonging to the space group P42 / nmc １０ GeP ２ S １２ 2. The sulfide solid electrolyte according to claim 1, characterized in that it has a crystalline structure of the ZnO-type.

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