Sulfide solid electrolyte and preparation method and application thereof

Abstract

The invention provides a sulfide solid electrolyte and a preparation method and application thereof. The preparation method comprises the following steps: providing a raw material, wherein the raw material contains required elements in a preset molar ratio for synthesizing the sulfide solid electrolyte; the raw materials and the liquid metal are subjected to nanoscale mixing, and a mixed material is obtained; and sintering the mixed material, so that the mixed material reacts to generate the sulfide solid electrolyte. The preparation method provided by the invention does not need to adopt an organic solvent, the obtained product has high purity and no carbon residue, and the problem that carbon residue is introduced by a solvent mixing method in the prior art can be solved. Meanwhile, the preparation method provided by the invention is simple in process, low in equipment requirement and suitable for industrialization, and can solve the problem that a solid-phase ball milling method in the prior art is not easy to amplify.

Description

Technical Field

[0001] The present invention belongs to the technical field of secondary batteries, and in particular relates to a sulfide solid electrolyte and a preparation method and application thereof. Background Art

[0002] Solid-state batteries, as the next generation of lithium-ion batteries and a viable option for energy storage, are currently attracting significant attention from both the business and academic communities. The application of solid-state batteries inevitably requires the full development of solid-state electrolytes.

[0003] Currently, sulfide solid electrolytes (LPSCs) are considered one of the most promising solid electrolytes due to their high ionic conductivity, low electronic conductivity, and moderate hardness. Current methods for preparing LPSCs can be divided into two types: solid-phase ball milling and solvent mixing. The solid-phase ball milling method requires the use of a ball mill, which requires repeated disassembly of the equipment and makes scale-up difficult. The solvent mixing method typically requires the use of organic solvents, which introduce large amounts of carbon residues, which can degrade the performance of LPSCs. Therefore, it is necessary to develop a new method for preparing sulfide solid electrolytes to address existing problems. Summary of the Invention

[0004] In order to solve all or part of the above technical problems, the present invention provides the following technical solutions:

[0005] One of the objects of the present invention is to provide a method for preparing a sulfide solid electrolyte, comprising:

[0006] Providing a raw material containing a predetermined molar ratio of required elements for synthesizing a sulfide solid electrolyte;

[0007] Mixing the raw material with liquid metal at the nanoscale to obtain a mixed material;

[0008] The mixed material is sintered to react and generate a sulfide solid electrolyte.

[0009] The present application provides a novel liquid-phase method for preparing sulfide solid electrolytes (LPSCs), which uses liquid metal instead of organic solvents and uses liquid metal to grind and mix the raw materials to promote their nanoscale mixing. This method can eradicate the carbon residue problem introduced by organic solvents at the source.

[0010] In some embodiments, the preparation method specifically includes: mixing the raw material with a low-melting-point metal, adjusting the temperature to a metal liquefaction temperature to liquefy the low-melting-point metal to form the liquid metal, and performing the nanoscale mixing at the metal liquefaction temperature to obtain the mixed material, wherein the melting point of the low-melting-point metal is below 100°C. The "metal liquefaction temperature" as used herein refers to the temperature at which the low-melting-point metal can liquefy and maintain a liquid state.

[0011] In some embodiments, the liquid metal includes at least one of liquid mercury, cesium, and rubidium, that is, the low-melting-point metal includes at least one of liquid mercury, cesium, and rubidium.

[0012] In some embodiments, the content of the liquid metal in the mixture is 60 wt % to 80 wt %.

[0013] In some embodiments, the metal liquefaction temperature is 20-300°C.

[0014] In some embodiments, the temperature is increased to the metal liquefaction temperature at a rate of 2-10° C. / min.

[0015] In some embodiments, the nanoscale mixing comprises: mixing the raw materials with the low-melting-point metal and stirring at the liquefaction temperature of the metal for 2-48 hours at a stirring speed of 200 rpm to 600 rpm. The term "nanoscale mixing" as used herein refers to mixing the different raw material particles to a nanometer level.

[0016] In some embodiments, the sintering temperature is 400-600°C.

[0017] In some embodiments, the temperature is adjusted to 400-600° C. at a heating rate of 2-10° C. / min to perform the sintering process.

[0018] In some embodiments, the sintering treatment time is 2-48 hours.

[0019] In some embodiments, the raw materials include alkali metal sulfide, lithium halide, and phosphorus-sulfur compound. The content of alkali metal sulfide, lithium halide, and phosphorus-sulfur compound in the raw materials can be weighed according to the molar ratio of each element in the chemical formula of the sulfide solid electrolyte (i.e., the preset molar ratio), which is not particularly limited in the present invention. The alkali metal sulfide can be, for example, Li2S, the lithium halide can be, for example, LiCl, and the phosphorus-sulfur compound can be, for example, P2S5, but are not limited thereto.

[0020] A second object of the present invention is to provide a method for preparing a sulfide solid electrolyte, comprising:

[0021] A sulfide solid electrolyte preparation device is provided, wherein the preparation device includes a reaction mechanism, and the reaction mechanism includes a reaction container;

[0022] Adding raw materials and a low-melting-point metal into the reaction vessel, adjusting the temperature in the reaction vessel to a metal liquefaction temperature to liquefy the low-melting-point metal to form liquid metal, and performing nanoscale mixing; wherein the raw materials contain elements required for synthesizing a sulfide solid electrolyte in a predetermined molar ratio, and the melting point of the low-melting-point metal is below 100° C.;

[0023] The temperature of the reaction container is then adjusted to a sintering temperature to perform a reaction and generate a sulfide solid electrolyte.

[0024] In some embodiments, the low melting point metal includes at least one of mercury, cesium, and rubidium.

[0025] In some embodiments, the content of the liquid metal in the mixture is 60 wt % to 80 wt %.

[0026] In some embodiments, the raw materials include alkali metal sulfide, lithium halide, and a phosphorus-sulfur compound. The content of the alkali metal sulfide, lithium halide, and phosphorus-sulfur compound in the raw materials can be weighed according to the molar ratio of each element in the chemical formula of the sulfide solid electrolyte (i.e., the predetermined molar ratio), which is not particularly limited in the present invention.

[0027] In some embodiments, the metal liquefaction temperature is 20-300°C.

[0028] In some embodiments, the temperature in the reaction container is raised to the metal liquefaction temperature at a heating rate of 2-10° C. / min.

[0029] In some embodiments, the nanoscale mixing includes stirring the raw material and the liquid metal at the metal liquefaction temperature for 2-48 hours at a stirring speed of 200 rpm to 600 rpm.

[0030] In some embodiments, the sintering temperature is 400-600°C.

[0031] In some embodiments, the temperature is increased from the metal liquidus temperature to the sintering temperature at a heating rate of 2-10° C. / min.

[0032] In some embodiments, the reaction is carried out by maintaining the sintering temperature for 2-48 hours.

[0033] In some embodiments, the reaction vessel is a heated stirred tank.

[0034] In some embodiments, the preparation device further includes a condensation mechanism connected to the reaction container;

[0035] The preparation method further includes: after the reaction is completed, adjusting the temperature within the reaction vessel to a metal vaporization temperature to vaporize the low-melting-point metal in the reaction product, and allowing the vaporized low-melting-point metal to enter the condensation mechanism for cooling and recovery. The "metal vaporization temperature" in the present invention refers to a temperature at which the low-melting-point metal can vaporize and maintain a gaseous state.

[0036] In some embodiments, the metal vaporization temperature is 500-900°C.

[0037] In some embodiments, the temperature is increased from the sintering temperature to the metal vaporization temperature at a heating rate of 2-10° C. / min.

[0038] In some embodiments, the method further comprises: after the reaction is completed, cooling the reaction vessel to room temperature at a cooling rate of 2-10°C / min, and collecting the produced sulfide solid electrolyte. For example, after vaporizing the low-melting-point metal, the temperature is cooled from the metal vaporization temperature to room temperature at a cooling rate of 2-10°C / min.

[0039] A third object of the present invention is to provide a sulfide solid electrolyte prepared by any of the methods described above.

[0040] In some embodiments, the chemical formula of the sulfide solid electrolyte is Li 6-x PS 1+x Cl 1+X , where X = 0 ~ 0.7.

[0041] In some embodiments, the purity of the sulfide solid electrolyte is greater than 99.9%.

[0042] A fourth object of the present invention is to provide a solid-state battery comprising a positive electrode, a negative electrode and a solid electrolyte, wherein the solid electrolyte is the sulfide solid electrolyte.

[0043] Compared with existing technologies, the present invention has at least the following advantages: It provides a liquid-phase method for preparing sulfide solid electrolytes without the use of organic solvents. The resulting product is high-purity and free of carbon residue, resolving the problem of solvent mixing methods in the prior art, which introduces carbon residues and leads to performance degradation of sulfide solid electrolytes. Furthermore, the preparation method provided by the present invention is simple and can be implemented continuously, requiring minimal equipment, making it suitable for industrialization and industrialization, resolving the difficulty of scalability of the prior art solid-phase ball milling method. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0045] Figure 1 1 is a process flow chart of Example 1 of the present invention.

[0046] Figure 2 This is an XRD characterization diagram of the high-purity LPSC solid electrolyte prepared in Example 1 of the present invention.

[0047] Figure 3 This is an XRD characterization diagram of the high-purity LPSC solid electrolyte prepared in Example 2 of the present invention.

[0048] Figure 4 This is an XRD characterization diagram of the high-purity LPSC solid electrolyte prepared in Example 3 of the present invention. DETAILED DESCRIPTION

[0049] The technical solutions of the present invention are described in detail below in conjunction with specific embodiments so that those skilled in the art can better understand and implement the technical solutions of the present invention. The specific functional details disclosed herein should not be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching those skilled in the art to employ the present invention in various ways in virtually any appropriate detailed embodiment.

[0050] In addition, unless otherwise specified, the various raw materials used in the following examples can be purchased from the market, etc., the various production and testing equipment used are also equipment known in the art, and the testing methods used are also methods known in the art.

[0051] Example 1

[0052] This embodiment provides a novel liquid phase method for preparing sulfide solid electrolytes. Figure 1 It is the process flow chart of this embodiment. Figure 1 As shown, the preparation device for implementing the preparation method includes a reaction mechanism and a condensation mechanism. The reaction mechanism includes a stirring kettle. The condensation mechanism includes a condensation tower, a refrigerator and a low-melting-point metal recovery tank. The refrigerator is used to cool the condensation tower, and the condensation tower is connected to the stirring kettle and the low-melting-point metal recovery tank.

[0053] The preparation method of this embodiment specifically includes the following steps:

[0054] Step 1: Add the raw materials Li2S, LiCl and P2S5 in a molar ratio of 5:2:1 into a stirred tank, and then add mercury metal accounting for 60% of the total mass ratio;

[0055] Step 2: Raise the temperature of the stirred tank to 200°C at a heating rate of 3°C / min to liquefy the mercury metal, and stir and mix at 200°C for 10 hours at a rotation speed of 400 rpm to achieve nanoscale mixing of Li2S, LiCl, P2S5, and liquid metal mercury to obtain a mixed material;

[0056] Step 3: While maintaining continuous stirring and a rotation speed of 300 rpm, the temperature was raised to 500° C. at a heating rate of 3° C. / min for 9 hours to carry out the reaction, thereby obtaining a high-purity sulfide solid electrolyte;

[0057] Step 4: Open the low-melting-point metal outlet valve at the top of the stirred kettle and raise the temperature to 600°C at a heating rate of 3°C / min to vaporize the mercury. The gaseous mercury metal enters the condensation tower through the outlet valve at the top of the stirred kettle to be condensed. The condensed metallic mercury enters the low-melting-point metal recovery tank for recovery;

[0058] Step 5: Cool the stirred tank to room temperature at a cooling rate of 3°C / min to collect the high-purity LPSC solid electrolyte;

[0059] Step 6: After preparation, remove and clean the mold and return it to its original state.

[0060] Figure 2 This is an XRD characterization diagram of the high-purity LPSC solid electrolyte prepared in this example.

[0061] Example 2

[0062] This embodiment provides a novel liquid phase method for preparing a sulfide solid electrolyte. The preparation apparatus used is the same as that in Example 1, and specifically includes the following steps:

[0063] Step 1: Add the raw materials Li2S, LiCl and P2S5 in a molar ratio of 4:3:1 into a stirred tank, and then add mercury metal accounting for 70% of the total mass ratio;

[0064] Step 2: Raise the temperature of the stirred tank to 250°C at a heating rate of 5°C / min to liquefy the mercury metal, and stir and mix at 250°C for 20 hours at a rotation speed of 300 rpm to achieve nanoscale mixing of Li2S, LiCl, P2S5 and liquid metal mercury to obtain a mixed material;

[0065] Step 3: While maintaining continuous stirring, raise the temperature to 550° C. at a heating rate of 5° C. / min and heat for 8 hours to react and obtain a high-purity sulfide solid electrolyte;

[0066] Step 4: Open the low-melting-point metal outlet valve at the top of the heated stirred kettle and raise the temperature to 600°C at a heating rate of 5°C / min to vaporize the mercury. The gaseous mercury metal enters the condensation tower through the outlet valve at the top of the stirred kettle to be condensed. The condensed metallic mercury enters the low-melting-point metal recovery tank for recovery;

[0067] Step 5: Cool the stirred tank to room temperature at a cooling rate of 5°C / min to collect the high-purity LPSC solid electrolyte;

[0068] Step 6: After preparation, remove and clean the mold and return it to its original state.

[0069] Figure 3 This is an XRD characterization diagram of the high-purity LPSC solid electrolyte prepared in this example.

[0070] Example 3

[0071] This embodiment provides a novel liquid phase method for preparing a sulfide solid electrolyte. The preparation apparatus used is the same as that in Example 1, and specifically includes the following steps:

[0072] Step 1: Add the raw materials Li2S, LiCl and P2S5 in a molar ratio of 4:3:1 into a stirred tank, and then add mercury metal accounting for 80% of the total mass ratio;

[0073] Step 2: Raise the temperature of the stirred tank to 150°C at a heating rate of 4°C / min to liquefy the mercury metal, and stir and mix at high temperature for 10 hours at a rotation speed of 350 rpm to achieve nanoscale mixing of Li2S, LiCl, P2S5, and liquid metal mercury to obtain a mixed material;

[0074] Step 3: While maintaining continuous stirring, the temperature was raised to 550°C at a heating rate of 4°C / min for 7 hours to carry out the reaction and obtain a high-purity sulfide solid electrolyte;

[0075] Step 4: Open the low-melting-point metal outlet valve at the top of the heated stirred kettle and raise the temperature to 650°C at a heating rate of 4°C / min to vaporize the mercury. The gaseous mercury metal enters the condensation tower through the outlet valve at the top of the stirred kettle to be condensed. The condensed metallic mercury enters the low-melting-point metal recovery tank for recovery;

[0076] Step 5: Cool the stirred tank to room temperature at a cooling rate of 4°C / min and collect the high-purity LPSC solid electrolyte;

[0077] Step 6: After preparation, remove and clean the mold and return it to its original state.

[0078] Figure 4This is an XRD characterization diagram of the high-purity LPSC solid electrolyte prepared in this example.

[0079] Example 4

[0080] This embodiment provides a novel liquid phase method for preparing a sulfide solid electrolyte. The preparation apparatus used is the same as that in Example 1, and specifically includes the following steps:

[0081] This embodiment provides a novel liquid phase method for preparing a sulfide solid electrolyte. The preparation apparatus used is the same as that in Example 1, and specifically includes the following steps:

[0082] Step 1: Li2S, LiCl and P2S5 are added into a stirred tank at a molar ratio of 4:3:1, followed by the addition of 70 wt% cesium metal;

[0083] Step 2: Raise the temperature of the stirred tank to 30°C at a heating rate of 2°C / min to liquefy the cesium metal, and stir and mix at a speed of 200 rpm under this high temperature condition for 48 hours to achieve nanoscale mixing of Li2S, LiCl, P2S5 and liquid metal cesium to obtain a mixed material;

[0084] Step 3: While maintaining continuous stirring, the temperature was raised to 100°C at a heating rate of 2°C / min and heated for 24 hours to react and obtain a high-purity sulfide solid electrolyte;

[0085] Step 4: Open the low-melting-point metal outlet valve at the top of the heated stirred kettle, and raise the temperature to 700°C at a heating rate of 2°C / min to vaporize the cesium. The gaseous cesium metal enters the condensation tower from the outlet valve at the top of the stirred kettle and is condensed. The condensed metallic cesium enters the low-melting-point metal recovery tank for recovery;

[0086] Step 5: Cool the stirred tank to room temperature at a cooling rate of 2°C / min and collect the high-purity LPSC solid electrolyte;

[0087] Step 6: After preparation, remove and clean the mold and return it to its original state.

[0088] Example 5

[0089] This embodiment provides a novel liquid phase method for preparing a sulfide solid electrolyte. The preparation apparatus used is the same as that in Example 1, and specifically includes the following steps:

[0090] This embodiment provides a novel liquid phase method for preparing a sulfide solid electrolyte. The preparation apparatus used is the same as that in Example 1, and specifically includes the following steps:

[0091] Step 1: Add the raw materials Li2S, LiCl and P2S5 in a molar ratio of 5:2:1 into a stirred tank, and then add 60w t% rubidium metal;

[0092] Step 2: Raise the temperature of the stirred tank to 50°C at a heating rate of 10°C / min to liquefy the rubidium metal, and stir and mix at a speed of 600 rpm for 2 hours under this high temperature condition to achieve nanoscale mixing of Li2S, LiCl, P2S5 and liquid metal rubidium to obtain a mixed material;

[0093] Step 3: While maintaining continuous stirring, the temperature was raised to 160°C at a heating rate of 10°C / min and heated for 36 hours to react and obtain a high-purity sulfide solid electrolyte;

[0094] Step 4: Open the low-melting-point metal outlet valve at the top of the heated stirred tank, and raise the temperature to 700°C at a heating rate of 10°C / min to vaporize the rubidium. The gaseous rubidium metal enters the condensation tower from the outlet valve at the top of the stirred tank and is condensed. The condensed metallic rubidium enters the low-melting-point metal recovery tank for recovery;

[0095] Step 5: Cool the stirred tank to room temperature at a cooling rate of 10°C / min and collect the high-purity LPSC solid electrolyte;

[0096] Step 6: After preparation, remove and clean the mold and return it to its original state.

[0097] Comparative Example 1

[0098] Comparative Example 1: A sulfide solid electrolyte was prepared by a solid-phase ball milling method in the prior art, specifically comprising:

[0099] The raw materials Li2S, LiCl and P2S5 were mixed in a ratio of 5:2:1 using a high-energy ball mill for 10 hours to obtain a mixture; the mixture was disassembled in a glove box, and the mixture obtained by ball milling was placed in a muffle furnace and calcined at 550°C for 5 hours to obtain a sulfide solid electrolyte.

[0100] Comparative Example 2

[0101] Comparative Example 2 uses the solvent mixing method in the prior art to prepare a sulfide solid electrolyte, specifically comprising: charging the raw materials Li2S, LiCl and P2S5 into a sealed, heatable stirring tank at a ratio of 5:2:1, adding an organic solvent such as ethanol, heating and stirring for 48 hours, and then evaporating the organic solvent to obtain a powder, placing the powder in a muffle furnace and calcining at a high temperature of 550°C for 5 hours to obtain a sulfide solid electrolyte.

[0102] The present invention also uses elemental analysis to test the purity and carbon residue of the sulfide solid electrolytes prepared in the above examples and comparative examples. The test results are shown in Table 1:

[0103] Table 1

[0104]

[0105] The present invention also uses the sulfide solid electrolyte prepared in the above embodiment to assemble a lithium ion battery, and the obtained lithium ion battery has good electrochemical performance.

[0106] The various aspects, embodiments, features and examples of the present invention should be considered as illustrative in all respects and are not intended to limit the present invention, the scope of which is defined solely by the claims. Other embodiments, modifications and uses will be apparent to those skilled in the art without departing from the spirit and scope of the invention as claimed.

[0107] In addition, the inventors of this case also referred to the aforementioned embodiments and conducted experiments using other raw materials, process operations, and process conditions described in this specification, and obtained relatively ideal results.

[0108] Although the present invention has been described with reference to illustrative embodiments, it will be understood by those skilled in the art that various other changes, omissions, and / or additions may be made and that substantial equivalents may be substituted for the elements of the embodiments without departing from the spirit and scope of the present invention. Additionally, many modifications may be made to adapt specific circumstances or materials to the teachings of the present invention without departing from the scope of the present invention. Therefore, it is not intended herein to limit the present invention to the disclosed specific embodiments for carrying out the present invention, but rather to include all embodiments within the scope of the appended claims. Furthermore, unless specifically stated, any use of the terms first, second, etc. does not indicate any order or importance, but rather uses the terms first, second, etc. to distinguish one element from another.

Claims

1. A method for preparing a sulfide solid electrolyte, characterized in that: include: Providing a raw material containing a predetermined molar ratio of required elements for synthesizing a sulfide solid electrolyte; Mixing the raw material with liquid metal at the nanoscale to obtain a mixed material; The mixed material is sintered to react and generate a sulfide solid electrolyte.

2. The preparation method according to claim 1, characterized in that Specifically include: After mixing the raw material with a low-melting-point metal, the temperature is adjusted to a metal liquefaction temperature to liquefy the low-melting-point metal to form the liquid metal, and the nanoscale mixing is performed under the metal liquefaction temperature to obtain the mixed material, wherein the melting point of the low-melting-point metal is below 100° C.; And / or, the liquid metal includes at least one of liquid mercury, cesium, and rubidium; And / or, the content of the liquid metal in the mixed material is 60wt% to 80wt%; And / or, the nano-scale mixing includes: mixing the raw material with the low melting point metal and stirring the mixture for 2-48 hours at the liquefaction temperature of the metal at a stirring speed of 200 rpm to 600 rpm.

3. The preparation method according to claim 2, wherein: The metal liquefaction temperature is 20-300°C; and / or, heating to the metal liquefaction temperature at a heating rate of 2-10° C. / min.

4. The preparation method according to claim 1, wherein: The sintering temperature is 400-600°C; and / or, adjusting the temperature to 400-600° C. at a heating rate of 2-10° C. / min to perform the sintering treatment; And / or, the sintering treatment time is 2-48h; And / or, the raw materials include alkali metal sulfide, lithium halide and phosphorus sulfur compound.

5. A method for preparing a sulfide solid electrolyte, characterized in that: include: A sulfide solid electrolyte preparation device is provided, wherein the preparation device includes a reaction mechanism, and the reaction mechanism includes a reaction container; Adding raw materials and a low-melting-point metal into the reaction vessel, adjusting the temperature in the reaction vessel to a metal liquefaction temperature to liquefy the low-melting-point metal to form liquid metal, and performing nanoscale mixing; wherein the raw materials contain elements required for synthesizing a sulfide solid electrolyte in a predetermined molar ratio, and the melting point of the low-melting-point metal is below 100° C.; The temperature of the reaction container is then adjusted to a sintering temperature to perform a reaction and generate a sulfide solid electrolyte.

6. The preparation method according to claim 5, characterized in that: The low melting point metal includes at least one of mercury, cesium, and rubidium; And / or, the content of the liquid metal in the mixture is 60wt% to 80wt%. w t%; and / or, the raw materials include alkali metal sulfide, lithium halide and phosphorus-sulfur compound; And / or, the reaction vessel is a heated stirring kettle.

7. The preparation method according to claim 5, characterized in that: The metal liquefaction temperature is 20-300°C; and / or, raising the temperature in the reaction vessel to the metal liquefaction temperature at a heating rate of 2-10° C. / min; And / or, the nano-scale mixing comprises: stirring the raw material and liquid metal at the metal liquefaction temperature for 2-48 hours at a stirring speed of 200 rpm to 600 rpm; and / or, the sintering temperature is 400-600° C.; and / or, raising the temperature from the metal liquefaction temperature to the sintering temperature at a heating rate of 2-10° C. / min; and / or, maintaining the sintering temperature for 2-48 hours to carry out the reaction.

8. The preparation method according to claim 5, characterized in that: The preparation device further includes a condensing mechanism connected to the reaction vessel. The preparation method further includes: after the reaction is completed, adjusting the temperature in the reaction vessel to a metal vaporization temperature to vaporize the low-melting-point metal in the reaction product, and allowing the vaporized low-melting-point metal to enter the condensing mechanism for cooling and recovery; Preferably, the metal vaporization temperature is 500-900°C; Preferably, the temperature is raised from the sintering temperature to the metal gasification temperature at a heating rate of 2-10° C. / min.

9. A sulfide solid electrolyte, characterized in that: It is prepared by the method according to any one of claims 1 to 8; Preferably, the chemical formula of the sulfide solid electrolyte is Li 6-x PS 1+x Cl 1+X， Where X = 0 to 0.7; Preferably, the purity of the sulfide solid electrolyte is above 99.9%.

10. A solid-state battery comprising a positive electrode, a negative electrode, and a solid electrolyte, characterized in that: The solid electrolyte is the sulfide solid electrolyte according to claim 9.

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