Negative electrode for sulfide all-solid-state lithium metal battery, preparation method and battery

Abstract

The invention provides a negative electrode for a sulfide all-solid-state lithium metal battery, a preparation method and a battery, and the preparation method comprises the following steps: uniformly mixing nitrile rubber, a lithium salt and a non-aqueous solvent according to a ratio to obtain protective layer slurry; coating lithium metal with the protective layer slurry, and heating to volatilize part of the non-aqueous solvent to obtain a coated pole piece; and cross-linking and aging the nitrile rubber in the coated pole piece in an ultraviolet environment to obtain the negative pole piece. According to the invention, the non-aqueous solvent and the lithium salt form a stable complex, a high-concentration lithium salt complex system is constructed, CN <-> in the nitrile rubber can be coordinated with Li < + > in the high-concentration lithium salt complex, a continuous Li < + > transmission channel is constructed, and the nitrile rubber is compact and hard after cross-linking and aging; therefore, the lithium metal can be prevented from being in direct contact with the sulfide solid electrolyte and active oxygen separated from the positive electrode, and the negative electrode plate has good ion conduction performance, so that the sulfide all-solid-state lithium metal battery has good safety and electrochemical performance.

Description

Technical Field

[0001] This invention relates to the field of lithium metal battery technology, and in particular to a negative electrode, preparation method and battery for a sulfide all-solid-state lithium metal battery. Background Technology

[0002] All-solid-state lithium metal batteries offer advantages such as no leakage risk and excellent safety due to the use of solid electrolytes instead of traditional liquid electrolytes. Especially when paired with high-nickel ternary cathodes, they achieve extremely high energy density, making them a core development direction for next-generation energy storage devices. Among these, sulfide solid electrolytes are widely used in all-solid-state lithium metal battery systems due to their high ionic conductivity and good machinability.

[0003] However, existing sulfide-based all-solid-state lithium metal batteries still face two major technical bottlenecks. First, when the electrolyte is in direct contact with the lithium metal anode, it is easily electrochemically reduced by nucleophilic lithium metal, generating a mixed ion and electron conduction interface that leads to continuous decomposition of the sulfide. Simultaneously, the sulfide particles contain numerous pores and cracks on their surface and inside, causing Li... + Uneven deposition on the surface of lithium metal anode allows lithium dendrites to grow in these pores and cracks, ultimately leading to battery failure. Secondly, high-nickel ternary cathode materials easily release active oxygen at high temperatures. This active oxygen rapidly diffuses to the anode, reacts with reduced lithium metal, triggers violent exothermic reactions, and accelerates battery thermal runaway. Summary of the Invention

[0004] The purpose of this invention is to provide a negative electrode, a preparation method, and a battery for sulfide all-solid-state lithium metal batteries, in order to solve the problems in the prior art.

[0005] The technical solution adopted in this invention includes: a method for preparing a negative electrode for a sulfide all-solid-state lithium metal battery, comprising the following steps:

[0006] Nitrile rubber, lithium salt and non-aqueous solvent are mixed in a certain proportion to obtain a protective layer slurry;

[0007] A protective layer slurry is coated onto lithium metal and heated to evaporate some of the non-aqueous solvent, resulting in a coated electrode.

[0008] The negative electrode is obtained by cross-linking and aging the nitrile rubber in the coated electrode using an ultraviolet environment.

[0009] Preferably, the molar ratio of nitrile rubber to lithium salt is (0.5~5):1.

[0010] Preferably, the concentration of lithium salt in the protective layer slurry is 1~3 mol / L.

[0011] Preferably, the lithium salt includes at least one of lithium hexafluorophosphate, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium tetrafluoroborate, lithium dioxalate borate, lithium difluorooxalate borate, lithium difluorophosphate, lithium perchlorate, and lithium chloride.

[0012] Preferably, the non-aqueous solvent includes at least one of acetonitrile, propionitrile, N,N-dimethylformamide, N,N-dimethylacetamide, chloroform, carbon tetrachloride, 1,2-dichloroethane, cyclohexanone, γ-butyrolactone, tetrahydrofuran, dioxane, butyl acetate, hexyl butyrate, dibutyl phthalate, toluene, and xylene.

[0013] Preferred conditions for heating to cause partial evaporation of non-aqueous solvents: heating temperature of 40~80℃ and heating time of 2~48h.

[0014] Preferably, the conditions for crosslinking and aging the nitrile rubber in the coated electrode using ultraviolet light are: ultraviolet light irradiation power of 0.5~1.5W / m2 and ultraviolet light irradiation time of 10~150min.

[0015] Preferably, the step of mixing nitrile rubber, lithium salt, and non-aqueous solvent in a specified ratio includes:

[0016] (1) Using molecular sieves to remove water from non-aqueous solvents;

[0017] (2) Use nitrile rubber and lithium salt in the specified proportions;

[0018] (3) Mix the substances obtained in steps (1) and (2) in the correct proportions.

[0019] The technical solution of the present invention also includes: a negative electrode for a sulfide all-solid-state lithium metal battery, wherein the negative electrode for the sulfide all-solid-state lithium metal battery is prepared by the above method.

[0020] The technical solution of the present invention also includes: a sulfide all-solid-state lithium metal battery, wherein the above-mentioned negative electrode is disposed in the sulfide all-solid-state lithium metal battery.

[0021] The beneficial effects of this invention are as follows: The negative electrode sheet prepared by the method provided by this invention includes lithium metal and a negative electrode protective layer coated on the lithium metal. The negative electrode protective layer contains cross-linked aged nitrile rubber, lithium salt, and a portion of non-aqueous solvent. The non-aqueous solvent can form a stable complex with the lithium salt, thereby constructing a high-concentration lithium salt complex system. The CN content in the nitrile rubber... - Li can form complexes with high concentrations of lithium salts. + Coordination occurs, constructing continuous Li + Transmission channel, reducing Li +The migration barrier of nitrile rubber is dense and hard after cross-linking and aging. Therefore, the negative electrode protective layer can effectively isolate lithium metal from the sulfide solid electrolyte and the active oxygen released from the positive electrode. At the same time, it has good ion conduction performance, which makes the sulfide all-solid-state lithium metal battery have good safety and electrochemical performance. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] This invention provides a method for preparing a negative electrode for a sulfide-based all-solid-state lithium metal battery, comprising the following steps:

[0024] S1. Mix nitrile rubber, lithium salt and non-aqueous solvent in a certain proportion to obtain protective layer slurry;

[0025] S2. Coat the protective layer slurry onto lithium metal and heat it to evaporate some of the non-aqueous solvents to obtain a coated electrode.

[0026] S3. Use ultraviolet light to crosslink and age the nitrile rubber in the coated electrode to obtain the negative electrode.

[0027] The negative electrode sheet prepared by the above method includes lithium metal and a negative electrode protective layer coated on the lithium metal. The negative electrode protective layer contains cross-linked aged nitrile rubber, lithium salt, and some non-aqueous solvent. The non-aqueous solvent can form a stable complex with the lithium salt, thereby constructing a high-concentration lithium salt complex system. The CN content in the nitrile rubber... - Li can form complexes with high concentrations of lithium salts. + Coordination occurs, constructing continuous Li + Transmission channel, reducing Li + The migration barrier of nitrile rubber is dense and hard after cross-linking and aging. Therefore, the negative electrode protective layer can effectively isolate lithium metal from the sulfide solid electrolyte and the active oxygen released from the positive electrode, while also having good ion conduction performance.

[0028] The above step S1 specifically includes:

[0029] (1) Using molecular sieves to remove water from non-aqueous solvents: During operation, add molecular sieves to the non-aqueous solvent, store it in a glove box, and then filter to remove the molecular sieves.

[0030] Preferably, the molecular sieve has a radius of 3~5mm, a type of 4Å, a static water adsorption capacity (25℃, saturated saline, 24h) ≥22.5%, a static water adsorption capacity (35℃, saturated saline, 24h) ≥22%, a crushing resistance ≥80N, a particle size (gravimetric method) ≥98%, and a spherical shape.

[0031] Preferably, the settling conditions for the non-aqueous solvent and molecular sieve mixture in the glove box are: argon gas filling, O2 < 0.5 ppm, H2O < 0.5 ppm, and settling time of 48 h.

[0032] Optionally, the non-aqueous solvent includes at least one of acetonitrile, propionitrile, N,N-dimethylformamide, N,N-dimethylacetamide, chloroform, carbon tetrachloride, 1,2-dichloroethane, cyclohexanone, γ-butyrolactone, tetrahydrofuran, dioxane, butyl acetate, hexyl butyrate, dibutyl phthalate, toluene, and xylene.

[0033] (2) Take nitrile rubber and lithium salt in the following proportion: During operation, put nitrile rubber and lithium salt into a container with a magnetic stir bar in a molar ratio of (0.5~5):1. The magnetic stir bar is a polytetrafluoroethylene magnetic stir bar and the container is a silicate transparent glass bottle.

[0034] Optionally, the lithium salt includes at least one of lithium hexafluorophosphate, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium tetrafluoroborate, lithium dioxalate borate, lithium difluorooxalate borate, lithium difluorophosphate, lithium perchlorate, and lithium chloride.

[0035] (3) Mix the substances obtained in steps (1) and (2) in proportion: During operation, according to the concentration of lithium salt in the protective layer slurry being 1~3 mol / L, add the dehydrated non-aqueous solvent to the container in step (2), start magnetic stirring, and stir the resulting mixture evenly to form a clear and transparent gel-like liquid, which is the protective layer slurry.

[0036] The above-mentioned step S2 specifically includes: during operation, a protective layer slurry is coated onto the surface of lithium metal to form a uniform transparent liquid layer on the surface of lithium metal; the transparent liquid layer is heated for a period of time to allow the non-aqueous solvent portion to evaporate, thereby obtaining a coating containing a portion of the non-aqueous solvent, thus obtaining a coated electrode containing the coating and lithium metal.

[0037] Preferred conditions for heating to cause partial evaporation of non-aqueous solvents: heating temperature of 40~80℃ and heating time of 2~48h.

[0038] The above-mentioned step S3 specifically includes: during operation, the coated electrode is placed under ultraviolet light for a period of time to allow the nitrile rubber in the coating to crosslink and age, thus obtaining the negative electrode.

[0039] Preferably, the conditions for crosslinking and aging the nitrile rubber in the coated electrode using ultraviolet light are: ultraviolet light irradiation power of 0.5~1.5W / m 2 The ultraviolet light irradiation time is 10~150min.

[0040] This invention also provides a negative electrode for a sulfide-based all-solid-state lithium metal battery prepared by the above method, and a sulfide-based all-solid-state lithium metal battery assembled using this negative electrode. This sulfide-based all-solid-state lithium metal battery exhibits good safety and electrochemical performance: the cross-linked and aged nitrile rubber has good mechanical strength, is uniform and dense, and can effectively prevent side reactions between lithium metal and the sulfide solid electrolyte and the active oxygen released from the positive electrode, ensuring good cycle life and thermal safety of the battery. Furthermore, the continuous Li-type lithium metal battery composed of nitrile rubber, non-aqueous solvent, and lithium salt... + The transmission channel ensures that the battery has good rate performance.

[0041] The following are specific embodiments and comparative examples of the present invention, wherein: experimental methods not specifically described in terms of operation steps are performed in accordance with the corresponding product instructions; instruments, reagents, and consumables used, unless otherwise specified, can be purchased from commercial companies. There are no particular restrictions on the source of any raw materials used in the present invention; they can be purchased from the market and prepared using conventional methods well known to those skilled in the art. There are no particular restrictions on the purity of any raw materials used in the present invention; however, analytical grade or conventional purity in the lithium battery field is preferred.

[0042] Example 1

[0043] S1. Preparation of protective layer slurry:

[0044] (1) Add molecular sieve to 500 mL of hexyl butyrate (non-aqueous solvent), let stand in a glove box for 48 h, and then filter to remove the molecular sieve;

[0045] (2) Place 0.5 mol of nitrile rubber and 0.5 mol of LiFSI (lithium salt) into a silicate transparent glass bottle containing a polytetrafluoroethylene magnetic stir bar;

[0046] (3) Add the dehydrated hexyl butyrate from step (1) to the silicate transparent glass bottle from step (2), start magnetic stirring, and stir the resulting mixture evenly to form a clear and transparent gel-like liquid, which is the protective layer slurry.

[0047] S2. Preparation of coated electrode sheets:

[0048] A protective slurry is coated onto the lithium metal surface, forming a uniform transparent liquid layer on the lithium metal surface.

[0049] The transparent liquid layer is heated at 60°C for 24 hours to partially evaporate the hexyl butyrate, resulting in a coating containing a portion of hexyl butyrate (appearing as a viscous and transparent layer), thus obtaining a coated electrode containing the coating and lithium metal.

[0050] S3. Preparation of the negative electrode sheet:

[0051] The coated electrode was placed under ultraviolet light at a rate of 0.8 W / m. 2 Irradiate with high power for 30 minutes to cause the nitrile rubber in the coating to crosslink and age, thus obtaining the negative electrode sheet.

[0052] Example 2

[0053] S1. Preparation of protective layer slurry:

[0054] (1) Add molecular sieve to 500 mL of hexyl butyrate (non-aqueous solvent), let stand in a glove box for 48 h, and then filter to remove the molecular sieve;

[0055] (2) Place 1 mol of nitrile rubber and 0.5 mol of LiFSI (lithium salt) into a silicate transparent glass bottle containing a polytetrafluoroethylene magnetic stir bar;

[0056] (3) Add the dehydrated hexyl butyrate from step (1) to the silicate transparent glass bottle from step (2), start magnetic stirring, and stir the resulting mixture evenly to form a clear and transparent gel-like liquid, which is the protective layer slurry.

[0057] S2. Preparation of coated electrode sheets:

[0058] A protective slurry is coated onto the lithium metal surface, forming a uniform transparent liquid layer on the lithium metal surface.

[0059] The transparent liquid layer is heated at 60°C for 24 hours to partially evaporate the hexyl butyrate, resulting in a coating containing a portion of hexyl butyrate (appearing as a viscous and transparent layer), thus obtaining a coated electrode containing the coating and lithium metal.

[0060] S3. Preparation of the negative electrode sheet:

[0061] The coated electrode was placed under ultraviolet light at a rate of 0.8 W / m. 2 Irradiate with high power for 30 minutes to cause the nitrile rubber in the coating to crosslink and age, thus obtaining the negative electrode sheet.

[0062] Example 3

[0063] S1. Preparation of protective layer slurry:

[0064] (1) Add molecular sieve to 500 mL of hexyl butyrate (non-aqueous solvent), let stand in a glove box for 48 h, and then filter to remove the molecular sieve;

[0065] (2) Place 1 mol of nitrile rubber and 0.5 mol of LiFSI (lithium salt) into a silicate transparent glass bottle containing a polytetrafluoroethylene magnetic stir bar;

[0066] (3) Add the dehydrated hexyl butyrate from step (1) to the silicate transparent glass bottle from step (2), start magnetic stirring, and stir the resulting mixture evenly to form a clear and transparent gel-like liquid, which is the protective layer slurry.

[0067] S2. Preparation of coated electrode sheets:

[0068] A protective slurry is coated onto the lithium metal surface, forming a uniform transparent liquid layer on the lithium metal surface.

[0069] The transparent liquid layer is heated at 60°C for 24 hours to partially evaporate the hexyl butyrate, resulting in a coating containing a portion of hexyl butyrate (appearing as a viscous and transparent layer), thus obtaining a coated electrode containing the coating and lithium metal.

[0070] S3. Preparation of the negative electrode sheet:

[0071] The coated electrode was placed under ultraviolet light at 1 W / m 2 Irradiate with high power for 30 minutes to cause the nitrile rubber in the coating to crosslink and age, thus obtaining the negative electrode sheet.

[0072] Example 4

[0073] S1. Preparation of protective layer slurry:

[0074] (1) Add molecular sieve to 500 mL of hexyl butyrate (non-aqueous solvent), let stand in a glove box for 48 h, and then filter to remove the molecular sieve;

[0075] (2) Place 1 mol of nitrile rubber and 0.5 mol of LiFSI (lithium salt) into a silicate transparent glass bottle containing a polytetrafluoroethylene magnetic stir bar;

[0076] (3) Add the dehydrated hexyl butyrate from step (1) to the silicate transparent glass bottle from step (2), start magnetic stirring, and stir the resulting mixture evenly to form a clear and transparent gel-like liquid, which is the protective layer slurry.

[0077] S2. Preparation of coated electrode sheets:

[0078] A protective slurry is coated onto the lithium metal surface, forming a uniform transparent liquid layer on the lithium metal surface.

[0079] The transparent liquid layer is heated at 60°C for 24 hours to partially evaporate the hexyl butyrate, resulting in a coating containing a portion of hexyl butyrate (appearing as a viscous and transparent layer), thus obtaining a coated electrode containing the coating and lithium metal.

[0080] S3. Preparation of the negative electrode sheet:

[0081] The coated electrode was placed under ultraviolet light at a rate of 0.8 W / m. 2 Irradiate with high power for 60 minutes to cause the nitrile rubber in the coating to crosslink and age, thus obtaining the negative electrode sheet.

[0082] Example 5

[0083] A high-nickel ternary cathode material coated with commercial lithium niobate was mixed with a sulfide electrolyte Li6PS5Cl, a conductive agent acetylene black, and a binder PTFE in cyclohexane at a mass ratio of 80:17:1:2. The mixture was stirred at high speed at 2500 rpm for 3 hours to obtain an electrolyte composite cathode slurry. The cathode slurry was coated onto aluminum foil and dried to obtain an electrolyte-cathode composite electrode.

[0084] LLZO was dissolved in DMF and stirred thoroughly. The resulting mixture was coated onto a PET base film and dried. The LLZO separator was then transferred onto the electrolyte-positive electrode composite sheet.

[0085] The negative electrode obtained in Example 1 and the electrolyte-positive composite electrode obtained in Example 5 were stacked, packaged, baked, sealed, left to stand, formed, and tested to produce a 20Ah-level sulfide all-solid-state lithium metal battery.

[0086] Example 6

[0087] A high-nickel ternary cathode material coated with commercial lithium niobate was mixed with a sulfide electrolyte Li6PS5Cl, a conductive agent acetylene black, and a binder PTFE in cyclohexane at a mass ratio of 80:17:1:2. The mixture was stirred at high speed at 2500 rpm for 3 hours to obtain an electrolyte composite cathode slurry. The cathode slurry was coated onto aluminum foil and dried to obtain an electrolyte-cathode composite electrode.

[0088] LLZO was dissolved in DMF and stirred thoroughly. The resulting mixture was coated onto a PET base film and dried. The LLZO separator was then transferred onto the electrolyte-positive electrode composite sheet.

[0089] The negative electrode obtained in Example 2 and the electrolyte-positive composite electrode obtained in Example 6 were stacked, packaged, baked, packaged again, left to stand, formed, and tested for capacity to produce a 20Ah-level sulfide all-solid-state lithium metal battery.

[0090] Example 7

[0091] A high-nickel ternary cathode material coated with commercial lithium niobate was mixed with a sulfide electrolyte Li6PS5Cl, a conductive agent acetylene black, and a binder PTFE in cyclohexane at a mass ratio of 80:17:1:2. The mixture was stirred at high speed at 2500 rpm for 3 hours to obtain an electrolyte composite cathode slurry. The cathode slurry was coated onto aluminum foil and dried to obtain an electrolyte-cathode composite electrode.

[0092] LLZO was dissolved in DMF and stirred thoroughly. The resulting mixture was coated onto a PET base film and dried. The LLZO separator was then transferred onto the electrolyte-positive electrode composite sheet.

[0093] The negative electrode obtained in Example 3 and the electrolyte-positive composite electrode obtained in Example 7 were stacked, packaged, baked, sealed, left to stand, formed, and tested to produce a 20Ah-level sulfide all-solid-state lithium metal battery.

[0094] Example 8

[0095] A high-nickel ternary cathode material coated with commercial lithium niobate was mixed with a sulfide electrolyte Li6PS5Cl, a conductive agent acetylene black, and a binder PTFE in cyclohexane at a mass ratio of 80:17:1:2. The mixture was stirred at high speed at 2500 rpm for 3 hours to obtain an electrolyte composite cathode slurry. The cathode slurry was coated onto aluminum foil and dried to obtain an electrolyte-cathode composite electrode.

[0096] LLZO was dissolved in DMF and stirred thoroughly. The resulting mixture was coated onto a PET base film and dried. The LLZO separator was then transferred onto the electrolyte-positive electrode composite sheet.

[0097] The negative electrode obtained in Example 4 and the electrolyte-positive composite electrode obtained in Example 8 were stacked, packaged, baked, packaged again, left to stand, formed, and tested to produce a 20Ah-level sulfide all-solid-state lithium metal battery.

[0098] Comparative Example 1

[0099] A high-nickel ternary cathode material coated with commercial lithium niobate was mixed with a sulfide electrolyte Li6PS5Cl, a conductive agent acetylene black, and a binder PTFE in cyclohexane at a mass ratio of 80:17:1:2. The mixture was stirred at high speed at 2500 rpm for 3 hours to obtain an electrolyte composite cathode slurry. The cathode slurry was coated onto aluminum foil and dried to obtain an electrolyte-cathode composite electrode.

[0100] LLZO was dissolved in DMF and stirred thoroughly. The resulting mixture was coated onto a PET base film and dried. The LLZO separator was then transferred onto the electrolyte-positive electrode composite sheet.

[0101] A 20Ah-level sulfide all-solid-state lithium metal battery was fabricated by stacking, packaging, baking, sealing, settling, forming, and capacity testing of the lithium metal anode and the electrolyte-cathode composite electrode obtained in Comparative Example 1.

[0102] Performance testing:

[0103] The sulfide all-solid-state lithium metal batteries obtained in Examples 5-8 and Comparative Example 1 were tested under the following conditions:

[0104] (1) Specific energy test: 0.2C charge and discharge at 25℃.

[0105] (2) Needle penetration test: When the battery is fully charged (100% SOC), use a steel needle with a diameter of 3 mm and a taper of 30° to radially penetrate the battery at a speed of 40 mm / s. The steel needle stays in the battery for 1 hour.

[0106] (3) 180℃ hot box test: Measure the battery voltage V1 when the battery is fully charged (100% SOC); place the battery in an environment of 180℃±2℃ for 24h, then transfer the battery to an environment of 25℃±2℃ for 4h, then check the battery status and measure the battery voltage V2.

[0107] The above-mentioned needle penetration test passed when the battery did not catch fire, and the hot box test passed when the battery voltage change V1-V2 did not exceed 0.2V. The test results are shown in the table below:

[0108] Battery source Specific energy (Wh / kg) Needle prick test pass rate 180℃ hot box test pass rate Example 5 310 8 / 10 8 / 10 Example 6 310 9 / 10 8 / 10 Example 7 310 8 / 10 9 / 10 Example 8 310 9 / 10 9 / 10 Comparative Example 1 310 4 / 10 6 / 10

[0109] In the table above, n / 10 indicates that n out of 10 battery samples in each batch pass the test. The table shows that the negative electrode prepared using this invention can effectively improve the safety performance of sulfide-based all-solid-state lithium metal batteries and maintain good electrochemical performance.

[0110] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the claims, or equivalent forms of such scope and boundaries.

Claims

1. A method for preparing a negative electrode for a sulfide-based all-solid-state lithium metal battery, characterized in that, Including the following steps: Nitrile rubber, lithium salt and non-aqueous solvent are mixed in a certain proportion to obtain a protective layer slurry; A protective layer slurry is coated onto lithium metal and heated to evaporate some of the non-aqueous solvent, resulting in a coated electrode. The negative electrode is obtained by cross-linking and aging the nitrile rubber in the coated electrode using an ultraviolet environment.

2. The method for preparing the negative electrode for a sulfide-based all-solid-state lithium metal battery according to claim 1, characterized in that, The molar ratio of nitrile rubber to lithium salt is (0.5~5):

1.

3. The method for preparing the negative electrode for a sulfide-based all-solid-state lithium metal battery according to claim 1 or 2, characterized in that, The concentration of lithium salt in the protective layer slurry is 1~3 mol / L.

4. The method for preparing the negative electrode for a sulfide-based all-solid-state lithium metal battery according to claim 3, characterized in that, Lithium salts include at least one of lithium hexafluorophosphate, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium tetrafluoroborate, lithium dioxalate borate, lithium difluorooxalate borate, lithium difluorophosphate, lithium perchlorate, and lithium chloride.

5. The method for preparing the negative electrode for a sulfide-based all-solid-state lithium metal battery according to claim 3, characterized in that, Non-aqueous solvents include at least one of acetonitrile, propionitrile, N,N-dimethylformamide, N,N-dimethylacetamide, chloroform, carbon tetrachloride, 1,2-dichloroethane, cyclohexanone, γ-butyrolactone, tetrahydrofuran, dioxane, butyl acetate, hexyl butyrate, dibutyl phthalate, toluene, and xylene.

6. The method for preparing the negative electrode for a sulfide-based all-solid-state lithium metal battery according to claim 5, characterized in that, Conditions for heating to evaporate some of the non-aqueous solvent: heating temperature 40~80℃, heating time 2~48h.

7. The method for preparing the negative electrode for a sulfide-based all-solid-state lithium metal battery according to any one of claims 1-2 and 4-6, characterized in that, Conditions for crosslinking and aging of nitrile rubber in coated electrodes using ultraviolet light: ultraviolet light irradiation power of 0.5~1.5W / m 2 The ultraviolet light irradiation time is 10~150min.

8. The method for preparing the negative electrode for a sulfide-based all-solid-state lithium metal battery according to claim 7, characterized in that, The steps of mixing nitrile rubber, lithium salt, and non-aqueous solvent in a specific ratio include: (1) Using molecular sieves to remove water from non-aqueous solvents; (2) Use nitrile rubber and lithium salt in the specified proportions; (3) Mix the substances obtained in steps (1) and (2) in the correct proportions.

9. A negative electrode for a sulfide-based all-solid-state lithium metal battery, characterized in that, The negative electrode for the sulfide all-solid-state lithium metal battery is prepared by the method described in any one of claims 1-8.

10. A sulfide-based all-solid-state lithium metal battery, characterized in that, The sulfide all-solid-state lithium metal battery is configured with the negative electrode as described in claim 9.