An artificial interfacial lithium metal protection layer and a preparation method thereof

Abstract

This invention discloses an artificially interfaced lithium metal protective layer and its preparation method. The artificial interface layer comprises a composite material and a binder, and is formed on the surface of a 5μm-15μm substrate using a microgravure coating machine or a casting coating machine. The substrate is PET, Al foil, or Cu foil, and the coating thickness is 1μm-5μm. The material is transferred to the Li metal surface by roll forming. According to the method in this application, after mixing the composite materials, unstable phosphorus material can be encapsulated within stable carbon material to form P-C bonds. This improves the stability of the phosphorus material while reducing the electronic conductivity of the carbon material, which helps the protective layer to adhere stably to the lithium metal surface. When lithium dendrites grow, they alloy with the carbon-coated phosphorus material to form Li. x P acts to suppress lithium dendrite formation.

Description

Technical Field

[0001] This invention relates to the field of lithium battery technology, and in particular to an artificially interfaced lithium metal protective layer and its preparation method. Background Technology

[0002] Replacing traditional fossil fuels with new energy sources to achieve low-carbon and carbon reduction goals has become an inevitable trend. As a key technology for new energy power and energy storage systems, constructing high-energy-density and high-safety lithium battery systems is currently a research focus to support these dual-carbon goals. Currently, the highest energy density of commercially available ternary batteries is only 300Wh / kg, reaching its theoretical limit and failing to meet the demands of technological and social development. Innovation in existing battery materials and the development of new materials are necessary to meet the demand for higher energy-density batteries. Lithium metal anodes have the highest theoretical specific capacity and the lowest electrochemical potential; using lithium metal to replace conventional graphite anodes is an inevitable trend in constructing high-energy-density systems. However, uneven deposition of lithium metal anodes during cycling can generate lithium dendrites, exacerbating instability at the electrolyte interface and potentially inducing internal short circuits, leading to serious safety accidents such as fires and explosions. At high energy densities, these problems are exacerbated, making it difficult to meet daily safety requirements.

[0003] Studies have shown that obtaining an in-situ solid electrolyte interface (SEI) by optimizing the solvent, Li salt, and electrolyte additives can stabilize the uniform deposition / dissolution of lithium to some extent [Zhaoping Liu, ACS Energy Letters, 2021, 6:115]. However, SEIs formed in situ by consuming additives often fail to provide controllable and sufficient mechanical strength to maintain the long-term cycling stability of lithium metal anodes. Compared to in-situ SEIs, designing a non-in-situ artificial interface layer on the lithium metal surface can improve the interfacial stability of lithium metal, thereby avoiding corrosion of highly reactive lithium metal and optimizing lithium metal deposition behavior.

[0004] Constructing a suitable artificial interface layer that effectively reduces the contact between lithium metal and the electrolyte while regulating uniform lithium deposition to suppress side reactions and lithium dendrite growth is crucial for high-performance lithium metal anodes to meet practical applications. This invention discloses a non-in-situ artificial interface layer designed on the lithium metal surface. This layer regulates uniform lithium metal deposition while avoiding reactions between highly reactive lithium metal and the electrolyte, improving the interfacial stability and cycle performance of lithium metal. This design is then applied to lithium metal batteries. Summary of the Invention

[0005] The purpose of this invention is to provide an artificially interfaced lithium metal protective layer and its preparation method, which regulates the uniform deposition of lithium metal while avoiding the reaction between highly active lithium metal and electrolyte, thereby improving the interface stability and cycle performance of lithium metal.

[0006] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0007] A method for preparing an artificially interfaced lithium metal protective layer specifically includes the following steps:

[0008] S1. Under an argon atmosphere, weighed carbon material and agate beads are placed in a ball mill jar in a certain proportion and dispersed evenly by ball milling; then phosphorus material is added to the ball mill jar and dispersed by ball milling to obtain a composite material.

[0009] S2. Add the composite material to the solvent according to the determined solid content, and disperse the material using a double planetary mixer to obtain a uniformly dispersed composite material slurry.

[0010] S3. Add the weighed adhesive to another portion of solvent according to the determined solid content, and disperse it by double planetary stirring to obtain a uniformly dispersed adhesive solution.

[0011] S4. The adhesive solution prepared in step S3 is added to the well dispersed composite material slurry prepared in step S2 and further dispersed by dual planetary stirring to obtain the slurry to be coated.

[0012] S5. Use a micro-gravure coating machine or a casting coating machine to coat the coating slurry prepared in step S4 onto the surface of the substrate, and heat and dry it in the coating machine oven to obtain a sample of a certain thickness to be transferred.

[0013] S6. Use a roller press to continuously transfer the sample to be transferred in step S5 to the surface of lithium metal to obtain lithium metal with an artificial interface layer.

[0014] Preferably, the carbon material in step S1 is one of phosphating graphite, graphene, hard carbon, fluorinated graphite, graphite oxide, and fullerene; the ratio of the carbon material to the agate beads in step S1 is in the range of 1:15-1:25.

[0015] Preferably, the phosphorus material in step S1 is either red phosphorus or black phosphorus; the ratio of carbon material to phosphorus material in step S1 is in the range of 1:2 to 1:5.

[0016] Preferably, the median particle size range of the composite material obtained after ball milling in step S1 is 0.8 μm-4 μm.

[0017] Preferably, in step S2, the solid content of the composite material is 10%-30%, the double planetary stirring speed is 600rpm-1000rpm, and the time is 2h-6h; in step S3, the solid content of the binder is 5%-10%, the double planetary stirring speed is 500rpm-1200rpm, and the time is 4h-6h.

[0018] Preferably, the solvent in steps S2 and S3 is one of dimethylformamide, N-methylpyrrolidone, dimethyl sulfoxide, tetrahydrofuran, and deionized water; the binder in step S3 includes one or more of polyvinylidene fluoride, sodium carboxymethyl cellulose, polyvinylidene fluoride-hexafluoropropylene, polyacrylic acid, polyacrylate, and sodium alginate.

[0019] Preferably, the substrate in step S5 includes one of PET, Al foil, and Cu foil, with a thickness of 5μm-15μm; the thickness of the sample to be transferred in step S5 is 1μm-5μm.

[0020] Preferably, the heating temperature in step S5 is 50℃-80℃.

[0021] Preferably, the composite material accounts for 80%-95% of the total mass of the artificial interface layer, and the adhesive accounts for 5%-20% of the total mass of the artificial interface layer.

[0022] An artificially interfaced lithium metal protective layer includes the artificially interfaced lithium metal protective layer prepared by the above preparation method.

[0023] Compared with the prior art, the advantages of the present invention are as follows:

[0024] 1. According to the method in this application, after mixing the composite materials, unstable phosphorus material can be encapsulated within stable carbon material to form PC bonds. This improves the stability of the phosphorus material while reducing the electronic conductivity of the carbon material, which helps the protective layer to adhere stably to the lithium metal surface. When lithium dendrites grow, they alloy with the carbon-coated phosphorus material to form Li. x P acts to suppress lithium dendrite formation.

[0025] 2. A composite material with PC bonds is formed on the surface of a substrate and then transferred in situ to the lithium metal surface by roll pressing to form an artificial interface layer. Compared with the existing pre-lithiation artificial interface layer, it has small volume change, stable structure, fast Li+ transport and can achieve uniform lithium deposition, which can improve the cycle stability of lithium metal batteries.

[0026] 3. By coating the composite material onto the base material surface, it can be continuously and completely transferred to the Li metal surface through roller pressing, which improves the production efficiency of lithium metal protection. Attached Figure Description

[0027] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 This is a flowchart illustrating the artificial solid-state interface transfer preparation process in an embodiment of the present invention.

[0029] Figure 2 This is a schematic diagram of the charge-discharge cycle performance at a rate of 1C (1C = 180 mA / g relative to NCM811) in an embodiment of the present invention;

[0030] Figure 3 In this embodiment of the invention, 2mA / cm 2 Schematic diagram of the cycle performance of a lithium-lithium symmetric battery at a given rate current density. Detailed Implementation

[0031] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0032] Example

[0033] An artificially interfaced lithium metal protective layer, comprising a composite material and an adhesive, is formed on a 5μm-15μm substrate surface using a gravure coating machine or a casting coating machine. The substrate is PET, Al foil, or Cu foil, and the coating thickness is 1μm-5μm. The material is transferred to the Li metal surface by roll forming.

[0034] The artificial interface layer comprises a composite material and a binder. The composite material is obtained by ball milling carbon and phosphorus materials under an argon atmosphere. The carbon material is one of phosphated graphite, graphene, hard carbon, fluorinated graphite, graphite oxide, or fullerene, and the phosphorus material is one of red phosphorus or black phosphorus. The ratio of the two materials ranges from 1:2 to 1:5. The composite material accounts for 80%-95% of the total mass of the artificial interface layer. The binder includes one or more of polyvinylidene fluoride, sodium carboxymethyl cellulose, polyvinylidene fluoride-hexafluoropropylene, polyacrylic acid, polyacrylate, and sodium alginate, accounting for 5%-20% of the total mass of the artificial interface layer.

[0035] The method for preparing the above-mentioned artificially interfaced lithium metal protective layer includes the following steps:

[0036] S1. Under an argon atmosphere, weighed carbon material and agate beads are placed in a ball mill jar at a ratio of 1:15-1:25 and ball milled at 300-600 rpm for 7-15 hours to disperse them evenly. Then, phosphorus material is added to the ball mill jar at a ratio of carbon material to phosphorus material of 1:2-1:5 and ball milled at 300-600 rpm for 7-15 hours to disperse it, thus obtaining a composite material. The median particle size range of the composite material obtained after ball milling is 0.8 μm-4 μm.

[0037] S2. Add the composite material to the solvent at a solid content of 10%-30%, and disperse the material for 2-6 hours using a dual planetary mixer at 600-1000 rpm to obtain a uniformly dispersed composite material slurry.

[0038] S3. Add the weighed adhesive to another part of solvent at a solid content of 5%-10%, and disperse it by double planetary stirring at 500rpm-1200rpm for 4h-6h to obtain a uniformly dispersed adhesive solution.

[0039] S4. Add the binder solution prepared in step S3 to the well dispersed slurry prepared in step S2 and further disperse it by double planetary stirring at 500rpm-1200rpm for 1h-5h to obtain the slurry to be coated.

[0040] S5. Using a microgravure coating machine or a cast coating machine, coat the slurry to be coated in step S4 onto the surface of a 5μm-15μm substrate, and heat and dry it in the coating machine oven at 50℃-80℃ to obtain a sample to be transferred with a certain thickness.

[0041] S6. Use a roller press to continuously transfer the sample to be transferred in step S5 to the surface of lithium metal to obtain lithium metal with an artificial interface layer.

[0042] The solvent in steps S2 and S3 is one of dimethylformamide, N-methylpyrrolidone, dimethyl sulfoxide, tetrahydrofuran, or deionized water.

[0043] Example 1

[0044] An artificially interfaced lithium metal protective layer and its preparation method are described, comprising the following steps:

[0045] S1. Under an argon atmosphere, the weighed phosphating graphite material and agate beads were placed in a ball mill jar at a ratio of 1:20 and ball milled at a speed of 500 rpm for 10 hours to disperse them evenly. Then, red phosphorus material was added to the ball mill jar at a ratio of carbon material to phosphorus material of 1:4 and ball milled at a speed of 500 rpm for 12 hours to disperse them evenly, resulting in a composite material with a median particle size of 1.5 μm.

[0046] S2. The obtained composite material is added to N-methylpyrrolidone with a solid content of 15%, and the material is dispersed for 3 hours using a dual planetary mixer at 800 rpm to obtain a uniformly dispersed composite material slurry.

[0047] S3. Add the weighed polyvinylidene fluoride to another part of N-methylpyrrolidone at a solid content of 8%, and disperse at 800 rpm for 5 hours to obtain a uniformly dispersed adhesive solution.

[0048] S4. Add the adhesive solution prepared in step S3 to the well dispersed slurry prepared in step S2, and further disperse it using a dual planetary mixer at 800 rpm for 3 hours to obtain the slurry to be coated.

[0049] S5. The slurry prepared in step S4 is coated onto a 10μm PET surface using a microgravure coating machine, and then dried at 75℃ in the coating machine oven to obtain a 3μm sample to be transferred.

[0050] S6. The sample to be transferred in step S5 is continuously transferred to the lithium metal surface using a roller press to obtain an artificial interface layer. The mass ratio of the composite material and polyvinylidene fluoride in the prepared artificial interface layer is 85% and 15%, respectively.

[0051] Example 2

[0052] An artificially interfaced lithium metal protective layer and its preparation method are described, comprising the following steps:

[0053] S1. Under an argon atmosphere, the weighed fluorinated graphite material and agate beads were placed in a ball mill jar at a ratio of 1:20 and ball milled at a speed of 600 rpm for 10 hours to disperse them evenly. Then, red phosphorus material was added to the ball mill jar at a ratio of carbon material to phosphorus material of 1:5 and ball milled at a speed of 600 rpm for 10 hours to disperse them evenly, resulting in a composite material with a median particle size of 1.0 μm.

[0054] S2. The obtained composite material is added to N-methylpyrrolidone at a solid content of 15%, and the material is dispersed for 6 hours using a dual planetary mixer at 800 rpm to obtain a uniformly dispersed slurry.

[0055] S3. Add the weighed polyvinylidene fluoride to another part of N-methylpyrrolidone at a solid content of 10%, and disperse at 800 rpm for 6 hours to obtain a uniformly dispersed adhesive solution.

[0056] S4. Add the binder solution prepared in step S3 to the well dispersed slurry prepared in step S2, and further disperse it using a dual planetary mixer at 800 rpm for 4 hours to obtain the slurry to be coated.

[0057] S5. The slurry prepared in step S4 is coated onto the surface of a 6μm Cu foil using a microgravure coating machine, and then dried at 75°C in the coating machine oven to obtain a 5μm sample to be transferred.

[0058] S6. The sample to be transferred in step S5 is continuously transferred to the lithium metal surface using a roller press to obtain an artificial interface layer. The mass ratio of the composite material and polyvinylidene fluoride in the prepared artificial interface layer is 83% and 17%, respectively.

[0059] Example 3

[0060] An artificially interfaced lithium metal protective layer and its preparation method are described, comprising the following steps:

[0061] S1. Under an argon atmosphere, weighed graphite oxide material and agate beads were placed in a ball mill jar at a ratio of 1:25 and ball milled at a speed of 600 rpm for 12 hours to disperse them evenly. Then, black phosphorus material was added to the ball mill jar at a ratio of carbon material to phosphorus material of 1:5 and ball milled at a speed of 600 rpm for 14 hours to disperse them evenly, resulting in a composite material with a median particle size of 2.0 μm.

[0062] S2. The obtained composite material is added to tetrahydrofuran with a solid content of 10%, and the material is dispersed for 5 hours using a dual planetary mixer at 600 rpm to obtain a uniformly dispersed slurry.

[0063] S3. Add the weighed vinylidene fluoride-hexafluoropropylene to another part of N-methylpyrrolidone at a solid content of 8%, and disperse at 600 rpm for 4 hours to obtain a uniformly dispersed adhesive solution.

[0064] S4. Add the binder solution prepared in step S3 to the well dispersed slurry prepared in step S2, and further disperse it using a dual planetary mixer at 600 rpm for 2 hours to obtain the slurry to be coated.

[0065] S5. The slurry prepared in step S4 is coated onto the surface of a 6μm Cu foil using a microgravure coating machine, and then dried at 50°C in the coating machine oven to obtain a 5μm sample to be transferred.

[0066] S6. The sample to be transferred in step S5 is continuously transferred to the lithium metal surface using a roller press to obtain an artificial interface layer. The mass ratio of the composite material and vinylidene fluoride-hexafluoropropylene in the prepared artificial interface layer is 90% and 10%, respectively.

[0067] Example 4

[0068] An artificially interfaced lithium metal protective layer and its preparation method are described, comprising the following steps:

[0069] S1. Under an argon atmosphere, the weighed fullerene material and agate beads were placed in a ball mill jar at a ratio of 1:18 and ball milled at a speed of 1000 rpm for 10 hours to disperse them evenly. Then, black phosphorus material was added to the ball mill jar at a ratio of carbon material to phosphorus material of 1:5 and ball milled at a speed of 1000 rpm for 12 hours to disperse them evenly, resulting in a composite material with a median particle size of 1.5 μm.

[0070] S2. The obtained composite material is added to deionized water with a solid content of 18%, and the material is dispersed for 6 hours using a dual planetary mixer at 1000 rpm to obtain a uniformly dispersed slurry.

[0071] S3. Add the weighed sodium carboxymethyl cellulose to another part of deionized water at a solid content of 5%, and disperse it by double planetary stirring at 800 rpm for 3 hours to obtain a uniformly dispersed colloid.

[0072] S4. Add the binder solution prepared in step S3 to the well dispersed slurry prepared in step S2, and further disperse it using a dual planetary mixer at 600 rpm for 3 hours to obtain the slurry to be coated.

[0073] S5. The slurry prepared in step S4 is coated onto the surface of an 8μm Al foil using a microgravure coating machine, and then dried at 60°C in the coating machine oven to obtain a 2μm sample to be transferred.

[0074] S6. The sample to be transferred in step S5 is continuously transferred to the lithium metal surface using a roller press to obtain an artificial interface layer. The mass ratio of the composite material and sodium carboxymethyl cellulose in the prepared artificial interface layer is 93% and 7%, respectively.

[0075] Lithium metal batteries were prepared using the artificial solid-state interface layers for lithium metal protection obtained in Examples 1-4, respectively. The specific steps are as follows:

[0076] Preparation of positive electrode sheet: Lithium nickel cobalt manganese oxide (NCM811), superconducting carbon black (SP) and binder (PVDF) are dispersed in N-methylpyrrolidone solvent at a mass ratio of 97:2:1 with a solid content of 78%. The obtained positive electrode slurry is coated on aluminum foil, dried by blowing air to obtain positive electrode sheet, and its size is cut into 52cm*90cm.

[0077] Preparation of negative electrode: An artificially interfaced lithium metal foil with a thickness of 80 μm was obtained according to the above embodiment as the negative electrode, with a size of 56 cm * 93 cm.

[0078] Preparation of lithium metal batteries: A PE separator with a thickness of 12 μm was used to prepare soft-pack batteries by stacking. The tabs were welded, top-sealed, and side-sealed, and then baked at 60°C for 6 h. In a glove box protected by high-purity argon, an interface wetting agent (1 M LiFSI dissolved in an organic solvent of EC:DEC:DMC = 1:1:1) was added, and the battery was sealed. Finally, the lithium metal battery was obtained by low-rate formation and secondary sealing.

[0079] Fabrication of lithium-lithium symmetric batteries: Button batteries are assembled using two symmetrical pure lithium metal foils and artificially functionalized lithium metal foils.

[0080] Comparative Example 1

[0081] Using the positive electrode sheet prepared above and the untreated lithium metal foil as the negative electrode, a lithium metal soft-pack battery is prepared according to the above lithium metal battery preparation process; using two untreated lithium metal foils according to the above lithium-lithium symmetric battery preparation method, an untreated lithium-lithium symmetric button battery is prepared.

[0082] Example 2

[0083] Using the positive electrode sheet prepared above and the negative electrode of artificially interface-functionalized lithium metal foil, a lithium metal soft-pack battery is prepared according to the above lithium metal battery preparation process; using two artificially interface-functionalized lithium metal foils, a lithium-lithium symmetrical button battery is prepared according to the above lithium-lithium symmetrical battery preparation method.

[0084] Cyclic stability test: Discharge specific capacity at 1C (1C = 180 mA / g relative to NCM811) rate is as follows Figure 2 As shown, the cycling results of the examples and comparative examples show that the lithium metal battery with artificial interface has a higher initial discharge specific capacity and better cycling performance. The examples still have a capacity retention rate of 92.96% after 500 cycles at 1C, while the comparative examples only have 64.37% after 336 cycles at 1C.

[0085] Lithium-lithium symmetric battery cycle test: at 2mA / cm 2 At current density, the stripping / deposition capacity is 2 mAh / cm³. 2 The voltage-time curve of the Li / Li battery is as follows: Figure 3 As shown in the figures, the cycling results of the examples and comparative examples demonstrate that the lithium metal battery with an artificial interface exhibits good cycling stability. The examples show a cycling stability at 2 mAh / cm². 2 It can cycle stably for 450 hours without voltage fluctuations at its capacity, while the comparative example is at 2mAh / cm³. 2 A significant voltage drop was observed after 340 hours of cycling at the specified capacity, indicating that lithium dendrites formed on the electrode surface, causing a micro-short circuit in the battery.

[0086] The above cycle stability test demonstrates that the artificial interface functionalized lithium metal anode prepared by this method has superior cycle performance in lithium metal batteries compared to pure lithium metal anodes.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing an artificially interfaced lithium metal protective layer, characterized in that, Specifically, the following steps are included: S1. Under an argon atmosphere, weighed carbon material and agate beads are placed in a ball mill jar in a certain proportion and dispersed evenly by ball milling; then phosphorus material is added to the ball mill jar and dispersed by ball milling to obtain a composite material. S2. Add the composite material to the solvent according to the determined solid content, and disperse the material using a double planetary mixer to obtain a uniformly dispersed composite material slurry. S3. Add the weighed adhesive to another portion of solvent according to the determined solid content, and disperse it by double planetary stirring to obtain a uniformly dispersed adhesive solution. S4. The adhesive solution prepared in step S3 is added to the well dispersed composite material slurry prepared in step S2 and further dispersed by dual planetary stirring to obtain the slurry to be coated. S5. Use a micro-gravure coating machine or a casting coating machine to coat the coating slurry prepared in step S4 onto the surface of the substrate, and heat and dry it in the coating machine oven to obtain a sample of a certain thickness to be transferred. S6. Use a roller press to continuously transfer the sample to be transferred in step S5 to the surface of lithium metal to obtain lithium metal with an artificial interface layer.

2. The method for preparing an artificially interfaced lithium metal protective layer according to claim 1, characterized in that, The carbon material in step S1 is one of phosphated graphite, graphene, hard carbon, fluorinated graphite, graphite oxide, and fullerene; the ratio of the carbon material to the agate beads in step S1 is in the range of 1:15-1:

25.

3. The method for preparing an artificially interfaced lithium metal protective layer according to claim 1, characterized in that, The phosphorus material in step S1 is either red phosphorus or black phosphorus; the ratio of carbon material to phosphorus material in step S1 is in the range of 1:2 to 1:

5.

4. The method for preparing an artificially interfaced lithium metal protective layer according to claim 1, characterized in that, The median particle size range of the composite material obtained after ball milling in step S1 is 0.8 μm-4 μm.

5. The method for preparing an artificially interfaced lithium metal protective layer according to claim 1, characterized in that, In step S2, the solid content of the composite material is 10%-30%, the double planetary stirring speed is 600rpm-1000rpm, and the time is 2h-6h; in step S3, the solid content of the binder is 5%-10%, the double planetary stirring speed is 500rpm-1200rpm, and the time is 4h-6h.

6. The method for preparing an artificially interfaced lithium metal protective layer according to claim 1, characterized in that, The solvent in steps S2 and S3 is one of dimethylformamide, N-methylpyrrolidone, dimethyl sulfoxide, tetrahydrofuran, and deionized water; the binder in step S3 includes one or more of polyvinylidene fluoride, sodium carboxymethyl cellulose, polyvinylidene fluoride-hexafluoropropylene, polyacrylic acid, polyacrylate, and sodium alginate.

7. The method for preparing an artificially interfaced lithium metal protective layer according to claim 1, characterized in that, The substrate in step S5 includes one of PET, Al foil, and Cu foil, with a thickness of 5μm-15μm; the thickness of the sample to be transferred in step S5 is 1μm-5μm.

8. The method for preparing an artificially interfaced lithium metal protective layer according to claim 1, characterized in that, The heating temperature in step S5 is 50℃-80℃.

9. The method for preparing an artificially interfaced lithium metal protective layer according to claim 1, characterized in that, The composite material accounts for 80%-95% of the total mass of the artificial interface layer, and the binder accounts for 5%-20% of the total mass of the artificial interface layer.

10. An artificially interfaced lithium metal protective layer, characterized in that, The artificially interfaced lithium metal protective layer is prepared by the preparation method according to any one of claims 1-9.

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