Preparation and application of in-situ construction of polymer-inorganic composite negative electrode interface

Abstract

The application belongs to the technical field of all-solid-state battery negative electrode, and discloses a preparation and application of a polymer-inorganic compound negative electrode interface constructed in situ. The preparation method comprises the following steps: dissolving a lithium salt in an organic solvent, adding a polymer monomer and an initiator to stir to form a uniform solution, dropping the solution on the negative electrode side of a sulfide electrolyte block, placing a lithium metal electrode piece to assemble a battery, and then polymerizing to form a compound negative electrode interface through heating. The lithium salt comprises lithium bisfluorosulfonylimide, the organic solvent comprises ethylene glycol dimethyl ether, and the polymer monomer comprises triethylene glycol dimethacrylate. The interface can optimize ion transmission and ensure that the electrode and the electrolyte are in close contact, improve the Young's modulus of the electrolyte, effectively inhibit electrolyte decomposition and lithium dendrite growth, and improve the problem of poor contact, thereby significantly improving the limit current density, cycle stability and rate performance of the battery. The battery process using the method is simple, has high safety and high energy density, and has clear application potential in the field of power batteries.

Description

Technical Field

[0001] This invention belongs to the field of lithium metal anode material technology, specifically relating to the preparation and application of an in-situ constructed polymer-inorganic composite anode interface. Background Technology

[0002] With the surge in demand for high-energy-density energy storage from electric vehicles and portable electronic devices, traditional lithium-ion batteries are approaching their theoretical limits. The thermal runaway risk of liquid electrolytes severely restricts further improvements in battery safety. Against this backdrop, the use of solid-state electrolytes to replace traditional liquid electrolytes and lithium metal as the anode to construct all-solid-state lithium metal batteries is considered a core direction for next-generation battery technology due to its intrinsic safety and high energy density potential. Sulfide solid-state electrolytes possess high ionic conductivity comparable to liquid electrolytes, and their inherent excellent mechanical properties allow for simple cold-pressing processes, simplifying manufacturing. Among anode materials, lithium metal stands out due to its ultra-high theoretical specific capacity and lowest electrochemical potential. Effectively combining lithium metal anodes and solid-state electrolytes solves battery safety issues while achieving capacities exceeding 500 Wh·kg⁻¹. -1 Its high energy density makes sulfide-based all-solid-state lithium metal batteries a strong candidate for next-generation energy storage technology.

[0003] Despite the enormous potential of all-solid-state lithium metal batteries, they still face numerous challenges. The system mainly suffers from the following three problems. First, due to the narrow electrochemical window of the sulfide electrolyte and the low operating potential of lithium metal, the sulfide electrolyte inevitably undergoes continuous decomposition. For example, the reduction products of lithium, phosphorus, sulfur, and chloride are mainly Li₂S, LiCl, and Li₃P, among which Li₂S has an ionic conductivity of only 10. -13 S·cm -1The first problem is the accumulation of byproducts during battery cycling, which increases the impedance at the interface between the electrolyte and the negative electrode, leading to an increase in polarization potential and affecting battery performance. Byproducts of lithium-germanium-phosphorus-sulfur reactions and lithium metal reactions also include lithium-germanium alloys, which have high electronic conductivity, further deteriorating the interface. The second problem is severe lithium dendrite growth. This is because the inherently slow lithium-ion diffusion kinetics in lithium metal lead to uneven lithium deposition and stripping, disrupting the stability of the negative electrode-electrolyte interface. This unstable interface contains pores and voids, causing localized increases in current density and forming "hot spot" regions. Furthermore, the high diffusion rate of lithium ions at the grain boundaries of the solid electrolyte causes lithium dendrites to preferentially grow along these boundaries, ultimately leading to dendrite penetration into the electrolyte. The formation and growth of dendrites can ultimately cause a devastating short circuit inside the battery. The third problem is poor contact between the electrolyte and the negative electrode. During battery cycling, good contact between the electrodes and the electrolyte is necessary to ensure the smooth movement of lithium ions. In liquid lithium-ion batteries, this contact is excellent because the flowable liquid electrolyte completely wets the electrodes, and lithium-ion transport pathways are ubiquitous. However, in all-solid-state batteries, insufficient contact between the solid electrolyte and lithium metal is a significant issue. During solid-state battery fabrication, despite achieving sufficiently high compaction density under high pressure, pressing and sintering lead to the formation of intrinsically non-uniform electrolyte surfaces. Therefore, unlike the complete contact between the electrolyte and the lithium metal anode, the solid electrolyte and lithium metal exhibit point-to-point contact at the interface, resulting in numerous voids and gaps. These defects lengthen lithium-ion transport paths, reduce ion transport rates, and ultimately increase battery impedance, degrading battery performance. Typically, these three problems do not occur independently but rather interact as multiple factors, sometimes even simultaneously.

[0004] Therefore, solving the problem on the negative electrode side is the key to developing sulfide-based all-solid-state batteries. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing an in-situ polymer-inorganic composite negative electrode interface and its application in sulfide-based all-solid-state lithium metal batteries, so as to solve the core problems of existing sulfide-based all-solid-state lithium metal batteries, such as easy decomposition of electrolyte, severe lithium dendrite growth, and poor contact between electrolyte and negative electrode.

[0006] The technical solution adopted by the present invention to achieve the above objectives is as follows:

[0007] A composite negative electrode interface comprising a polymer and an inorganic material.

[0008] Preferably, the polymer monomers include triethylene glycol dimethacrylate or ethylene glycol dimethacrylate.

[0009] Preferably, the inorganic reaction monomers include lithium salts.

[0010] Preferably, the lithium salt includes one of lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, and lithium difluorooxalateborate.

[0011] Preferably, the method for preparing the composite negative electrode interface includes mixing raw materials.

[0012] Preferably, the raw materials include lithium salt, organic solvent, polymerization monomer and initiator.

[0013] Preferably, the raw materials are mixed in a glove box where the water and oxygen content are both less than 0.1 ppm.

[0014] Preferably, the mass-to-volume ratio of lithium salt to organic solvent is 30-80:95mL.

[0015] Preferably, the mass-to-volume ratio of lithium salt to organic polymer monomer is 56.1 g: 2.5-15 mL.

[0016] Preferably, the initiator includes azoisobutyronitrile.

[0017] Preferably, the mass-to-volume ratio of the initiator to the organic polymer monomer is 0.1-0.5 g: 5 mL.

[0018] Preferably, the preparation method of the composite negative electrode interface includes in-situ polymerization.

[0019] Preferably, the conditions for in-situ polymerization include: a heating rate of 1-3℃ / min, and holding at 60-70℃ for 1.5-2.5h.

[0020] Preferably, the in-situ polymerization is carried out in a glove box where the water and oxygen contents are both less than 0.1 ppm.

[0021] The polymer-inorganic composite structure formed by in-situ polymerization can significantly improve the interfacial contact between the lithium metal anode and the sulfide solid electrolyte, filling interfacial voids to reduce contact resistance. The inorganic component has high ionic conductivity, which helps achieve uniform lithium-ion deposition, optimizes the interfacial lithium-ion transport channels, and improves ionic conductivity. The polymer network enhances the interfacial mechanical strength, and its high Young's modulus can physically block lithium dendrite growth, reducing the risk of lithium dendrites piercing the electrolyte. The composite anode interface can inhibit the reductive decomposition of the sulfide electrolyte at low lithium metal potentials, reduce the formation of low-ionic-conductivity byproducts, stabilize the interfacial chemical state, improve the limiting current density of all-solid-state lithium metal batteries, and improve cycle stability and rate performance, helping batteries achieve both high energy density and high safety.

[0022] An all-solid-state lithium metal battery, comprising a lithium metal anode and a solid electrolyte.

[0023] Preferably, the composite anode interface is located between the lithium metal anode and the solid electrolyte.

[0024] Preferably, the solid electrolyte includes a sulfide electrolyte or a sulfide-coated electrolyte.

[0025] Preferably, the sulfide electrolyte includes Li6PS5Cl, Li 10 GeP2S 12 With Li7P3S 11 At least one of them.

[0026] Preferably, the sulfide-coated electrolyte includes a coating agent.

[0027] Preferably, the coating agent comprises methyl 2-phenyloxazole-4-carboxylate and 1,3-bis[3,5-bis(trifluoromethyl)phenyl]thiourea.

[0028] Preferably, the mass ratio of methyl 2-phenyloxazole-4-carboxylate to 1,3-bis[3,5-bis(trifluoromethyl)phenyl]thiourea is 0.8-1.2:1-1.6.

[0029] 2-Phenyroxazole-4-carboxylic acid methyl ester and 1,3-bis[3,5-bis(trifluoromethyl)phenyl]thiourea, as a two-component coating agent, bind to the active sites on the surface of the sulfide electrolyte, adjust the surface energy of the electrolyte, significantly improve its lithiophilicity, promote close contact between lithium metal and electrolyte, and reduce the formation of interfacial voids; stabilize the chemical state of the electrolyte surface, inhibit its reduction decomposition at low lithium metal operating potential, avoid the continuous accumulation of low ionic conductivity byproducts, reduce local current density concentration, and jointly inhibit lithium dendrite nucleation and growth from both chemical and structural levels, ensuring the interfacial stability of the all-solid-state lithium metal battery.

[0030] Preferably, the all-solid-state lithium metal battery includes a composite cathode.

[0031] Preferably, the composite cathode is a composite NCM ternary cathode.

[0032] Preferably, the active material of the composite NCM ternary cathode is LiNi. 0.83 Co 0.12 Mn 0.05 O2.

[0033] Application of a composite negative electrode interface or an all-solid-state lithium metal battery in energy storage devices.

[0034] Preferably, the energy storage device includes one of a power battery for electric vehicles, an energy storage battery for hybrid electric vehicles, and a portable electronic device.

[0035] More preferably, the coating agent includes tert-butylphenylphosphine oxide, and the mass ratio of tert-butylphenylphosphine oxide to 1,3-bis[3,5-bis(trifluoromethyl)phenyl]thiourea is 0.8-1.4:1-1.6. Tert-butylphenylphosphine oxide can regulate the solvation sheath structure of lithium ions at the interface, weaken the binding force of solvent molecules on lithium ions, accelerate the desolvation process of lithium ions, and thus improve the transport kinetic rate of lithium ions between the composite anode interface and the sulfide electrolyte, avoiding local lithium ion enrichment caused by ion transport lag; further, it fills the micropores between electrolyte particles, improves the density and mechanical strength of the electrolyte mass, enhances the physical barrier to lithium dendrite growth, improves the anode interface performance of all-solid-state lithium metal batteries, and ensures the long-cycle stability and high safety of the battery.

[0036] This invention also provides a method for preparing a polymer-inorganic composite solution, comprising:

[0037] Lithium salt is dissolved in an organic solvent and stirred at 200-300 rpm for 5-20 min. Organic polymer monomers and initiators are added and stirred at 200-300 rpm for 5-20 min to obtain a polymer-inorganic composite solution.

[0038] Preferably, the lithium salt includes one of lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, and lithium difluorooxalateborate.

[0039] More preferably, the lithium salt is lithium bis(fluorosulfonyl)imide.

[0040] Preferably, the organic solvent includes ethylene glycol dimethyl ether.

[0041] Preferably, the organic polymer monomer is triethylene glycol dimethacrylate or ethylene glycol dimethacrylate.

[0042] More preferably, the organic polymer monomer is triethylene glycol dimethacrylate.

[0043] Preferably, the initiator includes azoisobutyronitrile.

[0044] Preferably, the mass-to-volume ratio of lithium salt to organic solvent is 30-80:95mL.

[0045] Preferably, the mass-to-volume ratio of lithium salt to organic polymer monomer is 56.1 g: 2.5-15 mL.

[0046] Preferably, the mass-to-volume ratio of the initiator to the organic polymer monomer is 0.1-0.5 g: 5 mL.

[0047] The present invention also provides a method for preparing an electrolyte bulk, comprising:

[0048] The coating agent is dissolved in anhydrous diethyl ether and ultrasonically treated at 250-300W for 10-15 minutes to obtain a pretreated solution. The sulfide electrolyte powder is placed in a polytetrafluoroethylene container and sprayed into the pretreated solution while stirring at 50-70 rpm. The mixture is allowed to stand for 30-50 minutes to allow the anhydrous diethyl ether to completely evaporate, resulting in coated sulfide electrolyte powder. The coated sulfide electrolyte powder or sulfide electrolyte powder is pressed into a block to obtain an electrolyte block.

[0049] Preferably, the coating agent comprises methyl 2-phenyloxazole-4-carboxylate and 1,3-bis[3,5-bis(trifluoromethyl)phenyl]thiourea.

[0050] Preferably, the mass-to-volume ratio of methyl 2-phenyloxazole-4-carboxylic acid to anhydrous diethyl ether is 0.8-1.2 g: 20 mL.

[0051] Preferably, the mass-to-volume ratio of 1,3-bis[3,5-bis(trifluoromethyl)phenyl]thiourea to anhydrous diethyl ether is 1-1.6 g: 20 mL.

[0052] Preferably, the sulfide electrolyte includes Li6PS5Cl, Li 10 GeP2S 12 Li7P3S 11 At least one of them.

[0053] Preferably, the mass of the pretreatment solution is measured by the methyl 2-phenyloxazole-4-carboxylate contained therein, and the mass ratio of sulfide electrolyte to methyl 2-phenyloxazole-4-carboxylate is 22.5:0.01-0.04.

[0054] Preferably, the electrolyte block has a diameter of 10-14 mm and a thickness of 0.7-0.9 mm.

[0055] More preferably, the coating agent includes tert-butylphenylphosphine.

[0056] More preferably, the mass-to-volume ratio of tert-butylphenylphosphine oxide to anhydrous diethyl ether is 0.8-1.4 g: 20 mL.

[0057] This invention also provides a method for preparing a symmetrical battery, comprising:

[0058] A polymer-inorganic composite solution is dropped onto the negative electrode side of an electrolyte block, a lithium metal electrode is placed on the same side, and a lithium metal electrode is placed on the other side. Gaskets and springs are stacked, and the battery is installed in a battery case to obtain an initial symmetrical battery. The initial symmetrical battery is placed in a muffle furnace, and the temperature is raised to 60-70°C at a heating rate of 1-3°C / min. The temperature is held for 1.5-2.5 hours and then cooled to room temperature to obtain a symmetrical battery.

[0059] Preferably, the mass-to-volume ratio of the electrolyte block to the polymer-inorganic composite solution is 22.5 g: 0.5-2 mL.

[0060] Preferably, the diameter of the lithium metal electrode is 10-14 mm.

[0061] This invention also provides a method for preparing a composite positive electrode, comprising:

[0062] The positive electrode active material is mixed with sulfide electrolyte powder, then a polymer-inorganic composite solution is added, and after grinding evenly, it is pressed into a composite positive electrode sheet.

[0063] Preferably, the positive electrode active material includes LiNi. 0.83 Co 0.12 Mn 0.05 O2.

[0064] Preferably, the sulfide electrolyte includes Li 10 GeP2S 12 .

[0065] Preferably, the mass ratio of the positive electrode active material to the sulfide electrolyte powder is 7:1-5.

[0066] Preferably, the mass-to-volume ratio of the positive electrode active material to the polymer-inorganic composite solution is 22.5 g: 0.5-2 mL.

[0067] Preferably, the composite positive electrode sheet has a diameter of 10-14 mm and a thickness of 0.08-0.12 mm.

[0068] This invention also provides a method for preparing a full cell, comprising:

[0069] A polymer-inorganic composite solution is dropped onto the negative electrode side of an electrolyte block, a lithium metal electrode is placed on the same side, and a composite positive electrode is covered on the other side. A gasket and a spring are stacked and encapsulated to obtain an initial full cell. The initial full cell is placed in a muffle furnace and the temperature is raised to 60-70°C at a heating rate of 1-3°C / min. The temperature is held for 1.5-2.5 hours and then cooled to room temperature to obtain a full cell.

[0070] Preferably, the mass-to-volume ratio of the electrolyte block to the polymer-inorganic composite solution is 22.5 g: 0.5-2 mL.

[0071] Preferably, the diameter of the lithium metal electrode is 10-14 mm.

[0072] This invention utilizes lithium bis(fluorosulfonyl)imide as the lithium salt and triethylene glycol dimethacrylate as the monomer to form a polymer-inorganic composite anode interface through in-situ polymerization. Methyl 2-phenyloxazole-4-carboxylate and 1,3-bis[3,5-bis(trifluoromethyl)phenyl]thiourea are used as sulfide electrolyte coating agents to prepare an all-solid-state lithium metal battery. Therefore, it has the following beneficial effects: significantly improving the interfacial contact between the lithium metal anode and the sulfide solid electrolyte, filling interfacial voids to reduce contact impedance; optimizing interfacial lithium-ion transport and improving ionic conductivity, while simultaneously using its high Young's modulus to physically block lithium dendrite growth and inhibit lithium dendrite piercing the electrolyte; reducing the reduction and decomposition of the sulfide electrolyte at low lithium metal potentials, reducing the accumulation of low-ionic-conductivity byproducts, and stabilizing the interfacial chemical state. Therefore, this invention is a method for the in-situ construction and application of a polymer-inorganic composite anode interface that effectively solves the interface problem of sulfide-based all-solid-state lithium metal batteries and significantly improves the performance of all-solid-state lithium metal batteries. Attached Figure Description

[0073] Figure 1 This is a schematic diagram of the limiting current density test results of the symmetrical cell prepared in Example 1.

[0074] Figure 2 This is a schematic diagram of the limiting current density test results of the symmetrical cell prepared in Example 2.

[0075] Figure 3 This is a schematic diagram of the limiting current density test results of the symmetrical cell prepared in Example 3.

[0076] Figure 4 A schematic diagram showing the limiting current density test results of the symmetric cell prepared for Comparative Example 1.

[0077] Figure 5 This is a schematic scanning electron microscope image of the electrolyte block after disassembly of the symmetrical battery prepared in Comparative Example 1.

[0078] Figure 6 This is a schematic scanning electron microscope image of the electrolyte block after disassembly of the symmetrical battery prepared in Example 2.

[0079] Figure 7 This is a schematic diagram of the atomic force microscopy of the electrolyte block after disassembly of the symmetrical battery prepared in Example 2.

[0080] Figure 8 This is a schematic diagram of the atomic force microscopy of the electrolyte block after disassembly of the symmetric battery prepared in Comparative Example 1.

[0081] Figure 9 This is a schematic diagram showing the long-cycle performance test results of the symmetric battery prepared according to the present invention.

[0082] Figure 10This is a schematic diagram showing the rate performance test results of the full cell prepared according to the present invention.

[0083] Figure 11 This is a schematic diagram showing the long-cycle performance test results of the full battery prepared in this invention. Detailed Implementation

[0084] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and 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.

[0085] The concepts involved in this application will first be described with reference to the accompanying drawings. It should be noted that the following descriptions of various concepts are only for the purpose of making the content of this application easier to understand and do not constitute a limitation on the scope of protection of this application; furthermore, the embodiments and features in the embodiments of this application can be combined with each other unless otherwise specified. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0086] Example 1:

[0087] Preparation of the polymer-inorganic composite solution: In a glove box, lithium difluorosulfonyl imide was dissolved in ethylene glycol dimethyl ether and stirred at 250 rpm for 15 min. Triethylene glycol dimethacrylate and azoisobutyronitrile were then added, and the mixture was stirred at 250 rpm for 15 min to obtain the polymer-inorganic composite solution. The mass-to-volume ratio of lithium difluorosulfonyl imide to ethylene glycol dimethyl ether was 56.1 g:95 mL, the mass-to-volume ratio of lithium difluorosulfonyl imide to triethylene glycol dimethacrylate was 56.1 g:5 mL, and the mass-to-volume ratio of azoisobutyronitrile to triethylene glycol dimethacrylate was 0.16 g:5 mL.

[0088] Preparation of electrolyte blocks: The sulfide electrolyte powder was pressed into blocks inside a glove box to obtain electrolyte blocks. The sulfide electrolyte was Li. 10 GeP2S 12 The electrolyte block has a diameter of 12 mm and a thickness of 0.8 mm.

[0089] Preparation of symmetrical cells: In a glove box, a polymer-inorganic composite solution was dropwise added to the negative electrode side of the electrolyte block. A lithium metal electrode was placed on the same side, and a lithium metal electrode was placed on the other side. Gaskets and springs were stacked, and the cells were placed into a CR2032 battery case to obtain an initial symmetrical cell. The initial symmetrical cell was placed in a muffle furnace, and the temperature was raised to 60°C at a heating rate of 1°C / min, held at that temperature for 2 hours, and then cooled to room temperature to obtain the symmetrical cell. The mass-to-volume ratio of the electrolyte block to the polymer-inorganic composite solution was 22.5 g:1 mL, and the diameter of the lithium metal electrode was 12 mm.

[0090] Preparation of the composite positive electrode sheet: In a glove box, the positive electrode active material is mixed with sulfide electrolyte powder, a polymer-inorganic composite solution is added, and after homogenization, it is pressed into a composite positive electrode sheet. The positive electrode active material is LiNi. 0.83 Co 0.12 Mn 0.05 O2, the sulfide electrolyte is Li 10 GeP2S 12 The mass ratio of positive electrode active material to sulfide electrolyte powder is 7:3, the mass-volume ratio of positive electrode active material to polymer-inorganic composite solution is 22.5g:1mL, and the diameter of the composite positive electrode sheet is 12mm and the thickness is 0.1mm.

[0091] Preparation of the full cell: In a glove box, a polymer-inorganic composite solution was dropped onto the negative electrode side of the electrolyte block, a lithium metal electrode was placed on the same side, and a composite positive electrode was placed on the other side. Gaskets and springs were stacked and sealed to obtain the initial full cell. The initial full cell was placed in a muffle furnace, and the temperature was raised to 60°C at a heating rate of 1°C / min, held at that temperature for 2 hours, and then cooled to room temperature to obtain the full cell. The mass-to-volume ratio of the electrolyte block to the polymer-inorganic composite solution was 22.5 g:1 mL, and the diameter of the lithium metal electrode was 12 mm.

[0092] Example 2: The only difference between this example and Example 1 is the preparation of the polymer-inorganic composite solution.

[0093] Preparation of the polymer-inorganic composite solution: In a glove box, lithium difluorosulfonyl imide was dissolved in ethylene glycol dimethyl ether and stirred at 250 rpm for 15 min. Triethylene glycol dimethacrylate and azoisobutyronitrile were then added, and the mixture was stirred at 250 rpm for 15 min to obtain the polymer-inorganic composite solution. The mass-to-volume ratio of lithium difluorosulfonyl imide to ethylene glycol dimethyl ether was 56.1 g:90 mL, the mass-to-volume ratio of lithium difluorosulfonyl imide to triethylene glycol dimethacrylate was 56.1 g:10 mL, and the mass-to-volume ratio of azoisobutyronitrile to triethylene glycol dimethacrylate was 0.16 g:10 mL.

[0094] Example 3: The only difference between this example and Example 1 is the preparation of the polymer-inorganic composite solution.

[0095] Preparation of the polymer-inorganic composite solution: In a glove box, lithium difluorosulfonyl imide was dissolved in ethylene glycol dimethyl ether and stirred at 250 rpm for 15 min. Triethylene glycol dimethacrylate and azoisobutyronitrile were then added, and the mixture was stirred at 250 rpm for 15 min to obtain the polymer-inorganic composite solution. The mass-to-volume ratio of lithium difluorosulfonyl imide to ethylene glycol dimethyl ether was 56.1 g:85 mL, the mass-to-volume ratio of lithium difluorosulfonyl imide to triethylene glycol dimethacrylate was 56.1 g:15 mL, and the mass-to-volume ratio of azoisobutyronitrile to triethylene glycol dimethacrylate was 0.16 g:15 mL.

[0096] Example 4: The only difference between this example and Example 2 is the preparation of the electrolyte block.

[0097] Preparation of electrolyte blocks: In a glove box, methyl 2-phenyloxazole-4-carboxylate and 1,3-bis[3,5-bis(trifluoromethyl)phenyl]thiourea were dissolved in anhydrous diethyl ether and sonicated at 280 W for 12 min to obtain a pretreated solution. The sulfide electrolyte powder was placed in a polytetrafluoroethylene container, and the pretreated solution was sprayed in while stirring at 60 rpm. The mixture was allowed to stand for 40 min to allow the anhydrous diethyl ether to completely evaporate, resulting in coated sulfide electrolyte powder. The coated sulfide electrolyte powder was then pressed into blocks to obtain electrolyte blocks. The mass-to-volume ratio of methyl 2-phenyloxazole-4-carboxylate to anhydrous diethyl ether was 1 g:20 mL, the mass-to-volume ratio of 1,3-bis[3,5-bis(trifluoromethyl)phenyl]thiourea to anhydrous diethyl ether was 1.25 g:20 mL, and the sulfide electrolyte was Li... 10 GeP2S 12 The mass of the pretreatment solution was measured by methyl 2-phenyloxazole-4-carboxylate, the mass ratio of sulfide electrolyte to methyl 2-phenyloxazole-4-carboxylate was 22.5:0.02, and the electrolyte block had a diameter of 12 mm and a thickness of 0.8 mm.

[0098] Example 5: The only difference between this example and Example 2 is the preparation of the electrolyte block.

[0099] Preparation of electrolyte blocks: In a glove box, methyl 2-phenyloxazole-4-carboxylate and 1,3-bis[3,5-bis(trifluoromethyl)phenyl]thiourea were dissolved in anhydrous diethyl ether and sonicated at 280 W for 12 min to obtain a pretreated solution. The sulfide electrolyte powder was placed in a polytetrafluoroethylene container, and the pretreated solution was sprayed in while stirring at 60 rpm. The mixture was allowed to stand for 40 min to allow the anhydrous diethyl ether to completely evaporate, resulting in coated sulfide electrolyte powder. The coated sulfide electrolyte powder was then pressed into blocks to obtain electrolyte blocks. The mass-to-volume ratio of methyl 2-phenyloxazole-4-carboxylate to anhydrous diethyl ether was 1 g:20 mL, the mass-to-volume ratio of 1,3-bis[3,5-bis(trifluoromethyl)phenyl]thiourea to anhydrous diethyl ether was 1.5 g:20 mL, and the sulfide electrolyte was Li... 10 GeP2S 12 The mass of the pretreatment solution was measured by methyl 2-phenyloxazole-4-carboxylate, the mass ratio of sulfide electrolyte to methyl 2-phenyloxazole-4-carboxylate was 22.5:0.02, and the electrolyte block had a diameter of 12 mm and a thickness of 0.8 mm.

[0100] Example 6: The only difference between this example and Example 2 is the preparation of the electrolyte block.

[0101] Preparation of electrolyte blocks: In a glove box, methyl 2-phenyloxazole-4-carboxylate, 1,3-bis[3,5-bis(trifluoromethyl)phenyl]thiourea, and tert-butylphenylphosphine oxide were dissolved in anhydrous diethyl ether and sonicated at 280 W for 12 min to obtain a pretreated solution. The sulfide electrolyte powder was placed in a polytetrafluoroethylene container, and the pretreated solution was sprayed in while stirring at 60 rpm. The mixture was allowed to stand for 40 min to allow the anhydrous diethyl ether to completely evaporate, resulting in coated sulfide electrolyte powder. The coated sulfide electrolyte powder was then pressed into blocks to obtain electrolyte blocks. The mass-to-volume ratio of methyl 2-phenyloxazole-4-carboxylate to anhydrous diethyl ether was 1 g:20 mL, the mass-to-volume ratio of 1,3-bis[3,5-bis(trifluoromethyl)phenyl]thiourea to anhydrous diethyl ether was 1.25 g:20 mL, the mass-to-volume ratio of tert-butylphenylphosphine oxide to anhydrous diethyl ether was 1 g:20 mL, and the sulfide electrolyte was Li... 10 GeP2S 12 The mass of the pretreatment solution was measured by methyl 2-phenyloxazole-4-carboxylate, the mass ratio of sulfide electrolyte to methyl 2-phenyloxazole-4-carboxylate was 22.5:0.02, and the electrolyte block had a diameter of 12 mm and a thickness of 0.8 mm.

[0102] Example 7: The only difference between this example and Example 2 is the preparation of the electrolyte block.

[0103] Preparation of electrolyte blocks: In a glove box, methyl 2-phenyloxazole-4-carboxylate, 1,3-bis[3,5-bis(trifluoromethyl)phenyl]thiourea, and tert-butylphenylphosphine oxide were dissolved in anhydrous diethyl ether and sonicated at 280 W for 12 min to obtain a pretreated solution. The sulfide electrolyte powder was placed in a polytetrafluoroethylene container, and the pretreated solution was sprayed in while stirring at 60 rpm. The mixture was allowed to stand for 40 min to allow the anhydrous diethyl ether to completely evaporate, resulting in coated sulfide electrolyte powder. The coated sulfide electrolyte powder was then pressed into blocks to obtain electrolyte blocks. The mass-to-volume ratio of methyl 2-phenyloxazole-4-carboxylate to anhydrous diethyl ether was 1 g:20 mL, the mass-to-volume ratio of 1,3-bis[3,5-bis(trifluoromethyl)phenyl]thiourea to anhydrous diethyl ether was 1.25 g:20 mL, the mass-to-volume ratio of tert-butylphenylphosphine oxide to anhydrous diethyl ether was 1.25 g:20 mL, and the sulfide electrolyte was Li... 10 GeP2S 12 The mass of the pretreatment solution was measured by methyl 2-phenyloxazole-4-carboxylate, the mass ratio of sulfide electrolyte to methyl 2-phenyloxazole-4-carboxylate was 22.5:0.02, and the electrolyte block had a diameter of 12 mm and a thickness of 0.8 mm.

[0104] Comparative Example 1: The difference between this comparative example and Example 1 lies in the preparation of symmetrical cells and full cells.

[0105] Preparation of symmetrical cells: In a glove box, lithium metal electrodes were placed on one side of the electrolyte block, and spacers and springs were stacked. The mixture was then placed into a CR2032 battery casing to obtain an initial lithium battery. The initial lithium battery was placed in a muffle furnace, and the temperature was raised to 60°C at a heating rate of 1°C / min, held at that temperature for 2 hours, and then cooled to room temperature to obtain a symmetrical cell. The diameter of the lithium metal electrodes was 12 mm.

[0106] Preparation of the full cell: In a glove box, a lithium metal electrode was placed on one side of the electrolyte block, and a composite positive electrode was placed on the other side. Spacers and springs were then stacked and encapsulated to obtain the initial full cell. The initial full cell was placed in a muffle furnace, and the temperature was raised to 60°C at a heating rate of 1°C / min, held at that temperature for 2 hours, and then cooled to room temperature to obtain the full cell. The diameter of the lithium metal electrode was 12 mm.

[0107] Comparative Example 2: The only difference between this comparative example and Example 1 is the preparation of the electrolyte block.

[0108] Preparation of electrolyte blocks: In a glove box, methyl 2-phenyloxazole-4-carboxylate was dissolved in anhydrous diethyl ether and sonicated at 280 W for 12 min to obtain a pretreated solution. Sulfide electrolyte powder was placed in a polytetrafluoroethylene container, and the pretreated solution was sprayed in while stirring at 60 rpm. The mixture was allowed to stand for 40 min to allow the anhydrous diethyl ether to completely evaporate, resulting in coated sulfide electrolyte powder. The coated sulfide electrolyte powder was then pressed into blocks to obtain electrolyte blocks. The mass-to-volume ratio of methyl 2-phenyloxazole-4-carboxylate to anhydrous diethyl ether was 1 g:20 mL, and the sulfide electrolyte was Li... 10 GeP2S 12 The mass of the pretreatment solution was measured by methyl 2-phenyloxazole-4-carboxylate, the mass ratio of sulfide electrolyte to methyl 2-phenyloxazole-4-carboxylate was 22.5:0.02, and the electrolyte block had a diameter of 12 mm and a thickness of 0.8 mm.

[0109] Comparative Example 3: This comparative example differs from Example 1 only in the preparation of the electrolyte block.

[0110] Preparation of electrolyte blocks: In a glove box, 1,3-bis[3,5-bis(trifluoromethyl)phenyl]thiourea was dissolved in anhydrous diethyl ether and sonicated at 280 W for 12 min to obtain a pretreated solution. The sulfide electrolyte powder was placed in a polytetrafluoroethylene container, and the pretreated solution was sprayed in while stirring at 60 rpm. The mixture was allowed to stand for 40 min to allow the anhydrous diethyl ether to completely evaporate, resulting in coated sulfide electrolyte powder. The coated sulfide electrolyte powder was then pressed into blocks to obtain electrolyte blocks. The mass-to-volume ratio of 1,3-bis[3,5-bis(trifluoromethyl)phenyl]thiourea to anhydrous diethyl ether was 1.25 g: 20 mL, and the sulfide electrolyte was Li... 10 GeP2S 12 The mass of the pretreatment solution was measured by the 1,3-bis[3,5-bis(trifluoromethyl)phenyl]thiourea contained therein. The mass ratio of the sulfide electrolyte to 1,3-bis[3,5-bis(trifluoromethyl)phenyl]thiourea was 22.5:0.025. The electrolyte block had a diameter of 12 mm and a thickness of 0.8 mm.

[0111] Experimental Example 1: Limiting Current Density Test of Symmetrical Cells.

[0112] Test samples: Symmetrical cells prepared in each embodiment and comparative example.

[0113] Test method: The Xinwei battery testing system was used to test the limiting current density using the constant current step boost method: starting from a low current density of 0.1 mA·cm⁻¹ -2Initially, each current density was maintained for 1 hour, with 1 hour of charging and 1 hour of discharging constituting one cycle. After the voltage of each cycle stabilized, the current density was gradually increased until the battery overpotential reached 1V, which was considered battery failure. Voltage-time curves under different current densities were recorded, and the highest current density before battery failure was taken as the limiting current density.

[0114] The limiting current density test results of the symmetric cell prepared in Example 1 are as follows: Figure 1 As shown, the limiting current density test results of the symmetric cell prepared in Example 2 are as follows: Figure 2 As shown, the limiting current density test results of the symmetric cell prepared in Example 3 are as follows: Figure 3 As shown, the limiting current density test results of the symmetric cell prepared in Comparative Example 1 are as follows: Figure 4 As shown in Table 1, the limiting current density test results of the symmetric battery prepared by the present invention are shown in Table 1.

[0115] Table 1. Test results of limiting current density of the symmetric battery prepared in this invention.

[0116]

[0117] The polymer-inorganic composite anode interface prepared by this invention can significantly optimize the interfacial electric field distribution, achieving uniform lithium-ion deposition and thus greatly improving the battery's limiting current density. Examples 1-3, by adjusting the amount of triethylene glycol dimethacrylate, alter the crosslinking degree and ion conduction channel structure of the polymer-inorganic composite layer, thereby affecting the uniform distribution of the interfacial electric field and the lithium-ion deposition behavior. In Example 2, the composite layer can form a more suitable ion transport path, resulting in more uniform lithium-ion deposition. Examples 4-5 introduce a two-component coating system composed of methyl 2-phenyloxazole-4-carboxylate and 1,3-bis[3,5-bis(trifluoromethyl)phenyl]thiourea in the preparation of the electrolyte bulk. This two-component system can improve the lithium affinity of the electrolyte surface and reduce interfacial side reactions. Example 5: Adjusting the amount of thiourea further optimizes the interfacial bonding state between the coating layer and lithium metal. Example 6: Based on the two-component coating, tert-butylphenylphosphine oxide is added to form a three-component coating system. Tert-butylphenylphosphine oxide can regulate the solvation structure of lithium ions at the interface, inhibiting the nucleation and growth of lithium dendrites. Adjusting its amount further optimizes the interfacial ionic conductivity, resulting in higher lithium ion transport efficiency. Example 7: Increasing the amount of tert-butylphenylphosphine oxide in the coating system further increases the limiting current density to its maximum. Comparative Example 1: Without using a polymer-inorganic composite solution, a uniform composite interface cannot be constructed between the electrolyte and lithium metal, resulting in uneven distribution of the interfacial electric field. This easily leads to local high current density regions, promoting rapid lithium dendrite growth and premature battery failure. The current density is 0.9 mA·cm⁻¹. -2The overpotential had already reached 1V, which had no practical application value. This indicates that the polymer-inorganic composite negative electrode interface provided by the present invention promotes uniform distribution of the interfacial electric field, achieves uniform lithium deposition, and inhibits the nucleation and growth of lithium dendrites. Comparative Examples 2-3 only used methyl 2-phenyloxazole-4-carboxylate or 1,3-bis[3,5-bis(trifluoromethyl)phenyl]thiourea to coat the electrolyte. A single coating agent is difficult to achieve a dense coating structure, suitable lithium affinity and efficient ion conduction at the same time. It lacks the common regulatory effect between components, and the limiting current density is lower than that of Example 4.

[0118] Experimental Example 2: Scanning electron microscopy test of electrolyte block after disassembly of symmetrical battery.

[0119] Test samples: Symmetrical cells prepared in Example 2 and Comparative Example 1.

[0120] Test method: The symmetrical batteries prepared in Example 2 and Comparative Example 1 were disassembled. The disassembled electrolyte blocks were transferred in a sealed glove box. The surface morphology of the electrolyte blocks was observed using a scanning electron microscope. Before the test, the sample surface was sputtered with gold. The accelerating voltage was 10kV and the magnification was 5000x. The differences in pore structure between the two groups of samples were observed and compared.

[0121] The scanning electron microscope image of the electrolyte block after disassembly of the symmetric battery prepared in Comparative Example 1 is shown below. Figure 5 As shown, the scanning electron microscope image of the electrolyte block after disassembly of the symmetrical battery prepared in Example 2 is as follows. Figure 6 As shown, the electrolyte block of Example 2 has no obvious pores on the composite interface side. The in-situ polymerized composite layer fills the intrinsic pores of the electrolyte, forming a continuous and dense interface structure, which can avoid uneven lithium deposition caused by excessive local current density. The electrolyte block of Comparative Example 1 has obvious pores on its surface and irregular gaps at the interface, which provide channels for lithium dendrite growth.

[0122] Experimental Example 3: Young's modulus test of electrolyte block after disassembly of symmetrical battery.

[0123] Test samples: Symmetrical cells prepared in Example 2 and Comparative Example 1.

[0124] Test method: The symmetric batteries prepared in Example 2 and Comparative Example 1 were disassembled and the Young's modulus of the electrolyte block was tested using atomic force microscopy in nanoindentation mode. Three different test areas were selected on the sample surface, each with an area of ​​2 μm × 2 μm. A constant load of 5 μN was applied, and the relationship between the indentation depth and the load was recorded. The Young's modulus was calculated using the Hertz model, and the average value of the three areas was taken as the final result.

[0125] Atomic force microscopy images of the electrolyte block after disassembly of the symmetric battery prepared in Example 2 are shown below. Figure 7As shown, the atomic force microscopy image of the electrolyte block after disassembly of the symmetric battery prepared in Comparative Example 1 is as follows. Figure 8 As shown in Table 2, the Young's modulus test results of the electrolyte block after disassembly of the symmetrical battery prepared in this invention are shown in Table 2.

[0126] Table 2. Young's modulus test results of electrolyte blocks after disassembly of the symmetric battery prepared in this invention.

[0127]

[0128] This invention significantly improves the Young's modulus of electrolyte blocks and enhances mechanical strength by constructing an in-situ polymer-inorganic composite layer and electrolyte coating system, thereby suppressing lithium dendrite penetration. Examples 1-3 adjust the amount of triethylene glycol dimethacrylate to change the crosslinking density of the polymer-inorganic composite layer; a denser crosslinking structure enhances the deformation resistance of the electrolyte block. Example 2 shows the optimal Young's modulus. Example 4 introduces a two-component coating system of methyl 2-phenyloxazole-4-carboxylate and 1,3-bis[3,5-bis(trifluoromethyl)phenyl]thiourea during electrolyte block preparation. This two-component system forms a continuous coating layer on the surface of electrolyte particles, enhancing interparticle bonding and reducing internal porosity, thus improving the overall mechanical strength of the electrolyte block. Example 5 further optimizes the density of the coating layer by adjusting the amount of thiourea, resulting in an increase in Young's modulus. Examples 6-7 further improve the two-component coating system... Adding tert-butylphenylphosphine oxide to form a three-component coating system allows for stronger interactions with other coating components, further densifying the coating structure and enhancing interfacial bonding with the polymer composite layer. This significantly improves the compressive strength of the electrolyte block and increases Young's modulus. Increasing the amount of tert-butylphenylphosphine oxide can further increase Young's modulus. In Comparative Example 1, no polymer-inorganic composite solution was used, resulting in a lack of mechanical support from the composite layer, weak overall mechanical strength, and a significantly lower Young's modulus, making it difficult to suppress the growth and penetration of lithium dendrites. Comparative Examples 2-3 used only methyl 2-phenyloxazole-4-carboxylate or 1,3-bis[3,5-bis(trifluoromethyl)phenyl]thiourea to coat the electrolyte. The coating layer formed by the single coating agent lacked density and bonding strength, resulting in limited improvement in the mechanical strength of the electrolyte block. The Young's modulus was lower than that of Examples 4-7, making it difficult to effectively resist the mechanical penetration of lithium dendrites.

[0129] Experimental Example 4: Long-cycle performance test of symmetric cells.

[0130] Test samples: Symmetrical cells prepared in Example 2 and Comparative Example 1.

[0131] Test method: The long-term cycle stability was tested using the Xinwei battery testing system in constant current cycling mode: the current density was set to 0.2 mA·cm. -2The unidirectional cycle time is 1 hour, and the cycle continues until the battery overpotential reaches 2V, which is considered a cycle failure. The voltage-time curve during the cycle is recorded.

[0132] The long-cycle performance test results of the symmetric battery prepared by this invention are as follows: Figure 9 As shown, the polymer-inorganic composite solution prepared in Example 2 forms a continuous and dense composite interface between the electrolyte and lithium metal, acting as a physical barrier to inhibit direct contact between lithium metal and sulfide electrolyte, reduce interfacial side reactions and the accumulation of byproducts. The prepared symmetric battery can cycle stably for more than 2000 hours without a significant increase in overpotential. In contrast, the symmetric battery prepared in Comparative Example 1 failed after only 230 hours. Direct contact between lithium metal and sulfide electrolyte triggered severe interfacial side reactions, and the continuous accumulation of byproducts led to a rapid increase in interfacial impedance. This fully demonstrates that the composite interface can significantly reduce interfacial impedance, inhibit interfacial side reactions, and significantly improve the interfacial stability of the battery.

[0133] Test Example 5: Rate performance test of full battery.

[0134] Test samples: Full cells prepared in Example 2 and Comparative Example 1.

[0135] Test method: The Xinwei Battery Test System was used to test the rate performance in a multi-rate stepped cycling mode: The voltage window was set to 2.5-4.3V, and the rate gradient was 0.1C, 0.2C, 0.3C, 0.5C, 0.8C, and 1C. Each rate was cycled 5 times, and finally the cycle returned to 0.2C for 5 times. The discharge specific capacity at different rates was recorded. The capacity retention rate was calculated based on the first discharge capacity at 0.1C.

[0136] The rate performance test results of the full cell prepared by this invention are as follows: Figure 10 As shown, Example 2 optimizes the lithium-ion transport path between the electrolyte and lithium metal, reducing ion transport resistance at the interface. It also reduces the overall impedance of the full battery system through the tight bonding between the composite layer and the electrolyte bulk. Even at a high rate of 1C, lithium ions can still be rapidly and uniformly deposited / deintercalated on the negative electrode surface, avoiding significant capacity decay due to ion transport lag. Therefore, the full battery prepared in Example 2 maintains a high discharge specific capacity at all rates, and its capacity can still be effectively recovered when returning to a 0.2C cycle, demonstrating excellent rate adaptability. Comparative Example 1, without the introduction of the polymer-inorganic composite solution, has a high interface impedance between the electrolyte and lithium metal, resulting in poor lithium-ion transport kinetics. As the rate increases, the interface ion transport lag problem intensifies, and lithium ions cannot be deposited on the negative electrode surface in a timely manner, leading to a significant decrease in discharge specific capacity. Furthermore, the capacity retention rate at high rates is much lower than in Example 2, confirming that the polymer-inorganic composite negative electrode interface can improve the interface ion transport rate and enhance battery reaction kinetics, thereby giving the full battery better rate performance.

[0137] Test Example 6: Long-cycle performance test of full battery.

[0138] Test samples: Full cells prepared in Example 2 and Comparative Example 1.

[0139] Test method: The Newway battery test system was used to test the cycle stability in constant current long cycle mode: the voltage window was set to 2.5-4.3V, the current density was 0.2C, and the cycle was continuously 200 times. The charge and discharge specific capacity and coulombic efficiency of each cycle were recorded. The capacity retention rate after 200 cycles was calculated based on the initial discharge capacity.

[0140] The long-cycle performance test results of the full cell prepared in this invention are as follows: Figure 11 As shown, the polymer-inorganic composite negative electrode interface of the present invention can effectively suppress interfacial side reactions and lithium dendrite growth, significantly improve the long-cycle stability of the full cell, and provide performance support for its application in the field of power batteries.

[0141] The polymer-inorganic composite anode interface in Example 2 stabilizes the anode-side interface, suppresses lithium dendrite growth and interfacial side reactions, and avoids the impact of anode failure on the full-cell cycle. Simultaneously, the composite anode interface fills the intrinsic pores of the electrolyte mass, improving the interfacial contact tightness between the electrolyte and the positive and negative electrodes, reducing impedance increases caused by deteriorating interfacial contact during cycling, and reducing capacity loss. The full cell prepared in Example 2 maintains a high capacity retention rate after 200 cycles, with stable coulombic efficiency and no significant capacity decay. In contrast, Comparative Example 1, lacking the polymer-inorganic composite anode interface, suffers from multiple stability issues: lithium dendrite growth on the anode side increases the risk of electrolyte penetration, and the accumulation of interfacial side reactions exacerbates impedance increases. Furthermore, the interfacial contact between the electrolyte and the electrode gradually deteriorates with cycling, leading to a decrease in lithium-ion transport efficiency and continuous accumulation of capacity loss during each charge-discharge cycle. After 200 cycles, the capacity retention rate is significantly lower than in Example 2, and the coulombic efficiency fluctuates considerably. This fully demonstrates the indispensability of the polymer-inorganic composite anode interface for the long-term cycle stability of the full cell.

[0142] The embodiments and / or implementation methods described above are merely preferred embodiments and / or implementation methods for implementing the technology of the present invention, and are not intended to limit the implementation methods of the technology of the present invention in any way. Any person skilled in the art can make some modifications or alterations to other equivalent embodiments without departing from the scope of the technical means disclosed in the content of the present invention, but they should still be regarded as the technology or embodiments that are substantially the same as the present invention.

[0143] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. The above descriptions are only preferred embodiments of this application. It should be noted that due to the limitations of written expression, while there are objectively infinite specific structures, those skilled in the art can make several improvements, modifications, or changes without departing from the principles of this application, and can also combine the above technical features in an appropriate manner. These improvements, modifications, changes, or combinations, or the direct application of the inventive concept and technical solution to other situations without modification, should all be considered within the scope of protection of this application.

Claims

1. An all-solid-state lithium metal battery, characterized in that: The all-solid-state lithium metal battery includes a composite negative electrode interface, a lithium metal negative electrode and a solid electrolyte, wherein the composite negative electrode interface is located between the lithium metal negative electrode and the solid electrolyte. The solid electrolyte includes a coated sulfide electrolyte, which comprises a coating agent and a sulfide electrolyte, wherein the sulfide electrolyte includes Li6PS5Cl and Li 10 GeP2S 12 With Li7P3S 11 At least one of them; The coating agent is methyl 2-phenyloxazole-4-carboxylate and 1,3-bis[3,5-bis(trifluoromethyl)phenyl]thiourea; the mass ratio of methyl 2-phenyloxazole-4-carboxylate to 1,3-bis[3,5-bis(trifluoromethyl)phenyl]thiourea is 0.8-1.2:1-1.

6.

2. The all-solid-state lithium metal battery according to claim 1, characterized in that: The composite negative electrode interface comprises a polymer and an inorganic substance. The polymer monomers include triethylene glycol dimethacrylate or ethylene glycol dimethacrylate, and the inorganic reactant monomers include a lithium salt, which includes one of lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, and lithium difluorooxalateborate.

3. The all-solid-state lithium metal battery according to claim 1, characterized in that: The preparation method of the composite negative electrode interface includes raw material mixing, wherein the raw materials include lithium salt, organic solvent, polymer monomer and initiator, and the raw material mixing is carried out in a glove box with water and oxygen content of less than 0.1 ppm. The mass-volume ratio of lithium salt to organic solvent is 30-80:95 mL, and the mass-volume ratio of lithium salt to organic polymer monomer is 56.1 g:2.5-15 mL.

4. The all-solid-state lithium metal battery according to claim 3, characterized in that: The initiator includes azoisobutyronitrile, and the mass-to-volume ratio of the initiator to the organic polymer monomer is 0.1-0.5 g: 5 mL.

5. A solid-state lithium metal battery according to claim 1, characterized in that: The preparation method of the composite negative electrode interface includes in-situ polymerization. The conditions for in-situ polymerization include: heating rate of 1-3℃ / min, heating to 60-70℃ and holding at that temperature for 1.5-2.5h. The in-situ polymerization is carried out in a glove box with water and oxygen contents of less than 0.1ppm.

6. The all-solid-state lithium metal battery according to claim 1, characterized in that: The all-solid-state lithium metal battery includes a composite cathode, which is a composite NCM ternary cathode, and the active material of the composite NCM ternary cathode is LiNi. 0.83 Co 0.12 Mn 0.05 O2.

7. The use of an all-solid-state lithium metal battery according to any one of claims 1-6 in an energy storage device, characterized in that: The energy storage device includes one of the following: a power battery for electric vehicles, an energy storage battery for hybrid electric vehicles, and a battery for portable electronic devices.

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