High-temperature-resistant all-solid-state lithium battery and preparation method thereof

Abstract

The application discloses a high-temperature-resistant all-solid-state lithium battery and a preparation method thereof. A polyionic liquid interface layer is arranged between a lithium metal negative electrode and a sulfide solid-state electrolyte, is formed by in-situ solidification of a polyionic liquid precursor solution containing an ionic liquid monomer, a lithium salt and a photoinitiator on the surface of the lithium metal negative electrode, and has a thickness of 2-20 microns. The application solves the problems of poor solid-solid interface contact and interface failure at high temperatures in a sulfide all-solid-state lithium metal battery, maintains excellent interface stability and electrochemical performance in a high-temperature range of 100-150 DEG C, effectively inhibits lithium dendrite growth, reduces interface impedance, and significantly improves the cycle life of the battery. The application also provides a high-temperature-resistant all-solid-state lithium battery containing the interface layer and a preparation method thereof, and the process is simple and the cost is controllable. The all-solid-state lithium battery of the application can work and continuously cycle in a high-temperature environment of 100-150 DEG C, and has a good application prospect in the field of high-temperature energy storage.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, and in particular to a high-temperature resistant all-solid-state lithium battery and its preparation method, specifically a method for improving interfacial contact stability in the high-temperature range of 100~150℃ by in-situ curing a polyionic liquid film on the surface of a lithium metal anode. Background Technology

[0002] With the increasing demands for energy density and safety from electric vehicles and energy storage power stations, traditional liquid lithium batteries are gradually approaching their performance limits due to the flammability and explosiveness of organic electrolytes and the risk of leakage. All-solid-state batteries using non-volatile and non-flammable solid electrolytes are considered an important development direction for next-generation electrochemical energy storage technology. Among these, sulfide solid electrolytes (especially silver-germanium sulfide type Li6PS5Cl, Li...) are... 5.4 PS 4.4 Cl 0.8 Br 0.8 (etc.) due to its high ionic conductivity at room temperature (up to 10). -3 ~10 -2 With its good S / cm and mechanical ductility, it has become one of the most promising solid electrolyte systems for practical application.

[0003] In practical applications, scenarios such as special power supplies, aerospace vehicles, oil well exploration (120~200℃), and high-power fast charging of electric vehicles (80~100℃) all require batteries to operate stably for extended periods at temperatures of 100~150℃ or even higher. However, traditional liquid lithium batteries are prone to electrolyte decomposition, volatilization, and even thermal runaway at high temperatures. While existing all-solid-state batteries offer improved safety, the solid-solid interface between the sulfide electrolyte and the lithium metal anode deteriorates drastically at high temperatures, leading to increased interfacial impedance, exacerbated side reactions, rapid capacity decay, and extremely short cycle life. Currently, there is no mature solution that simultaneously achieves high-temperature interface stability and long-cycle performance. However, sulfide-based all-solid-state lithium metal batteries still face significant challenges in practical applications. First, the rigid solid-solid contact between the sulfide electrolyte and the lithium metal anode leads to poor interfacial contact and high interfacial impedance, severely limiting the battery's power performance and cycle life. Second, the sulfide electrolyte exhibits insufficient chemical / electrochemical stability to the lithium metal anode, and interfacial side reactions (such as reductive decomposition to form Li₂S and Li₃P) further deteriorate the interfacial contact. These problems are amplified dramatically at high temperatures of 100–150°C, and currently, there are no effective solutions, greatly limiting the application prospects of all-solid-state batteries in high-temperature environments.

[0004] CN 119627199 A discloses a sulfide solid electrolyte modified by ionic liquid electrowetting and its application. This method involves coating an ionic liquid onto the surface of a sulfide electrolyte sheet, followed by electrowetting treatment to reduce the interfacial contact angle, improve interfacial wettability, and lower interfacial impedance. However, this technology only coats the liquid ionic liquid onto the interface. At high temperatures (100~150℃), the ionic liquid exhibits increased fluidity, making it prone to leakage and even overflow from the interface, thus failing to maintain the structural and performance stability of the interfacial layer under long-term high-temperature conditions.

[0005] To address interface issues, various interface modification strategies have been proposed in existing technologies. For example, an inert metal layer (such as Au or Ag) can be deposited on the lithium anode surface via magnetron sputtering or evaporation, but this method involves expensive equipment and complex processes. Other studies have employed ionic liquids or polymer electrolytes as buffer layers, but conventional ionic liquid coatings exhibit increased fluidity at high temperatures, leading to leakage and side reactions; while ordinary polymer electrolytes (such as PEO) exhibit poor thermal stability and insufficient ionic conductivity above 100°C. Furthermore, non-in-situ methods, such as pre-forming polymer electrolyte films and then attaching them to the anode surface, cannot achieve tight adhesion with lithium metal, resulting in still relatively high interfacial impedance.

[0006] Therefore, there is an urgent need to develop a polyionic liquid interface layer and its preparation method that is suitable for high-temperature operating conditions of sulfide all-solid-state lithium metal batteries, has a simple process, and exhibits excellent interface stability. Summary of the Invention

[0007] This invention aims to address the shortcomings of existing sulfide-based all-solid-state lithium metal batteries, such as solid-solid interface contact failure, high interface impedance, and poor cycle stability at high temperatures of 100~150℃. It provides a high-temperature resistant all-solid-state lithium battery and its preparation method, which involves in-situ solidification of the lithium metal anode surface induced by ultraviolet light.

[0008] The present invention is achieved as follows: a high-temperature resistant all-solid-state lithium battery includes a lithium metal or lithium alloy negative electrode, a sulfide solid electrolyte membrane and a positive electrode. The all-solid-state lithium battery operates in a high-temperature environment of 100~150℃. A polyionic liquid interface layer is provided between the lithium metal or lithium alloy negative electrode and the sulfide solid electrolyte membrane. The interface layer is formed by in-situ curing of a polyionic liquid precursor solution on the surface of the lithium metal negative electrode by ultraviolet light irradiation. The thickness of the interface layer is 2~20μm. The polyionic liquid precursor solution comprises the following components in parts by weight: 20-80 parts of ionic liquid monomer; 10-50 parts of lithium salt; Photoinitiator 0.1-5 parts; 1-10 parts of crosslinking agent; 10-200 parts of organic solvent.

[0009] Furthermore, the ionic liquid monomer is one or more of imidazole ionic liquid monomers, pyrrolidine ionic liquid monomers, or fluorinated acrylate ionic liquid monomers; The cation of the imidazole ionic liquid monomer is a vinyl or allyl-substituted imidazole cation, and the anion is a bis(trifluoromethanesulfonyl)imide anion, hexafluorophosphate, or tetrafluoroborate. The cation of the pyrrolidine ionic liquid monomer is a vinyl or allyl-substituted pyrrolidine onion cation, and the anion is a bis(trifluoromethanesulfonyl)imide anion, hexafluorophosphate, or tetrafluoroborate. The fluorinated acrylate ionic liquid monomer is a comonomer combination of (meth)acrylate perfluoroalkyl ethyl ester and imidazole or pyrrolidine ionic liquid monomers.

[0010] Furthermore, the imidazole ionic liquid monomer is one or more of 1-vinyl-3-ethylimidazolium bis(trifluoromethanesulfonyl)imide, 1-vinyl-3-butylimidazolium bis(trifluoromethanesulfonyl)imide, or 1-allyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide; The pyrrolidine ionic liquid monomer is one or more of 1-vinyl-3-methylpyrrolidine-onium bis(trifluoromethanesulfonyl)imide, 1-allyl-1-methylpyrrolidine-onium bis(trifluoromethanesulfonyl)imide, or 1-vinyl-3-ethylpyrrolidine-onium bis(trifluoromethanesulfonyl)imide.

[0011] Furthermore, the lithium salt is one or more of lithium bis(trifluoromethanesulfonyl)imide, lithium bisfluorosulfonylimide, lithium hexafluorophosphate, and lithium dioxalate borate; the photoinitiator is one or more of 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexylphenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, benzophenone, and 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone; and the crosslinking agent is one or more of ethylene glycol dimethacrylate and polyethylene glycol diacrylate.

[0012] Furthermore, the sulfide solid electrolyte is a sulfide-germanium ore type Li6PS5Cl, Li6PS5Br, or Li 5.4 PS 4.4 Cl 0.8 Br 0.8 Or its doped or modified materials.

[0013] A method for preparing a high-temperature resistant all-solid-state lithium battery as described above includes the following steps: Step 1: Mix the ionic liquid monomer, lithium salt, photoinitiator and crosslinking agent in proportion, add organic solvent, and stir evenly to obtain precursor solution; Step 2: Coat the surface of the lithium metal or lithium alloy anode with the polyionic liquid precursor solution obtained in Step 1. Step 3: The coated lithium metal anode is cured by irradiation with ultraviolet light. The ultraviolet light wavelength is 200~450nm and the irradiation time is 0.5~20min. A polyionic liquid interface layer is formed in situ on the lithium metal surface. The thickness of the interface layer is 2~20μm. Step 4: Place the lithium anode or lithium alloy anode with the polyionic liquid interface layer in an 80℃ oven and vacuum dry for 2~8 hours. Step 5: Assemble the lithium metal anode or lithium alloy anode with a polyionic liquid interface layer, sulfide solid electrolyte membrane, and positive electrode to obtain a high-temperature resistant all-solid-state lithium battery.

[0014] Furthermore, the coating method in step two includes scraping, spraying, spin coating, or dip coating.

[0015] Compared with the prior art, the present invention has the following beneficial effects: (1) Significantly improves solid-solid interface contact: The polyionic liquid precursor can fully wet the lithium metal and sulfide electrolyte surfaces in the liquid state, and after in-situ curing, it forms a seamless interface layer, which fundamentally solves the problem of poor contact at rigid solid-solid interfaces. Compared with the non-in-situ film formation and re-attachment method, the in-situ cured interface layer has lower interface resistance and better mechanical adhesion.

[0016] (2) Excellent high-temperature stability: Polyionic liquids have a high thermal decomposition temperature (≥300℃) and maintain structural and electrochemical stability within the operating temperature range of 100~150℃. The in-situ polymerization products of pyrrolidine ionic liquid monomers are more conducive to the formation of a stable interfacial passivation layer, effectively suppressing interfacial side reactions at high temperatures.

[0017] (3) Simple process and compatible with existing production lines: The present invention adopts a coating + ultraviolet curing polymerization process, which can achieve large-scale preparation without changing the existing lithium battery electrode coating equipment, and has good process compatibility. Attached Figure Description

[0018] Figure 1 This is a SEM image of the thickness of the polyionic liquid interface layer prepared in Example 1 of the present invention.

[0019] Figure 2 This is a comparison diagram of the interface impedance Nyquist spectra of Embodiment 1 and Comparative Example 1 of the present invention.

[0020] Figure 3 The charge-discharge curve of the high-temperature resistant all-solid-state lithium battery assembled in Embodiment 1 of the present invention at 100°C. Detailed Implementation

[0021] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The following examples are implemented under the premise of the technical solution of the present invention, providing detailed implementation methods and specific operating procedures, which will help those skilled in the art to further understand the present invention. The preferred embodiments described below are only examples; those skilled in the art can conceive of other obvious variations. Any adjustments and improvements made under the concept of the present invention are all within the protection scope of the present invention.

[0022] The high-temperature resistant all-solid-state lithium battery of the present invention includes a lithium metal or lithium alloy negative electrode, a sulfide solid electrolyte membrane, and a positive electrode. The all-solid-state lithium battery operates in a high-temperature environment of 100~150℃. A polyionic liquid interface layer is disposed between the lithium metal or lithium alloy negative electrode and the sulfide solid electrolyte membrane. The interface layer is formed by in-situ curing of a polyionic liquid precursor solution on the surface of the lithium metal negative electrode by ultraviolet light irradiation. The thickness of the interface layer is 2~20μm. The polyionic liquid precursor solution contains the following components in parts by weight: Ionic liquid monomer: 20-80 parts; Lithium salt: 10-50 parts; Photoinitiator: 0.1~5 parts; Optional crosslinking agent: 1 to 10 parts; Optional organic solvent: 10-200 parts.

[0023] The ionic liquid monomer is selected from one or more of the following three categories: (1) Imidazole ionic liquid monomers: the cation is an imidazolium cation substituted with vinyl or allyl groups, and the anion is a bis(trifluoromethanesulfonyl)imide anion (TFSI). - ), hexafluorophosphate (PF6) - ) or tetrafluoroborate (BF4) - Preferably, it is 1-vinyl-3-ethylimidazolium bis(trifluoromethanesulfonyl)imide ([VEIm][TFSI]), 1-vinyl-3-butylimidazolium bis(trifluoromethanesulfonyl)imide ([VBIm][TFSI]) or 1-allyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([AMIm][TFSI]).

[0024] (2) Pyrrolidine ionic liquid monomers: the cation is a vinyl or allyl-substituted pyrrolidine onion cation, and the anion is TFSI - PF6 - Or BF4 -Preferably, it is 1-vinyl-3-methylpyrrolidine-onium bis(trifluoromethanesulfonyl)imide ([VMPyr][TFSI]), 1-allyl-1-methylpyrrolidine-onium bis(trifluoromethanesulfonyl)imide ([AMMPyr][TFSI]), or 1-vinyl-3-ethylpyrrolidine-onium bis(trifluoromethanesulfonyl)imide.

[0025] (3) Fluorinated acrylate ionic liquid monomers: selected from comonomers of perfluoroalkyl ethyl methacrylate and the aforementioned imidazole or pyrrolidine ionic liquid monomers.

[0026] The lithium salt is selected from one or more of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium hexafluorophosphate (LiPF6), and lithium dioxolane borate (LiBOB), preferably LiTFSI or LiFSI.

[0027] The photoinitiator is selected from one or more of 2-hydroxy-2-methyl-1-phenylpropanone (photoinitiator 1173), 1-hydroxycyclohexylphenyl ketone (photoinitiator 184), 2,2-dimethoxy-2-phenylacetophenone (photoinitiator 651), benzophenone (BP), and 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone (photoinitiator 907).

[0028] The crosslinking agent is selected from one or more of ethylene glycol dimethacrylate (EGDMA) and polyethylene glycol diacrylate (PEGDA).

[0029] The organic solvent is selected from one or more of acetonitrile, tetrahydrofuran, N,N-dimethylformamide, and ethylene glycol dimethyl ether.

[0030] The sulfide solid electrolyte is selected from silver-germanium sulfide type Li6PS5Cl, Li6PS5Br, Li 5.4 PS 4.4 Cl 0.8 Br 0.8 Or its doped or modified materials.

[0031] The above-mentioned method for preparing a high-temperature resistant all-solid-state lithium battery includes the following steps: Step 1: Under an inert atmosphere, weigh out the ionic liquid monomer, lithium salt, photoinitiator, crosslinking agent and organic solvent according to the mass fractions, stir evenly to obtain a polyionic liquid precursor solution; Step 2: The polyionic liquid precursor solution obtained in Step 1 is uniformly coated onto the surface of lithium metal or lithium alloy anode. The coating method includes scraping, spraying, spin coating or dip coating. Step 3: The coated lithium metal anode is cured by irradiation with ultraviolet light. The ultraviolet light wavelength is 200~450nm and the irradiation time is 0.5~20min. A polyionic liquid interface layer is formed in situ on the lithium metal surface. The thickness of the interface layer is 2~20μm. Step 4: Place the lithium anode or lithium alloy anode with the polyionic liquid interface layer in an 80℃ oven and vacuum dry for 2~8 hours; Step 5: Assemble the lithium metal anode with a polyionic liquid interface layer, the sulfide solid electrolyte membrane, and the positive electrode to obtain a high-temperature resistant all-solid-state lithium battery.

[0032] Specifically, the method for preparing the high-temperature resistant all-solid-state lithium battery of the present invention includes the following steps: Step 1: In an argon glove box (H2O<0.1ppm, O2<0.1ppm), mix the ionic liquid monomer, lithium salt, photoinitiator and crosslinking agent in proportion, add organic solvent, and stir evenly to obtain a precursor solution; Step 2: Apply the precursor solution to the surface of the lithium metal or lithium alloy anode using a scraping, spraying, or spin coating method; Step 3: Place the coated lithium metal anode under ultraviolet light for curing to form a polyionic liquid interface layer in situ; Step 4: Place the lithium anode with the polyionic liquid interface layer in an 80°C oven for vacuum drying. Step 5: Stack the lithium metal anode with the interface layer, the sulfide solid electrolyte membrane, and the positive electrode in sequence, and apply appropriate pressure to assemble a high-temperature resistant all-solid-state lithium battery.

[0033] Preferably, in step one, the ionic liquid monomer is 1-vinyl-3-methylpyrrolidone bis(trifluoromethanesulfonyl)imide ([VMPyr][TFSI]) or 1-vinyl-3-ethylimidazolium bis(trifluoromethanesulfonyl)imide ([VEIm][TFSI]).

[0034] Preferably, in step one, the lithium salt is LiTFSI, and optionally PEGDA or EGDMA is added as a crosslinking agent.

[0035] Preferably, in step two, the thickness of the wet film is controlled at 5~50μm, and in step three, the thickness of the dry film after curing is 2~20μm.

[0036] Preferably, in step three, the ultraviolet light wavelength is 200~450nm and the irradiation time is 0.5~20min.

[0037] Preferably, in step four, the vacuum drying time is 2 to 8 hours.

[0038] Preferably, in step five, the sulfide solid electrolyte membrane is a self-supporting membrane with a thickness of 10~500μm.

[0039] Preferably, the operating temperature of the high-temperature resistant all-solid-state lithium battery is 100~150℃.

[0040] Example 1 This embodiment provides a method for preparing a high-temperature resistant all-solid-state lithium battery, the steps of which are as follows: 1. In an argon glove box, weigh 5g of 1-vinyl-3-methylpyrrolidone bis(trifluoromethanesulfonyl)imide ([VMPyr][TFSI]), 2g of LiTFSI, 0.1g of photoinitiator 1173, and 0.2g of ethylene glycol dimethacrylate (EGDMA) crosslinking agent. Add 10mL of acetonitrile and stir magnetically for 1 hour until completely dissolved to obtain a polyionic liquid precursor solution.

[0041] 2. Take a lithium metal foil with a thickness of 50 μm and cut it into circular pieces with a diameter of 12 mm. Use a blade coating method to uniformly coat the precursor solution onto the surface of the lithium metal foil, controlling the wet film thickness to be 20 μm.

[0042] 3. The coated lithium metal anode was irradiated under 365nm ultraviolet light for 10 minutes for in-situ curing. After curing, a polyionic liquid interface layer with a thickness of approximately 6μm was formed on the lithium metal surface. Figure 1 As shown.

[0043] 4. Place the lithium metal anode coated with the above polyionic liquid interface layer in an 80°C vacuum oven and dry for 6 hours.

[0044] 5. The lithium metal anode with an interface layer, the silver-germanium sulfide Li6PS5Cl sulfide solid electrolyte membrane (thickness of about 300 μm, prepared by dry pressing), and the NCM811 cathode sheet (load of about 8 mg / cm²) are stacked in sequence and cold-pressed under 200 MPa pressure to assemble a high-temperature resistant all-solid-state battery.

[0045] 6. Performance Testing: Perform AC impedance testing on the assembled all-solid-state battery, such as... Figure 2 As shown, the battery with the polyionic liquid interface layer has an impedance of approximately 17Ω, while the impedance of the control battery (Comparative Example 1) without the interface layer is approximately 130Ω. Constant current charge-discharge tests were conducted on the batteries at 100℃, with a voltage range of 2.8~4.3V. The initial discharge specific capacity at a rate of 0.05C was 204mAh / g. Figure 3 As shown, the capacity retention rate was 91% after 50 cycles and 85% after 100 cycles.

[0046] Example 2 1. In an argon glove box, weigh 5g of 1-vinyl-3-ethylimidazolium bis(trifluoromethanesulfonyl)imide ([VEIm][TFSI]), 2.5g of LiTFSI, 0.1g of photoinitiator 184, and 0.4g of EGDMA crosslinking agent, add 20mL of tetrahydrofuran, and stir magnetically for 1 hour until completely dissolved to obtain a polyionic liquid precursor solution.

[0047] 2. Take a lithium metal foil with a thickness of 50 μm and cut it into circular pieces with a diameter of 12 mm. Use a blade coating method to uniformly coat the precursor solution onto the surface of the lithium metal foil, controlling the wet film thickness to be 30 μm.

[0048] 3. The coated lithium metal anode was irradiated under ultraviolet light with a wavelength of 365nm for 5 minutes for in-situ curing. After curing, a polyionic liquid interface layer with a thickness of about 5μm was formed on the lithium metal surface.

[0049] 4. Place the lithium metal anode coated with the above polyionic liquid interface layer in an 80°C vacuum oven and dry for 4 hours.

[0050] 5. The lithium metal anode with an interface layer, the silver-germanium sulfide Li6PS5Br sulfide solid electrolyte membrane (approximately 250 μm thick, prepared by dry pressing), and the NCM811 cathode sheet (approximately 8 mg / cm² loading) are stacked sequentially and cold-pressed under 200 MPa pressure to assemble a high-temperature resistant all-solid-state battery.

[0051] 6. Performance test results: The initial discharge specific capacity at 100℃ is 203mAh / g, the capacity retention rate is 92% after 50 cycles, and the capacity retention rate is 84% ​​after 100 cycles.

[0052] Example 3 This embodiment is basically the same as Embodiment 2, except that the lithium metal anode is replaced with a lithium-indium (Li-In) alloy foil with a thickness of 50 μm (indium content is 10 wt%), the crosslinking agent is replaced with polyethylene glycol diacrylate (PEGDA), the thickness of the polyionic liquid interface layer is controlled to be 8 μm, and the precursor solution ratio and curing conditions are the same as in Embodiment 1.

[0053] Performance test results: The initial discharge specific capacity at 100℃ was 200mAh / g, the capacity retention rate was 94% after 50 cycles, and the capacity retention rate was 92% after 100 cycles. The synergistic effect of the alloy anode and the polyionic liquid interface layer further improved the interface stability.

[0054] Example 4 This embodiment is basically the same as Example 1, except that the crosslinking agent is replaced with PEGDA and the polyionic liquid interface layer is controlled to be 2μm. The precursor solution ratio and curing conditions are the same as in Example 1.

[0055] Performance test results: The initial discharge specific capacity at 100℃ is 200mAh / g, the capacity retention rate is 87% after 50 cycles, and the capacity retention rate is 76% after 100 cycles.

[0056] Example 5 1. In an argon glove box, weigh 5g of 1-vinyl-3-methylpyrrolidone bis(trifluoromethanesulfonyl)imide ([VMPyr][TFSI]), 2.5g of LiTFSI, 0.1g of photoinitiator 1173, and 0.25g of EGDMA crosslinking agent, add 10mL of tetrahydrofuran, and stir magnetically for 1 hour until completely dissolved to obtain a polyionic liquid precursor solution.

[0057] 2. Take a 50 μm thick lithium-indium (Li-In) alloy foil (indium content 10 wt%) and cut it into 12 mm diameter discs. Use a blade coating method to uniformly coat the precursor solution onto the surface of the lithium metal foil, controlling the wet film thickness to be 40 μm.

[0058] 3. The coated lithium alloy anode was irradiated under ultraviolet light with a wavelength of 395nm for 10 minutes for in-situ curing. After curing, a polyionic liquid interface layer with a thickness of about 10μm was formed on the lithium metal surface.

[0059] 4. The lithium alloy anode coated with the above-mentioned polyionic liquid interface layer is dried in a vacuum oven at 80°C for 4 hours.

[0060] 5. The lithium metal anode with an interface layer, the silver-germanium sulfide Li6PS5Cl sulfide solid electrolyte membrane (thickness of about 400 μm, prepared by dry pressing), and the NCM811 cathode sheet (load of about 8 mg / cm²) are stacked in sequence and cold-pressed under 200 MPa pressure to assemble a high-temperature resistant all-solid-state battery.

[0061] 6. Performance test results: The initial discharge specific capacity at 120℃ is 210mAh / g, the capacity retention rate is 85% after 50 cycles, and the capacity retention rate is 73% after 100 cycles.

[0062] Example 6 This embodiment is basically the same as embodiment 5, except that the thickness of the polyionic liquid interface layer is controlled to be 20 μm and the battery test temperature is adjusted to 135℃.

[0063] Performance test results: The initial discharge specific capacity at 135℃ is 214mAh / g, the capacity retention rate is 75% after 50 cycles, and the capacity retention rate is 60% after 100 cycles.

[0064] Example 7 This embodiment is basically the same as embodiment 5, except that the thickness of the polyionic liquid interface layer is controlled to be 20 μm and the battery test temperature is adjusted to 150℃.

[0065] Performance test results: The initial discharge specific capacity at 150℃ is 219mAh / g, the capacity retention rate is 62% after 50 cycles, and the capacity retention rate is 38% after 100 cycles.

[0066] Comparative Example 1 (No Interface Layer) This comparative example does not include a polyionic liquid interface layer. Instead, the lithium metal anode is directly stacked with a Li6PS5Cl sulfide electrolyte membrane and an NCM811 cathode to assemble the battery. All other conditions are the same as in Example 1.

[0067] Performance test results: The initial discharge specific capacity at 100℃ was 175mAh / g. After 20 cycles, the capacity rapidly decreased to 130mAh / g. After 50 cycles, the capacity retention rate was only 62%, and after 100 cycles, the capacity retention rate was 25%. The battery impedance was much higher than that of Example 1.

[0068] Comparative Example 2 (non-in-situ coated polyionic liquid membrane) This comparative example uses a non-in-situ film formation method: 5g of [VEIm][TFSI] monomer, 3g of LiTFSI, 0.2g of photoinitiator 1173, 0.2g of EGDMA crosslinking agent, and 20ml of tetrahydrofuran are mixed. The above mixed solution is then coated onto the surface of a plastic film and polymerized under 365nm ultraviolet light for 10min, followed by drying in an 80℃ vacuum oven for 4h to form a self-supporting film with a thickness of approximately 10μm, which is then attached to the surface of a lithium metal anode. Other battery preparation processes are the same as in Example 1.

[0069] Performance test results: The initial discharge specific capacity at 100℃ was 188mAh / g, the capacity retention rate was 76% after 50 cycles, and the capacity retention rate was 53% after 100 cycles. Due to the in-situ film formation, tight adhesion could not be achieved, and the interface contact quality was significantly lower than that of Example 1.

[0070] The performance of each embodiment and comparative example is summarized in the table below:

[0071] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A high-temperature resistant all-solid-state lithium battery, comprising a lithium metal or lithium alloy negative electrode, a sulfide solid electrolyte membrane, and a positive electrode, characterized in that, The all-solid-state lithium battery operates in a high-temperature environment of 100~150℃. A polyionic liquid interface layer is provided between the lithium metal or lithium alloy anode and the sulfide solid electrolyte membrane. The interface layer is formed by in-situ curing of a polyionic liquid precursor solution on the surface of the lithium metal anode by ultraviolet light irradiation. The thickness of the interface layer is 2~20μm. The polyionic liquid precursor solution comprises the following components in parts by weight: 20-80 parts of ionic liquid monomer; 10-50 parts of lithium salt; Photoinitiator 0.1-5 parts; 1-10 parts of crosslinking agent; 10-200 parts of organic solvent.

2. The high-temperature resistant all-solid-state lithium battery according to claim 1, characterized in that, The ionic liquid monomer is one or more of imidazole ionic liquid monomers, pyrrolidine ionic liquid monomers, or fluorinated acrylate ionic liquid monomers; The cation of the imidazole ionic liquid monomer is a vinyl or allyl-substituted imidazole cation, and the anion is a bis(trifluoromethanesulfonyl)imide anion, hexafluorophosphate, or tetrafluoroborate. The cation of the pyrrolidine ionic liquid monomer is a vinyl or allyl-substituted pyrrolidine onion cation, and the anion is a bis(trifluoromethanesulfonyl)imide anion, hexafluorophosphate, or tetrafluoroborate. The fluorinated acrylate ionic liquid monomer is a comonomer combination of (meth)acrylate perfluoroalkyl ethyl ester and imidazole or pyrrolidine ionic liquid monomers.

3. The high-temperature resistant all-solid-state lithium battery according to claim 1, characterized in that, The imidazole ionic liquid monomer is one or more of 1-vinyl-3-ethylimidazolium bis(trifluoromethanesulfonyl)imide, 1-vinyl-3-butylimidazolium bis(trifluoromethanesulfonyl)imide, or 1-allyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide; The pyrrolidine ionic liquid monomer is one or more of 1-vinyl-3-methylpyrrolidine-onium bis(trifluoromethanesulfonyl)imide, 1-allyl-1-methylpyrrolidine-onium bis(trifluoromethanesulfonyl)imide, or 1-vinyl-3-ethylpyrrolidine-onium bis(trifluoromethanesulfonyl)imide.

4. The high-temperature resistant all-solid-state lithium battery according to claim 1, characterized in that, The lithium salt is one or more of lithium bis(trifluoromethanesulfonyl)imide, lithium bisfluorosulfonylimide, lithium hexafluorophosphate, and lithium dioxalate borate; the photoinitiator is one or more of 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexylphenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, benzophenone, and 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone; and the crosslinking agent is one or more of ethylene glycol dimethacrylate and polyethylene glycol diacrylate.

5. The high-temperature resistant all-solid-state lithium battery according to claim 1, characterized in that, The sulfide solid electrolyte is a sulfide-germanium ore type Li6PS5Cl, Li6PS5Br, or Li 5.4 PS 4.4 Cl 0.8 Br 0.8 Or its doped or modified materials.

6. A method for preparing a high-temperature resistant all-solid-state lithium battery as described in any one of claims 1-5, characterized in that, Includes the following steps: Step 1: Mix the ionic liquid monomer, lithium salt, photoinitiator and crosslinking agent in proportion, add organic solvent, and stir evenly to obtain precursor solution; Step 2: Coat the surface of the lithium metal or lithium alloy anode with the polyionic liquid precursor solution obtained in Step 1. Step 3: The coated lithium metal anode is cured by irradiation with ultraviolet light. The ultraviolet light wavelength is 200~450nm and the irradiation time is 0.5~20min. A polyionic liquid interface layer is formed in situ on the lithium metal surface. The thickness of the interface layer is 2~20μm. Step 4: Place the lithium anode or lithium alloy anode with the polyionic liquid interface layer in an 80℃ oven and vacuum dry for 2~8 hours. Step 5: Assemble the lithium metal anode or lithium alloy anode with a polyionic liquid interface layer, sulfide solid electrolyte membrane, and positive electrode to obtain a high-temperature resistant all-solid-state lithium battery.

7. The preparation method according to claim 6, characterized in that, The coating methods in step two include scraping, spraying, spin coating, or dip coating.

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