A method for preparing a solid-state battery

Abstract

The present invention discloses a method for preparing a solid-state battery, which belongs to the technical field of solid-state batteries. The battery is assembled in an argon glove box in the order of a positive battery shell, a positive electrode sheet, a solid electrolyte, a negative electrode sheet, nickel foam, and a negative battery shell to obtain a solid-state battery. The solid-state electrolyte is an organic-inorganic composite solid-state electrolyte. On the one hand, the flexibility of the organic polymer is used to improve the interface contact. On the other hand, the inorganic material can inhibit the growth of lithium dendrites and the ionic conductivity of the solid-state electrolyte. The obtained modified nano-titanium dioxide has better compatibility with the organic polymer polyvinylidene fluoride than ordinary nano-titanium dioxide, so that the solid-state battery has better cycle performance and has important application value in the field of solid-state battery technology.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid-state batteries, and specifically relates to a method for preparing a solid-state battery. Background Art

[0002] To alleviate the energy crisis and protect the environment, various batteries have become essential. Furthermore, with the rapid development of new energy vehicles, market demands for battery capacity and safety performance are increasing. Lithium-ion batteries, the most commonly used battery on the market, have been widely developed and applied over the past decade due to their high energy density, long cycle life, and excellent reliability.

[0003] Lithium-ion battery electrolytes are mostly organic carbonate solvents, such as ethylene carbonate and propylene carbonate. However, safety issues such as leakage, fire, and explosion caused by traditional liquid electrolytes have seriously hindered the further development of lithium-ion batteries. Solid-state batteries, on the other hand, do not contain liquid. The gaps within and at the interfaces of electrodes and separators are not filled with liquid, and the ion conduction path relies entirely on solid contact. This is a current research hotspot in the battery field. Compared with traditional liquid lithium-ion batteries, they have higher safety and energy density, theoretically exceeding 500Wh / kg. Solid-state electrolytes are non-volatile and non-flammable, greatly improving battery safety.

[0004] Solid-state batteries are safe and have broad prospects. However, because there is no liquid in all-solid-state batteries, the gaps inside and at the interfaces of electrodes and diaphragms are not filled with liquid, and the ion conduction path relies entirely on solid contact, resulting in low ionic conductivity and poor solid-solid interface stability. These problems affect the battery's rate performance and cycle performance. Therefore, there is an urgent need to solve the above problems to meet the higher demands in the field of solid-state battery technology. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defects of the prior art and provide a method for preparing a solid-state battery.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A method for preparing a solid-state battery comprises the following steps:

[0008] The battery is assembled in an argon glove box in the order of positive electrode battery shell, positive electrode plate, solid electrolyte, negative electrode plate, nickel foam, and negative electrode battery shell to obtain a solid-state battery.

[0009] Furthermore, the materials of the positive electrode battery shell and the negative electrode battery shell are both polypropylene.

[0010] Furthermore, the negative electrode plate material is lithium-aluminum alloy.

[0011] Furthermore, the positive electrode plate is prepared by the following steps:

[0012] Polystyrene is dissolved in xylene to obtain a polymer solution, which is then mixed with lithium oxide, conductive carbon black (conductive agent) and polyvinylidene fluoride (binder) to obtain an active slurry. The active slurry is then coated on the surface of aluminum foil, and the positive electrode sheets are obtained through drying, cold pressing and slitting.

[0013] Furthermore, the mass ratio of the polystyrene, lithium oxide, conductive carbon black and polyvinylidene fluoride is 3:8:1:1.

[0014] Furthermore, the solid electrolyte is prepared by the following steps:

[0015] Polyvinylidene fluoride (PVDF) and lithium bis(trifluoromethane)sulfonyl imide were added to N,N-dimethylformamide (DMF) and stirred at room temperature for 8 hours. Subsequently, modified nano-titanium dioxide was added and then magnetically stirred for 8 hours to fully disperse the modified nano-titanium dioxide to obtain a suspension; the suspension was evenly coated on both sides of a 30μm thick cellulose membrane by a doctor blade method, and finally dried in a forced air dryer at 100°C for 6 hours to obtain a solid electrolyte.

[0016] Furthermore, the raw materials are calculated in parts by weight as follows: 40-60 parts of polyvinylidene fluoride, 4-6 parts of lithium bis(trifluoromethane)sulfonimide, and 5-15 parts of modified nano-titanium dioxide.

[0017] The prepared solid electrolyte is an organic-inorganic composite solid electrolyte, in which the organic material is polyvinylidene fluoride, which contains a strong electron-withdrawing group -CF, so it is highly stable to anions, can effectively increase the carrier concentration in the electrolyte system, and can also enhance the mechanical strength and electrochemical stability of the solid electrolyte; the inorganic material is nano-titanium dioxide, an inert inorganic filler, which can not only further improve the mechanical properties of the solid electrolyte, but also reduce the crystallinity of the organic material, thereby improving the ionic conductivity of the solid electrolyte.

[0018] Furthermore, the modified nano titanium dioxide is prepared by the following steps:

[0019] S1. In a three-necked flask, sodium hydroxide solution (30% by mass), anhydrous ethanol, nano-titanium dioxide and lithium nitrate were added to a polytetrafluoroethylene reactor, the reaction temperature was controlled to 180°C, the reaction was carried out for 8 hours, and after the reaction was completed, the mixture was washed with deionized water, then treated under magnetic stirring for 24 hours, and the pH value was adjusted to 7 with hydrochloric acid solution. The mixture was washed again with deionized water, filtered, dried in a 100°C forced air drying oven for 4 hours, and finally placed in a muffle furnace at 400°C for calcination for 2 hours to obtain surface lithiated titanium dioxide nanorods; the ratio of sodium hydroxide solution, anhydrous ethanol, nano-titanium dioxide and lithium nitrate was 20 mL:20 mL:1 g:6.6 g;

[0020] The morphology and composition of nano-titanium dioxide were modified by a hydrothermal method to obtain surface lithiated titanium dioxide nanorods;

[0021] S2. Mix the surface lithiated titanium dioxide nanorods with an ethanol aqueous solution, add the mixture to a magnetic stirring apparatus, add a magnet, start stirring, and disperse for 30 minutes to uniformly disperse the surface lithiated titanium dioxide nanorods in the ethanol aqueous solution. Vacuum the apparatus, introduce N2 gas, add vinyltrimethoxysilane, start heating, set to 80°C, open condensation water, react for 4 hours, complete the reaction, filter, wash with ethanol, and then dry in a vacuum drying oven for 2 hours to obtain intermediate 1; the ratio of the amount of surface lithiated titanium dioxide nanorods, ethanol aqueous solution, and vinyltrimethoxysilane is 1.0 g:100 mL:5.5 g;

[0022] The surface lithiated titanium dioxide nanorods react with vinyltrimethoxysilane to introduce a carbon-carbon double bond to obtain intermediate 1. The specific reaction process is as follows:

[0023] ;

[0024] S3. Add mercaptoacetic acid, p-trifluoromethylaniline, dicyclohexylcarbodiimide (DCC, dehydrating agent) and N,N-dimethylformamide to a three-necked flask equipped with a stirring device, stir and mix well, place in a 40°C water bath, heat in a water bath for 6 hours, complete the reaction, filter, remove the solvent by vacuum distillation, and then purify by column chromatography (eluent using a mixed solvent of benzene / ethyl acetate in a volume ratio of 3:2), remove the eluent by rotary evaporation to obtain intermediate 2; the ratio of mercaptoacetic acid, p-trifluoromethylaniline, dicyclohexylcarbodiimide and N,N-dimethylformamide is 9.2g:16.1g:20.6g:150mL;

[0025] Under the catalysis of DCC, the reaction conditions are relatively mild, and thioglycolic acid and trifluoromethylaniline undergo amidation reaction to obtain intermediate 2. The specific reaction process is as follows:

[0026] ;

[0027] S4. In a three-necked flask equipped with a stirring device, the intermediate 1 was mixed with N,N-dimethylformamide, and ultrasonic treatment was performed for 30 minutes to uniformly disperse the intermediate 1. The intermediate 2 and azobisisobutyronitrile (AIBN) were added, and the reaction temperature was set to 75°C. The reaction was kept warm for 6 hours. Stirring was continued during the reaction until the reaction was completed. The product was distilled under reduced pressure, washed, and freeze-dried to obtain modified nano-titanium dioxide; the ratio of intermediate 1, N,N-dimethylformamide, intermediate 2, and azobisisobutyronitrile was 1g:100mL:6.5g:0.5g;

[0028] Under the action of AIBN, the unsaturated carbon-carbon double bond on intermediate 1 and the thiol group on intermediate 2 undergo a thiol-ene click reaction to obtain modified nano-titanium dioxide. The specific reaction process is as follows:

[0029] ;

[0030] Nano-titanium dioxide is prepared into surface-lithiated titanium dioxide nanorods by a hydrothermal method. After lithiation, the surface of the nano-titanium dioxide becomes rough, forming a particle layer with a certain degree of ionic conductivity, which not only facilitates the interfacial bonding of inorganic and organic materials but also enhances Lewis acid-base reactions. In addition, by further modifying the surface-lithiated titanium dioxide nanorods to graft organic molecular chains, their interfacial effect is improved, which can enhance the compatibility of the nano-titanium dioxide with the organic material polyvinylidene fluoride, making the solid electrolyte more stable. Moreover, the prepared modified nano-titanium dioxide also contains sulfur and C-F bonds. The sulfur element has a low electronegativity and the bonding strength between sulfur and lithium ions is weak, which increases the concentration of free mobile lithium ions. In addition, the radius of sulfur ions is larger than that of oxygen ions, which can provide wider lattice pores for lithium ion migration, thereby enhancing the ionic conductivity of the solid electrolyte. Finally, the introduction of C-F bonds can further enhance the compatibility of nano-titanium dioxide with the organic material polyvinylidene fluoride, so that the performance of the modified nano-titanium dioxide can be fully utilized, significantly enhancing the various properties of the solid electrolyte.

[0031] Beneficial effects of the present invention:

[0032] 1. The electrolyte in the solid-state battery prepared by the present invention is an organic-inorganic composite solid electrolyte. On the one hand, the flexibility of the organic polymer is used to improve the interface contact, and on the other hand, the inorganic material can inhibit the growth of lithium dendrites and enhance the ionic conductivity of the solid electrolyte;

[0033] 2. The modified nano-titanium dioxide prepared has better compatibility with the organic polymer polyvinylidene fluoride than ordinary nano-titanium dioxide, which enables solid-state batteries to have better cycle performance;

[0034] Therefore, the solid-state battery prepared by the present invention has good electrical properties, and the solid electrolyte in the solid-state battery has high ionic conductivity and excellent mechanical properties, and has important application value in the field of solid-state battery technology. DETAILED DESCRIPTION

[0035] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0036] Example 1

[0037] Preparation of modified nano-titanium dioxide:

[0038] S1. In a three-necked flask, 20 mL of sodium hydroxide solution, 20 mL of anhydrous ethanol, 1 g of nano-titanium dioxide and 6.6 g of lithium nitrate were added to a polytetrafluoroethylene reactor, the reaction temperature was controlled to 180°C, and the reaction was carried out for 8 hours. After the reaction was completed, the mixture was washed with deionized water, and then treated under magnetic stirring for 24 hours. The pH value was adjusted to 7 with hydrochloric acid solution, and the mixture was washed again with deionized water, filtered, and dried in a 100°C forced air drying oven for 4 hours. Finally, the mixture was placed in a muffle furnace at 400°C and calcined for 2 hours to obtain surface lithiated titanium dioxide nanorods.

[0039] S2. 1.0 g of surface lithiated titanium dioxide nanorods was mixed with 100 mL of ethanol aqueous solution, added to a magnetic stirring apparatus, a magnet was added, stirring was started, and the mixture was dispersed for 30 min to uniformly disperse the surface lithiated titanium dioxide nanorods in the ethanol aqueous solution. The apparatus was evacuated, N2 gas was introduced, and 5.5 g of vinyltrimethoxysilane was added. Heating was started and set to 80° C., condensing water was turned on, and the reaction was allowed to proceed for 4 h. After the reaction was complete, the mixture was filtered, washed with ethanol, and dried in a vacuum drying oven for 2 h to obtain intermediate 1.

[0040] S3. In a three-necked flask equipped with a stirring device, 9.2 g of thioglycolic acid, 16.1 g of p-trifluoromethylaniline, 20.6 g of dicyclohexylcarbodiimide and 150 mL of N,N-dimethylformamide were added and stirred until uniformly mixed. The mixture was then placed in a 40°C water bath and heated in a water bath for 6 h. After the reaction was completed, the mixture was filtered and the solvent was removed by distillation under reduced pressure. The mixture was then purified by column chromatography (eluent: a mixed solvent of benzene / ethyl acetate in a volume ratio of 3:2). The eluent was removed by rotary evaporation to obtain intermediate 2.

[0041] S4. In a three-necked flask equipped with a stirring device, 1 g of intermediate 1 was mixed with 100 mL of N,N-dimethylformamide, and ultrasonically treated for 30 min to uniformly disperse the intermediate 1. 6.5 g of intermediate 2 and 0.5 g of azobisisobutyronitrile were added. The reaction temperature was set to 75°C and the reaction was kept warm for 6 h. Stirring was continued during the reaction until the reaction was completed. The mixture was distilled under reduced pressure, washed, and freeze-dried to obtain modified nano-titanium dioxide.

[0042] Example 2

[0043] Preparation of modified nano-titanium dioxide:

[0044] S1. In a three-necked flask, 40 mL of sodium hydroxide solution, 40 mL of anhydrous ethanol, 2 g of nano-titanium dioxide and 13.2 g of lithium nitrate were added to a polytetrafluoroethylene reactor, the reaction temperature was controlled to 180°C, and the reaction was carried out for 8 hours. After the reaction was completed, the mixture was washed with deionized water, and then treated under magnetic stirring for 24 hours. The pH value was adjusted to 7 with hydrochloric acid solution, and the mixture was washed again with deionized water, filtered, and dried in a 100°C forced air drying oven for 4 hours. Finally, the mixture was placed in a muffle furnace at 400°C and calcined for 2 hours to obtain surface lithiated titanium dioxide nanorods.

[0045] S2. 2.0 g of surface lithiated titanium dioxide nanorods were mixed with 200 mL of ethanol aqueous solution, added to a magnetic stirring apparatus, a magnet was added, stirring was started, and the mixture was dispersed for 30 min to uniformly disperse the surface lithiated titanium dioxide nanorods in the ethanol aqueous solution. The apparatus was evacuated, N2 gas was introduced, and 11.0 g of vinyltrimethoxysilane was added. Heating was started, set to 80° C., condensation water was turned on, and the reaction was carried out for 4 h. After the reaction was completed, the mixture was filtered, washed with ethanol, and dried in a vacuum drying oven for 2 h to obtain intermediate 1.

[0046] S3. In a three-necked flask equipped with a stirring device, 18.4 g of thioglycolic acid, 32.2 g of p-trifluoromethylaniline, 41.2 g of dicyclohexylcarbodiimide and 300 mL of N,N-dimethylformamide were added and stirred until uniformly mixed. The mixture was placed in a 40°C water bath and heated in a water bath for 6 h. After the reaction was completed, the mixture was filtered and the solvent was removed by distillation under reduced pressure. The mixture was then purified by column chromatography (eluent: a mixed solvent of benzene / ethyl acetate in a volume ratio of 3:2). The eluent was removed by rotary evaporation to obtain intermediate 2.

[0047] S4. In a three-necked flask equipped with a stirring device, 2 g of intermediate 1 was mixed with 200 mL of N,N-dimethylformamide, and ultrasonically treated for 30 min to uniformly disperse the intermediate 1. 13.0 g of intermediate 2 and 1 g of azobisisobutyronitrile were added. The reaction temperature was set to 75 ° C. and the reaction was kept warm for 6 h. Stirring was continued during the reaction until the reaction was completed. The product was distilled under reduced pressure, washed, and freeze-dried to obtain modified nano-titanium dioxide.

[0048] Example 3

[0049] Preparation of solid electrolyte:

[0050] 40 g of polyvinylidene fluoride and 4 g of lithium bis(trifluoromethane)sulfonyl imide were added to 150 mL of N,N-dimethylformamide and stirred at room temperature for 8 h. Subsequently, 5 g of the modified nano-titanium dioxide prepared in Example 1 was added, and then magnetic stirring was carried out for 8 h to fully disperse the modified nano-titanium dioxide to obtain a suspension. The suspension was evenly coated on both sides of a 30 μm thick cellulose film by a doctor blade method, and finally dried in a forced air dryer at 100° C. for 6 h to obtain a solid electrolyte.

[0051] Example 4

[0052] Preparation of solid electrolyte:

[0053] 50 g of polyvinylidene fluoride and 5 g of lithium bis(trifluoromethane)sulfonyl imide were added to 150 mL of N,N-dimethylformamide and stirred at room temperature for 8 h. Subsequently, 10 g of the modified nano-titanium dioxide prepared in Example 2 was added, and then magnetic stirring was carried out for 8 h to fully disperse the modified nano-titanium dioxide to obtain a suspension. The suspension was evenly coated on both sides of a 30 μm thick cellulose film by a doctor blade method, and finally dried in a forced air dryer at 100° C. for 6 h to obtain a solid electrolyte.

[0054] Example 5

[0055] Preparation of solid electrolyte:

[0056] 60 g of polyvinylidene fluoride and 6 g of lithium bis(trifluoromethane)sulfonyl imide were added to 150 mL of N,N-dimethylformamide and stirred at room temperature for 8 h. Subsequently, 15 g of the modified nano-titanium dioxide prepared in Example 2 was added, and then magnetic stirring was carried out for 8 h to fully disperse the modified nano-titanium dioxide to obtain a suspension. The suspension was evenly coated on both sides of a 30 μm thick cellulose film by a doctor blade method, and finally dried in a forced air dryer at 100° C. for 6 h to obtain a solid electrolyte.

[0057] Example 6

[0058] Preparation of positive electrode sheet:

[0059] 3 g of polystyrene was dissolved in 100 mL of xylene to obtain a polymer solution, which was then mixed with 8 g of lithium oxide, 1 g of conductive carbon black, and 1 g of polyvinylidene fluoride (binder) to obtain an active slurry. The active slurry was coated on the surface of aluminum foil, and the positive electrode sheets were obtained by drying, cold pressing, and slitting.

[0060] Example 7

[0061] Preparation of solid-state batteries:

[0062] The battery was assembled in an argon glove box in the order of a positive electrode battery shell, a positive electrode plate prepared in Example 6, a solid electrolyte prepared in Example 3, a negative electrode plate, nickel foam, and a negative electrode battery shell to obtain a solid-state battery;

[0063] The materials of the positive electrode battery shell and the negative electrode battery shell are both polypropylene; the material of the negative electrode plate is lithium aluminum alloy.

[0064] Example 8

[0065] Preparation of solid-state batteries:

[0066] The battery was assembled in an argon glove box in the order of a positive electrode battery shell, a positive electrode sheet prepared in Example 6, a solid electrolyte prepared in Example 4, a negative electrode sheet, nickel foam, and a negative electrode battery shell to obtain a solid-state battery;

[0067] The materials of the positive electrode battery shell and the negative electrode battery shell are both polypropylene; the material of the negative electrode plate is lithium aluminum alloy.

[0068] Example 9

[0069] Preparation of solid-state batteries:

[0070] The battery was assembled in an argon glove box in the order of a positive electrode battery shell, a positive electrode plate prepared in Example 6, a solid electrolyte prepared in Example 5, a negative electrode plate, nickel foam, and a negative electrode battery shell to obtain a solid-state battery;

[0071] The materials of the positive electrode battery shell and the negative electrode battery shell are both polypropylene; the material of the negative electrode plate is lithium aluminum alloy.

[0072] Comparative Example 1

[0073] Ordinary nano-titanium dioxide of the same mass was used to replace the modified nano-titanium dioxide in Example 5, and the remaining steps were the same as in Example 5 to prepare a solid electrolyte.

[0074] Comparative Example 2

[0075] The solid electrolyte prepared in Comparative Example 1 was used to replace the solid electrolyte in Example 9, and the remaining steps were the same as in Example 9 to prepare a solid-state battery.

[0076] The following performance tests were conducted on Examples 3, 4, and 5 and Comparative Example 1 using different test standards:

[0077] The tensile properties were measured using a Meterscotch MTSCMT8535 tensile tester with a frequency of 20 Hz. The test sample was cut into a dumbbell shape with a length of 20 mm, a width of 5 mm, and a thickness of approximately 40 μm.

[0078] Electrochemical impedance spectroscopy was used to measure the ionic conductivity of the solid electrolyte;

[0079] The measured results are shown in Table 1:

[0080] .

[0081] The electrical performance tests were conducted on Example 7, Example 8, Example 9 and Comparative Example 2, and the results are shown in Table 2:

[0082] .

[0083] As can be seen from the above table, the solid-state battery prepared in the embodiment of the present invention has high ionic conductivity and good cycle performance, and the solid electrolyte in the solid-state battery has excellent mechanical properties, and has important application value in the field of solid-state battery technology.

[0084] Throughout the specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0085] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in similar ways. As long as they do not deviate from the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a solid-state battery, characterized in that: The following steps are involved: Assembling the battery in an argon glove box in the order of a positive electrode battery shell, a positive electrode sheet, a solid electrolyte, a negative electrode sheet, nickel foam, and a negative electrode battery shell to obtain a solid-state battery; Wherein, the solid electrolyte is prepared by the following steps: Polyvinylidene fluoride and lithium bis(trifluoromethane)sulfonimide are added to N,N-dimethylformamide and stirred at room temperature, modified nano-titanium dioxide is added, and then stirred to obtain a suspension; the suspension is evenly coated on both sides of a cellulose membrane by a doctor blade method, and dried to obtain a solid electrolyte; Wherein, the modified nano titanium dioxide is prepared by the following steps: S1. Add sodium hydroxide solution, anhydrous ethanol, nano-titanium dioxide and lithium nitrate into a reactor, react at 180°C for 8 hours, wash, stir under magnetic stirring for 24 hours, adjust the pH value to 7, wash again, filter, dry, and finally place in a muffle furnace at 400°C for calcination for 2 hours to obtain surface lithiated titanium dioxide nanorods; S2. Mix the surface lithiated titanium dioxide nanorods with an ethanol aqueous solution, add the mixture to a magnetic stirring apparatus, add a magnet, start stirring, and disperse for 30 minutes. The apparatus is evacuated, nitrogen gas is introduced, and vinyltrimethoxysilane is added. Heating is started, set to 80°C, condensation water is turned on, and the reaction is carried out for 4 hours. After the reaction is complete, the mixture is filtered, washed, and dried to obtain intermediate 1. S3, thioglycolic acid, p-trifluoromethylaniline, dicyclohexylcarbodiimide and N,N-dimethylformamide were stirred and mixed uniformly, and then placed in a 40°C water bath and heated in the water bath for 6 hours. After the reaction was completed, the mixture was filtered, distilled under reduced pressure, purified by column chromatography, and rotary evaporated to obtain intermediate 2; S4. Mix the intermediate 1 with N,N-dimethylformamide, perform ultrasonic treatment for 30 minutes to uniformly disperse the intermediate 1, add the intermediate 2 and azobisisobutyronitrile, and react at 75°C for 6 hours with continuous stirring during the reaction. After the reaction is completed, perform vacuum distillation, washing, and freeze-drying to obtain modified nano-titanium dioxide.

2. The method for preparing a solid-state battery according to claim 1, wherein: In step S1, the ratio of the amount of sodium hydroxide solution, anhydrous ethanol, nano-titanium dioxide, and lithium nitrate is 20 mL: 20 mL: 1 g: 6.6 g.

3. The method for preparing a solid-state battery according to claim 1, wherein: In step S2, the ratio of the surface lithiated titanium dioxide nanorods, the ethanol aqueous solution, and vinyltrimethoxysilane is 1.0 g:100 mL:5.5 g.

4. The method for preparing a solid-state battery according to claim 1, wherein: In step S3, the ratio of thioglycolic acid, p-trifluoromethylaniline, dicyclohexylcarbodiimide, and N,N-dimethylformamide is 9.2 g:16.1 g:20.6 g:150 mL.

5. The method for preparing a solid-state battery according to claim 1, characterized in that: In step S4, the ratio of the amount of intermediate 1, N,N-dimethylformamide, intermediate 2, and azobisisobutyronitrile is 1 g:100 mL:6.5 g:0.5 g.

6. The method for preparing a solid-state battery according to claim 1, characterized in that: The raw materials are calculated in parts by weight as follows: 40-60 parts of polyvinylidene fluoride, 4-6 parts of lithium bis(trifluoromethane)sulfonimide, and 5-15 parts of modified nano-titanium dioxide.

7. The method for preparing a solid-state battery according to claim 1, characterized in that: The positive electrode sheet is prepared by the following steps: Polystyrene is dissolved in xylene to obtain a polymer solution, the polymer solution is mixed with lithium oxide, conductive carbon black and polyvinylidene fluoride to obtain an active slurry, the active slurry is coated on the surface of aluminum foil, and the positive electrode sheet is obtained through drying, cold pressing and slitting.

8. The method for preparing a solid-state battery according to claim 7, characterized in that: The mass ratio of the polystyrene, lithium oxide, conductive carbon black and polyvinylidene fluoride is 3:8:1:1.