Preparation process of a polymer battery

Abstract

The present invention discloses a preparation process of a polymer battery, belonging to the technical field of polymer batteries. An organic-inorganic composite solid electrolyte is adhered between a positive electrode sheet and a negative electrode sheet to form a battery core, and then the battery core is placed in a battery casing and undergoes sealing, formation, sealing, and packaging to obtain a polymer battery. The polymer electrolyte is an organic-inorganic composite solid electrolyte, which can improve the interfacial contact and enhance the ionic conductivity of the electrolyte; by modifying polyacrylonitrile, its mechanical properties and flame retardancy are better, and it also enhances the ionic conductivity of the electrolyte; therefore, the polymer battery prepared by the present invention has good electrical performance, and the electrolyte in the polymer battery has high ionic conductivity, excellent mechanical properties, and good flame retardancy, and has important application value in the technical field of polymer batteries.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer batteries, and specifically, relates to a preparation process of a polymer battery. Background Art

[0002] Lithium-ion batteries have the advantages of high working voltage, high energy density, small size, no memory effect, and long service life. They are a new type of high-energy battery with higher energy density developed after lead-acid batteries, nickel-cadmium batteries, and nickel-metal hydride batteries, and have witnessed rapid development in the past three decades. Traditional lithium-ion batteries use organic liquid electrolytes such as ethylene carbonate, propylene carbonate and other organic solvents. Such liquid electrolytes can cause safety problems in lithium-ion batteries such as leakage, fire, and explosion. The safety problems of traditional lithium batteries have attracted great attention.

[0003] Polymer batteries, usually referring to lithium polymer batteries (Lithium Polymer Battery, abbreviated as Li-poly or Polymer Battery), are a type of secondary battery. Compared with traditional lithium-ion batteries, they have higher energy density, design flexibility, lighter weight, and better safety performance. The working principle of lithium polymer batteries is similar to that of liquid lithium-ion batteries, and the main difference lies in the different electrolytes. Lithium polymer batteries use solid or colloidal polymer materials as electrolytes instead of liquid electrolytes. This kind of electrolyte is not only safe, but also can conduct lithium ions and act as a separator inside the battery to isolate the positive and negative electrode materials and prevent short circuits. However, there is no liquid in solid-state batteries, and the voids inside and at the interfaces of the electrodes and separators are not filled with liquid. Therefore, the overall rate performance of solid-state polymer batteries is low, the internal resistance is large, and the cycle performance is poor. Moreover, the polymer electrolyte in polymer batteries belongs to polymer materials, and its characteristic of being flammable at high temperatures still brings serious safety hazards to polymer batteries. Competing with ordinary lithium-ion batteries in the traditional market does not have much advantage. Therefore, it is urgent to solve the above problems to meet the higher demands in the technical field of polymer batteries. Summary of the Invention

[0004] The purpose of the present invention is to overcome the defects of the prior art and provide a preparation process of a polymer battery.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A preparation process of a polymer battery includes the following steps:

[0007] Adhere the polymer electrolyte between the positive electrode plate and the negative electrode plate to form an electrode core, and then place the electrode core in a battery housing. After sealing, formation, capping, and packaging, a polymer battery is obtained.

[0008] Further, the negative electrode sheet material is a lithium alloy.

[0009] Further, the positive electrode sheet is prepared by the following steps:

[0010] Put lithium iron phosphate (LEP), polyvinylidene fluoride (binder), and acetylene black (conductive agent) in a mortar and mix them evenly, grind for 0.5 - 1 h, dropwise add N-methylpyrrolidone, and continue grinding until a homogeneous viscosity state is obtained to get the active slurry. Apply the active slurry evenly on the rough surface of the aluminum foil, place it in a vacuum drying oven at 90 °C for 12 h, take it out after it cools down to room temperature, and obtain the positive electrode sheet.

[0011] Further, the mass ratio of lithium iron phosphate, polyvinylidene fluoride, and acetylene black is 6:2:1.

[0012] Further, the polymer electrolyte is prepared by the following steps:

[0013] A1. Place modified polyacrylonitrile, tantalum-doped lithium lanthanum zirconium oxide (LLZTO), and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in an oven at 100 °C for 6 h to remove excess moisture. Then add tantalum-doped lithium lanthanum zirconium oxide to N-methyl-2-pyrrolidone (NMP), and use a crusher for ultrasonic dispersion to disperse some agglomerated tantalum-doped lithium lanthanum zirconium oxide. Then add lithium bis(trifluoromethanesulfonyl)imide and stir for 1 h, add acetic acid to adjust the pH to 7, and then add N,N-dimethylformamide (DMF) and modified polyacrylonitrile and stir for 12 h to obtain a composite electrolyte solution;

[0014] A2. Use the doctor blade method to evenly coat the composite electrolyte solution on both sides of a 30-μm-thick cellulose membrane, and finally dry it in a forced-air dryer at 100 °C for 12 h to obtain the polymer electrolyte.

[0015] Further, the raw materials are as follows by weight: 40 - 60 parts of modified polyacrylonitrile, 10 - 20 parts of tantalum-doped lithium lanthanum zirconium oxide, and 4 - 6 parts of lithium bis(trifluoromethanesulfonyl)imide.

[0016] The prepared polymer electrolyte is doped with inorganic active filler tantalum-doped lithium lanthanum zirconium oxide. This filler can directly participate in ion transport, provide a lithium source, greatly enhance the ionic conductivity of the polymer electrolyte, and adopt an organic / inorganic composite system, which can combine the advantages of both; it improves the interfacial performance, enhances the comprehensive performance of the electrolyte and the rate cycling performance of the polymer battery.

[0017] Further, the modified polyacrylonitrile is prepared by the following steps:

[0018] S1. At room temperature, under nitrogen protection, diphenyl chlorophosphate, 3-buten-1-amine, diethylamine and toluene were stirred and mixed evenly in a three-necked flask equipped with a stirring device. The reaction temperature was controlled at 60 °C and the reaction was carried out under insulation for 5 h. After the reaction was completed, filtration was carried out, and the solvent was removed by distillation under reduced pressure to obtain Intermediate 1. The dosage ratio of diphenyl chlorophosphate, 3-buten-1-amine, diethylamine and toluene was 26.8 g: 7.1 g: 15 mL: 100 mL;

[0019] Nucleophilic substitution occurred between diphenyl chlorophosphate and 3-buten-1-amine, and diethylamine removed the hydrogen chloride generated in the reaction to obtain Intermediate 1. The specific reaction process is shown as follows:

[0020] ;

[0021] S2. In a three-necked flask equipped with a stirring device, Intermediate 1, AIBN (azobisisobutyronitrile) and toluene were stirred and mixed evenly, and 3-mercaptopropanol was slowly added dropwise. After the addition was completed, the reaction temperature was controlled at 70 °C and the reaction was carried out for 4 h. After the reaction was completed, part of the solvent was first removed by rotary evaporation, and then purified by column chromatography (the eluent was a mixed solvent of benzene / ethyl acetate, and the volume ratio of the two was 2:1). The eluent was removed by rotary evaporation to obtain Intermediate 2. The dosage ratio of Intermediate 1, AIBN, toluene and 3-mercaptopropanol was 30.3 g: 0.5 g: 150 mL: 9.2 g;

[0022] Under the action of AIBN, the unsaturated carbon-carbon double bond on the molecule of Intermediate 1 reacted with the mercapto group of 3-mercaptopropanol to carry out a thiol-ene click reaction to obtain Intermediate 2;

[0023] ;

[0024] S3. Polyacrylonitrile powder, zinc acetate dihydrate, ethanolamine and N,N-dimethylformamide were placed in a three-necked flask equipped with a stirrer and a thermometer, and the temperature was gradually raised to 90 °C. After heating was stopped after insulation for 2 h, N,N-dimethylformamide was added for dilution, and then dichloromethane was slowly added while stirring rapidly. After stirring for 10 min, filtration was carried out, and this washing process was repeated 3 times to obtain pre-modified polyacrylonitrile. The dosage ratio of polyacrylonitrile powder, zinc acetate dihydrate, ethanolamine and N,N-dimethylformamide was 20 g: 2 g: 25 g: 200 mL;

[0025] Under the catalysis of zinc acetate dihydrate, the cyano group on the polyacrylonitrile molecule underwent cyclization to form an oxazoline active group, providing a reaction site for subsequent reactions to obtain pre-modified polyacrylonitrile;

[0026] S4. In a three-necked flask equipped with a stirring device, uniformly stir and mix pre-modified polyacrylonitrile, N,N-dimethylformamide, and intermediate 2. Under the condition of 70 °C, keep the temperature for reaction for 2 h. After the reaction is completed, stop heating, then add N,N-dimethylformamide, slowly add toluene while stirring rapidly, filter after stirring for 10 min, and wash repeatedly for 3 times in this way. Place the obtained powder in an oven at 60 °C for drying to obtain modified polyacrylonitrile; the dosage ratio of pre-modified polyacrylonitrile, N,N-dimethylformamide, and intermediate 2 is 20 g:200 mL:35 g;

[0027] The oxazoline active groups in the pre-modified polyacrylonitrile molecules react with the hydroxyl groups in the intermediate 2 molecules to obtain modified polyacrylonitrile;

[0028] Polyacrylonitrile has high electrochemical stability, high ionic conductivity, good thermal stability, a large electrochemical stability window, and good compatibility with lithium electrodes. By modifying polyacrylonitrile, the number of cyano groups in polyacrylonitrile is reduced, making it less likely to react with lithium ions and reducing the formation of compounds such as imines or imides, thereby improving the mechanical properties of the electrolyte; moreover, the modified polyacrylonitrile molecules contain P-N flame retardant components and sulfur elements. Among them, the P-N flame retardant components have the synergistic flame retardant effect of phosphorus-based and nitrogen-based flame retardants, which can greatly improve the flame retardant performance of the electrolyte; the added sulfur element has a lower electronegativity, and the bonding strength between sulfur and lithium ions is weak, increasing the concentration of freely moving lithium ions, and the radius of sulfur ions is larger than that of oxygen ions, so that wider lattice pores can be provided for lithium ion migration. Therefore, it can enhance the ionic conductivity of the solid electrolyte; and the organic molecular chains are connected to the polyacrylonitrile polymer molecules through chemical bonding, improving the long-term stability of the properties of the modified polyacrylonitrile.

[0029] Advantages of the present invention:

[0030] 1. The electrolyte in the polymer 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 electrolyte;

[0031] 2. By modifying polyacrylonitrile, compared with ordinary polyacrylonitrile, its mechanical properties and flame retardant properties are better, and it also enhances the ionic conductivity of the electrolyte;

[0032] Therefore, the polymer battery prepared by the present invention has good electrical performance, and the electrolyte in the polymer battery has high ionic conductivity, excellent mechanical properties, and good flame retardant properties, and has important application value in the field of polymer battery technology. Specific embodiments

[0033] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0034] Example 1

[0035] Preparation of modified polyacrylonitrile:

[0036] S1. At room temperature, under nitrogen protection, 26.8 g of diphenyl chlorophosphate, 7.1 g of 3-buten-1-amine, 15 mL of diethylamine and 100 mL of toluene were stirred and mixed evenly in a three-necked flask equipped with a stirring device. The reaction temperature was controlled at 60 °C, and the reaction was carried out for 5 h with heat preservation. After the reaction was completed, filtration was carried out, and the solvent was removed by reduced pressure distillation to obtain Intermediate 1;

[0037] S2. In a three-necked flask equipped with a stirring device, 30.3 g of Intermediate 1, 0.5 g of AIBN (azobisisobutyronitrile) and 150 mL of toluene were stirred and mixed evenly. 9.2 g of 3-mercaptopropanol was slowly added dropwise. After the addition was completed, the reaction temperature was controlled at 70 °C, and the reaction was carried out for 4 h. After the reaction was completed, part of the solvent was first removed by rotary evaporation, and then purified by column chromatography (the eluent was a mixed solvent of benzene / ethyl acetate, and the volume ratio of the two was 2:1). The eluent was removed by rotary evaporation to obtain Intermediate 2;

[0038] S3. 20 g of polyacrylonitrile powder, 2 g of zinc acetate dihydrate, 25 g of ethanolamine and 100 mL of N,N-dimethylformamide were placed in a three-necked flask equipped with a stirrer and a thermometer. The temperature was gradually raised to 90 °C, and the heating was stopped after 2 h of heat preservation. Then, 100 mL of N,N-dimethylformamide was added for dilution, and 50 mL of dichloromethane was slowly added while stirring rapidly. After stirring for 10 min, filtration was carried out, and this washing process was repeated 3 times to obtain pre-modified polyacrylonitrile;

[0039] S4. 20 g of pre-modified polyacrylonitrile, 100 mL of N,N-dimethylformamide and 35 g of Intermediate 2 were stirred and mixed evenly in a three-necked flask equipped with a stirring device. Under the condition of 70 °C, the reaction was carried out for 2 h with heat preservation. After the reaction was completed, the heating was stopped, and then 200 mL of N,N-dimethylformamide was added. 50 mL of toluene was slowly added while stirring rapidly. After stirring for 10 min, filtration was carried out, and this washing process was repeated 3 times. The obtained powder was dried in an oven at 60 °C to obtain modified polyacrylonitrile.

[0040] Example 2

[0041] Preparation of modified polyacrylonitrile:

[0042] S1. At room temperature, under nitrogen protection, 53.6 g of diphenyl chlorophosphate, 14.2 g of 3-buten-1-amine, 30 mL of diethylamine and 200 mL of toluene were stirred and mixed evenly in a three-necked flask equipped with a stirring device. The reaction temperature was controlled at 60 °C, and the reaction was carried out for 5 h while maintaining the temperature. After the reaction was completed, filtration was carried out, and the solvent was removed by vacuum distillation to obtain Intermediate 1;

[0043] S2. In a three-necked flask equipped with a stirring device, 60.6 g of Intermediate 1, 1.0 g of AIBN (azobisisobutyronitrile) and 300 mL of toluene were stirred and mixed evenly. 18.4 g of 3-mercaptopropanol was slowly added dropwise. After the addition was completed, the reaction temperature was controlled at 70 °C, and the reaction was carried out for 4 h. After the reaction was completed, part of the solvent was removed by rotary evaporation first, and then purified by column chromatography (the eluent was a mixed solvent of benzene / ethyl acetate, and the volume ratio of the two was 2:1). The eluent was removed by rotary evaporation to obtain Intermediate 2;

[0044] S3. 40 g of polyacrylonitrile powder, 4 g of zinc acetate dihydrate, 50 g of ethanolamine and 200 mL of N,N-dimethylformamide were placed in a three-necked flask equipped with a stirrer and a thermometer, and the temperature was gradually raised to 90 °C. After maintaining the temperature for 2 h, heating was stopped. Then, 200 mL of N,N-dimethylformamide was added for dilution, and 100 mL of dichloromethane was slowly added while stirring rapidly. After stirring for 10 min, filtration was carried out, and this washing process was repeated 3 times to obtain pre-modified polyacrylonitrile;

[0045] S4. In a three-necked flask equipped with a stirring device, 40 g of pre-modified polyacrylonitrile, 200 mL of N,N-dimethylformamide and 70 g of Intermediate 2 were stirred and mixed evenly. Under the condition of 70 °C, the reaction was carried out for 2 h while maintaining the temperature. After the reaction was completed, heating was stopped. Then, 200 mL of N,N-dimethylformamide was added, and 100 mL of toluene was slowly added while stirring rapidly. After stirring for 10 min, filtration was carried out, and this washing process was repeated 3 times. The obtained powder was dried in an oven at 60 °C to obtain modified polyacrylonitrile.

[0046] Example 3

[0047] Preparation of Polymer Electrolyte:

[0048] A1. 40 g of the modified polyacrylonitrile prepared in Example 1, 10 g of tantalum-doped lithium lanthanum zirconium oxide and 4 g of lithium bis(trifluoromethanesulfonyl)imide were placed in an oven at 100 °C and dried for 6 h to remove excess moisture. Then, the tantalum-doped lithium lanthanum zirconium oxide was added to N-methyl-2-pyrrolidone, and ultrasonic dispersion was carried out using a crusher to disperse part of the agglomerated tantalum-doped lithium lanthanum zirconium oxide. Then, lithium bis(trifluoromethanesulfonyl)imide was added and stirred for 1 h, and then acetic acid was added to adjust the pH to 7. Then, 100 mL of N,N-dimethylformamide and the modified polyacrylonitrile were added and stirred for 12 h to obtain a composite electrolyte solution;

[0049] A2. Apply the composite electrolyte solution evenly on both sides of a 30-μm-thick cellulose membrane by the doctor blade method, and finally dry it in a forced-air dryer at 100 °C for 12 h to obtain the polymer electrolyte.

[0050] Example 4

[0051] Preparation of polymer electrolyte:

[0052] A1. Place 50 g of the modified polyacrylonitrile prepared in Example 2, 15 g of tantalum-doped lithium lanthanum zirconium oxide, and 5 g of lithium bis(trifluoromethanesulfonyl)imide in an oven at 100 °C for 6 h to remove excess moisture. Then add the tantalum-doped lithium lanthanum zirconium oxide to N-methyl-2-pyrrolidone and perform ultrasonic dispersion using a crusher to disperse some of the agglomerated tantalum-doped lithium lanthanum zirconium oxide. Then add lithium bis(trifluoromethanesulfonyl)imide and stir for 1 h, add acetic acid to adjust the pH to 7, and then add 150 mL of N,N-dimethylformamide and the modified polyacrylonitrile and stir for 12 h to obtain the composite electrolyte solution;

[0053] A2. Apply the composite electrolyte solution evenly on both sides of a 30-μm-thick cellulose membrane by the doctor blade method, and finally dry it in a forced-air dryer at 100 °C for 12 h to obtain the polymer electrolyte.

[0054] Example 5

[0055] Preparation of polymer electrolyte:

[0056] A1. Place 60 g of the modified polyacrylonitrile prepared in Example 2, 20 g of tantalum-doped lithium lanthanum zirconium oxide, and 6 g of lithium bis(trifluoromethanesulfonyl)imide in an oven at 100 °C for 6 h to remove excess moisture. Then add the tantalum-doped lithium lanthanum zirconium oxide to N-methyl-2-pyrrolidone and perform ultrasonic dispersion using a crusher to disperse some of the agglomerated tantalum-doped lithium lanthanum zirconium oxide. Then add lithium bis(trifluoromethanesulfonyl)imide and stir for 1 h, add acetic acid to adjust the pH to 7, and then add 100 mL of N,N-dimethylformamide and the modified polyacrylonitrile and stir for 12 h to obtain the composite electrolyte solution;

[0057] A2. Apply the composite electrolyte solution evenly on both sides of a 30-μm-thick cellulose membrane by the doctor blade method, and finally dry it in a forced-air dryer at 100 °C for 12 h to obtain the polymer electrolyte.

[0058] Example 6

[0059] Preparation of the positive electrode plate:

[0060] 6 g of lithium iron phosphate, 2 g of polyvinylidene fluoride, and 1 g of acetylene black were placed in a mortar and mixed evenly, ground for 0.5 h, 50 mL of N-methylpyrrolidone was added dropwise, and grinding was continued until a uniform viscosity state was obtained to obtain an active slurry. The active slurry was evenly applied on the rough surface of the aluminum foil and placed in a vacuum drying oven at 90 °C for 12 h. After it cooled to room temperature, it was taken out to obtain a positive electrode plate.

[0061] Example VII

[0062] Prepare a polymer battery:

[0063] The polymer electrolyte prepared in Example III was adhered between the positive electrode plate and the negative electrode plate prepared in Example VI to form a core. Then, the core was placed in a battery casing and subjected to sealing, formation, capping, and packaging to obtain a polymer battery;

[0064] The negative electrode plate material is a lithium alloy.

[0065] Example VIII

[0066] Prepare a polymer battery:

[0067] The polymer electrolyte prepared in Example IV was adhered between the positive electrode plate and the negative electrode plate prepared in Example VI to form a core. Then, the core was placed in a battery casing and subjected to sealing, formation, capping, and packaging to obtain a polymer battery;

[0068] The negative electrode plate material is a lithium alloy.

[0069] Example IX

[0070] Prepare a polymer battery:

[0071] The polymer electrolyte prepared in Example V was adhered between the positive electrode plate and the negative electrode plate prepared in Example VI to form a core. Then, the core was placed in a battery casing and subjected to sealing, formation, capping, and packaging to obtain a polymer battery;

[0072] The negative electrode plate material is a lithium alloy.

[0073] Comparative Example I

[0074] Ordinary polyacrylonitrile of the same mass was used to replace the modified polyacrylonitrile in Example V, and the remaining steps were the same as those in Example V to prepare a polymer electrolyte.

[0075] Comparative Example II

[0076] The polymer electrolyte prepared in Comparative Example I was used to replace the polymer electrolyte in Example IX, and the remaining steps were the same as those in Example IX to prepare a polymer battery.

[0077] Perform the following performance tests on Examples 3, 4, 5 and Comparative Example 1 with different test standards:

[0078] Use a MTS CMT8535 tensile tester from MTS. Cut the test sample into a dumbbell shape with a length of 20 mm, a width of 5 mm, and a thickness of about 40 μm. Measure the tensile properties at a frequency of 20 Hz.

[0079] Measure the ionic conductivity of the solid electrolyte by electrochemical impedance spectroscopy.

[0080] Use the national standard GB / T 2406-2008 "Test Method for Combustion Performance of Plastics" to measure the limiting oxygen index of the test sample before and after standing at room temperature for 180 days.

[0081] The measured results are shown in Table 1:

[0082] Table 1

[0083]

[0084] Perform electrical property tests on Example 7, Example 8, Example 9 and Comparative Example 2. The measured results are shown in Table 2:

[0085] Table 2

[0086]

[0087] As can be seen from the above two tables, the polymer battery prepared in the examples of the present invention has good electrical properties, and the electrolyte in the polymer battery has high ionic conductivity, excellent mechanical properties, and good flame retardant properties, and has important application value in the field of polymer battery technology.

[0088] In the description of the specification, the description referring to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0089] The above content is only an example and explanation of the present invention. Those skilled in the art of the present technology can make various modifications or supplements to the described specific embodiments or use similar methods for substitution, as long as they do not deviate from the invention or exceed the scope defined by the claims of the present invention, they should all belong to the protection scope of the present invention.

Claims

1. A preparation process of a polymer battery, characterized in that, It includes the following steps: Adhere the polymer electrolyte between the positive electrode sheet and the negative electrode sheet to form a core, then place the core in a battery case, and after sealing, formation, capping, and packaging, a polymer battery is obtained; Among them, the polymer electrolyte is prepared through the following steps: A1. Dry the modified polyacrylonitrile, tantalum-doped lithium lanthanum zirconium oxide, and lithium bis(trifluoromethanesulfonyl)imide, then add the tantalum-doped lithium lanthanum zirconium oxide into N-methyl-2-pyrrolidone, perform ultrasonic dispersion using a crusher, then add lithium bis(trifluoromethanesulfonyl)imide and stir, adjust the pH to 7, and then add N,N-dimethylformamide and the modified polyacrylonitrile and stir to obtain a composite electrolyte solution; A2. Use the doctor blade method to evenly coat the composite electrolyte solution on both sides of a 30-μm-thick cellulose membrane, and dry to obtain the polymer electrolyte; Among them, the modified polyacrylonitrile is prepared through the following steps: S1. At room temperature, under nitrogen protection, stir and mix diphenyl chlorophosphate, 3-buten-1-amine, diethylamine, and toluene, react at 60 °C for 5 h, after the reaction is completed, filter, and perform vacuum distillation to obtain intermediate 1; S2. Stir and mix intermediate 1, azobisisobutyronitrile, and toluene evenly, dropwise add 3-mercaptopropanol, react at 70 °C for 4 h, after the reaction ends, perform rotary evaporation, purify by column chromatography, and perform rotary evaporation to obtain intermediate 2; S3. Place polyacrylonitrile powder, zinc acetate dihydrate, ethanolamine, and N,N-dimethylformamide in a three-necked flask, gradually heat up to 90 °C, keep warm for 2 h and then stop heating, then add N,N-dimethylformamide for dilution, and while rapidly stirring, slowly add dichloromethane, stir for 10 min and then filter, and repeat this washing process 3 times to obtain pre-modified polyacrylonitrile; S4. Stir and mix the pre-modified polyacrylonitrile, N,N-dimethylformamide, and intermediate 2 evenly, under the condition of 70 °C, keep warm and react for 2 h, after the reaction is completed, then stop heating, add N,N-dimethylformamide again, while rapidly stirring, slowly add toluene, stir for 10 min and then filter, and repeat this washing process 3 times, and dry to obtain the modified polyacrylonitrile.

2. The preparation process of a polymer battery according to claim 1, wherein, In step S1, the dosage ratio of diphenyl chlorophosphate, 3-buten-1-amine, diethylamine, and toluene is 26.8 g:7.1 g:15 mL:100 mL.

3. The preparation process of a polymer battery according to claim 1, characterized in that, In step S2, the dosage ratio of intermediate 1, azobisisobutyronitrile, toluene, and 3-mercaptopropanol is 30.3 g:0.5 g:150 mL:9.2 g.

4. The preparation process of a polymer battery according to claim 1, characterized in that, In step S3, the dosage ratio of polyacrylonitrile powder, zinc acetate dihydrate, ethanolamine, and N,N-dimethylformamide is 20 g:2 g:25 g:200 mL.

5. The preparation process of a polymer battery according to claim 1, wherein, In step S4, the dosage ratio of the pre-modified polyacrylonitrile, N,N-dimethylformamide, and intermediate 2 is 20 g:200 mL:35 g.

6. The preparation process of a polymer battery according to claim 1, characterized in that, The amounts of each raw material are as follows by weight parts: 40-60 parts of modified polyacrylonitrile, 10-20 parts of tantalum-doped lithium lanthanum zirconium oxide, and 4-6 parts of lithium bis(trifluoromethanesulfonyl)imide.

7. The preparation process of a polymer battery according to claim 1, characterized in that, The raw materials of the positive electrode sheet include lithium iron phosphate, polyvinylidene fluoride, and acetylene black, and the mass ratio of the three is 6:2:1.

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