Solid-state sodium-ion battery electrolyte membrane and preparation method

Abstract

The application relates to the field of sodium ion batteries, in particular to a solid-state sodium ion battery electrolyte film and a preparation method, which are used for solving the problems that the existing solid-state electrolyte film has low ion conductivity and poor stability, and the problems that the overall performance of the solid-state sodium ion battery is seriously limited; the molecular structure of the composite polymer is mainly a benzene ring, the benzene ring has good thermal stability and excellent mechanical properties, the introduction of imidazole cations can improve the conductivity of the benzene ring, then the modified polyphenyl ether, the modified doped carbon nitride and polyvinyl alcohol form an interpenetrating network, the carbon nitride as a non-metallic semiconductor material can improve the electrochemical performance of the interpenetrating network, and after being doped with cobalt atoms and boron atoms, the electrochemical performance of the interpenetrating network can be further improved; therefore, the stability and the electrochemical performance of the composite polymer are excellent, and the solid-state sodium ion battery electrolyte film prepared by using the composite polymer as raw material can effectively improve the performance of the solid-state sodium ion battery.

Description

Technical Field

[0001] The present invention relates to the field of sodium ion batteries, and in particular to a solid-state sodium ion battery electrolyte membrane and a preparation method thereof. Background Art

[0002] With the rapid development of electric vehicles, smart grids and other fields, the demand for high energy density, long life and high safety batteries is increasing. As a potential alternative battery, sodium ion batteries have the advantages of abundant resources and low cost. Traditional liquid electrolyte sodium ion batteries have problems such as flammability and leakage, which limit their use in applications with high energy density and high safety requirements. Solid electrolytes are considered to be an important development direction for next-generation battery technology due to their non-flammable and leak-proof properties. However, existing solid electrolyte membranes have problems with low ion conductivity and insufficient stability, which seriously limit the overall performance of solid-state sodium ion batteries.

[0003] Therefore, it is of great practical significance to develop a solid-state sodium ion battery electrolyte membrane with excellent ion conductivity and a preparation method. Summary of the Invention

[0004] In order to overcome the above-mentioned technical problems, the purpose of the present invention is to provide a solid-state sodium ion battery electrolyte membrane and a preparation method, which solves the problems of low ion conductivity and insufficient stability of existing solid-state electrolyte membranes, which seriously limit the overall performance of solid-state sodium ion batteries.

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

[0006] A solid-state sodium ion battery electrolyte membrane comprises the following components in parts by weight:

[0007] 15-35 parts of composite polymer, 20-28 parts of sodium salt and 100-120 parts of solvent;

[0008] Wherein, the composite polymer is prepared by the following steps:

[0009] Step s1: Add polyphenylene ether and chlorobenzene to a three-necked flask equipped with an agitator, a thermometer and a nitrogen gas guide tube, introduce nitrogen protection, stir and react for 15-25 minutes at a temperature of 25-30°C and a stirring rate of 300-400 r / min, then add N-bromosuccinimide and azobisisobutyronitrile and continue stirring and reacting for 20-30 minutes, then raise the temperature to 130-135°C and continue stirring and reacting for 3-5 hours. After the reaction is completed, the reaction product is cooled to room temperature and then added to anhydrous ethanol, allowed to stand and precipitate, and then vacuum filtered. The filter cake is placed in a vacuum drying oven and dried at a temperature of 60-65°C for 1-2 hours to obtain brominated polyphenylene ether;

[0010] Step s2: Add brominated polyphenylene ether, p-hydroxybenzaldehyde, 1,2-dimethylimidazole, anhydrous potassium carbonate and anhydrous tetrahydrofuran to a three-necked flask equipped with a stirrer, a thermometer and a nitrogen gas guide tube, introduce nitrogen protection, stir and react for 30-40 minutes at a temperature of 25-30°C and a stirring rate of 300-400 r / min, then raise the temperature to 55-65°C and continue stirring and reacting for 20-25 hours. After the reaction is completed, cool the reaction product to room temperature, add it to ethyl acetate, let it stand to precipitate, and then vacuum filter. Wash the filter cake with distilled water 3-5 times, then place it in a vacuum drying oven and dry it at a temperature of 50-55°C for 2-3 hours to obtain modified polyphenylene ether;

[0011] Step s3: adding urea, dicyandiamide, cobalt chloride hexahydrate, boron oxide and deionized water to a three-necked flask equipped with a stirrer and a thermometer, stirring and reacting at a temperature of 25-30°C and a stirring rate of 300-400 r / min for 20-25 minutes, then heating to 80-85°C and continuing to stir and react for 6-8 hours. After the reaction is completed, the reaction product is cooled to room temperature, then placed in a vacuum drying oven, dried at a temperature of 60-65°C for 2-3 hours, then ground and placed in a tubular furnace, then calcined at a temperature of 500-520°C for 4-5 hours, and then cooled with the furnace to obtain doped carbon nitride;

[0012] Step s4: adding doped carbon nitride, deionized water and anhydrous ethanol to a three-necked flask equipped with a thermometer, a stirrer and a reflux condenser, stirring and reacting at a temperature of 25-30°C and a stirring rate of 300-400 r / min for 20-25 minutes, then adding silane coupling agent KH-550 and continuing to stir and react for 5-10 minutes, then raising the temperature to reflux and continuing to stir and react for 6-8 hours, after which the reaction product is cooled to room temperature and then centrifuged, and the precipitate is washed with distilled water 3-5 times, and then placed in a vacuum drying oven and dried at a temperature of 45-50°C for 3-4 hours to obtain modified doped carbon nitride;

[0013] Step s5: Add modified polyphenylene ether, modified doped carbon nitride, polyvinyl alcohol and dimethyl sulfoxide to a three-necked flask equipped with a stirrer and a thermometer, and stir the reaction at a temperature of 25-30°C and a stirring rate of 300-400 r / min for 6-8 hours. After the reaction is completed, place the reaction product in a vacuum drying oven and dry it at a temperature of 40-45°C for 4-5 hours to obtain a composite polymer.

[0014] As a further solution of the present invention: the usage ratio of the polyphenylene ether, chlorobenzene, N-bromosuccinimide and azobisisobutyronitrile in step s1 is 10g:100-120mL:17.5-20g:0.9-1.5g; the polyphenylene ether is PPO plastic L543Z.

[0015] As a further solution of the present invention: the usage ratio of the brominated polyphenylene ether, p-hydroxybenzaldehyde, 1,2-dimethylimidazole, anhydrous potassium carbonate and anhydrous tetrahydrofuran in step s2 is 10g:1.8-3.6g:2.1-3.3g:3-5g:120-150mL.

[0016] As a further solution of the present invention: the usage ratio of the urea, dicyandiamide, cobalt chloride hexahydrate, boron oxide and deionized water in step s3 is 5g:5g:0.22-0.36g:0.25-0.35g:110-130mL.

[0017] As a further solution of the present invention: the usage ratio of the doped carbon nitride, deionized water, anhydrous ethanol and silane coupling agent KH-550 in step s4 is 5g:10-12mL:55-60mL:3.2-6.4g.

[0018] As a further solution of the present invention: the usage ratio of the modified polyphenylene ether, modified doped carbon nitride, polyvinyl alcohol and dimethyl sulfoxide in step s5 is 10g:0.2-0.8g:0.5-2.5g:80-100mL; the polyvinyl alcohol is polyvinyl alcohol 1788.

[0019] As a further solution of the present invention: a method for preparing a solid-state sodium ion battery electrolyte membrane comprises the following steps:

[0020] Step 1: Weigh 15-35 parts of the composite polymer, 20-28 parts of the sodium salt, and 100-120 parts of the solvent according to weight and set aside;

[0021] Step 2: Add the composite polymer, sodium salt and solvent into a mixer, stir and mix at a temperature of 50-55° C. and a stirring rate of 300-400 r / min for 1-1.5 hours to obtain an electrolyte membrane slurry;

[0022] Step 3: Pour the electrolyte membrane slurry into a PTFE mold, then place it in a vacuum drying oven, dry it at a temperature of 60-65°C for 10-12 hours, and then cut it into pieces to obtain the solid-state sodium ion battery electrolyte membrane.

[0023] As a further embodiment of the present invention, the sodium salt is one of sodium perchlorate, sodium tetrafluoroborate and sodium hexafluorophosphate.

[0024] As a further embodiment of the present invention: the solvent is one of dimethyl sulfoxide, acetonitrile and N,N-dimethylformamide.

[0025] Beneficial effects of the present invention:

[0026] The present invention discloses a solid-state sodium ion battery electrolyte membrane and a preparation method thereof. The method comprises adding a composite polymer, a sodium salt, and a solvent into a mixer and stirring and mixing them to obtain an electrolyte membrane slurry. The electrolyte membrane slurry is poured into a PTFE mold for drying, and then cut and formed to obtain the solid-state sodium ion battery electrolyte membrane. The main raw material of the solid-state sodium ion battery electrolyte membrane is the composite polymer. The use of the composite polymer can effectively improve the ion conductivity of the electrolyte membrane, so that the electrolyte membrane should have a lower proton transfer resistance, thereby reducing the internal consumption of the solid-state sodium ion battery, improving the energy conversion efficiency, and making the solid-state sodium ion battery have good chemical stability and rechargeability. The solid-state sodium ion battery is widely used in the fields of mobile electronic devices, power tools, electric vehicles, etc.

[0027] In the process of preparing the solid-state sodium ion battery electrolyte membrane, a composite polymer was first prepared. First, polyphenylene ether was brominated with N-bromosuccinimide, and then bromine atoms were introduced into the methyl groups of the polyphenylene ether molecular chain to obtain brominated polyphenylene ether. Then, the brominated polyphenylene ether, p-hydroxybenzaldehyde and 1,2-dimethylimidazole were reacted. The bromine atoms on the brominated polyphenylene ether reacted with the hydroxyl groups on the p-hydroxybenzaldehyde to introduce aldehyde groups into the molecular chain of the polyphenylene ether, and the bromine atoms on the brominated polyphenylene ether reacted with the tertiary amines on the 1,2-dimethylimidazole. The base reacts to form an imidazolium cation, and a quaternary ammonium group is introduced into the molecular chain of polyphenylene ether to obtain a modified polyphenylene ether. Then, urea and dicyanamide are used as raw materials for sintering to form carbon nitride, and cobalt chloride hexahydrate is used as a cobalt source and boron oxide is used as a boron source to dope cobalt atoms and boron atoms into the carbon nitride to obtain doped carbon nitride. Then, the doped carbon nitride is treated with a silane coupling agent KH-550. The silane coupling agent KH-550 is hydrolyzed to form silanol and dehydrated and condensed to the surface of the doped carbon nitride particles. At the same time, amino groups are introduced to obtain a modified doped carbon nitride. The invention discloses a novel nanostructured carbon nitride nanostructured polymer comprising a nanostructured carbon nitride nanostructured polymer and a nanostructured carbon nitride nanostructured polymer. The nanostructured carbon nitride nanostructured polymer comprises ... DETAILED DESCRIPTION

[0028] 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.

[0029] Example 1:

[0030] This embodiment is a method for preparing a solid-state sodium ion battery electrolyte membrane, comprising the following steps:

[0031] Step S1: 10 g of polyphenylene ether and 100 mL of chlorobenzene were added to a three-necked flask equipped with an agitator, a thermometer, and a nitrogen gas guide tube, and nitrogen protection was introduced. The mixture was stirred at a temperature of 25 ° C and a stirring rate of 300 r / min for 15 minutes. Then, 17.5 g of N-bromosuccinimide and 0.9 g of azobisisobutyronitrile were added and the stirring reaction was continued for 20 minutes. After that, the temperature was raised to 130 ° C and the stirring reaction was continued for 3 hours. After the reaction was completed, the reaction product was cooled to room temperature and then added to anhydrous ethanol. The precipitate was allowed to stand and then vacuum filtered. The filter cake was placed in a vacuum drying oven and dried at a temperature of 60 ° C for 1 hour to obtain brominated polyphenylene ether;

[0032] Step S2: 10 g of brominated polyphenylene ether, 1.8 g of p-hydroxybenzaldehyde, 2.1 g of 1,2-dimethylimidazole, 3 g of anhydrous potassium carbonate and 120 mL of anhydrous tetrahydrofuran were added to a three-necked flask equipped with a stirrer, a thermometer and a nitrogen gas guide tube, and nitrogen protection was introduced. The mixture was stirred at a temperature of 25° C. and a stirring rate of 300 r / min for 30 minutes, and then the temperature was raised to 55° C. and the stirring reaction was continued for 20 hours. After the reaction was completed, the reaction product was cooled to room temperature and then added to ethyl acetate. The mixture was allowed to stand for precipitation, and then vacuum filtered. The filter cake was washed with distilled water three times, and then placed in a vacuum drying oven and dried at a temperature of 50° C. for 2 hours to obtain a modified polyphenylene ether;

[0033] Step S3: 5 g of urea, 5 g of dicyandiamide, 0.22 g of cobalt chloride hexahydrate, 0.25 g of boron oxide and 110 mL of deionized water were added to a three-necked flask equipped with a stirrer and a thermometer, and the mixture was stirred at 25 ° C. and a stirring rate of 300 r / min for 20 min. The mixture was then heated to 80 ° C. and the stirring reaction was continued for 6 h. After the reaction was completed, the reaction product was cooled to room temperature, placed in a vacuum drying oven, dried at 60 ° C. for 2 h, ground and placed in a tubular furnace, and then calcined at 500 ° C. for 4 h. The mixture was then cooled with the furnace to obtain doped carbon nitride;

[0034] Step S4: 5 g of doped carbon nitride, 10 mL of deionized water, and 55 mL of anhydrous ethanol were added to a three-necked flask equipped with a thermometer, a stirrer, and a reflux condenser, and stirred for reaction at a temperature of 25 ° C. and a stirring rate of 300 r / min for 20 minutes. Then, 3.2 g of silane coupling agent KH-550 was added and the stirring reaction was continued for 5 minutes. Then, the temperature was raised to reflux and the stirring reaction was continued for 6 hours. After the reaction was completed, the reaction product was cooled to room temperature and then centrifuged. The precipitate was washed with distilled water 3 times and then placed in a vacuum drying oven and dried at a temperature of 45 ° C. for 3 hours to obtain modified doped carbon nitride;

[0035] Step S5: 10 g of modified polyphenyl ether, 0.2 g of modified carbon nitride doped, 0.5 g of polyvinyl alcohol, and 80 mL of dimethyl sulfoxide were added to a three-necked flask equipped with a stirrer and a thermometer, and stirred at a temperature of 25℃ and a stirring rate of 300 r / min for 6 h. After the reaction was completed, the reaction product was placed in a vacuum drying oven and dried at a temperature of 40℃ for 4 h to obtain a composite polymer;

[0036] Step S6: The composite polymer 15 parts, sodium salt 20 parts, and solvent 100 parts were weighed according to the weight parts, and were prepared for use. The sodium salt is sodium perchlorate, and the solvent is dimethyl sulfoxide;

[0037] Step S7: The composite polymer, sodium salt, and solvent were added to a mixer and stirred and mixed at a temperature of 50℃ and a stirring rate of 300 r / min for 1 h to obtain an electrolyte membrane slurry;

[0038] Step S8: The electrolyte membrane slurry was poured into a PTFE mold, and then placed in a vacuum drying oven and dried at a temperature of 60℃ for 10 h, and then cut into shape to obtain the solid-state sodium ion battery electrolyte membrane.

[0039] Example 2:

[0040] The present embodiment is a preparation method of a solid-state sodium ion battery electrolyte membrane, comprising the following steps:

[0041] Step S1: 10 g of polyphenyl ether and 110 mL of chlorobenzene were added to a three-necked flask equipped with a stirrer, a thermometer, and a nitrogen gas inlet tube, and protected by nitrogen. The mixture was stirred at a temperature of 28℃ and a stirring rate of 350 r / min for 20 min, and then 18.5 g of N-bromosuccinimide and 1.2 g of azobisisobutyronitrile were added and the reaction was continued for 25 min. The temperature was then increased to 132℃ and the reaction was continued for 4 h. After the reaction was completed, the reaction product was cooled to room temperature, and then added to anhydrous ethanol. The precipitate was separated by vacuum filtration, and the filter cake was placed in a vacuum drying oven and dried at a temperature of 62℃ for 1.5 h to obtain brominated polyphenyl ether;

[0042] Step S2: 10 g of brominated polyphenyl ether, 2.4 g of p-hydroxybenzaldehyde, 2.7 g of 1,2-dimethylimidazole, 4 g of anhydrous potassium carbonate, and 135 mL of anhydrous tetrahydrofuran were added to a three-necked flask equipped with a stirrer, a thermometer, and a nitrogen inlet tube, and protected by nitrogen. The reaction was stirred at a temperature of 28°C and a stirring rate of 350 r / min for 35 min, and then the temperature was raised to 60°C and the reaction was continued for 22 h. After the reaction was completed, the reaction product was cooled to room temperature, and then added to ethyl acetate. The precipitate was separated by standing, and then vacuum filtered. The filter cake was washed with distilled water four times, and then placed in a vacuum drying oven and dried at a temperature of 52°C for 2.5 h to obtain the modified polyphenyl ether;

[0043] Step S3: 5 g of urea, 5 g of dicyanamide, 0.29 g of cobalt chloride hexahydrate, 0.3 g of boron oxide, and 120 mL of deionized water were added to a three-necked flask equipped with a stirrer and a thermometer. The reaction was stirred at a temperature of 28°C and a stirring rate of 350 r / min for 22 min, and then the temperature was raised to 82°C and the reaction was continued for 7 h. After the reaction was completed, the reaction product was cooled to room temperature, and then placed in a vacuum drying oven and dried at a temperature of 62°C for 2.5 h. After grinding, it was placed in a tube furnace, and then calcined at a temperature of 510°C for 4.5 h. After cooling in the furnace, the doped carbon nitride was obtained;

[0044] Step S4: 5 g of the doped carbon nitride, 11 mL of deionized water, and 58 mL of anhydrous ethanol were added to a three-necked flask equipped with a thermometer, a stirrer, and a reflux condenser. The reaction was stirred at a temperature of 28°C and a stirring rate of 350 r / min for 22 min, and then 4.8 g of silane coupling agent KH-550 was added and the reaction was continued for 8 min. The temperature was then raised to reflux and the reaction was continued for 7 h. After the reaction was completed, the reaction product was cooled to room temperature, and then centrifuged. The precipitate was washed with distilled water four times, and then placed in a vacuum drying oven and dried at a temperature of 48°C for 3.5 h to obtain the modified doped carbon nitride;

[0045] Step S5: 10 g of the modified polyphenyl ether, 0.5 g of the modified doped carbon nitride, 1.5 g of polyvinyl alcohol, and 90 mL of dimethyl sulfoxide were added to a three-necked flask equipped with a stirrer and a thermometer. The reaction was stirred at a temperature of 28°C and a stirring rate of 350 r / min for 7 h. After the reaction was completed, the reaction product was placed in a vacuum drying oven and dried at a temperature of 42°C for 4.5 h to obtain the composite polymer;

[0046] Step S6: The composite polymer was weighed at 25 parts, the sodium salt was weighed at 24 parts, and the solvent was weighed at 110 parts, and was prepared for use. The sodium salt was sodium tetrafluoroborate, and the solvent was acetonitrile;

[0047] Step S7: adding the composite polymer, sodium salt and solvent into a mixer, stirring and mixing at a temperature of 52° C. and a stirring rate of 350 r / min for 1.2 h to obtain an electrolyte membrane slurry;

[0048] Step S8: pouring the electrolyte membrane slurry into a PTFE mold, then placing it in a vacuum drying oven, drying it at a temperature of 62° C. for 11 hours, and then cutting and shaping it to obtain the solid-state sodium ion battery electrolyte membrane.

[0049] Example 3:

[0050] This embodiment is a method for preparing a solid-state sodium ion battery electrolyte membrane, comprising the following steps:

[0051] Step S1: 10 g of polyphenylene ether and 120 mL of chlorobenzene were added to a three-necked flask equipped with an agitator, a thermometer, and a nitrogen gas guide tube, and nitrogen protection was introduced. The mixture was stirred at a temperature of 30° C. and a stirring rate of 400 r / min for 25 minutes. Subsequently, 20 g of N-bromosuccinimide and 1.5 g of azobisisobutyronitrile were added and the stirring reaction was continued for 30 minutes. The mixture was then heated to 135° C. and the stirring reaction was continued for 5 hours. After the reaction was completed, the reaction product was cooled to room temperature and then added to anhydrous ethanol. The mixture was allowed to stand for precipitation, and then vacuum filtered. The filter cake was placed in a vacuum drying oven and dried at a temperature of 65° C. for 2 hours to obtain brominated polyphenylene ether;

[0052] Step S2: 10 g of brominated polyphenylene ether, 3.6 g of p-hydroxybenzaldehyde, 3.3 g of 1,2-dimethylimidazole, 5 g of anhydrous potassium carbonate and 150 mL of anhydrous tetrahydrofuran were added to a three-necked flask equipped with a stirrer, a thermometer and a nitrogen gas guide tube, and nitrogen protection was introduced. The mixture was stirred at a temperature of 30° C. and a stirring rate of 400 r / min for 40 minutes, and then the temperature was raised to 65° C. and the stirring reaction was continued for 25 hours. After the reaction was completed, the reaction product was cooled to room temperature and then added to ethyl acetate. The precipitate was allowed to stand and then vacuum filtered. The filter cake was washed with distilled water 5 times and then placed in a vacuum drying oven and dried at a temperature of 55° C. for 3 hours to obtain a modified polyphenylene ether;

[0053] Step S3: 5 g of urea, 5 g of dicyandiamide, 0.36 g of cobalt chloride hexahydrate, 0.35 g of boron oxide and 130 mL of deionized water were added to a three-necked flask equipped with a stirrer and a thermometer, and the mixture was stirred at 30 ° C. and a stirring rate of 400 r / min for 25 minutes. The mixture was then heated to 85 ° C. and stirred for 8 hours. After the reaction, the reaction product was cooled to room temperature, placed in a vacuum drying oven, dried at 65 ° C. for 3 hours, ground, and placed in a tubular furnace. It was then calcined at 520 ° C. for 5 hours and then cooled with the furnace to obtain doped carbon nitride;

[0054] Step S4: 5 g of doped carbon nitride, 12 mL of deionized water, and 60 mL of anhydrous ethanol were added to a three-necked flask equipped with a thermometer, a stirrer, and a reflux condenser, and stirred for 25 minutes at a temperature of 30° C. and a stirring rate of 400 r / min. Then, 6.4 g of silane coupling agent KH-550 was added and the stirring reaction was continued for 10 minutes. Then, the temperature was raised to reflux and the stirring reaction was continued for 8 hours. After the reaction was completed, the reaction product was cooled to room temperature and then centrifuged. The precipitate was washed with distilled water 5 times and then placed in a vacuum drying oven and dried at a temperature of 50° C. for 4 hours to obtain modified doped carbon nitride;

[0055] Step S5: adding 10 g of modified polyphenylene ether, 0.8 g of modified doped carbon nitride, 2.5 g of polyvinyl alcohol, and 100 mL of dimethyl sulfoxide to a three-necked flask equipped with a stirrer and a thermometer, stirring the mixture at 30° C. and a stirring rate of 400 r / min for 8 h. After the reaction is completed, the reaction product is placed in a vacuum drying oven and dried at 45° C. for 5 h to obtain a composite polymer;

[0056] Step S6: Weigh 35 parts of the composite polymer, 28 parts of the sodium salt, and 120 parts of the solvent according to weight, and set aside; the sodium salt is sodium hexafluorophosphate; and the solvent is N,N-dimethylformamide;

[0057] Step S7: adding the composite polymer, sodium salt and solvent into a mixer, stirring and mixing at a temperature of 55° C. and a stirring rate of 400 r / min for 1.5 hours to obtain an electrolyte membrane slurry;

[0058] Step S8: pouring the electrolyte membrane slurry into a PTFE mold, then placing it in a vacuum drying oven, drying it at a temperature of 65° C. for 12 hours, and then cutting and shaping it to obtain the solid-state sodium ion battery electrolyte membrane.

[0059] Comparative Example 1:

[0060] This comparative example is a method for preparing a solid-state sodium ion battery electrolyte membrane, comprising the following steps:

[0061] Step S1: 10 g of polyphenylene ether, 2.5 g of polyvinyl alcohol, and 100 mL of dimethyl sulfoxide were added to a three-necked flask equipped with a stirrer and a thermometer, and stirred at 30° C. and a stirring rate of 400 r / min for 8 h. After the reaction, the reaction product was placed in a vacuum drying oven and dried at 45° C. for 5 h to obtain a composite polymer;

[0062] Step S2: Weigh 35 parts of the composite polymer, 28 parts of the sodium salt, and 120 parts of the solvent according to weight, and set aside; the sodium salt is sodium hexafluorophosphate; and the solvent is N,N-dimethylformamide;

[0063] Step S3: adding the composite polymer, sodium salt and solvent into a mixer, stirring and mixing at a temperature of 55° C. and a stirring rate of 400 r / min for 1.5 hours to obtain an electrolyte membrane slurry;

[0064] Step S4: pouring the electrolyte membrane slurry into a PTFE mold, then placing it in a vacuum drying oven, drying it at a temperature of 65° C. for 12 hours, and then cutting and shaping it to obtain the solid-state sodium ion battery electrolyte membrane.

[0065] Comparative Example 2:

[0066] This comparative example is a method for preparing a solid-state sodium ion battery electrolyte membrane, comprising the following steps:

[0067] Step S1: 10 g of polyphenylene ether and 120 mL of chlorobenzene were added to a three-necked flask equipped with an agitator, a thermometer, and a nitrogen gas guide tube, and nitrogen protection was introduced. The mixture was stirred at a temperature of 30° C. and a stirring rate of 400 r / min for 25 minutes. Subsequently, 20 g of N-bromosuccinimide and 1.5 g of azobisisobutyronitrile were added and the stirring reaction was continued for 30 minutes. The mixture was then heated to 135° C. and the stirring reaction was continued for 5 hours. After the reaction was completed, the reaction product was cooled to room temperature and then added to anhydrous ethanol. The mixture was allowed to stand for precipitation, and then vacuum filtered. The filter cake was placed in a vacuum drying oven and dried at a temperature of 65° C. for 2 hours to obtain brominated polyphenylene ether;

[0068] Step S2: 10 g of brominated polyphenylene ether, 3.6 g of p-hydroxybenzaldehyde, 3.3 g of 1,2-dimethylimidazole, 5 g of anhydrous potassium carbonate and 150 mL of anhydrous tetrahydrofuran were added to a three-necked flask equipped with a stirrer, a thermometer and a nitrogen gas guide tube, and nitrogen protection was introduced. The mixture was stirred at a temperature of 30° C. and a stirring rate of 400 r / min for 40 minutes, and then the temperature was raised to 65° C. and the stirring reaction was continued for 25 hours. After the reaction was completed, the reaction product was cooled to room temperature and then added to ethyl acetate. The precipitate was allowed to stand and then vacuum filtered. The filter cake was washed with distilled water 5 times and then placed in a vacuum drying oven and dried at a temperature of 55° C. for 3 hours to obtain a modified polyphenylene ether;

[0069] Step S3: 10 g of modified polyphenylene ether, 2.5 g of polyvinyl alcohol, and 100 mL of dimethyl sulfoxide were added to a three-necked flask equipped with a stirrer and a thermometer, and the mixture was stirred at 30° C. and a stirring rate of 400 r / min for 8 h. After the reaction, the reaction product was placed in a vacuum drying oven and dried at 45° C. for 5 h to obtain a composite polymer;

[0070] Step S4: Weigh 35 parts of the composite polymer, 28 parts of the sodium salt, and 120 parts of the solvent according to weight, and set aside; the sodium salt is sodium hexafluorophosphate; and the solvent is N,N-dimethylformamide;

[0071] Step S5: adding the composite polymer, sodium salt and solvent into a mixer, stirring and mixing at a temperature of 55° C. and a stirring rate of 400 r / min for 1.5 hours to obtain an electrolyte membrane slurry;

[0072] Step S6: pouring the electrolyte membrane slurry into a PTFE mold, then placing it in a vacuum drying oven, drying it at a temperature of 65° C. for 12 hours, and then cutting and shaping it to obtain the solid-state sodium ion battery electrolyte membrane.

[0073] Comparative Example 3:

[0074] This comparative example is a method for preparing a solid-state sodium ion battery electrolyte membrane, comprising the following steps:

[0075] Step S1: 5 g of urea, 5 g of dicyandiamide, 0.36 g of cobalt chloride hexahydrate, 0.35 g of boron oxide and 130 mL of deionized water were added to a three-necked flask equipped with a stirrer and a thermometer, and stirred at 30 ° C. and a stirring rate of 400 r / min for 25 minutes, then heated to 85 ° C. and continued to stir for 8 hours. After the reaction, the reaction product was cooled to room temperature, then placed in a vacuum drying oven, dried at 65 ° C. for 3 hours, then ground and placed in a tube furnace, and then calcined at 520 ° C. for 5 hours, and then cooled with the furnace to obtain doped carbon nitride;

[0076] Step S2: 5 g of doped carbon nitride, 12 mL of deionized water, and 60 mL of anhydrous ethanol were added to a three-necked flask equipped with a thermometer, a stirrer, and a reflux condenser, and stirred for 25 minutes at a temperature of 30° C. and a stirring rate of 400 r / min. Then, 6.4 g of silane coupling agent KH-550 was added and the stirring reaction was continued for 10 minutes. Then, the temperature was raised to reflux and the stirring reaction was continued for 8 hours. After the reaction was completed, the reaction product was cooled to room temperature and then centrifuged. The precipitate was washed with distilled water 5 times and then placed in a vacuum drying oven and dried at a temperature of 50° C. for 4 hours to obtain modified doped carbon nitride;

[0077] Step S3: 0.8 g of modified doped carbon nitride, 2.5 g of polyvinyl alcohol, and 100 mL of dimethyl sulfoxide were added to a three-necked flask equipped with a stirrer and a thermometer, and the mixture was stirred at 30° C. and a stirring rate of 400 r / min for 8 h. After the reaction, the reaction product was placed in a vacuum drying oven and dried at 45° C. for 5 h to obtain a composite polymer;

[0078] Step S4: Weigh 35 parts of the composite polymer, 28 parts of the sodium salt, and 120 parts of the solvent according to weight, and set aside; the sodium salt is sodium hexafluorophosphate; and the solvent is N,N-dimethylformamide;

[0079] Step S5: adding the composite polymer, sodium salt and solvent into a mixer, stirring and mixing at a temperature of 55° C. and a stirring rate of 400 r / min for 1.5 h to obtain an electrolyte membrane slurry;

[0080] Step S6: pouring the electrolyte membrane slurry into a PTFE mold, then placing it in a vacuum drying oven, drying it at a temperature of 65° C. for 12 hours, and then cutting and shaping it to obtain the solid-state sodium ion battery electrolyte membrane.

[0081] Comparative Example 4:

[0082] This comparative example is a method for preparing a solid-state sodium ion battery electrolyte membrane, comprising the following steps:

[0083] Step S1: 5 g of urea, 5 g of dicyandiamide, 0.36 g of cobalt chloride hexahydrate, 0.35 g of boron oxide and 130 mL of deionized water were added to a three-necked flask equipped with a stirrer and a thermometer, and stirred at 30 ° C. and a stirring rate of 400 r / min for 25 minutes, then heated to 85 ° C. and continued to stir for 8 hours. After the reaction, the reaction product was cooled to room temperature, then placed in a vacuum drying oven, dried at 65 ° C. for 3 hours, then ground and placed in a tube furnace, and then calcined at 520 ° C. for 5 hours, and then cooled with the furnace to obtain doped carbon nitride;

[0084] Step S2: 5 g of doped carbon nitride, 12 mL of deionized water, and 60 mL of anhydrous ethanol were added to a three-necked flask equipped with a thermometer, a stirrer, and a reflux condenser, and stirred for 25 minutes at a temperature of 30° C. and a stirring rate of 400 r / min. Then, 6.4 g of silane coupling agent KH-550 was added and the stirring reaction was continued for 10 minutes. Then, the temperature was raised to reflux and the stirring reaction was continued for 8 hours. After the reaction was completed, the reaction product was cooled to room temperature and then centrifuged. The precipitate was washed with distilled water 5 times and then placed in a vacuum drying oven and dried at a temperature of 50° C. for 4 hours to obtain modified doped carbon nitride;

[0085] Step S3: 10 g of polyphenylene ether, 0.8 g of modified doped carbon nitride, 2.5 g of polyvinyl alcohol, and 100 mL of dimethyl sulfoxide were added to a three-necked flask equipped with a stirrer and a thermometer, and stirred at a temperature of 30° C. and a stirring rate of 400 r / min for 8 h. After the reaction, the reaction product was placed in a vacuum drying oven and dried at a temperature of 45° C. for 5 h to obtain a composite polymer;

[0086] Step S4: Weigh 35 parts of the composite polymer, 28 parts of the sodium salt, and 120 parts of the solvent according to weight, and set aside; the sodium salt is sodium hexafluorophosphate; and the solvent is N,N-dimethylformamide;

[0087] Step S5: adding the composite polymer, sodium salt and solvent into a mixer, stirring and mixing at a temperature of 55° C. and a stirring rate of 400 r / min for 1.5 hours to obtain an electrolyte membrane slurry;

[0088] Step S6: pouring the electrolyte membrane slurry into a PTFE mold, then placing it in a vacuum drying oven, drying it at a temperature of 65° C. for 12 hours, and then cutting and shaping it to obtain the solid-state sodium ion battery electrolyte membrane.

[0089] The solid-state sodium ion battery electrolyte membranes of Examples 1-3 and Comparative Examples 1-4 were used as separators, sodium iron phosphate was used as the positive electrode, and metallic sodium was used as the negative electrode to assemble CR2032 button cells. The performance of the CR2032 button cells was tested, and the test results are shown below:

[0090]

[0091] Referring to the data in the above table, according to the comparison between Examples 1-3 and Comparative Examples 1-4, it can be seen that the electrochemical performance of the solid-state sodium ion battery electrolyte membrane of the present invention is excellent. When there is no modified doped carbon nitride and modified polyphenylene ether, its electrochemical performance is greatly reduced.

[0092] Throughout this 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.

[0093] 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 solid-state sodium ion battery electrolyte membrane, characterized in that It comprises the following components in parts by weight: 15-35 parts of composite polymer, 20-28 parts of sodium salt and 100-120 parts of solvent; Wherein, the composite polymer is prepared by the following steps: Step s1: polyphenylene ether and chlorobenzene are stirred for reaction, and then N-bromosuccinimide and azobisisobutyronitrile are added and the reaction is continued with stirring. After the reaction is completed, the reaction product is cooled and then added to anhydrous ethanol. The product is allowed to stand for precipitation, and then vacuum filtered and the filter cake is dried to obtain brominated polyphenylene ether; Step s2: stirring and reacting brominated polyphenylene ether, p-hydroxybenzaldehyde, 1,2-dimethylimidazole, anhydrous potassium carbonate, and anhydrous tetrahydrofuran. After the reaction, the reaction product is cooled and then added to ethyl acetate. The product is allowed to stand to precipitate, and then vacuum filtered. The filter cake is washed and dried to obtain a modified polyphenylene ether. Step s3: stirring urea, dicyandiamide, cobalt chloride hexahydrate, boron oxide and deionized water to react, cooling the reaction product after the reaction is completed, then drying, grinding, calcining, and then cooling in the furnace to obtain doped carbon nitride; Step s4: stirring the doped carbon nitride, deionized water, and anhydrous ethanol to react, then adding the silane coupling agent KH-550 and continuing the stirring reaction. After the reaction is completed, the reaction product is cooled, then centrifuged, and the precipitate is washed and dried to obtain the modified doped carbon nitride; Step s5: stirring the modified polyphenylene ether, modified doped carbon nitride, polyvinyl alcohol and dimethyl sulfoxide to react, and drying the reaction product after the reaction is completed to obtain a composite polymer.

2. A solid-state sodium ion battery electrolyte membrane according to claim 1, characterized in that: The usage ratio of the polyphenylene ether, chlorobenzene, N-bromosuccinimide and azobisisobutyronitrile in step s1 is 10g:100-120mL:17.5-20g:0.9-1.5g; the polyphenylene ether is PPO plastic L543Z.

3. A solid-state sodium ion battery electrolyte membrane according to claim 1, characterized in that: The usage ratio of the brominated polyphenylene ether, p-hydroxybenzaldehyde, 1,2-dimethylimidazole, anhydrous potassium carbonate and anhydrous tetrahydrofuran in step s2 is 10 g: 1.8-3.6 g: 2.1-3.3 g: 3-5 g: 120-150 mL.

4. A solid-state sodium ion battery electrolyte membrane according to claim 1, characterized in that: The usage ratio of the urea, dicyandiamide, cobalt chloride hexahydrate, boron oxide and deionized water in step s3 is 5g:5g:0.22-0.36g:0.25-0.35g:110-130mL.

5. A solid-state sodium ion battery electrolyte membrane according to claim 1, characterized in that: The usage ratio of the doped carbon nitride, deionized water, anhydrous ethanol and silane coupling agent KH-550 in step s4 is 5g:10-12mL:55-60mL:3.2-6.4g.

6. A solid-state sodium ion battery electrolyte membrane according to claim 1, characterized in that: The usage ratio of the modified polyphenylene ether, modified doped carbon nitride, polyvinyl alcohol and dimethyl sulfoxide in step s5 is 10g:0.2-0.8g:0.5-2.5g:80-100mL; the polyvinyl alcohol is polyvinyl alcohol 1788.

7. A method for preparing a solid-state sodium ion battery electrolyte membrane according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: Weigh 15-35 parts of the composite polymer, 20-28 parts of the sodium salt, and 100-120 parts of the solvent according to weight and set aside; Step 2: Add the composite polymer, sodium salt and solvent into a mixer, stir and mix at a temperature of 50-55° C. and a stirring rate of 300-400 r / min for 1-1.5 hours to obtain an electrolyte membrane slurry; Step 3: Pour the electrolyte membrane slurry into a PTFE mold, then place it in a vacuum drying oven, dry it at a temperature of 60-65°C for 10-12 hours, and then cut it into pieces to obtain the solid-state sodium ion battery electrolyte membrane.

8. The method for preparing a solid-state sodium ion battery electrolyte membrane according to claim 7, characterized in that: The sodium salt is one of sodium perchlorate, sodium tetrafluoroborate and sodium hexafluorophosphate.

9. The method for preparing a solid-state sodium ion battery electrolyte membrane according to claim 7, characterized in that: The solvent is one of dimethyl sulfoxide, acetonitrile and N,N-dimethylformamide.

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