A composite polymer electrolyte for solid-state sodium ion batteries

Abstract

The present invention relates to the field of sodium ion batteries, and in particular to a composite polymer electrolyte for solid-state sodium ion batteries, which is used to solve the problem of low ionic conductivity of existing polymer electrolytes. The electrolyte is prepared using a modified polymer and modified graphene oxide as main raw materials. The modified polymer contains a large amount of imidazolium cations, which effectively improves the ionic conductivity of the polymer electrolyte. Adding modified graphene thereto can further improve its electrochemical activity and mechanical properties, thereby enhancing the ionic conductivity and mechanical stability of the composite polymer electrolyte. Therefore, under the synergistic effect of the modified polymer and modified graphene oxide, the prepared electrolyte has excellent ionic conductivity, which is conducive to the rapid transmission of sodium ions, thereby improving the charge and discharge performance of the sodium ion battery. In addition, the electrolyte has excellent stability, which improves the safety and reliability of the sodium ion battery.

Description

Technical Field

[0001] The present invention relates to the field of sodium ion batteries, and in particular to a composite polymer electrolyte for solid-state sodium ion batteries. Background Art

[0002] With the continuous development of new energy technologies, sodium-ion batteries (SIBs) have attracted widespread attention as a potential high-performance, low-cost, and environmentally friendly energy storage technology. However, traditional liquid electrolytes have problems such as leakage, volatility, and poor safety. Solid-state electrolytes, however, have become a research hotspot due to their advantages such as high safety and long life. With the popularization of electronic devices such as electric vehicles and smartphones, the demand for high-performance and high-safety batteries is increasing. However, the ionic conductivity of polymer electrolytes is generally low, which limits their application in SIBs.

[0003] Therefore, it is of great significance to develop a high-performance composite polymer electrolyte for solid-state sodium ion batteries. Summary of the Invention

[0004] In order to overcome the above technical problems, the purpose of the present invention is to provide a composite polymer electrolyte for solid-state sodium ion batteries, which solves the problem that the ionic conductivity of existing polymer electrolytes is generally low, which limits their application in sodium ion batteries.

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

[0006] A composite polymer electrolyte for a solid-state sodium ion battery, comprising the following components in parts by weight:

[0007] 10-16 parts of modified polymer, 0.15-1.5 parts of modified graphene oxide, 2-4 parts of sodium perchlorate and 60-80 parts of anhydrous acetonitrile;

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

[0009] Step a1: Diethylene glycol, triethylamine, 4-dimethylaminopyridine and toluene are added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen is introduced for protection. The mixture is stirred at a temperature of -10-0°C and a stirring rate of 400-500 r / min for 10-15 minutes. Then, acryloyl chloride solution is added dropwise while stirring at a dropping rate of 1-2 drops / s. After the addition is complete, the temperature is raised to 25-30°C and the stirring reaction is continued for 10-15 hours. After the reaction is completed, the reaction product is vacuum filtered, and the filtrate is washed with saturated brine and distilled water 2-3 times in sequence, and then extracted with dichloromethane 2-3 times. The extracts are combined and the extracts are rotary evaporated to remove the solvent to obtain intermediate product I;

[0010] Step a2: Add intermediate product I, triethylamine, 4-dimethylaminopyridine and dichloromethane to a three-necked flask equipped with a stirrer, a thermometer, a gas guide tube and a constant pressure dropping funnel, introduce nitrogen protection, and stir the reaction at a temperature of -10-0°C and a stirring rate of 400-500 r / min for 10-15 minutes. Then, add phosphorus oxychloride solution dropwise while stirring, and control the dropping rate to 1-2 drops / s. After the addition is complete, the temperature is raised to 25-30°C and the stirring reaction is continued for 10-15 hours. After the reaction is completed, the reaction product is vacuum filtered, and the filtrate is washed 2-3 times with saturated sodium bicarbonate solution and distilled water in sequence, and then dried over anhydrous sodium sulfate. After vacuum filtration, the filtrate is rotary evaporated to remove the solvent to obtain intermediate product II;

[0011] Step a3: epichlorohydrin and deionized water are added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen protection is introduced. The reaction is stirred at a temperature of 25-30 ° C and a stirring rate of 400-500 r / min for 10-15 minutes. Then, vinyl imidazole is added dropwise while stirring at a temperature of 60-65 ° C. The dropwise addition rate is controlled to 1-2 drops / s. After the addition is completed, the stirring reaction is continued for 3-5 hours. After the reaction is completed, the reaction product is rotary evaporated to remove the solvent, and then washed with ethyl acetate 2-3 times. Then, it is placed in a vacuum drying oven and dried at a temperature of 40-45 ° C for 6-8 hours to obtain intermediate product III;

[0012] Step a4: Add intermediate product II, intermediate product III, azobisisobutyronitrile and anhydrous ethanol to a three-necked flask equipped with a stirrer, a thermometer, a gas guide tube and a reflux condenser, introduce nitrogen protection, and stir the reaction at a temperature of 25-30°C and a stirring rate of 400-500 r / min for 10-15 minutes, then raise the temperature to reflux and stir the reaction for 5-6 hours. After the reaction is completed, the reaction product is cooled to room temperature, then washed with anhydrous ether 2-3 times, and then rotary evaporated to remove the solvent to obtain a modified polymer.

[0013] As a further embodiment of the present invention: the usage ratio of the diethylene glycol, triethylamine, 4-dimethylaminopyridine, toluene and acryloyl chloride solution in step a1 is 0.12-0.15 mol: 0.1 mol: 0.18-0.22 g: 40-45 mL: 30 mL.

[0014] As a further solution of the present invention: the acryloyl chloride solution in step a1 is a solution formed by dissolving acryloyl chloride in toluene at a ratio of 0.1 mol: 28-30 mL.

[0015] As a further embodiment of the present invention: the usage ratio of the intermediate product I, triethylamine, 4-dimethylaminopyridine, dichloromethane and phosphorus oxychloride solution in step a2 is 0.1 mol: 0.12-0.15 mol: 0.22-0.28 g: 80-100 mL: 30-35 mL.

[0016] As a further solution of the present invention: the phosphorus oxychloride solution in step a2 is a solution formed by dissolving phosphorus oxychloride in dichloromethane at a ratio of 0.1-0.11 mol:28-30 mL.

[0017] As a further solution of the present invention: the usage ratio of the epichlorohydrin, deionized water and vinyl imidazole in step a3 is 0.1 mol:50-55 mL:0.1 mol.

[0018] As a further solution of the present invention: the usage ratio of the intermediate product II, intermediate product III, azobisisobutyronitrile and anhydrous ethanol in step a4 is 0.1 mol: 0.1-0.4 mol: 0.15-0.35 g: 100-120 mL.

[0019] As a further solution of the present invention: the modified graphene oxide is prepared by the following steps:

[0020] Step b1: adding graphite powder, concentrated sulfuric acid and concentrated nitric acid to a three-necked flask equipped with a stirrer and a thermometer, stirring and reacting for 20-30 minutes at a temperature of -5-0°C and a stirring rate of 400-500 r / min, then adding potassium permanganate and continuing to stir and react for 1-2 hours, then heating to 50-55°C and continuing to stir and react for 10-15 hours, pouring the reaction product into hydrogen peroxide after the reaction is completed, and then centrifuging. The precipitate is washed with hydrochloric acid solution and distilled water for 3-5 times in sequence, and then placed in a vacuum drying oven and dried at a temperature of 60-70°C for 2-3 hours to obtain graphene oxide;

[0021] Step b2: Add graphene oxide, silane coupling agent KH-550 and ethanol solution to a three-necked flask equipped with a stirrer, a thermometer and a reflux condenser, stir and react for 20-30 minutes at a temperature of 25-30°C and a stirring rate of 400-500r / min, then raise the temperature to reflux and continue stirring and reacting for 5-6 hours. After the reaction is completed, the reaction product is cooled to room temperature and then centrifuged. The precipitate is placed in a vacuum drying oven and dried at a temperature of 50-55°C for 2-3 hours to obtain modified graphene oxide.

[0022] As a further solution of the present invention: the usage ratio of the graphite powder, concentrated sulfuric acid, concentrated nitric acid and potassium permanganate in step b1 is 1 g:30-35 mL:10-12 mL:12-16 g.

[0023] As a further solution of the present invention: in step b1, the mass fraction of the concentrated sulfuric acid is 96-98%, the mass fraction of the concentrated nitric acid is 67-68%, the mass fraction of the hydrogen peroxide is 18-22%, and the mass fraction of the hydrochloric acid solution is 8-10%.

[0024] As a further solution of the present invention: the usage ratio of the graphene oxide, the silane coupling agent KH-550 and the ethanol solution in step b2 is 1 g: 2-8 mL: 30-40 mL.

[0025] As a further solution of the present invention: the volume fraction of the ethanol solution in step b2 is 80-85%.

[0026] As a further solution of the present invention: the composite polymer electrolyte is prepared by the following steps:

[0027] Step 1: Weigh 10-16 parts of modified polymer, 0.15-1.5 parts of modified graphene oxide, 2-4 parts of sodium perchlorate and 60-80 parts of anhydrous acetonitrile according to weight parts and set aside;

[0028] Step 2: The modified polymer, modified graphene oxide, sodium perchlorate and anhydrous acetonitrile are mixed evenly at a temperature of 25-30°C and a stirring rate of 400-500r / min, then poured into a PTFE mold, and then allowed to stand for 20-30 hours. Then, the mold is placed in a vacuum drying oven and dried at a temperature of 60-65°C for 3-5 hours. The mold is then cut into pieces to obtain a composite polymer electrolyte for solid-state sodium ion batteries.

[0029] Beneficial effects of the present invention:

[0030] The present invention discloses a composite polymer electrolyte for solid-state sodium ion batteries. The composite polymer electrolyte is prepared by uniformly mixing a modified polymer, modified graphene oxide, sodium perchlorate and anhydrous acetonitrile, pouring the mixture into a PTFE mold, allowing the mixture to stand and dry, and then cutting and shaping the mixture to obtain a composite polymer electrolyte for solid-state sodium ion batteries. The electrolyte is prepared using the modified polymer and modified graphene oxide as main raw materials. The modified polymer contains a large amount of imidazolium cations. The imidazolium cations have good ionic conductivity and thermal stability, can form effective ion transport channels in the polymer matrix, promote the rapid migration of sodium ions, and effectively improve the ionic conductivity of the polymer electrolyte. At the same time, the imidazolium cation additive can also improve the polymer electrolyte. The mechanical properties and thermal stability of the composite polymer electrolyte are improved, making it have better flexibility and resistance to thermal shrinkage. Adding modified graphene thereto can further improve its electrochemical activity and mechanical properties, thereby enhancing the ionic conductivity and mechanical stability of the composite polymer electrolyte. In addition, the modified graphene also has good dispersibility and compatibility with the polymer matrix, which helps to form a uniform electrolyte structure. Therefore, under the synergistic effect of the modified polymer and modified graphene oxide, the prepared electrolyte has excellent ionic conductivity, which is conducive to the rapid transmission of sodium ions, thereby improving the charge and discharge performance of the sodium ion battery. In addition, the electrolyte has excellent stability, which improves the safety and reliability of the sodium ion battery.

[0031] In the process of preparing the electrolyte, a modified polymer is first prepared. First, diethylene glycol and acryloyl chloride react, and the acyl chloride group on the acryloyl chloride reacts with a hydroxyl group on the diethylene glycol to introduce an alkenyl group to obtain an intermediate product I. Then, the intermediate product I reacts with phosphorus oxychloride, and the hydroxyl group on the intermediate product I reacts with three chlorine atoms on the phosphorus oxychloride to form an organic phosphorus compound containing three alkenyl groups to obtain an intermediate product II. Then, epichlorohydrin and vinylimidazole react to form an imidazolium cation containing an epoxy group to obtain an intermediate product III. Then, the alkenyl groups on the intermediate products II and III are polymerized under the initiation of azobisisobutyronitrile to obtain a modified polymer. The molecular structure of the modified polymer contains a large number of imidazolium cations, which are positively charged groups that can bind the anions of the sodium salt, which is beneficial to the Na + The migration of imidazolium cations gives the electrolyte excellent ionic conductivity, and it also contains organic phosphorus groups, which can give the electrolyte excellent high-temperature resistance and improve the safety of sodium-ion batteries. Moreover, since the modified polymer contains three alkenyl groups, the degree of cross-linking can be greatly improved during the polymerization process, forming an interpenetrating network, making the distribution of imidazolium cations more uniform, thereby improving the charge and discharge performance of sodium-ion batteries.

[0032] In the process of preparing the electrolyte, a modified graphene oxide is also prepared. First, graphene oxide is prepared using graphite powder, concentrated sulfuric acid and concentrated nitric acid as raw materials. Then, under the action of silane coupling agent KH-550, the graphene oxide is hydrolyzed to form silanols connected to the surface of the graphene oxide, thereby improving the dispersion performance of the graphene oxide and avoiding agglomeration. At the same time, amino groups are introduced to obtain modified graphene oxide. Graphene has excellent electrical conductivity. After the introduction of specific functional groups or doping with other elements, the electrochemical activity of the graphene is improved, thereby enhancing the ionic conductivity of the composite polymer electrolyte. Moreover, the introduced amino groups can react with the epoxy groups on the modified polymer, so that the modified graphene oxide is connected to the interpenetrating network of the modified polymer in the form of chemical bonds, thereby making the composite polymer electrolyte have excellent ionic conductivity and stability. DETAILED DESCRIPTION

[0033] 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.

[0034] Example 1:

[0035] This embodiment is a method for preparing a composite polymer electrolyte for a solid-state sodium ion battery, comprising the following steps:

[0036] Step S1: 0.12 mol diethylene glycol, 0.1 mol triethylamine, 0.18 g 4-dimethylaminopyridine and 40 mL toluene were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen protection was introduced. The mixture was stirred at a temperature of -10°C and a stirring rate of 400 r / min for 10 minutes. Then, 30 mL of acryloyl chloride was added dropwise while stirring. The acryloyl chloride solution formed by dissolving 0.1 mol:28 mL in toluene was added dropwise. The dropping rate was controlled to be 1 drop / s. After the addition was completed, the temperature was raised to 25°C and the stirring reaction was continued for 10 hours. After the reaction was completed, the reaction product was vacuum filtered, and the filtrate was washed twice with saturated brine and distilled water in sequence, and then extracted twice with dichloromethane. The extracts were combined and the extracts were rotary evaporated to remove the solvent to obtain intermediate product I;

[0037] Step S2: 0.1 mol intermediate product I, 0.12 mol triethylamine, 0.22 g 4-dimethylaminopyridine and 80 mL dichloromethane were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen protection was introduced. The mixture was stirred at a temperature of -10 ° C and a stirring rate of 400 r / min for 10 minutes. Then, 30 mL of phosphorus oxychloride was added dropwise while stirring. The phosphorus oxychloride solution formed by dissolving it in dichloromethane at a ratio of 0.1 mol:28 mL was added dropwise. The dropping rate was controlled to 1 drop / s. After the addition was completed, the temperature was raised to 25 ° C and the stirring reaction was continued for 10 hours. After the reaction was completed, the reaction product was vacuum filtered, and the filtrate was washed twice with saturated sodium bicarbonate solution and distilled water in sequence, and then dried over anhydrous sodium sulfate. After vacuum filtration, the filtrate was rotary evaporated to remove the solvent to obtain intermediate product II;

[0038] Step S3: 0.1 mol epichlorohydrin and 50 mL deionized water were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen protection was introduced. The mixture was stirred at 25°C and a stirring rate of 400 r / min for 10 minutes. Then, 0.1 mol vinyl imidazole was added dropwise while stirring at 60°C, and the dropping rate was controlled to 1 drop / s. After the addition was completed, the stirring reaction was continued for 3 hours. After the reaction was completed, the reaction product was rotary evaporated to remove the solvent, and then washed with ethyl acetate twice. Then, it was placed in a vacuum drying oven and dried at 40°C for 6 hours to obtain intermediate product III;

[0039] Step S4: 0.1 mol of intermediate product II, 0.1 mol of intermediate product III, 0.15 g of azobisisobutyronitrile and 100 mL of anhydrous ethanol were added to a three-necked flask equipped with a stirrer, a thermometer, a gas guide tube and a reflux condenser, and nitrogen was introduced for protection. The mixture was stirred at a temperature of 25° C. and a stirring rate of 400 r / min for 10 minutes, and then the temperature was raised to reflux and stirred for 5 hours. After the reaction was completed, the reaction product was cooled to room temperature, washed twice with anhydrous ether, and then rotary evaporated to remove the solvent to obtain a modified polymer;

[0040] Step S5: 1 g of graphite powder, 30 mL of 96% concentrated sulfuric acid, and 10 mL of 67% concentrated nitric acid were added to a three-necked flask equipped with a stirrer and a thermometer, and the mixture was stirred at -5 ° C. and a stirring rate of 400 r / min for 20 minutes. Then, 12 g of potassium permanganate was added and the stirring reaction was continued for 1 hour. After that, the mixture was heated to 50 ° C. and the stirring reaction was continued for 10 hours. After the reaction was completed, the reaction product was poured into 18% hydrogen peroxide, and then centrifuged. The precipitate was washed three times with 8% hydrochloric acid solution and distilled water, and then placed in a vacuum drying oven and dried at 60 ° C. for 2 hours to obtain graphene oxide;

[0041] Step S6: 1 g of graphene oxide, 2 mL of silane coupling agent KH-550, and 30 mL of 80% ethanol solution were added to a three-necked flask equipped with a stirrer, a thermometer, and a reflux condenser, and stirred at 25° C. and a stirring rate of 400 r / min for 20 minutes, then heated to reflux and continued to stir for 5 hours. After the reaction was completed, the reaction product was cooled to room temperature and then centrifuged. The precipitate was placed in a vacuum drying oven and dried at 50° C. for 2 hours to obtain modified graphene oxide;

[0042] Step S7: Weigh 10 parts of the modified polymer, 0.15 parts of the modified graphene oxide, 2 parts of sodium perchlorate, and 60 parts of anhydrous acetonitrile according to weight and set aside;

[0043] Step S8: The modified polymer, modified graphene oxide, sodium perchlorate and anhydrous acetonitrile are mixed uniformly at a temperature of 25°C and a stirring rate of 400 r / min, then poured into a PTFE mold, allowed to stand for 20 hours, then placed in a vacuum drying oven, dried at a temperature of 60°C for 3 hours, and then cut into pieces to obtain a composite polymer electrolyte for solid-state sodium ion batteries.

[0044] Example 2:

[0045] This embodiment is a method for preparing a composite polymer electrolyte for a solid-state sodium ion battery, comprising the following steps:

[0046] Step S1: 0.13 mol diethylene glycol, 0.1 mol triethylamine, 0.2 g 4-dimethylaminopyridine and 42 mL toluene were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen protection was introduced. The mixture was stirred at a temperature of -5°C and a stirring rate of 450 r / min for 12 minutes. Then, 30 mL of acryloyl chloride was added dropwise while stirring. The acryloyl chloride solution formed by dissolving 0.1 mol:29 mL in toluene was added dropwise. The dropping rate was controlled to be 1 drop / s. After the addition was completed, the temperature was raised to 28°C and the stirring reaction was continued for 12 hours. After the reaction was completed, the reaction product was vacuum filtered, and the filtrate was washed twice with saturated brine and distilled water in sequence, and then extracted twice with dichloromethane. The extracts were combined and the extracts were rotary evaporated to remove the solvent to obtain intermediate product I;

[0047] Step S2: 0.1 mol intermediate product I, 0.13 mol triethylamine, 0.25 g 4-dimethylaminopyridine and 90 mL dichloromethane were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen protection was introduced. The mixture was stirred for 12 minutes at a temperature of -5 ° C and a stirring rate of 450 r / min. Then, 32 mL of phosphorus oxychloride was added dropwise while stirring. The phosphorus oxychloride solution formed by dissolving trichlorophosphate in dichloromethane at a ratio of 0.1 mol:29 mL was added dropwise. The dropping rate was controlled to 1 drop / s. After the addition was completed, the temperature was raised to 28 ° C and the stirring reaction was continued for 12 hours. After the reaction was completed, the reaction product was vacuum filtered, and the filtrate was washed twice with saturated sodium bicarbonate solution and distilled water in sequence, and then dried over anhydrous sodium sulfate. After vacuum filtration, the filtrate was rotary evaporated to remove the solvent to obtain intermediate product II;

[0048] Step S3: 0.1 mol epichlorohydrin and 52 mL deionized water were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen protection was introduced. The mixture was stirred at 28 ° C. and a stirring rate of 450 r / min for 12 minutes. Then, 0.1 mol vinyl imidazole was added dropwise while stirring at 62 ° C. The dropping rate was controlled to 1 drop / s. After the addition was completed, the stirring reaction was continued for 4 hours. After the reaction was completed, the reaction product was rotary evaporated to remove the solvent, and then washed with ethyl acetate twice. Then, it was placed in a vacuum drying oven and dried at 42 ° C for 7 hours to obtain intermediate product III;

[0049] Step S4: 0.1 mol of intermediate product II, 0.25 mol of intermediate product III, 0.25 g of azobisisobutyronitrile and 110 mL of anhydrous ethanol were added to a three-necked flask equipped with a stirrer, a thermometer, a gas guide tube and a reflux condenser, and nitrogen was introduced for protection. The mixture was stirred at a temperature of 28° C. and a stirring rate of 450 r / min for 12 minutes, and then the temperature was raised to reflux and stirred for 5.5 hours. After the reaction was completed, the reaction product was cooled to room temperature, washed twice with anhydrous ether, and then rotary evaporated to remove the solvent to obtain a modified polymer;

[0050] Step S5: 1 g of graphite powder, 32 mL of 97% concentrated sulfuric acid, and 11 mL of 67% concentrated nitric acid were added to a three-necked flask equipped with a stirrer and a thermometer, and the mixture was stirred at -3 ° C and a stirring rate of 450 r / min for 25 minutes. Then, 14 g of potassium permanganate was added and the stirring reaction was continued for 1.5 hours. Then, the mixture was heated to 52 ° C and the stirring reaction was continued for 12 hours. After the reaction was completed, the reaction product was poured into 20% hydrogen peroxide, and then centrifuged. The precipitate was washed four times with 9% hydrochloric acid solution and distilled water, and then placed in a vacuum drying oven and dried at 65 ° C for 2.5 hours to obtain graphene oxide;

[0051] Step S6: 1 g of graphene oxide, 5 mL of silane coupling agent KH-550, and 35 mL of 82% ethanol solution were added to a three-necked flask equipped with a stirrer, a thermometer, and a reflux condenser, and stirred at 28° C. and a stirring rate of 450 r / min for 25 minutes, then heated to reflux and continued to stir for 5.5 hours. After the reaction was completed, the reaction product was cooled to room temperature and then centrifuged. The precipitate was placed in a vacuum drying oven and dried at 52° C. for 2.5 hours to obtain modified graphene oxide;

[0052] Step S7: Weigh 13 parts of the modified polymer, 0.8 parts of the modified graphene oxide, 3 parts of sodium perchlorate, and 70 parts of anhydrous acetonitrile according to weight and set aside;

[0053] Step S8: The modified polymer, modified graphene oxide, sodium perchlorate and anhydrous acetonitrile were mixed uniformly at a temperature of 28°C and a stirring rate of 450 r / min, then poured into a PTFE mold, allowed to stand for 25 hours, then placed in a vacuum drying oven, dried at a temperature of 62°C for 4 hours, and then cut into pieces to obtain a composite polymer electrolyte for solid-state sodium ion batteries.

[0054] Example 3:

[0055] This embodiment is a method for preparing a composite polymer electrolyte for a solid-state sodium ion battery, comprising the following steps:

[0056] Step S1: 0.15 mol diethylene glycol, 0.1 mol triethylamine, 0.22 g 4-dimethylaminopyridine and 45 mL toluene were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen was introduced for protection. The mixture was stirred at a temperature of 0°C and a stirring rate of 500 r / min for 15 minutes. Then, 30 mL of acryloyl chloride was added dropwise while stirring. The acryloyl chloride solution formed by dissolving 30 mL of acryloyl chloride in toluene at a ratio of 0.1 mol:30 mL was added dropwise. The dropping rate was controlled to be 2 drops / s. After the addition was completed, the temperature was raised to 30°C and the stirring reaction was continued for 15 hours. After the reaction was completed, the reaction product was vacuum filtered, and the filtrate was washed three times with saturated brine and distilled water in sequence. Then, it was extracted three times with dichloromethane. The extracts were combined and the extracts were rotary evaporated to remove the solvent to obtain intermediate product I.

[0057] Step S2: 0.1 mol intermediate product I, 0.15 mol triethylamine, 0.28 g 4-dimethylaminopyridine and 100 mL dichloromethane were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen protection was introduced. The mixture was stirred at a temperature of 0°C and a stirring rate of 500 r / min for 15 minutes. Then, 35 mL of phosphorus oxychloride was added dropwise while stirring. The phosphorus oxychloride solution formed by dissolving in dichloromethane at a ratio of 0.11 mol:30 mL was added dropwise. The dropping rate was controlled to 2 drops / s. After the addition was completed, the mixture was heated to 30°C and the stirring reaction was continued for 15 hours. After the reaction was completed, the reaction product was vacuum filtered, and the filtrate was washed three times with saturated sodium bicarbonate solution and distilled water in sequence, and then dried over anhydrous sodium sulfate. After vacuum filtration, the filtrate was rotary evaporated to remove the solvent to obtain intermediate product II;

[0058] Step S3: 0.1 mol epichlorohydrin and 55 mL deionized water were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen protection was introduced. The mixture was stirred at a temperature of 30°C and a stirring rate of 500 r / min for 15 minutes. Then, 0.1 mol vinyl imidazole was added dropwise while stirring at 65°C, and the dropping rate was controlled to 2 drops / s. After the addition was completed, the stirring reaction was continued for 5 hours. After the reaction was completed, the reaction product was rotary evaporated to remove the solvent, and then washed with ethyl acetate 3 times. Then, it was placed in a vacuum drying oven and dried at a temperature of 45°C for 8 hours to obtain intermediate product III;

[0059] Step S4: 0.1 mol of intermediate product II, 0.4 mol of intermediate product III, 0.35 g of azobisisobutyronitrile and 120 mL of anhydrous ethanol were added to a three-necked flask equipped with a stirrer, a thermometer, a gas guide tube and a reflux condenser, and nitrogen was introduced for protection. The mixture was stirred at a temperature of 30° C. and a stirring rate of 500 r / min for 15 minutes, and then the temperature was raised to reflux and stirred for 6 hours. After the reaction, the reaction product was cooled to room temperature, washed with anhydrous ether three times, and then rotary evaporated to remove the solvent to obtain a modified polymer;

[0060] Step S5: 1 g of graphite powder, 35 mL of 98% concentrated sulfuric acid, and 12 mL of 68% concentrated nitric acid were added to a three-necked flask equipped with a stirrer and a thermometer, and the mixture was stirred at 0°C and a stirring rate of 500 r / min for 30 minutes. Then, 16 g of potassium permanganate was added and the mixture was stirred for 2 hours. The mixture was then heated to 55°C and stirred for 15 hours. After the reaction was completed, the reaction product was poured into 22% hydrogen peroxide, and then centrifuged. The precipitate was washed 5 times with 10% hydrochloric acid solution and distilled water, and then placed in a vacuum drying oven and dried at 70°C for 3 hours to obtain graphene oxide.

[0061] Step S6: 1 g of graphene oxide, 8 mL of silane coupling agent KH-550, and 40 mL of 85% ethanol solution were added to a three-necked flask equipped with a stirrer, a thermometer, and a reflux condenser, and stirred for reaction at a temperature of 30° C. and a stirring rate of 500 r / min for 30 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 placed in a vacuum drying oven and dried at a temperature of 55° C. for 3 hours to obtain modified graphene oxide;

[0062] Step S7: Weigh 16 parts of the modified polymer, 1.5 parts of the modified graphene oxide, 4 parts of sodium perchlorate, and 80 parts of anhydrous acetonitrile according to weight and set aside;

[0063] Step S8: The modified polymer, modified graphene oxide, sodium perchlorate and anhydrous acetonitrile were mixed uniformly at a temperature of 30°C and a stirring rate of 500 r / min, then poured into a PTFE mold, allowed to stand for 30 hours, and then placed in a vacuum drying oven and dried at a temperature of 65°C for 5 hours. The resulting mixture was then cut into pieces to obtain a composite polymer electrolyte for solid-state sodium ion batteries.

[0064] Comparative Example 1:

[0065] This comparative example is a method for preparing a composite polymer electrolyte for a solid-state sodium ion battery, comprising the following steps:

[0066] Step S1: 0.15 mol diethylene glycol, 0.1 mol triethylamine, 0.22 g 4-dimethylaminopyridine and 45 mL toluene were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen was introduced for protection. The mixture was stirred at a temperature of 0°C and a stirring rate of 500 r / min for 15 minutes. Then, 30 mL of acryloyl chloride was added dropwise while stirring. The acryloyl chloride solution formed by dissolving 30 mL of acryloyl chloride in toluene at a ratio of 0.1 mol:30 mL was added dropwise. The dropping rate was controlled to be 2 drops / s. After the addition was completed, the temperature was raised to 30°C and the stirring reaction was continued for 15 hours. After the reaction was completed, the reaction product was vacuum filtered, and the filtrate was washed three times with saturated brine and distilled water in sequence. Then, it was extracted three times with dichloromethane. The extracts were combined and the extracts were rotary evaporated to remove the solvent to obtain intermediate product I.

[0067] Step S2: 0.1 mol intermediate product I, 0.15 mol triethylamine, 0.28 g 4-dimethylaminopyridine and 100 mL dichloromethane were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen protection was introduced. The mixture was stirred at a temperature of 0°C and a stirring rate of 500 r / min for 15 minutes. Then, 35 mL of phosphorus oxychloride was added dropwise while stirring. The phosphorus oxychloride solution formed by dissolving in dichloromethane at a ratio of 0.11 mol:30 mL was added dropwise. The dropping rate was controlled to 2 drops / s. After the addition was completed, the mixture was heated to 30°C and the stirring reaction was continued for 15 hours. After the reaction was completed, the reaction product was vacuum filtered, and the filtrate was washed three times with saturated sodium bicarbonate solution and distilled water in sequence, and then dried over anhydrous sodium sulfate. After vacuum filtration, the filtrate was rotary evaporated to remove the solvent to obtain intermediate product II;

[0068] Step S3: 0.1 mol epichlorohydrin and 55 mL deionized water were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen protection was introduced. The mixture was stirred at a temperature of 30°C and a stirring rate of 500 r / min for 15 minutes. Then, 0.1 mol vinyl imidazole was added dropwise while stirring at 65°C, and the dropping rate was controlled to 2 drops / s. After the addition was completed, the stirring reaction was continued for 5 hours. After the reaction was completed, the reaction product was rotary evaporated to remove the solvent, and then washed with ethyl acetate 3 times. Then, it was placed in a vacuum drying oven and dried at a temperature of 45°C for 8 hours to obtain intermediate product III;

[0069] Step S4: 0.1 mol of intermediate product II, 0.4 mol of intermediate product III, 0.35 g of azobisisobutyronitrile and 120 mL of anhydrous ethanol were added to a three-necked flask equipped with a stirrer, a thermometer, a gas guide tube and a reflux condenser, and nitrogen was introduced for protection. The mixture was stirred at a temperature of 30° C. and a stirring rate of 500 r / min for 15 minutes, and then the temperature was raised to reflux and stirred for 6 hours. After the reaction, the reaction product was cooled to room temperature, washed with anhydrous ether three times, and then rotary evaporated to remove the solvent to obtain a modified polymer;

[0070] Step S5: Weigh 16 parts of the modified polymer, 4 parts of sodium perchlorate, and 80 parts of anhydrous acetonitrile according to weight and set aside;

[0071] Step S6: The modified polymer, sodium perchlorate and anhydrous acetonitrile were mixed uniformly at a temperature of 30°C and a stirring rate of 500 r / min, then poured into a PTFE mold, allowed to stand for 30 hours, then placed in a vacuum drying oven, dried at a temperature of 65°C for 5 hours, and then cut into pieces to obtain a composite polymer electrolyte for solid-state sodium ion batteries.

[0072] Comparative Example 2:

[0073] This comparative example is a method for preparing a composite polymer electrolyte for a solid-state sodium ion battery, comprising the following steps:

[0074] Step S1: 0.15 mol diethylene glycol, 0.1 mol triethylamine, 0.22 g 4-dimethylaminopyridine and 45 mL toluene were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen was introduced for protection. The mixture was stirred at a temperature of 0°C and a stirring rate of 500 r / min for 15 minutes. Then, 30 mL of acryloyl chloride was added dropwise while stirring. The acryloyl chloride solution formed by dissolving 30 mL of acryloyl chloride in toluene at a ratio of 0.1 mol:30 mL was added dropwise. The dropping rate was controlled to be 2 drops / s. After the addition was completed, the temperature was raised to 30°C and the stirring reaction was continued for 15 hours. After the reaction was completed, the reaction product was vacuum filtered, and the filtrate was washed three times with saturated brine and distilled water in sequence. Then, it was extracted three times with dichloromethane. The extracts were combined and the extracts were rotary evaporated to remove the solvent to obtain intermediate product I.

[0075] Step S2: 0.1 mol intermediate product I, 0.15 mol triethylamine, 0.28 g 4-dimethylaminopyridine and 100 mL dichloromethane were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen protection was introduced. The mixture was stirred at a temperature of 0°C and a stirring rate of 500 r / min for 15 minutes. Then, 35 mL of phosphorus oxychloride was added dropwise while stirring. The phosphorus oxychloride solution formed by dissolving in dichloromethane at a ratio of 0.11 mol:30 mL was added dropwise. The dropping rate was controlled to 2 drops / s. After the addition was completed, the mixture was heated to 30°C and the stirring reaction was continued for 15 hours. After the reaction was completed, the reaction product was vacuum filtered, and the filtrate was washed three times with saturated sodium bicarbonate solution and distilled water in sequence, and then dried over anhydrous sodium sulfate. After vacuum filtration, the filtrate was rotary evaporated to remove the solvent to obtain intermediate product II;

[0076] Step S3: 0.1 mol epichlorohydrin and 55 mL deionized water were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen protection was introduced. The mixture was stirred at a temperature of 30°C and a stirring rate of 500 r / min for 15 minutes. Then, 0.1 mol vinyl imidazole was added dropwise while stirring at 65°C, and the dropping rate was controlled to 2 drops / s. After the addition was completed, the stirring reaction was continued for 5 hours. After the reaction was completed, the reaction product was rotary evaporated to remove the solvent, and then washed with ethyl acetate 3 times. Then, it was placed in a vacuum drying oven and dried at a temperature of 45°C for 8 hours to obtain intermediate product III;

[0077] Step S4: 0.1 mol of intermediate product II, 0.4 mol of intermediate product III, 0.35 g of azobisisobutyronitrile and 120 mL of anhydrous ethanol were added to a three-necked flask equipped with a stirrer, a thermometer, a gas guide tube and a reflux condenser, and nitrogen was introduced for protection. The mixture was stirred at a temperature of 30° C. and a stirring rate of 500 r / min for 15 minutes, and then the temperature was raised to reflux and stirred for 6 hours. After the reaction, the reaction product was cooled to room temperature, washed with anhydrous ether three times, and then rotary evaporated to remove the solvent to obtain a modified polymer;

[0078] Step S5: 1 g of graphite powder, 35 mL of 98% concentrated sulfuric acid, and 12 mL of 68% concentrated nitric acid were added to a three-necked flask equipped with a stirrer and a thermometer, and the mixture was stirred at 0°C and a stirring rate of 500 r / min for 30 minutes. Then, 16 g of potassium permanganate was added and the mixture was stirred for 2 hours. The mixture was then heated to 55°C and stirred for 15 hours. After the reaction was completed, the reaction product was poured into 22% hydrogen peroxide, and then centrifuged. The precipitate was washed 5 times with 10% hydrochloric acid solution and distilled water, and then placed in a vacuum drying oven and dried at 70°C for 3 hours to obtain graphene oxide.

[0079] Step S6: Weigh 16 parts of the modified polymer, 1.5 parts of graphene oxide, 4 parts of sodium perchlorate, and 80 parts of anhydrous acetonitrile according to weight and set aside;

[0080] Step S7: The modified polymer, graphene oxide, sodium perchlorate and anhydrous acetonitrile were mixed uniformly at a temperature of 30°C and a stirring rate of 500 r / min, then poured into a PTFE mold, allowed to stand for 30 hours, then placed in a vacuum drying oven, dried at a temperature of 65°C for 5 hours, and then cut into pieces to obtain a composite polymer electrolyte for solid-state sodium ion batteries.

[0081] Comparative Example 3:

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

[0083] Step S1: 1 g of graphite powder, 35 mL of 98% concentrated sulfuric acid, and 12 mL of 68% concentrated nitric acid were added to a three-necked flask equipped with a stirrer and a thermometer, and stirred at 0°C and a stirring rate of 500 r / min for 30 minutes. Then, 16 g of potassium permanganate was added and the stirring reaction was continued for 2 hours. Then, the temperature was raised to 55°C and the stirring reaction was continued for 15 hours. After the reaction was completed, the reaction product was poured into 22% hydrogen peroxide, and then centrifuged. The precipitate was washed 5 times with 10% hydrochloric acid solution and distilled water, and then placed in a vacuum drying oven and dried at 70°C for 3 hours to obtain graphene oxide;

[0084] Step S2: 1 g of graphene oxide, 8 mL of silane coupling agent KH-550, and 40 mL of 85% ethanol solution were added to a three-necked flask equipped with a stirrer, a thermometer, and a reflux condenser, and stirred at 30° C. and a stirring rate of 500 r / min for 30 minutes, then heated to reflux and continued to stir for 6 hours. After the reaction was completed, the reaction product was cooled to room temperature and then centrifuged. The precipitate was placed in a vacuum drying oven and dried at 55° C. for 3 hours to obtain modified graphene oxide;

[0085] Step S3: 16 parts of polyethylene oxide (Mw=300,000), 1.5 parts of modified graphene oxide, 4 parts of sodium perchlorate, and 80 parts of anhydrous acetonitrile were weighed in parts by weight and set aside;

[0086] Step S4: Polyethylene oxide, modified graphene oxide, sodium perchlorate and anhydrous acetonitrile are mixed uniformly at a temperature of 30°C and a stirring rate of 500 r / min, then poured into a PTFE mold, allowed to stand for 30 hours, then placed in a vacuum drying oven, dried at a temperature of 65°C for 5 hours, and then cut into pieces to obtain a composite polymer electrolyte for solid-state sodium ion batteries.

[0087] The composite polymer electrolytes for the solid-state sodium ion batteries of Examples 1-3 and Comparative Examples 1-3 were used to assemble stainless steel / polymer solid electrolyte / stainless steel symmetrical cells, and the cells were tested. The test results are shown below:

[0088] sample Ionic conductivity at 60℃, mS / cm Initial discharge capacity at 0.5C, mAh / g Example 1 3.95×10 147.8 Example 2 4.31×10 150.1 Example 3 4.69×10 152.6 Comparative Example 1 6.89×10 101.2 Comparative Example 2 3.08×10 136.4 Comparative Example 3 1.21×10 118.6

[0089] Referring to the data in the above table, based on the comparison between Examples 1-3 and Comparative Examples 1-3, it can be seen that the composite polymer electrolyte for solid-state sodium ion batteries of the present invention has excellent electrochemical performance.

[0090] 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.

[0091] 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 composite polymer electrolyte for solid-state sodium ion batteries, characterized in that It comprises the following components in parts by weight: 10-16 parts of modified polymer, 0.15-1.5 parts of modified graphene oxide, 2-4 parts of sodium perchlorate and 60-80 parts of anhydrous acetonitrile; Wherein, the modified polymer is prepared by the following steps: Step a1: diethylene glycol, triethylamine, 4-dimethylaminopyridine, and toluene are stirred for reaction, and then acryloyl chloride solution is added dropwise while stirring. After the addition is complete, stirring is continued. After the reaction is completed, the reaction product is vacuum filtered, the filtrate is washed and extracted, and the extract is rotary evaporated to obtain intermediate product I; Step a2: reacting the intermediate product I, triethylamine, 4-dimethylaminopyridine and dichloromethane with stirring, then adding the phosphorus oxychloride solution dropwise with stirring, and continuing to stir the reaction after the addition is complete. After the reaction is completed, the reaction product is vacuum filtered, the filtrate is washed and dried, and then vacuum filtered, and the filtrate is rotary evaporated to obtain the intermediate product II; Step a3: stirring epichlorohydrin and deionized water to react, then adding vinyl imidazole dropwise while stirring, and continuing to stir the reaction after the addition is complete. After the reaction is complete, the reaction product is rotary evaporated, washed, and dried to obtain intermediate product III; Step a4: stirring and reacting the intermediate product II, the intermediate product III, azobisisobutyronitrile and anhydrous ethanol. After the reaction is completed, the reaction product is cooled, washed, and then rotary evaporated to obtain a modified polymer; The modified graphene oxide is prepared by the following steps: Step b1: stirring graphite powder, concentrated sulfuric acid and concentrated nitric acid to react, then adding potassium permanganate and continuing the stirring reaction. After the reaction is completed, pouring the reaction product into hydrogen peroxide, then centrifuging, washing and drying the precipitate to obtain graphene oxide; Step b2: stirring the graphene oxide, the silane coupling agent KH-550 and the ethanol solution to react, cooling the reaction product after the reaction is completed, then centrifuging, and drying the precipitate to obtain modified graphene oxide.

2. A composite polymer electrolyte for solid-state sodium ion batteries according to claim 1, characterized in that: The usage ratio of the diethylene glycol, triethylamine, 4-dimethylaminopyridine, toluene and acryloyl chloride solution in step a1 is 0.12-0.15 mol: 0.1 mol: 0.18-0.22 g: 40-45 mL: 30 mL; the acryloyl chloride solution in step a1 is a solution formed by dissolving acryloyl chloride in toluene at a ratio of 0.1 mol: 28-30 mL.

3. A composite polymer electrolyte for solid-state sodium ion batteries according to claim 1, characterized in that: The amount ratio of the intermediate product I, triethylamine, 4-dimethylaminopyridine, dichloromethane and phosphorus oxychloride solution in step a2 is 0.1 mol: 0.12-0.15 mol: 0.22-0.28 g: 80-100 mL: 30-35 mL; the phosphorus oxychloride solution in step a2 is a solution formed by dissolving phosphorus oxychloride in dichloromethane according to 0.1-0.11 mol: 28-30 mL.

4. A composite polymer electrolyte for solid-state sodium ion batteries according to claim 1, characterized in that: The usage ratio of the epichlorohydrin, deionized water and vinyl imidazole in step a3 is 0.1 mol:50-55 mL:0.1 mol.

5. A composite polymer electrolyte for solid-state sodium ion batteries according to claim 1, characterized in that: The usage ratio of the intermediate product II, intermediate product III, azobisisobutyronitrile and anhydrous ethanol in step a4 is 0.1 mol: 0.1-0.4 mol: 0.15-0.35 g: 100-120 mL.

6. A composite polymer electrolyte for solid-state sodium ion batteries according to claim 1, characterized in that: The amount ratio of the graphite powder, concentrated sulfuric acid, concentrated nitric acid and potassium permanganate in step b1 is 1g:30-35mL:10-12mL:12-16g; the mass fraction of the concentrated sulfuric acid in step b1 is 96-98%, the mass fraction of the concentrated nitric acid is 67-68%, and the mass fraction of the hydrogen peroxide is 18-22%.

7. A composite polymer electrolyte for solid-state sodium ion batteries according to claim 1, characterized in that: The usage ratio of the graphene oxide, silane coupling agent KH-550 and ethanol solution in step b2 is 1 g: 2-8 mL: 30-40 mL; the volume fraction of the ethanol solution in step b2 is 80-85%.

8. The composite polymer electrolyte for solid-state sodium ion batteries according to claim 1, characterized in that: The composite polymer electrolyte is prepared by the following steps: Step 1: Weigh 10-16 parts of modified polymer, 0.15-1.5 parts of modified graphene oxide, 2-4 parts of sodium perchlorate and 60-80 parts of anhydrous acetonitrile according to weight parts and set aside; Step 2: The modified polymer, modified graphene oxide, sodium perchlorate and anhydrous acetonitrile are mixed evenly at a temperature of 25-30°C and a stirring rate of 400-500r / min, then poured into a PTFE mold, and then allowed to stand for 20-30 hours. Then, the mold is placed in a vacuum drying oven and dried at a temperature of 60-65°C for 3-5 hours. The mold is then cut into pieces to obtain a composite polymer electrolyte for solid-state sodium ion batteries.