A long-life, wide electrochemical window polymer solid electrolyte and its preparation method

Abstract

The present invention discloses a method for preparing a long-life, wide-electrochemical-window polymer solid-state electrolyte, comprising the following steps: S1: reacting a quinoline compound with sodium metal to obtain a biquinoline intermediate; S2: reacting the intermediate with a brominated alkane; then sequentially adding vinyl bromide and divinyl ether to react to obtain a monoolefin biquinolinium compound; S3: reacting the biquinoline intermediate with a brominated alkene to obtain a diolefin biquinolinium compound; S4: reacting polymethylhydrogensiloxane with the monoolefin biquinolinium compound in the presence of a catalyst to obtain a modified polymethylhydrogensiloxane; and S5: mixing the intermediate with the diolefin biquinolinium compound, a catalyst, and lithium bis(trifluoromethylsulfonyl)imide, and heating to crosslink and solidify the resultant polymer solid-state electrolyte. The polymer solid-state electrolyte prepared by the present invention not only achieves a wide electrochemical window but also ensures long-life, stable operation, meeting the requirements of high-safety batteries.

Description

Technical Field

[0001] The present invention relates to the technical field of solid electrolytes, and in particular to a long-life wide electrochemical window polymer solid electrolyte and a preparation method thereof. Background Art

[0002] Solid-state electrolytes, as a core component of lithium-ion batteries, play a crucial role in improving their energy density, safety, and cycle stability. While traditional liquid electrolytes offer high ionic conductivity, they suffer from issues such as leakage, flammability, and poor chemical stability, limiting further improvements in battery performance and the expansion of their applications. To overcome these shortcomings, solid-state electrolytes have garnered widespread attention due to their non-flammability, lack of leakage, and excellent thermal stability.

[0003] Solid-state electrolytes are mainly divided into two categories: inorganic and organic. Inorganic solid-state electrolytes such as oxides and sulfides generally have high ionic conductivity, but they have poor interfacial compatibility with electrode materials, resulting in increased interfacial resistance and affecting the overall performance of the battery. On the other hand, organic solid-state electrolytes, especially those based on polysiloxane, show great potential due to their good mechanical properties and flexibility. However, their narrow electrochemical window limits their application in high-voltage battery systems.

[0004] Currently, researchers are committed to developing new solid-state electrolyte materials to achieve high ionic conductivity, a wide electrochemical window, and excellent interfacial compatibility. These materials need to have good electrochemical performance at room temperature while remaining stable at high voltages to meet the needs of next-generation high-energy-density batteries. Although some progress has been made, developing solid-state electrolytes with long life and a wide electrochemical window remains a challenge and requires further research and innovation. Summary of the Invention

[0005] In view of the above shortcomings of the prior art, the present invention provides a method for preparing a long-life wide electrochemical window polymer solid electrolyte to solve the problems of existing solid electrolytes such as insufficient stability at high voltage, narrow electrochemical window, and easy performance degradation during long-term cyclic use. Specifically, the electrolyte materials in the prior art often face challenges such as easy decomposition during high voltage operation, large changes in conductivity with temperature, and insufficient mechanical properties. These problems limit the performance and application range of solid-state batteries. The present invention aims to overcome these limitations through innovative polymer design and preparation processes, and provide a polymer solid electrolyte with better comprehensive performance to meet the needs of high energy density and high safety solid-state batteries.

[0006] In order to achieve the above objects, the technical solution adopted by the present invention is:

[0007] A method for preparing a long-life, wide-electrochemical-window polymer solid electrolyte, the method comprising the following steps:

[0008] S1: heating a quinoline compound and sodium metal to react for a certain period of time, and separating to obtain a 4,4'-biquinoline intermediate (as shown in structural formula I);

[0009] , wherein R1, R2, R3, and R4 are independently selected from hydrogen or methyl;

[0010] S2: The 4,4'-biquinoline intermediate obtained in step S1 is first subjected to a mono-substitution reaction with a brominated alkane; vinyl bromide is then added for a di-substitution reaction, followed by addition reaction with divinyl ether, and finally an anion exchange reaction with an aqueous solution containing a fluorine anion to obtain a mono-olefin biquinolinium compound (as shown in structural formula II);

[0011] , wherein R5 is an alkane with 2 to 5 carbon atoms; n is 1, 2 or 3; X - is tetrafluoroborate, trifluoromethanesulfonate or hexafluorophosphate;

[0012] S3: performing a disubstituted reaction of the 4,4'-biquinoline intermediate obtained in step S1 with a brominated olefin; then adding an aqueous solution containing a fluorine anion to perform an anion exchange reaction to obtain a diolefin biquinolinium compound (as shown in structural formula III);

[0013] , wherein R6 and R7 are independently selected from olefins having 3 to 6 carbon atoms; X - is tetrafluoroborate, trifluoromethanesulfonate or hexafluorophosphate;

[0014] S4: dissolving a certain amount of polymethyl hydrogen siloxane in a solvent by heating and stirring, adding a mixture of the monoolefin biquinolinium compound obtained in step S2, a catalyst, and a solvent, and heating and reacting under inert atmosphere to obtain modified polymethyl hydrogen siloxane;

[0015] S5: The modified polymethylhydrogensiloxane obtained in step S4 is stirred and dissolved in a solvent, and then the diolefin biquinolinium compound, catalyst and lithium bis(trifluoromethylsulfonylimide) obtained in step S3 are added, and the mixture is stirred and mixed evenly at room temperature. The mixture is placed in a vacuum oven and heated for cross-linking and curing to obtain the polymer solid electrolyte.

[0016] The present invention synthesizes 4,4'-biquinolinium grafted modified polymethylhydrogen siloxane through steps S1, S2 and S4. By introducing biquinolinium, it not only achieves intrinsic conductive properties and significantly improves the electrochemical activity and ionic conductivity of the electrolyte, but also the conjugated structure of biquinolinium further enhances the electrochemical window and thermal stability of the electrolyte. In addition, the 4,4'-biquinolinium grafted modified polymethylhydrogen siloxane also enhances the mechanical strength of the electrolyte, allowing it to maintain structural stability during the long-term cycle of the battery. At the same time, the introduced ether functional group further increases the flexibility of the solid electrolyte and promotes ion migration, thereby improving the ionic conductivity of the electrolyte, especially the electrochemical performance over a wide temperature range.

[0017] The present invention also synthesizes a 4,4'-biquinolinium compound with a diolefin structure through steps S1 and S3. In step S5, this compound acts as a highly efficient crosslinker and reacts with the remaining Si-H bonds in polymethylhydrogensiloxane under the action of a catalyst to produce a polymer solid electrolyte with a three-dimensional crosslinked network structure exhibiting high electrochemical stability and excellent mechanical properties. In this process, lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) is used as the lithium salt. Its excellent ionic conductivity not only improves the electrolyte's ionic conductivity, but also its chemical stability and compatibility with electrode materials further enhance the electrolyte's performance. The polymer solid electrolyte of this invention not only exhibits a wider electrochemical window, ensuring chemical stability under high-voltage operation, but also exhibits excellent chemical and electrochemical stability and good interfacial compatibility with electrode materials through in-situ polymerization and curing. These properties provide an important material foundation for the development of high-energy-density, high-safety solid-state batteries, while also strongly supporting the battery's long cycle life and wide operating temperature range.

[0018] As a preferred technical solution, in step S4, the heating reaction is first carried out at a temperature of 45-55° C. for 2-4 hours, and then the temperature is raised to 80-90° C. for a further 2-4 hours.

[0019] As a preferred technical solution, the quinoline compound is at least one of quinoline, 3-methylquinoline, 5-methylquinoline, 6-methylquinoline, 7-methylquinoline, 8-methylquinoline, 2,3-dimethylquinoline, 2,6-dimethylquinoline, 2,7-dimethylquinoline, 2,8-dimethylquinoline, 5,8-dimethylquinoline, 6,7-dimethylquinoline, 6,8-dimethylquinoline, 2,6,7-trimethylquinoline, 2,6,8-trimethylquinoline, 2,5,7-trimethylquinoline, 2,7,8-trimethylquinoline, and 2,5,8-trimethylquinoline.

[0020] As a preferred technical solution, the brominated alkane is at least one of ethyl bromide, propyl bromide, butyl bromide, and pentane bromide.

[0021] As a preferred technical solution, the divinyl ether is at least one of ethylene glycol divinyl ether, diethylene glycol divinyl ether, and triethylene glycol divinyl ether.

[0022] As a preferred technical solution, the fluorine-containing anion is at least one of tetrafluoroborate, trifluoromethanesulfonate, and hexafluorophosphate.

[0023] As a preferred technical solution, the brominated olefin is at least one of 3-bromopropylene, 3-bromo-2-methylpropylene, 3-bromo-1-butene, 4-bromo-2-methyl-1-butene, 5-bromo-1-pentene, 5-bromo-1-hexene, and 6-bromo-1-hexene.

[0024] As a preferred technical solution, the catalyst is at least one of chloroplatinic acid, palladium acetate, and nickel acetate.

[0025] As a preferred technical solution, the mass ratio of the monoolefin biquinolinium compound to polymethyl hydrogen siloxane is 10 to 15:1.

[0026] As a preferred technical solution, the mass ratio of the diolefin biquinolinium compound to the modified polymethyl hydrogen siloxane is 2 to 3:1.

[0027] Another aspect of the present invention is to provide a long-life wide electrochemical window polymer solid electrolyte, which is prepared using the above-mentioned method for preparing the long-life wide electrochemical window polymer solid electrolyte.

[0028] Beneficial effects of the present invention:

[0029] The long-life wide electrochemical window polymer solid electrolyte prepared by the present invention not only achieves stable operation under a wide electrochemical window, ensuring the safety and reliability of the battery under high voltage conditions, but also significantly improves the long-life characteristics of the electrolyte through optimized chemical structure and cross-linked network design, allowing the battery to undergo more charge and discharge cycles without performance degradation. In addition, the electrolyte of the present invention also has good mechanical properties and thermal stability, further enhancing the environmental adaptability and durability of the battery. In addition, the preparation method of the present invention is simple to operate and easy to scale production, which is conducive to reducing costs and promoting the commercialization process of solid-state battery technology. DETAILED DESCRIPTION

[0030] The following description is intended to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are merely examples, and those skilled in the art may conceive of other obvious variations.

[0031] Example 1

[0032] The method for preparing the long-life and wide electrochemical window polymer solid electrolyte of this embodiment comprises the following steps:

[0033] S1: Add 0.2 mol of quinoline and 0.05 mol of sodium metal to a reaction flask, heat to 120°C for 24 hours, cool to room temperature, and pour into ice to complete the reaction of excess sodium metal; after oil-water separation, add anhydrous sodium sulfate to the resulting oil, let it stand overnight, and then remove excess quinoline by rotary evaporation under reduced pressure; the product obtained after rotary evaporation is recrystallized in ethanol solution to obtain a 4,4'-biquinoline intermediate.

[0034] S2: Dissolve 0.04 mol of the 4,4'-biquinoline intermediate obtained in step S1 in 50 mL of acetonitrile solution, add 0.04 mol of ethyl bromide to carry out a monosubstitution reaction for 5 hours; then add 0.042 mol of vinyl bromide to carry out a disubstitution reaction for 5 hours, then add 0.042 mol of triethylene glycol divinyl ether and an appropriate amount of initiator, heat to 60°C for an addition reaction for 1 hour, and finally add a 30% mass concentration of sodium tetrafluoroborate aqueous solution to carry out anion exchange reaction. After separation, a monoolefin biquinolinium compound is obtained.

[0035] S3: Dissolve 0.04 mol of the 4,4'-biquinoline intermediate obtained in step S1 in 50 mL of acetonitrile solution, add 0.085 mol of 3-bromopropene to carry out a disubstitution reaction for 6 hours; then add a 30% mass concentration of sodium tetrafluoroborate aqueous solution to carry out an anion exchange reaction, and after separation, obtain a diolefin biquinolinium compound.

[0036] S4: 55 g of polymethyl hydrogen siloxane (average molecular weight of 2100) was dissolved in 100 mL of xylene solvent with heating and stirring, and a mixture prepared by 5.8 g of the monoolefin biquinolinium compound obtained in step S2, 0.8 g of catalyst chloroplatinic acid and 100 mL of xylene solvent was added. The mixture was heated to react under nitrogen atmosphere. The heating reaction was first carried out at a temperature of 45°C for 3 hours, then the temperature was raised to 80°C and the reaction was continued for 4 hours. After separation, the modified polymethyl hydrogen siloxane was obtained.

[0037] S5: 30 g of the modified polymethylhydrogensiloxane obtained in step S4 was stirred and dissolved in 60 mL of solvent xylene, followed by the addition of 10 g of the diolefin biquinolinium compound obtained in step S3, 0.5 g of catalyst chloroplatinic acid, and 4.5 g of lithium bis(trifluoromethylsulfonyl)imide. The mixture was stirred and mixed evenly at room temperature, placed in a vacuum oven, and heated to 105° C. for cross-linking and curing reaction for 24 hours to obtain the polymer solid electrolyte.

[0038] Example 2

[0039] The method for preparing the long-life and wide electrochemical window polymer solid electrolyte of this embodiment comprises the following steps:

[0040] S1: Add 0.2 mol of 6-methylquinoline and 0.05 mol of sodium metal to a reaction flask, heat to 120°C for 24 hours, cool to room temperature, and pour into ice to complete the reaction of excess sodium metal; after oil-water separation, add anhydrous sodium sulfate to the resulting oil, let it stand overnight, and then remove excess quinoline by rotary evaporation under reduced pressure; the product obtained after rotary evaporation is recrystallized in ethanol solution to obtain a 4,4'-biquinoline intermediate.

[0041] S2: Dissolve 0.04 mol of the 4,4'-biquinoline intermediate obtained in step S1 in 50 mL of acetonitrile solution, add 0.04 mol of bromopropane to carry out a monosubstitution reaction for 5 h; then add 0.042 mol of vinyl bromide to carry out a disubstitution reaction for 5 h, then add 0.042 mol of diethylene glycol divinyl ether and an appropriate amount of initiator, heat to 60°C for an addition reaction for 1 h, and finally add a 30% mass concentration of sodium trifluoromethanesulfonate aqueous solution to carry out anion exchange reaction. After separation, a monoolefin biquinolinium compound is obtained.

[0042] S3: 0.04 mol of the 4,4'-biquinoline intermediate obtained in step S1 was dissolved in 50 mL of acetonitrile solution, and 0.085 mol of 3-bromo-2-methylpropene was added to carry out a disubstitution reaction for 6 hours; then, a 30% mass concentration of sodium trifluoromethanesulfonate aqueous solution was added to carry out an anion exchange reaction, and after separation, a diolefin biquinolinium compound was obtained.

[0043] S4: 55 g of polymethyl hydrogen siloxane (average molecular weight of 2100) was dissolved in 100 mL of xylene solvent with heating and stirring, and a mixture prepared by 6.2 g of the monoolefin biquinolinium compound obtained in step S2, 0.8 g of catalyst chloroplatinic acid and 100 mL of xylene solvent was added. The mixture was heated to react under nitrogen atmosphere. The heating reaction was first carried out at a temperature of 55°C for 2 hours, then the temperature was raised to 90°C and the reaction was continued for 2 hours. After separation, the modified polymethyl hydrogen siloxane was obtained.

[0044] S5: 30 g of the modified polymethylhydrogensiloxane obtained in step S4 was stirred and dissolved in 60 mL of xylene solvent, followed by the addition of 11 g of the diolefin biquinolinium compound obtained in step S3, 0.5 g of catalyst chloroplatinic acid, and 4.5 g of lithium bis(trifluoromethylsulfonyl)imide. The mixture was stirred and mixed evenly at room temperature, placed in a vacuum oven, and heated to 105° C. for cross-linking and curing reaction for 24 hours to obtain the polymer solid electrolyte.

[0045] Example 3

[0046] The method for preparing the long-life and wide electrochemical window polymer solid electrolyte of this embodiment comprises the following steps:

[0047] S1: Add 0.2 mol 7-methylquinoline and 0.05 mol sodium metal to a reaction flask, heat to 120°C for 24 hours, cool to room temperature, and pour into ice to complete the reaction of excess sodium metal; after oil-water separation, add anhydrous sodium sulfate to the resulting oil, let it stand overnight, and then remove excess quinoline by rotary evaporation under reduced pressure; the product obtained after rotary evaporation is recrystallized in ethanol solution to obtain a 4,4'-biquinoline intermediate.

[0048] S2: Dissolve 0.04 mol of the 4,4'-biquinoline intermediate obtained in step S1 in 50 mL of acetonitrile solution, add 0.04 mol of bromobutane to carry out a monosubstitution reaction for 5 h; then add 0.042 mol of vinyl bromide to carry out a disubstitution reaction for 5 h, then add 0.042 mol of ethylene glycol divinyl ether and an appropriate amount of initiator, heat to 60°C to carry out an addition reaction for 1 h, and finally add a 30% mass concentration of sodium hexafluorophosphate aqueous solution to carry out anion exchange reaction. After separation, a monoolefin biquinolinium compound is obtained.

[0049] S3: 0.04 mol of the 4,4'-biquinoline intermediate obtained in step S1 was dissolved in 50 mL of acetonitrile solution, and 0.085 mol of 4-bromo-2-methyl-1-butene was added to carry out a disubstitution reaction for 6 hours; then, a 30% mass concentration of sodium hexafluorophosphate aqueous solution was added to carry out an anion exchange reaction, and after separation, a diolefin biquinolinium compound was obtained.

[0050] S4: 55 g of polymethyl hydrogen siloxane (average molecular weight of 2100) was dissolved in 100 mL of xylene solvent with heating and stirring, and a mixture prepared by 6.5 g of the monoolefin biquinolinium compound obtained in step S2, 0.8 g of catalyst chloroplatinic acid and 100 mL of xylene solvent was added. The mixture was heated to react under nitrogen atmosphere. The heating reaction was first carried out at a temperature of 50° C. for 4 h, then the temperature was raised to 80° C. and the reaction was continued for 4 h. After separation, the modified polymethyl hydrogen siloxane was obtained.

[0051] S5: 30 g of the modified polymethylhydrogensiloxane obtained in step S4 was stirred and dissolved in 60 mL of solvent xylene, followed by the addition of 12 g of the diolefin biquinolinium compound obtained in step S3, 0.5 g of catalyst chloroplatinic acid, and 4.5 g of lithium bis(trifluoromethylsulfonyl)imide. The mixture was stirred and mixed uniformly at room temperature, placed in a vacuum oven, and heated to 105° C. for cross-linking and curing reaction for 24 hours to obtain the polymer solid electrolyte.

[0052] Example 4

[0053] The method for preparing the long-life and wide electrochemical window polymer solid electrolyte of this embodiment comprises the following steps:

[0054] S1: Add 0.2 mol of 6,8-dimethylquinoline and 0.05 mol of sodium metal to a reaction flask, heat to 120°C for 24 hours, cool to room temperature, and pour into ice to complete the reaction of excess sodium metal; after oil-water separation, add anhydrous sodium sulfate to the resulting oil, let it stand overnight, and then remove excess quinoline by rotary evaporation under reduced pressure; the product obtained after rotary evaporation is recrystallized in ethanol solution to obtain a 4,4'-biquinoline intermediate.

[0055] S2: Dissolve 0.04 mol of the 4,4'-biquinoline intermediate obtained in step S1 in 50 mL of acetonitrile solution, add 0.04 mol of bromopentane to carry out a monosubstitution reaction for 5 h; then add 0.042 mol of vinyl bromide to carry out a disubstitution reaction for 5 h, then add 0.042 mol of diethylene glycol divinyl ether and an appropriate amount of initiator, heat to 60°C for an addition reaction for 1 h, and finally add a 30% mass concentration of sodium tetrafluoroborate aqueous solution to carry out anion exchange reaction. After separation, a monoolefin biquinolinium compound is obtained.

[0056] S3: Dissolve 0.04 mol of the 4,4'-biquinoline intermediate obtained in step S1 in 50 mL of acetonitrile solution, add 0.085 mol of 5-bromo-1-pentene to carry out a disubstitution reaction for 6 hours; then add a 30% mass concentration of sodium tetrafluoroborate aqueous solution to carry out an anion exchange reaction, and after separation, obtain a diolefin biquinolinium compound.

[0057] S4: 55 g of polymethyl hydrogen siloxane (average molecular weight of 2100) was dissolved in 100 mL of xylene solvent with heating and stirring, and a mixture prepared by 6.8 g of the monoolefin biquinolinium compound obtained in step S2, 0.8 g of catalyst chloroplatinic acid and 100 mL of xylene solvent was added. The mixture was heated to react under nitrogen atmosphere. The heating reaction was first carried out at a temperature of 50°C for 3 hours, then the temperature was raised to 80°C and the reaction was continued for 4 hours. After separation, the modified polymethyl hydrogen siloxane was obtained.

[0058] S5: 30 g of the modified polymethylhydrogensiloxane obtained in step S4 was stirred and dissolved in 60 mL of solvent xylene, followed by the addition of 13 g of the diolefin biquinolinium compound obtained in step S3, 0.5 g of catalyst chloroplatinic acid, and 4.5 g of lithium bis(trifluoromethylsulfonyl)imide. The mixture was stirred and mixed uniformly at room temperature, placed in a vacuum oven, and heated to 105° C. for cross-linking and curing reaction for 24 hours to obtain the polymer solid electrolyte.

[0059] Example 5

[0060] The method for preparing the long-life and wide electrochemical window polymer solid electrolyte of this embodiment comprises the following steps:

[0061] S1: Add 0.2 mol of 2,6,7-trimethylquinoline and 0.05 mol of sodium metal to a reaction flask, heat to 120°C for 24 hours, cool to room temperature, and pour into ice to complete the reaction of excess sodium metal; after oil-water separation, add anhydrous sodium sulfate to the resulting oil, let it stand overnight, and then remove excess quinoline by rotary evaporation under reduced pressure; the product obtained after rotary evaporation is recrystallized in ethanol solution to obtain a 4,4'-biquinoline intermediate.

[0062] S2: Dissolve 0.04 mol of the 4,4'-biquinoline intermediate obtained in step S1 in 50 mL of acetonitrile solution, add 0.04 mol of ethyl bromide to carry out a monosubstitution reaction for 5 h; then add 0.042 mol of vinyl bromide to carry out a disubstitution reaction for 5 h, then add 0.042 mol of ethylene glycol divinyl ether and an appropriate amount of initiator, heat to 60°C for an addition reaction for 1 h, and finally add a 30% mass concentration of sodium tetrafluoroborate aqueous solution to carry out anion exchange reaction. After separation, a monoolefin biquinolinium compound is obtained.

[0063] S3: Dissolve 0.04 mol of the 4,4'-biquinoline intermediate obtained in step S1 in 50 mL of acetonitrile solution, add 0.085 mol of 6-bromo-1-hexene to carry out a disubstitution reaction for 6 hours; then add a 30% mass concentration of sodium tetrafluoroborate aqueous solution to carry out an anion exchange reaction, and after separation, obtain a diolefin biquinolinium compound.

[0064] S4: 55 g of polymethyl hydrogen siloxane (average molecular weight of 2100) was dissolved in 100 mL of xylene solvent with heating and stirring, and a mixture prepared by 7.2 g of the monoolefin biquinolinium compound obtained in step S2, 0.8 g of catalyst chloroplatinic acid and 100 mL of xylene solvent was added. The mixture was heated to react under nitrogen atmosphere. The heating reaction was first carried out at a temperature of 50°C for 3 hours, then the temperature was raised to 90°C and the reaction was continued for 2 hours. After separation, the modified polymethyl hydrogen siloxane was obtained.

[0065] S5: 30 g of the modified polymethylhydrogensiloxane obtained in step S4 was stirred and dissolved in 60 mL of xylene solvent, followed by the addition of 14 g of the diolefin biquinolinium compound obtained in step S3, 0.5 g of catalyst chloroplatinic acid, and 4.5 g of lithium bis(trifluoromethylsulfonyl)imide. The mixture was stirred and mixed uniformly at room temperature, placed in a vacuum oven, and heated to 105° C. for a cross-linking and curing reaction for 24 hours to obtain the polymer solid electrolyte.

[0066] Comparative Example 1

[0067] The raw material composition and preparation steps of the polymer solid electrolyte preparation method of this comparative example are basically the same as those of Example 1, except that, in the polymer solid electrolyte preparation method of this comparative example, triethylene glycol divinyl ether is not added for addition reaction in step S2.

[0068] Comparative Example 2

[0069] The raw material composition and preparation steps of the polymer solid electrolyte preparation method of this comparative example are basically the same as those of Example 1, except that, in the polymer solid electrolyte preparation method of this comparative example, 3-bromopropylene is not added in step S3 for the disubstitution reaction.

[0070] The polymer solid electrolytes prepared in Examples 1 to 5 and Comparative Examples 1 to 2 were subjected to performance tests, and the performance results are shown in Table 1:

[0071] Among them, the mechanical strength performance test method is: the example sample is cut into long strips with a length of 120 mm and a width of 15 mm. The mechanical strength of the polymer solid electrolyte is evaluated by a tensile test on a universal material testing machine, with tensile strength and elongation at break as evaluation indicators.

[0072] Ionic conductivity test method: Electrochemical impedance spectroscopy (EIS) was used to measure ionic conductivity.

[0073] Electrochemical stability window test method: Cyclic voltammetry (CV) is used to determine the electrochemical stability window of the electrolyte, that is, to measure the maximum voltage range that the electrolyte can withstand without decomposition.

[0074] Interface compatibility test method: The interface stability between the solid electrolyte and the electrode material is evaluated through battery cycle testing to evaluate the long-life performance of the solid electrolyte. Specifically, the solid electrolyte sample of the embodiment is first encapsulated into a solid-state battery with the positive electrode material lithium iron phosphate and the negative electrode material lithium titanate, and then the charge and discharge rate is set to C / 10 (the battery completes a full charge process within 10 hours). The voltage range is set to 1.0 to 5.0V, and the test is continued for 100 cycles. After 100 charge and discharge cycles, the capacity retention rate of the battery is used as an evaluation indicator.

[0075] Table 1

[0076] project Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Tensile strength, MPa 31.0 29.5 28.8 32.5 30.6 21.4 23.8 Elongation at break, % 13.4 12.3 12.6 14.1 13.2 8.5 10.3 <![CDATA[Ionic conductivity, 10 -4 S / cm]]> 3.1 2.9 3.0 3.2 3.1 2.2 1.2 Electrochemical stability window, V 5.2 5.0 5.1 5.3 5.1 4.9 4.5 Interface compatibility, % 91.7 90.8 89.5 92.1 91.7 85.2 88.1

[0077] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. Various changes and improvements are possible without departing from the spirit and scope of the present invention, and such changes and improvements fall within the scope of the invention as claimed.

Claims

1. A method for preparing a long-life wide electrochemical window polymer solid electrolyte, characterized in that: The preparation method comprises the following steps: S1: heating a quinoline compound and metallic sodium for a certain period of time, and obtaining a 4,4'-biquinoline intermediate after separation; S2: first subjecting the 4,4'-biquinoline intermediate obtained in step S1 to a mono-substitution reaction with a brominated alkane; then adding vinyl bromide to carry out a di-substitution reaction; then adding divinyl ether to carry out an addition reaction; and finally adding an aqueous solution containing a fluorine anion to carry out an anion exchange reaction to obtain a mono-olefin biquinolinium compound; S3: performing a disubstituted reaction of the 4,4'-biquinoline intermediate obtained in step S1 with a brominated olefin; then adding an aqueous solution containing a fluorine anion to perform an anion exchange reaction to obtain a diolefin biquinolinium compound; S4: dissolving a certain amount of polymethyl hydrogen siloxane in a solvent by heating and stirring, adding a mixture of the monoolefin biquinolinium compound obtained in step S2, a catalyst, and a solvent, and heating and reacting under inert atmosphere to obtain modified polymethyl hydrogen siloxane; S5: stirring and dissolving the modified polymethylhydrogensiloxane obtained in step S4 in a solvent, then adding the diolefin biquinolinium compound, catalyst, and lithium bis(trifluoromethylsulfonylimide) obtained in step S3, stirring and mixing at room temperature, placing in a vacuum oven, and heating for cross-linking and curing to obtain the polymer solid electrolyte; The mass ratio of the monoolefin biquinolinium compound to polymethylhydrogensiloxane is 10 to 15:1; The mass ratio of the diolefin biquinolinium compound to the modified polymethyl hydrogen siloxane is 2 to 3:

1.

2. The method for preparing a long-life wide electrochemical window polymer solid electrolyte according to claim 1, characterized in that: The quinoline compound is at least one of quinoline, 3-methylquinoline, 5-methylquinoline, 6-methylquinoline, 7-methylquinoline, 8-methylquinoline, 2,3-dimethylquinoline, 2,6-dimethylquinoline, 2,7-dimethylquinoline, 2,8-dimethylquinoline, 5,8-dimethylquinoline, 6,7-dimethylquinoline, 6,8-dimethylquinoline, 2,6,7-trimethylquinoline, 2,6,8-trimethylquinoline, 2,5,7-trimethylquinoline, 2,7,8-trimethylquinoline, and 2,5,8-trimethylquinoline.

3. The method for preparing a long-life wide electrochemical window polymer solid electrolyte according to claim 1, characterized in that: The brominated alkane is at least one of ethyl bromide, propyl bromide, butyl bromide and pentane bromide.

4. The method for preparing a long-life wide electrochemical window polymer solid electrolyte according to claim 1, characterized in that: The divinyl ether is at least one of ethylene glycol divinyl ether, diethylene glycol divinyl ether, and triethylene glycol divinyl ether.

5. The method for preparing a long-life wide electrochemical window polymer solid electrolyte according to claim 1, characterized in that: The fluorine-containing anion is at least one of tetrafluoroborate, trifluoromethanesulfonate, and hexafluorophosphate.

6. The method for preparing a long-life wide electrochemical window polymer solid electrolyte according to claim 1, characterized in that: The brominated olefin is at least one of 3-bromopropene, 3-bromo-2-methylpropene, 3-bromo-1-butene, 4-bromo-2-methyl-1-butene, 5-bromo-1-pentene, 5-bromo-1-hexene, and 6-bromo-1-hexene.

7. The method for preparing a long-life wide electrochemical window polymer solid electrolyte according to claim 1, characterized in that: The catalyst is at least one of chloroplatinic acid, palladium acetate and nickel acetate.

8. A long-life wide electrochemical window polymer solid electrolyte, characterized in that: The polymer solid electrolyte is prepared by the preparation method of the long-life and wide electrochemical window polymer solid electrolyte according to any one of claims 1 to 7.