Preparation method of composite gel polymer electrolyte with high ionic conductivity

Abstract

The invention relates to the technical field of gel polymer electrolytes, and discloses a preparation method of a high-ionic-conductivity composite gel polymer electrolyte, which comprises the following steps: preparing a composite polymer film by using a surface-modified ZSM-5 molecular sieve, a polymer matrix and a plasticizer as raw materials, swelling and activating the composite polymer film through a liquid electrolyte, and preparing the high-ionic-conductivity composite gel polymer electrolyte. The composite gel polymer electrolyte is obtained. The composite gel polymer electrolyte obtained by the preparation method of the high-ionic-conductivity composite gel polymer electrolyte has high ionic conductivity, the interface stability between an electrode and the electrolyte is improved, and the cycle capacity and the cycle stability of a lithium battery are finally improved; wherein the surface of ZSM-5 contains Lewis acid sites which are beneficial to dissociation and transmission of lithium ions, in addition, ZSM-5 has a special two-dimensional channel structure which allows the lithium ions to enter and can limit passing of PF6-1, so that the transference number of the lithium ions can be increased, and PEG can weaken the intermolecular acting force of PVDF and inhibit crystallization of PVDF, so that the ionic conductivity is effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of gel polymer electrolytes, in particular to a method for preparing a composite gel polymer electrolyte with high ionic conductivity. Background Art

[0002] Gel polymer electrolytes (GPEs) have attracted widespread attention for their application in lithium batteries due to their high ionic conductivity of liquid electrolytes and the excellent safety performance of solid electrolytes. A typical gel polymer electrolyte consists of a polymer matrix, a lithium salt, and an organic solvent. Currently, the most studied matrices include polyvinylidene fluoride (PVDF), polyethylene oxide (PEO), polyacrylonitrile (PAN), and polymethyl methacrylate (PMMA). PVDF, due to its high dielectric constant (8.3), exhibits excellent dissociation ability towards lithium salts. However, PVDF is a semi-crystalline substance at room temperature, resulting in low ionic conductivity, which limits its practical application.

[0003] Introducing inorganic fillers is one of the most commonly used strategies to improve the ionic conductivity of GPEs. Inorganic fillers can generally be divided into two categories: one is active fillers that can conduct lithium ions (such as Li 1.3 Al 0.3 Ti 1.7 (PO4)3、Li7La3Zr2O 12 、Li 10 GeP2S 12 etc.), the other type is inert fillers that do not participate in the conduction of lithium ions (such as Al2O3, TiO2, SiO2, ZSM-5, etc.). Although active fillers can additionally transport lithium ions, many active fillers are electrochemically unstable with lithium metal negative electrodes and are unstable in the air. They need to be coated or surface modified before use. However, incorporating inert fillers into the polymer matrix can not only disrupt the movement of polymer chain segments and reduce the crystallinity of the polymer, but also the surface of the inert filler contains rich functional groups that can react with lithium salts to produce Lewis acid-base reactions, promote the dissociation of lithium salts, and thus improve the lithium ion transport capacity. However, due to the poor interfacial compatibility between inorganic fillers and organic polymers, the fillers are usually unevenly dispersed, resulting in insufficient addition effect. Therefore, surface modification has become an effective strategy to improve the uneven dispersion of fillers in polymers. By grafting organic functional groups on the surface of the filler, the inorganic / organic interface compatibility can be effectively improved and the dispersion of the filler in the organic polymer can be improved.

[0004] However, the introduction of inorganic fillers alone cannot enable GPEs to obtain ideal ionic conductivity. Previous studies have shown that plasticizers help the dissociation of ion pairs, weaken the intermolecular forces of polymers, increase the amorphous region of polymers, and improve the flexibility of polymers, thereby improving the ionic conductivity of GPEs and enhancing their stability. Low ionic conductivity is still the main reason limiting the practical application of GPEs. Therefore, choosing a suitable plasticizer is an effective way to improve ionic conductivity. Summary of the Invention

[0005] The object of the present invention is to provide a method for preparing a high ionic conductivity composite gel polymer electrolyte to solve the problem of poor cycle stability of existing gel polymer electrolytes in lithium battery applications mentioned in the above background art.

[0006] To achieve the above object, the present invention provides the following technical solution: a method for preparing a composite gel polymer electrolyte with high ionic conductivity, comprising the following steps: Step A: preparing a composite polymer membrane using surface-modified ZSM-5 molecular sieve, a polymer matrix and a plasticizer as raw materials; Step B: The composite polymer membrane is swollen and activated by a liquid electrolyte to obtain a composite gel polymer electrolyte.

[0007] As a preferred technical solution of the present invention, in step A, the steps of preparing a composite polymer membrane using the surface-modified ZSM-5 molecular sieve, polymer matrix and plasticizer as raw materials are as follows: Step A1: dissolving the polymer matrix and the plasticizer in a solvent and stirring to uniformly dissolve them to obtain a first mixed solution; Step A2: dispersing the surface-modified ZSM-5 molecular sieve in a solvent by ultrasonication to obtain a second mixed solution; Step A3: The first mixed liquid and the second mixed liquid are stirred and mixed, poured into a mold and dried to obtain a composite polymer film.

[0008] As a preferred technical solution of the present invention, in step A1, the mass ratio of the polymer matrix to the plasticizer is 1:(0.2-0.8); the mass ratio of the polymer matrix to the solvent is 1:(10-20); the stirring time is 8-10 hours; and the solvent is N-methylpyrrolidone.

[0009] As a preferred technical solution of the present invention, in step A2, the mass ratio of the surface-modified ZSM-5 molecular sieve to the solvent is (0.0075-0.0225):1; the ultrasonic dispersion time is 10-90 min; and the solvent is N-methylpyrrolidone.

[0010] As a preferred technical solution of the present invention, in step A3, the first mixed liquid and the second mixed liquid are mixed at 60-80° C. and stirred for 6-24 hours, then poured into a polytetrafluoroethylene plate and dried at 40-60° C. to obtain a composite polymer film.

[0011] As a preferred technical solution of the present invention, in step A, the preparation method of the surface-modified ZSM-5 is: ZSM-5 and 3-(isomethylacryloyloxy)propyltrimethoxysilane were ultrasonically dispersed in ethanol, and then surface-modified ZSM-5 was obtained after stirring, centrifugation, washing and drying. The dispersion is to disperse 1 g of ZSM-5 in a mixed solution of 1 mL of 3-(isomethacryloyloxy)propyltrimethoxysilane and 19 mL of anhydrous ethanol, and the dispersion method is ultrasonication for 5 minutes; The stirring is carried out at 30° C. for 48 hours; the centrifugation time is 2 minutes and the rotation speed is 8000 r / min; and the washing is carried out three times with anhydrous ethanol.

[0012] As a preferred technical solution of the present invention, in step B, the step of swelling and activating the composite polymer membrane with a liquid electrolyte is: The composite polymer membrane is immersed in an electrolyte and allowed to stand for 3 hours to allow the composite polymer membrane to fully swell and activate, thereby obtaining a composite gel polymer electrolyte; Wherein, the amount of the liquid electrolyte is 5 to 8 mL; The liquid electrolyte is a lithium hexafluorophosphate electrolyte; the lithium hexafluorophosphate electrolyte is formed by mixing 1M lithium hexafluorophosphate, ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate solutions; and the volume ratio of the ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate is 1:1:1.

[0013] Wherein, the polymer matrix includes one or more of polyvinylidene fluoride (PVDF), polyethylene oxide (PEO), polyacrylonitrile (PAN), and polymethyl methacrylate (PMMA); The plasticizer includes one or more of polyethylene glycol (PEG), ionic liquid, propylene carbonate (PC), ethylene carbonate (EC), and polyvinyl chloride (PVC).

[0014] Compared with the prior art, the present invention has the following advantages: the preparation method of the high ionic conductivity composite gel polymer electrolyte adopts PVDF as the polymer matrix, surface-modified ZSM-5 as the filler, and PEG as the plasticizer to prepare a composite polymer membrane, which is then swollen and activated by the electrolyte to obtain a composite gel polymer electrolyte, wherein ZSM-5 as aluminosilicate has abundant Lewis acid sites on the surface, which is conducive to the dissociation and transmission of lithium ions. In addition, ZSM-5 has a special two-dimensional channel structure, which allows lithium ions to enter while limiting PF6 -1 The passage of PEG can increase the lithium ion migration number. The use of PEG as a plasticizer can weaken the intermolecular force of PVDF and inhibit PVDF crystallization, thereby effectively improving the ionic conductivity. The composite gel polymer electrolyte prepared by the above method in the present invention has high ionic conductivity, improves the interface stability between the electrode and the electrolyte, and ultimately improves the cycle capacity and cycle stability of the lithium battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 1 is a scanning electron microscope (SEM) image of the composite polymer film in the embodiment of the present invention; wherein a is embodiment 1, and b is embodiment 2; Figure 2 This is the XRD of the composite polymer film of Example 1 of the present invention; Figure 3 The chronoamperometric curve and the AC impedance spectrum before and after polarization (inset) and the lithium ion transference number ( ); Figure 4 This is a graph showing the long cycle performance of a lithium iron phosphate battery using a composite gel polymer electrolyte according to Example 1 of the present invention; Figure 5 This is a comparison diagram of the impedance before and after long-term cycling of the composite gel polymer electrolyte of Example 1 of the present invention; Figure 6 ion conductivity of the composite gel polymer electrolyte of each embodiment of the present invention at room temperature. DETAILED DESCRIPTION

[0016] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0017] See also Figure 1 - Figure 6, the technical solution of the present invention: a method for preparing a high ionic conductivity composite gel polymer electrolyte: Example

[0018] A method for preparing a high ionic conductivity composite gel polymer electrolyte comprises the following steps: 1 g of ZSM-5 was dispersed in a mixed solution of 1 mL of 3-(isomethylacryloyloxy)propyltrimethoxysilane and 19 mL of anhydrous ethanol. After being fully dispersed by ultrasonication for 5 minutes, the mixture was stirred at 30°C for 48 hours, washed three times with anhydrous ethanol by centrifugation, and then dried at 100°C for 24 hours to obtain surface-modified ZSM-5. Weigh 1g of PVDF and dissolve it in 14g of NMP, then weigh PEG at a mass ratio of PVDF to PEG of 1:0.6 and add it to the above solution, stir evenly to obtain a first mixed solution; weigh surface-modified ZSM-5 at a mass ratio of surface-modified ZSM-5 to solvent of 0.0125:1, and ultrasonicate for 40 minutes to evenly disperse the surface-modified ZSM-5 in 4g of NMP to obtain a second mixed solution; pour the second mixed solution into the first mixed solution, stir evenly, and then transfer it to an oil bath, stir at 60°C for 12h to obtain a homogeneous viscous slurry, pour the slurry into a polytetrafluoroethylene plate, dry it in a forced air oven at 60°C for 3h, and then transfer it to a vacuum oven, keep it at 60°C and dry it for 6h to obtain a composite polymer membrane.

[0019] The composite polymer membrane was immersed in 6-8 mL of lithium hexafluorophosphate electrolyte and swelled and activated for 3 h to obtain a composite gel polymer electrolyte. Example

[0020] A method for preparing a high ionic conductivity composite gel polymer electrolyte comprises the following steps: 1 g of ZSM-5 was dispersed in a mixed solution of 1 mL of 3-(isomethylacryloyloxy)propyltrimethoxysilane and 19 mL of anhydrous ethanol. After being fully dispersed by ultrasonication for 5 minutes, the mixture was stirred at 30°C for 48 hours, washed three times with anhydrous ethanol by centrifugation, and then dried at 100°C for 24 hours to obtain surface-modified ZSM-5. Weigh 1g of PVDF and dissolve it in 14g of NMP, then weigh PEG at a mass ratio of PVDF to PEG of 1:0.8 and add it to the above solution, stir evenly to obtain a first mixed solution; weigh surface-modified ZSM-5 at a mass ratio of surface-modified ZSM-5 to solvent of 0.0125:1, and ultrasonicate for 40 minutes to evenly disperse the surface-modified ZSM-5 in 4g of NMP to obtain a second mixed solution; pour the second mixed solution into the first mixed solution, stir evenly, and then transfer it to an oil bath pot, stir at 60°C for 12h to obtain a homogeneous viscous slurry; pour the slurry onto a polytetrafluoroethylene plate, dry it in a forced air oven at 60°C for 3h, then transfer it to a vacuum oven, keep it at 60°C and dry it for 6h to obtain a composite polymer membrane.

[0021] The composite polymer membrane was immersed in 6 to 8 mL of lithium hexafluorophosphate electrolyte and swelled and activated for 3 hours to obtain a composite gel polymer electrolyte. Example

[0022] A method for preparing a high ionic conductivity composite gel polymer electrolyte comprises the following steps: 1 g of ZSM-5 was dispersed in a mixed solution of 1 mL of 3-(isomethylacryloyloxy)propyltrimethoxysilane and 19 mL of anhydrous ethanol. After being fully dispersed by ultrasonication for 5 minutes, the mixture was stirred at 30°C for 48 hours, washed three times with anhydrous ethanol by centrifugation, and then dried at 100°C for 24 hours to obtain surface-modified ZSM-5. Weigh 1g of PEO and dissolve it in 14g of NMP, then weigh PEG at a mass ratio of PEO to PEG of 1:0.4 and add it to the above solution, stir evenly to obtain a first mixed solution; weigh surface-modified ZSM-5 at a mass ratio of surface-modified ZSM-5 to solvent of 0.0125:1, and ultrasonicate for 40 minutes to evenly disperse the surface-modified ZSM-5 in 4g of NMP to obtain a second mixed solution; pour the second mixed solution into the first mixed solution, stir evenly, and then transfer it to an oil bath pot, stir at 60°C for 12h to obtain a homogeneous viscous slurry; pour the slurry onto a polytetrafluoroethylene plate, dry it in a forced air oven at 60°C for 3h, then transfer it to a vacuum oven, keep it at 60°C and dry it for 6h to obtain a composite polymer membrane.

[0023] The composite polymer membrane was immersed in 6 to 8 mL of lithium hexafluorophosphate electrolyte and swelled and activated for 3 hours to obtain a composite gel polymer electrolyte. Example

[0024] A method for preparing a high ionic conductivity composite gel polymer electrolyte comprises the following steps: 1 g of ZSM-5 was dispersed in a mixed solution of 1 mL of 3-(isomethylacryloyloxy)propyltrimethoxysilane and 19 mL of anhydrous ethanol. After being fully dispersed by ultrasonication for 5 minutes, the mixture was stirred at 30°C for 48 hours, washed three times with anhydrous ethanol by centrifugation, and then dried at 100°C for 24 hours to obtain surface-modified ZSM-5. Weigh 1g of PAN and dissolve it in 14g of NMP, then weigh PC at a mass ratio of PAN to PC of 1:0.2 and add it to the above solution, stir evenly to obtain a first mixed solution; weigh surface-modified ZSM-5 at a mass ratio of surface-modified ZSM-5 to solvent of 0.0125:1, and ultrasonicate for 40 minutes to evenly disperse the surface-modified ZSM-5 in 4g of NMP to obtain a second mixed solution; pour the second mixed solution into the first mixed solution, stir evenly, and then transfer it to an oil bath pot, stir at 60°C for 12h to obtain a homogeneous viscous slurry; pour the slurry onto a polytetrafluoroethylene plate, dry it in a forced air oven at 60°C for 3h, then transfer it to a vacuum oven, keep it at 60°C and dry it for 6h to obtain a composite polymer membrane.

[0025] The composite polymer membrane was immersed in 6 to 8 mL of lithium hexafluorophosphate electrolyte and swelled and activated for 3 hours to obtain a composite gel polymer electrolyte. Example

[0026] A method for preparing a high ionic conductivity composite gel polymer electrolyte comprises the following steps: 1 g of ZSM-5 was dispersed in a mixed solution of 1 mL of 3-(isomethylacryloyloxy)propyltrimethoxysilane and 19 mL of anhydrous ethanol. After being fully dispersed by ultrasonication for 5 minutes, the mixture was stirred at 30°C for 48 hours, washed three times with anhydrous ethanol by centrifugation, and then dried at 100°C for 24 hours to obtain surface-modified ZSM-5. Weigh 1g of PMMA and dissolve it in 14g of NMP, then weigh EC at a mass ratio of PMMA to EC of 1:0.6 and add it to the above solution, stir evenly to obtain a first mixed solution; weigh surface-modified ZSM-5 at a mass ratio of surface-modified ZSM-5 to solvent of 0.0125:1, and ultrasonicate for 40 minutes to evenly disperse the surface-modified ZSM-5 in 4g of NMP to obtain a second mixed solution; pour the second mixed solution into the first mixed solution, stir evenly, and then transfer it to an oil bath pot, stir at 60°C for 12h to obtain a homogeneous viscous slurry; pour the slurry onto a polytetrafluoroethylene plate, dry it in a forced air oven at 60°C for 3h, then transfer it to a vacuum oven, keep it at 60°C and dry it for 6h to obtain a composite polymer membrane.

[0027] The composite polymer membrane was immersed in 6 to 8 mL of lithium hexafluorophosphate electrolyte and swelled and activated for 3 hours to obtain a composite gel polymer electrolyte. Example

[0028] A method for preparing a high ionic conductivity composite gel polymer electrolyte comprises the following steps: 1 g of ZSM-5 was dispersed in a mixed solution of 1 mL of 3-(isomethylacryloyloxy)propyltrimethoxysilane and 19 mL of anhydrous ethanol. After being fully dispersed by ultrasonication for 5 minutes, the mixture was stirred at 30°C for 48 hours, washed three times with anhydrous ethanol by centrifugation, and then dried at 100°C for 24 hours to obtain surface-modified ZSM-5. Weigh 1g of PVDF and dissolve it in 14g of NMP, then weigh EC at a mass ratio of PVDF to EC of 1:0.6 and add it to the above solution, stir evenly to obtain a first mixed solution; weigh surface-modified ZSM-5 at a mass ratio of surface-modified ZSM-5 to solvent of 0.0125:1, and ultrasonicate for 40 minutes to evenly disperse the surface-modified ZSM-5 in 4g of NMP to obtain a second mixed solution; pour the second mixed solution into the first mixed solution, stir evenly, and then transfer it to an oil bath pot, stir at 60°C for 12h to obtain a homogeneous viscous slurry; pour the slurry onto a polytetrafluoroethylene plate, dry it in a forced air oven at 60°C for 3h, then transfer it to a vacuum oven, keep it at 60°C and dry it for 6h to obtain a composite polymer membrane.

[0029] The composite polymer membrane was immersed in 6-8 mL of lithium hexafluorophosphate electrolyte and swelled and activated for 3 h to obtain a composite gel polymer electrolyte. Example

[0030] A method for preparing a high ionic conductivity composite gel polymer electrolyte comprises the following steps: 1 g of ZSM-5 was dispersed in a mixed solution of 1 mL of 3-(isomethylacryloyloxy)propyltrimethoxysilane and 19 mL of anhydrous ethanol. After being fully dispersed by ultrasonication for 5 minutes, the mixture was stirred at 30°C for 48 hours, washed three times with anhydrous ethanol by centrifugation, and then dried at 100°C for 24 hours to obtain surface-modified ZSM-5. Weigh 1g of PVDF and dissolve it in 14g of NMP, then weigh PC at a mass ratio of PVDF to PC of 1:0.6 and add it to the above solution, stir evenly to obtain a first mixed solution; weigh surface-modified ZSM-5 at a mass ratio of surface-modified ZSM-5 to solvent of 0.0125:1, and ultrasonicate for 40 minutes to evenly disperse the surface-modified ZSM-5 in 4g of NMP to obtain a second mixed solution; pour the second mixed solution into the first mixed solution, stir evenly, and then transfer it to an oil bath pot, stir at 60°C for 12h to obtain a homogeneous viscous slurry; pour the slurry onto a polytetrafluoroethylene plate, dry it in a forced air oven at 60°C for 3h, then transfer it to a vacuum oven, keep it at 60°C and bake it for 6h to obtain a composite polymer membrane.

[0031] The composite polymer membrane was immersed in 6-8 mL of lithium hexafluorophosphate electrolyte and swelled and activated for 3 h to obtain a composite gel polymer electrolyte. Example

[0032] A method for preparing a high ionic conductivity composite gel polymer electrolyte comprises the following steps: 1 g of ZSM-5 was dispersed in a mixed solution of 1 mL of 3-(isomethylacryloyloxy)propyltrimethoxysilane and 19 mL of anhydrous ethanol. After being fully dispersed by ultrasonication for 5 minutes, the mixture was stirred at 30°C for 48 hours, washed three times with anhydrous ethanol by centrifugation, and then dried at 100°C for 24 hours to obtain surface-modified ZSM-5. Weigh 1g of PEO and dissolve it in 14g of NMP, then weigh EC at a mass ratio of PEO to EC of 1:0.6 and add it to the above solution, stir evenly to obtain a first mixed solution; weigh surface-modified ZSM-5 at a mass ratio of surface-modified ZSM-5 to solvent of 0.0075:1, and ultrasonicate for 40 minutes to evenly disperse the surface-modified ZSM-5 in 4g of NMP to obtain a second mixed solution; pour the second mixed solution into the first mixed solution, stir evenly, and then transfer it to an oil bath pot, stir at 60°C for 12h to obtain a homogeneous viscous slurry; pour the slurry onto a polytetrafluoroethylene plate, dry it in a forced air oven at 60°C for 3h, then transfer it to a vacuum oven, keep drying at 60°C for h, and obtain a composite polymer membrane.

[0033] The composite polymer membrane was immersed in 6-8 mL of lithium hexafluorophosphate electrolyte and swelled and activated for 3 h to obtain a composite gel polymer electrolyte. Example

[0034] A method for preparing a high ionic conductivity composite gel polymer electrolyte comprises the following steps: 1 g of ZSM-5 was dispersed in a mixed solution of 1 mL of 3-(isomethylacryloyloxy)propyltrimethoxysilane and 19 mL of anhydrous ethanol. After being fully dispersed by ultrasonication for 5 minutes, the mixture was stirred at 30°C for 48 hours, washed three times with anhydrous ethanol by centrifugation, and then dried at 100°C for 24 hours to obtain surface-modified ZSM-5. Weigh 1g of PMMA and dissolve it in 14g of NMP, then weigh PVC at a mass ratio of PMMA to PVC of 1:0.6 and add it to the above solution, stir evenly to obtain a first mixed solution; weigh surface-modified ZSM-5 at a mass ratio of surface-modified ZSM-5 to solvent of 0.0175:1, and ultrasonicate for 40 minutes to evenly disperse the surface-modified ZSM-5 in 4g of NMP to obtain a second mixed solution; pour the second mixed solution into the first mixed solution, stir evenly, and then transfer it to an oil bath, stir at 60°C for 12h to obtain a homogeneous viscous slurry; pour the slurry onto a polytetrafluoroethylene plate, dry it in a forced air oven at 60°C for 3h, then transfer it to a vacuum oven, keep it at 60°C and dry it for 6h to obtain a composite polymer membrane.

[0035] The composite polymer membrane was immersed in 6-8 mL of lithium hexafluorophosphate electrolyte and swelled and activated for 3 h to obtain a composite gel polymer electrolyte. Example

[0036] A method for preparing a high ionic conductivity composite gel polymer electrolyte comprises the following steps: 1 g of ZSM-5 was dispersed in a mixed solution of 1 mL of 3-(isomethylacryloyloxy)propyltrimethoxysilane and 19 mL of anhydrous ethanol. After being fully dispersed by ultrasonication for 5 minutes, the mixture was stirred at 30°C for 48 hours, washed three times with anhydrous ethanol by centrifugation, and then dried at 100°C for 24 hours to obtain surface-modified ZSM-5. Weigh 1g of PVDF and dissolve it in 14g of NMP, then weigh PVC at a mass ratio of PVDF to PVC of 1:0.6 and add it to the above solution, stir evenly to obtain a first mixed solution; weigh surface-modified ZSM-5 at a mass ratio of surface-modified ZSM-5 to solvent of 0.0225:1, and ultrasonicate for 40 minutes to evenly disperse the surface-modified ZSM-5 in 4g of NMP to obtain a second mixed solution; pour the second mixed solution into the first mixed solution, stir evenly, and then transfer it to an oil bath, stir at 60°C for 12h to obtain a homogeneous viscous slurry; pour the slurry onto a polytetrafluoroethylene plate, dry it in a forced air oven at 60°C for 3h, then transfer it to a vacuum oven, keep it at 60°C and dry it for 6h to obtain a composite polymer membrane.

[0037] The composite polymer membrane was immersed in 6-8 mL of lithium hexafluorophosphate electrolyte and swelled and activated for 3 h to obtain a composite gel polymer electrolyte.

[0038] The contents not described in detail in this specification belong to the prior art known to those skilled in the art.

[0039] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a high ionic conductivity composite gel polymer electrolyte, characterized in that: The following steps are involved: Step A: preparing a composite polymer membrane using surface-modified ZSM-5 molecular sieve, a polymer matrix and a plasticizer as raw materials; Step B: The composite polymer membrane is swollen and activated by a liquid electrolyte to obtain a composite gel polymer electrolyte.

2. The method for preparing a high ionic conductivity composite gel polymer electrolyte according to claim 1, characterized in that: In step A, the steps of preparing a composite polymer membrane using the surface-modified ZSM-5 molecular sieve, polymer matrix and plasticizer as raw materials are as follows: Step A1: dissolving the polymer matrix and the plasticizer in a solvent and stirring to uniformly dissolve them to obtain a first mixed solution; Step A2: dispersing the surface-modified ZSM-5 molecular sieve in a solvent by ultrasonication to obtain a second mixed solution; Step A3: The first mixed liquid and the second mixed liquid are stirred and mixed, poured into a mold and dried to obtain a composite polymer film.

3. The method for preparing a high ionic conductivity composite gel polymer electrolyte according to claim 2, characterized in that: In the step A1, the mass ratio of the polymer matrix to the plasticizer is 1:(0.2-0.8); the mass ratio of the polymer matrix to the solvent is 1:(10-20); the stirring time is 8-10 hours; and the solvent is N-methylpyrrolidone.

4. The method for preparing a high ionic conductivity composite gel polymer electrolyte according to claim 2, characterized in that: In step A2, the mass ratio of the surface-modified ZSM-5 molecular sieve to the solvent is (0.0075-0.0225):1; the ultrasonic dispersion time is 10-90 minutes; and the solvent is N-methylpyrrolidone.

5. The method for preparing a high ionic conductivity composite gel polymer electrolyte according to claim 2, characterized in that: In the step A3, the first mixed solution and the second mixed solution are mixed at 60-80° C. and stirred for 6-24 hours, then poured into a polytetrafluoroethylene plate and dried at 40-60° C. to obtain a composite polymer membrane.

6. The method for preparing a high ionic conductivity composite gel polymer electrolyte according to claim 1, characterized in that: In step A, the preparation method of surface-modified ZSM-5 is: ZSM-5 and 3-(isomethylacryloyloxy)propyltrimethoxysilane were ultrasonically dispersed in ethanol, and then surface-modified ZSM-5 was obtained after stirring, centrifugation, washing and drying. The dispersion is to disperse 1 g of ZSM-5 in a mixed solution of 1 mL of 3-(isomethacryloyloxy)propyltrimethoxysilane and 19 mL of anhydrous ethanol, and the dispersion method is ultrasonication for 5 minutes; The stirring is carried out at 30° C. for 48 hours; the centrifugation time is 2 minutes and the rotation speed is 8000 r / min; and the washing is carried out three times with anhydrous ethanol.

7. The method for preparing a high ionic conductivity composite gel polymer electrolyte according to claim 1, characterized in that: In step B, the step of subjecting the composite polymer membrane to swelling and activation by a liquid electrolyte is as follows: immersing the composite polymer membrane in the electrolyte and allowing it to stand for 3 hours to allow the composite polymer membrane to fully swell and activate, thereby obtaining a composite gel polymer electrolyte; Wherein, the amount of the liquid electrolyte is 5 to 8 mL; Wherein, the liquid electrolyte is lithium hexafluorophosphate electrolyte; the lithium hexafluorophosphate electrolyte is prepared by mixing 1M lithium hexafluorophosphate, ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate solution; the volume ratio of ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate is 1:1:1, Wherein, the polymer matrix includes one or more of polyvinylidene fluoride (PVDF), polyethylene oxide (PEO), polyacrylonitrile (PAN), and polymethyl methacrylate (PMMA); The plasticizer includes one or more of polyethylene glycol (PEG), ionic liquid, propylene carbonate (PC), ethylene carbonate (EC), and polyvinyl chloride (PVC).

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