Preparation method and application of wide-temperature-range lithium battery gel electrolyte

Abstract

The invention discloses a preparation method and application of a wide-temperature-range lithium battery gel electrolyte, and belongs to the technical field of lithium battery gel electrolytes. Comprising the following steps: in an argon atmosphere, adding a cyclic ether functional monomer into a weighing bottle, and then adding an additive with the mass fraction of 10-30% of the cyclic ether functional monomer to obtain a mixed solution; adding a lithium salt as an initiator into the mixed solution to obtain a polymer electrolyte precursor solution; and injecting the polymer electrolyte precursor solution into two sides of the diaphragm, packaging the button cell, transferring the button cell into a drying oven at 60-80 DEG C to promote monomer polymerization, and initiating cyclic ether functional monomer copolymerization in the precursor solution by an initiator to finally obtain the in-situ polymerized gel electrolyte. According to the preparation method disclosed by the invention, the performance bottleneck of a traditional linear polyether electrolyte is broken through through cyclic ether monomer copolymerization, the ionic conductivity and the voltage window of the gel electrolyte are effectively improved, the safety performance of the battery is remarkably improved, and the cycling stability under a wide temperature range working condition is widened.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of lithium battery gel electrolyte, and particularly relates to a preparation method and application of a lithium battery gel electrolyte with a wide temperature range. BACKGROUND

[0002] Polymer lithium metal batteries face many challenges in practical applications, including uncontrollable lithium dendrite growth, interface side reactions, and large volume changes of the negative electrode during the cycle process. Polyether electrolyte materials have excellent toughness and good interface contact and are highly concerned.

[0003] At present, polyether electrolytes obtained by in-situ process can effectively fill the gap between the electrode / electrolyte interface and the electrode material. For example, the Chinese invention patent with the title of gel electrolyte containing LiPF-6 and DOL and its preparation method and application, application publication number CN202211563554.3, discloses that 1,3-dioxolane (DOL) is one of the popular monomers for in-situ preparation of gel electrolyte materials. The ring-opening polymerization reaction can be easily initiated by Lewis salt (such as LiPF6 and (CF3SO3)Al) under mild conditions, so as to realize the close contact of the interface and the efficient conduction of ions. However, polyether electrolyte materials have inherent defects, such as low ionic conductivity, low oxidation voltage window, and narrow available temperature range, which limit their practical application.

[0004] Therefore, it is urgent to design a lithium battery gel electrolyte with wide temperature range and stable cycle to improve its ionic conductivity and oxidation voltage window, so as to broaden the application scenarios under wide temperature range working conditions. SUMMARY

[0005] The purpose of the present application is to solve the problems of low ionic conductivity, low oxidation voltage window, and narrow available temperature range of existing polyether electrolyte materials, and to provide a preparation method and application of a lithium battery gel electrolyte with a wide temperature range. By copolymerizing cyclic ether monomers, the performance bottleneck of traditional linear polyether electrolytes is broken, the ionic conductivity and voltage window of the gel electrolyte can be improved at the same time, the gel electrolyte has good ability to inhibit dendrite growth, the safety performance of the battery is significantly improved, and the cycle stability under wide temperature range working conditions is widened.

[0006] To achieve the above purpose, the following technical scheme is adopted in the present application: a preparation method of a lithium battery gel electrolyte with a wide temperature range, comprising the following steps: S1, in an argon atmosphere, a cyclic ether functional monomer is added to a weighing bottle, an additive with a mass fraction of 10% to 30% of the cyclic ether functional monomer is added, and magnetic stirring is performed for 1h to obtain a mixed solution; The cyclic ether functional monomer is obtained by mixing any one of 1,3,5-trioxane and 1,3-dioxolane, 1,4-dioxane, and tetrahydrofuran, and the additive is any one of ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, and diethylene glycol dibutyl ether. S2, under an argon atmosphere, a lithium salt is added to the mixed solution obtained in step S1 as an initiator, and magnetic stirring is performed for 1h to obtain a polymer electrolyte precursor solution; The lithium salt is any two combinations of lithium hexafluorophosphate, lithium bisfluorosulfonylimide, lithium bis(trifluoromethanesulfonyl)imide, and lithium bis(oxalato)borate, and the concentration of the lithium salt in the cyclic ether monomer is 1-4 mol / L. S3, under an argon atmosphere, a coin cell is assembled, the polymer electrolyte precursor solution obtained in step S2 is injected into both sides of a separator, and the coin cell is packaged, the coin cell is transferred to an oven at 60-80 DEG C to promote polymerization of the monomer, the initiator initiates copolymerization of the cyclic ether functional monomer in the precursor solution, and finally an in-situ polymerized gel electrolyte is obtained.

[0007] In the step S1, the cyclic ether functional monomer is a mixture of two cyclic ether monomers with equal mass.

[0008] In the step S2, the initiator is a mixture of two lithium salts with equal molar mass.

[0009] In the step S3, the coin cell is transferred to an oven at 60-80 DEG C, and the standing time is 1-3h.

[0010] The application further discloses application of the gel electrolyte prepared by the preparation method in preparation of a lithium ion battery.

[0011] The positive electrode material of the lithium ion battery is at least one of LiFePO4 (LFP), LiNi 0.8 Co 0.1 Mn 0.1 O2 (NCM811), LiNi 0.9 Co 0.05 Mn 0.05 O2 (NCM9055), and LiCoO2 (LCO); the negative electrode material is at least one of a silicon-carbon negative electrode and lithium metal; and the separator is at least one of a polypropylene film, a polypropylene-polyethylene-polypropylene film, and a cellulose film.

[0012] The application has the following beneficial effects: 1) The preparation method of the present application uses two cyclic ethers as functional monomers, and a complex salt system as an initiator and ion conductor to initiate the copolymerization of the cyclic ether monomers in the battery shell; the performance bottleneck of traditional linear polyether electrolytes can be broken through by copolymerization of cyclic ether monomers, while the ionic conductivity and voltage window of the gel electrolyte are improved, and stable long cycle in a wide temperature range of-30℃ to 100℃ is realized, which widens the cycle stability in a wide temperature range.

[0013] 2) The preparation method of the present application is convenient and efficient, and the preparation raw materials used are industrial bulk chemicals, which are widely available and low in price; the crystalline-amorphous phase can be balanced by copolymerization of functional monomers, realizing the consideration of high ionic conductivity and mechanical strength, enhancing the interface stability, inhibiting the growth of lithium dendrites, and the highest occupied molecular orbital (HOMO) energy value of the functional monomer can give the copolymer strong oxidation resistance, which can effectively match the high-nickel positive electrode.

[0014] 3) The oxidation voltage window of traditional linear polyether PDOL is 4.3V, and the ionic conductivity at-30℃ is only 0.05mS cm -1 , which seriously limits its wide temperature range applicability; the present application effectively improves the oxidation voltage window to 5.1V by in-situ copolymerization of two cyclic ether monomers, and the ionic conductivity at-30℃ reaches 0.15mS cm -1 . BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 The infrared spectrum of the gel electrolyte prepared in Example 1 of the present application is shown in the figure; Figure 2 The discharge specific capacity graph at-30℃ when the LFP positive electrode is matched by Example 1 and Example 7 of the present application at 0.5C for 1000 cycles is shown in the figure; Figure 3 The discharge specific capacity graph at 100℃ when the LFP positive electrode is matched by Example 1 and Example 7 of the present application at 0.3C for 200 cycles is shown in the figure; Figure 4 The discharge specific capacity graph at 30℃ when the NCM9055 positive electrode is matched by Example 1 and Example 7 of the present application at 1C and 4.5V for 300 cycles is shown in the figure. DETAILED DESCRIPTION

[0016] The present application will be further explained and described below in conjunction with the drawings and specific examples.

[0017] Example 1: The present application provides a preparation method of a wide temperature range lithium battery gel electrolyte, comprising the following steps: S1, under argon atmosphere, equal mass of 1,3,5-trioxane and 1,3-dioxolane were added into a weighing bottle, an additive ethylene glycol dibutyl ether was introduced, the additive amount was 20% of the mass of the cyclic ether monomer, and magnetic stirring was performed for 1h; S2, under argon atmosphere, equal molar lithium bis(oxalato)borate and lithium bis(fluorosulfonyl)imide were introduced as initiators into the mixed solution obtained in step S1, the concentration of lithium salt in the cyclic ether monomer was 2.5 mol / L, magnetic stirring was performed for 1h, and a polymer electrolyte precursor solution was obtained; S3, under argon atmosphere, a button cell was assembled, the polymer electrolyte precursor solution obtained in step S2 was injected into both sides of the separator and the button cell was packaged, the button cell was transferred to a 60℃ oven to promote monomer polymerization, the standing time was 2h, the initiator initiated the copolymerization of the functional monomers in the precursor solution, and finally an in-situ polymerized gel electrolyte was obtained.

[0018] Example 2: The present application provides a preparation method of a wide-temperature-range lithium battery gel electrolyte, comprising the following steps: S1, under argon atmosphere, equal mass of 1,3,5-trioxane and 1,3-dioxolane were added into a weighing bottle, an additive ethylene glycol dibutyl ether was introduced, the additive amount was 20% of the mass of the cyclic ether monomer, and magnetic stirring was performed for 1h; S2, under argon atmosphere, equal molar lithium bis(oxalato)borate and lithium bis(fluorosulfonyl)imide were introduced as initiators into the mixed solution obtained in step S1, the concentration of lithium salt in the cyclic ether monomer was 2.5 mol / L, magnetic stirring was performed for 1h, and a polymer electrolyte precursor solution was obtained; S3, under argon atmosphere, a button cell was assembled, the polymer electrolyte precursor solution obtained in step S2 was injected into both sides of the separator and the button cell was packaged, the button cell was transferred to a 60℃ oven to promote monomer polymerization, the standing time was 2h, the initiator initiated the copolymerization of the functional monomers in the precursor solution, and finally an in-situ polymerized gel electrolyte was obtained.

[0019] Example 3: The present application provides a preparation method of a wide-temperature-range lithium battery gel electrolyte, comprising the following steps: S1, under argon atmosphere, equal mass of 1,3,5-trioxane and 1,3-dioxolane were added into a weighing bottle, an additive ethylene glycol dibutyl ether was introduced, the additive amount was 20% of the mass of the cyclic ether monomer, and magnetic stirring was performed for 1h; S2, under argon atmosphere, equal molar lithium bis(oxalato)borate and lithium bis(fluorosulfonyl)imide were introduced as initiators into the mixed solution obtained in step S1, the concentration of lithium salt in the cyclic ether monomer was 2.5 mol / L, magnetic stirring was performed for 1h, and a polymer electrolyte precursor solution was obtained; S3, in an argon atmosphere, assemble the button cell, inject the polymer electrolyte precursor solution obtained in step S2 into both sides of the diaphragm and package the button cell, place the button cell in a 70℃ oven to promote monomer polymerization, the standing time is 3h, the initiator initiates the copolymerization of the cyclic ether functional monomer in the precursor solution, and a in-situ polymerized gel electrolyte is obtained.

[0020] Embodiment 4: The present application provides a preparation method of a wide-temperature-range lithium battery gel electrolyte, comprising the following steps: S1, in an argon atmosphere, add equal amounts of 1,3,5-trioxane and 1,3-dioxolane into a weighing bottle, introduce an additive ethylene glycol dimethyl ether, the additive amount is 30% of the mass of the cyclic ether monomer, and magnetically stir for 1h; S2, in an argon atmosphere, introduce equal molar amounts of lithium bis (oxalate) borate and lithium bis (fluorosulfonyl) imide as initiators into the mixed solution obtained in step S1, the concentration of lithium salt in the cyclic ether monomer is 2.5mol / L, magnetically stir for 1h, and a polymer electrolyte precursor solution is obtained; S3, in an argon atmosphere, assemble the button cell, inject the polymer electrolyte precursor solution obtained in step S2 into both sides of the diaphragm and package the button cell, place the button cell in a 70℃ oven to promote monomer polymerization, the standing time is 3h, the initiator initiates the copolymerization of the cyclic ether functional monomer in the precursor solution, and a in-situ polymerized gel electrolyte is obtained.

[0021] Embodiment 5: The present application provides a preparation method of a wide-temperature-range lithium battery gel electrolyte, comprising the following steps: S1, in an argon atmosphere, add equal amounts of 1,3,5-trioxane and 1,3-dioxolane into a weighing bottle, introduce an additive ethylene glycol dimethyl ether, the additive amount is 30% of the mass of the cyclic ether monomer, and magnetically stir for 1h;

[0022] S2, in an argon atmosphere, introduce equal molar amounts of lithium bis (oxalate) borate and lithium bis (fluorosulfonyl) imide as initiators into the mixed solution obtained in step S1, the concentration of lithium salt in the cyclic ether monomer is 2.5mol / L, magnetically stir for 1h, and a polymer electrolyte precursor solution is obtained; S3, in an argon atmosphere, assemble the button cell, inject the polymer electrolyte precursor solution obtained in step S2 into both sides of the diaphragm and package the button cell, place the button cell in a 70℃ oven to promote monomer polymerization, the standing time is 3h, the initiator initiates the copolymerization of the cyclic ether functional monomer in the precursor solution, and a in-situ polymerized gel electrolyte is obtained.

[0023] Embodiment 6: The present application provides a preparation method of a wide-temperature-range lithium battery gel electrolyte, comprising the following steps: S1, under argon atmosphere, equal mass of 1,3,5-trioxane and 1,3-dioxolane were added into a weighing bottle, an additive diethylene glycol dibutyl ether was introduced, the additive amount was 10% of the mass of the cyclic ether monomer, and magnetic stirring was performed for 1 h.

[0024] S2, under argon atmosphere, equal molar lithium bis (oxalate) borate and lithium bis (fluorosulfonyl) imide were introduced as initiators into the mixed solution obtained in step S1, the concentration of lithium salt in the cyclic ether monomer was 2.5 mol / L, magnetic stirring was performed for 1 h, and a polymer electrolyte precursor solution was obtained; S3, under argon atmosphere, a button cell was assembled. The polymer electrolyte precursor solution obtained in step S2 was injected into both sides of the separator and the button cell was packaged. The button cell was transferred to a 60℃ oven to promote monomer polymerization, and the standing time was 2 h. The initiator initiated the copolymerization of the cyclic ether functional monomer in the precursor solution to obtain an in-situ polymerized gel electrolyte.

[0025] Example 7: The present application provides a preparation method of a wide-temperature-range lithium battery gel electrolyte, comprising the following steps: S1, under argon atmosphere, equal mass of 1,3,5-trioxane and 1,3-dioxolane were added into a weighing bottle, an additive diethylene glycol dibutyl ether was introduced, the additive amount was 20% of the mass of the cyclic ether monomer, and magnetic stirring was performed for 1 h; S2, under argon atmosphere, equal molar lithium bis (oxalate) borate and lithium hexafluorophosphate were introduced as initiators into the mixed solution obtained in step S1, the concentration of lithium salt in the cyclic ether monomer was 1 mol / L, magnetic stirring was performed for 1 h, and a polymer electrolyte precursor solution was obtained; S3, under argon atmosphere, a button cell was assembled. The polymer electrolyte precursor solution obtained in step S2 was injected into both sides of the separator and the button cell was packaged. The button cell was transferred to a 60℃ oven to promote monomer polymerization, and the standing time was 2 h. The initiator initiated the copolymerization of the cyclic ether functional monomer in the precursor solution to obtain an in-situ polymerized gel electrolyte.

[0026] Example 8: The present application provides a preparation method of a wide-temperature-range lithium battery gel electrolyte, comprising the following steps: S1, under argon atmosphere, equal mass of 1,3,5-trioxane and 1,3-dioxolane were added into a weighing bottle, an additive diethylene glycol dibutyl ether was introduced, the additive amount was 20% of the mass of the cyclic ether monomer, and magnetic stirring was performed for 1 h; S2. Under argon atmosphere, equal molar lithium bis (oxalate) borate and lithium bis (trifluoromethanesulfonyl) imide were introduced as initiators into the mixed solution obtained in step S1, the concentration of lithium salt in the cyclic ether monomer was 4 mol / L, magnetic stirring was performed for 1 h, and a polymer electrolyte precursor solution was obtained; S3. Assemble the button cell in an argon atmosphere, inject the polymer electrolyte precursor solution obtained in step S2 into both sides of the separator and seal the button cell, and transfer the button cell to a 60°C oven to promote polymerization of the monomers, and let stand for 2 h to initiate copolymerization of the cyclic ether functional monomers in the precursor solution to obtain a gel electrolyte polymerized in situ.

[0027] Comparative Example 1: The same as the preparation process of Example 1, except that no 1,3,5-trioxane monomer was added in Comparative Example 1.

[0028] Comparative Example 2: The same as the preparation process of Example 1, except that no functional additive ethylene glycol dibutyl ether was added in Comparative Example 2.

[0029] Comparative Example 3: The same as the preparation process of Example 1, except that no lithium bis(oxalato)borate was added in Comparative Example 3.

[0030] As shown in FIG. 1, compared with the DOL+TXE monomer, the shift of the double-peak absorption peak and the vibration characteristic peak of the long chain of Example 1 (P(DOL+TXE)) indicate that the DOL+TXE monomer forms a gel electrolyte by copolymerization, and the product contains the structure after copolymerization. Figure 1 Test 1: -30°C ionic conductivity and room temperature electrochemical window of the gel electrolyte prepared in situ in the battery shell of each example and comparative example, and the statistical results are shown in Table 1 below:

[0031] Table 1 As shown in Table 1, in combination with the analysis of the oxidation voltage window and the -30°C ionic conductivity, Example 1 has the best comprehensive performance (5.1 V, 0.15 mS cm -1 ), and the results of Comparative Examples 1-3 cannot guarantee good comprehensive performance. After ring-opening copolymerization of the monomers of Example 2, the high HOMO value of tetrahydrofuran reduces the oxidation stability of the copolymer, and thus the voltage window is low.

[0032] Example 3 has a very low ring tension of 1,4-dioxane, lacks thermodynamic driving force, and is not easy to undergo ring-opening polymerization; after standing for 3 h at 25°C, the degree of polymerization of the ether mixed solution is low, the oxidation resistance is poor, and the ionic conductivity is high at low temperature.

[0033] Example 4 has a high content of ethylene glycol dimethyl ether, which effectively improves the ion transport kinetics in the electrolyte body phase at low temperature, but also reduces the oxidation resistance of the copolymer.

[0034] ​

[0035] Example 5 has a lower solvent content, which limits ion transport in the electrolyte bulk phase at low temperatures, thereby reducing the ionic conductivity.

[0036] Increasing the alkyl chain length of the ether solvent in Example 6 can effectively enhance its oxidation resistance and reduce the oxidative decomposition at the positive electrode interface.

[0037] In Example 7, lithium hexafluorophosphate can hydrolyze to initiate monomer copolymerization, and its inherent high-pressure instability reduces the oxidation resistance of the electrolyte; a low content of lithium salt further reduces the inorganic content at the electrode interface, leading to severe side reactions at the electrode interface.

[0038] In Example 8, high salt content significantly improves interface stability and effectively promotes monomer polymerization, and the copolymer has high oxidation stability; however, the high salt content of the electrolyte increases the viscosity, and the cations and anions are prone to form aggregated ion pairs, reducing the ion transport kinetics at low temperatures.

[0039] Compared with Example 1, Comparative Example 1 lacks 1,3,5-trioxane monomer, and the polymer has poor oxidation resistance.

[0040] Compared with Example 1, Comparative Example 2 lacks ethylene glycol dibutyl ether, and there are no liquid microzones in the copolymer, reducing the ion transport performance.

[0041] Compared with Example 1, Comparative Example 3 lacks lithium difluoro(oxalato)borate, and the inorganic content at the electrode interface is low, and the side reactions at the interface are intensified.

[0042] According to the experimental results of Examples 1-7, by adjusting the types of monomers, lithium salt content, additive types, and polymerization time, all examples exhibit better oxidation voltage window and low-temperature ionic conductivity than single linear polyether. The oxidation voltage window of traditional linear polyether PDOL is 4.3 V, and the ionic conductivity at -30°C is only 0.05 mS cm -1 This indicates that the above modification methods can compensate for the inherent shortcomings of DOL-based electrolytes, effectively improving their application in gel-state batteries.

[0043] Performance measurement experiment 2: Select the gel electrolytes prepared from Example 1 and Example 7 with better and worse comprehensive performance of oxidation voltage window and ionic conductivity, and measure the cycle performance at -30°C to 100°C.

[0044] Figure 2 To match the LFP positive electrode, at -30°C, the cycle performance results at 0.5C, Example 1 can stably cycle 1000 times, showing excellent ion dynamics at low temperatures; Example 7 loses 37 mAh g -1 of discharge specific capacity when cycled at 0.5C for 100 cycles, and the capacity decay is severe at low temperatures.

[0045] Figure 3 To match the LFP positive electrode, at 100℃, the cycle performance results at 0.3C, example 1 can be stably cycled for 200 cycles, showing excellent thermal stability of the copolymer at high temperature; the cycle stability of example 7 at high temperature is poor, which may be related to the high temperature self-decomposition of lithium hexafluorophosphate.

[0046] Figure 4 To match the NCM9055 positive electrode, at 30℃, 1C, 4.5V, the cycle performance results, example 1 has a capacity retention rate of 80% after 210 cycles, showing excellent oxidation stability; example 7 has the same initial specific discharge capacity (189.7 mAh g -1 ) as example 1, but under the same test conditions, the specific discharge capacity of example 7 is only 167.8 mAh g -1 after 30 cycles, indicating that the electrolyte structure has been degraded at high voltage, resulting in irreversible capacity loss.

[0047] From the above test results of example 7, although the test performance is lower than that of example 1, it can still maintain a certain cycle performance at -30℃~100℃, so the cycle stability of all examples can be guaranteed to be applicable in a wide temperature range of -30℃~100℃.

[0048] The oxidation voltage window and -30℃ ion conductivity of the gel electrolyte prepared by the method described in the application are significantly improved, the functional monomer, additive, and lithium salt system are coupled, the amorphous phase content of the polymer is effectively improved by copolymerization, the ion complexing ability is improved, and the oxidation stability of the ether oxygen group in the molecular chain is also effectively improved, thereby enhancing the high-voltage cycle stability of the battery.

[0049] The above description is only to illustrate the technical solutions of the present application and not to limit, other modifications or equivalent replacements to the technical solutions of the present application made by those skilled in the art should be covered in the scope of the claims of the present application as long as they do not deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. A method for preparing a wide temperature range lithium battery gel electrolyte, characterized in that: The preparation method comprises the following steps: S1, under an argon atmosphere, a cyclic ether functional monomer is added into a weighing bottle, an additive with a mass fraction of 10-30% of the cyclic ether functional monomer is added, and magnetic stirring is performed for 1 h to obtain a mixed solution; The cyclic ether functional monomer is obtained by mixing 1,3,5-trioxane with any one of 1,3-dioxolane, 1,4-dioxane and tetrahydrofuran, and the additive is any one of ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether and diethylene glycol dibutyl ether; S2, under an argon atmosphere, a lithium salt is added into the mixed solution obtained in step S1 as an initiator, and magnetic stirring is performed for 1 h to obtain a polymer electrolyte precursor solution; The lithium salt is any two combinations of lithium hexafluorophosphate, lithium bisfluorosulfonylimide, lithium bis(trifluoromethanesulfonyl)imide and lithium bis(oxalato)borate, and the concentration of the lithium salt in the cyclic ether monomer is 1-4 mol / L; S3, under an argon atmosphere, a button cell is assembled, the polymer electrolyte precursor solution obtained in step S2 is injected into both sides of a diaphragm, and the button cell is packaged, the button cell is transferred to an oven at 60-80°C to promote monomer polymerization, the initiator initiates copolymerization of the cyclic ether functional monomer in the precursor solution, and finally an in-situ polymerized gel electrolyte is obtained. 2.The method for preparing a wide-temperature-range lithium battery gel electrolyte according to claim 1, characterized by: In step S1, the cyclic ether functional monomer is a mixture of two cyclic ether monomers with equal mass.

3. The method according to claim 1, wherein the method is characterized by: In step S2, the initiator is a mixture of two lithium salts with equal molar mass. 4.The method of claim 1, wherein the gel electrolyte is prepared by the following steps: (1) dissolving the lithium salt in the solvent to form a solution; (2) adding the polymer into the solution to form a mixture; (3) adding the additive into the mixture to form a gel electrolyte. In step S3, the button cell is transferred to an oven at 60-80°C, and the standing time is 1-3 h.

5. Application of the gel electrolyte prepared by the preparation method in any one of claims 1-4 in the preparation of a lithium ion battery.

6. Use according to claim 5, characterized in that: The positive material of the lithium ion battery is at least one of LiFePO4 (LFP), LiNi 0.8 Co 0.1 Mn 0.1 O2 (NCM811), LiNi 0.9 Co 0.05 Mn 0.05 O2 (NCM9055), LiCoO2 (LCO); the negative material is at least one of silicon-carbon negative electrode and lithium metal; and the separator is at least one of polypropylene film, polypropylene-polyethylene-polypropylene film and cellulose film.

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