Gel Polymer Electrolyte and Its Preparation Method and Application

Abstract

The present invention relates to the field of electrochemical energy storage technologies, and discloses a gel polymer electrolyte, a preparation method thereof, and an application thereof. The method includes: (1) performing a first mixing of alginate with an organic solvent to obtain a product I; (2) performing freeze-drying on the product I to obtain a product II; (3) performing a first contact of the product II with a cation source, where the cation source is a divalent cation source and / or a trivalent cation source, to obtain a product III; (4) performing a second contact of the product III with a lithium ion source to obtain a product IV; and (5) performing an adsorption treatment of the product IV on an electrolyte under an environment where H2O < 0.1 ppm and O2 < 0.1 ppm to obtain the gel polymer electrolyte. The gel polymer electrolyte provided by the present invention has a hierarchical pore structure, high mechanical strength, strong ionic conductivity, and more excellent electrochemical performance.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochemical energy storage, and particularly relates to a preparation method of a gel polymer electrolyte, the gel polymer electrolyte and its application. Background Art

[0002] Liquid lithium-ion batteries can no longer meet the growing energy storage demands, including from portable electronic products to renewable energy. In addition, the highly flammable liquid electrolyte and its potential leakage may lead to serious safety problems of the battery.

[0003] At present, solid electrolytes have become a key technology for high energy density and high safety requirements. Although solid electrolytes have more advantages such as excellent cycling performance, stable lithium stripping / plating performance, avoiding the generation of lithium dendrites and dead lithium compared with liquid electrolytes, problems such as low room temperature ionic conductivity and poor electrode interface contact have hindered the commercialization of solid-state batteries. Quasi-solid electrolytes combine the advantages of solid electrolytes and liquid electrolytes, and at the same time eliminate their existing disadvantages, becoming an effective solution to solve the above problems.

[0004] As a kind of quasi-solid electrolyte, the gel polymer electrolyte is composed of a polymer three-dimensional skeleton and a liquid electrolyte, and has advantages such as high ionic conductivity close to that of liquid electrolytes, low interfacial resistance, and easy preparation.

[0005] CN110299557A discloses a water-soluble polymer gel polymer electrolyte, its preparation method and application, specifically relating to the preparation of a water-soluble polymer material gel polymer electrolyte, and also including the application of such a gel polymer electrolyte in a primary or secondary electrochemical energy storage system. Such a gel polymer electrolyte is composed of a polymer membrane and a liquid electrolyte. The raw materials of the liquid electrolyte include a polymer or a mixture of the polymer and an inorganic filler. The gel polymer electrolyte provided by this prior art has the advantages of high conductivity, wide electrochemical window, and high lithium ion transference number. However, the gel polymer electrolyte prepared by this prior art has poor mechanical properties. Summary of the Invention

[0006] The object of the present invention is to provide a gel polymer electrolyte with a hierarchical pore structure, high mechanical strength, high ionic conductivity and excellent electrochemical performance.

[0007] To achieve the above object, on the one hand, the present invention provides a method for preparing a gel polymer electrolyte, which is characterized in that the method includes the following steps:

[0008] (1) First mix alginate with an organic solvent to obtain product I;

[0009] (2) Freeze-dry the product I to obtain product II;

[0010] (3) The product II is brought into first contact with a cation source to obtain product III, and the cation source is a divalent cation source and / or a trivalent cation source;

[0011] (4) The product III is brought into second contact with a lithium ion source to obtain product IV;

[0012] (5) Under the environment of H2O < 0.1 ppm and O2 < 0.1 ppm, the product IV is used to adsorb the electrolyte to obtain the gel polymer electrolyte.

[0013] Preferably, in step (1), the alginate is provided in the form of an aqueous alginate solution; the weight ratio of the alginate, the water, and the organic solvent is 1: 0.625 - 3.125: 0.059 - 0.59.

[0014] Preferably, the organic solvent is selected from at least one of epichlorohydrin, acetone, cyclohexane, and chloroform.

[0015] Preferably, in step (1), the conditions of the first mixing at least satisfy: the stirring speed is 100 - 1000 rpm, and the stirring time is 12 - 72 h.

[0016] Preferably, in step (2), the conditions of the freeze-drying at least satisfy: the temperature is -50 °C to -30 °C, the vacuum degree is 0.2 - 5 Pa, and the time is 12 - 48 h.

[0017] Preferably, in step (3), the cations in the cation source are selected from at least one of Ca 2+ , Ba 2+ , Co 2+ , Cu 2+ , Fe 2+ , Zn 2 + , Fe 3+ , Al 3+ .

[0018] Preferably, the time of the first contact is 2 - 24 h.

[0019] According to a preferred specific embodiment, the initial concentration of the cations in the system formed by the first contact is 20 - 120 mmol / L.

[0020] Preferably, in step (4), the lithium ions in the lithium ion source are provided by at least one of lithium hydroxide, lithium carbonate, and lithium oxide.

[0021] Preferably, the time of the second contact is 24 - 72 h.

[0022] According to another preferred specific embodiment, the initial concentration of lithium ions in the system formed by the second contact is the saturation concentration at 25 °C and 101 kPa.

[0023] Preferably, in step (5), the electrolyte contains a solvent and a solute, the solvent is an ester solvent and / or an ether solvent, and the solute is a lithium salt.

[0024] Preferably, the concentration of the solute in the electrolyte is 0.5 - 5 mol / L.

[0025] Preferably, in step (5), relative to 1 mm 3 of the product IV, the amount of the electrolyte used is 0.025 - 0.15 μL.

[0026] The second aspect of the present invention provides a gel polymer electrolyte prepared by the method described in the foregoing first aspect.

[0027] Preferably, the average thickness of the gel polymer electrolyte is 100 - 1000 μm, and the pore size range is 1 - 300 μm.

[0028] The third aspect of the present invention provides an application of the gel polymer electrolyte described in the foregoing second aspect in a battery electrochemical device.

[0029] Compared with the prior art, the technical solution provided by the present invention has at least the following advantages:

[0030] (1) The three-dimensional skeleton of the gel polymer electrolyte prepared by the method provided by the present invention has a hierarchical pore structure, which can significantly improve its electrolyte storage capacity, effectively avoid electrolyte leakage, and further improve the safety of the battery;

[0031] (2) The three-dimensional skeleton of the gel polymer electrolyte prepared by the method provided by the present invention has higher mechanical strength, which can effectively avoid the phenomenon of battery short circuit caused by lithium dendrites passing through the electrolyte;

[0032] (3) The gel polymer electrolyte prepared by the method provided by the present invention exhibits excellent cycle stability, low interfacial resistance, and high ionic conductivity, optimizes the solid electrolyte-electrode interface, and improves the electrochemical performance. Description of the Drawings

[0033] Figure 1 It is a scanning electron microscope image of the three-dimensional skeleton structure of the gel polymer. Detailed Embodiments

[0034] The endpoints and any values in the ranges disclosed herein are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed herein.

[0035] DMC: Dimethyl carbonate

[0036] DEC: Diethyl carbonate

[0037] EC: Ethylene carbonate

[0038] DOL: 1,3 - Dioxolane

[0039] DME: Dimethoxyethane

[0040] LiTFSI: Lithium bis(trifluoromethanesulfonyl)imide

[0041] As described above, the first aspect of the present invention provides a method for preparing a gel polymer electrolyte, characterized in that the method comprises the following steps:

[0042] (1) First mix the alginate with an organic solvent to obtain product I;

[0043] (2) Subject product I to freeze-drying to obtain product II;

[0044] (3) First contact product II with a cation source, to obtain product III, where the cation source is a divalent cation source and / or a trivalent cation source;

[0045] (4) Second contact product III with a lithium ion source to obtain product IV;

[0046] (5) Under an environment of H2O < 0.1 ppm and O2 < 0.1 ppm, subject product IV to an adsorption treatment with an electrolyte solution to obtain the gel polymer electrolyte.

[0047] Preferably, the alginate is selected from at least one of sodium alginate and potassium alginate.

[0048] Preferably, in step (1), the alginate is provided in the form of an alginate aqueous solution; the weight ratio of the alginate, the water, and the organic solvent is 1:0.625 - 3.125:0.059 - 0.59.

[0049] More preferably, the alginate is provided in the form of an aqueous alginate solution; the weight ratio of the alginate, the water, and the organic solvent is 1: 1.25 - 2.5: 0.236 - 0.354. The inventors of the present invention have found that under these preferred conditions, the gel polymer electrolyte of the present invention has a better hierarchical pore structure, higher mechanical strength, and more excellent ionic conductivity and electrochemical performance.

[0050] Preferably, the organic solvent is selected from at least one of epichlorohydrin, acetone, cyclohexane, and chloroform.

[0051] More preferably, the organic solvent is epichlorohydrin. The inventors of the present invention have found that under these preferred conditions, the gel polymer electrolyte of the present invention has a better hierarchical pore structure, higher mechanical strength, and more excellent ionic conductivity and electrochemical performance.

[0052] Preferably, in step (1), the conditions for the first mixing at least satisfy: the stirring speed is 100 - 1000 rpm, and the stirring time is 12 - 72 h.

[0053] More preferably, in step (1), the conditions for the first mixing at least satisfy: the stirring speed is 400 - 800 rpm, and the stirring time is 24 - 48 h. The inventors of the present invention have found that under these preferred conditions, the gel polymer electrolyte of the present invention has a better hierarchical pore structure, higher mechanical strength, and more excellent ionic conductivity and electrochemical performance.

[0054] Preferably, in step (2), the method includes: pouring the product I into a polytetrafluoroethylene or glassware such that the liquid level height of the product I in the ware is 1 - 4 mm, and then performing freeze-drying to obtain product II.

[0055] Preferably, in step (2), the conditions for the freeze-drying at least satisfy: the temperature is -50 °C to -30 °C, the vacuum degree is 0.2 - 5 Pa, and the time is 12 - 48 h.

[0056] Preferably, in step (3), the cation in the cation source is selected from Ca 2+ , Ba 2+ , Co 2+ , Cu 2+ , Fe 2+ , Zn 2 + , Fe 3+ , Al 3+ and at least one of them.

[0057] More preferably, the cation in the cation source is Ca 2+。The inventors of the present invention have found that under the preferred conditions, the gel polymer electrolyte described in the present invention has a better hierarchical pore structure, higher mechanical strength, and more excellent ionic conductivity and electrochemical performance.

[0058] Preferably, the time of the first contact is 2 - 24 h.

[0059] Preferably, the initial concentration of the cations in the system formed by the first contact is 20 - 120 mmol / L.

[0060] More preferably, the initial concentration of the cations in the system formed by the first contact is 40 - 100 mmol / L. The inventors of the present invention have found that under the preferred conditions, the gel polymer electrolyte described in the present invention has a better hierarchical pore structure, higher mechanical strength, and more excellent ionic conductivity and electrochemical performance.

[0061] Preferably, the cations of the present invention are provided in the form of an aqueous solution of a cation salt, and the present invention has no particular limitation on the solid - liquid weight ratio of the product II to the aqueous solution of the cation salt, as long as the aqueous solution of the cation salt can completely immerse the product II therein.

[0062] According to a preferred specific embodiment, the method in step (3) further includes:

[0063] After the first contact between the product II and the cation source, soak and wash repeatedly until the washing liquid does not contain the cations brought by alginate, and then dry at 30 - 50 °C for 12 - 24 h to obtain the product III.

[0064] Preferably, in step (4), the lithium ions in the lithium ion source are provided by at least one of lithium hydroxide, lithium carbonate, and lithium oxide.

[0065] Preferably, the time of the second contact is 24 - 72 h.

[0066] Preferably, the initial concentration of the lithium ions in the system formed by the second contact is the saturation concentration at 25 °C and 101 kPa.

[0067] Preferably, the lithium ions in the lithium ion source of the present invention are provided in the form of an aqueous solution of a lithium salt, and the present invention has no particular limitation on the solid - liquid weight ratio of the intermediate I to the aqueous solution of the lithium salt, as long as the aqueous solution of the lithium salt can completely immerse the intermediate I therein.

[0068] According to another preferred specific embodiment, the method in step (4) further includes:

[0069] After the second contact of the product III with the lithium ion source, it is repeatedly soaked and washed until the washing liquid does not contain the cations brought by alginate, and then dried at 30-50 °C for 12-36 h to obtain the product IV.

[0070] In the present invention, the fact that the washing liquid does not contain the cations brought by alginate means that the cations brought by alginate cannot be detected by X-ray diffraction analysis.

[0071] Preferably, in step (5), the electrolyte contains a solvent and a solute, the solvent is an ester solvent and / or an ether solvent, and the solute is a lithium salt.

[0072] More preferably, the ester solvent is selected from at least one of DMC, DEC, and EC.

[0073] More preferably, the ether solvent is selected from at least one of DOL and DME.

[0074] More preferably, the solute is selected from at least one of LiPF6, LiBF4, and LiTFSI.

[0075] Preferably, the concentration of the solute in the electrolyte is 0.5-5 mol / L.

[0076] Preferably, in step (5), relative to 1 mm 3 of the product IV, the amount of the electrolyte used is 0.025-0.15 μL.

[0077] The present invention has no particular limitation on the equipment for providing the environment of H2O < 0.1 ppm and O2 < 0.1 ppm, as long as the provided environment can meet the experimental production requirements. Those skilled in the art can select the equipment known in the art. Exemplarily, the equipment for providing the environment of H2O < 0.1 ppm and O2 < 0.1 ppm is a vacuum glove box. Those skilled in the art should not understand this as a limitation of the present invention.

[0078] As described above, the second aspect of the present invention provides a gel polymer electrolyte prepared by the method described in the first aspect above.

[0079] Preferably, the average thickness of the gel polymer electrolyte is 100-1000 μm, and the pore size range is 1-300 μm.

[0080] The gel polymer electrolyte has a three-dimensional gel polymer skeleton structure as Figure 1 shown. It can be seen from Figure 1 that the three-dimensional gel polymer skeleton has an obvious hierarchical pore structure, and the pores of different sizes are evenly distributed, laying a foundation for improving the storage capacity of the electrolyte and avoiding electrolyte leakage.

[0081] As described above, the third aspect of the present invention provides the application of the gel polymer electrolyte described in the second aspect above in a battery electrochemical device.

[0082] The present invention will be described in detail below by way of examples. In the following examples, unless otherwise specified, the raw materials are all commercially available products. In the following examples, the washing solution not containing sodium ions means that sodium ions cannot be detected in the washing solution by X-ray diffraction analysis.

[0083] Sodium alginate: purity 99.9%;

[0084] Electrolyte I: The solvent is a combination of DOL and DME, and the volume ratio is 1:1, and the solute is LiTFSI;

[0085] Electrolyte II: The solvent is a combination of DOL and DME, and the volume ratio is 1:1, and the solute is LiPF6;

[0086] Vacuum glove box: manufactured by MIKRONA Electromechanical Technology Co., Ltd., model super.

[0087] Preparation Example 1

[0088] (1) First mix the aqueous sodium alginate solution with epichlorohydrin to obtain Product I;

[0089] The amount of sodium alginate used is 30 g, and the weight ratio of the amounts of sodium alginate, water, and epichlorohydrin used is 1:2.5:0.295; the stirring speed of the first mixing is 600 rpm, and the stirring time is 36 h;

[0090] (2) Pour Product I into a polytetrafluoroethylene container, and then freeze-dry it at a temperature of -40 °C and a vacuum degree of 0.9 Pa for 24 h to obtain Product II;

[0091] (3) First contact Product II with an aqueous calcium chloride solution for 6 h, and then repeatedly soak and wash until no sodium ions are contained in the washing solution, and then dry it at 30 °C for 12 h to obtain Product III;

[0092] The calcium ion concentration in the aqueous calcium chloride solution is 60 mmol / L;

[0093] (4) Second contact Product III with an aqueous lithium hydroxide solution for 24 h, and then repeatedly soak and wash until no sodium ions are contained in the washing solution, and then dry it at 30 °C for 36 h to obtain Product IV;

[0094] The lithium ion concentration in the aqueous lithium hydroxide solution is the saturation concentration at 25 °C and 101 kPa;

[0095] (5) Under the environment of H2O < 0.1 ppm and O2 < 0.1 ppm in a vacuum glove box, the product IV is subjected to an adsorption treatment with the electrolyte I to obtain the gel polymer electrolyte;

[0096] The volume of the product IV is 1 mm 3 , the dosage of the electrolyte is 0.1 μL, and the concentration of the solute in the electrolyte I is 1 mol / L.

[0097] Preparation Example 2

[0098] (1) The sodium alginate aqueous solution and acetone are subjected to a first mixing to obtain the product I;

[0099] The dosage of sodium alginate is 20 g, and the weight ratio of the dosages of sodium alginate, water, and acetone is 1:1.25:0.236; the stirring speed of the first mixing is 400 rpm, and the stirring time is 24 h;

[0100] (2) The product I is poured into a polytetrafluoroethylene vessel, and then freeze-dried for 12 h under the conditions of a temperature of -50 °C and a vacuum degree of 0.2 Pa to obtain the product II;

[0101] (3) The product II is brought into first contact with the calcium chloride aqueous solution for 2 h, and then repeatedly soaked and washed until no sodium ions are contained in the washing liquid, and then dried at 40 °C for 18 h to obtain the product III;

[0102] The calcium ion concentration in the calcium chloride aqueous solution is 40 mmol / L;

[0103] (4) The product III is brought into second contact with the lithium carbonate aqueous solution for 48 h, and then repeatedly soaked and washed until no sodium ions are contained in the washing liquid, and then dried at 30 °C for 36 h to obtain the product IV;

[0104] The lithium ion concentration in the lithium hydroxide aqueous solution is the saturated concentration at 25 °C and 101 kPa;

[0105] (5) Under the environment of H2O < 0.1 ppm and O2 < 0.1 ppm in a vacuum glove box, the product IV is subjected to an adsorption treatment with the electrolyte I to obtain the gel polymer electrolyte;

[0106] The volume of the product IV is 1 mm 3 , the dosage of the electrolyte is 0.025 μL, and the concentration of the solute in the electrolyte I is 0.5 mol / L.

[0107] Preparation Example 3

[0108] (1) The sodium alginate aqueous solution and chloroform are subjected to a first mixing to obtain the product I;

[0109] The dosage of sodium alginate is 40 g, and the weight ratio of the dosages of sodium alginate, water, and chloroform is 1:2.5:0.354; the stirring speed of the first mixing is 800 rpm, and the stirring time is 48 h;

[0110] (2) Pour Product I into a polytetrafluoroethylene vessel, and then freeze-dry it for 48 h under the conditions of a temperature of -30°C and a vacuum degree of 5 Pa to obtain Product II;

[0111] (3) First contact Product II with an aqueous calcium chloride solution for 24 h, and then repeatedly soak and wash it until no sodium ions are contained in the washing liquid, and then dry it at 40°C for 18 h to obtain Product III;

[0112] The calcium ion concentration in the aqueous calcium chloride solution is 100 mmol / L;

[0113] (4) Second contact Product III with an aqueous lithium hydroxide solution for 72 h, and then repeatedly soak and wash it until no sodium ions are contained in the washing liquid, and then dry it at 30°C for 36 h to obtain Product IV;

[0114] The lithium ion concentration in the aqueous lithium hydroxide solution is the saturation concentration at 25°C and 101 kPa;

[0115] (5) Under the environment of a vacuum glove box with H2O < 0.1 ppm and O2 < 0.1 ppm, adsorb Product IV with Electrolyte I to obtain the gel polymer electrolyte;

[0116] The volume of Product IV is 1 mm 3 , the dosage of the electrolyte is 0.15 μL, and the concentration of the solute in Electrolyte II is 5 mol / L.

[0117] Preparation Example 4

[0118] This preparation example is carried out using a process similar to that of Preparation Example 1, the difference being that: in step (1), the weight ratio of the dosages of sodium alginate, water, and epichlorohydrin is 1:2.5:0.59.

[0119] The gel polymer electrolyte is prepared.

[0120] Preparation Example 5

[0121] This preparation example is carried out using a process similar to that of Preparation Example 1, the difference being that: in step (1), the conditions of the first mixing are: the stirring speed is 100 rpm, and the stirring time is 72 h.

[0122] The gel polymer electrolyte is prepared.

[0123] Preparation Example 6

[0124] This preparation example was carried out using a process similar to that of Preparation Example 1, except that: in step (3), the concentration of calcium ions in the calcium chloride aqueous solution was 20 mmol / L.

[0125] A gel polymer electrolyte was prepared.

[0126] Comparative Example 1

[0127] This comparative example was carried out using a process similar to that of Preparation Example 1, except that: in this comparative example, step (4) was not carried out, and the rest was the same as Preparation Example 1.

[0128] A gel polymer electrolyte was prepared.

[0129] Comparative Example 2

[0130] This comparative example was carried out using a process similar to that of Preparation Example 1, except that: in this comparative example, no organic solvent was used in step (1), that is:

[0131] (1) Sodium alginate and water were mixed for the first time to obtain an aqueous sodium alginate solution, which was product I;

[0132] The amount of sodium alginate used was 30 g, and the weight ratio of sodium alginate to water was 1:2.5; the stirring speed of the first mixing was 600 rpm, and the stirring time was 36 h.

[0133] A gel polymer electrolyte was prepared.

[0134] Test Example 1

[0135] The thickness of the gel polymer electrolyte was measured by the method of using a film thickness gauge (purchased from instrument, model CHY-CA);

[0136] The pore size range of the gel polymer electrolyte was measured by the method of BET specific surface area test.

[0137] The tensile strength of the gel polymer electrolyte was tested using a universal testing machine (Shimadzu EZ test); the gel polymer electrolyte was cut into a shape with a length of 30 mm and a width of 4 mm through a mold and installed in a universal tensile testing instrument equipped with a force sensor.

[0138] Table 1

[0139]

[0140] Test Example 2

[0141] The prepared gel polymer electrolyte and lithium foil were assembled into a lithium symmetric battery, that is, a Li / polymer electrolyte / Li lithium symmetric battery.

[0142] Then, the electrochemical performance, including the rate performance and cycling performance, was tested.

[0143] Rate performance test: The current densities were set to 0.2 mA cm -2 , 0.4 mA cm -2 , 0.6 mA cm -2 , 0.8 mA cm -2 , 1 mA cm -2 , 2 mA cm -2 . The results are shown in Table 2.

[0144] In the cycling performance test: Cycling was carried out at a current density of 0.2 mA cm -2 . The results are shown in Table 3.

[0145] Table 2

[0146]

[0147]

[0148] Table 3

[0149] Item Number of cycles at short circuit (cycles) Preparation Example 1 1500 Preparation Example 2 1462 Preparation Example 3 1411 Preparation Example 4 993 Preparation Example 5 945 Preparation Example 6 1038 Comparative Example 1 406 Comparative Example 2 657

[0150] From the above results, it can be seen that the gel polymer electrolyte prepared by the technical solution provided by the present invention has a better hierarchical pore structure, higher mechanical strength, and thus stronger liquid storage capacity and more excellent electrochemical performance.

[0151] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A method for preparing a gel polymer electrolyte, characterized in that, The method comprises the following steps: (1) First, mix alginate with an organic solvent to obtain Product I; (2) Then, subject Product I to freeze-drying to obtain Product II; (3) First, bring Product II into contact with a cation source, soak and wash it until the washing liquid no longer contains cations brought by alginate, to obtain Product III, where the cation source is a divalent cation source and / or a trivalent cation source; (4) Then, bring Product III into contact with a lithium ion source, soak and wash it until the washing liquid no longer contains cations brought by alginate, to obtain Product IV; (5) Under the environment of H2O < 0.1 ppm and O2 < 0.1 ppm, subject Product IV to adsorption treatment on an electrolyte to obtain the gel polymer electrolyte.

2. The method according to claim 1, wherein In step (1), the alginate is provided in the form of an alginate aqueous solution; the weight ratio of the amounts of the alginate, the water, and the organic solvent is 1: 0.625 - 3.125: 0.059 - 0.59; and / or, The organic solvent is selected from at least one of epichlorohydrin, acetone, cyclohexane, and chloroform.

3. The method according to claim 1 or 2, characterized in that, In step (1), the conditions for the first mixing at least satisfy: the stirring speed is 100 - 1000 rpm, and the stirring time is 12 - 72 h.

4. The method according to claim 1 or 2, characterized in that, In step (2), the conditions for the freeze-drying at least satisfy: the temperature is -50°C to -30°C, the vacuum degree is 0.2 - 5 Pa, and the time is 12 - 48 h.

5. The method according to claim 1 or 2, characterized in that, In step (3), the cation in the cation source is selected from at least one of Ca 2+ , Ba 2+ , Co 2+ , Cu 2+ , Fe 2+ , Zn 2+ , Fe 3+ , Al 3+ ; and / or, The time for the first contact is 2 - 24 h; and / or, The initial concentration of cations in the system formed by the first contact is 20 - 120 mmol / L.

6. The method according to claim 1 or 2, characterized in that In step (4), the lithium ions in the lithium ion source are provided by at least one of lithium hydroxide, lithium carbonate, and lithium oxide; and / or, The time for the second contact is 24 - 72 h; and / or, The initial concentration of lithium ions in the system formed by the second contact is the saturation concentration at 25°C and 101 kPa.

7. The method according to claim 1 or 2, characterized in that, In step (5), the electrolyte contains a solvent and a solute, the solvent is an ester solvent and / or an ether solvent, and the solute is a lithium salt; and / or, The concentration of the solute in the electrolyte is 0.5 - 5 mol / L.

8. The method according to claim 1 or 2, characterized in that In step (5), relative to 1 mm 3 of the product IV, the amount of the electrolyte used is 0.025 - 0.15 μL.

9. A gel polymer electrolyte prepared by the method according to any one of claims 1 - 8.

10. The gel polymer electrolyte according to claim 9, characterized in that, The average thickness of the gel polymer electrolyte is 100 - 1000 μm, and the pore size range is 1 - 300 μm.

11. Application of the gel polymer electrolyte according to claim 9 or 10 in a battery electrochemical device.

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