A solid electrolyte based on ionic liquid and preparation method thereof

Abstract

The present invention provides a solid electrolyte based on ionic liquid and a preparation method thereof, belonging to the technical field of solid electrolytes. The solid electrolyte of the present invention is composed of the following components by mass: 100 parts of electrolyte matrix; 0-20 parts of plasticizer; 5-50 parts of lithium salt; 0-30 parts of organic framework material. The weight of the solid electrolyte of the present invention decreases by less than 1.0% when heated to 150°C, and decreases by 3.6% when heated to 300°C, which is higher than the thermal stability requirement of the solid electrolyte.

Description

Technical Field

[0001] The present invention relates to the technical field of solid electrolytes, and in particular to a solid electrolyte based on ionic liquids and a preparation method thereof. Background Art

[0002] With the development of science and technology, batteries are being used more and more widely, especially in the fields of electric vehicles and energy storage systems, and the performance requirements for batteries are becoming higher and higher. Traditional liquid batteries can no longer meet the needs of modern society due to safety hazards such as leakage and flammability, as well as low energy density. Therefore, solid-state batteries have become a research hotspot in the battery field due to their advantages such as high safety and high energy density.

[0003] A. Existing inorganic solid electrolytes have problems such as large interface resistance between inorganic solid electrolytes and electrodes, easy separation after multiple cycles, and insufficient flexibility. B. Organic polymer electrolytes, due to the generally high glass transition temperature of polymers, will lead to weaker movement of polymer segments, slow ion migration, low conductivity, and poor resistance to high voltage. In addition, the polymer itself has not completely solved the essential problem of safety and non-combustion.

[0004] In order to improve the conductivity of the electrolyte and the mobility of lithium ions, ionic liquids are used in combination with inorganic solid electrolytes. This can improve the ion mobility of the electrolyte, but there is still a defect of insufficient flexibility. In order to improve flexibility, organic polymers such as PEO and PVDF are generally used in combination with inorganic solid electrolytes to improve flexibility, but there are defects such as large internal resistance of the battery, low ionic conductivity, and intolerance to high voltage.

[0005] Therefore, how to obtain a solid electrolyte that can improve both the flexibility of the electrolyte and the ionic conductivity and its preparation method are technical problems that need to be solved at present. Summary of the invention

[0006] The object of the present invention is to provide a solid electrolyte based on ionic liquid and a preparation method thereof, so as to solve the above-mentioned technical problems.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] The present invention provides a solid electrolyte based on ionic liquid, comprising the following components in parts by weight:

[0009]

[0010]

[0011] The electrolyte matrix comprises a solid ionic liquid and a polymer;

[0012] The polymer comprises a polyionic liquid and one or more of polyethylene oxide, poly-1,3-dioxolane, polyvinyl ethylene carbonate, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer and polyacrylonitrile.

[0013] Furthermore, the mass ratio of the solid ionic liquid to the polymer is 10-90:90-10.

[0014] Further, the solid ionic liquid comprises 1,3-dimethylimidazolium bisfluorosulfonyl imide salt, N,N-dimethylpyrrolidine bistrifluoromethylsulfonyl imide salt, N,N-dimethylpyrrolidine tetrafluoroborate, N-methyl-N-ethylpyrrolidine bisfluorosulfonyl imide salt, N-methyl-N-ethylpyrrolidine bistrifluoromethylsulfonyl imide salt, N,N-dimethylpiperidinium bisfluorosulfonyl imide salt, N,N-dimethylpiperidinium bistrifluoromethylsulfonyl imide salt, N-ethyl-N-methylpiperidinium One or more of bisfluorosulfonyl imide salt, N-ethyl-N-methylpiperidinium bistrifluoromethylsulfonyl imide salt, tetramethylammonium bisfluorosulfonyl imide salt, dimethyldiethylammonium bistrifluoromethylsulfonyl imide salt, 1,1-spirobipyrrolidine bisfluorosulfonyl imide salt, 1,1-spirobipyrrolidine tetrafluoroborate, tetraethylammonium tetrafluoroborate, tetraethylammonium hexafluorophosphate, tetrabutylammonium bistrifluoromethylsulfonyl imide salt and tetrabutylammonium bisfluorosulfonyl imide salt.

[0015] Further, the polyionic liquid comprises poly 1-vinyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide salt, poly 1-vinyl-3-methylimidazolium bis(fluorosulfonyl)imide salt, poly 1-vinyl-3-ethylimidazolium hexafluorophosphate salt, poly 1-vinyl-3-ethylimidazolium bis(fluorosulfonyl)imide salt, poly-1-vinyl-3-ethylimidazolium bis(trifluoromethyl)sulfonyl imide salt, poly-1-vinyl-3-butylimidazolium bis(trifluoromethyl)sulfonyl imide salt, poly-1-vinyl-3-butylimidazolium bis(fluorosulfonyl)imide salt, poly 1-allyl-3-methylimidazolium methyl sulfate salt, poly 1-allyl-3-methylimidazolium tetrafluoroborate, poly 1-allyl-3-methylimidazolium bis(trifluoromethyl)sulfonyl imide salt, poly-1-vinyl-3- One or more of allyl imidazole bis(trifluoromethyl)sulfonyl imide salt, poly 1-vinyl-3-allylimidazole tetrafluoroborate, poly 1-vinyl-3-allylimidazole hexafluorophosphate, poly-1-vinyl-3-benzylimidazole bis(trifluoromethyl)sulfonyl imide salt, poly dimethylallylammonium bis(trifluoromethyl)sulfonyl imide salt, poly dimethyldiallylammonium bis(trifluoromethyl)sulfonyl imide salt, poly 1-(4-allylbenzyl)-3-ethylimidazole bis(trifluoromethyl)sulfonyl imide salt, poly 1-(epoxypropyl)-3-methylimidazole bis(trifluoromethyl)sulfonyl imide salt, poly 1-(epoxypropyl)-3-methylimidazole bis(trifluoromethyl)sulfonyl imide salt, and poly 3-butyl-1-(2-(methacryloyloxy)ethyl)imidazole bis(trifluoromethyl)sulfonyl imide salt.

[0016] Further, the plasticizer comprises one or more of liquid ionic liquid, polyethylene glycol, trioxymethylene, succinonitrile and 1,2-dimethoxyethane;

[0017] The lithium salt comprises one or more of lithium bis(oxalatoborate), lithium difluorooxalatoborate, lithium bis(trifluoromethanesulfonylimide), lithium bis(fluorosulfonylimide), lithium hexafluorophosphate, lithium perchlorate and lithium tetrafluoroborate.

[0018] Furthermore, the liquid ionic liquid is compounded from one or more ionic liquids composed of the following anions and cations:

[0019] The cation comprises 1-ethyl-3-methylimidazolium cation, 1-propyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation, 1-ethylmethoxy-3-methylimidazolium cation, 1-ethyl-3-methylpyrrolidinium cation, 1-propyl-3-methylpyrrolidinium cation, 1-butyl-3-methylpyrrolidinium cation, 1-ethylmethoxy-3-methylpyrrolidinium cation, N-ethyl-N-methylpiperidinium cation, N-propyl-N-methylpiperidinium cation, N-butyl-N-methylpiperidinium cation or N-ethylmethoxy-N-methylpiperidinium cation;

[0020] The anion comprises bis(fluorosulfonyl)imide, bis(trifluoromethanesulfonyl)imide, hexafluorophosphoric acid, bis(oxalyl)boric acid, trifluoromethanesulfonic acid, tetrafluoroboric acid or perchloric acid.

[0021] Furthermore, the organic framework material comprises one or more of ZIF-67, ZIF-8, TpPa-SO3Li, DMTHA-Si-Li, TAPT-DMTP and TAPT-DVA.

[0022] The present invention provides a method for preparing a solid electrolyte based on an ionic liquid, comprising the following steps:

[0023] 1) mixing a solid ionic liquid, a polymer, a lithium salt, a plasticizer and an organic framework material in an organic solvent, and dissolving or dispersing them uniformly to obtain a mixed solution;

[0024] 2) The mixed solution is poured into a mold to evaporate the organic solvent, and finally the mixture is dried under vacuum to remove the moisture to obtain a membrane, which is a solid electrolyte based on ionic liquid.

[0025] Furthermore, in the step 1), the mixing is carried out at 50 to 60° C. and the mixing time is 1 to 3 hours;

[0026] In the step 2), the thickness of the film is 100-500 μm, and the drying temperature is 70-90° C.

[0027] Furthermore, the organic solvent comprises one or more of tetrahydrofuran, dimethyl carbonate, diethyl carbonate, ethyl acetate, N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone.

[0028] Beneficial effects of the present invention:

[0029] 1. The weight of the solid electrolyte of the present invention decreases by less than 1.0% when heated to 150°C and decreases by 3.6% when heated to 300°C, which is higher than the thermal stability requirement of the solid electrolyte.

[0030] 2. Improve the conductivity and lithium ion migration number: The conductivity of the solid-state battery electrolyte of the present invention is 10 -3 ~10 -4 S / cm, lithium ion migration number 0.6~0.9.

[0031] 3. The capacity retention rate of the battery made of solid electrolyte after 200 cycles is greater than 90%, and the charge and discharge efficiency is above 99%. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The capacity retention rate of the solid-state battery prepared in Example 1 after 200 cycles in the 80% SOC range at 0.2C calibration;

[0033] Figure 2 The CV curve of the solid-state battery prepared in Example 1 after 200 cycles at 80% SOC is calibrated at 0.2C;

[0034] Figure 3 This is the thermal gravimetric diagram of the solid electrolyte prepared in Example 1. DETAILED DESCRIPTION

[0035] The present invention provides a solid electrolyte based on ionic liquid, comprising the following components in parts by weight:

[0036]

[0037] The electrolyte matrix comprises a solid ionic liquid and a polymer;

[0038] The polymer comprises a polyionic liquid and one or more of polyethylene oxide, poly-1,3-dioxolane, polyvinyl ethylene carbonate, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer and polyacrylonitrile.

[0039] In the present invention, the mass ratio of the solid ionic liquid to the polymer is 10-90:90-10, preferably 30-70:30-70, and more preferably 40-60:40-60.

[0040] In the present invention, the solid ionic liquid is preferably 1,3-dimethylimidazolium bisfluorosulfonyl imide, N,N-dimethylpyrrolidine bistrifluoromethylsulfonyl imide, N,N-dimethylpyrrolidine tetrafluoroborate, N-methyl-N-ethylpyrrolidine bisfluorosulfonyl imide, N-methyl-N-ethylpyrrolidine bistrifluoromethylsulfonyl imide, N,N-dimethylpiperidinium bisfluorosulfonyl imide, N,N-dimethylpiperidinium bistrifluoromethylsulfonyl imide, N-ethyl-N-methylpiperidinium One or more of bis(fluorosulfonyl)imide salts of piperidine, N-ethyl-N-methylpiperidinium bis(trifluoromethylsulfonyl)imide salts, tetramethylammonium bis(fluorosulfonyl)imide salts, dimethyldiethylammonium bis(fluorosulfonyl)imide salts, dimethyldiethylammonium bis(trifluoromethylsulfonyl)imide salts, 1,1-spirobipyrrolidine bis(fluorosulfonyl)imide salts, 1,1-spirobipyrrolidine tetrafluoroborate, tetraethylammonium tetrafluoroborate, tetraethylammonium hexafluorophosphate, tetrabutylammonium bis(trifluoromethylsulfonyl)imide salts and tetrabutylammonium bis(fluorosulfonyl)imide salts.

[0041] In the present invention, the polyionic liquid is preferably poly 1-vinyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, poly 1-vinyl-3-methylimidazolium bis(fluorosulfonyl)imide, poly 1-vinyl-3-ethylimidazolium hexafluorophosphate, poly 1-vinyl-3-ethylimidazolium bis(fluorosulfonyl)imide, poly-1-vinyl-3-ethylimidazolium bis(trifluoromethyl)sulfonyl imide, poly-1-vinyl-3-butylimidazolium bis(trifluoromethyl)sulfonyl imide, poly-1-vinyl-3-butylimidazolium bis(fluorosulfonyl)imide, poly 1-allyl-3-methylimidazolium methyl sulfate, poly 1-allyl-3-methylimidazolium tetrafluoroborate, poly 1-allyl-3-methylimidazolium bis(trifluoromethyl)sulfonyl imide, poly-1-vinyl-3 -allylimidazole bis(trifluoromethyl)sulfonyl imide salt, poly 1-vinyl-3-allylimidazole tetrafluoroborate, poly 1-vinyl-3-allylimidazole hexafluorophosphate, poly-1-vinyl-3-benzylimidazole bis(trifluoromethyl)sulfonyl imide salt, poly dimethylallylammonium bis(trifluoromethyl)sulfonyl imide salt, poly dimethyldiallylammonium bis(trifluoromethyl)sulfonyl imide salt, poly 1-(4-allylbenzyl)-3-ethylimidazole bis(trifluoromethyl)sulfonyl imide salt, poly 1-(epoxypropyl)-3-methylimidazole bis(trifluoromethyl)sulfonyl imide salt, poly 1-(epoxypropyl)-3-methylimidazole bis(trifluoromethyl)sulfonyl imide salt, and one or more of poly 3-butyl-1-(2-(methacryloyloxy)ethyl)imidazole bis(trifluoromethyl)sulfonyl imide salt.

[0042] In the present invention, the plasticizer comprises one or more of liquid ionic liquid, polyethylene glycol, trioxymethylene, succinonitrile and 1,2-dimethoxyethane, preferably a liquid ionic liquid.

[0043] In the present invention, the lithium salt comprises one or more of lithium bis(oxalatoborate), lithium difluorooxalatoborate, lithium bis(trifluoromethanesulfonylimide), lithium bis(fluorosulfonylimide), lithium hexafluorophosphate, lithium perchlorate and lithium tetrafluoroborate, preferably one or more of lithium bis(oxalatoborate), lithium difluorooxalatoborate and lithium bis(trifluoromethanesulfonylimide).

[0044] In the present invention, the liquid ionic liquid is compounded by one or more ionic liquids composed of the following anions and cations:

[0045] The cation comprises 1-ethyl-3-methylimidazolium cation, 1-propyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation, 1-ethylmethoxy-3-methylimidazolium cation, 1-ethyl-3-methylpyrrolidinium cation, 1-propyl-3-methylpyrrolidinium cation, 1-butyl-3-methylpyrrolidinium cation, 1-ethylmethoxy-3-methylpyrrolidinium cation, N-ethyl-N-methylpiperidinium cation, N-propyl-N-methylpiperidinium cation, N-butyl-N-methylpiperidinium cation or N-ethylmethoxy-N-methylpiperidinium cation;

[0046] The anion comprises bis(fluorosulfonyl)imide, bis(trifluoromethanesulfonyl)imide, hexafluorophosphoric acid, bis(oxalyl)boric acid, trifluoromethanesulfonic acid, tetrafluoroboric acid or perchloric acid.

[0047] In the present invention, the liquid ionic liquid is preferably 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, N-propyl-N-methylpyrrolidine bis(trifluoromethylsulfonyl)imide, or 1-methoxyethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide.

[0048] In the present invention, the organic framework material comprises one or more of ZIF-67, ZIF-8, TpPa-SO3Li, DMTHA-Si-Li, TAPT-DMTP and TAPT-DVA.

[0049] In the present invention, the structural formula of the TpPa-SO3Li is as follows:

[0050]

[0051] The structural formula of the DMTHA-Si-Li is shown below:

[0052]

[0053] In the present invention, the ionic liquid and plasticizer components can improve the conductivity of the solid-state battery electrolyte, and the polymer improves the mechanical properties and flexibility of the electrolyte. The MOF or COF is prepared by adding bis(trifluoromethylsulfonyl)imide (TFSI) - ) is anchored to the polymer skeleton, which can increase the number of lithium ion migration; the flexible nature of the electrolyte and the movement of the disordered ionic liquid inside will make the contact with the positive and negative electrode interfaces more perfect.

[0054] The present invention provides a method for preparing a solid electrolyte based on an ionic liquid, comprising the following steps:

[0055] 1) mixing a solid ionic liquid, a polymer, a lithium salt, a plasticizer and an organic framework material in an organic solvent, and dissolving or dispersing them uniformly to obtain a mixed solution;

[0056] 2) The mixed solution is poured into a mold to evaporate the organic solvent, and finally the mixture is dried under vacuum to remove the moisture to obtain a membrane, which is a solid electrolyte based on ionic liquid.

[0057] In the present invention, in the step 1), the mixing is carried out at 50-60° C., preferably 60° C.; the mixing time is 1-3 h, preferably 2 h.

[0058] In the present invention, in the step 2), the thickness of the film is 100-500 μm, preferably 200-400 μm; the drying temperature is 70-90°C, preferably 80°C.

[0059] In the present invention, the selection of the organic solvent is not particularly limited, and can be any solvent in which the reagent can be at least partially dissolved, preferably one or more of tetrahydrofuran, dimethyl carbonate, diethyl carbonate, ethyl acetate, N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone.

[0060] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0061] Example 1

[0062] The electrolyte matrix is ​​obtained by mixing 50 parts of a solid part of amorphous ionic liquid 1,3-dimethyl imidazole bis trifluoromethyl sulfonyl imide salt and 50 parts of poly 1-vinyl-3-butyl imidazole bis trifluoromethyl sulfonyl imide salt;

[0063] Dissolve 100 parts of electrolyte matrix, 15 parts of lithium bis(trifluoromethanesulfonyl)imide, 8 parts of trioxymethylene and 3 parts of DMTHA-Si-Li in 232 parts of N,N-dimethylformamide to obtain a slurry;

[0064] The slurry is coated on the surface of the ternary positive electrode material with a coating thickness of 0.5 mm, and then dried at 80°C for 2 hours. The solvent is evaporated to obtain a 420μm film, which is the solid electrolyte. The negative electrode is stacked on the coating surface in a stacked manner to obtain a solid electrolyte and a solid-state battery.

[0065] Embodiment 2 to Embodiment 8

[0066] The preparation method is the same as that of Example 1, except that the raw materials and the proportions are different. The raw materials and the proportions are shown in Table 1 below.

[0067] Table 1 Raw materials and proportions of the examples

[0068]

[0069]

[0070]

[0071] The solid-state batteries obtained in Examples 1 to 8 were subjected to performance tests, and the test results are shown in Table 2 below.

[0072] Table 2 Test results

[0073]

[0074]

[0075] In Table 2, by comparing Examples 1 and 2, it can be seen that the proportion of the covalent organic framework of lithium ions has an impact on both the conductivity and the lithium ion migration number, where the conductivity shows an upward trend as the proportion of DMTHA-Si-Li increases. However, Example 2, which does not add the sticky poly 1-(epoxypropyl)-3-methylimidazole bis(trifluoromethyl)sulfonyl imide salt and plasticizer, has poor film-forming properties. By comparing Examples 4 and 6 with other solutions, it can be seen that the addition of organic framework materials can effectively improve the lithium ion migration number. Figure 1 and Figure 2 It can be seen that this solid electrolyte battery based on ionic liquid has a gram capacity of 140mAh / g, a coulombic efficiency of about 99%, and small electrolyte polarization.

[0076] It can be seen from the above embodiments that the present invention provides a solid electrolyte based on ionic liquid and a preparation method thereof. The technical solution of the present invention mainly solves: 1) How to prepare a safe ionic liquid electrolyte that remains solid at high temperatures above 200 degrees; 2) How to improve the flexibility of the ionic liquid electrolyte; 3) Improve the conductivity and lithium ion migration number of the solid-state battery electrolyte to improve the performance of the solid-state battery. The weight of the solid electrolyte of the present invention decreases by less than 1.0% when heated to 150°C, and decreases by 3.6% when heated to 300°C, which is higher than the thermal stability requirement of the solid electrolyte.

[0077] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A solid electrolyte based on ionic liquid, characterized in that: Contains the following components in parts by weight: The electrolyte matrix comprises a solid ionic liquid and a polymer; The polymer comprises a polyionic liquid and one or more of polyethylene oxide, poly-1,3-dioxolane, polyvinyl ethylene carbonate, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer and polyacrylonitrile.

2. The ionic liquid-based solid electrolyte according to claim 1, characterized in that The mass ratio of the solid ionic liquid to the polymer is 10-90:90-10.

3. The solid electrolyte based on ionic liquid according to claim 1 or 2, characterized in that The solid ionic liquid comprises 1,3-dimethyl imidazolium bisfluorosulfonyl imide salt, N,N-dimethyl pyrrolidine bis trifluoromethyl sulfonyl imide salt, N,N-dimethyl pyrrolidine tetrafluoroborate, N-methyl-N-ethyl pyrrolidine bis trifluoromethyl sulfonyl imide salt, N,N-dimethyl piperidine bis trifluoromethyl sulfonyl imide salt, N,N-dimethyl piperidine bis trifluoromethyl sulfonyl imide salt, N-ethyl-N-methyl piperidine bis trifluoromethyl sulfonyl imide salt, One or more of imide salts, N-ethyl-N-methylpiperidinium bis(trifluoromethylsulfonyl)imide salts, tetramethylammonium bis(fluorosulfonyl)imide salts, dimethyldiethylammonium bis(fluorosulfonyl)imide salts, dimethyldiethylammonium bis(trifluoromethylsulfonyl)imide salts, 1,1-spirobipyrrolidine bis(fluorosulfonyl)imide salts, 1,1-spirobipyrrolidine tetrafluoroborate, tetraethylammonium tetrafluoroborate, tetraethylammonium hexafluorophosphate, tetrabutylammonium bis(trifluoromethylsulfonyl)imide salts and tetrabutylammonium bis(fluorosulfonyl)imide salts.

4. The ionic liquid-based solid electrolyte according to claim 3, characterized in that The polyionic liquid comprises poly 1-vinyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide salt, poly 1-vinyl-3-methylimidazolium bis(fluorosulfonyl)imide salt, poly 1-vinyl-3-ethylimidazolium hexafluorophosphate salt, poly 1-vinyl-3-ethylimidazolium bis(fluorosulfonyl)imide salt, poly-1-vinyl-3-ethylimidazolium bis(trifluoromethyl)sulfonyl imide salt, poly-1-vinyl-3-butylimidazolium bis(trifluoromethyl)sulfonyl imide salt, poly-1-vinyl-3-butylimidazolium bis(fluorosulfonyl)imide salt, poly 1-allyl-3-methylimidazolium methyl sulfate salt, poly 1-allyl-3-methylimidazolium tetrafluoroborate, poly 1-allyl-3-methylimidazolium bis(trifluoromethyl)sulfonyl imide salt, poly-1-vinyl-3-allyl One or more of imidazole bis(trifluoromethyl)sulfonyl imide salt, poly 1-vinyl-3-allylimidazole tetrafluoroborate, poly 1-vinyl-3-allylimidazole hexafluorophosphate, poly-1-vinyl-3-benzylimidazole bis(trifluoromethyl)sulfonyl imide salt, poly dimethylallylammonium bis(trifluoromethyl)sulfonyl imide salt, poly dimethyldiallylammonium bis(trifluoromethyl)sulfonyl imide salt, poly 1-(4-allylbenzyl)-3-ethylimidazole bis(trifluoromethyl)sulfonyl imide salt, poly 1-(epoxypropyl)-3-methylimidazole bis(trifluoromethyl)sulfonyl imide salt, poly 1-(epoxypropyl)-3-methylimidazole bis(trifluoromethyl)sulfonyl imide salt, and poly 3-butyl-1-(2-(methacryloyloxy)ethyl)imidazole bis(trifluoromethyl)sulfonyl imide salt.

5. The ionic liquid-based solid electrolyte according to claim 4, characterized in that The plasticizer comprises one or more of liquid ionic liquid, polyethylene glycol, trioxymethylene, succinonitrile and 1,2-dimethoxyethane; The lithium salt comprises one or more of lithium bis(oxalatoborate), lithium difluorooxalatoborate, lithium bis(trifluoromethanesulfonylimide), lithium bis(fluorosulfonylimide), lithium hexafluorophosphate, lithium perchlorate and lithium tetrafluoroborate.

6. The ionic liquid-based solid electrolyte according to claim 5, characterized in that The liquid ionic liquid is compounded by one or more ionic liquids composed of the following anions and cations: The cation comprises 1-ethyl-3-methylimidazolium cation, 1-propyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation, 1-ethylmethoxy-3-methylimidazolium cation, 1-ethyl-3-methylpyrrolidinium cation, 1-propyl-3-methylpyrrolidinium cation, 1-butyl-3-methylpyrrolidinium cation, 1-ethylmethoxy-3-methylpyrrolidinium cation, N-ethyl-N-methylpiperidinium cation, N-propyl-N-methylpiperidinium cation, N-butyl-N-methylpiperidinium cation or N-ethylmethoxy-N-methylpiperidinium cation; The anion comprises bis(fluorosulfonyl)imide, bis(trifluoromethanesulfonyl)imide, hexafluorophosphoric acid, bis(oxalyl)boric acid, trifluoromethanesulfonic acid, tetrafluoroboric acid or perchloric acid.

7. The ionic liquid-based solid electrolyte according to claim 1, 5 or 6, characterized in that: The organic framework material comprises one or more of ZIF-67, ZIF-8, TpPa-SO3Li, DMTHA-Si-Li, TAPT-DMTP and TAPT-DVA.

8. The method for preparing a solid electrolyte based on an ionic liquid according to any one of claims 1 to 7, characterized in that: The following steps are involved: 1) mixing a solid ionic liquid, a polymer, a lithium salt, a plasticizer and an organic framework material in an organic solvent, and dissolving or dispersing them uniformly to obtain a mixed solution; 2) The mixed solution is poured into a mold to evaporate the organic solvent, and finally the mixture is dried under vacuum to remove the moisture to obtain a membrane, which is a solid electrolyte based on ionic liquid.

9. The preparation method according to claim 8, characterized in that: In the step 1), the mixing is carried out at 50-60° C. and the mixing time is 1-3 hours; In the step 2), the thickness of the film is 100 to 500 μ m, the drying temperature is 70~90℃.

10. The preparation method according to claim 8 or 9, characterized in that: The organic solvent comprises one or more of tetrahydrofuran, dimethyl carbonate, diethyl carbonate, ethyl acetate, N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone.

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