Gel electrolyte, in-situ curing electrolyte and lithium ion battery

Abstract

The invention relates to the field of lithium ion batteries, and discloses a gel electrolyte, an in-situ curing electrolyte and a lithium ion battery. The gel electrolyte comprises a solvent, a polymer and a metal salt, wherein the polymer is a heterochain polymer with a main chain or a side chain containing a sulfur-containing siloxane group and a nitrogen-containing group. A main chain or a side chain of a polymer in the gel electrolyte contains a sulfur-containing siloxane group and a nitrogen-containing group, so that volatilization and leakage of a solvent can be inhibited, excellent liquid retention performance is brought, the thermal safety of a battery is improved, an interface side reaction can be inhibited, and the high-temperature and high-pressure stability of the battery is improved.

Description

Gel electrolytes, in-situ solidified electrolytes, and lithium-ion batteries Technical Field

[0001] This invention relates to the field of lithium-ion batteries, specifically to a gel electrolyte, an in-situ solidified electrolyte, and a lithium-ion battery. Background Technology

[0002] Lithium-ion batteries are widely used due to their high energy density and excellent electrochemical properties, and their safety performance is receiving increasing attention. Liquid batteries, on the other hand, have always been a difficult problem for the industry to solve due to their disadvantages such as easy solvent evaporation, leakage risk, and interfacial side reactions.

[0003] Currently, using gel electrolytes to reduce free electrolyte and thus improve the leakage risk of liquid batteries is an effective way to enhance the safety performance of lithium-ion batteries. However, general gel electrolytes cannot effectively suppress the volatilization of electrolyte solvents and interfacial side reactions.

[0004] CN116581378A discloses an interface self-healing polymer electrolyte and its preparation method and application. The preparation method includes the following steps: (1) adding a monomer (terephthalic dimethyl dithiocyanate) containing polymerizable functional groups and a monomer (terephthalic polyester polyol) containing lithium-ion conducting functional groups to a solvent to react and obtain a preliminary polymer matrix solution; (2) adding a monomer chain extender (4,4-disulfide bond group) containing dynamic disulfide bond functional groups to the preliminary polymer matrix solution. (3) Add plasticizing additives and lithium salts to the polymer solution to obtain a gel electrolyte with self-healing function.

[0005] CN117050232A discloses a solid polymer electrolyte, a lithium-ion battery, and a terminal comprising the same. The polymer electrolyte is obtained by in-situ polymerization and crosslinking of polymeric monomers, crosslinking agents, initiators, lithium salts, and solvents, wherein the molecular structure of the polymeric monomers includes ether groups, acrylate groups, and high-voltage resistant functional groups.

[0006] The above-mentioned methods employ monomers containing highly polar functional groups to prepare gel electrolytes. They utilize the dipole-dipole interactions and van der Waals forces between the polar functional groups and the polar solvent in the electrolyte to further bind the solvent and suppress its volatility. While these methods suppress solvent evaporation and electrolyte leakage to some extent, the relatively weak interaction forces prevent them from effectively suppressing electrolyte evaporation or interfacial side reactions. Summary of the Invention

[0007] This invention addresses the problems of existing gel electrolytes, such as unsatisfactory liquid retention, difficulty in suppressing interfacial side reactions, and poor performance under high temperature and high pressure. It provides a gel electrolyte, an in-situ solidified electrolyte, and a lithium-ion battery.

[0008] To achieve the above objectives, the present invention provides a gel electrolyte in a first aspect, the gel electrolyte comprising: a solvent, a polymer, and a metal salt; wherein the polymer is a heterochain polymer whose main chain or side chain contains sulfur-containing siloxane groups and nitrogen-containing groups.

[0009] In a second aspect, the present invention provides an in-situ curing electrolyte comprising: a sulfur-containing silane coupling agent, a double-bonded monomer having a nitrogen-containing group, an electrolyte, and an initiator.

[0010] In a third aspect, the present invention provides a gel electrolyte, which is formed by in-situ polymerization of the in-situ solidified electrolyte described in the second aspect above.

[0011] The present invention provides a lithium-ion battery in a fourth aspect, wherein the lithium-ion battery contains the gel electrolyte described in the first or third aspect above.

[0012] The gel electrolyte provided by this invention comprises a heterochain polymer, wherein the main chain or side chain of the polymer contains sulfur-containing siloxane groups and nitrogen-containing groups. The nitrogen-containing groups can help to firmly bind solvent molecules, inhibit their volatilization and leakage, and improve the thermal safety performance of the battery. The silanoxy groups can form interface modification on the positive electrode surface through reaction, accelerating lithium ion movement. The nitrogen and low-valence sulfur elements in the polymer can promote the formation of a stable CEI film rich in lithium nitride and lithium sulfide, and can capture and inhibit oxygen release from the positive electrode, reduce side reactions, and improve the high-temperature and high-pressure stability of the battery. Detailed Implementation

[0013] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise 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 the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0014] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0015] In a first aspect, the present invention provides a gel electrolyte comprising: a solvent, a polymer, and a metal salt; wherein the polymer is a heterochain polymer whose main chain or side chain contains sulfur-containing siloxane groups and nitrogen-containing groups.

[0016] The gel electrolyte provided by this invention is based on the structural design of a polymer. The polymer is a heterochain polymer with sulfur-containing siloxane groups and nitrogen-containing groups in its main chain or side chains. The nitrogen-containing groups in the polymer can not only inhibit solvent evaporation through dipole interactions and van der Waals forces, but also form intermolecular hydrogen bonds with the electrolyte solvent. This hydrogen bonding force firmly binds the solvent molecules, inhibiting their evaporation and leakage, and improving the thermal safety performance of the battery. The silanoxy groups in the polymer can react under the catalysis of LiOH on the surface of the positive electrode material to form Si-O-Si covalent bonds, which coat the surface of the positive electrode and form an interface modification, making the contact between the electrode and the electrolyte tighter, reducing the interfacial impedance, and accelerating the lithium-ion transfer kinetics. The nitrogen and low-valent sulfur elements contained in the polymer can promote the formation of a thin and stable CEI film rich in lithium nitride and lithium sulfide, promote the interfacial transport kinetics of lithium ions, and at the same time capture and inhibit the release of active oxygen from the positive electrode, reduce the side reactions between the positive and negative electrodes and the electrolyte, and improve the high-temperature and high-pressure stability of the battery.

[0017] According to the present invention, the polymer contained in the gel electrolyte further comprises repeating units containing sulfur-containing siloxane groups and repeating units containing nitrogen groups.

[0018] According to the present invention, in the polymer contained in the gel electrolyte, preferably, the sulfur-containing siloxane group has the structure shown in formula (I); Formula (I); wherein R1 is a chain segment containing the structure shown in Formula (II) or Formula (III), and the two ends of the chain segment with the structure shown in Formula (II) or Formula (III) are respectively connected to straight-chain alkyl or branched alkyl with the number of carbon atoms between 0 and 10; Formula (II); Formula (III); According to the present invention, in the polymer contained in the gel electrolyte, in Formula (I), preferably, R1 contains not less than 2 sulfur atoms.

[0019] According to the present invention, in the polymer contained in the gel electrolyte, in formula (I), more preferably, R1 is a chain segment containing the structure shown in formula (III).

[0020] In this invention, the polymer contains the aforementioned preferred sulfur-containing siloxane groups, which can give the gel electrolyte better performance in suppressing interfacial side reactions and improve its high-temperature and high-pressure stability.

[0021] According to the present invention, the nitrogen-containing groups in the polymer contained in the gel electrolyte are selected from amide groups or urea groups.

[0022] According to the present invention, in the polymer contained in the gel electrolyte, preferably, the nitrogen atom in the nitrogen-containing group is bonded to at least one hydrogen atom.

[0023] According to the present invention, in the polymer contained in the gel electrolyte, preferably, the repeating unit containing nitrogen-containing groups contains at least two nitrogen atoms, and each nitrogen atom is bonded to at least one hydrogen atom.

[0024] In this invention, the polymer contains repeating units of the aforementioned preferred nitrogen-containing groups, which can give the gel electrolyte better liquid-locking performance and improve its high-temperature and high-pressure stability.

[0025] According to the present invention, in the polymer contained in the gel electrolyte, the molar ratio of the sulfur-containing siloxane group to the nitrogen-containing group is 1:(0.1-10), for example, it can be 1:0.1, 1:0.3, 1:0.5, 1:0.7, 1:0.9, 1:1, 1:1.3, 1:1.5, 1:1.7, 1:1.9, 1:2, 1:2.3, 1:2.5, 1:2.7, 1:2.9, 1:3, 1:3.3, 1:3.5, 1:3.7, 1:3.9, 1:4, or 1:4. 3, 1:4.5, 1:4.7, 1:4.9, 1:5, 1:5.3, 1:5.5, 1:5.7, 1:5.9, 1:6, 1:6.3, 1:6.5, 1:6.7, 1:6.9, 1:7, 1:7.3, 1:7.5, 1:7.7, 1:7.9, 1:8, 1:8.3, 1:8.5, 1:8.7, 1:9, 1:9.3, 1:9.5, 1:9.7, 1:9.7, 1:10, and any value within any two of the above numerical component ranges.

[0026] According to the present invention, in the polymer, the sulfur-containing siloxane group and the nitrogen-containing group, based on the above-mentioned proportional relationship, preferably have a molar ratio of sulfur-containing siloxane group to nitrogen-containing group of 1:(2-10), which enables the gel electrolyte to generate a thinner and denser interfacial film while effectively suppressing interfacial side reactions, and has further improved liquid-locking performance.

[0027] According to the present invention, in the gel electrolyte, preferably, the polymer accounts for 2-30% of the weight of the gel electrolyte (based on the total weight of the gel electrolyte), for example, it can be 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, and any value in any two of the above-mentioned numerical component ranges.

[0028] More preferably, the polymer accounts for 2-15% by weight in the gel electrolyte.

[0029] According to the present invention, preferably, the concentration of the metal salt in the gel electrolyte is 0.5-5 mol / L, for example, it can be 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L, 3 mol / L, 3.5 mol / L, 4 mol / L, 4.5 mol / L, 5 mol / L, and any value within any two of the above-mentioned numerical ranges.

[0030] More preferably, the concentration of the metal salt in the gel electrolyte is 1-3 mol / L.

[0031] According to the present invention, the metal salt in the gel electrolyte is subject to a wide range of selection, and metal salts known in the art for use in gel electrolytes can be employed. Preferably, the metal salt may be selected from at least one of LiPF6, LiFSI, LiTFSI, LiDFOB, LiBF4, LiBOB, LiPO2F2, and LiFTFSI.

[0032] More preferably, the metal salt may be selected from at least one of LiPF6, LiFSI, LiTFSI, LiDFOB and LiBF4.

[0033] According to the present invention, the solvent in the gel electrolyte is broadly defined, and can be any organic solvent known in the art that can be used in gel electrolytes, including but not limited to carbonate-based solvents, ether-based solvents, and nitrile-based solvents. For example, the solvent can be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, dimethyl carbonate, succinic acid, diethyl carbonate, 1,2-dimethoxyethane, 1,3-dioxolane, fluoroethylene carbonate, ethyl acetate, propyl formate, propyl propionate, and γ-butyrolactone.

[0034] According to a preferred embodiment of the present invention, in the gel electrolyte, the polymer contains repeating units of sulfur-containing siloxane groups (the sulfur-containing siloxane groups have the structure shown in the aforementioned formula (I), wherein R1 contains...) ) and repeating units containing nitrogen groups (nitrogen groups containing The preferred composition of the gel electrolyte has a molar ratio of sulfur-containing siloxane groups to nitrogen-containing groups of 1:(2-10), a polymer weight percentage of 2-15%, and a metal salt concentration of 1-3 mol / L. The gel electrolyte with this preferred composition exhibits enhanced overall performance in terms of high liquid retention, suppression of interfacial side reactions, and high-temperature and high-pressure stability.

[0035] In a second aspect, the present invention provides an in-situ curing electrolyte comprising: a sulfur-containing silane coupling agent, a double-bonded monomer having a nitrogen-containing group, an electrolyte, and an initiator.

[0036] According to the present invention, in the in-situ cured electrolyte, the sulfur-containing silane coupling agent satisfies the general chemical formula: YR-SiX3.

[0037] According to the present invention, in the above chemical formula, preferably, X is selected from -OCH3, -OCH2CH3, -OCH(CH3)2 or -OCOCH3.

[0038] According to the present invention, in the above general chemical formula, Y can be selected from -SH, -CH=CH2 or -C(CH3)=CH2.

[0039] According to the present invention, in the above general chemical formula, when Y is selected from -SH, R is selected from CO-C with or without +2 valence sulfur. 10 Alkyl groups, or C0-C 10 Alkyl thiols, or C0-C 10 Alkenyl thiols; when Y is selected from -CH=CH2 or -C(CH3)=CH2; R is selected from CO-C containing a +2 valence sulfur element. 10 Alkyl groups, or C0-C 10 Alkyl thiols, or C0-C 10 alkenyl thiols.

[0040] According to the present invention, in the in-situ solidified electrolyte, the sulfur-containing silane coupling agent satisfies the above-mentioned general chemical formula. After polymerization with a monomer having a nitrogen-containing double bond, it can provide silaneoxy groups and low-valent sulfur elements to the polymer formed by polymerization. The silaneoxy groups can react under the catalysis of LiOH on the surface of the positive electrode material to generate Si-O-Si covalent bonds, which coat the surface of the positive electrode, making the electrode and electrolyte more closely connected, reducing interfacial impedance, and accelerating lithium-ion transfer kinetics. At the same time, the low-valent sulfur elements can generate a thin and stable CEI rich in lithium sulfide, which can promote the interfacial transport kinetics of lithium ions, while capturing and inhibiting the release of active oxygen from the positive electrode, reducing the reaction between the positive and negative electrodes and the electrolyte, and improving the high-temperature and high-pressure stability of the battery.

[0041] According to the present invention, in the in-situ cured electrolyte, the sulfur-containing silane coupling agent, in addition to satisfying the above-mentioned general chemical formula, preferably contains at least two sulfur atoms (a molecule of the sulfur-containing silane coupling agent contains at least two sulfur atoms).

[0042] Preferably, the sulfur-containing silane coupling agent is further selected from mercaptopropyltrimethoxysilane, methimoxytrimethoxysilane, 2-[(trimethoxysilyl)methyl]-1,3-propanedithiol, (mercaptomethyl)triethoxysilane, mercaptopropyltriethoxysilane, methimoxytributoxysilane, 1-trimethoxysilylpropane-2-thiol, 1-triethoxysilylethane-1,2-dithiol, 2-vinylthioethyl(triethoxy)silane, 2-vinylthio At least one of ethylthiomethyl(trimethoxy)silane, trimethoxy(2-propenylthiomethyl)silane, 1-trimethoxysilylmethylthio-1-buten-3-yne, 2-trimethoxysilyl ethanethiol, trimethoxy(3-vinylthiopropyl)silane, 1-(vinylthioethyl)triethoxysilane, 3-(2-propenylthioethylthio)propyltrimethoxysilane, and 3-(2-vinylthioethylthio)propyltrimethoxysilane.

[0043] According to a further preferred embodiment of the present invention, the sulfur-containing silane coupling agent is selected from at least one of 2-[(trimethoxysilyl)methyl]-1,3-propanedithiol, 1-triethoxysilylethane-1,2-dithiol, 2-vinylthioethylthiomethyl(trimethoxy)silane, 3-(2-propenylthioethylthio)propyltrimethoxysilane, and 3-(2-vinylthioethylthio)propyltrimethoxysilane.

[0044] According to the present invention, in the in-situ solidified electrolyte, the nitrogen-containing group in the double-bonded monomer with nitrogen-containing group is selected from at least one of amide group or urea group. Preferably, the nitrogen atom in the nitrogen-containing group is bonded to at least one hydrogen atom. After the double-bonded monomer with nitrogen-containing group is polymerized with the sulfur-containing silane coupling agent, it can provide nitrogen-containing groups and low-valent nitrogen elements to the polymer formed by polymerization. It can form intermolecular hydrogen bonds with the electrolyte solvent, and firmly bind the solvent molecules through hydrogen bonding forces, suppressing its volatility and leakage risk, and improving the thermal safety performance of the battery. At the same time, the low-valent nitrogen elements can generate a thin and stable CEI rich in lithium nitride, which can promote the interfacial transport kinetics of lithium ions, capture and suppress the release of active oxygen from the positive electrode, reduce the reaction between the positive and negative electrodes and the electrolyte, and improve the high temperature and high pressure stability of the battery.

[0045] According to the present invention, preferably, the double-bonded monomer having a nitrogen-containing group can be selected from at least one of methacrylamide ethyl ethylene urea, N-(isobutoxymethyl)acrylamide, 2-(1,2-cyclohexanedicarboxyimide) ethyl acrylate, N-vinylcaprolactam, diacetone acrylamide, 2-(tert-butylamino) ethyl methacrylate, ethylidene methacrylate ethoxylate, dimethylaminopropyl acrylamide, a mixture of diurea dimethacrylate isomers, N,N'-methylenebisacrylamide, N-vinylformamide, N-isopropylmethylacrylamide, 1-allylhydantoin, N-(1,1,3,3-tetramethylbutyl)acrylamide, 3-butenylurea, and N-(2-amino-2-oxoethyl)acrylamide.

[0046] In this invention, more preferably, the double-bonded monomer with nitrogen-containing groups contains at least two nitrogen atoms, and each nitrogen atom is connected to at least one hydrogen atom. This is more conducive to improving the liquid retention of the gel electrolyte formed after in-situ polymerization of the in-situ solidified electrolyte and the ability to suppress interfacial side reactions, thereby further improving the high-temperature and high-pressure stability and safety performance of the battery.

[0047] According to a further preferred embodiment of the present invention, the double-bonded monomer having a nitrogen-containing group is selected from at least one of methacrylamide ethyl ethylene urea, N,N'-methylenebisacrylamide, a mixture of diurea dimethacrylate isomers, 3-butenyl urea, and N-(2-amino-2-oxoethyl)acrylamide.

[0048] According to the present invention, the in-situ solidified electrolyte comprises a metal salt and a solvent.

[0049] In this invention, the metal salt in the electrolyte is broadly defined, and metal salts known in the art for use in gel electrolytes can be selected. Preferably, the metal salt can be selected from at least one of LiPF6, LiFSI, LiTFSI, LiDFOB, LiBF4, LiBOB, LiPO2F2, and LiFTFSI.

[0050] In this invention, the solvent in the electrolyte is broadly defined, and organic solvents known in the art for use in gel electrolytes can be selected, including but not limited to carbonate-based solvents, ether-based solvents, and nitrile-based solvents. For example, the solvent can be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, dimethyl carbonate, succinic acid, diethyl carbonate, 1,2-dimethoxyethane, 1,3-dioxolane, fluoroethylene carbonate, ethyl acetate, propyl formate, propyl propionate, and γ-butyrolactone.

[0051] In this invention, preferably, the concentration of the metal salt in the electrolyte is 1-3 mol / L.

[0052] According to the present invention, the electrolyte further contains additives that facilitate the formation of an excellent SEI / CEI interfacial film, further improving the electrical properties of the electrolyte formed after in-situ polymerization. Preferably, the additives may include, but are not limited to, at least one of vinylene carbonate (VC), dimethyl dithiocarbonate (DTD), biphenyl (BP), cyclohexylbenzene (CHB), propane sulpholol (PS), triethyl phosphate (TEP), lithium nitrate (LiNO3), and methyl ethyl fluorocarbonate (FEMC).

[0053] In this invention, preferably, the content of additives in the electrolyte is 0.01-10% by weight.

[0054] According to the present invention, the initiator in the in-situ curing electrolyte has a wide selection range and can be a conventional initiator capable of initiating free radical polymerization. For example, the initiator can be selected from at least one of diethyl dicarbonate peroxide (DEPO), benzoyl peroxide (BPO), azobisisobutyronitrile (AIBN), dicumyl peroxide (DCP), lauroyl peroxide (LPO), azobisisoheptanenitrile (ABVN), potassium persulfate (KPS), ammonium persulfate (APS), and diethyl dicarbonate peroxide (DEP).

[0055] According to the present invention, in the in-situ cured electrolyte, preferably, the weight ratio of the sulfur-containing silane coupling agent to the double-bonded monomer having a nitrogen-containing group is (0.1-10):1, more preferably (0.1-0.5):1.

[0056] According to the present invention, in the in-situ curing electrolyte, preferably, the weight ratio of (sulfur-containing silane coupling agent + double bond monomer with nitrogen-containing group): in-situ curing electrolyte is (2-30):100.

[0057] According to the present invention, in the in-situ solidified electrolyte, preferably, the weight ratio of the initiator to (sulfur-containing silane coupling agent + double bond monomer with nitrogen-containing group) is (0.05-3):100.

[0058] The in-situ solidified electrolyte provided by this invention contains the aforementioned specific polymeric monomers. After copolymerization, a polymer with a specific structural composition can be obtained, thereby forming a gel polymer electrolyte with interface modification and high liquid retention. After polymerization, the nitrogen-containing groups in the nitrogen-containing double-bonded monomers can form intermolecular hydrogen bonds with the electrolyte solvent, thus firmly binding the solvent molecules through hydrogen bonding forces, inhibiting their volatilization and leakage, and improving the thermal safety performance of the battery. After polymerization, the silanoxy groups in the sulfur-containing silane coupling agent can react under the catalysis of LiOH on the surface of the positive electrode material to generate Si-O-Si covalent bonds, coating the positive electrode surface and forming interface modification, making the electrode and electrolyte contact closer, reducing interfacial impedance, and accelerating lithium-ion transfer kinetics. After polymerization, the nitrogen and low-valent sulfur elements from the aforementioned polymeric monomers can promote the formation of a thin and stable CEI film rich in lithium nitride and lithium sulfide, promoting lithium-ion interfacial transport kinetics, while simultaneously capturing and inhibiting the release of active oxygen from the positive electrode, reducing side reactions between the positive and negative electrodes and the electrolyte, and improving the high-temperature and high-pressure stability of the battery.

[0059] The in-situ solidified electrolyte provided by the present invention can be prepared by mixing its components.

[0060] In a third aspect, the present invention provides a gel electrolyte, which is formed by in-situ polymerization of the in-situ solidified electrolyte described in the second aspect above.

[0061] According to the present invention, the polymeric monomers in the in-situ cured electrolyte can undergo polymerization reactions under certain temperature and pressure conditions (for example, the in-situ cured electrolyte can be injected into a dry cell and in-situ polymerization can be carried out in the cell), thereby forming a gel electrolyte. Preferably, the conditions for the in-situ polymerization reaction include: a temperature of 40-90°C, a pressure of 0.05-0.6 MPa, and a time of 4-18 h.

[0062] In this invention, the gel electrolyte formed by the in-situ solidified electrolyte described in the second aspect above through an in-situ polymerization reaction has the same chemical composition, structure and properties as the gel electrolyte described in the first aspect above, and will not be repeated here.

[0063] The present invention provides a lithium-ion battery in a fourth aspect, wherein the lithium-ion battery contains the gel electrolyte described in the first or third aspect above.

[0064] The lithium-ion battery provided by this invention uses the gel electrolyte provided by this invention, which can have better thermal safety performance and high temperature and high pressure stability.

[0065] The present invention will be described in detail below through examples. Unless otherwise specified, the following examples and comparative examples are all conventional methods; the reagents and materials mentioned are commercially available unless otherwise specified.

[0066] In the following examples and comparative examples, the molar ratio of structural units in the polymers obtained was calculated using the amount of raw materials fed.

[0067] Preparation Example 1: This preparation example illustrates the preparation of an in-situ solidified electrolyte. Ethyl methyl carbonate (EMC), diethyl carbonate (DEC), and ethylene carbonate (EC) were mixed in a volume ratio of 1:1:1. Then, lithium hexafluorophosphate (LiPF6) and lithium bis(fluorosulfonyl)imide (LiFSI) were added. Finally, 5% (by weight of the total electrolyte) of fluoroethylene carbonate (FEC) and 0.5% (by weight of the total electrolyte) of lithium difluorooxalate (LiPO2F2) were added. The mixture was stirred thoroughly until homogeneous, yielding the electrolyte (wherein, the concentration of LiPF6 was 1 mol / L, and the concentration of LiFSI was...). (Concentration 0.5 mol / L); at 25℃, 18 g of the above electrolyte, 0.83 g of 2-vinylthioethylthiomethyl(trimethoxy)silane (CAS: 62811-79-4), 1.17 g of N,N'-methylenebisacrylamide (CAS: 110-26-9) and 0.02 g of azobisisobutyronitrile were stirred evenly to obtain an in-situ cured electrolyte (denoted as L1).

[0068] Preparation Example 2: This preparation example illustrates the preparation of an in-situ solidified electrolyte. Ethyl methyl carbonate (EMC), diethyl carbonate (DEC), and ethylene carbonate (EC) were mixed in a volume ratio of 1:1:1. Then, lithium hexafluorophosphate (LiPF6) and lithium bis(fluorosulfonyl)imide (LiFSI) were added. Finally, 5% by weight of fluoroethylene carbonate (FEC) and 0.5% by weight of lithium difluorooxalate (LiPO2F2) were added. The mixture was stirred thoroughly until homogeneous, yielding an electrolyte (where the concentration of LiPF6 was 1 mol / L and the concentration of LiFSI was 0.5 mol / L). At 25°C, 18 g of the above electrolyte, 0.92 g of 2-vinylthioethylthiomethyl(trimethoxy)silane, 1.08 g of N-(2-amino-2-oxoethyl)acrylamide (CAS: 2479-62-1), and 0.02 g of azobisisobutyronitrile were stirred until homogeneous. The in-situ solidified electrolyte (denoted as L2) was obtained.

[0069] Preparation Example 3: This preparation example illustrates the preparation of an in-situ solidified electrolyte. Ethyl methyl carbonate (EMC), diethyl carbonate (DEC), and ethylene carbonate (EC) were mixed in a volume ratio of 1:1:1. Then, lithium hexafluorophosphate (LiPF6) and lithium bis(fluorosulfonyl)imide (LiFSI) were added. Finally, 5% by weight of fluoroethylene carbonate (FEC) and 0.5% by weight of lithium difluorooxalate (LiPO2F2) were added. The mixture was stirred thoroughly until homogeneous, yielding an electrolyte (where the concentration of LiPF6 was 1 mol / L and the concentration of LiFSI was 0.5 mol / L). At 25°C, 18 g of the above electrolyte, 0.98 g of 2-vinylthioethylthiomethyl(trimethoxy)silane, 1.02 g of 3-butenylurea (CAS: 75194-72-8), and 0.02 g of azobisisobutyronitrile were stirred until homogeneous. An in-situ solidified electrolyte (denoted as L3) was obtained.

[0070] Preparation Example 4: This preparation example illustrates the preparation of an in-situ solidified electrolyte. Ethyl methyl carbonate (EMC), diethyl carbonate (DEC), and ethylene carbonate (EC) were mixed in a volume ratio of 1:1:1. Then, lithium hexafluorophosphate (LiPF6) and lithium bis(fluorosulfonyl)imide (LiFSI) were added. Finally, 5% by weight of fluoroethylene carbonate (FEC) and 0.5% by weight of lithium difluorooxalate (LiPO2F2) were added. The mixture was stirred thoroughly until homogeneous, yielding an electrolyte (where the concentration of LiPF6 was 1 mol / L and the concentration of LiFSI was 0.5 mol / L). At 25°C, 18 g of the above electrolyte, 0.7 g of mercaptopropyltrimethoxysilane (CAS: 4420-74-0), 1.3 g of dimethylaminopropylacrylamide (CAS: 3845-76-9), and 0.02 g of azobisisobutyronitrile were stirred until homogeneous. The in-situ solidified electrolyte was obtained (denoted as L4).

[0071] Preparation Example 5 This preparation example illustrates the preparation of an in-situ solidified electrolyte. Ethyl methyl carbonate (EMC), diethyl carbonate (DEC), and ethylene carbonate (EC) were mixed in a volume ratio of 1:1:1. Then, lithium hexafluorophosphate (LiPF6) and lithium bis(fluorosulfonyl)imide (LiFSI) were added. Finally, 5% by weight of fluoroethylene carbonate (FEC) and 0.5% by weight of lithium difluorooxalate (LiPO2F2) were added. The mixture was stirred thoroughly until homogeneous, yielding an electrolyte (where the concentration of LiPF6 was 1 mol / L and the concentration of LiFSI was 0.5 mol / L). At 25°C, 18 g of the above electrolyte, 0.91 g of trimethoxy(3-vinylthiopropyl)silane (CAS: 63823-06-3), 1.09 g of 3-butenylurea (CAS: 75194-72-8), and 0.02 g of azobisisobutyronitrile were added. Stir until homogeneous to obtain an in-situ solidified electrolyte (denoted as L5).

[0072] Preparation Example 6: This preparation example illustrates the preparation of an in-situ solidified electrolyte. Ethyl methyl carbonate (EMC), diethyl carbonate (DEC), and ethylene carbonate (EC) were mixed in a volume ratio of 1:1:1. Then, lithium hexafluorophosphate (LiPF6) and lithium bis(fluorosulfonyl)imide (LiFSI) were added. Finally, 5% (by weight of the total electrolyte) of fluoroethylene carbonate (FEC) and 0.5% (by weight of the total electrolyte) of lithium difluorooxalate (LiPO2F2) were added. The mixture was stirred thoroughly until homogeneous, yielding the electrolyte (wherein, the concentration of LiPF6 was 1 mol / L, and the concentration of LiFSI was...). (Concentration 0.5 mol / L); at 25℃, 18 g of the above electrolyte, 1.05 g of 2-vinylthioethylthiomethyl(trimethoxy)silane (CAS: 62811-79-4), 0.95 g of N,N-dimethylacrylamide (CAS: 2680-03-7) and 0.02 g of azobisisobutyronitrile were stirred evenly to obtain an in-situ cured electrolyte (denoted as L6).

[0073] Comparative Preparation Example 1: This comparative preparation example illustrates the preparation of an in-situ solidified electrolyte. Ethyl methyl carbonate (EMC), diethyl carbonate (DEC), and ethylene carbonate (EC) were mixed in a volume ratio of 1:1:1. Then, lithium hexafluorophosphate (LiPF6) and lithium bis(fluorosulfonyl)imide (LiFSI) were added. Finally, 5% by weight of fluoroethylene carbonate (FEC) and 0.5% by weight of lithium difluorooxalate (LiPO2F2) were added. The mixture was stirred thoroughly until homogeneous, yielding an electrolyte (where the concentration of LiPF6 was 1 mol / L and the concentration of LiFSI was 0.5 mol / L). At 25°C, 18 g of the above electrolyte, 0.62 g of allyltrimethoxysilane (CAS: 2551-83-9), 1.38 g of N,N'-methylenebisacrylamide (CAS: 110-26-9), and 0.02 g of azobisisobutyronitrile were added. Stir until homogeneous to obtain an in-situ solidified electrolyte (denoted as DL1).

[0074] Example 1 This example illustrates the preparation of gel electrolytes and lithium-ion batteries using ternary cathode material LiNi. 0.8 Co 0.1 Mn 0.1O2, conductive carbon black (Super-P Li, conductive agent), multi-walled carbon nanotubes (MWCNT, conductive agent), and polyvinylidene fluoride (PVDF, binder) are thoroughly mixed in N-methylpyrrolidone (NMP) at a weight ratio of 97%:1.25%:0.5%:1.25% to obtain a positive electrode slurry; artificial graphite, silicon-oxygen negative electrode, and conductive carbon black (Super-P Li) are then added. Li (conductive agent), single-arm carbon nanotubes (SWCNT, conductive agent), polyacrylic acid (PAA, binder), and styrene-butadiene rubber (SBR, binder) are thoroughly mixed and stirred in deionized water at a weight ratio of 80%:15%:1.5%:1.5%:0.8%:1.2% to obtain a negative electrode slurry. The above positive electrode slurry is coated on a 12μm thick aluminum foil, and the negative electrode slurry is coated on a 6μm thick copper foil. After drying, the cells are rolled, cut, die-cut, and stacked to produce a 10Ah soft-pack dry cell.

[0075] The above-mentioned dry cell was dried and injected with the above-mentioned in-situ solidified electrolyte L1. It was left to stand at 25°C for 48 hours, and then subjected to pressure heating solidification at 0.2 MPa, 60°C and 12 hours. After that, it was formed, sealed and capacity tested to obtain a lithium-ion battery (denoted as B1). Battery B1 contains a gel electrolyte (denoted as S1).

[0076] In S1, the polymer contains repeating units of sulfur-containing siloxane groups (the sulfur-containing siloxane groups have the structure shown in the aforementioned formula (I), wherein R1 contains...) ) and repeating units containing nitrogen groups (nitrogen groups containing ); Sulfur-containing siloxane groups: The molar ratio of nitrogen-containing groups is 3:7, the polymer accounts for 10% of the weight of S1, and the concentration of metal salt in S1 is 1.5 mol / L.

[0077] Example 2 This example illustrates the preparation of gel electrolyte and lithium-ion battery using the same dry cell as in Example 1.

[0078] The dry cell was dried and injected with the above-mentioned in-situ solidified electrolyte L2. It was left to stand at 25°C for 48 hours, and then subjected to pressure heating solidification at 0.2 MPa, 60°C and 12 hours. After that, it was formed, sealed and capacity tested to obtain a lithium-ion battery (denoted as B2). Battery B2 contains a gel electrolyte (denoted as S2).

[0079] In S2, the polymer contains repeating units of sulfur-containing siloxane groups (the sulfur-containing siloxane groups have the structure shown in the aforementioned formula (I), wherein R1 contains...). ) and repeating units containing nitrogen groups (nitrogen groups containing ); Sulfur-containing siloxane groups: The molar ratio of nitrogen-containing groups is 3:7, the polymer accounts for 10% of the weight of S2, and the concentration of metal salt in S2 is 1.5 mol / L.

[0080] Example 3 This example illustrates the preparation of gel electrolyte and lithium-ion battery using the same dry cell as in Example 1.

[0081] The dry cell was dried and injected with the above-mentioned in-situ solidified electrolyte L3. It was left to stand at 25°C for 48 hours, and then subjected to pressure heating solidification at 0.2 MPa, 60°C and 12 hours. After that, it was formed, sealed and tested to obtain a lithium-ion battery (denoted as B3). Battery B3 contains a gel electrolyte (denoted as S3).

[0082] In S3, the repeating unit of the polymer sulfur-containing siloxane group (the sulfur-containing siloxane group has the structure shown in the aforementioned formula (I), wherein R1 contains ) and repeating units containing nitrogen groups (nitrogen groups containing The molar ratio of sulfur-containing siloxane groups to nitrogen-containing groups is 3:7, the polymer accounts for 10% of the weight of S3, and the concentration of metal salt in S3 is 1.5 mol / L.

[0083] Example 4 This example illustrates the preparation of gel electrolyte and lithium-ion battery using the same dry cell as in Example 1.

[0084] The dry cell was dried and injected with the above-mentioned in-situ solidified electrolyte L4. It was left to stand at 25°C for 48 hours, and then subjected to pressure heating solidification at 0.2 MPa, 60°C and 12 hours. After that, it was formed, sealed and capacity tested to obtain a lithium-ion battery (denoted as B4). Battery B4 contains a gel electrolyte (denoted as S4).

[0085] In S4, the polymer contains repeating units of sulfur-containing siloxane groups (the sulfur-containing siloxane groups have the structure shown in the aforementioned formula (I), wherein R1 contains...). ) and repeating units containing nitrogen groups (nitrogen groups containing ); Sulfur-containing siloxane groups: The molar ratio of nitrogen-containing groups is 3:7, the polymer accounts for 10% of the weight of S4, and the concentration of metal salt in S4 is 1.5 mol / L.

[0086] Example 5 This example illustrates the preparation of gel electrolyte and lithium-ion battery using the same dry cell as in Example 1.

[0087] The dry cell is dried and injected with the above-mentioned in-situ solidified electrolyte L5. It is then left to stand at 25°C for 48 hours, followed by pressure heating solidification at 0.2 MPa and 60°C for 12 hours. After that, it undergoes formation, secondary sealing, and capacity testing to obtain a lithium-ion battery (denoted as B5). Battery B2 contains a gel electrolyte (denoted as S5).

[0088] In S5, the polymer contains repeating units of sulfur-containing siloxane groups (the sulfur-containing siloxane groups have the structure shown in the aforementioned formula (I), wherein R1 contains...). ) and repeating units containing nitrogen groups (nitrogen groups containing The molar ratio of sulfur-containing siloxane groups to nitrogen-containing groups is 3:7, the polymer accounts for 10% of the weight of S5, and the concentration of metal salt in S5 is 1.5 mol / L.

[0089] Example 6 This example illustrates the preparation of gel electrolyte and lithium-ion battery using the same dry cell as in Example 1.

[0090] The dry cell was dried and injected with the above-mentioned in-situ solidified electrolyte L5. It was left to stand at 25°C for 48 hours, and then subjected to pressure heating solidification at 0.2 MPa, 60°C and 12 hours. After that, it was formed, sealed and capacity tested to obtain a lithium-ion battery (denoted as B6). Battery B6 contains a gel electrolyte (denoted as S6).

[0091] In S6, the polymer contains repeating units of sulfur-containing siloxane groups (the sulfur-containing siloxane groups have the structure shown in the aforementioned formula (I), wherein R1 contains...) ) and repeating units containing nitrogen groups (nitrogen groups containing The molar ratio of sulfur-containing siloxane groups to nitrogen-containing groups is 3:7, the polymer accounts for 10% of the weight of S5, and the concentration of metal salt in S5 is 1.5 mol / L.

[0092] Comparative Example 1 This comparative example is used to illustrate the preparation of gel electrolyte and lithium-ion battery using the same dry cell as in Example 1.

[0093] The dry cell is dried and injected with the above-mentioned in-situ solidified electrolyte DL1. It is left to stand at 25°C for 48 hours, and then subjected to pressure heating solidification at 0.2 MPa, 60°C and 12 hours. After that, it is formed, sealed and capacity tested to obtain a lithium-ion battery (denoted as DB1). Battery DB1 contains a gel electrolyte (denoted as DS1).

[0094] Test Example A: The above gel electrolytes S1-S6 and DS1 were subjected to volatility test, flame retardant performance test and electrochemical window test respectively. The test process is as follows, and the results are shown in Table 1.

[0095] Volatility test: (1) In an argon glove box, 10g of the above-mentioned in-situ solidified electrolyte samples L1-L6 and DL1 were placed in 20mL black-capped glass bottles, sealed with aluminum-plastic bags, and then heated and solidified in a forced-air oven (solidification temperature was 60℃, solidification time was 12h) to form gel electrolytes S1-S6 and DS1 respectively. During the solidification process, the glass bottles were kept vertical with the bottle mouth facing upwards; (2) After solidification, the total weight of the glass bottle and the gel electrolyte in it was weighed (recorded as m). 0, (3) After the oven temperature drops to room temperature, open the oven door and take out the sample. Weigh the glass bottle and the total weight of the gel electrolyte in it (recorded as m1, g). Calculate the volatilization rate under the condition of 120℃ / 1h according to the following formula: Volatilization rate (%) = (m0-m1) / 10×100%.

[0096] Flame retardant performance test: (1) In an argon glove box, place 2g of the above-mentioned in-situ solidified electrolyte samples L1-L6 and DL1 into 5mL centrifuge tubes, seal them with aluminum-plastic bags, and heat them in a forced-air oven for curing (curing temperature is 60℃, curing time is 12h) to form gel electrolytes S1-S6 and DS1 respectively; (2) After curing, take 0.5g of gel electrolyte sample, break it and spread it evenly in the clasp positive electrode shell, and weigh the total weight of the gel electrolyte sample and the clasp positive electrode shell (recorded as M0, g); (3) Use a blowtorch to continuously spray the gel electrolyte sample to ignite it for 2 seconds. If the sample does not burn, weigh the total weight of the gel electrolyte sample and the clasp positive electrode shell directly (recorded as M1, g); if the sample burns, weigh the total weight of the gel electrolyte sample and the clasp positive electrode shell after the burning is over (recorded as M1). ’ The carbon residue of the gel electrolyte is calculated according to the following formula: Carbon residue (%): (M0-A) / 0.5×100%; where A is M1 or M1 ’ .

[0097] Electrochemical window test: (1) Prepare the above-mentioned in-situ solidified electrolyte L1-L6 and DL1 in an argon glove box, then assemble 4 coin cells (lithium sheet / PE separator / steel sheet) in an argon glove box, inject 90 μL of the in-situ solidified electrolyte to be tested, and after assembly, immerse at 25°C for 4 h. After immersion, heat the coin cells in a forced-air oven to solidify (solidification temperature is 60°C, solidification time is 12 h) to form gel electrolytes S1-S6 and DS1 respectively; (2) Use the linear scanning voltammetry (LSV) in the electrochemical workstation to test the electrochemical window of the gel electrolyte. Test conditions: temperature is 25°C, voltage range is open circuit voltage to 6V, scan rate is 1mV / S, current range is automatic range, and sampling interval is 1mV; (3) After the test, take the current as 1×10-5 The voltage corresponding to A is the electrochemical window of the sample, and the average value of the four samples is taken as the electrochemical window of the gel electrolyte.

[0098] Table 1

[0099] As shown in Table 1, the gel electrolytes S1-S6 provided by this invention exhibit excellent liquid retention and a wide electrochemical window. Under the aforementioned test conditions, the volatility is less than 30%, the electrochemical window is greater than 4.4V, and they possess good high-voltage resistance. These gel electrolytes can promote the formation of a thin and dense CEI, capturing active oxygen released from the positive electrode, while also exhibiting a combustion carbon residue rate higher than 75%, demonstrating excellent flame-retardant properties. Among them, gel electrolytes S1-S3 exhibit particularly outstanding performance advantages in terms of strong liquid retention and good flame-retardant properties.

[0100] Test B: High-voltage cycling performance test, high-temperature cycling performance test, electrochemical window test, hot box test and overcharge safety performance test were conducted on the above gel electrolytes S1-S6 and DS1. The test process is as follows, and the results are shown in Table 2.

[0101] High-voltage cycle performance test: (1) Take a 10Ah dry cell to be injected with electrolyte, inject 20g of the above-mentioned in-situ solidified electrolyte L1-L5 and DL1-DL2 into the glove box respectively, seal it and then carry out aging, solidification (pressure is 0.2MPa, solidification temperature is 60℃, solidification time is 12h), formation and capacity testing in sequence to obtain the battery; (2) Test the high-voltage cycle performance of the above-mentioned battery in a 25℃ explosion-proof oven. The test conditions are as follows: clamp torque is 0.8N·m, 1C constant current and constant voltage charging to 4.3V, cut-off current is 0.05C, stand for 10min, then 1C discharge to 2.5V, cycle until the capacity retention rate is ≤80% (just not higher than 80%) and the test stops.

[0102] High-temperature cycling performance test: (1) Take a 10Ah dry cell to be injected with electrolyte, inject 20g of the above-mentioned in-situ solidified electrolyte L1-L6 and DL1 into the glove box, seal it, and then carry out aging, solidification (pressure is 0.2MPa, solidification temperature is 60℃, solidification time is 12h), formation and capacity testing in sequence to obtain the battery; (2) Test the high-temperature and high-pressure cycling performance of the above batteries in a 45℃ explosion-proof oven. The test conditions are as follows: clamp torque is 0.8N·m, 1C constant current and constant voltage charging to 4.3V, cut-off current is 0.05C, stand for 10min, then 1C discharge to 2.5V, cycle until the capacity retention rate is ≤80% (just not higher than 80%) and the test is stopped.

[0103] Hot box test: (1) Take a 10Ah dry cell to be injected with electrolyte, inject 20g of the above-mentioned in-situ solidified electrolyte L1-L6 and DL1 into the glove box respectively, seal it and then carry out aging, solidification (pressure of 0.2MPa, solidification temperature of 60℃, solidification time of 12h), formation and capacity testing in sequence to obtain the battery; (2) Charge the above batteries in a 25℃ explosion-proof oven respectively under the following conditions: clamping torque of 0.8N·m, constant current and constant voltage charging at 0.33C to 4 .25V, cutoff current 0.05C, stand for 60min; (3) Place the fully charged battery sample with clamp into the explosion-proof box to test the safety performance of the hot box, under the following conditions: monitor the changes in battery voltage and temperature, start the oven heating program: heat from 25℃ to 120℃ at a heating rate of 5℃ / min, hold at 120℃ for 1h, then hold at 10℃ for 1h after each 10℃ increase (heating rate is 5℃ / min), until 200℃ is held at 1h, and the test ends. Record whether each battery sample catches fire or explodes, as well as the temperature and holding time of the fire or explosion.

[0104] Overcharge safety performance test: (1) Take a 10Ah dry cell to be injected with electrolyte, inject 20g of the above-mentioned in-situ solidified electrolyte L1-L6 and DL1 into the glove box respectively, seal it, and then carry out aging, solidification pressure of 0.2MPa, solidification temperature of 60℃, solidification time of 12h, formation and capacity testing in sequence to obtain the battery.

[0105] (2) The batteries were charged in an explosion-proof oven at 25°C under the following conditions: clamp torque 0.8 N·m, constant current and constant voltage charging at 0.33C to 4.25V, cut-off current 0.05C, and left to stand for 60 minutes; (3) The fully charged battery samples with clamps were placed in an explosion-proof box to test the overcharge safety performance under the following conditions: monitoring the battery temperature change, charging the battery at a constant current rate of 1C until the battery catches fire or explodes, or the charging time reaches 1 hour (the battery does not catch fire or explode), and the test is stopped. The overcharge capacity of each battery (denoted as A1) was recorded, and the overcharge SOC ratio was calculated according to the following formula: overcharge SOC ratio (%) = A1 / 10 × 100%.

[0106] Table 2

[0107] As shown in Table 2, the batteries described above, using the gel electrolyte of this invention, exhibited excellent high-temperature and high-pressure stability in the tests. Specifically, they maintained 80% capacity retention for at least 460 cycles at 4.3V high voltage and at least 380 cycles at 45℃. Furthermore, their overcharge SOC ratio was not less than 70%, demonstrating excellent overcharge and thermal safety performance. In contrast, batteries not using the gel electrolyte of this invention showed significantly lower high-temperature and high-pressure stability, overcharge performance, and thermal safety performance compared to batteries using the gel electrolyte of this invention.

[0108] 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 inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A gel electrolyte, characterized in that, The gel electrolyte comprises: a solvent, a polymer, and a metal salt; wherein the polymer is a heterochain polymer whose main chain or side chain contains sulfur-containing siloxane groups and nitrogen-containing groups.

2. The gel electrolyte according to claim 1, wherein, The polymer contains repeating units of sulfur-containing siloxane groups and repeating units of nitrogen-containing groups; preferably, the sulfur-containing siloxane groups have the structure shown in formula (I); Formula (I); wherein R1 is a chain segment containing the structure shown in Formula (II) or Formula (III), and the two ends of the chain segment with the structure shown in Formula (II) or Formula (III) are respectively connected to straight-chain alkyl or branched alkyl with the number of carbon atoms between 0 and 10; Formula (II); Formula (III); preferably, the nitrogen-containing group is selected from amide or urea; preferably, the nitrogen atom in the nitrogen-containing group is bonded to at least one hydrogen atom.

3. The gel electrolyte according to claim 1 or 2, wherein, In the polymer, the molar ratio of the sulfur-containing siloxane group to the nitrogen-containing group is 1:(0.1-10), preferably 1:(2-10).

4. The gel electrolyte according to claim 2, wherein, In formula (I), R1 is a chain segment containing the structure shown in formula (III); and / or, the repeating unit of the nitrogen-containing group contains at least two nitrogen atoms, and each nitrogen atom is connected to at least one hydrogen atom; and / or, the polymer accounts for 2-30% by weight in the gel electrolyte, preferably 2-15%; and / or, the concentration of the metal salt in the gel electrolyte is 0.5-5 mol / L, preferably 1-3 mol / L.

5. The gel electrolyte according to any one of claims 1-4, wherein, The metal salt is selected from at least one of LiPF6, LiFSI, LiTFSI, LiDFOB, LiBF4, LiBOB, LiPO2F2, and LiFTFSI; and / or, the solvent is selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, dimethyl carbonate, succinate, diethyl carbonate, 1,2-dimethoxyethane, 1,3-dioxolane, fluoroethylene carbonate, ethyl acetate, propyl formate, propyl propionate, and γ-butyrolactone.

6. An in-situ solidified electrolyte, characterized in that, The in-situ cured electrolyte comprises: a sulfur-containing silane coupling agent, a double-bonded monomer with a nitrogen-containing group, an electrolyte, and an initiator.

7. The in-situ solidified electrolyte according to claim 6, wherein, The sulfur-containing silane coupling agent satisfies the general chemical formula: YR-SiX3; X is selected from -OCH3, -OCH2CH3, -OCH(CH3)2 or -OCOCH3; wherein, when Y is selected from -SH, R is selected from CO-C with or without +2 valence sulfur. 10 Alkyl groups, or C0-C 10 Alkyl thiols, or C0-C 10 Alkenyl thiols; when Y is selected from -CH=CH2 or -C(CH3)=CH2; R is selected from CO-C containing a +2 valence sulfur element. 10 Alkyl groups, or C0-C 10 Alkyl thiols, or C0-C 10 alkenyl thiols.

8. The in-situ solidified electrolyte according to claim 7, wherein, The sulfur-containing silane coupling agent contains at least two sulfur atoms; and / or, the sulfur-containing silane coupling agent is selected from mercaptopropyltrimethoxysilane, methimoxytrimethoxysilane, 2-[(trimethoxysilane)methyl]-1,3-propanedithiol, (mercaptomethyl)triethoxysilane, mercaptopropyltriethoxysilane, methimoxytributoxysilane, 1-trimethoxysilylpropane-2-thiol, 1-triethoxysilylethane-1,2-dithiol, and 2-vinylthioethyl(triethoxy)silane. At least one of the following: alkyl, 2-vinylthioethylthiomethyl(trimethoxy)silane, trimethoxy(2-propenylthiomethyl)silane, 1-trimethoxysilylmethylthio-1-buten-3-yne, 2-trimethoxysilyl ethanethiol, trimethoxy(3-vinylthiopropyl)silane, 1-(vinylthioethyl)triethoxysilane, 3-(2-propenylthioethylthio)propyltrimethoxysilane, and 3-(2-vinylthioethylthio)propyltrimethoxysilane.

9. The in-situ solidified electrolyte according to any one of claims 6-8, wherein, The nitrogen-containing group in the double-bonded monomer with a nitrogen-containing group is selected from amide or urea groups; preferably, the double-bonded monomer with a nitrogen-containing group contains at least two nitrogen atoms, and each nitrogen atom is bonded to at least one hydrogen atom; preferably, the double-bonded monomer with a nitrogen-containing group is selected from at least one of methacrylamide ethyl ethylene urea, N-(isobutoxymethyl)acrylamide, 2-(1,2-cyclohexanedicarboxyimide)ethyl acrylate, N-vinylcaprolactam, diacetone acrylamide, 2-(tert-butylamino)methyl methacrylate, ethyl methacrylate ethoxylate, dimethylaminopropyl acrylamide, a mixture of diurea dimethacrylate isomers, N,N'-methylenebisacrylamide, N-vinylformamide, N-isopropylmethylacrylamide, 1-allylhydantoin, N-(1,1,3,3-tetramethylbutyl)acrylamide, 3-butenyl urea, and N-(2-amino-2-oxoethyl)acrylamide.

10. The in-situ solidified electrolyte according to any one of claims 6-9, wherein, The electrolyte comprises a metal salt and a solvent; preferably, the metal salt is selected from at least one of LiPF6, LiFSI, LiTFSI, LiDFOB, LiBF4, LiBOB, LiPO2F2, and LiFTFSI; preferably, the solvent is selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, dimethyl carbonate, succinate, diethyl carbonate, 1,2-dimethoxyethane, 1,3-dioxolane, fluoroethylene carbonate, ethyl acetate, propyl formate, propyl propionate, and γ-butyrolactone; preferably, the concentration of the metal salt in the electrolyte is 1-3 mol / L.

11. The in-situ solidified electrolyte according to any one of claims 6-10, wherein, The weight ratio of the sulfur-containing silane coupling agent to the double-bonded monomer with nitrogen-containing groups is (0.1-10):1; and / or, the weight ratio of the sum of the masses of the sulfur-containing silane coupling agent and the double-bonded monomer with nitrogen-containing groups to the weight of the in-situ cured electrolyte is (2-30):

100.

12. A gel electrolyte, characterized in that, The gel electrolyte is formed by in-situ polymerization of the in-situ solidified electrolyte as described in any one of claims 6-11.

13. The gel electrolyte according to claim 12, wherein, The conditions for the in-situ polymerization reaction include: a temperature of 40-90℃, a pressure of 0.05-0.6MPa, and a time of 4-18h.

14. A lithium-ion battery, characterized in that, The lithium-ion battery contains the gel electrolyte as described in any one of claims 1-5 and 12-13.

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