A Lithium-Ion Electrolyte, Gel Polymer Electrolyte and Lithium-Ion Battery

Abstract

The present invention relates to a lithium-ion electrolyte, a gel polymer electrolyte and a lithium-ion battery. In order to solve the problems of poor liquid retention and poor cycling performance of the gel polymer electrolyte, the present invention provides a lithium-ion electrolyte, which comprises a lithium salt, an organic solvent, a precursor and an additive. The additive comprises one or two of zero-dimensional carbon nanomaterials and quasi-zero-dimensional carbon nanomaterials, and a plasticizer. The lithium-ion electrolyte of the present invention has good liquid retention after polymerization, can maintain good interfacial compatibility with the electrode, improve the interfacial resistance, and enhance the room-temperature cycling performance of the lithium-ion battery.

Description

Technical Field

[0001] The present invention relates to a lithium-ion electrolyte, a gel polymer electrolyte, and a lithium-ion battery. Background Art

[0002] Lithium ion batteries (LIBs) have the advantages of high working voltage, high energy density, long cycle life, environmental friendliness, and low self-discharge, and can be used as portable energy storage devices in electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, industries, and smart grids, and have broad application prospects in future use.

[0003] As one of the extremely important components in LIBs, the electrolyte has a great impact on the safety and electrochemical performance of LIBs. Traditional electrolyte materials are mainly organic liquid electrolytes supplemented by others. However, organic liquid electrolytes are prone to problems such as leakage and gas expansion, which can cause a series of safety problems. Solid electrolytes have good safety, but have poor contact with electrodes, resulting in high interfacial impedance, and most solid electrolytes have low room-temperature ionic conductivity, which cannot meet the needs of lithium-ion batteries. Gel polymer electrolytes are electrolytes formed by adding corresponding plasticizers to all-solid polymer electrolytes. This combination has both the cohesion of solids and the diffusivity of liquids. It combines the excellent properties of polymer matrices (such as mechanical stability, flexibility, and non-leakage) with the excellent ionic conductivity of liquid organic electrolytes, and has significant commercial prospects.

[0004] Although gel polymer electrolytes have many excellent properties, they also have low mechanical strength and are difficult to resist the damage of lithium dendrites during battery use. Chinese Patent CN201910732788.8 discloses the use of graphene quantum dots as additives to modify the electrolyte. Without affecting lithium-ion transport, as nucleation sites, it guides the uniform nucleation and growth deposition of lithium, inhibits the dendritic growth during the charge and discharge cycle of lithium metal electrodes, and eliminates the hidden danger of short circuit. However, adding polymers and graphene quantum dots to conventional electrolytes cannot improve the electrochemical performance of electrodes, especially those using silicon anodes, due to their volume expansion. Moreover, due to the polymers, the initial capacity of lithium-ion batteries will also decrease and the cycle performance will deteriorate. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a lithium-ion electrolyte, and the gel polymer electrolyte prepared therefrom has good liquid retention and better room-temperature cycle performance.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A lithium-ion electrolyte, the lithium-ion electrolyte comprising a lithium salt, an organic solvent, a precursor, and an additive, the additive comprising one or both of zero-dimensional carbon nanomaterials and quasi-zero-dimensional carbon nanomaterials, and a plasticizer.

[0008] Preferably, the precursor is selected from one or more of methacrylate, vinylene carbonate (VC), acrylonitrile (AN), vinyl acetate (VAC), styrene (ST), polyethylene oxide (PEO), polyphenylene oxide (PPO), polyoxymethylene (POM), polyvinyl acetate (PVA), polyethyleneimine (PEI), polyethylene succinate, polyoxetane, poly-β-propiolactone, epichlorohydrin, poly-N-propylaziridine, polyalkenepolysulfide, polyvinylidene fluoride (PVDF), methyl acrylate (MA), acrylamide (AM), methyl 2-hydroxyacrylate, trifluoroethyl acrylate (TFMA), polyethylene glycol phenyl ether acrylate (PEGPEA), polyethylene glycol diacrylate (PEGDA), polyethylene glycol diglycidyl ether (PEGDE), ethoxylated trimethylolpropane triacrylate (ETPTA), polycyano polyvinyl alcohol (PVA-CN), 1,3-dioxolane (DOL), 1,3,5-trioxane, 1,4-dioxane, tetrahydrofuran (THF), polyvinyl formal (PVFM).

[0009] Preferably, the precursor accounts for 1-5% of the total mass of the lithium-ion electrolyte, such as 1%, 1.5%, 2%, 2.5%, 3%, 4%, 5%, etc.

[0010] Preferably, the plasticizer is selected from one or more of fluorobenzene, ethyl acetate, methyl phthalate.

[0011] Preferably, the plasticizer accounts for 3-12% of the total mass of the lithium-ion electrolyte, such as 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, etc.

[0012] Preferably, when the lithium salt does not include LiPF6 and / or LiBF4, the lithium-ion electrolyte further comprises an initiator; when the lithium salt includes LiPF6 and / or LiBF4, the lithium-ion electrolyte selectively adds an initiator. LiPF6 can be partially decomposed to form PF5 after being stored under certain conditions, and LiBF4 can be partially decomposed to produce BF3 after being stored under certain conditions. PF5 and BF3 can respectively serve as initiators for forming polymers, causing the electrolyte to change from a liquid state to a gel state.

[0013] Preferably, the initiator is selected from one or more of azo initiators, peroxide initiators, redox initiators, cationic polymerization initiators, and anionic polymerization initiators.

[0014] Further preferably, the azo initiator includes one or both of azobisisobutyronitrile and dimethyl azobisisobutyrate; the peroxide initiator includes benzoyl peroxide; the initiator for cationic polymerization includes one or more of BF3, PF5, AlCl3, Al(CF3SO3)3, Sn(CF3SO3)2; the initiator for anionic polymerization includes one or more of alkali metals, organic compounds of alkali metals and alkaline earth metals, tertiary amines, and nucleophiles.

[0015] Preferably, the additive further includes one or more of benzenesulfonamide derivatives, and the structural formula of the benzenesulfonamide derivative is wherein, R1 is selected from any one of F, alkyl, and fluoroalkyl, and R2 is selected from any one of H, F, alkyl, and fluoroalkyl.

[0016] Further preferably, the benzenesulfonamide derivative includes N-methyl-N-nitrosotoluenesulfonamide (CAS: 80-11-5).

[0017] Preferably, the benzenesulfonamide derivative accounts for 0.05-5% of the total mass of the lithium ion electrolyte, such as 0.05%, 0.1%, 0.5%, 1%, 1.5%, 2%, 3%, 4%, 5%, etc.

[0018] Preferably, the organic solvent is selected from one or more of ethylene carbonate, fluoroethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, 1,4-butyrolactone, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, acetonitrile, adiponitrile, succinonitrile, glutaronitrile, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, dimethyl sulfone, sulfolane, and trimethyl phosphate.

[0019] According to some preferred embodiments, the organic solvent includes ethylene carbonate, fluoroethylene carbonate, and ethyl methyl carbonate. When the precursor is selected from polymers (such as PVA-CN, etc.), the solubility of the polymer in the system of this organic solvent is poor and the dissolution requires a long time (more than 2 h). As a preference, the organic solvent further includes N,N-dimethylformamide. By first dissolving the polymer in N,N-dimethylformamide and then mixing it with the system of this organic solvent, the dissolution time of the polymer can be greatly shortened.

[0020] Preferably, the organic solvent accounts for 70-85% of the total mass of the lithium ion electrolyte, such as 70%, 72%, 74%, 76%, 78%, 80%, 82%, etc.

[0021] Preferably, the lithium salt includes one or more of LiTFSI, LiPF6, LiBF4, LiBOB, LiBC2O4F2, LiClO4, LiCF3SO3, LiN(FSO2)2, LiN(CF3SO2)2.

[0022] Preferably, the lithium salt accounts for 10-20% of the total mass of the lithium-ion electrolyte, such as 10%, 11%, 12%, 13%, 15%, 16%, 17%, 18%, 19%, 20%, etc.

[0023] Preferably, the zero-dimensional carbon nanomaterial includes one or more of fullerenes, nanodiamonds, carbon nano-onions.

[0024] Preferably, the quasi-zero-dimensional carbon nanomaterial includes graphene quantum dots and / or carbon dots.

[0025] Preferably, one or two of the zero-dimensional carbon nanomaterial and the quasi-zero-dimensional carbon nanomaterial account for 0.05-0.5% of the total mass of the lithium-ion electrolyte, such as 0.05%, 0.1%, 0.15%, 0.2%, 0.3%, 0.4%, 0.5%, etc.

[0026] The present invention also provides a gel polymer electrolyte, which is formed by reacting the lithium-ion electrolyte as described above.

[0027] Preferably, the reaction includes standing at a temperature of 55-65°C for 20-28 hours to convert the lithium-ion electrolyte from a liquid state to a gel polymer electrolyte in a gel state.

[0028] The present invention also provides a lithium-ion battery, which includes a positive electrode, a negative electrode, a separator, and the gel polymer electrolyte as described above.

[0029] Preferably, the material of the positive electrode is a ternary material, and the ternary material includes but is not limited to NCM811.

[0030] Preferably, the material of the negative electrode is silicon carbon, and the silicon carbon includes but is not limited to SiOx-C.

[0031] Due to the application of the above technical solutions, the present invention has the following advantages compared with the prior art:

[0032] The lithium-ion electrolyte of the present invention has good liquid retention after polymerization, can maintain good interfacial compatibility with the electrode, improve the interfacial resistance, and improve the room-temperature cycling performance of the lithium-ion battery. Detailed implementation manners

[0033] Although gel polymer electrolytes have many excellent properties, their mechanical strength is low and it is difficult to resist the damage of lithium dendrites during battery use. Adding graphene quantum dots to the electrolyte can inhibit dendrite growth during the charge and discharge cycles of lithium metal electrodes and eliminate the hidden danger of short circuits. However, the cycle performance of the battery cannot be improved. The applicant adjusts the formulation of the lithium-ion electrolyte to provide a lithium-ion electrolyte that has good liquid retention after polymerization, can maintain good interfacial compatibility with the electrodes, improve the interfacial resistance, and thus enhance the cycle performance of the battery. The following further describes the solution of the present application.

[0034] The present invention provides a lithium-ion electrolyte, which includes a lithium salt, an organic solvent, a precursor, and an additive. The additive includes one or two of zero-dimensional carbon nanomaterials and quasi-zero-dimensional carbon nanomaterials, and a plasticizer.

[0035] According to some specific and preferred embodiments, a lithium-ion electrolyte includes:

[0036] A lithium salt, which is LiPF6;

[0037] An organic solvent, which includes ethylene carbonate, fluoroethylene carbonate, and ethyl methyl carbonate;

[0038] A precursor, which is PVA-CN;

[0039] An additive, which includes one or two of zero-dimensional carbon nanomaterials and quasi-zero-dimensional carbon nanomaterials, and a plasticizer.

[0040] Further, the additive further includes one or more of benzenesulfonamide derivatives, and the structural formula of the benzenesulfonamide derivative is

[0041] wherein, R1 is selected from any one of F, alkyl, and fluoroalkyl, and R2 is selected from any one of H, F, alkyl, and fluoroalkyl.

[0042] The following further describes the present invention with reference to the embodiments. However, the present invention is not limited to the following embodiments. The implementation conditions adopted in the embodiments can be further adjusted according to different requirements of specific use, and the implementation conditions not specified are conventional conditions in the industry. The technical features involved in each embodiment of the present invention can be combined with each other as long as they do not conflict with each other.

[0043] A battery includes a positive electrode, a negative electrode, a separator, and a gel polymer electrolyte. The preparation methods of the positive electrode, the negative electrode, the separator, and the gel polymer electrolyte are as follows.

[0044] Preparation of the cathode of ternary material (NCM811): Weigh the cathode active material NCM811, conductive agent Super-P, and binder PVDF (polyvinylidene fluoride) in a ratio of 8:1:1, add them to an appropriate solvent, and mix well to form a uniform slurry to make the cathode active material layer; clean the cathode current collector, then evenly coat the cathode active material layer on the surface of the cathode current collector, and immediately place it in a vacuum drying oven at 60 °C for 12 h for standby;

[0045] Preparation of the separator: Place the PP (polypropylene) / PE (polyethylene) / PP three-layer separator in a vacuum drying oven for standby;

[0046] Preparation of the silicon-carbon (SiOx-C) anode: Weigh the anode active material SiOx-C, conductive agent Super-P, and binder LiPAA in a ratio of 92:2:6, add them to an appropriate solvent, and mix well to form a uniform slurry to make the anode active material layer; clean the anode current collector, then evenly coat the anode active material layer on the surface of the anode current collector, and immediately place it in a vacuum drying oven at 60 °C for 12 h for standby;

[0047] Seal the electrolytes prepared in the following examples and comparative examples in a glass bottle, leave them at 60 °C for 24 h, and observe the appearance and morphology of the electrolytes.

[0048] Prepare the electrolytes according to the following examples and comparative examples, and inject the electrolytes prepared in the following examples and comparative examples into the full cells assembled with the above materials (the assembly method refers to the battery assembly method in the prior art, and the present invention does not make specific limitations) for testing. First, charge the battery at a constant current of 0.1C to 4.2V at 25 °C, leave it for 15 min, discharge it at a constant current to 2.75V, and then perform the second sealing; leave the battery at 60 °C for 24 h; charge the battery at a constant current of 0.2C to 4.2V at 25 °C, leave it for 15 min, discharge it at a constant current of 0.2C to 2.75V, and cycle 5Z; charge the battery at a constant current of 0.5C to 4.2V at 25 °C, leave it for 15 min, discharge it at a constant current of 1.0C to 2.75V, and cycle 300Z.

[0049] Example 1

[0050] Mix 18.64 g of ethylene carbonate (EC), 4.49 g of fluoroethylene carbonate (FEC), 51.7 g of ethyl methyl carbonate (EMC), and 10 g of ethyl acetate, add 15.17 g of electrolyte salt (LiPF6) to the above mixed solution and stir well; then add 2 g of PVA-CN (polycyano polyvinyl alcohol) and 0.15 g of graphene quantum dots to this solution.

[0051] Example 2

[0052] Mix 18.64 g of ethylene carbonate (EC), 4.49 g of fluoroethylene carbonate (FEC), 56.7 g of ethyl methyl carbonate (EMC), and 5 g of fluorobenzene. Add 15.17 g of electrolyte salt (LiPF6) to the above mixed solution and stir evenly. Then add 2 g of PVA-CN and 0.15 g of graphene quantum dots to this solution.

[0053] Example 3

[0054] Mix 18.64 g of ethylene carbonate (EC), 4.49 g of fluoroethylene carbonate (FEC), 56.7 g of ethyl methyl carbonate (EMC), and 5 g of dimethyl phthalate. Add 15.17 g of electrolyte salt (LiPF6) to the above mixed solution and stir evenly. Then add 2 g of PVA-CN and 0.15 g of graphene quantum dots to this solution.

[0055] Example 4

[0056] Mix 18.64 g of ethylene carbonate (EC), 4.49 g of fluoroethylene carbonate (FEC), 56.7 g of ethyl methyl carbonate (EMC), and 5 g of dimethyl phthalate. Add 15.17 g of electrolyte salt (LiPF6) to the above mixed solution and stir evenly. Then add 2 g of PVA-CN and 0.15 g of carbon dots to this solution.

[0057] Example 5

[0058] Mix 18.64 g of ethylene carbonate (EC), 4.49 g of fluoroethylene carbonate (FEC), 51.7 g of ethyl methyl carbonate (EMC), and 10 g of ethyl acetate. Add 15.17 g of electrolyte salt (LiPF6) to the above mixed solution and stir evenly. Then add 2 g of PVA-CN, 0.15 g of graphene quantum dots, and 1 g of N-methyl-N-nitrosotoluenesulfonamide to this solution.

[0059] Example 6

[0060] Mix 18.64 g of ethylene carbonate (EC), 4.49 g of fluoroethylene carbonate (FEC), 51.7 g of ethyl methyl carbonate (EMC), and 10 g of ethyl acetate. Add 15.17 g of electrolyte salt (LiPF6) to the above mixed solution and stir evenly. Then add 2 g of PVA-CN, 0.15 g of graphene quantum dots, and 2 g of N-methyl-N-nitrosotoluenesulfonamide to this solution.

[0061] Comparative Example 1

[0062] Mix 18.64 g of ethylene carbonate (EC), 4.49 g of fluoroethylene carbonate (FEC), and 61.7 g of ethyl methyl carbonate (EMC), and add 15.17 g of electrolyte salt (LiPF6) to the above mixed solution and stir evenly.

[0063] Comparative Example 2

[0064] Mix 18.64 g of ethylene carbonate (EC), 4.49 g of fluoroethylene carbonate (FEC), and 61.7 g of ethyl methyl carbonate (EMC), and add 15.17 g of electrolyte salt (LiPF6) to the above mixed solution and stir evenly; then add 2 g of PVA-CN and 0.15 g of graphene quantum dots to this solution.

[0065] Comparative Example 3

[0066] Mix 18.64 g of ethylene carbonate (EC), 4.49 g of fluoroethylene carbonate (FEC), and 61.7 g of ethyl methyl carbonate (EMC), and add 15.17 g of electrolyte salt (LiPF6) to the above mixed solution and stir evenly; then add 3.0 g of PVA-CN and 0.15 g of graphene quantum dots to this solution.

[0067] Comparative Example 4

[0068] Mix 18.64 g of ethylene carbonate (EC), 4.49 g of fluoroethylene carbonate (FEC), and 61.7 g of ethyl methyl carbonate (EMC), and add 15.17 g of electrolyte salt (LiPF6) to the above mixed solution and stir evenly; then add 2.0 g of PVA-CN and 0.05 g of graphene quantum dots to this solution.

[0069] Comparative Example 5

[0070] Mix 18.64 g of ethylene carbonate (EC), 4.49 g of fluoroethylene carbonate (FEC), and 61.7 g of ethyl methyl carbonate (EMC), and add 15.17 g of electrolyte salt (LiPF6) to the above mixed solution and stir evenly; then add 2.0 g of PVA-CN and 0.1 g of graphene quantum dots to this solution.

[0071] Comparative Example 6

[0072] Mix 18.64 g of ethylene carbonate (EC), 4.49 g of fluoroethylene carbonate (FEC), 51.7 g of ethyl methyl carbonate (EMC), and 10 g of ethyl acetate, and add 15.17 g of electrolyte salt (LiPF6) to the above mixed solution and stir evenly; then add 2.0 g of PVA-CN to this solution.

[0073] Comparative Example 7

[0074] 18.64 g of ethylene carbonate (EC), 4.49 g of fluoroethylene carbonate (FEC), 51.7 g of ethyl methyl carbonate (EMC) and 10 g of ethyl acetate were mixed, and 15.17 g of electrolyte salt (LiODFB) was added to the above mixed solution and stirred evenly; 2 g of PVA-CN (polycyano polyvinyl alcohol) and 0.15 g of graphene quantum dots were further added to this solution.

[0075] The performances of the electrolytes and batteries prepared in the above examples and comparative examples are shown in Table 1 below.

[0076] Table 1

[0077] Morphology after the electrolyte is left standing at 60°C for 24 h Capacity retention rate / % after 300 cycles at 25°C Example 1 Polymerization, no electrolyte leakage; 89 Example 2 Polymerization, no electrolyte leakage; 84 Example 3 Polymerization, no electrolyte leakage; 79 Example 4 Polymerization, no electrolyte leakage; 91 Example 5 Polymerization, no electrolyte leakage; 92 Example 6 Polymerization, no electrolyte leakage; 95 Comparative Example 1 Liquid 54 Comparative Example 2 Polymerization, with electrolyte leakage; 48 Comparative Example 3 Polymerization, with electrolyte leakage; 44 Comparative Example 4 Polymerization, with electrolyte leakage; 42 Comparative Example 5 Polymerization, with electrolyte leakage; 48 Comparative Example 6 Polymerization, with electrolyte leakage; 47 Comparative Example 7 No polymerization /

[0078] The inventor found in the research that PVA-CN has poor solubility in conventional electrolytes and requires stirring for more than 2 h to dissolve. The inventor dissolved PVA-CN in N,N-dimethylformamide. For example, 2 g of PVA-CN was dissolved in 10 g of N,N-dimethylformamide and it could be completely dissolved in about 30 min, greatly shortening the dissolution time of PVA-CN; then the N,N-dimethylformamide solution of the dissolved PVA-CN was added to the electrolyte as a raw material. The experimental results showed that the effects of the electrolytes prepared by using the N,N-dimethylformamide solution of PVA-CN as a raw material and directly using PVA-CN as a raw material were quite equivalent.

[0079] The above has made a detailed description of the present invention, aiming to enable those skilled in this field to understand the content of the present invention and implement it. However, it should not be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A lithium-ion electrolyte, the lithium-ion electrolyte comprising a lithium salt, an organic solvent, a precursor, and an additive, characterized in that, The precursor is selected from one or more of methacrylate, vinylene carbonate, acrylonitrile, vinyl acetate, styrene, polyethylene oxide, polyphenylene ether, polyoxymethylene, polyvinyl acetate, polyethyleneimine, polyethylene succinate, polyoxetane, poly-β-propiolactone, epichlorohydrin, poly-N-propylaziridine, polysulfide polyolefin, polyvinylidene fluoride, methyl acrylate, acrylamide, methyl 2-hydroxyacrylate, trifluoroethyl acrylate, polyethylene glycol phenyl ether acrylate, polyethylene glycol diacrylate, polyethylene glycol diglycidyl ether, ethoxylated trimethylolpropane triacrylate, 1,3-dioxolane, 1,3,5-trioxane, 1,4-dioxane, tetrahydrofuran, and polyvinyl formal. The precursor accounts for 1-5% of the total mass of the lithium ion electrolyte. The additive includes one or two of zero-dimensional carbon nanomaterials and quasi-zero-dimensional carbon nanomaterials, a plasticizer, and one or more of benzenesulfonamide derivatives. One or two of the zero-dimensional carbon nanomaterials and quasi-zero-dimensional carbon nanomaterials account for 0.05 to 0.5% of the total mass of the lithium-ion electrolyte. The plasticizer is fluorobenzene and / or ethyl acetate, and the plasticizer accounts for 3 to 12% of the total mass of the lithium-ion electrolyte; the structural formula of the benzenesulfonamide derivative is , where R1 is selected from any one of F, alkyl, and fluoroalkyl, and R2 is selected from any one of H, F, alkyl, and fluoroalkyl. When the lithium salt does not include LiPF6 and / or LiBF4, the lithium ion electrolyte further includes an initiator. When the lithium salt includes LiPF6 and / or LiBF4, the initiator is selectively added to the lithium ion electrolyte. The lithium salt accounts for 10-20% of the total mass of the lithium ion electrolyte.

2. The lithium-ion electrolyte according to claim 1, wherein The initiator is selected from one or more of azo initiators, peroxide initiators, redox initiators, cationic polymerization initiators, and anionic polymerization initiators.

3. The lithium-ion electrolyte according to claim 2, characterized in that, The azo initiators include one or both of azobisisobutyronitrile and dimethyl azobisisobutyrate. The peroxide initiator includes dibenzoyl peroxide. The cationic polymerization initiators include one or several of BF3, PF5, AlCl3, Al(CF3SO3)3, and Sn(CF3SO3)2. The anionic polymerization initiators include one or more of alkali metals, organic compounds of alkali metals and alkaline earth metals, tertiary amines, and nucleophiles.

4. The lithium ion electrolyte according to claim 1, characterized in that, The benzenesulfonamide derivative includes N-methyl-N-nitrosotoluenesulfonamide; and / or The benzenesulfonamide derivative accounts for 0.05-5% of the total mass of the lithium ion electrolyte.

5. The lithium-ion electrolyte according to claim 1, characterized in that, The organic solvent is selected from one or more of ethylene carbonate, fluoroethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, 1,4-butyrolactone, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, acetonitrile, adiponitrile, succinonitrile, glutaronitrile, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, dimethyl sulfone, sulfolane, and trimethyl phosphate; and / or the organic solvent accounts for 70-85% of the total mass of the lithium ion electrolyte.

6. The lithium-ion electrolyte according to claim 1, wherein The lithium salt includes one or more of LiTFSI, LiPF6, LiBF4, LiBOB, LiBC2O4F2, LiClO4, LiCF3SO3, LiN(FSO2)2, and LiN(CF3SO2)2.

7. The lithium-ion electrolyte according to claim 1, characterized in that, The zero-dimensional carbon nanomaterials include one or more of fullerenes, nanodiamonds, and carbon nano-onions; the quasi-zero-dimensional carbon nanomaterials include graphene quantum dots and / or carbon dots.

8. A gel polymer electrolyte, characterized in that, The gel polymer electrolyte is formed by reacting the lithium-ion electrolyte according to any one of claims 1 to 7.

9. The gel polymer electrolyte according to claim 8, characterized in that, The reaction includes leaving it to stand for 20 to 28 hours at a temperature of 55 to 65 °C to convert the lithium-ion electrolyte from a liquid state to a gel polymer electrolyte in a gel state.

10. A lithium-ion battery, characterized in that, The lithium-ion battery includes a positive electrode, a negative electrode, a separator, and the gel polymer electrolyte according to claim 8 or 9.

11. The lithium-ion battery according to claim 10, wherein, The material of the positive electrode is a ternary material, and the material of the negative electrode is silicon carbide.

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