WO2022095777A1 - 一种非水电解液及电池 - Google Patents

一种非水电解液及电池 Download PDF

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WO2022095777A1
WO2022095777A1 PCT/CN2021/126977 CN2021126977W WO2022095777A1 WO 2022095777 A1 WO2022095777 A1 WO 2022095777A1 CN 2021126977 W CN2021126977 W CN 2021126977W WO 2022095777 A1 WO2022095777 A1 WO 2022095777A1
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group
lithium
electrolyte
battery
solvent
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PCT/CN2021/126977
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English (en)
French (fr)
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邓永红
张光照
谢伟东
胡时光
吴成英
江丽军
邓晓岚
王朝阳
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三明市海斯福化工有限责任公司
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0567—Liquid materials characterised by the additives
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0568—Liquid materials characterised by the solutes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0569—Liquid materials characterised by the solvents
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the invention belongs to the technical field of secondary batteries, and particularly relates to a non-aqueous electrolyte and a battery.
  • Electrolyte is known as the "blood” in lithium-ion batteries, and plays a crucial role in the development of electrode material capacity, battery cycle stability, and battery safety in lithium-ion batteries.
  • ether electrolytes represented by ethylene glycol dimethyl ether (DME) and 1,3-cyclopentane (DOL) react slowly with lithium metal and show good stability to lithium metal, so they have been favored by many scholars. For the study of lithium metal batteries.
  • lithium polysulfide has good solubility in ether electrolytes and does not react with solvents, so ether electrolytes are also commonly used in lithium-sulfur batteries.
  • the classic formula is 1M bis-trifluoromethanesulfonimide. Lithium (LiTFSI) was dissolved in DME/DOL (1:1 v/v), while adding 1-2% LiNO3 as an additive.
  • ether electrolyte system has good stability to lithium metal and can alleviate the growth of lithium dendrites, its oxidative decomposition potential is low, which makes it difficult to meet the needs of high-voltage cathode materials (such as ternary cathode materials NCM, sharp spar nickel lithium manganate and other cathode materials).
  • cathode materials such as ternary cathode materials NCM, sharp spar nickel lithium manganate and other cathode materials.
  • ether electrolytes like ester electrolytes, are flammable, which brings a series of safety hazards to lithium-ion battery packs.
  • sulfone compound additives such as sulfonamide compounds or sulfonate ester compounds
  • electrochemical performance of the battery can be improved to a lesser extent by adding sulfone compounds to the electrolyte, but the existing The sulfone compound additive does not have a good effect on improving the oxidation resistance of the electrolyte.
  • the present invention provides a non-aqueous electrolyte and a battery.
  • the present invention provides a non-aqueous electrolyte solution, comprising an electrolyte and a solvent, and the solvent includes a compound shown in Structural Formula 1:
  • R 1 is selected from fluoroalkyl, fluoroalkoxy or fluoroalkenyl
  • R 2 is selected from or single bond, n is 1 or 2;
  • R is selected from hydrocarbyl, alkoxy, alkenyl, alkenyloxy, aryl, aryloxy or R 4 is selected from hydrocarbon group, alkoxy group, alkenyl group, alkenyloxy group, aryl group, aryloxy group, ether group or polyether chain, R 5 is selected from or a single bond, m is 1 or 2, and R 6 is selected from fluoroalkyl, fluoroalkoxy or fluoroalkenyl.
  • the number of carbon atoms of R 1 is 1-10, and when R 3 is selected from hydrocarbon group, alkoxy group, alkenyl group, alkenyloxy group, aryl group or aryloxy group, the number of carbon atoms of R 3 is 1-10 , the number of carbon atoms of R 4 is 1-10, and the number of carbon atoms of R 6 is 1-10.
  • R 1 is selected from fluoroalkyl, fluoroalkoxy or fluoroalkenyl
  • R 2 is selected from n is 1 or 2
  • R3 is selected from hydrocarbyl, alkoxy, alkenyl, alkenyloxy, aryl or aryloxy.
  • R 1 is selected from fluoroalkyl, fluoroalkoxy or fluoroalkenyl
  • R 2 is a single bond
  • R 3 is selected from hydrocarbyl, alkoxy, alkenyl, alkenyloxy, aryl or Aryloxy.
  • R 1 is selected from fluoroalkyl, fluoroalkoxy or fluoroalkenyl
  • R 2 is selected from n is 1 or 2
  • R 3 is selected from R 4 is selected from hydrocarbyl, alkoxy, alkenyl, alkenyloxy, aryl or aryloxy
  • R 5 is selected from m is 1 or 2
  • R 6 is selected from fluoroalkyl, fluoroalkoxy or fluoroalkenyl.
  • R 1 is selected from fluoroalkyl, fluoroalkoxy or fluoroalkenyl
  • R 2 is a single bond
  • R 3 is selected from R 4 is selected from a hydrocarbon group, an ether group or a polyether chain
  • R 5 is a single bond
  • R 6 is selected from a fluoroalkyl group, a fluoroalkoxy group or a fluoroalkenyl group.
  • the compound shown in the structural formula 1 is selected from one or more of the following compounds:
  • the mass percentage of the compound represented by the structural formula 1 is 10% to 90%.
  • the solvent further includes a co-solvent, and the volume ratio of the co-solvent to the compound represented by the structural formula 1 is 1:100-90:10;
  • the co-solvent includes one or more of ether-based solvents, nitrile-based solvents, carbonate-based solvents and carboxylate-based solvents.
  • the present invention provides a battery comprising a positive electrode, a negative electrode and the above-mentioned non-aqueous electrolyte.
  • the solvent includes the compound shown in Structural Formula 1.
  • Structural Formula 1 the compound shown in Structural Formula 1.
  • the compound represented by structural formula 1 can preferably be decomposed with other components in the electrolyte on the electrode surface, participate in the formation of a passivation film on the electrode surface, and form a metal fluoride-rich SEI/CEI film on the electrode surface, effectively inhibiting lithium dendrites. growth and improve the cycle stability of the battery.
  • the compound represented by the structural formula 1 has high oxidation resistance potential and flame retardancy, which can reduce the flammability of the obtained electrolyte and improve its safety. When applied to a lithium-sulfur battery, the compound represented by the structural formula 1 can also reduce the solubility of lithium polysulfide in the electrolyte, and slow down the shuttle effect of lithium polysulfide.
  • FIG. 1 is a graph showing the capacity retention rate of the lithium-sulfur half-battery provided in Example 2 of the present invention under the condition of 0.2C for 100 cycles.
  • Example 2 is a schematic diagram showing the results of cycling the lithium-copper half-cell provided in Example 4 of the present invention for 400 cycles under the conditions of a current density of 1 mA/cm 2 and a surface capacity of 1 mAh/cm 2 .
  • FIG. 3 is a schematic diagram showing the results of cycling the lithium-copper half-cell provided in Comparative Example 1 of the present invention for 100 cycles under the conditions of a current density of 1 mA/cm 2 and a surface capacity of 1 mAh/cm 2 .
  • An embodiment of the present invention provides a non-aqueous electrolyte solution, including an electrolyte and a solvent, and the solvent includes a compound shown in Structural Formula 1:
  • R 1 is selected from fluoroalkyl, fluoroalkoxy or fluoroalkenyl
  • R 2 is selected from or single bond, n is 1 or 2;
  • R is selected from hydrocarbyl, alkoxy, alkenyl, alkenyloxy, aryl, aryloxy or R 4 is selected from hydrocarbon group, alkoxy group, alkenyl group, alkenyloxy group, aryl group, aryloxy group, ether group or polyether chain, R 5 is selected from or a single bond, m is 1 or 2, and R 6 is selected from fluoroalkyl, fluoroalkoxy or fluoroalkenyl.
  • the compounds represented by the structural formula 1 include fluorine groups exemplified by R 1 and R 6 , which have lower polarity, and also include fluoro groups exemplified by -R 2 -O- or -R 5 -O-.
  • the combination of polar groups, fluorinated groups and polar groups forms a structure similar to surfactants, and its polar groups can have good affinity with conventional solvents such as DME and DMC.
  • the polarity of the substitution group is relatively low, and a stable core-shell structure is formed in the process of mixing with other electrolyte solvents.
  • the outer layer is a fluorinated group compounded by structural formula 1, so that the non-aqueous electrolyte as a whole is in a stable double-sheath solution state, which can effectively reduce the direct contact between the solvent molecules with higher reactivity and the positive and negative electrode interfaces, and then Reduce side reactions unfavorable to electrochemical cycling in batteries to improve battery cycling stability.
  • the compound represented by structural formula 1 can preferably be decomposed with other components in the electrolyte on the electrode surface, participate in the formation of a passivation film on the electrode surface, and form a metal fluoride-rich SEI/CEI film on the electrode surface, effectively suppressing lithium dendrites
  • the shell-core double-sheath structure formed by the compound shown in structural formula 1 will easily react with DME, DMC, etc. It may be locked inside the sheath to avoid the thickness increase of the SEI/CEI film during long-term cycling, thereby avoiding the increase in impedance.
  • the metal fluoride may be lithium fluoride, sodium fluoride, potassium fluoride, etc., depending on the choice of the electrolyte.
  • the compound represented by the structural formula 1 has high oxidation resistance potential and flame retardancy, which can reduce the flammability of the obtained electrolyte and improve its safety. When applied to a lithium-sulfur battery, the compound represented by the structural formula 1 can also reduce the solubility of lithium polysulfide in the electrolyte, and slow down the shuttle effect of lithium polysulfide.
  • the fluoro groups of R 1 and R 6 may be perfluoro or partially fluoro.
  • R 1 and R 6 fluoro groups are related to its polarity. The higher the degree of fluorine substitution, the lower the polarity. The structure depends on the lower polarity of R 1 and R 6.
  • R 1 and R The fluoro group of R 6 is selected from perfluoro groups to ensure that it has relatively low polarity.
  • R 1 and R 6 are each independently selected from wherein, n is selected from 1-4.
  • R 1 has 1 to 10 carbon atoms
  • R 3 when R 3 is selected from hydrocarbon group, alkoxy group, alkenyl group, alkenyloxy group, aryl group or aryloxy group, R 3 has 1 carbon atom number ⁇ 10, the number of carbon atoms of R 4 is 1-10, and the number of carbon atoms of R 6 is 1-10.
  • R 1 has 1 to 5 carbon atoms
  • R 3 is selected from hydrocarbon groups, alkoxy groups, alkenyl groups and alkenyloxy groups with 1 to 3 carbon atoms
  • R 4 has carbon atoms of 1 to 3 1-3, and the number of carbon atoms of R 6 is 1-4.
  • R 1 and R 6 are fluorinated groups, and a relatively long carbon chain is beneficial to improve the oxidation resistance and flame retardancy of the electrolyte.
  • the carbon chain length of R 1 and R 6 is insufficient, which will lead to R 1
  • the oxidation resistance and flame retardancy of the terminal to the electrolyte deteriorate, and the electron and density distribution of the molecule are changed at the same time, which is not conducive to the formation of the shell-core structure and is insufficient to improve the battery performance.
  • the carbon chains of R 1 and R 6 should not be too long, which is not conducive to improving the compatibility of the compound represented by structural formula 1 with other solvents or electrolytes in the electrolyte.
  • the number of carbon atoms of R 1 and R 6 may each be independently selected from 2, 3, 4, 5.
  • the carbon chains of R 3 and R 4 are relatively short, which can reduce steric hindrance, which is beneficial for metal ions to approach O in the compound represented by structural formula 1, and to better complex metal ions.
  • the number of carbon atoms of R 3 and R 4 may each be independently selected from 1, 2, 3, 4.
  • a fluoroalkyl, fluoroalkoxy, fluoroalkenyl, hydrocarbyl, alkoxy, alkenyl, alkenyloxy, aryl, aryloxy, ether, or polyether chain can be Straight chain can also be branched.
  • R 1 is selected from fluoroalkyl, fluoroalkoxy, or fluoroalkenyl
  • R 2 is selected from n is 1 or 2
  • R3 is selected from hydrocarbyl, alkoxy, alkenyl, alkenyloxy, aryl or aryloxy.
  • the compound represented by structural formula 1 When the compound represented by structural formula 1 is selected from structural formula 1-1, its structure mainly includes two parts, one part is a fluorinated non-polar group with R 1 as an example, and the other part is sulfonate and sulfinate
  • the polar groups such as sulfonate and sulfinate have affinity with other solvents or electrolytes when forming a shell-core double-sheath structure with other solvents or electrolytes, and are located in the shell.
  • fluorinated non-polar groups such as R 1 are located outside the shell core double sheath structure, thereby forming a stable dispersion and isolation structure, which is beneficial to reduce the interaction between the electrode and the electrolyte. side effects.
  • R 1 is selected from fluoroalkyl, fluoroalkoxy or fluoroalkenyl;
  • R 2 is a single bond;
  • R 3 is selected from hydrocarbyl, alkoxy, alkenyl, alkenyloxy, aryl group or aryloxy group.
  • the compound represented by Structural Formula 1 is selected from Structural Formula 1-2, its structure mainly includes two parts, one part is a fluorinated non-polar group exemplified by R 1 , and the other part is a polar group exemplified by ethers , when forming a shell-core double-sheath structure with other solvents or electrolytes, polar groups such as ethers have affinity with other solvents or electrolytes and are located inside the shell-core double-sheath structure, R 1 as an example
  • the fluorinated non-polar groups of TiO2 are located outside the shell-core double-sheath structure, thereby forming a stable dispersed and isolated structure, which is beneficial to reduce side reactions between the electrode and the electrolyte.
  • R 1 is selected from fluoroalkyl, fluoroalkoxy, or fluoroalkenyl
  • R 2 is selected from n is 1 or 2
  • R 3 is selected from R 4 is selected from hydrocarbyl, alkoxy, alkenyl, alkenyloxy, aryl or aryloxy
  • R 5 is selected from m is 1 or 2
  • R 6 is selected from fluoroalkyl, fluoroalkoxy or fluoroalkenyl.
  • the compound represented by structural formula 1 When the compound represented by structural formula 1 is selected from structural formulas 1-3, its structure mainly includes three parts, wherein the two end parts are fluorinated non-polar groups exemplified by R 1 and R 6 , and the middle part is bissulfonic acid Polar groups such as esters and bissulfinates, when forming a shell-core double-sheath structure with other solvents or electrolytes, polar groups such as bissulfonates and bissulfinates have the same
  • the affinity of other solvents or electrolytes is located inside the shell-core double-sheath structure, and the fluorinated apolar groups exemplified by R 1 and R 6 are located outside the shell-core double-sheath structure, thereby forming a stable dispersion and
  • the isolated structure is beneficial to reduce the side reaction between the electrode and the electrolyte.
  • the compounds represented by structural formulas 1-3 can be prepared by the following routes:
  • R 1 is selected from fluoroalkyl, fluoroalkoxy or fluoroalkenyl
  • R 2 is a single bond
  • R 3 is selected from R 4 is selected from a hydrocarbon group, an ether group or a polyether chain
  • R 5 is a single bond
  • R 6 is selected from a fluoroalkyl group, a fluoroalkoxy group or a fluoroalkenyl group.
  • R 7 is selected from hydrocarbon groups having 1 to 3 carbon atoms, and r is an integer of 0 to 2.
  • the compound represented by structural formula 1 When the compound represented by structural formula 1 is selected from structural formulas 1-4, its structure mainly includes three parts, wherein the two end parts are fluorinated non-polar groups exemplified by R 1 and R 6 , and the middle part is polyether A polar group such as a chain, when forming a shell-core double-sheath structure with other solvents or electrolytes, a polar group such as a polyether chain has an affinity with other solvents or electrolytes, and is located in the shell-core double-sheath.
  • fluorinated non-polar groups such as R 1 and R 6 are located outside the shell-core double-sheath structure, thereby forming a stable dispersion and isolation structure, which is beneficial to reduce the interaction between the electrode and the electrolyte. side effects.
  • the compounds represented by structural formulas 1-4 can be prepared by the following routes:
  • one of the compounds of structural formula 1-1, structural formula 1-2, structural formula 1-3 and structural formula 1-4 can be selected to be added alone, or two or more of them can be selected to be added in combination.
  • the compound represented by the structural formula 1 is selected from one or more of the following compounds:
  • the mass percentage of the compound represented by the structural formula 1 is 10% to 90%.
  • the mass percentage of the compound represented by the structural formula 1 is 40% to 80%.
  • the mass percentage of the compound represented by the structural formula 1 is 60% to 80%.
  • a shell-core double-sheath structure can be effectively formed in the electrolyte, so as to reduce the occurrence of side reactions of the electrolyte during the battery cycle and improve the electrolysis process. liquid stability.
  • the compound represented by the structural formula 1 is used as the main solvent, and can be mixed with the compound represented by the structural formula 1 through other co-solvents.
  • the solvent further includes a co-solvent, and the volume ratio of the co-solvent to the compound represented by Structural Formula 1 is 1:100-90:10.
  • the volume ratio of the co-solvent to the compound represented by the structural formula 1 is 1:9 to 1:2.
  • the co-solvent includes one or more of ether-based solvents, nitrile-based solvents, carbonate-based solvents and carboxylate-based solvents.
  • the ether solvent includes cyclic ether or chain ether
  • the cyclic ether can be, but not limited to, 1,3-dioxolane (DOL), 1,4-dioxoxane (DX)
  • DOL 1,3-dioxolane
  • DX 1,4-dioxoxane
  • the ether can be specifically, but not limited to, one or more of dimethoxymethane (DMM), 1,2-dimethoxyethane (DME), and diglyme (TEGDME).
  • DDMM dimethoxymethane
  • DME 1,2-dimethoxyethane
  • TEGDME diglyme
  • the nitrile solvent can be specifically, but not limited to, one or more of acetonitrile, glutaronitrile, and malononitrile.
  • Carbonate-based solvents include cyclic carbonates or chain carbonates. Cyclic carbonates can be, but are not limited to, ethylene carbonate (EC), propylene carbonate (PC), ⁇ -butyrolactone (GBL), butylene carbonate One or more of esters (BC); the chain carbonate can be specifically but not limited to dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dipropyl carbonate (DPC) one or more.
  • DMC dimethyl carbonate
  • EMC ethyl methyl carbonate
  • DEC diethyl carbonate
  • DPC dipropyl carbonate
  • the carboxylate solvent can be specifically, but not limited to, methyl acetate (MA), ethyl acetate (EA), propyl acetate (EP), butyl acetate, propyl propionate (PP), and butyl propionate. one or more.
  • the electrolyte includes one or more of lithium, sodium, potassium, magnesium, zinc, and aluminum salts.
  • the electrolyte includes a lithium salt.
  • the electrolyte includes at least one of lithium hexafluorophosphate, lithium bis-trifluoromethanesulfonimide, lithium bis-fluorosulfonimide, lithium tetrafluoroborate, and lithium difluorooxalate borate.
  • the concentration of the electrolyte is 0.1 mol/L-8 mol/L.
  • the concentration of the electrolyte is 0.5mol/L-4mol/L.
  • the concentration of the electrolyte may be 0.5 mol/L, 1 mol/L, 1.5 mol/L, 2 mol/L, 2.5 mol/L, 3 mol/L, 3.5 mol/L or 4 mol/L.
  • the non-aqueous electrolyte further includes additives including biphenyl, fluorobenzene, vinylene carbonate, trifluoromethyl ethylene carbonate, ethylene ethylene carbonate, 1,3-propane Sultone, 1,4-butanesultone, vinyl sulfate, vinyl sulfite, methylene methanedisulfonate, succinonitrile, adiponitrile, 1,2-bis(2-cyanoethyl) oxy)ethane and one or more of 1,3,6-hexanetrinitrile.
  • additives including biphenyl, fluorobenzene, vinylene carbonate, trifluoromethyl ethylene carbonate, ethylene ethylene carbonate, 1,3-propane Sultone, 1,4-butanesultone, vinyl sulfate, vinyl sulfite, methylene methanedisulfonate, succinonitrile, adiponitrile, 1,2-bis(2-cyanoethy
  • the additive is added in an amount of 0.01-5.0% based on 100% of the total mass of the non-aqueous electrolyte.
  • the additive amount can be 0.1%, 0.2%, 0.5%, 0.8%, 1%, 1.5%, 1.8%, 2%, 2.1%, 2.4%, 3%, 3.5%, 4%, 4.5% or 5%.
  • Another embodiment of the present invention provides a battery including a positive electrode, a negative electrode, and the above-mentioned non-aqueous electrolyte.
  • the battery since the battery includes the above-mentioned non-aqueous electrolyte, it has more excellent high voltage stability and safety; by inhibiting the growth of metal dendrites to slow down the decay of battery capacity, when applied to lithium-sulfur batteries, it can also reduce polysulfides.
  • the solubility of lithium in the electrolyte avoids the shuttle effect that causes irreversible loss of active material and capacity due to its dissolving in the electrolyte and diffusing into the anode, which significantly improves the cycle stability of the resulting battery.
  • the battery is a secondary battery
  • the secondary battery may be a lithium secondary battery, a potassium secondary battery, a sodium secondary battery, a magnesium secondary battery, a zinc secondary battery, or an aluminum secondary battery Wait.
  • the battery is a lithium metal battery, a lithium ion battery or a lithium sulfur battery.
  • the positive electrode includes a positive electrode active material capable of reversibly intercalating/deintercalating metal ions (lithium ions, sodium ions, potassium ions, magnesium ions, zinc ions, aluminum ions, etc.), preferably, the positive electrode
  • the active material is selected from at least one of NCM111, NCM622, NCM532, NCM811, LiFePO 4 , LiCO 2 , LiMnO 2 , LiNiMnO 2 , sulfur and composites thereof.
  • the negative electrode includes a negative electrode active material
  • the negative electrode active material includes carbon-based negative electrodes, silicon-based negative electrodes, tin-based negative electrodes, lithium negative electrodes, sodium negative electrodes, potassium negative electrodes, magnesium negative electrodes, zinc negative electrodes, and aluminum negative electrodes.
  • the carbon-based negative electrode can include graphite, hard carbon, soft carbon, graphene, mesocarbon microspheres, etc.
  • the silicon-based negative electrode can include silicon, silicon carbon, silicon oxide, silicon metal compounds, etc.
  • the tin-based negative electrode can include tin, tin, etc. Carbon, tin oxygen, tin metal compounds
  • the lithium negative electrode may include metallic lithium or lithium alloys.
  • the lithium alloy may be at least one of a lithium-silicon alloy, a lithium-sodium alloy, a lithium-potassium alloy, a lithium-aluminum alloy, a lithium-tin alloy, and a lithium-indium alloy.
  • the negative electrode active material is selected from at least one of metallic lithium and its alloys, graphite, and mesocarbon microspheres.
  • the battery further includes a separator located between the positive electrode and the negative electrode.
  • the separator can be an existing conventional separator, and can be a polymer separator, non-woven fabric, etc., including but not limited to single-layer PP (polypropylene), single-layer PE (polyethylene), double-layer PP/PE, double-layer PP /PP and three-layer PP/PE/PP and other separators.
  • This embodiment is used to illustrate the non-aqueous electrolyte, battery and preparation method thereof disclosed in the present invention, and includes the following operation steps:
  • a mixed solvent of fluoroethylene carbonate (FEC) and compound 1 in a volume ratio of 2:8 was prepared, LiFSI was dissolved in the obtained mixed solvent to make the lithium salt concentration 1M, and 0.5% by mass of DTD was added to obtain Electrolyte.
  • the electrolyte was assembled into a lithium-copper half - cell, and the lithium sheet was used as the negative electrode and the copper foil as the positive electrode, and electrochemical tests were carried out.
  • the average Coulombic efficiency of 100 cycles under the condition is 98.5%.
  • This embodiment is used to illustrate the non-aqueous electrolyte, battery and preparation method thereof disclosed in the present invention, and includes the following operation steps:
  • This embodiment is used to illustrate the non-aqueous electrolyte, battery and preparation method thereof disclosed in the present invention, and includes the following operation steps:
  • This embodiment is used to illustrate the non-aqueous electrolyte, battery and preparation method thereof disclosed in the present invention, including most of the operation steps in Embodiment 1, and the differences are:
  • Ethylene glycol dimethyl ether (DME) and compound 7 were mixed in a volume ratio of 2:8 as a mixed solvent.
  • the obtained lithium-copper half-cell was electrochemically tested, and the test results are shown in Figure 2.
  • the test results show that, under the conditions of 1mA/ cm2 current density and 1mAh/ cm2 surface capacity, the average coulombic efficiency of the battery is 99.24%.
  • This embodiment is used to illustrate the non-aqueous electrolyte, battery and preparation method thereof disclosed in the present invention, including most of the operation steps in Embodiment 1, and the differences are:
  • a mixed solvent of fluoroethylene carbonate (FEC) and compound 1 in a volume ratio of 1:10 was prepared.
  • the obtained lithium-copper half-cell is electrochemically tested.
  • the test results show that the lithium-copper half-cell has an average coulombic efficiency of 96.9% for 100 cycles under the conditions of a current density of 1 mA/cm 2 and a surface capacity of 1 mAh/cm 2 .
  • This embodiment is used to illustrate the non-aqueous electrolyte, battery and preparation method thereof disclosed in the present invention, including most of the operation steps in Embodiment 1, and the differences are:
  • a mixed solvent of fluoroethylene carbonate (FEC) and compound 1 in a volume ratio of 1:20 was prepared.
  • the obtained lithium-copper half-cell was electrochemically tested, and the test results showed that the average coulombic efficiency of the lithium-copper half-cell cycled for 100 cycles under the conditions of a current density of 1 mA/cm 2 and a surface capacity of 1 mAh/cm 2 was 95.0%.
  • This embodiment is used to illustrate the non-aqueous electrolyte, battery and preparation method thereof disclosed in the present invention, including most of the operation steps in Embodiment 1, and the differences are:
  • a mixed solvent of fluoroethylene carbonate (FEC) and compound 9 in a volume ratio of 2:8 was prepared, and 1M LiFSI was dissolved.
  • the obtained electrolyte lithium-copper half-cell is electrochemically tested.
  • the test results show that the lithium-copper half-cell has an average Coulomb efficiency of 99.1% for 100 cycles under the conditions of a current density of 1 mA/cm 2 and a surface capacity of 1 mAh/cm 2 .
  • This embodiment is used to illustrate the non-aqueous electrolyte, battery and preparation method thereof disclosed in the present invention, including most of the operation steps in Embodiment 1, and the differences are:
  • a mixed solvent of fluoroethylene carbonate (FEC) and compound 10 in a volume ratio of 2:8 was prepared, and 1M LiFSI was dissolved to prepare an electrolyte.
  • the obtained electrolyte lithium-copper half-cell is electrochemically tested.
  • the test results show that the lithium-copper half-cell has an average Coulomb efficiency of 99.2% for 100 cycles under the conditions of a current density of 1 mA/cm 2 and a surface capacity of 1 mAh/cm 2 .
  • This embodiment is used to illustrate the non-aqueous electrolyte, battery and preparation method thereof disclosed in the present invention, including most of the operation steps in Embodiment 1, and the differences are:
  • a mixed solvent of ethylene glycol dimethyl ether (DME) and compound 11 in a volume ratio of 1:9 was prepared, and 1M LiFSI was dissolved to obtain an electrolyte.
  • the obtained electrolyte was subjected to electrochemical test of lithium-copper half-cell.
  • the test results showed that the lithium-copper half-cell had an average Coulomb efficiency of 98.9% for 100 cycles under the conditions of a current density of 1mA/ cm2 and a surface capacity of 1mAh/ cm2 .
  • This embodiment is used to illustrate the non-aqueous electrolyte, battery and preparation method thereof disclosed in the present invention, including most of the operation steps in Embodiment 1, and the differences are:
  • a mixed solvent of ethylene glycol dimethyl ether (DME) and compound 12 in a volume ratio of 2:8 was prepared, and 2M LiFSI was dissolved to obtain an electrolyte.
  • the obtained electrolyte was subjected to electrochemical tests of lithium-copper half-cells.
  • the test results showed that the average coulombic efficiency of the lithium-copper half-cell for 100 cycles under the conditions of 1mA/cm 2 current density and 1mAh/cm 2 surface capacity was 99.2%.
  • This embodiment is used to illustrate the non-aqueous electrolyte, battery and preparation method thereof disclosed in the present invention, including most of the operation steps in Embodiment 1, and the differences are:
  • a mixed solvent of ethylene glycol dimethyl ether (DME) and compound 12 in a volume ratio of 2:8 was prepared, and 2M LiFSI was dissolved to obtain an electrolyte.
  • the obtained electrolyte was subjected to electrochemical test of lithium-copper half-cell.
  • the test results showed that the average Coulombic efficiency of the lithium-copper half-cell cycled for 100 cycles under the conditions of 1 mA/cm 2 current density and 1 mAh/cm 2 surface capacity was 99.3%.
  • This embodiment is used to illustrate the non-aqueous electrolyte, battery and preparation method thereof disclosed in the present invention, including most of the operation steps in Embodiment 1, and the differences are:
  • a mixed solvent with a volume ratio of dimethyl carbonate (DMC) and compound 14 of 2:8 was prepared, and 2M LiFSI was dissolved to obtain an electrolyte.
  • the obtained electrolyte was subjected to the electrochemical test of the lithium-copper half-cell.
  • the test results showed that the lithium-copper half-cell had an average Coulomb efficiency of 98.3% for 100 cycles under the conditions of a current density of 1 mA/cm 2 and a surface capacity of 1 mAh/cm 2 .
  • This embodiment is used to illustrate the non-aqueous electrolyte, battery and preparation method thereof disclosed in the present invention, including most of the operation steps in Embodiment 1, and the differences are:
  • a mixed solvent with a volume ratio of dimethyl carbonate (DMC) and compound 15 of 2:8 was prepared, and 2M LiFSI was dissolved to obtain an electrolyte.
  • the obtained electrolyte was subjected to electrochemical test of lithium-copper half-cell.
  • the test results showed that the lithium-copper half-cell had an average Coulomb efficiency of 98.0% for 100 cycles under the conditions of a current density of 1 mA/cm 2 and a surface capacity of 1 mAh/cm 2 .
  • a mixed solvent of fluoroethylene carbonate (FEC) and compound 18 in a volume ratio of 2:8 was prepared, and 1M LiFSI was dissolved to obtain an electrolyte.
  • the obtained electrolyte was subjected to electrochemical test of lithium-copper half-cell.
  • the test results showed that the lithium-copper half-cell had an average Coulomb efficiency of 98.9% for 100 cycles under the conditions of a current density of 1mA/ cm2 and a surface capacity of 1mAh/ cm2 .
  • a mixed solvent of fluoroethylene carbonate (FEC) and compound 19 in a volume ratio of 8:2 was prepared, and 1M LiFSI was dissolved to obtain an electrolyte.
  • the obtained lithium-copper half-cell was electrochemically tested, and the test results showed that the average coulombic efficiency of the lithium-copper half-cell cycled for 100 cycles under the conditions of a current density of 1 mA/cm 2 and a surface capacity of 1 mAh/cm 2 was 99.1%.
  • This comparative example is used to compare and illustrate the non-aqueous electrolyte, battery and preparation method thereof disclosed in the present invention, including most of the operation steps in Example 1, and the difference is:
  • Fluoroethylene carbonate was used as the solvent of the electrolyte.
  • the obtained lithium-copper half-cell was electrochemically tested, and the test results showed that the average Coulombic efficiency of the lithium-copper half-cell cycled for 100 cycles under the conditions of a current density of 1 mA/cm 2 and a surface capacity of 1 mAh/cm 2 was 80%.
  • Fluorinated ethylene carbonate (FEC) and compound 20 were mixed in a volume ratio of 2:8 as a mixed solvent.
  • the obtained lithium-copper half-cell was electrochemically tested, and the test results are shown in Figure 3.
  • the test results show that the lithium-copper half-cell cycled for 100 cycles under the conditions of a current density of 1mA/ cm2 and a surface capacity of 1mAh/ cm2 with an average coulomb Efficiency is 92%.
  • This comparative example is used to compare and illustrate the non-aqueous electrolyte, battery and preparation method thereof disclosed in the present invention, including most of the operation steps in Example 4, and the difference is:
  • Ethylene glycol dimethyl ether (DME) and compound 21 were mixed in a volume ratio of 2:8 as a mixed solvent.
  • the obtained lithium-copper half-cell was electrochemically tested, and the test results showed that the average coulombic efficiency of the battery was 60% under the conditions of 1 mA/cm 2 current density and 1 mAh/cm 2 surface capacity for 25 cycles.
  • This comparative example is used to compare and illustrate the non-aqueous electrolyte disclosed in the present invention, the battery and the preparation method thereof, including most of the operation steps in Example 2, and the difference is:
  • LiFSI ethylene glycol dimethyl ether
  • DME ethylene glycol dimethyl ether
  • LiFSI LiFSI was dissolved in the solvent to make the lithium salt concentration 2.5M, and 0.5% by mass of DTD was added to obtain an electrolyte solution.
  • the electrolyte was assembled into a lithium-sulfur half-cell, using the lithium sheet as the negative electrode and the sulfur-carbon composite as the positive electrode, and the constant-current charge-discharge electrochemical test was carried out. The test results showed that the lithium-sulfur half-cell cycled for 100 cycles at 0.2C.
  • the rear capacity retention rate was 48.1%.
  • Example 1-1 Comparing the test results of Example 1, Example 5, 6 and Comparative Example 1, it can be seen that in the electrolyte solvent, the compound represented by the structural formula 1-1 can improve the battery performance in a wide range of additions. effect.
  • Solvent FEC cannot complete the multi-cycle charge-discharge cycle of lithium-sulfur battery/lithium metal battery as a single solvent due to its large impedance.
  • Compounds 20 and 21 have low polarity because both sides are substituted by fluorine, which is not conducive to good mutual solubility with conventional solvents such as DME, lithium salts, etc., and further, it is impossible to make the non-aqueous electrolyte as a whole stable double-sheath solution. state, so that the multi-cycle charge-discharge cycle of the lithium-sulfur battery/lithium metal battery cannot be completed.
  • solvent DME When solvent DME is used as a single solvent in lithium-sulfur batteries, the shuttle effect of polysulfides is obvious, and the capacity decay is serious during charge-discharge cycles. Moreover, the solvent molecules are oxidized and decomposed under the condition of high voltage (>4V vs Li+/Li), and the multi-cycle charge-discharge cycle cannot be completed.
  • Example 2 and Comparative Example 4 show that in the electrolyte solvent, the compound represented by the structural formula 1-1 can effectively inhibit the shuttle effect of polysulfides, and significantly improve the cycle capacity retention rate of lithium-sulfur batteries.
  • Example 3 shows that in the electrolyte solvent, the compound represented by the structural formula 1-1 can effectively inhibit the corrosion of the current collector by DME and improve the cycle performance of the lithium metal battery.

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Abstract

为克服现有电解液中溶剂存在稳定性不足，影响电池循环性能的问题，本发明提供了一种非水电解液，包括电解质和溶剂，所述溶剂包括如结构式1所示的化合物： R1-R2-O-R3 结构式1 其中，R1选自氟代烷基、氟代烷氧基或氟代烯基；R2选自 aa或单键，n为1或2；R3选自烃基、烷氧基、烯基、烯氧基、芳基、芳氧基或 bb，R4选自烃基、烷氧基、烯基、烯氧基、芳基、芳氧基、醚基或聚醚链，R5选自 cc或单键，m为1或2，R6选自氟代烷基、氟代烷氧基或氟代烯基。同时，本发明还公开了包括上述非水电解液的电池。本发明提供的非水电解液具有较高的循环稳定性，同时能够抑制锂枝晶的生长和多硫化物的穿梭效应，提高电池的循环性能。

Description

一种非水电解液及电池 技术领域
本发明属于二次电池技术领域，具体涉及一种非水电解液及电池。
背景技术
电解液被誉为锂离子电池中的“血液”，对锂离子电池中电极材料容量的发挥、电池循环稳定性、电池安全性等起着至关重要的作用。
传统的锂离子电池中，由于石墨负极的理论比容量(372mAh/g)较低，使得人们开始寻找具有更高比容量、更低电位的锂金属材料(3860mAh/g，-3.04V vs.SHE)作为负极材料。以碳酸乙烯酯(EC)、碳酸甲乙酯(EMC)、碳酸二甲酯(DMC)、碳酸二乙酯(DEC)等为代表的碳酸酯类电解液溶剂，其并不适用于锂金属电池，这主要是因为锂金属的电位较低，还原性较强，能够与大多数酯类电解液反应，从而在充放电过程中容易导致锂支晶的生长以及死锂的形成，最终使得电池衰减迅速，难以满足需求。此外，由于多硫化锂也可与酯类电解液发生化学反应，因而传统酯类电解液也难以用于锂硫电池。
而以乙二醇二甲醚(DME)、1,3-环戊烷(DOL)为代表的醚类电解液与锂金属反应缓慢，表现出对锂金属较好的稳定性，因而被众多学者用于锂金属电池的研究。此外多硫化锂在醚类电解液中又较好的溶解度，且不与溶剂发生反应，因而醚类电解液也被常用于锂硫电池，经典的配方为1M双三氟甲基磺酰亚胺锂(LiTFSI)溶于DME/DOL(1：1v/v)中，同时添加1～2％LiNO 3作为添加剂。虽然该醚类电解液体系对锂金属有较好的稳定性，可缓解锂枝晶的生长，但是其氧化分解电位较低，难以满足高电压正极材料的需求(如三元正极材料NCM、尖晶石镍锰酸锂等正极材料)。同时，醚类电解液与酯类电解液一样，具有易燃性，给锂离子电池组带来一系列安全隐患。
另一方面，现有一类砜类化合物添加剂，如磺酰胺类化合物或磺酸酯类化合物，虽然通过在电解液中加入砜类化合物能够在较小程度上提高电池的电化学性能，但是现有的砜类化合物添加剂对于电解液的耐氧化性能方面并没有较好的提升作用。
发明内容
针对现有电解液中溶剂存在稳定性不足，影响电池循环性能的问题，本发明提供了一种非水电解液及电池。
本发明解决上述技术问题所采用的技术方案如下：
一方面，本发明提供了一种非水电解液，包括电解质和溶剂，所述溶剂包括如结构式1所示的化合物：
R 1-R 2-O-R 3
结构式1
其中，R 1选自氟代烷基、氟代烷氧基或氟代烯基；
R 2选自
Figure PCTCN2021126977-appb-000001
或单键，n为1或2；
R 3选自烃基、烷氧基、烯基、烯氧基、芳基、芳氧基或
Figure PCTCN2021126977-appb-000002
R 4选自烃基、烷氧基、烯基、烯氧基、芳基、芳氧基、醚基或聚醚链，R 5选自
Figure PCTCN2021126977-appb-000003
或单键，m为1或2，R 6选自氟代烷基、氟代烷氧基或氟代烯基。
可选的，R 1的碳原子数为1～10，R 3选自烃基、烷氧基、烯基、烯氧基、芳基或芳氧基时，R 3的碳原子数为1～10，R 4的碳原子数为1～10，R 6的碳原子数为1～10。
可选的，R 1选自氟代烷基、氟代烷氧基或氟代烯基；R 2选自
Figure PCTCN2021126977-appb-000004
n为1或2；R 3选自烃基、烷氧基、烯基、烯氧基、芳基或芳氧基。
可选的，R 1选自氟代烷基、氟代烷氧基或氟代烯基；R 2为单键；R 3选自烃基、烷氧基、烯基、烯氧基、芳基或芳氧基。
可选的，R 1选自氟代烷基、氟代烷氧基或氟代烯基；R 2选自
Figure PCTCN2021126977-appb-000005
n为1或2；R 3选自
Figure PCTCN2021126977-appb-000006
R 4选自烃基、烷氧基、烯基、烯氧基、芳基或芳氧基，R 5选自
Figure PCTCN2021126977-appb-000007
m为1或2，R 6选自氟代烷基、氟代烷氧基或氟代烯基。
可选的，R 1选自氟代烷基、氟代烷氧基或氟代烯基；R 2为单键；R 3选自
Figure PCTCN2021126977-appb-000008
R 4选自烃基、醚基或聚醚链，R 5为单键，R 6选自氟代烷基、氟代烷氧基或氟代烯基。
可选的，所述结构式1所示的化合物选自如下化合物中的一种或多种：
Figure PCTCN2021126977-appb-000009
Figure PCTCN2021126977-appb-000010
Figure PCTCN2021126977-appb-000011
可选的，以所述电解液的总质量为100％计，所述结构式1所示的化合物的质量百分数为10％～90％。
可选的，所述溶剂还包括有共溶剂，所述共溶剂与所述结构式1所示的化合物的体积比为1:100～90:10；
所述共溶剂包括醚类溶剂、腈类溶剂、碳酸酯类溶剂和羧酸酯类溶剂中的一种或多种。
另一方面，本发明提供了一种电池，包括正极、负极以及如上所述的非水电解液。
根据本发明提供的非水电解液，溶剂中包括了如结构式1所示的化合物，通过在非水电解液中加入上述化合物作为溶剂使用时，能够有效减少反应性较高的溶剂分子与正负极界面的直接接触，以降低电池中对电化学循环不利的副反应。
同时结构式1所示的化合物中能够优选与电解液中其他成分在电极表面分解，参与电极表面钝化膜形成，在电极表面形成富含金属氟化物的SEI/CEI膜，有效抑制锂枝晶的生长，提高电池的循环稳定性。
结构式1所示的化合物具有较高的耐氧化电位和阻燃性，可降低所得电解液的可燃性、提升其安全性。应用于锂硫电池时，结构式1所示的化合物还可降低多硫化锂在电解液中的溶解度，减缓多硫化锂的穿梭效应。
附图说明
图1是本发明实施例2提供的锂硫半电池在0.2C条件下循环100圈的容量保持率示图。
图2是本发明实施例4提供的锂铜半电池在1mA/cm 2电流密度、1mAh/cm 2面容量的条件下循环400圈的结果示意图。
图3是本发明对比例1提供的锂铜半电池在1mA/cm 2电流密度、1mAh/cm 2面容量的条件下循环100圈的结果示意图。
具体实施方式
为了使本发明所解决的技术问题、技术方案及有益效果更加清楚明白，以下结合附图及实施例，对本发明进行进一步详细说明。应当理解，此处所描述的具体实施例仅仅用以解释本发明，并不用于限定本发明。
本发明一实施例提供了一种非水电解液，包括电解质和溶剂，所述溶剂包括如结构式1所示的化合物：
R 1-R 2-O-R 3
结构式1
其中，R 1选自氟代烷基、氟代烷氧基或氟代烯基；
R 2选自
Figure PCTCN2021126977-appb-000012
或单键，n为1或2；
R 3选自烃基、烷氧基、烯基、烯氧基、芳基、芳氧基或
Figure PCTCN2021126977-appb-000013
R 4选自烃基、烷氧基、烯基、烯氧基、芳基、芳氧基、醚基或聚醚链，R 5选自
Figure PCTCN2021126977-appb-000014
或单键，m为1或2，R 6选自氟代烷基、氟代烷氧基或氟代烯基。
结构式1所示的化合物中，包括了以R 1和R 6为例的氟代基团，其极性较低，同时也包括以-R 2-O-或-R 5-O-为例的极性基团，氟代基团和极性基团组合形成的类似于表面活性剂的结构，其极性基团能够与DME、DMC等常规溶剂之间具有较好的亲和性，其氟代基团的极性较低，在与其他电解液溶剂混合的过程中形成稳定的壳核结构，其内核为DME、DMC等常规溶剂、锂盐、以及结构式1所示化合物的极性基团，外层为结构式1所示化合的氟代基团，使非水电解液整体呈稳定的双鞘层溶液状态，能够有效减少反应性较高的溶剂分子与正负极界面的直接接触，进而降低电池中对电化学循环不利的副反应，以提高电池循环稳定性。
同时，结构式1所示的化合物中能够优选与电解液中其他成分在电极表面分解，参与电极表面钝化膜形成，在电极表面形成富含金属氟化物的SEI/CEI膜，有效抑制锂枝晶的生长，同时在SEI/CEI膜形成后，结构式1所示的化合物形成的壳核双鞘层结构将DME、DMC等易于和电极(正负极)表面反应且生成不利于电池循环的溶剂尽可能锁定在鞘层内部，避免SEI/CEI膜在长期循环过程中的厚度增加，进而避免阻抗的提升。其中，金属氟化物根据电解质的选择不同，可以为氟化锂、氟化钠或氟化钾等。
该结构式1所示的化合物具有较高的耐氧化电位和阻燃性，可降低所得电解液的可燃性、提升其安全性。应用于锂硫电池时，结构式1所示的化合物还可降低多硫化锂在电解液中的溶解度，减缓多硫化锂的穿梭效应。
在一些实施例中，在结构式1所示的化合物中，R 1和R 6的氟代基团可以为全氟代或部分氟代。
需要说明的是，R 1和R 6氟代基团的氟取代程度与其极性相关，其氟取代程度越高，其极性越低，同时结构式1所示化合物所形成的壳核双鞘层结构依赖于R 1和R 6的较低的极性，在优选的实施例中，为保证所述结构式1所示化合物在电解液中形成的壳核双鞘层结构的稳定性，R 1和R 6的氟代基团选自全氟代基团，以保证其具有相对较低的极性。
在优选的实施例中，R 1和R 6各自独立地选自
Figure PCTCN2021126977-appb-000015
其中，n选自1～4。
在一些实施例中，R 1的碳原子数为1～10，R 3选自烃基、烷氧基、烯基、烯氧基、芳基或芳氧基时，R 3的碳原子数为1～10，R 4的碳原子数为1～10，R 6的碳原子数为1～10。
在优选的实施例中，R 1的碳原子数为1～5，R 3选自碳原子数为1～3的烃基、烷氧基、烯基、烯氧基，R 4的碳原子数为1～3，R 6的碳原子数为1～4。
具体的，R 1和R 6为氟代基团，碳链相对较长一些有利于提高电解液的耐氧化性能和阻燃性，R 1和R 6的碳链长度不足，则会导致R 1端对于电解液的耐氧化性能和阻燃性劣化，同时改变分子的电子与密度分布，不利于壳核结构的形成，对电池性能提升不足。同时，R 1和R 6的碳链也不能过长，过长的碳链不利于结构式1所示的化合物与电解液中其他溶剂或电解质的相容性的提高。
在一些实施例中，R 1和R 6的碳原子数可各自独立地选自2、3、4、5。
R 3和R 4的碳链相对短一些，可减少位阻，有利于金属离子接近结构式1所示化合物中的O，更好地络合金属离子。
在一些实施例中，R 3和R 4的碳原子数可各自独立地选自1、2、3、4。
在一些实施例中，氟代烷基、氟代烷氧基、氟代烯基、烃基、烷氧基、烯基、烯氧基、芳基、芳氧基、醚基或聚醚链可以是直链的也可以是支链的。
在一些实施例中，R 1选自氟代烷基、氟代烷氧基或氟代烯基；R 2选自
Figure PCTCN2021126977-appb-000016
n为1或2；R 3选自烃基、烷氧基、烯基、烯氧基、芳基或芳氧基。
在本实施例中，结构式1所示化合物的示例结构为：
Figure PCTCN2021126977-appb-000017
当结构式1所示化合物选自结构式1-1时，其结构主要包括两个部分，一部分为以R 1为例的氟代非极性基团，另一部分为磺酸酯、亚磺酸酯为例的极性基团，在与其他溶剂或电解质形成壳核双鞘层结构时，磺酸酯、亚磺酸酯为例的极性基团具有与其他溶剂或电解质的亲和性，位于壳核双鞘层结构的内部，R 1为例的氟代非极性基团位于壳核双鞘层结构的外部，进而形成稳定的分散和隔离的结构，有利于降低电极与电解液之间的副反应。
在一些实施例中，R 1选自氟代烷基、氟代烷氧基或氟代烯基；R 2为单键；R 3选自烃基、烷氧基、烯基、烯氧基、芳基或芳氧基。
在本实施例中，结构式1所示化合物的示例结构为：
R 1-O-R 3
结构式1-2。
当结构式1所示化合物选自结构式1-2时，其结构主要包括两个部分，一部分为以R 1为例的氟代非极性基团，另一部分为醚类为例的极性基团，在与其他溶剂或电解质形成壳核双鞘层结构时，醚类为例的极性基团具有与其他溶剂或电解质的亲和性，位于壳核双鞘层结构的内部，R 1为例的氟代非极性基团位于壳核双鞘层结构的外部，进而形成稳定的分散和隔离 的结构，有利于降低电极与电解液之间的副反应。
在一些实施例中，R 1选自氟代烷基、氟代烷氧基或氟代烯基；R 2选自
Figure PCTCN2021126977-appb-000018
n为1或2；R 3选自
Figure PCTCN2021126977-appb-000019
R 4选自烃基、烷氧基、烯基、烯氧基、芳基或芳氧基，R 5选自
Figure PCTCN2021126977-appb-000020
m为1或2，R 6选自氟代烷基、氟代烷氧基或氟代烯基。
在本实施例中，结构式1所示化合物的示例结构为：
Figure PCTCN2021126977-appb-000021
当结构式1所示化合物选自结构式1-3时，其结构主要包括三个部分，其中两个端部为以R 1和R 6为例的氟代非极性基团，中间部分为双磺酸酯、双亚磺酸酯为例的极性基团，在与其他溶剂或电解质形成壳核双鞘层结构时，双磺酸酯、双亚磺酸酯为例的极性基团具有与其他溶剂或电解质的亲和性，位于壳核双鞘层结构的内部，R 1和R 6为例的氟代非极性基团位于壳核双鞘层结构的外部，进而形成稳定的分散和隔离的结构，有利于降低电极与电解液之间的副反应。
结构式1-3所示的化合物可通过以下路线制备得到：
Figure PCTCN2021126977-appb-000022
在一些实施例中，R 1选自氟代烷基、氟代烷氧基或氟代烯基；R 2为单键；R 3选自
Figure PCTCN2021126977-appb-000023
R 4选自烃基、醚基或聚醚链，R 5为单键，R 6选自氟代烷基、氟代烷氧基或氟代烯基。
在本实施例中，结构式1所示化合物的示例结构为：
Figure PCTCN2021126977-appb-000024
其中，R 7选自碳原子数1～3的烃基，r为0～2的整数。
当结构式1所示化合物选自结构式1-4时，其结构主要包括三个部分，其中两个端部为以R 1和R 6为例的氟代非极性基团，中间部分为聚醚链为例的极性基团，在与其他溶剂或电 解质形成壳核双鞘层结构时，聚醚链为例的极性基团具有与其他溶剂或电解质的亲和性，位于壳核双鞘层结构的内部，R 1和R 6为例的氟代非极性基团位于壳核双鞘层结构的外部，进而形成稳定的分散和隔离的结构，有利于降低电极与电解液之间的副反应。
结构式1-4所示的化合物可通过以下路线制备得到：
Figure PCTCN2021126977-appb-000025
在不同的实施例中，结构式1-1、结构式1-2、结构式1-3和结构式1-4的化合物可选择其中一种单独添加，也可选择其中两种以上组合添加。
在一些实施例中，所述结构式1所示的化合物选自如下化合物中的一种或多种：
Figure PCTCN2021126977-appb-000026
Figure PCTCN2021126977-appb-000027
需要说明的是，以上是本发明所要求保护的部分化合物，但不限于此，不应理解为对本发明的限制。
在一些实施例中，以所述电解液的总质量为100％计，所述结构式1所示的化合物的质量百分数为10％～90％。
在优选的实施例中，以所述电解液的总质量为100％计，所述结构式1所示的化合物的质量百分数为40％～80％。
在更优选的实施例中，以所述电解液的总质量为100％计，所述结构式1所示的化合物的质量百分数为60％～80％。
所述电解液中，结构式1所示的化合物添加量处于上述范围内时，能够有效在电解液中形成壳核双鞘层结构，以减少电解液在电池循环过程中副反应的发生，提高电解液的稳定性。
需要说明的是，在本实施例中，所述结构式1所示的化合物是作为溶剂主体使用，可通过其他共溶剂与结构式1所示的化合物混合使用。
在一些实施例中，所述溶剂还包括有共溶剂，所述共溶剂与所述结构式1所示的化合物的体积比为1:100～90:10。
在更优选的实施例中，所述共溶剂与所述结构式1所示的化合物的体积比为1:9～1:2。
所述共溶剂包括醚类溶剂、腈类溶剂、碳酸酯类溶剂和羧酸酯类溶剂中的一种或多种。
在一些实施例中，醚类溶剂包括环状醚或链状醚，环状醚具体可以但不限于是1,3-二氧戊烷(DOL)、1,4-二氧惡烷(DX)、冠醚、四氢呋喃(THF)、2-甲基四氢呋喃(2-CH 3-THF)，2-三氟甲基四氢呋喃(2-CF 3-THF)中的一种或多种；所述链状醚具体可以但不限于是二甲氧 基甲烷(DMM)、1,2-二甲氧基乙烷(DME)、二甘醇二甲醚(TEGDME)中的一种或多种。腈类溶剂具体可以但不限于是乙腈、戊二腈、丙二腈中的一种或多种。碳酸酯类溶剂包括环状碳酸酯或链状碳酸酯，环状碳酸酯具体可以但不限于是碳酸乙烯酯(EC)、碳酸丙烯酯(PC)、γ-丁内酯(GBL)、碳酸亚丁酯(BC)中的一种或多种；链状碳酸酯具体可以但不限于是碳酸二甲酯(DMC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)、碳酸二丙酯(DPC)中的一种或多种。羧酸酯类溶剂具体可以但不限于是乙酸甲酯(MA)、乙酸乙酯(EA)、乙酸丙酯(EP)、乙酸丁酯、丙酸丙酯(PP)、丙酸丁酯中的一种或多种。
在一些实施例中，所述电解质包括锂盐、钠盐、钾盐、镁盐、锌盐和铝盐中的一种或多种。
在优选的实施例中，所述电解质包括锂盐。
在更优选的实施例中，所述电解质包括六氟磷酸锂、双三氟甲基磺酰亚胺锂、双氟磺酰亚胺锂、四氟硼酸锂、二氟草酸硼酸锂中的至少一种。
在一些实施例中，所述非水电解液中，所述电解质的浓度为0.1mol/L-8mol/L。
在优选的实施例中，所述非水电解液中，所述电解质的浓度为0.5mol/L-4mol/L。
具体的，所述电解质的浓度可以为0.5mol/L、1mol/L、1.5mol/L、2mol/L、2.5mol/L、3mol/L、3.5mol/L或4mol/L。
在一些实施例中，所述非水电解液还包括添加剂，所述添加剂包括联苯、氟苯、碳酸亚乙烯酯、三氟甲基碳酸乙烯酯、碳酸乙烯亚乙酯、1,3-丙磺酸内酯、1,4-丁磺酸内酯、硫酸乙烯酯、亚硫酸乙烯酯、甲烷二磺酸亚甲酯、丁二腈、己二腈、1,2-二(2-氰乙氧基)乙烷和1,3,6-己烷三腈中的一种或多种。
在一些实施例中，以所述非水电解液的总质量为100％计，所述添加剂的添加量为0.01～5.0％。
具体的，所述添加剂的添加量可以为0.1％、0.2％、0.5％、0.8％、1％、1.5％、1.8％、2％、2.1％、2.4％、3％、3.5％、4％、4.5％或5％。
本发明的另一实施例提供了一种电池，包括正极、负极以及如上所述的非水电解液。
所述电池由于包括上述非水电解液，因此具有更优异的高电压稳定性和安全性；通过抑制金属枝晶的生长以减缓电池容量的衰减，应用于锂硫电池时，还能够降低多硫化锂在电解液中的溶解度，避免其溶于电解液并向负极扩散导致活性物质和容量不可逆损失的穿梭效应，使所得电池的循环稳定性得到显著提升。
在一些实施例中，所述电池为二次电池，所述二次电池可以是锂二次电池、钾二次电池、钠二次电池、镁二次电池、锌二次电池、铝二次电池等。
在优选的实施例中，所述电池为锂金属电池、锂离子电池或锂硫电池。
在一些实施例中，所述正极包括能够可逆地嵌入/脱嵌金属离子(锂离子、钠离子、钾离子、镁离子、锌离子、铝离子等)的正极活性材料，优选的，所述正极活性材料选自NCM111、NCM622、NCM532、NCM811、LiFePO 4、LiCO 2、LiMnO 2、LiNiMnO 2、硫及其复合物中的至少一种。
在一些实施例中，所述负极包括负极活性材料，所述负极活性材料包括碳基负极、硅基负极、锡基负极、锂负极、钠负极、钾负极、镁负极、锌负极和铝负极中的一种或多种。其中碳基负极可包括石墨、硬碳、软碳、石墨烯、中间相碳微球等；硅基负极可包括硅、硅碳、硅氧、硅金属化合物等；锡基负极可包括锡、锡碳、锡氧、锡金属化合物；锂负极可包括金属锂或锂合金。锂合金具体可以是锂硅合金、锂钠合金、锂钾合金、锂铝合金、锂锡合金和锂铟合金中的至少一种。
在优选的实施例中，所述负极活性材料选自金属锂及其合金、石墨、中间相碳微球中的至少一种。
在一些实施例中，所述电池中还包括有隔膜，所述隔膜位于所述正极和所述负极之间。
所述隔膜可为现有常规隔膜，可以是聚合物隔膜、无纺布等，包括但不限于单层PP(聚丙烯)、单层PE(聚乙烯)、双层PP/PE、双层PP/PP和三层PP/PE/PP等隔膜。
以下通过实施例对本发明进行进一步的说明。
实施例1
本实施例用于说明本发明公开的非水电解液、电池及其制备方法，包括以下操作步骤：
Figure PCTCN2021126977-appb-000028
配制氟代碳酸乙烯酯(FEC)和化合物1体积比为2:8的混合溶剂，将LiFSI溶于所得到的该混合溶剂中使锂盐浓度为1M，并添加0.5％质量份的DTD，得到电解液。将该电解液组装锂铜半电池，采用锂片为负极，铜箔为正极，进行电化学测试，测试结果表明，该锂铜半电池在1mA/cm 2电流密度、1mAh/cm 2面容量的条件下循环100圈平均库伦效率为98.5％。
实施例2
本实施例用于说明本发明公开的非水电解液、电池及其制备方法，包括以下操作步骤：
Figure PCTCN2021126977-appb-000029
配制乙二醇二甲醚(DME)和化合物2体积比为3:7的混合溶剂，将LiFSI溶于所得到的该混合溶剂中使锂盐浓度为2.5M，并添加0.5％质量份的DTD，得到电解液。将该电解液组装锂硫半电池，采用锂片为负极，硫碳复合物为正极，进行恒流充放电电化学测试，测试 结果如图1所示，由图1可知，该锂硫半电池在0.2C条件下循环100圈循环后容量保持率为85.6％。
实施例3
本实施例用于说明本发明公开的非水电解液、电池及其制备方法，包括以下操作步骤：
Figure PCTCN2021126977-appb-000030
配制乙二醇二甲醚(DME)和化合物3体积比为3:7的混合溶剂，将LiFSI溶于所得到的该混合溶剂中使锂盐浓度为2.0M，并添加0.5％质量份的DTD，得到电解液。将该电解液组装锂金属电池，利用NCM622为正极，锂片为负极，进行电化学测试，测试结果表明，该锂金属电池在0.5C电流密度的条件下循环100圈容量保持率为87％。
实施例4
本实施例用于说明本发明公开的非水电解液、电池及其制备方法，包括实施例1中大部分操作步骤，其不同之处在于：
Figure PCTCN2021126977-appb-000031
采用乙二醇二甲醚(DME)和化合物7以体积比为2:8混合作为混合溶剂。
得到的锂铜半电池进行电化学测试，测试结果如图2所示，测试结果显示，在1mA/cm 2电流密度、1mAh/cm 2面容量的条件下循环400圈，电池的平均库伦效率为99.24％。
实施例5
本实施例用于说明本发明公开的非水电解液、电池及其制备方法，包括实施例1中大部分操作步骤，其不同之处在于：
Figure PCTCN2021126977-appb-000032
配制氟代碳酸乙烯酯(FEC)和化合物1体积比为1:10的混合溶剂。
得到的锂铜半电池进行电化学测试，测试结果表明，该锂铜半电池在1mA/cm 2电流密度、1mAh/cm 2面容量的条件下循环100圈平均库伦效率为96.9％。
实施例6
本实施例用于说明本发明公开的非水电解液、电池及其制备方法，包括实施例1中大部分操作步骤，其不同之处在于：
Figure PCTCN2021126977-appb-000033
配制氟代碳酸乙烯酯(FEC)和化合物1体积比为1:20的混合溶剂。
得到的锂铜半电池进行电化学测试，测试结果表明，该锂铜半电池在1mA/cm 2电流密度、1mAh/cm 2面容量的条件下循环100圈平均库伦效率为95.0％。
实施例7
本实施例用于说明本发明公开的非水电解液、电池及其制备方法，包括实施例1中大部分操作步骤，其不同之处在于：
Figure PCTCN2021126977-appb-000034
配制氟代碳酸乙烯酯(FEC)和化合物9体积比为2:8的混合溶剂，溶解1M LiFSI。
得到的电解液锂铜半电池进行电化学测试，测试结果表明，该锂铜半电池在1mA/cm 2电流密度、1mAh/cm 2面容量的条件下循环100圈平均库伦效率为99.1％。
实施例8
本实施例用于说明本发明公开的非水电解液、电池及其制备方法，包括实施例1中大部分操作步骤，其不同之处在于：
Figure PCTCN2021126977-appb-000035
配制氟代碳酸乙烯酯(FEC)和化合物10体积比为2:8的混合溶剂，溶解1M LiFSI配制电解液。
得到的电解液锂铜半电池进行电化学测试，测试结果表明，该锂铜半电池在1mA/cm 2电流密度、1mAh/cm 2面容量的条件下循环100圈平均库伦效率为99.2％。
实施例9
本实施例用于说明本发明公开的非水电解液、电池及其制备方法，包括实施例1中大部分操作步骤，其不同之处在于：
Figure PCTCN2021126977-appb-000036
配制乙二醇二甲醚(DME)和化合物11体积比为1:9的混合溶剂，溶解1M LiFSI得到电解液。
将得到的电解液进行锂铜半电池电化学测试，测试结果表明，该锂铜半电池在1mA/cm 2电流密度、1mAh/cm 2面容量的条件下循环100圈平均库伦效率为98.9％。
实施例10
本实施例用于说明本发明公开的非水电解液、电池及其制备方法，包括实施例1中大部分操作步骤，其不同之处在于：
Figure PCTCN2021126977-appb-000037
配制乙二醇二甲醚(DME)和化合物12体积比为2:8的混合溶剂，溶解2M LiFSI得到电解液。
将得到的电解液进行锂铜半电池电化学测试，测试结果表明，该锂铜半电池在1mA/cm 2电流密度、1mAh/cm 2面容量的条件下循环100圈平均库伦效率为99.2％。
实施例11
本实施例用于说明本发明公开的非水电解液、电池及其制备方法，包括实施例1中大部分操作步骤，其不同之处在于：
Figure PCTCN2021126977-appb-000038
配制乙二醇二甲醚(DME)和化合物12体积比为2:8的混合溶剂，溶解2M LiFSI得到电解液。
将得到的电解液进行锂铜半电池电化学测试，测试结果表明，该锂铜半电池在1mA/cm 2 电流密度、1mAh/cm 2面容量的条件下循环100圈平均库伦效率为99.3％。
实施例12
本实施例用于说明本发明公开的非水电解液、电池及其制备方法，包括实施例1中大部分操作步骤，其不同之处在于：
Figure PCTCN2021126977-appb-000039
配制碳酸二甲酯(DMC)和化合物14体积比为2:8的混合溶剂，溶解2M LiFSI得到电解液。
将得到的电解液进行锂铜半电池电化学测试，测试结果表明，该锂铜半电池在1mA/cm 2电流密度、1mAh/cm 2面容量的条件下循环100圈平均库伦效率为98.3％。
实施例13
本实施例用于说明本发明公开的非水电解液、电池及其制备方法，包括实施例1中大部分操作步骤，其不同之处在于：
Figure PCTCN2021126977-appb-000040
配制碳酸二甲酯(DMC)和化合物15体积比为2:8的混合溶剂，溶解2M LiFSI得到电解液。
将得到的电解液进行锂铜半电池电化学测试，测试结果表明，该锂铜半电池在1mA/cm 2电流密度、1mAh/cm 2面容量的条件下循环100圈平均库伦效率为98.0％。
实施例14
Figure PCTCN2021126977-appb-000041
配制氟代碳酸乙烯酯(FEC)和化合物18体积比为2:8的混合溶剂，溶解1M LiFSI得到电解液。
将得到的电解液进行锂铜半电池电化学测试，测试结果表明，该锂铜半电池在1mA/cm 2电流密度、1mAh/cm 2面容量的条件下循环100圈平均库伦效率为98.9％。
实施例15
本实施例用于说明本发明公开的非水电解液、电池及其制备方法，包括实施例7中大部分操作步骤，其不同之处在于：
Figure PCTCN2021126977-appb-000042
配制氟代碳酸乙烯酯(FEC)和化合物19体积比为8:2的混合溶剂，溶解1M LiFSI得到电解液。
得到的锂铜半电池进行电化学测试，测试结果表明，该锂铜半电池在1mA/cm 2电流密度、1mAh/cm 2面容量的条件下循环100圈平均库伦效率为99.1％。
对比例1
本对比例用于对比说明本发明公开的非水电解液、电池及其制备方法，包括实施例1中的大部分操作步骤，其不同之处在于：
采用氟代碳酸乙烯酯(FEC)作为电解液的溶剂。
得到的锂铜半电池进行电化学测试，测试结果显示，该锂铜半电池在1mA/cm 2电流密度、1mAh/cm 2面容量的条件下循环100圈平均库伦效率为80％。
对比例2
Figure PCTCN2021126977-appb-000043
采用氟代碳酸乙烯酯(FEC)和化合物20以体积比为2:8混合作为混合溶剂。
得到的锂铜半电池进行电化学测试，测试结果如图3所示，测试结果显示，该锂铜半电池在1mA/cm 2电流密度、1mAh/cm 2面容量的条件下循环100圈平均库伦效率为92％。
对比例3
本对比例用于对比说明本发明公开的非水电解液、电池及其制备方法，包括实施例4中的大部分操作步骤，其不同之处在于：
Figure PCTCN2021126977-appb-000044
采用乙二醇二甲醚(DME)和化合物21以体积比为2:8混合作为混合溶剂。
得到的锂铜半电池进行电化学测试，测试结果显示，在1mA/cm 2电流密度、1mAh/cm 2面容量的条件下循环25圈，电池的平均库伦效率为60％。
对比例4
本对比例用于对比说明本发明公开的非水电解液、电池及其制备方法，包括实施例2中的大部分操作步骤，其不同之处在于：
采用乙二醇二甲醚(DME)作为电解液溶剂，将LiFSI溶于溶剂中使锂盐浓度为2.5M，并添加0.5％质量份的DTD，得到电解液。将该电解液组装锂硫半电池，采用锂片为负极，硫碳复合物为正极，进行恒流充放电电化学测试，测试结果显示，该锂硫半电池在0.2C条件下循环100圈循环后容量保持率为48.1％。
测试结果说明
对比实施例1～4、实施例7～11和对比例1的测试结果可知，采用本发明提供的结构式1-1或结构式1-2所示的化合物添加入电解液中，对电池性能均有不同程度的提高，说明在加入本发明提供的结构式1-1或结构式1-2所示的化合物的条件下，对于电池性能的提升具有较好的普适性，说明活性锂金属在电化学过程中产生死锂的部分越少，即不容易产生锂枝晶，锂金属负极的可逆性较好，电池稳定性较高。
对比实施例1和对比例2的测试结果可以看出，如对比例2所示，若对于结构式1-1所示的化合物中极性基团部分进行氟代，使得硫氧双键电子云密度降低，降低了磺酸酯分子的极性，难以形成核壳双鞘层结构的电解液，溶剂稳定性差，导致其电池循环性能的劣化。
对比实施例4和对比例3的测试结果可以看出，如对比例3所示，若对于结构式1-2所示的化合物中极性基团部分进行氟代，降低了极性，难以形成核壳双鞘层结构的电解液，溶剂稳定性差，导致其电池循环性能的劣化。
对比实施例1、实施例5、6和对比例1的测试结果可知，在电解液溶剂中，结构式1-1所示的化合物能够在较大的添加范围内对电池性能起到较好的提升作用。
对比实施例12～15的测试结果可知，采用本发明提供的结构式1-3或结构式1-4所示的化合物添加入电解液中，对电池性能均有不同程度的提高。
对比实施例14～15的测试结果可知，在电解液溶剂中，结构式1-4所示的化合物能够在较大的添加范围内对电池性能起到较好的提升作用。
溶剂FEC由于阻抗过大，作为单一溶剂无法完成锂硫电池/锂金属电池的多圈充放电循 环。
化合物20、21由于两边皆为氟取代，其极性较低，不利于与DME等常规溶剂、锂盐等很好地互溶，进一步地，无法使非水电解液整体呈稳定的双鞘层溶液状态，从而无法完成锂硫电池/锂金属电池的多圈充放电循环。
溶剂DME作为单一溶剂应用于锂硫电池时，多硫化物穿梭效应明显，进行充放电循环时容量衰减严重；溶剂DME作为单一溶剂应用于锂金属电池时，由于电解液对正极集流体腐蚀严重，且溶剂分子在高电压(>4V vs Li+/Li)条件下被氧化分解，无法完成多圈充放电循环。
实施例2和对比例4的数据显示，在电解液溶剂中，结构式1-1所示化合物能够有效抑制多硫化物穿梭效应，显著改善锂硫电池的循环容量保持率。
实施例3的数据显示，在电解液溶剂中，结构式1-1所示化合物能够有效抑制DME对集流体的腐蚀，改善锂金属电池的循环性能。
以上所述仅为本发明的较佳实施例而已，并不用以限制本发明，凡在本发明的精神和原则之内所作的任何修改、等同替换和改进等，均应包含在本发明的保护范围之内。

Claims (10)

  1. 一种非水电解液，其特征在于，包括电解质和溶剂，所述溶剂包括如结构式1所示的化合物：
    R 1-R 2-O-R 3
    结构式1
    其中，R 1选自氟代烷基、氟代烷氧基或氟代烯基；
    R 2选自
    Figure PCTCN2021126977-appb-100001
    或单键，n为1或2；
    R 3选自烃基、烷氧基、烯基、烯氧基、芳基、芳氧基或
    Figure PCTCN2021126977-appb-100002
    R 4选自烃基、烷氧基、烯基、烯氧基、芳基、芳氧基、醚基或聚醚链，R 5选自
    Figure PCTCN2021126977-appb-100003
    或单键，m为1或2，R 6选自氟代烷基、氟代烷氧基或氟代烯基。
  2. 根据权利要求1所述的非水电解液，其特征在于，R 1的碳原子数为1～10，R 3选自烃基、烷氧基、烯基、烯氧基、芳基或芳氧基时，R 3的碳原子数为1～10，R 4的碳原子数为1～10，R 6的碳原子数为1～10。
  3. 根据权利要求1所述的非水电解液，其特征在于，R 1选自氟代烷基、氟代烷氧基或氟代烯基；R 2选自
    Figure PCTCN2021126977-appb-100004
    n为1或2；R 3选自烃基、烷氧基、烯基、烯氧基、芳基或芳氧基。
  4. 根据权利要求1所述的非水电解液，其特征在于，R 1选自氟代烷基、氟代烷氧基或氟代烯基；R 2为单键；R 3选自烃基、烷氧基、烯基、烯氧基、芳基或芳氧基。
  5. 根据权利要求1所述的非水电解液，其特征在于，R 1选自氟代烷基、氟代烷氧基或氟代烯基；R 2选自
    Figure PCTCN2021126977-appb-100005
    n为1或2；R 3选自
    Figure PCTCN2021126977-appb-100006
    R 4选自烃基、烷氧基、烯基、烯氧基、芳基或芳氧基，R 5选自
    Figure PCTCN2021126977-appb-100007
    m为1或2，R 6选自氟代烷基、氟代烷氧基或氟代烯基。
  6. 根据权利要求1所述的非水电解液，其特征在于，R 1选自氟代烷基、氟代烷氧基或 氟代烯基；R 2为单键；R 3选自
    Figure PCTCN2021126977-appb-100008
    R 4选自烃基、醚基或聚醚链，R 5为单键，R 6选自氟代烷基、氟代烷氧基或氟代烯基。
  7. 根据权利要求1所述的非水电解液，其特征在于，所述结构式1所示的化合物选自如下化合物中的一种或多种：
    Figure PCTCN2021126977-appb-100009
    Figure PCTCN2021126977-appb-100010
  8. 根据权利要求1所述的非水电解液，其特征在于，以所述电解液的总质量为100％计，所述结构式1所示的化合物的质量百分数为10％～90％。
  9. 根据权利要求1所述的非水电解液，其特征在于，所述溶剂还包括有共溶剂，所述共溶剂与所述结构式1所示的化合物的体积比为1:100～90:10；
    所述共溶剂包括醚类溶剂、腈类溶剂、碳酸酯类溶剂和羧酸酯类溶剂中的一种或多种。
  10. 一种电池，其特征在于，包括正极、负极以及如权利要求1～9任意一项所述的非水电解液。
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