WO2021047500A1 - 电解液、包含该电解液的锂离子电池、电池模块、电池包及装置 - Google Patents

电解液、包含该电解液的锂离子电池、电池模块、电池包及装置 Download PDF

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WO2021047500A1
WO2021047500A1 PCT/CN2020/113973 CN2020113973W WO2021047500A1 WO 2021047500 A1 WO2021047500 A1 WO 2021047500A1 CN 2020113973 W CN2020113973 W CN 2020113973W WO 2021047500 A1 WO2021047500 A1 WO 2021047500A1
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electrolyte
additive
compound
lithium
tris
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PCT/CN2020/113973
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English (en)
French (fr)
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李永坤
吴凯
程博
鞠峰
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宁德时代新能源科技股份有限公司
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Priority to EP20863544.1A priority Critical patent/EP3972030B1/en
Publication of WO2021047500A1 publication Critical patent/WO2021047500A1/zh
Priority to US17/565,474 priority patent/US11942600B2/en

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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
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • 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
    • 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
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0088—Composites
    • H01M2300/0091—Composites in the form of mixtures
    • 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

  • This application relates to the field of batteries, in particular to an electrolyte, a lithium ion battery, a battery module, a battery pack, and a device containing the electrolyte.
  • lithium batteries have the advantages of high specific energy density, wide operating temperature range and long cycle life, making them a mainstream position in the market for a long time.
  • lithium-ion batteries With the widespread application of lithium-ion batteries, higher requirements have been put forward for their environmental adaptability. However, current electronic products sometimes have to be used in environments with high or low temperatures. Compared with conventional environments, lithium-ion batteries Performance will deteriorate significantly when used under extreme conditions.
  • electrolyte As an important part of lithium-ion batteries, electrolyte has a significant impact on the high and low-temperature performance of lithium-ion batteries. However, it is difficult for the electrolyte to simultaneously improve the high-temperature and low-temperature performance of lithium-ion batteries.
  • film-forming additives to passivate the positive electrode can improve the high-temperature performance of lithium-ion batteries
  • conventional additives will deteriorate the impedance of the positive electrode, making the power performance of lithium-ion batteries at low temperatures poor; on the other hand, optimization
  • the electrolyte solvent composition ratio reduces the viscosity of the electrolyte at low temperatures to improve low-temperature performance.
  • this method will deteriorate the high-temperature gas production of lithium-ion batteries and cannot effectively solve the application problems of lithium-ion batteries under extreme conditions.
  • the first aspect of the present application provides an electrolyte, including: an organic solvent, an electrolyte lithium salt dissolved in the organic solvent, and an additive; the additive includes a first additive and a second additive; wherein the first additive One or more selected from the compounds represented by formula I:
  • R 2 and R 3 are each independently selected from saturated or unsaturated hydrocarbylene groups containing 1-10 carbon atoms, the H on the hydrocarbylene group Can be partially substituted or fully substituted by halogen, nitro, cyano, carboxy, sulfonic acid groups;
  • the second additive is selected from one or more of the compounds represented by formula II:
  • R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , and R 12 are each independently selected from alkyl groups or haloalkyl groups containing 1-6 carbon atoms;
  • the compound of formula II is a borate, a phosphite or a phosphate, respectively.
  • the lithium-ion battery can have better high-temperature cycle performance, high-temperature storage performance and lower low-temperature DC resistance, so that the lithium-ion battery has both better high-temperature performance. Performance and low temperature performance.
  • the 1,1-dioxo-tetrahydrothiophene-3,4-yl group, R 2 and R 3 are each independently selected from saturated or unsaturated hydrocarbylene groups containing 1 to 5 carbon atoms.
  • R 2 and R 3 are each independently selected from -CH 2 -, -CH 2 CH 2 -or -CH 2 CH 2 CH 2 -.
  • the first additive is selected from one or more of the following compounds:
  • the first additive can participate in the film formation at the interface between the positive and negative electrodes.
  • the interface film formed on the positive electrode can effectively inhibit the electrolyte from being oxidized and decomposed on the surface of the positive electrode. This can reduce the interface impedance of the positive electrode on the one hand, and optimize the interface resistance of the positive electrode on the other hand. Electrical contact.
  • the second additive is selected from one or more of the following compounds:
  • R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , and R 12 are each independently selected from alkyl groups containing 1-6 carbon atoms or halogenated alkyl groups.
  • R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 are each independently selected from -CH 3 , -CH 2 CH 3 , -CH 2 CH 2 CH 3 or -CH 2 CH 2 CH 2 CH 3 .
  • the second additive is selected from one or more of the following compounds:
  • Compound 2-12 Tris(tri-n-butylsilane) phosphate.
  • the second additive can undergo a complex exchange reaction with the main components in the interface film formed at the negative electrode interface, help to form a more stable interface film at the negative electrode interface, and significantly reduce the impedance of the negative electrode interface, so that the lithium ion battery has a good Power performance.
  • the concentration of the first additive in the electrolyte is 0.1 wt% to 3 wt%. It can prevent the electrolyte from further reacting, avoid the increase of the membrane resistance of the cathode active material layer and the electrolyte interface, and improve the battery performance.
  • the concentration of the second additive in the electrolyte is 0.05 wt% to 2 wt%. It can prevent the first additive from reducing and forming a film on the surface of the negative electrode, improve the cycle performance of the lithium ion battery, facilitate the transmission of lithium ions in the passivation film, and optimize the performance of the lithium ion battery.
  • the electrolyte lithium salt is selected from: LiPF 6 , LiPO 2 F 2 , Li 2 PO 3 F, LiBF 4 , LiSO 3 F, LiTFMSB, LiN(SO 2 F) 2 , LiN(SO 2 One or more of CF 3 ) 2 , LiN(SO 2 C 2 F 5 ) 2 , LiBOB, LiPFO, and lithium tetrafluoro[oxalate-O,O']phosphate; optionally, the electrolyte lithium salt It is selected from: one or more of LiPF 6 , LiBF 4 , LiSO 3 F, LiTFMSB, LiPO 2 F 2 , LiN(SO 2 CF 3 ) 2 , LiN(SO 2 F) 2 , LiBOB and LiPFO.
  • the concentration of the electrolyte lithium salt in the electrolyte is 0.5M-2M; optionally, the concentration of the electrolyte lithium salt in the electrolyte is 0.8M-2M.
  • a second aspect of the present application provides a lithium ion battery.
  • the lithium ion battery includes a positive electrode, a negative electrode, a separator, and the above-mentioned electrolyte of the first aspect of the present application.
  • the third aspect of the present application provides a battery module, the above-mentioned lithium ion battery.
  • the fourth aspect of the present application provides a battery pack, the above-mentioned battery module.
  • a fifth aspect of the present application provides a device including at least one of the above-mentioned lithium ion battery, the above-mentioned battery module, or the above-mentioned battery pack.
  • Fig. 1 is a schematic diagram of an embodiment of a battery.
  • Fig. 2 is an exploded view of Fig. 1.
  • Fig. 3 is a schematic diagram of an embodiment of a battery module.
  • Fig. 4 is a schematic diagram of an embodiment of a battery pack.
  • Fig. 5 is an exploded view of Fig. 4.
  • Fig. 6 is a schematic diagram of an embodiment of the device.
  • any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with other lower limits to form an unspecified range, and any upper limit can be combined with any other upper limit to form an unspecified range.
  • every point or single value between the end points of the range is included in the range. Therefore, each point or single numerical value can be used as its own lower limit or upper limit, combined with any other point or single numerical value, or combined with other lower or upper limits to form an unspecified range.
  • the electrolyte according to the first aspect of the present application includes an organic solvent, an electrolyte lithium salt dissolved in the organic solvent, and additives, wherein the additives include a first additive and a second additive.
  • the first additive is selected from one or more of the compounds described in formula I:
  • R 2 and R 3 are each independently selected from saturated or unsaturated hydrocarbylene groups containing 1-10 carbon atoms, and the H on the hydrocarbylene group may be partially substituted by halogen, nitro, cyano, carboxy, or sulfonic acid groups. Or replace all.
  • R 1 is selected from 1,1-dioxo-tetrahydrothiophene-3,4-yl.
  • R 2 and R 3 are each independently selected from saturated or unsaturated hydrocarbylene groups containing 1 to 5 carbon atoms.
  • R 2 and R 3 are each independently selected from saturated or unsaturated hydrocarbylene groups containing 1 to 5 carbon atoms.
  • R 2 and R 3 are each independently selected from saturated or unsaturated hydrocarbylene groups containing 1 to 5 carbon atoms.
  • R 2 and R 3 are each independently selected from saturated or unsaturated hydrocarbylene groups containing 1 to 5 carbon atoms.
  • R 2 and R 3 are each independently selected from saturated or unsaturated hydrocarbylene groups containing 1 to 5 carbon atoms.
  • R 2 and R 3 are each independently selected from -CH 2 -, -CH 2 CH 2 -or -CH 2 CH 2 CH 2 -.
  • R 2 is -CH 2 -
  • R 3 is -CH 2 CH 2 -.
  • R 2 and R 3 are both -CH 2 CH 2 -.
  • R 2 is -CH 2 CH 2 -
  • R 3 is -CH 2 CH 2 CH 2 -.
  • R 2 and R 3 are each independently selected from the saturated or unsaturated hydrocarbylene groups containing 1-5 carbon atoms as described above.
  • H may be partially substituted or fully substituted by halogen atoms.
  • the partial substitution here means that the H on the hydrocarbylene group can be substituted with 1-6, 1-5, or 1-3 halogens.
  • the halogen is selected from one or more of F, Cl, Br or I.
  • R 2 and R 3 are each independently selected from the saturated or unsaturated hydrocarbylene groups containing 1-5 carbon atoms as described above.
  • H may be partially substituted or fully substituted by nitro groups.
  • the partial substitution here means that the H on the alkylene group can be substituted with 1-6, 1-5 or 1-3 nitro groups.
  • R 2 and R 3 are each independently selected from the saturated or unsaturated hydrocarbylene groups containing 1-5 carbon atoms as described above.
  • H may be partially substituted or fully substituted by cyano groups.
  • the partial substitution here means that the H on the alkylene group may be substituted by 1-6, 1-5 or 1-3 cyano groups.
  • R 2 and R 3 are each independently selected from the saturated or unsaturated hydrocarbylene groups containing 1-5 carbon atoms as described above.
  • H may be partially substituted or fully substituted by carboxyl groups.
  • the partial substitution here means that the H on the hydrocarbylene group can be substituted with 1-6, 1-5, or 1-3 carboxyl groups.
  • R 2 and R 3 are each independently selected from the saturated or unsaturated hydrocarbylene groups containing 1-5 carbon atoms as described above.
  • H may be partially substituted or fully substituted by sulfonic acid groups.
  • the partial substitution here means that the H on the alkylene group may be substituted by 1-6, 1-5 or 1-3 sulfonic acid groups.
  • the first additive is selected from the following compounds:
  • the first additive can participate in the film formation at the interface between the positive and negative electrodes, and the interface film formed on the positive electrode, the interface film is usually called SEI film, can effectively inhibit the electrolyte from being oxidized and decomposed on the surface of the positive electrode, so that it can prevent electrolysis on the one hand.
  • the product of liquid oxidation and decomposition is deposited on the interface of the positive electrode to increase the interface impedance of the positive electrode. On the other hand, it can also prevent the electrolyte from oxidizing and decomposing at the positive electrode interface to produce gas and causing the interface electrical contact to deteriorate.
  • the second additive is selected from one or more of the compounds represented by formula II:
  • R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , and R 12 are each independently selected from alkyl groups or haloalkyl groups containing 1-6 carbon atoms;
  • the compound of formula II is a borate, a phosphite or a phosphate, respectively.
  • R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , and R 12 are each independently selected from alkyl groups containing 1-6 carbon atoms.
  • alkyl groups containing 1-6 carbon atoms including but not limited to, -CH 3 , -CH 2 CH 3 , -CH 2 CH 2 CH 3 , -CH(CH 3 ) 2 , -CH 2 CH 2 CH 2 CH 3 , -CH(CH 3 )CH 2 CH 3 , -CH 2 CH(CH 3 ) 2 , -C(CH 3 ) 3 , -CH 2 CH 2 CH 2 CH 2 CH 3 , -CH(CH 3 )CH 2 CH 2 CH 3 , -CH 2 CH(CH 3 )CH 2 CH 3 , -CH 2 CH(CH 3 ) 2 , -CH(C 2 H 5 )CH 2 CH 3 , -C(CH 3 ) 2 CH 2 CH 3 , -CH(CH 3
  • R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , and R 12 are independently selected from -CH 3 , -CH 2 CH 3 ,- CH 2 CH 2 CH 3 or -CH 2 CH 2 CH 2 CH 3 .
  • R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , and R 12 are each independently selected from -CH 3 .
  • R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 are each independently selected from haloalkyl groups containing 1-6 carbon atoms, That is, part or all of the hydrogen atoms of the above-mentioned alkyl groups are substituted by halogen atoms.
  • the partial substitution here means that the H on the alkyl group may be substituted with 1-6, 1-5 or 1-3 halogens.
  • the halogen is selected from one or more of F, Cl, Br or I.
  • the second additive is selected from one or more of the compounds represented by formula II-1, formula II-2, and formula II-3:
  • R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , and R 12 are as defined above.
  • the second additive is selected from one or more of the following compounds:
  • Compound 2-12 Tris(tri-n-butylsilane) phosphate.
  • the second additive is selected from the following compounds:
  • the second additive can undergo a complex exchange reaction with the main components in the SEI film formed at the negative electrode interface, which helps to form a more stable SEI film at the negative electrode interface, and significantly reduces the impedance of the negative electrode interface, so that the lithium ion battery Has good power performance.
  • the first additive can form a film on the interface between the positive and negative electrodes to prevent the electrolyte from being oxidized and decomposed, effectively inhibit the generation of gas inside the lithium ion battery, and can further prevent the second Additives are oxidized and decomposed at high temperatures.
  • the second additive is preferentially reduced to the negative electrode to form a film, which can improve the high resistance of the first additive to the negative electrode interface, effectively reduce the reference DC resistance (DCR, Direct Current Resistance) increase during the use of the lithium ion battery, and improve the lithium ion The power performance of the battery.
  • DCR Direct Current Resistance
  • the lithium-ion battery can have better high-temperature cycle performance, high-temperature storage performance and lower low-temperature DC impedance, so that the lithium-ion battery has both good high-temperature performance and low-temperature performance.
  • the performance improvement is also not obvious; and when the content is higher than 3wt%, the impedance after complexing on the cathode will be too large, which will increase the membrane resistance of the cathode active material layer and the electrolyte interface, thereby deteriorating the battery performance. Therefore, in an embodiment of the present application, the concentration of the first additive in the electrolyte is 0.1 wt% to 3 wt%.
  • the concentration of the first additive in the electrolyte may be 0.1% by weight, 0.2% by weight, 0.5% by weight, 1% by weight, 1.5% by weight, 2% by weight, 2.5% by weight, or 3% by weight. Any value and all ranges and subranges. For example, 0.5 wt% to 3 wt%, 0.5 wt% to 2 wt%, 1 wt% to 1.5 wt%, 1 wt% to 2 wt%, and so on.
  • the concentration of the second additive in the electrolyte is 0.05 wt% to 2 wt%.
  • the concentration of the second additive in the electrolyte may be 0.05wt%, 0.1wt%, 0.2wt%, 0.5wt%, 1wt%, 1.5wt% or 2wt%, etc., including any value therein and All ranges and sub-ranges.
  • the type of organic solvent used in the present application is not specifically limited, and can be appropriately selected according to actual needs, as long as the technical solution of the present application can be realized.
  • the organic solvent is selected from ethylene carbonate, propylene carbonate, butylene carbonate, fluoroethylene carbonate, ethyl methyl carbonate, dimethyl carbonate, and diethyl carbonate. Ester, dipropyl carbonate, methyl propyl carbonate, ethylene propyl carbonate, 1,4-butyrolactone, methyl propionate, methyl butyrate, ethyl acetate, ethyl propionate, ethyl butyrate One or more.
  • the organic solvent can also be selected from methyl acrylate, dimethyl sulfite, diethyl sulfite, acid anhydride, N-methylpyrrolidone, N-methylformamide, N -One or more of methylacetamide, acetonitrile, N,N-dimethylformamide, dimethylsulfoxide, methyl sulfide, and tetrahydrofuran.
  • the organic solvent is a mixed solvent of two or more kinds
  • their ratio is not particularly limited, and can be appropriately selected according to actual needs, as long as the technical solution of the present application can be realized.
  • the organic solvent when they contains two different organic solvents, they can be in a mass ratio of 1:1, 2:8, 3:7, 4:6, 8:2, 7: 3, 6:4 equal proportions to mix and use.
  • the content of the organic solvent in the electrolyte is not specifically limited, and can be appropriately selected according to actual needs, as long as the technical solution of the present application can be realized.
  • the content of the organic solvent in the electrolyte is 65 wt% to 85 wt%; optionally, the content of the organic solvent in the electrolyte is 70 wt% ⁇ 80wt%.
  • the content of the organic solvent in the electrolyte may be 65 wt%, 70 wt%, 75 wt%, 80 wt%, 85 wt%, etc., including any value and all ranges and subranges therein.
  • the electrolyte lithium salt used in the present application is not specifically limited, and can be appropriately selected according to actual needs, as long as the technical solution of the present application can be realized.
  • the electrolyte lithium salt may be selected from complex lithium salts of Lewis acid and LiF.
  • LiPF 6 , LiBF 4 , LiAsF 6 , or LiPF 6 , LiBF 4 selected from LiPF 6 , LiBF 4 , LiAsF 6 , LiSbF 6 , LiPF 4 (CF 3 ) 2 , LiPF 3 (C 2 F 5 ) 3 , LiPF 3 (CF 3 ) 3 , LiPF 3 (iso-C 3 F 7 )
  • LiPF 6 , LiBF 4 , LiAsF 6 , or LiPF 6 , LiBF 4 LiPF 6 , LiBF 4 .
  • the electrolyte lithium salt may also be selected from imine or methylated lithium salt.
  • imine or methylated lithium salt selected from LiN(SO 2 F) 2 , LiN(SO 2 CF 3 ) 2 , LiN(SO 2 C 2 F 5 ) 2 , (CF 2 ) 2 (SO 2 ) 2 NLi (cyclic), (CF 2 ) 3 (SO 2 ) 2
  • LiN(SO 2 F) 2 LiN(SO 2 CF 3 ) 2
  • LiN(SO 2 C 2 F 5 ) 2 LiN(SO 2 F 5 ) 2
  • LiN(SO 2 F) 2 and/or LiN(SO 2 CF 3 ) 2 LiN(SO 2 F) 2 and/or LiN(SO 2 CF 3 ) 2 .
  • LiPFMSP pentafluoro((methylsulfonyl)oxy) lithium phosphate
  • LiPO 2 F 2 , Li 2 PO 3 F and LiClO 4 , and LiPO 2 F 2 and/or Li 2 PO 3 F can be selected.
  • the electrolyte lithium salt can also be selected from lithium salts with an oxalate ligand as an anion.
  • lithium salts with an oxalate ligand as an anion.
  • LiBOB and/or LiPFO lithium tetrafluoro[oxalate-O,O']phosphate, LiBOB and/or LiPFO can be selected.
  • the electrolyte lithium salt can also be selected from LiPF 6 , LiPO 2 F 2 , Li 2 PO 3 F, LiBF 4 , LiSO 3 F, LiTFMSB, LiN(SO 2 F) 2 , LiN( One or more of SO 2 CF 3 ) 2 , LiN(SO 2 C 2 F 5 ) 2 , LiBOB, LiPFO and lithium tetrafluoro[oxalate-O,O']phosphate, LiPF 6 , LiBF 4 are optional One or more of LiSO 3 F, LiTFMSB, LiPO 2 F 2 , LiN(SO 2 CF 3 ) 2 , LiN(SO 2 F) 2 , LiBOB, and LiPFO, and LiPF 6 is more optional.
  • the concentration of the electrolyte lithium salt in the electrolyte is not specifically limited, and can be appropriately selected according to actual needs, as long as the technical solution of the present application can be realized.
  • the concentration of the electrolyte lithium salt in the electrolyte is 0.5M, 0.8M, 1.0M, 1.2M, 1.5M, or 2.0M, including any value and all ranges and subranges therein.
  • the lithium ion battery of the second aspect of the present application includes a positive electrode, a negative electrode, a separator, and the electrolyte solution according to any embodiment of the first aspect of the present application.
  • the positive electrode is not specifically limited, and can be appropriately selected according to actual needs, and can be those positive electrodes commonly used in lithium ion batteries, as long as the technical solution of the present application can be realized.
  • the positive electrode includes a positive electrode active material that can extract and accept lithium ions.
  • the positive active material is selected from lithium transition metal composite oxides, including, but not limited to, lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, and lithium nickel cobalt oxide.
  • Aluminum oxides, these lithium transition metal oxides are compounds obtained by adding other transition metals or non-transition metals, and a mixture of one or more of the above substances.
  • the negative electrode is not specifically limited, and can be appropriately selected according to actual needs, and can be those negative electrodes commonly used in lithium ion batteries, as long as the technical solution of the present application can be realized.
  • the negative electrode includes a negative electrode active material that can accept and extract lithium ions.
  • the negative active material is selected from soft carbon, hard carbon, artificial graphite, natural graphite, silicon, silicon-oxygen compound, silicon-carbon composite, lithium titanate, metals that can form an alloy with lithium, and the like.
  • the material of the isolation membrane is not limited and can be selected according to actual needs.
  • the isolation film is a 12 ⁇ m polyethylene film (PE).
  • the positive electrode needs to be further processed into a positive pole piece for use.
  • the structure and preparation method of the positive pole piece are known in the art.
  • the positive electrode active material, conductive agent, binder, etc. are uniformly mixed in an organic solvent, and then coated on a metal (for example, Al foil), dried, and cold pressed to obtain a positive electrode pole piece.
  • the negative electrode needs to be further processed into a negative electrode piece for use.
  • the structure and preparation method of the negative electrode piece are known in the art.
  • the negative electrode active material, conductive agent, binder, etc. are uniformly mixed in an organic solvent, coated on a metal (for example, Cu foil), dried and cold pressed to obtain a negative electrode piece.
  • the conductive agent, binder, and organic solvent are all conventional reagents used in lithium ion batteries, and will not be repeated here.
  • Fig. 1 shows a battery 5 with a square structure as an example.
  • the outer package may include a housing 51 and a cover 53.
  • the housing 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity.
  • the housing 51 has an opening communicating with the containing cavity, and a cover plate 53 can cover the opening to close the containing cavity.
  • the positive pole piece, the negative pole piece and the separator may be formed into the electrode assembly 52 through a winding process or a lamination process.
  • the electrode assembly 52 is packaged in the receiving cavity.
  • the electrolyte is infiltrated in the electrode assembly 52.
  • the number of electrode assemblies 52 included in the battery 5 can be one or several, which can be adjusted according to requirements.
  • the lithium-ion battery After the electrolyte of the present application is applied to a lithium-ion battery, the lithium-ion battery can have better high-temperature cycle performance, high-temperature storage performance, and lower low-temperature DC impedance, so that the lithium-ion battery has both good high-temperature performance and low-temperature performance. performance.
  • the reason is that the bis-nitrile in the sulfur-containing bis-nitrile compound complexes with the positive electrode to reduce the side reaction of the interface at high temperature and inhibit the high temperature gas production of the secondary battery.
  • the sulfur-containing group can form a film on the positive electrode, which greatly reduces the bis-nitrile
  • the impedance when complexed on the surface of the positive electrode but because the reduction potential of sulfur-containing bisnitrile is higher than that of organic solvents, it will form lithium sulfite at the negative electrode interface.
  • the nitrile group of sulfur-containing bisnitrile has strong electron-withdrawing characteristics and is easy to The negative electrode obtains electrons and undergoes a reduction reaction, and its reduction products are unstable and deposit on the negative electrode, which affects the cycle performance of the secondary battery.
  • the silane additive can form a film on the surface of the negative electrode to improve the composition of the SEI film and effectively reduce the negative electrode interface impedance . Therefore, a secondary injection solution is used to make the battery. Firstly, only the first electrolyte containing the silane compound additive is injected in the formation stage, and then the second electrolyte containing the sulfur-containing bisnitrile compound additive is injected in the capacity stage.
  • the additive of silane compound can preferentially form a film on the surface of the negative electrode, inhibiting the side reaction of the additive of sulfur-containing bisnitrile compound in the negative electrode.
  • the third aspect of the application provides a battery module.
  • the lithium ion battery provided in the second aspect of the application can be assembled to the battery module of the third aspect of the application.
  • the number of batteries contained in the battery module can be multiple, and the specific number can be based on the battery
  • the application and capacity of the module can be adjusted.
  • FIG. 3 is a battery module 4 as an example.
  • a plurality of batteries 5 may be arranged in sequence along the length direction of the battery module 4. Of course, it can also be arranged in any other manner. Further, the plurality of batteries 5 can be fixed by fasteners.
  • the battery module 4 may further include a housing with a accommodating space, and a plurality of batteries 5 are accommodated in the accommodating space.
  • the fourth aspect of the present application provides a battery pack.
  • the battery module provided in the third aspect of the present application can also be assembled into the battery pack.
  • the number of battery modules contained in the battery pack can be adjusted according to the application and capacity of the battery pack.
  • FIGS 4 and 5 show the battery pack 1 as an example. 4 and 5, the battery pack 1 may include a battery box and a plurality of battery modules 4 provided in the battery box.
  • the battery box includes an upper box body 2 and a lower box body 3.
  • the upper box body 2 can be covered on the lower box body 3 and forms a closed space for accommodating the battery module 4.
  • a plurality of battery modules 4 can be arranged in the battery box in any manner.
  • a fifth aspect of the present application provides a device that includes at least one of the lithium ion battery, battery module, or battery pack of the present application.
  • the lithium ion battery, battery module or battery pack can be used as the power source of the device, and can also be used as the energy storage unit of the device.
  • the device can be, but is not limited to, mobile devices (such as mobile phones, laptop computers, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf Vehicles, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.
  • the device can select a lithium ion battery, battery module or battery pack according to its usage requirements.
  • Fig. 6 is a device as an example.
  • the device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc.
  • battery packs or battery modules can be used.
  • the device may be a mobile phone, a tablet computer, a notebook computer, and the like.
  • the device usually requires lightness and thinness, and can use lithium-ion batteries as a power source.
  • the lithium ion battery containing the electrolyte of the present application of Examples 1-21 was prepared according to the following method.
  • the positive electrode active material LiNi 0.5 Mn 0.3 Co 0.2 O 2 , the conductive agent acetylene black, and the binder polyvinylidene fluoride (PVDF) are fully stirred and mixed in the N-methylpyrrolidone solvent system at a weight ratio of 94:3:3. Afterwards, it is coated on the Al foil, dried, and cold pressed to obtain a positive pole piece.
  • SBR binder styrene-butadiene rubber
  • CMC thickener sodium carbon methyl cellulose
  • Lithium hexafluorophosphate is added to the organic solvent to obtain a lithium salt with a concentration of 1.0 mol/L, and then the first additive and the second additive are respectively added to the organic solvent, and after they are mixed uniformly, the electrolyte A and the electrolyte B are obtained.
  • a 12 ⁇ m polyethylene film (PE) is used as the separator.
  • PE polyethylene film
  • the prepared soft-packed lithium ion battery has a thickness of 4.0 mm, a width
  • the preparation method of the lithium ion battery of Comparative Examples 1-19 is basically similar to that of Examples 1-21, except that only electrolyte B or A is added during the preparation of the lithium ion battery.
  • the capacity retention rate of the lithium ion battery after 1,000 cycles (%) (discharge capacity at the 1,000th cycle/discharge capacity at the first cycle) ⁇ 100%.
  • the volume expansion rate (%) of a lithium-ion battery stored at 80°C for 30 days (V1-V0)/V0 ⁇ 100%.
  • the capacity retention rate (%) of the lithium ion battery after being stored at 60°C for 120 days C1/C0 ⁇ 100%.
  • SOC state of charge
  • the DCR of a lithium ion battery at 25°C is equal to (U1-U2)/I, where I represents the current.
  • Table 1 shows the performance test results of the lithium ion batteries of Examples 1-9 and Comparative Examples 1-8.

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Abstract

本申请实施例提供一种电解液、包含该电解液的锂离子电池、电池模块、电池包及装置。本申请实施例中的电解液包括有机溶剂、溶解在该有机溶剂中的电解质锂盐以及添加剂，其中所述添加剂包括第一添加剂和第二添加剂。所述第一添加剂选自式I所示的化合物中的一种或多种，所述第二添加剂选自式II所示的化合物中的一种或多种。本申请的电解液应用于锂离子电池后，使得锂离子电池在高温下具有较好的循环性能和存储性能，在低温下具有较低的直流阻抗，从而使锂离子电池兼具较好的高温性能和低温性能。

Description

电解液、包含该电解液的锂离子电池、电池模块、电池包及装置
相关申请的交叉引用
本申请要求享有于2019年09月10日提交的名称为“电解液及包含该电解液的锂离子电池”的中国专利申请201910854407.3的优先权，该申请的全部内容通过引用并入本文中。
技术领域
本申请涉及电池领域，尤其涉及一种电解液、包含该电解液的锂离子电池、电池模块、电池包及装置。
背景技术
随着消费类电子产品和可充电电池作为动力系统的新能源汽车飞速发展，人们对电池的要求也越来越高。锂电池相比铅酸电池、镍氢电池、镍镉电池具有高比能量密度、宽工作温度范围以及长循环寿命的优点，使其在市场上长期占据着主流地位。
随着锂离子电池的广泛应用，对其环境适应性也提出了更高的要求，然而现在的电子产品有时须在温度很高或者很低的环境中使用，相对常规环境而言，锂离子电池在极端条件下使用时性能会明显恶化。
电解液作为锂离子电池的重要组成部分，对锂离子电池的高、低温 性能有着重大的影响，然而电解液同时改善锂离子电池的高温性能和低温性能是很难的。一方面，通过引入成膜添加剂来钝化正极虽然可以改善锂离子电池的高温性能，但常规的添加剂会恶化正极的阻抗，使得锂离子电池在低温下的功率性能较差；另一方面，优化电解液溶剂组成配比，使得电解液在低温下的粘度降低来改善低温性能，但这种方法会恶化锂离子电池的高温产气，不能有效地解决锂离子电池在极端条件下的应用问题。
发明内容
本申请的第一方面提供一种电解液，包括：有机溶剂，溶解在所述有机溶剂中的电解质锂盐，以及添加剂；所述添加剂包括第一添加剂和第二添加剂；其中所述第一添加剂选自式I所示的化合物中的一种或多种：
Figure PCTCN2020113973-appb-000001
式I所示的化合物中R1选自-S(＝O) 2-、-O-S(＝O) 2-O-、-O-S(＝O) 2-、-O-S(＝O)-O-或1,1-二氧代-四氢噻吩-3,4-基，R 2和R 3各自独立地选自含1-10个碳原子的饱和或不饱和的亚烃基，所述亚烃基上的H可被卤素、硝基、氰基、羧基、磺酸基部分取代或全部取代；
所述第二添加剂选自式II所示的化合物中的一种或多种：
Figure PCTCN2020113973-appb-000002
其中R 4、R 5、R 6、R 7、R 8、R 9、R 10、R 11、R 12分别独立地选自含1-6个碳原子的烷基或卤代烷基；X表示B、P或P＝O；
可以理解的是，当X表示B、P或P＝O时，式II的化合物分别为硼酸酯、亚磷酸酯或磷酸酯。
在第一添加剂以及第二添加剂两者的协同作用下，可使锂离子电池具有较好的高温循环性能、高温存储性能以及较低的低温直流阻抗，从而使锂离子电池兼具较好的高温性能和低温性能。
在上述任意实施方式中，R 1选自-S(＝O) 2-、-O-S(＝O) 2-O-、-O-S(＝O) 2-、-O-S(＝O)-O-或1,1-二氧代-四氢噻吩-3,4-基，R 2和R 3各自独立地选自含1-5个碳原子的饱和或不饱和的亚烃基。
在上述任意实施方式中，R 2和R 3各自独立地选自-CH 2-、-CH 2CH 2-或-CH 2CH 2CH 2-。
在上述任意实施方式中，所述第一添加剂选自下述化合物中的一种或多种：
Figure PCTCN2020113973-appb-000003
第一添加剂可以在正负极界面参与成膜，其在正极形成的界面膜，可以有效抑制电解液在正极表面被氧化分解，这样一方面可以减少正极的界面阻抗，另一方面优化正极界面的电接触。
在上述任意实施方式中，所述第二添加剂选自下述化合物中的一种或多种：
Figure PCTCN2020113973-appb-000004
其中R 4、R 5、R 6、R 7、R 8、R 9、R 10、R 11、R 12分别独立地选自含1-6个碳原子的烷基或卤代烷基。
在上述任意实施方式中，R 4、R 5、R 6、R 7、R 8、R 9、R 10、R 11、R 12分别独立地选自-CH 3、-CH 2CH 3、-CH 2CH 2CH 3或-CH 2CH 2CH 2CH 3。
在上述任意实施方式中，所述第二添加剂选自下述化合物中的一种或多种：
化合物2-1：三(三甲基硅烷)亚磷酸酯，
化合物2-2：三(三甲基硅烷)硼酸酯，
化合物2-3：三(三乙基硅烷)亚磷酸酯，
化合物2-4：三(三正丙基硅烷)亚磷酸酯，
化合物2-5：三(三正丁基硅烷)亚磷酸酯，
化合物2-6：三(三乙基硅烷)硼酸酯，
化合物2-7：三(三正丙基硅烷)硼酸酯，
化合物2-8：三(三正丁基硅烷)硼酸酯，
化合物2-9：三(三甲基硅烷)磷酸酯，
化合物2-10：三(三乙基硅烷)磷酸酯，
化合物2-11：三(三正丙基硅烷)磷酸酯，
化合物2-12：三(三正丁基硅烷)磷酸酯。
第二添加剂可与在负极界面形成的界面膜中的主要成分发生复杂的交换反应，有助于在负极界面形成更稳定的界面膜，并显著地降低负极界面的阻抗，使锂离子电池具有良好的功率性能。
在上述任意实施方式中，所述第一添加剂在所述电解液中的浓度为0.1wt％～3wt％。可阻止电解液进一步反应，避免阴极活性物质层与电解质界面的膜电阻上升，改善电池性能。
在上述任意实施方式中，所述第二添加剂在所述电解液中的浓度为0.05wt％～2wt％。可阻止第一添加剂在负极表面的还原成膜，改善锂离子电池的循环性能，利于锂离子在钝化膜中的传输，优化锂离子电池的性能。
在上述任意实施方式中，所述电解质锂盐选自：LiPF 6、LiPO 2F 2、Li 2PO 3F、LiBF 4、LiSO 3F、LiTFMSB、LiN(SO 2F) 2、LiN(SO 2CF 3) 2、LiN(SO 2C 2F 5) 2、LiBOB、LiPFO和四氟[草酸根-O,O’]磷酸锂中的一种或多种；可选地，所述电解质锂盐选自：LiPF 6、LiBF 4、LiSO 3F、LiTFMSB、LiPO 2F 2、LiN(SO 2CF 3) 2、LiN(SO 2F) 2、LiBOB和LiPFO中的一种或多种。
在上述任意实施方式中，所述电解质锂盐在电解液中的浓度为0.5M～2M；可选地，所述电解质锂盐在电解液中的浓度为0.8M～1.2M。
本申请的第二方面提供一种锂离子电池，锂离子电池包括正极、负极、隔离膜，以及上述本申请第一方面的电解液。
本申请的第三方面提供一种电池模块，上述的锂离子电池。
本申请的第四方面提供一种电池包，上述的电池模块。
本申请的第五方面提供一种装置，包括上述的锂离子电池、上述的电池模块或上述的电池包中的至少一种。
附图说明
为了更清楚地说明本申请实施例的技术方案，下面将对本申请实施例中所需要使用的附图作简单地介绍，显而易见地，下面所描述的附图仅仅是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据附图获得其他的附图。
图1是电池的一实施方式的示意图。
图2是图1的分解图。
图3是电池模块的一实施方式的示意图。
图4是电池包的一实施方式的示意图。
图5是图4的分解图。
图6是装置的一实施方式的示意图。
具体实施方式
下面结合附图和实施例对本申请的实施方式作进一步详细描述。以下实施例的详细描述和附图用于示例性地说明本申请的原理，但不能用来限制本申请的范围，即本申请不限于所描述的实施例。
在本申请的描述中，需要说明的是，除非另有说明，“多个”的含义是两个以上；术语“上”、“下”、“左”、“右”、“内”、“外”等指示的方位或位置关系仅是为了便于描述本申请和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本申请的限制。此外，术语“第一”、“第二”、“第三”等仅用于描述目的，而不能理解为指示或暗示相对重要性。“垂直”并不是严格意义上的垂直，而是在误差允许范围之内。“平行”并不是严格意义上的平行，而是在误差允许范围之内。
下述描述中出现的方位词均为图中示出的方向，并不是对本申请的具体结构进行限定。在本申请的描述中，还需要说明的是，除非另有明确的规定和限定，术语“安装”、“相连”、“连接”应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或一体地连接；可以是直接相连，也 可以通过中间媒介间接相连。对于本领域的普通技术人员而言，可视具体情况理解上述术语在本申请中的具体含义。
为了简便，本文仅明确地公开了一些数值范围。然而，任意下限可以与任何上限组合形成未明确记载的范围；以及任意下限可以与其它下限组合形成未明确记载的范围，同样任意上限可以与任意其它上限组合形成未明确记载的范围。此外，尽管未明确记载，但是范围端点间的每个点或单个数值都包含在该范围内。因而，每个点或单个数值可以作为自身的下限或上限与任意其它点或单个数值组合或与其它下限或上限组合形成未明确记载的范围。
在本文的描述中，需要说明的是，除非另有说明，“以上”、“以下”为包含本数，“一种或几种”中“几种”的含义是两种或两种以上。
上述发明内容并不意欲描述本申请中的每个公开的实施方式或每种实现方式。如下描述更具体地举例说明示例性实施方式。在整篇申请中的多处，通过一系列实施例提供了指导，这些实施例可以以各种组合形式使用。在各个实例中，列举仅作为代表性组，不应解释为穷举。
首先，下文将详细描述根据本申请第一方面的电解液。
根据本申请第一方面的电解液，包括有机溶剂、溶解在该有机溶剂中的电解质锂盐以及添加剂，其中所述添加剂包括第一添加剂和第二添加剂。
所述第一添加剂选自式I所述的化合物中的一种或多种：
Figure PCTCN2020113973-appb-000005
其中R 1选自-S(＝O) 2-、-O-S(＝O) 2-O-、-O-S(＝O) 2-、-O-S(＝O)-O-或1,1-二氧四氢噻吩-3,4-基
Figure PCTCN2020113973-appb-000006
R 2和R 3各自独立地选自含1-10个碳原子的饱和或不饱和的亚烃基，所述亚烃基上的H可被卤素、硝基、氰基、羧基、磺酸基部分取代或全部取代。
在本申请一实施例中，R 1选自-S(＝O) 2-。
在本申请一实施例中，R 1选自-O-S(＝O) 2-O-。
在本申请一实施例中，R 1选自-O-S(＝O) 2-。
在本申请一实施例中，R 1选自-O-S(＝O)-O-。
在本申请一实施例中，R 1选自1,1-二氧代-四氢噻吩-3,4-基。
在本申请一实施例中，R 2和R 3各自独立地选自含1-5个碳原子的饱和或不饱和的亚烃基。例如，包括但不限于，-CH 2-、-CH 2CH 2-、-CH 2CH 2CH 2-、-C(CH 3) 2-、-CH 2CH 2CH 2CH 2-、-CH(CH 3)CH 2CH 2-、-CH 2CH(CH 3) 2-、-CH 2CH 2CH 2CH 2CH 2-、-CH(CH 3)CH 2CH 2CH 2-、-CH 2CH(CH 3)CH 2CH 2-、-CH 2CH 2C(CH 3) 2-、-CH(C 2H 5)CH 2CH 2-、-C(CH 3) 2CH 2CH 2-、-CH(CH 3)C(CH 3) 2-等，或者将前述基团中的一个或多个单键替换为双键、三键的不饱和亚烃基。
在本申请一实施例中，R 2和R 3各自独立地选自-CH 2-、-CH 2CH 2-或-CH 2CH 2CH 2-。
在本申请一实施例中，R 2为-CH 2-，R 3为-CH 2CH 2-。
在本申请一实施例中，R 2和R 3均为-CH 2CH 2-。
在本申请一实施例中，R 2为-CH 2CH 2-，R 3为-CH 2CH 2CH 2-。
在本申请一实施例中，R 2和R 3各自独立地选自如上文所述的含1-5个碳原子的饱和或不饱和的亚烃基，所述饱和或不饱和的亚烃基上的H可被卤素原子部分取代或全部取代。这里的部分取代是指所述亚烃基上的H可被1-6个、可被1-5个或可被1-3个卤素取代。所述卤素选自F、Cl、Br或I中的一个或多个。
在本申请一实施例中，R 2和R 3各自独立地选自如上文所述的含1-5个碳原子的饱和或不饱和的亚烃基，所述饱和或不饱和的亚烃基上的H可被硝基部分取代或全部取代。这里的部分取代是指所述亚烃基上的H可被1-6个、可被1-5个或可被1-3个硝基取代。
在本申请一实施例中，R 2和R 3各自独立地选自如上文所述的含1-5个碳原子的饱和或不饱和的亚烃基，所述饱和或不饱和的亚烃基上的H可被氰基部分取代或全部取代。这里的部分取代是指所述亚烃基上的H可被1-6个、可被1-5个或可被1-3个氰基取代。
在本申请一实施例中，R 2和R 3各自独立地选自如上文所述的含1-5个碳原子的饱和或不饱和的亚烃基，所述饱和或不饱和的亚烃基上的H可被羧基部分取代或全部取代。这里的部分取代是指所述亚烃基上的H可被1-6个、可被1-5个或可被1-3个羧基取代。
在本申请一实施例中，R 2和R 3各自独立地选自如上文所述的含1-5个碳原子的饱和或不饱和的亚烃基，所述饱和或不饱和的亚烃基上的H可被磺酸基部分取代或全部取代。这里的部分取代是指所述亚烃基上的H可被1-6个、可被1-5个或可被1-3个磺酸基取代。
在本申请一实施例中，所述第一添加剂选自下述化合物：
Figure PCTCN2020113973-appb-000007
所述第一添加剂可以在正负极界面参与成膜，其在正极形成的界面膜，该界面膜通常称作SEI膜，可以有效抑制电解液在正极表面被氧化分解，这样一方面可以防止电解液氧化分解的产物沉积于正极界面而增大正极的界面阻抗，另一方面还可以防止电解液在正极界面氧化分解产气而导致界面电接触变差。
所述第二添加剂选自式II所示的化合物中的一种或多种：
Figure PCTCN2020113973-appb-000008
Figure PCTCN2020113973-appb-000009
其中R 4、R 5、R 6、R 7、R 8、R 9、R 10、R 11、R 12分别独立地选自含1-6个碳原子的烷基或卤代烷基；X表示B、P或P＝O；
可以理解的是，当X表示B、P或P＝O时，式II的化合物分别为硼酸酯、亚磷酸酯或磷酸酯。
在本申请一实施例中，R 4、R 5、R 6、R 7、R 8、R 9、R 10、R 11、R 12分别独立地选自含1-6个碳原子的烷基。例如，包括但不限于，-CH 3、-CH 2CH 3、-CH 2CH 2CH 3、-CH(CH 3) 2、-CH 2CH 2CH 2CH 3、-CH(CH 3)CH 2CH 3、-CH 2CH(CH 3) 2、-C(CH 3) 3、-CH 2CH 2CH 2CH 2CH 3、-CH(CH 3)CH 2CH 2CH 3、-CH 2CH(CH 3)CH 2CH 3、-CH 2CH 2CH(CH 3) 2、-CH(C 2H 5)CH 2CH 3、-C(CH 3) 2CH 2CH 3、-CH(CH 3)CH(CH 3) 2、-CH 2C(CH 3) 3。
在本申请一实施例中，R 4、R 5、R 6、R 7、R 8、R 9、R 10、R 11、R 12分别独立地选自-CH 3、-CH 2CH 3、-CH 2CH 2CH 3或-CH 2CH 2CH 2CH 3。
在本申请一实施例中，R 4、R 5、R 6、R 7、R 8、R 9、R 10、R 11、R 12分别独立地选自-CH 3。
在本申请一实施例中，R 4、R 5、R 6、R 7、R 8、R 9、R 10、R 11、R 12分别独立地选自含1-6个碳原子的卤代烷基，即上文所述的烷基的氢原子部分或全部被卤素原子取代。这里的部分取代是指所述烷基上的H可被1-6个、可被1-5个或可被1-3个卤素取代。所述卤素选自F、Cl、Br或I中的一个或多个。
在本申请一实施例中，所述第二添加剂选自式II-1、式II-2、式II-3所示的化合物中的一种或多种：
Figure PCTCN2020113973-appb-000010
其中，R 4、R 5、R 6、R 7、R 8、R 9、R 10、R 11、R 12如上文所定义。
在本申请一实施例中，所述第二添加剂选自下述化合物的一种或多种：
化合物2-1：三(三甲基硅烷)亚磷酸酯，
化合物2-2：三(三甲基硅烷)硼酸酯，
化合物2-3：三(三乙基硅烷)亚磷酸酯，
化合物2-4：三(三正丙基硅烷)亚磷酸酯，
化合物2-5：三(三正丁基硅烷)亚磷酸酯，
化合物2-6：三(三乙基硅烷)硼酸酯，
化合物2-7：三(三正丙基硅烷)硼酸酯，
化合物2-8：三(三正丁基硅烷)硼酸酯，
化合物2-9：三(三甲基硅烷)磷酸酯，
化合物2-10：三(三乙基硅烷)磷酸酯，
化合物2-11：三(三正丙基硅烷)磷酸酯，
化合物2-12：三(三正丁基硅烷)磷酸酯。
在本申请一实施例中，所述第二添加剂选自下述化合物：
化合物2-1：三(三甲基硅烷)亚磷酸酯，
化合物2-2：三(三甲基硅烷)硼酸酯。
Figure PCTCN2020113973-appb-000011
所述第二添加剂可与在负极界面形成的SEI膜中的主要成分发生复杂的交换反应，有助于在负极界面形成更稳定的SEI膜，并显著地降低负极界面的阻抗，使锂离子电池具有良好的功率性能。
将所述第一添加剂和第二添加剂联合使用后，第一添加剂可以在正负极界面成膜，防止电解液被氧化分解，有效抑制锂离子电池内部气体的产生，同时还可以进一步阻止第二添加剂在高温下被氧化分解。第二添加剂优先在负极还原成膜，可以改善第一添加剂在负极界面成膜阻抗较高的缺点，有效降低锂离子电池使用过程中的参考直流电阻(DCR,Directive Current Resistance)增长，改善锂离子电池的功率性能。因此在两者的协同作用下，可使锂离子电池具有较好的高温循环性能、高温存储性能以及较低的低温直流阻抗，从而使锂离子电池兼具较好的高温性能和低温性能。
进一步地，发明人发现，当所述第一添加剂在所述电解液中的含量低于0.1wt％时，由于含量过少，形成的阴极钝化膜并不足以阻止电解液进一步反应，对电池性能的改善也不明显；而当含量高于3wt％时，在阴极上络合后的阻抗过大，会使阴极活性物质层与电解质界面的膜电阻上升，从而恶化电池性能。因此，在本申请一实施例中，所述第一添加剂在所述电解液中的浓度为0.1wt％～3wt％。例如，所述第一添加剂在所述电解 液中的浓度可以是0.1wt％、0.2wt％、0.5wt％、1wt％、1.5wt％、2wt％、2.5wt％或3wt％等，包括其中的任何数值及所有范围和子范围。例如0.5wt％～3wt％、0.5wt％～2wt％、1wt％～1.5wt％、1wt％～2wt％等。
进一步地，发明人发现，当所述第二添加剂在所述电解液中的含量太低时,如低于0.05wt％时，其无法阻止第一添加剂在负极表面的还原成膜，从而会恶化锂离子电池的循环性能；当第二添加剂在电解液中的含量较高时，例如高于2wt％时，其会在正、负极表面形成过厚的钝化膜，使得钝化膜的阻抗较高，不利于锂离子在钝化膜中的传输，增加了电池极化，反而会恶化锂离子电池的性能。因此，在本申请一实施例中，所述第二添加剂在所述电解液中的浓度为0.05wt％～2wt％。例如，所述第二添加剂在所述电解液中的浓度可以是0.05wt％、0.1wt％、0.2wt％、0.5wt％、1wt％、1.5wt％或2wt％等，包括其中的任何数值及所有范围和子范围。例如0.05wt％～2wt％、0.5wt％～1.5wt％、0.5wt％～2wt％、1wt％～1.5wt％、1wt％～2wt％等。
用于本申请的有机溶剂的种类没有具体限制，可根据实际需求适当选择，只要能够实现本申请的技术方案即可。作为例举，在本申请一实施例中，所述有机溶剂选自碳酸乙烯酯、碳酸丙烯酯、碳酸丁烯酯、氟代碳酸乙烯酯、碳酸甲乙酯、碳酸二甲酯、碳酸二乙酯、碳酸二丙酯、碳酸甲丙酯、碳酸乙丙酯、1,4-丁内酯、丙酸甲酯、丁酸甲酯、乙酸乙酯、丙酸乙酯、丁酸乙酯中的一种或多种。
在本申请另一实施例中，所述有机溶剂还可选自丙烯酸甲酯、亚硫酸二甲酯、二乙基亚硫酸酯、酸酐、N-甲基吡咯烷酮、N-甲基甲酰胺、N-甲基乙酰胺、乙腈、N,N-二甲基甲酰胺、二甲亚砜、甲硫醚、四氢呋喃中的一种或几种。
当所述有机溶剂为两种或更多种的混合溶剂时，它们的比例没有特别限制，可根据实际需求适当选择，只要能够实现本申请的技术方案即可。例如，在本申请一实施例中，当所述有机溶剂包含两种不同有机溶剂时，它们可以按照质量比1:1、2:8、3:7、4:6、8:2、7:3、6:4等比例来混合使用。
所述有机溶剂在电解液中的含量没有具体限制，可根据实际需求适当选择，只要能够实现本申请的技术方案即可。作为例举，在本申请一实施例中，所述有机溶剂在所述电解液中的含量为65wt％～85wt％；可选地，所述有机溶剂在所述电解液中的含量为70wt％～80wt％。例如所述有机溶剂在所述电解液中的含量可以是65wt％、70wt％、75wt％、80wt％、85wt％等，包括其中的任何数值及所有范围和子范围。
同样地，用于本申请的电解质锂盐没有具体限制，可根据实际需求适当选择，只要能够实现本申请的技术方案即可。在本申请一实施例中，所述电解质锂盐可选自路易斯酸与LiF的络合锂盐。例如，选自LiPF 6、LiBF 4、LiAsF 6、LiSbF 6、LiPF 4(CF 3) 2、LiPF 3(C 2F 5) 3、LiPF 3(CF 3) 3、LiPF 3(异-C 3F 7) 3和LiPF 5(异-C 3F 9)的一种或多种，可选LiPF 6、LiBF 4、LiAsF 6，也可选LiPF 6、LiBF 4。
在本申请一实施例中，所述电解质锂盐还可选自亚胺或甲基化的锂盐。例如，选自LiN(SO 2F) 2、LiN(SO 2CF 3) 2、LiN(SO 2C 2F 5) 2、(CF 2) 2(SO 2) 2NLi(环状)、(CF 2) 3(SO 2) 2NLi(环状)和LiC(SO 2CF 3) 3中的一种或多种，可选LiN(SO 2F) 2、LiN(SO 2CF 3) 2和/或LiN(SO 2C 2F 5) 2，也可选LiN(SO 2F) 2和/或LiN(SO 2CF 3) 2。
在本申请一实施例中，所述电解质锂盐还可选自含有S(＝O) 2O结构的锂盐。例如，选自LiSO 3F、LiCF 3SO 3、CH 3SO 4Li、C 2H 5SO 4Li、 C 3H 7SO 4Li、三氟((甲磺酰)氧基)硼酸锂(LiTFMSB)、和五氟((甲磺酰)氧基)磷酸锂(LiPFMSP)中的一种或多种，可选LiSO 3F、CH 3SO 4Li、C 2H 5SO 4Li和/或LiTFMSB。
在本申请一实施例中，所述电解质锂盐还可选自含有P＝O或Cl＝O结构的锂盐。例如，选自LiPO 2F 2、Li 2PO 3F和LiClO 4中的一种或多种，可选LiPO 2F 2和/或Li 2PO 3F。
在本申请一实施例中，所述电解质锂盐还可选自以草酸盐配位体为阴离子的锂盐。例如，双[草酸根-O,O’]硼酸锂(LiBOB)、二氟[草酸根-O,O’]硼酸锂、二氟双[草酸根-O,O’]磷酸锂(LiPFO)和四氟[草酸根-O,O’]磷酸锂中的一种或多种，可选LiBOB和/或LiPFO。
在本申请一实施例中，所述电解质锂盐还可选自LiPF 6、LiPO 2F 2、Li 2PO 3F、LiBF 4、LiSO 3F、LiTFMSB、LiN(SO 2F) 2、LiN(SO 2CF 3) 2、LiN(SO 2C 2F 5) 2、LiBOB、LiPFO和四氟[草酸根-O,O’]磷酸锂中的一种或多种，可选LiPF 6、LiBF 4、LiSO 3F、LiTFMSB、LiPO 2F 2、LiN(SO 2CF 3) 2、LiN(SO 2F) 2、LiBOB和LiPFO中的一种或多种，更可选LiPF 6。
所述电解质锂盐在电解液中的浓度没有具体限制，可根据实际需求适当选择，只要能够实现本申请的技术方案即可。在本申请一实施例中，所述电解质锂盐在电解液中的浓度为0.5M～2M(M＝mol·L -1)，可选0.8M～1.2M。例如，所述电解质锂盐在电解液中的浓度为0.5M、0.8M、1.0M、1.2M、1.5M或2.0M，包括其中的任何数值及所有范围和子范围。例如0.5M～2M、0.5M～1.5M、0.8M～1.2M、1.0M～2.0M、1.0M～1.5M等。
接下来将详细描述根据本申请第二方面的锂离子电池。
本申请第二方面的锂离子电池包括正极、负极、隔离膜，以及根 据上述本申请第一方面的任何实施例的电解液。
所述正极没有具体限制，可根据实际需求适当选择，可以是通常用于锂离子电池的那些正极，只要能够实现本申请的技术方案即可。作为示例，在本申请一实施例中，所述正极包含能脱出、接受锂离子的正极活性物质。所述正极活性物质选自锂过渡金属复合氧化物，包括但不限于，锂钴氧化物、锂镍氧化物、锂锰氧化物、锂镍锰氧化物、锂镍钴锰氧化物、锂镍钴铝氧化物，这些锂过渡金属氧化物添加其他过渡金属或非过渡金属得到的化合物，以及上述物质的一种或几种的混合物等。
所述负极没有具体限制，可根据实际需求适当选择，可以是通常用于锂离子电池的那些负极，只要能够实现本申请的技术方案即可。作为示例，在本申请一实施例中，所述负极包含能接受、脱出锂离子的负极活性物质。所述负极活性物质选自软碳、硬碳、人造石墨、天然石墨、硅、硅氧化合物、硅碳复合物、钛酸锂，能与锂形成合金的金属等。
所述隔离膜的材质不受限制，可以根据实际需求进行选择。在本申请一实施例中，所述隔离膜为12μm的聚乙烯薄膜(PE)。
通常在具体应用中，需要将所述正极进一步加工成正极极片使用，所述正极极片的构造和制备方法是本领域已知的。例如，将所述正极活性物质、导电剂、粘结剂等在有机溶剂中混合均匀，凃敷于金属(例如Al箔)上经烘干、冷压，即可制得正极极片。
同样地，在具体应用中，需要将所述负极进一步加工成负极极片使用，所述负极极片的构造和制备方法是本领域已知的。例如，将所述负极活性物质、导电剂、粘结剂等在有机溶剂中混合均匀，凃敷于金属(例如Cu箔)上经烘干、冷压，即可制得负极极片。
所述导电剂、粘结剂、有机溶剂均为用于锂离子电池的常规试 剂，在此不再赘述。
本申请对锂离子电池的形状没有特别的限制，其可以是圆柱形、方形或其他任意的形状。如图1是作为一个示例的方形结构的电池5。
在一些实施方式中，参照图2，外包装可包括壳体51和盖板53。其中，壳体51可包括底板和连接于底板上的侧板，底板和侧板围合形成容纳腔。壳体51具有与容纳腔连通的开口，盖板53能够盖设于所述开口，以封闭所述容纳腔。正极极片、负极极片和隔离膜可经卷绕工艺或叠片工艺形成电极组件52。电极组件52封装于所述容纳腔。电解液浸润于电极组件52中。电池5所含电极组件52的数量可以为一个或几个，可根据需求来调节。
本申请的电解液应用于锂离子电池后，可使锂离子电池具有较好的高温循环性能、高温存储性能以及较低的低温直流阻抗，从而使锂离子电池兼具较好的高温性能和低温性能。其原因是含硫双腈类化合物中的双腈与正极络合，减小高温时界面副反应，抑制二次电池高温产气，同时含硫基团能在正极成膜，极大降低双腈在正极表面络合时的阻抗，但由于含硫双腈的还原电位较有机溶剂高，其会在负极界面形成亚硫酸锂，含硫双腈的腈基具有较强的吸电子特性，容易在负极得到电子发生还原反应，且其还原产物不稳定会沉积到负极上，影响二次电池的循环性能。当电解液中添加硅烷磷酸酯化合物、硅烷亚磷酸酯化合物、硅烷硼酸酯化合物中的至少一种后，由于硅烷添加剂能在负极表面成膜，改善SEI膜的组成，有效减小负极界面阻抗。因此制作电芯采用二次注液方案，首先化成阶段只注含有硅烷化合物的添加剂的第一电解液，继而在容量阶段再注含硫双腈化合物的添加剂的第二电解液，这样可以使含有硅烷化合物的添加剂能优先在负极表面成膜，抑制含硫双腈化合物的添加剂在负极的副反应，因此 在含有硅烷化合物的添加剂以及含硫双腈化合物的添加剂的协同作用下，能够同时提高二次电池的高温存储性能、高温循环性能以及低温性能。
本申请第三方面提供一种电池模块，上述本申请第二方面提供的锂离子电池可以组装成本申请第三方面的电池模块，电池模块所含电池的数量可以为多个，具体数量可根据电池模块的应用和容量来调节。
图3是作为一个示例的电池模块4。参照图3，在电池模块4中，多个电池5可以是沿电池模块4的长度方向依次排列设置。当然，也可以按照其他任意的方式进行排布。进一步可以通过紧固件将该多个电池5进行固定。
可选地，电池模块4还可以包括具有容纳空间的外壳，多个电池5容纳于该容纳空间。
本申请第四方面提供一种电池包，本申请第三方面提供的电池模块还可以组装成该电池包，电池包中所含电池模块的数量可以根据电池包的应用和容量进行调节。
图4和图5是作为一个示例的电池包1。参照图4和图5，在电池包1中可以包括电池箱和设置于电池箱中的多个电池模块4。电池箱包括上箱体2和下箱体3，上箱体2能够盖设于下箱体3，并形成用于容纳电池模块4的封闭空间。多个电池模块4可以按照任意的方式排布于电池箱中。
本申请的第五方面提供一种装置，所述装置包括本申请的锂离子电池、电池模块、或电池包中的至少一种。所述锂离子电池、电池模块或电池包可以用作所述装置的电源，也可以作为所述装置的能量存储单元。所述装置可以但不限于是移动设备(例如手机、笔记本电脑等)、电动车辆(例如纯电动车、混合动力电动车、插电式混合动力电动车、电动自行 车、电动踏板车、电动高尔夫球车、电动卡车等)、电气列车、船舶及卫星、储能系统等。
所述装置可以根据其使用需求来选择锂离子电池、电池模块或电池包。
图6是作为一个示例的装置。该装置为纯电动车、混合动力电动车、或插电式混合动力电动车等。为了满足该装置对锂离子电池的高功率和高能量密度的需求，可以采用电池包或电池模块。
作为另一个示例的装置可以是手机、平板电脑、笔记本电脑等。该装置通常要求轻薄化，可以采用锂离子电池作为电源。
实施例
下面结合具体实施例，进一步阐述本申请。应理解，下文的示例性实施例仅用于举例说明，并非对本申请进行限定。除非另有声明，实施例中使用的所有试剂都可商购或按照常规方法进行合成获得，并且可直接使用而无需进一步处理。实施例中未注明的实验条件采用常规条件、或采用材料供应商或设备供应商推荐的条件。
实施例1-21
按照下述方法制备实施例1-21的包含本申请的电解液的锂离子电池。
正极极片和负极极片的制备
将正极活性物质LiNi 0.5Mn 0.3Co 0.2O 2、导电剂乙炔黑、粘结剂聚偏二氟乙烯(PVDF)按重量比94:3:3在N-甲基吡咯烷酮溶剂体系中充分搅拌混合均匀后，涂覆于Al箔上烘干、冷压，得到正极极片。
将负极活性物质人造石墨、导电剂乙炔黑、粘结剂丁苯橡胶 (SBR)、增稠剂碳甲基纤维素钠(CMC)按照重量比95:2:2:1在去离子水溶剂体系中充分搅拌混合均匀后，涂覆于Cu箔上烘干、冷压，得到负极极片。
电解液的制备
在充满氩气的手套箱中，将碳酸乙烯酯(EC)和碳酸二乙酯(DEC)以质量比EC:DEC＝20:80混合，作为有机溶剂。向该有机溶剂中加入六氟磷酸锂，得到浓度为1.0mol/L的锂盐，然后向其中分别加入第一添加剂和第二添加剂，各自混合均匀后，即为所述电解液A和电解液B。
锂离子电池的制备
以12μm的聚乙烯薄膜(PE)作为隔离膜。将制得的正极极片、隔离膜、负极极片按顺序叠好，使隔离膜处于正负极片中间，卷绕得到裸电芯，并焊接极耳，然后将裸电芯置于外包装中，将上述制备的电解液B注入到干燥后的裸电芯中，封装、静置，然后用0.02C恒流充电到3.3V，再以0.1C恒流充电到3.6V，整形；再向整形完后的电芯中注入电解液A，0.33C恒流充电至4.4V，之后4.4V恒压充电至电流为0.05C，然后用1C恒流放电至2.8V，容量测试，完成锂离子电池的制备。制得的软包锂离子电池的厚度4.0mm、宽度60mm、长度140mm。
对比例1-19
对比例1-19的锂离子电池的制备方法与实施例1-21基本类似，除了锂离子电池的制备过程中仅添加电解质B或A之外。
性能测试
锂离子电池的循环性能测试
在45℃下，将锂离子电池以1C恒流充电至4.2V后，之后4.2V 恒压充电至电流为0.05C，然后用1C恒流放电至2.8V，上述为一个充放电循环。然后按照上述条件进行1000次循环充电/放电测试。
锂离子电池循环1000次后的容量保持率(％)＝(第1000次循环的放电容量/首次循环的放电容量)×100％。
锂离子电池的高温存储体积膨胀测试
在25℃下，将锂离子电池静置30分钟，之后以1C恒流充电至电压为4.2V，然后以4.2V恒压充电至电流为0.05C，此时测试锂离子电池的体积并记为V0；然后将满充的锂离子电池放入85℃恒温箱中，存储30天，采用排水法测试体积并记为V1。
锂离子电池80℃存储30天后的体积膨胀率(％)＝(V1-V0)/V0×100％。
锂离子电池的高温存储性能测试
在25℃下，将锂离子电池以1C恒流充电至电压为4.2V，之后以4.2V恒压充电至电流为0.05C，然后以1C恒流放电至电压为2.8V，测试此时锂离子电池的放电容量，记为C0；之后将锂离子电池以1C恒流充电至电压为4.2V，之后以4.2V恒压充电至电流为0.05C，将锂离子电池放入60℃的恒温箱，保温120天，取出锂离子电池，以1C恒流放电至电压为2.8V，测试此时锂离子电池的放电容量，记为C1。
锂离子电池60℃存储120天后的容量保持率(％)＝C1/C0×100％。
锂离子电池的常温直流阻抗(DCR)测试
在25℃下调整锂离子电池的荷电状态(SOC)至满充容量的20％，将锂离子电池置于-25℃的高低温箱中，静置2小时，使锂离子电池温度达 到-25℃，测试此时锂离子电池的电压并记为U1，然后以0.3C的倍率放电10s，测试锂离子电池放电后的电压并记为U2。
锂离子电池25℃的DCR＝(U1-U2)/I，I表示电流。
表1示出了实施例1-9和对比例1-8的锂离子电池的性能测试结果。
表1
Figure PCTCN2020113973-appb-000012
Figure PCTCN2020113973-appb-000013
从对比例1-5的测试结果可以看出，在电解液中加入第一添加剂，锂离子电池的高温循环容量保持率、高温存储体积膨胀率及高温存储 容量保持率得到一定改善，但是锂离子电池的低温直流阻抗增加。从对比例1和对比例6-17的测试结果可以看出，在电解液中加入第二添加剂可显著降低锂离子电池的低温直流阻抗，但是锂离子电池的高温循环容量保持率和高温存储容量保持率恶化明显。
从实施例1-21的测试结果可以看出，在电解液中同时加入第一添加剂和第二添加剂，可使锂离子电池同时具有较高的高温循环容量保持率、高温存储容量保持率以及较低的高温存储体积膨胀率，同时锂离子电池还具有较低的低温直流阻抗，即当第一添加剂与第二添加剂联用时，既可以发挥第一添加剂化合物对锂离子电池高温性能的改善，同时可以避免第二添加剂化合物对低温直流阻抗的恶化。
从实施例1-3和对比例1可知，随着第二添加剂含量增加，高温性能持续改善，但低温阻抗是先降低后增加，这可能是含硫双腈化合物含量过大，导致其在正极络合后钝化层太厚，从而影响在低温时锂离子在正极表面的传输，因此表现出相对较差的低温直流阻抗。
从实施例4-6、对比例5可知，随着第二添加剂含量增加，低温直流阻抗逐渐降低，但含量较高时，高温循环容量保持率和高温存储容量保持率会相对恶化，但仍优于对比例6-17和19。
根据上述说明书的揭示和教导，本领域技术人员还可以对上述实施方式进行变更和修改。因此，本申请并不局限于上面揭示和描述的具体实施方式，对本申请的一些修改和变更也应当落入本申请的权利要求的保护范围内。此外，尽管本说明书中使用了一些特定的术语，但这些术语只是为了方便说明，并不对本申请构成任何限制。
虽然已经参考优选实施例对本申请进行了描述，但在不脱离本申请的范围的情况下，可以对其进行各种改进并且可以用等效物替换其中的 部件。尤其是，只要不存在结构冲突，各个实施例中所提到的各项技术特征均可以任意方式组合起来。本申请并不局限于文中公开的特定实施例，而是包括落入权利要求的范围内的所有技术方案。

Claims (15)

  1. 一种电解液，包括：
    有机溶剂，
    溶解在所述有机溶剂中的电解质锂盐，以及添加剂，
    所述添加剂包括第一添加剂和第二添加剂，其中；
    所述第一添加剂选自式I所示的化合物中的一种或多种：
    Figure PCTCN2020113973-appb-100001
    其中R 1选自-S(＝O) 2-、-O-S(＝O) 2-O-、-O-S(＝O) 2-、-O-S(＝O)-O-或1,1-二氧代-四氢噻吩-3,4-基，R 2和R 3各自独立地选自含1-10个碳原子的饱和或不饱和的亚烃基，所述亚烃基上的H任选被卤素、硝基、氰基、羧基、磺酸基部分取代或全部取代；
    所述第二添加剂选自式II所示的化合物中的一种或多种：
    Figure PCTCN2020113973-appb-100002
    其中R 4、R 5、R 6、R 7、R 8、R 9、R 10、R 11、R 12分别独立地选自含1-6 个碳原子的烷基或卤代烷基；
    可以理解的是，当X表示B、P或P＝O时，式II的化合物分别为硼酸酯、亚磷酸酯或磷酸酯。
  2. 根据权利要求1所述的电解液，其中，R 1选自-S(＝O) 2-、-O-S(＝O) 2-O-、-O-S(＝O) 2-、-O-S(＝O)-O-或1,1-二氧代-四氢噻吩-3,4-基，R 2和R 3各自独立地选自含1-5个碳原子的饱和或亚烃基不饱和的亚烃基。
  3. 根据权利要求1或2所述的电解液，其中，R 2和R 3各自独立地选自-CH 2-、-CH 2CH 2-或-CH 2CH 2CH 2-。
  4. 根据权利要求1至3任一项所述的电解液，其中，所述第一添加剂选自下述化合物中的一种或多种：
    Figure PCTCN2020113973-appb-100003
  5. 根据权利要求1至4任一项所述的电解液，其中，所述第二添加剂 选自下述化合物中的一种或多种：
    Figure PCTCN2020113973-appb-100004
    其中R 4、R 5、R 6、R 7、R 8、R 9、R 10、R 11、R 12分别独立地选自含1-6个碳原子的烷基或卤代烷基。
  6. 根据权利要求1至5任一项所述的电解液，其中，R 4、R 5、R 6、R 7、R 8、R 9、R 10、R 11、R 12分别独立地选自-CH 3、-CH 2CH 3、-CH 2CH 2CH 3或-CH 2CH 2CH 2CH 3。
  7. 根据权利要求1至6任一项所述的电解液，其中，所述第二添加剂选自下述化合物中的一种或多种：
    化合物2-1：三(三甲基硅烷)亚磷酸酯，
    化合物2-2：三(三甲基硅烷)硼酸酯，
    化合物2-3：三(三乙基硅烷)亚磷酸酯，
    化合物2-4：三(三正丙基硅烷)亚磷酸酯，
    化合物2-5：三(三正丁基硅烷)亚磷酸酯，
    化合物2-6：三(三乙基硅烷)硼酸酯，
    化合物2-7：三(三正丙基硅烷)硼酸酯，
    化合物2-8：三(三正丁基硅烷)硼酸酯，
    化合物2-9：三(三甲基硅烷)磷酸酯，
    化合物2-10：三(三乙基硅烷)磷酸酯，
    化合物2-11：三(三正丙基硅烷)磷酸酯，
    化合物2-12：三(三正丁基硅烷)磷酸酯。
  8. 根据权利要求1至7任一项所述的电解液，其中，所述第一添加剂在所述电解液中的浓度为0.1wt％～3wt％。
  9. 根据权利要求1至8任一项所述的电解液，其中，所述第二添加剂在所述电解液中的浓度为0.05wt％～2wt％。
  10. 根据权利要求1至9任一项所述的电解液，其中，所述电解质锂盐选自：LiPF 6、LiPO 2F 2、Li 2PO 3F、LiBF 4、LiSO 3F、LiTFMSB、LiN(SO 2F) 2、LiN(SO 2CF 3) 2、LiN(SO 2C 2F 5) 2、LiBOB、LiPFO和四氟[草酸根-O,O’]磷酸锂中的一种或多种；可选地，所述电解质锂盐选自：LiPF 6、LiBF 4、LiSO 3F、LiTFMSB、LiPO 2F 2、LiN(SO 2CF 3) 2、LiN(SO 2F) 2、LiBOB和LiPFO中的一种或多种。
  11. 根据权利要求1至10任一项所述的电解液，其中，所述电解质锂盐在电解液中的浓度为0.5M～2M；可选地，所述电解质锂盐在电解液中的浓度为0.8M～1.2M。
  12. 一种锂离子电池，包括正极、负极、隔离膜，以及根据权利要求1-11任一项所述的电解液。
  13. 一种电池模块，包括权利要求12所述的锂离子电池。
  14. 一种电池包，包括权利要求13所述的电池模块。
  15. 一种装置，包括权利要求12所述的锂离子电池、权利要求13所述的电池模块或权利要求14所述的电池包中的至少一种。
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