WO2021120434A1 - 一种电解液及电化学装置 - Google Patents

一种电解液及电化学装置 Download PDF

Info

Publication number
WO2021120434A1
WO2021120434A1 PCT/CN2020/080596 CN2020080596W WO2021120434A1 WO 2021120434 A1 WO2021120434 A1 WO 2021120434A1 CN 2020080596 W CN2020080596 W CN 2020080596W WO 2021120434 A1 WO2021120434 A1 WO 2021120434A1
Authority
WO
WIPO (PCT)
Prior art keywords
electrolyte
weight
compound
cyclic
content
Prior art date
Application number
PCT/CN2020/080596
Other languages
English (en)
French (fr)
Inventor
许艳艳
徐春瑞
郑建明
唐超
Original Assignee
宁德新能源科技有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 宁德新能源科技有限公司 filed Critical 宁德新能源科技有限公司
Priority to JP2020518426A priority Critical patent/JP7311497B2/ja
Priority to KR1020207012674A priority patent/KR102563223B1/ko
Publication of WO2021120434A1 publication Critical patent/WO2021120434A1/zh

Links

Classifications

    • 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
    • H01M10/0567—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
    • H01M10/05—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
    • 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
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic electrolyte
    • H01M2300/0028—Organic electrolyte characterised by the solvent
    • H01M2300/0037—Mixture of solvents
    • H01M2300/004—Three solvents
    • 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 energy storage technology, and in particular to an electrolyte, an electrochemical device including the electrolyte, and an electronic device including the electrochemical device.
  • Lithium-ion batteries are a new generation of green and environmentally friendly batteries developed in the 1990s. They have the advantages of high working voltage, large specific energy, long cycle life, environmental friendliness, and no memory effect. They are widely used in new energy electric vehicles. , 3C electronic products, portable electronic equipment, power tools, energy storage, military, aerospace and other fields. However, with the continuous expansion of lithium-ion battery applications and the continuous development of modern information technology, people have higher requirements for the battery energy density and safety performance of lithium-ion batteries.
  • the present application provides an electrolytic solution, an electrochemical device containing the electrolytic solution, and an electronic device containing the electrochemical device, wherein the electrolytic solution contains a fluoroethylene carbonate and a silicate compound. Adding a specific ratio of fluoroethylene carbonate and silicate compounds to the electrolyte is beneficial to form a stable interface protection layer on the surface of the positive and negative electrodes, thereby significantly improving the cycle life and high-temperature storage performance of lithium-ion batteries.
  • the present application provides an electrolyte, which includes a fluoroethylene carbonate and a silicate compound.
  • the structure of the silicate compound is as shown in Formula I:
  • R 1 , R 2 , R 3 and R 4 are each independently selected from substituted or unsubstituted C 1 to C 10 hydrocarbon groups, wherein when substituted, the substituent is halogen, wherein the silicate compound and the The mass ratio of fluoroethylene carbonate is 1:1 to 1:10.
  • the silicate compound in the electrolyte, includes:
  • the content of the silicate compound is about 0.1% to about 5% by weight of the total weight of the electrolyte.
  • the electrolyte further includes a cyclic carboxylic anhydride compound, wherein the cyclic carboxylic anhydride compound has at least one of the structure of Formula II, Formula III, or Formula IV:
  • R 5 , R 6 , R 7 , R 8 , R 9 , R 10 and R 11 are each independently selected from: hydrogen, halogen and substituted or unsubstituted C 1 ⁇ C 10 hydrocarbon groups, wherein when substituted, the substituent is halogen.
  • the content of the cyclic carboxylic anhydride is about 0.1% to about 5% by weight of the total weight of the electrolyte.
  • the cyclic carboxylic anhydride includes maleic anhydride, succinic anhydride, 2-methyl succinic anhydride, 2,3-dimethyl succinic anhydride, or glutaric anhydride. At least one.
  • the electrolyte further comprises a disulfonate compound of formula V:
  • n is an integer from 1 to 4.
  • the content of the disulfonate compound is about 0.1% to about 5% by weight of the total weight of the electrolyte.
  • the disulfonate compound is selected from methylene disulfonate.
  • the electrolyte further includes the following additives: at least one of LiPO 2 F 2 , unsaturated cyclic carbonate, cyclic sultone, cyclic sulphuric acid lactone or nitrile compound .
  • the content of the additive is about 0.001% to about 13% by weight of the total weight of the electrolyte; wherein,
  • the content of the LiPO 2 F 2 is about 0.001% to about 2% by weight of the total weight of the electrolyte;
  • the unsaturated cyclic carbonate includes at least one of vinylene carbonate or vinyl ethylene carbonate, and the content of the unsaturated cyclic carbonate is about 0.001% to about 2% by weight of the total weight of the electrolyte. weight%;
  • the cyclic sultone includes at least one of 1,3-propane sultone, 1,4-butane sultone or 1,3-propene sultone, and the cyclic sultone
  • the content of acid lactone is about 0.01 wt% to about 3 wt% of the total weight of the electrolyte;
  • the cyclic sulphuric acid lactone includes at least one of vinyl sulphate, propylene sulphate or 4-methyl ethylene sulphate; the content of the cyclic sulphuric acid lactone is 0.01% by weight of the total weight of the electrolyte To 3% by weight, and
  • the nitrile compound includes succinonitrile, glutaronitrile, adiponitrile, 2-methyleneglutaronitrile, dipropylmalononitrile, 1,3,6-hexanetrinitrile, 1,2,6- At least one of hexanetrinitrile, 1,3,5-pentanetrinitrile, or 1,2-bis(cyanoethoxy)ethane, the content of the nitrile compound is about the total weight of the electrolyte 0.5% to about 7% by weight.
  • the present application provides an electrochemical device, which includes any of the foregoing electrolytes.
  • the present application provides an electronic device, which includes the electrochemical device described above.
  • the terms “approximately”, “substantially”, “substantially” and “about” are used to describe and illustrate small changes.
  • the term may refer to an example in which the event or situation occurs precisely and an example in which the event or situation occurs very closely.
  • the term can refer to a range of variation less than or equal to ⁇ 10% of the numerical value, such as less than or equal to ⁇ 5%, less than or equal to ⁇ 4%, less than or equal to ⁇ 3 %, less than or equal to ⁇ 2%, less than or equal to ⁇ 1%, less than or equal to ⁇ 0.5%, less than or equal to ⁇ 0.1%, or less than or equal to ⁇ 0.05%.
  • the difference between two values is less than or equal to ⁇ 10% of the average value of the value (for example, less than or equal to ⁇ 5%, less than or equal to ⁇ 4%, less than or equal to ⁇ 3%, less than Or equal to ⁇ 2%, less than or equal to ⁇ 1%, less than or equal to ⁇ 0.5%, less than or equal to ⁇ 0.1%, or less than or equal to ⁇ 0.05%), then the two values can be considered "substantially" the same.
  • a list of items connected by the terms “at least one of”, “at least one of”, “at least one of” or other similar terms may mean the listed items Any combination of. For example, if items A and B are listed, then the phrases “at least one of A and B" and “at least one of A or B” mean only A; only B; or A and B. In another example, if items A, B, and C are listed, then the phrases “at least one of A, B, and C" and "at least one of A, B, or C” mean only A; or only B; C only; A and B (exclude C); A and C (exclude B); B and C (exclude A); or all of A, B, and C.
  • Project A can contain a single component or multiple components.
  • Project B can contain a single component or multiple components.
  • Item C can contain a single component or multiple components.
  • hydrocarbyl encompasses alkyl, alkenyl, and alkynyl groups.
  • the hydrocarbyl group is expected to be a straight chain hydrocarbon structure having 1 to 10 carbon atoms.
  • the "hydrocarbyl group” is also expected to be a branched or cyclic hydrocarbon structure having 3 to 10 carbon atoms. When a hydrocarbyl group having a specific carbon number is designated, it is expected to encompass all geometric isomers having that carbon number.
  • the hydrocarbyl group herein may also be a hydrocarbyl group of 1 to 8 carbon atoms, a hydrocarbyl group of 1 to 6 carbon atoms, or a hydrocarbyl group of 1 to 4 carbon atoms.
  • the hydrocarbyl group may be optionally substituted.
  • the hydrocarbyl group may be substituted with halogen or alkyl including fluorine, chlorine, bromine, and iodine.
  • alkyl is intended to be a linear saturated hydrocarbon structure having 1 to 10 carbon atoms. "Alkyl” is also expected to be a branched or cyclic hydrocarbon structure having 3 to 10 carbon atoms.
  • the alkyl group may be an alkyl group of 1 to 8 carbon atoms, an alkyl group of 1 to 6 carbon atoms, or an alkyl group of 1 to 4 carbon atoms.
  • an alkyl group having a specific carbon number it is expected to encompass all geometric isomers having that carbon number.
  • butyl means to include n-butyl, sec-butyl, isobutyl, tert-butyl, and cyclobutyl;
  • propyl includes n-propyl, isopropyl and cyclopropyl.
  • alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, cyclopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, cyclobutyl, n-pentyl, Isopentyl, neopentyl, cyclopentyl, methylcyclopentyl, ethylcyclopentyl, n-hexyl, isohexyl, cyclohexyl, n-heptyl, octyl, cyclopropyl, cyclobutyl, norbornyl Base and so on.
  • the alkyl group may be optionally substituted.
  • alkenyl refers to a monovalent unsaturated hydrocarbon group that can be straight or branched and has at least one and usually 1, 2, or 3 carbon-carbon double bonds. Unless otherwise defined, the alkenyl group usually contains 2 to 10 carbon atoms, for example, it may be an alkenyl group of 6 to 10 carbon atoms, an alkenyl group of 2 to 8 carbon atoms, or an alkenyl group of 2 to 6 carbon atoms. base.
  • Representative alkenyl groups include, for example, vinyl, n-propenyl, isopropenyl, n-but-2-enyl, but-3-enyl, n-hex-3-enyl, and the like. In addition, alkenyl groups may be optionally substituted.
  • alkynyl refers to a monovalent unsaturated hydrocarbon group that may be linear or branched and has at least one and usually 1, 2, or 3 carbon-carbon triple bonds. Unless otherwise defined, the alkynyl group usually contains 2 to 10 carbon atoms, for example, it can be an alkynyl group of 6 to 10 carbon atoms, an alkynyl group of 2 to 8 carbon atoms, or an alkynyl group of 2 to 6 carbon atoms. Alkynyl.
  • alkynyl groups include, for example, ethynyl, prop-2-ynyl (n-propynyl), n-but-2-ynyl, n-hex-3-ynyl, and the like. In addition, alkynyl groups may be optionally substituted.
  • halogen can be F, Cl, Br, or I.
  • the present application provides an electrolyte containing fluoroethylene carbonate (FEC) and a silicate compound.
  • FEC fluoroethylene carbonate
  • the structure of the silicate compound is shown in Formula I:
  • R 1 , R 2 , R 3 and R 4 are each independently selected from a substituted or unsubstituted C 1 to C 10 hydrocarbon group, a substituted or unsubstituted C 1 to C 6 hydrocarbon group, or a substituted or unsubstituted C 1 ⁇ C 4 hydrocarbon group, wherein when substituted, the substituent is halogen.
  • R 1 , R 2 , R 3 and R 4 are each independently selected from substituted or unsubstituted C 1 to C 4 alkyl groups, wherein when substituted, the substituent is halogen.
  • R 1 , R 2 , R 3 and R 4 are each independently selected from methyl, ethyl, or propyl.
  • the silicate compound of formula I is selected from at least one of the following compounds 1 to 3:
  • the silicate compound of Formula I is tetraethyl silicate (Compound 1).
  • the mass ratio of the silicate compound to the fluoroethylene carbonate (FEC) is about 1:1 to about 1:10. In some embodiments, the mass ratio of the silicate compound to the fluoroethylene carbonate (FEC) is or about 1:2 to about 1:6. In some embodiments, the silicate compound The mass ratio to the fluoroethylene carbonate (FEC) is about 1:3 to about 1:5. In some embodiments, the mass ratio is about 1:2, about 1:3, about 1:4, about 1:5, about 1:6, or about 1:7.
  • Adding a silicate compound and a fluoroethylene carbonate to the electrolyte, and the two are in the above range, can stabilize the electrolyte, and at the same time, form a dense protective layer on the surface of the positive electrode to improve the cycle performance and rate performance of the battery.
  • the content of the silicate compound is about 0.1% to about 5% by weight of the total weight of the electrolyte. In some embodiments, the content of the silicate compound is about 0.5% to about 4% by weight of the total weight of the electrolyte. In some embodiments, the content of the silicate compound is about 1% to about 3% by weight of the total weight of the electrolyte. In some embodiments, the content of the silicate compound is about 1.5% to about 2% by weight of the total weight of the electrolyte. In some embodiments, the content of the silicate compound is about 0.5% by weight, about 1% by weight, about 1.5% by weight, about 2% by weight, about 2.5% by weight, or about 3% by weight of the total weight of the electrolyte.
  • the content is less than 0.1% by weight, the improvement of the stability of the electrolyte is limited. When it is greater than 5% by weight, the positive electrode film is too thick, which affects Li + transmission and deteriorates the cell impedance and cycle performance.
  • the electrolyte further includes a cyclic carboxylic anhydride compound, wherein the cyclic carboxylic anhydride compound has at least one of the structure of Formula II, Formula III, or Formula IV:
  • R 5 , R 6 , R 7 , R 8 , R 9 , R 10 and R 11 are each independently selected from: hydrogen, halogen, substituted or unsubstituted C 1 to C 10 hydrocarbon group, substituted or unsubstituted C 1 to C 6 hydrocarbon group, or substituted or unsubstituted C 1 to C 4 hydrocarbon group, wherein when substituted, the substituent is halogen.
  • R 5 , R 6 , R 7 , R 8 , R 9 , R 10 and R 11 are each independently selected from substituted or unsubstituted C 1 to C 4 alkyl groups, wherein when substituted, substituted The radical is halogen.
  • R 5 , R 6 , R 7 , R 8 , R 9 , R 10 and R 11 are each independently selected from hydrogen or methyl.
  • the cyclic carboxylic acid anhydride includes at least one of maleic anhydride, succinic anhydride, 2-methylsuccinic anhydride, 2,3-dimethylsuccinic anhydride, or glutaric anhydride.
  • the content of the cyclic carboxylic anhydride accounts for about 0.1% to about 5% by weight of the total weight of the electrolyte; in some embodiments, the content of the cyclic carboxylic anhydride accounts for the total weight of the electrolyte.
  • the content of the cyclic carboxylic anhydride accounts for about 1% to about 3% by weight of the total weight of the electrolyte; in some embodiments Wherein, the content of the cyclic carboxylic anhydride accounts for about 1.5% to about 2% by weight of the total weight of the electrolyte; in some embodiments, the content of the cyclic carboxylic anhydride accounts for about 0.5% of the total weight of the electrolyte.
  • % By weight, about 1% by weight, about 1.5% by weight, about 2% by weight, about 2.5% by weight, about 3% by weight, about 3.5% by weight, or about 4% by weight.
  • the cyclic carboxylic anhydride When the cyclic carboxylic anhydride is added to the above electrolyte, due to the higher reduction potential of the cyclic carboxylic anhydride, it can be further preferentially reduced to a dense SEI film on the negative electrode, and the SEI formed by the silicate compound and FEC is further modified. Makes Li + easy to shuttle, and further improves the battery's rate and cycle performance.
  • the content of the cyclic carboxylic acid anhydride is too low to form a stable protection at the negative electrode interface, and the effect of improving the cycle performance is not achieved; when the content of the cyclic carboxylic acid anhydride is too high, the film thickness will be too large, thereby This causes the battery capacity to decrease and the battery impedance to increase.
  • the electrolyte in the electrolyte, it further comprises a disulfonate compound of formula V: Wherein n is an integer from 1 to 4.
  • the disulfonate compound is selected from methylene disulfonate (MMDS).
  • the content of the disulfonate compound accounts for about 0.1% to about 5% by weight of the total weight of the electrolyte; in some embodiments, the content of the disulfonate compound accounts for all About 0.5% to about 4% by weight of the total weight of the electrolyte; in some embodiments, the content of the disulfonate compound accounts for about 1% to about 3% by weight of the total weight of the electrolyte; In some embodiments, the content of the disulfonate compound accounts for about 1.5% by weight to about 2% by weight of the total weight of the electrolyte; in some embodiments, the disulfonate compound accounts for about 2% by weight of the electrolyte.
  • Adding the disulfonate to the above electrolyte can form an SEI film with excellent stability on the positive electrode, further inhibiting the elution of transition metals in the positive electrode material and reducing direct contact with the electrolyte, thereby further improving the rate performance of the battery And cycle performance.
  • the electrolyte further includes the following additives: at least one of unsaturated cyclic carbonate, cyclic sultone, cyclic sulfuric acid lactone, nitrile compound, or LiPO 2 F 2 .
  • the unsaturated cyclic carbonate includes at least one of vinylene carbonate (VC) or vinyl ethylene carbonate (VEC);
  • the cyclic sultone includes 1,3- At least one of propane sultone (PS), 1,4-butane sultone (BS), or 1,3-propene sultone (PST);
  • the cyclic sulphuric acid lactone includes sulfuric acid At least one of vinyl ester (DTD), propylene sulfate, or 4-methyl ethylene sulfate;
  • the nitrile compound includes succinonitrile (SN), glutaronitrile, adiponitrile, 2-methylene Glutaronitrile, dipropylmalononitrile, 1,3,6-hexanetrin
  • the content of the additive accounts for about 0.1% to about 13% by weight of the total weight of the electrolyte; in some embodiments, the content of the additive accounts for about 0.5% of the total weight of the electrolyte. In some embodiments, the content of the additive accounts for about 0.5% to about 8% by weight of the total weight of the electrolyte; in some embodiments, the content of the additive accounts for all The total weight of the electrolyte is about 1% to about 7% by weight; in some embodiments, the content of the additive accounts for about 1.5% to about 6% by weight of the total weight of the electrolyte; in some embodiments The additive accounts for about 0.5% by weight, about 1% by weight, about 1.5% by weight, about 2% by weight, about 2.5% by weight, about 3% by weight, about 3.5% by weight, and about 4% by weight of the total weight of the electrolyte.
  • the content of the LiPO 2 F 2 is about 0.1% to about 2% by weight of the total weight of the electrolyte; in some embodiments, the content of the LiPO 2 F 2 is equal to that of the electrolytic solution. About 0.1% to about 1% by weight of the total weight of the liquid; in some embodiments, the content of the LiPO 2 F 2 is about 0.1% to about 0.6% by weight of the total weight of the electrolyte.
  • the content of the unsaturated cyclic carbonate is about 0.01% to about 2% by weight of the total weight of the electrolyte; in some embodiments, the content of the unsaturated cyclic carbonate It is about 0.01% to about 1.5% by weight of the total weight of the electrolyte; in some embodiments, the content of the unsaturated cyclic carbonate is about 0.01% to about 1% by weight of the total weight of the electrolyte. %.
  • the content of the cyclic sultone is about 0.01% to about 3% by weight of the total weight of the electrolyte; in some embodiments, the content of the cyclic sultone is It is about 0.1% to about 2% by weight of the total weight of the electrolyte; in some embodiments, the content of the cyclic sultone is about 0.5% to about 1.5% by weight of the total weight of the electrolyte. %;
  • the content of the cyclic sulphuric acid lactone is about 0.01% to about 3% by weight of the total weight of the electrolyte; in some embodiments, the content of the cyclic sulphuric acid lactone is The total weight of the electrolyte is about 0.1% to about 2% by weight; in some embodiments, the content of the cyclic sulfuric acid lactone is about 0.5% to about 1.5% by weight of the total weight of the electrolyte.
  • the content of the nitrile compound is about 0.5% to about 7% by weight of the total weight of the electrolyte; in some embodiments, the content of the nitrile compound is about the total weight of the electrolyte. In some embodiments, the content of the nitrile compound is about 0.5% to about 3% by weight of the total weight of the electrolyte; in some embodiments, the nitrile compound The content of is about 1 wt% to about 2 wt% of the total weight of the electrolyte.
  • the electrolyte solution further includes an organic solvent and a lithium salt.
  • the organic solvent comprises a cyclic ester and a chain ester
  • the mass ratio of the cyclic ester to the chain ester is about 1:9 to about 7:3
  • the cyclic ester is selected from ethylene carbonate At least one of (EC), propylene carbonate (PC), ⁇ -butyrolactone (BL), ethylene carbonate substituted with fluorine-containing groups, or propylene carbonate
  • the chain ester is selected from dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), ethyl acetate (EA), methyl formate (MF), ethyl formate (MA), ethyl propionate (EP), propylene At least one of propyl acid (PP), methyl butyrate (MB), ethyl methyl fluorocarbonate, ethyl fluoropropionate, and the like.
  • DMC dimethyl carbonate
  • DEC diethyl carbonate
  • the content of the organic solvent is about 60% to about 95% by weight of the total weight of the electrolyte; in some embodiments, the content of the organic solvent is about the total weight of the electrolyte. About 60% to about 90% by weight. In some embodiments, the content of the organic solvent is about 70% to about 85% by weight of the total weight of the electrolyte.
  • the lithium salt is at least one of an organic lithium salt or an inorganic lithium salt.
  • the lithium salt contains at least one of fluorine, boron, and phosphorus.
  • the lithium salt is selected from lithium hexafluorophosphate (LiPF 6 ), lithium difluorophosphate, lithium bistrifluoromethanesulfonimide LiN(CF 3 SO 2 ) 2 , lithium bis(fluorosulfonyl)imide Li(N(SO 2 F) 2 , lithium bisoxalate borate LiB (C 2 O 4 ) 2 , lithium difluorooxalate borate LiBF 2 (C 2 O 4 ), lithium hexafluoroarsenate (LiAsF 6 ), perchloric acid At least one of lithium (LiClO 4 ) and lithium trifluoromethanesulfonate (LiCF 3 SO 3 ).
  • the lithium salt may be lithium hexafluorophosphate.
  • the concentration of the lithium salt is about 0.5mol/L to about 1.8mol/L. In some embodiments, the concentration of the lithium salt is about 0.8mol/L to about 1.5mol/L. In some embodiments, the concentration of the lithium salt is about 0.8mol/L to about 1mol/L.
  • the electrochemical device of the present application may include any device that undergoes an electrochemical reaction, and specific examples thereof include all kinds of primary batteries, secondary batteries, fuel cells, solar cells, or capacitors.
  • the electrochemical device is a lithium secondary battery, including a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, or a lithium ion polymer secondary battery.
  • the electrochemical device of the present application includes a positive electrode having a positive electrode active material capable of occluding and releasing metal ions; a negative electrode having a negative electrode active material capable of occluding and releasing metal ions; placed between the positive electrode and the negative electrode The isolation membrane; and the electrolyte of this application.
  • the electrolyte used in the electrochemical device of the present application is any of the above-mentioned electrolytes in the present application.
  • the electrolytic solution used in the electrochemical device of the present application may also include other electrolytic solutions within the scope not departing from the gist of the present application.
  • the material of the positive electrode used in the electrochemical device of the present application can be prepared using materials, structures, and manufacturing methods known in the art.
  • the technology described in US9812739B can be used to prepare the positive electrode of the present application, which is incorporated into the present application by reference in its entirety.
  • the positive electrode includes a current collector and a positive electrode active material layer on the current collector.
  • the positive electrode active material includes at least one lithiated intercalation compound that reversibly intercalates and deintercalates lithium ions.
  • the positive active material includes a composite oxide.
  • the composite oxide contains lithium and at least one element selected from cobalt, manganese, and nickel.
  • the positive electrode active material is selected from lithium nickel cobalt manganese (NCM) ternary materials, lithium iron phosphate (LiFePO 4 ), LiCoO 2 , LiNiO 2 , LiMn 2 O 4 , LiCo 1-y M y O 2 , LiNi 1-y M y O 2 , LiMn 2-y M y O 4 , LiNi x Co y Mn z M 1-xyz O 2 , where M is selected from Fe, Co, Ni, Mn, Mg, Cu, Zn, One or more of Al, Sn, B, Ga, Cr, Sr, V, Ti, and 0 ⁇ y ⁇ 1, 0 ⁇ x ⁇ 1, 0 ⁇ z ⁇ 1, x+y+z ⁇ 1 or Any combination of them.
  • NCM lithium nickel cobalt manganese
  • LiFePO 4 lithium iron phosphate
  • the positive active material may have a coating on its surface, or may be mixed with another compound having a coating.
  • the coating may include at least one selected from the oxide of the coating element, the hydroxide of the coating element, the oxyhydroxide of the coating element, the oxycarbonate of the coating element, and the hydroxycarbonate of the coating element kind of coating element compound.
  • the compound used for the coating may be amorphous or crystalline.
  • the coating element contained in the coating may include Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, P, or these Any combination of.
  • the coating in the coating layer may be AlPO 4 , Mg 3 (PO 4 ) 2 , Co 3 (PO 4 ) 2 , AlF 3 , MgF 2 , CoF 3 , NaF, B 2 O 3 At least one of them.
  • the content of the coating element in the coating is about 0.01 wt% to about 10 wt%.
  • the coating can be applied by any method as long as the method does not adversely affect the performance of the positive electrode active material.
  • the method may include any coating method known in the art, such as spraying, dipping, and the like.
  • the positive active material layer further includes a binder, and optionally a conductive material.
  • the binder improves the bonding of the positive electrode active material particles to each other, and also improves the bonding of the positive electrode active material to the current collector.
  • the binder includes, but is not limited to: polyvinyl alcohol, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene-containing Oxygen polymers, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene butadiene rubber, acrylic (ester) styrene butadiene rubber, epoxy resin, Nylon etc.
  • conductive materials include, but are not limited to: carbon-based materials, metal-based materials, conductive polymers, and mixtures thereof.
  • the carbon-based material is selected from natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanotube, graphene, or any combination thereof.
  • the metal-based material is selected from metal powder, metal fiber, copper, nickel, aluminum, silver.
  • the conductive polymer is a polyphenylene derivative.
  • the current collector may be aluminum, but is not limited thereto.
  • the positive electrode can be prepared by a preparation method known in the art.
  • the positive electrode can be obtained by mixing an active material, a conductive material, and a binder in a solvent to prepare an active material composition, and coating the active material composition on a current collector.
  • the solvent may include N-methylpyrrolidone and the like, but is not limited thereto.
  • the positive electrode is made by forming a positive electrode material using a positive electrode active material layer including lithium transition metal-based compound powder and a binder on a current collector.
  • the positive active material layer can usually be made by the following operations: dry mixing the positive electrode material and the binder (conducting material and thickener used as needed) to form a sheet, The obtained sheet is press-bonded to the positive electrode current collector, or these materials are dissolved or dispersed in a liquid medium to prepare a slurry, which is coated on the positive electrode current collector and dried.
  • the material of the positive active material layer includes any material known in the art.
  • the material, composition, and manufacturing method of the negative electrode used in the electrochemical device of the present application may include any technology disclosed in the prior art.
  • the negative electrode is the negative electrode described in U.S. Patent Application US9812739B, which is incorporated in this application by reference in its entirety.
  • the negative electrode includes a current collector and a negative active material layer on the current collector.
  • the negative electrode active material includes a material that reversibly intercalates/deintercalates lithium ions.
  • the material that reversibly intercalates/deintercalates lithium ions includes a carbon material.
  • the carbon material may be any carbon-based negative active material commonly used in lithium ion rechargeable batteries.
  • the carbon material includes, but is not limited to: crystalline carbon, amorphous carbon, or a mixture thereof.
  • the crystalline carbon may be amorphous, flake-shaped, flake-shaped, spherical or fibrous natural graphite or artificial graphite.
  • Amorphous carbon may be soft carbon, hard carbon, mesophase pitch carbide, calcined coke, and the like.
  • the negative active material layer includes a negative active material.
  • the negative electrode active material includes, but is not limited to: lithium metal, structured lithium metal, natural graphite, artificial graphite, mesophase carbon microspheres (MCMB), hard carbon, soft carbon, silicon, silicon-carbon Composite, Li-Sn alloy, Li-Sn-O alloy, Sn, SnO, SnO 2 , spinel structure lithiated TiO 2 -Li 4 Ti 5 O 12 , Li-Al alloy, or any combination thereof.
  • the negative electrode active material layer can be formed using a method such as an evaporation method, a sputtering method, or a plating method.
  • the negative electrode includes lithium metal, for example, a conductive skeleton having a spherical twisted shape and metal particles dispersed in the conductive skeleton are used to form the negative active material layer.
  • the spherical stranded conductive skeleton may have a porosity of about 5% to about 85%.
  • a protective layer may be further provided on the lithium metal negative electrode active material layer.
  • the negative active material layer may include a binder, and optionally a conductive material.
  • the binder improves the bonding of the negative active material particles with each other and the bonding of the negative active material with the current collector.
  • the binder includes, but is not limited to: polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyfluoro Ethylene, ethylene oxide-containing polymers, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene butadiene rubber, acrylic (ester) styrene butadiene Rubber, epoxy resin, nylon, etc.
  • conductive materials include, but are not limited to: carbon-based materials, metal-based materials, conductive polymers, or mixtures thereof.
  • the carbon-based material is selected from natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, or any combination thereof.
  • the metal-based material is selected from metal powder, metal fiber, copper, nickel, aluminum, silver.
  • the conductive polymer is a polyphenylene derivative.
  • the current collector includes, but is not limited to: copper foil, nickel foil, stainless steel foil, titanium foil, foamed nickel, foamed copper, conductive metal-coated polymer substrates, and any combination thereof.
  • the negative electrode can be prepared by a preparation method known in the art.
  • the negative electrode can be obtained by mixing an active material, a conductive material, and a binder in a solvent to prepare an active material composition, and coating the active material composition on a current collector.
  • the solvent may include water and the like, but is not limited thereto.
  • the electrochemical device of the present application is provided with a separator between the positive electrode and the negative electrode to prevent short circuits.
  • the material and shape of the isolation membrane used in the electrochemical device of the present application are not particularly limited, and it may be any technology disclosed in the prior art.
  • the isolation membrane includes a polymer or an inorganic substance formed of a material that is stable to the electrolyte of the present application.
  • the isolation film may include a substrate layer and a surface treatment layer.
  • the substrate layer is a non-woven fabric, film or composite film with a porous structure, and the material of the substrate layer is selected from at least one of polyethylene, polypropylene, polyethylene terephthalate and polyimide.
  • a polypropylene porous film, a polyethylene porous film, a polypropylene non-woven fabric, a polyethylene non-woven fabric, or a polypropylene-polyethylene-polypropylene porous composite film can be selected.
  • the substrate layer can be one layer or multiple layers. When the substrate layer is multiple layers, the polymer composition of different substrate layers can be the same or different. The weight average molecular weight of the polymer of different substrate layers is different. It is exactly the same; when the substrate layer is a multilayer, the closed cell temperature of the polymer of different substrate layers is different.
  • At least one surface of the substrate layer is provided with a surface treatment layer
  • the surface treatment layer may be a polymer layer or an inorganic substance layer, or a layer formed by a mixed polymer and an inorganic substance.
  • the inorganic layer includes inorganic particles and a binder.
  • the inorganic particles are selected from alumina, silica, magnesium oxide, titanium oxide, hafnium dioxide, tin oxide, ceria, nickel oxide, zinc oxide, calcium oxide, zirconium oxide, One or a combination of yttrium oxide, silicon carbide, boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, and barium sulfate.
  • the binder is selected from polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyvinyl ether, One or a combination of polymethyl methacrylate, polytetrafluoroethylene and polyhexafluoropropylene.
  • the polymer layer contains a polymer, and the material of the polymer includes polyamide, polyacrylonitrile, acrylate polymer, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyvinyl ether, polyvinylidene fluoride or poly( At least one of vinylidene fluoride-hexafluoropropylene).
  • the electrolytic solution according to the present application can improve the high-temperature storage and cycle performance of the electrochemical device, so that the electrochemical device manufactured thereby is suitable for electronic equipment in various fields.
  • the electrochemical device of the present application is not particularly limited, and it can be used for any purpose known in the prior art.
  • the electrochemical device of the present application can be used in, but not limited to, notebook computers, pen-input computers, mobile computers, e-book players, portable phones, portable fax machines, portable copiers, portable printers, and headsets.
  • the artificial graphite, conductive agent (Super The conductive carbon), sodium carboxymethyl cellulose (CMC), and styrene butadiene rubber (SBR) are mixed according to the weight ratio of 96.4:1.5:0.5:1.6, and deionized water is added to obtain the negative electrode slurry under the action of a vacuum mixer.
  • the solid content of the negative electrode slurry is 54wt%; the negative electrode slurry is evenly coated on the negative electrode current collector copper foil, the copper foil is dried at 85°C, and then after cold pressing, cutting, and slitting, the temperature is 120°C It was dried for 12 hours under vacuum conditions to obtain a negative electrode.
  • a polyethylene (PE) isolation film with a thickness of 12 microns is selected.
  • the electrode assembly is obtained after winding and welding the tabs.
  • the electrode assembly is placed in a packaging bag and dried. Injecting the prepared electrolyte, vacuum packaging, standing, forming (charging to 3.3V with a constant current of 0.02C, and then charging to 3.6V with a constant current of 0.1C), shaping, and capacity testing to obtain a lithium-ion battery.
  • the lithium-ion battery that has reached a constant temperature is charged at a constant current of 0.5C to a voltage of 4.2V, then charged at a constant voltage of 4.2V to a current of 0.05C, and then discharged at a constant current of 1C to a voltage of 3.0V.
  • This is a charge-discharge cycle . Taking the capacity of the first discharge as 100%, the charge-discharge cycle was repeated for 500 weeks, the test was stopped, and the cycle capacity retention rate was recorded as an index for evaluating the cycle performance of the lithium ion battery.
  • the cycle capacity retention rate refers to the capacity when the cycle reaches a certain cycle divided by the capacity at the first discharge multiplied by 100%.
  • Thickness expansion ratio (battery thickness after cycling-battery thickness before cycling)/battery thickness before cycling ⁇ 100%
  • Example 1 to Example 13 and Comparative Example 1 to Comparative Example 7 It can be seen from the data of Example 1 to Example 13 and Comparative Example 1 to Comparative Example 7 that the addition of a specific ratio of silicate compound and fluoroethylene carbonate (FEC) can effectively improve the rate discharge performance and cycle capacity of the battery The retention rate is improved while improving the battery thickness increase during the cycle.
  • FEC fluoroethylene carbonate
  • the above performance improvement can be attributed to the absorption of trace amounts of water and HF in the electrolyte by the silicate compounds, which is beneficial to increase the stability of the electrolyte; at the same time, it is easy to oxidize and form a dense protective film on the positive electrode.
  • the reduction potential of fluoroethylene carbonate (FEC) is higher, and the film is preferentially reduced to the negative electrode during the first charge and discharge.
  • the film is dense and inhibits the decomposition reaction of the electrolyte in the negative electrode.
  • Example 14 Prepare the electrolytes and lithium ion batteries of Example 14 to Example 24 and Comparative Example 8 to Comparative Example 9 according to the above method. Test the rate discharge performance of the lithium ion battery at 25°C, the cycle retention rate at 25°C, the cycle retention rate at 45°C, and the thickness expansion rate. Please see Table 2 for the test results.
  • a disulfonate compound such as : At least one of methylene disulfonate (MMDS) or cyclic carboxylic anhydride (such as maleic anhydride, glutaric anhydride, succinic anhydride, etc.), which can further improve battery cycle performance, gas production and rate discharge performance.
  • MMDS methylene disulfonate
  • cyclic carboxylic anhydride such as maleic anhydride, glutaric anhydride, succinic anhydride, etc.
  • Example 25 Prepare the electrolytes of Example 25 to Example 34 and the lithium ion battery according to the above method. Test the rate discharge performance of the lithium ion battery at 25°C, the cycle retention rate at 25°C, the cycle retention rate at 45°C, and the thickness expansion rate. Please see Table 3 for the test results.
  • Example 27 to Example 33 and Example 19 it can be seen from Example 27 to Example 33 and Example 19 that in the electrolyte containing tetraethyl silicate, FEC and maleic anhydride, 0.1% to about 13% of other additives (such as 1,3- At least one of propane sultone (PS), vinylene carbonate (VC), LiPO 2 F 2 or 1,3,6-hexane trinitrile), which can further improve battery cycleability, gas production and Rate discharge performance.
  • PS propane sultone
  • VC vinylene carbonate
  • LiPO 2 F 2 or 1,3,6-hexane trinitrile 1,3- At least one of propane sultone (PS), vinylene carbonate (VC), LiPO 2 F 2 or 1,3,6-hexane trinitrile
  • a specific amount of other electrolyte is added to the electrolyte containing a specific amount of tetraethyl silicate and FEC.
  • Additives for example, at least one of 1,3-propane sultone (PS), vinylene carbonate (VC), LiPO 2 F 2 , 1,3,6-hexane trinitrile or succinonitrile (SN) ), which can further improve the battery's normal temperature cycle and high temperature cycle performance.
  • PS 1,3-propane sultone
  • VC vinylene carbonate
  • LiPO 2 F 2 1,3,6-hexane trinitrile or succinonitrile
  • SN succinonitrile
  • references to “some embodiments”, “partial embodiments”, “one embodiment”, “another example”, “examples”, “specific examples” or “partial examples” throughout the specification mean At least one embodiment or example in this application includes the specific feature, structure, material, or characteristic described in the embodiment or example. Therefore, descriptions appearing in various places throughout the specification, such as: “in some embodiments”, “in embodiments”, “in one embodiment”, “in another example”, “in an example “In”, “in a specific example” or “exemplified”, which are not necessarily quoting the same embodiment or example in this application.
  • the specific features, structures, materials or characteristics herein can be combined in one or more embodiments or examples in any suitable manner.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Inorganic Chemistry (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Physics & Mathematics (AREA)
  • Materials Engineering (AREA)
  • Secondary Cells (AREA)
  • Electric Double-Layer Capacitors Or The Like (AREA)
  • Primary Cells (AREA)

Abstract

一种电解液及包含所述电解液的电化学装置及电子装置。所述电解液包括氟代碳酸乙烯酯和硅酸酯化合物；并任选进一步包括环状羧酸酐化合物或二磺酸酯化合物中的至少一种。所述电解液任选进一步包括如下其它添加剂：不饱和环状碳酸酯、环状磺酸内酯、环状硫酸内酯和腈化合物中的至少一种。该电解液能显著改善电池循环寿命和倍率放电性能。

Description

一种电解液及电化学装置
优先权申请
本申请要求2019年12月20日提交的申请号为CN201911327801.8的中国申请案的优先权，其内容以全文引用的方式并入本文中。
技术领域
本申请涉及储能技术领域，尤其涉及电解液、包括所述电解液的电化学装置及包括所述电化学装置的电子装置。
背景技术
锂离子电池是上个世纪九十年代发展起来的新一代绿色环保电池，其具有工作电压高、比能量大、循环寿命长、环境友好、无记忆效应等优点，被广泛应用于新能源电动汽车、3C电子产品、便携式电子设备、电动工具、储能、军工、航空航天等领域。然而，随着锂离子电池应用的不断拓展及现代信息技术的持续发展，人们对锂离子电池的电池能量密度及安全性能有了更高的要求。
开发高电压型锂离子电池是提高锂离子电池能量密度的有效手段之一。在高电压和高温条件下，正极材料的氧化活性升高、稳定性下降，传统的电解液在正极表面氧化分解加快，产生气体。同时，正极活性材料(特别是锰基材料)中的过渡金属元素(如镍、钴、锰等)会加速溶出，经过充放电过程后在负极沉积，从而破坏固体电解质膜(SEI)，造成电解液在负极的还原分解，引起锂离子电池电化学性能进一步恶化。如何进一步提升锂离子电池的高温存储及循环性能已经成为本领域亟待解决的问题。
发明内容
本申请提供一种电解液、包含所述电解液的电化学装置及包含所述电化学装置的电子装置，其中所述电解液中包含氟代碳酸乙烯酯和硅酸酯化合物。将特定比例的氟代碳酸乙烯酯和硅酸酯化合物加入电解液中，有利于在正负极表面形成稳定的 界面保护层，从而显著改善锂离子电池的循环寿命和高温存储性能。
在一些实施例中，本申请提供了一种电解液，其包括氟代碳酸乙烯酯和硅酸酯化合物。
在一些实施例中，在所述电解液中，所述硅酸酯化合物的结构如式I所示：
Figure PCTCN2020080596-appb-000001
其中，R 1、R 2、R 3和R 4各自独立地选自取代或未取代的C 1～C 10烃基，其中经取代时，取代基为卤素，其中所述硅酸酯化合物与所述氟代碳酸乙烯酯的质量比为1:1至1:10。
在一些实施例中，在所述电解液中，所述硅酸酯化合物包含：
Figure PCTCN2020080596-appb-000002
中的至少一种。
在一些实施例中，在所述电解液中，所述硅酸酯化合物的含量为所述电解液总重量的约0.1重量％至约5重量％。
在一些实施例中，所述电解液中进一步包含环状羧酸酐化合物，其中所述环状羧酸酐化合物具有式II、式III或式IV结构中的至少一种：
Figure PCTCN2020080596-appb-000003
其中R 5、R 6、R 7、R 8、R 9、R 10和R 11各自独立选自：氢、卤素和取代或未取代的C 1～C 10烃基，其中经取代时，取代基为卤素。
在一些实施例中，在所述电解液中，所述环状羧酸酐的含量为所述电解液总重量的约0.1重量％至约5重量％。
在一些实施例中，在所述电解液中，所述环状羧酸酐包含马来酸酐、丁二酸酐、2-甲基琥珀酸酐、2,3-二甲基琥珀酸酐或戊二酸酐中的至少一种。
在一些实施例中，在所述电解液中，其进一步包含具有式V的二磺酸酯化合物:
Figure PCTCN2020080596-appb-000004
中n为1至4的整数。
在一些实施例中，在所述电解液中，所述二磺酸酯化合物的含量为所述电解液总重量的约0.1重量％至约5重量％。
在一些实施例中，所述二磺酸酯化合物选自甲烷二磺酸亚甲酯。
在一些实施例中，在所述电解液中进一步包含下述添加剂：LiPO 2F 2、不饱和环状碳酸酯、环状磺酸内酯、环状硫酸内酯或腈化合物中的至少一种。所述添加剂的含量为所述电解液总重量的约0.001重量％至约13重量％；其中，
所述LiPO 2F 2的含量为所述电解液总重量的约0.001重量％至约2重量％；
所述不饱和环状碳酸酯包括碳酸亚乙烯酯或乙烯基碳酸乙烯酯中的至少一种，所述不饱和环状碳酸酯的含量为所述电解液总重量的约0.001重量％至约2重量％；
所述环状磺酸内酯包括1,3-丙烷磺酸内酯、1,4-丁烷磺酸内酯或1,3-丙烯磺酸内酯中的至少一种，所述环状磺酸内酯的含量为所述电解液总重量的约0.01重量％至约3重量％；
所述环状硫酸内酯包括硫酸乙烯酯、硫酸丙烯酯或4-甲基硫酸亚乙酯中的至少一种；所述环状硫酸内酯的含量为所述电解液总重量的0.01重量％至3重量％，且
所述腈化合物包括丁二腈、戊二腈、己二腈、2-亚甲基戊二腈、二丙基丙二腈、1,3,6-已烷三腈、1,2,6-已烷三腈、1,3,5-戊烷三腈或1,2-双(氰乙氧基)乙烷中的至少一种，所述腈化合物的含量为所述电解液总重量的约0.5重量％至约7重量％。
在一些实施例中，本申请提供了一种电化学装置，其包括上述任一种电解液。
在一些实施例中，本申请提供了一种电子装置，其包括上述电化学装置。
本申请实施例的额外层面及优点将部分地在后续说明中描述、显示、或是经由 本申请实施例的实施而阐释。
具体实施方式
本申请的实施例将会被详细的描示在下文中。本申请的实施例不应该被解释为对本申请的限制。
如本文中所使用，术语“大致”、“大体上”、“实质”及“约”用以描述及说明小的变化。当与事件或情形结合使用时，所述术语可指代其中事件或情形精确发生的例子以及其中事件或情形极近似地发生的例子。举例来说，当结合数值使用时，所述术语可指代小于或等于所述数值的±10％的变化范围，例如小于或等于±5％、小于或等于±4％、小于或等于±3％、小于或等于±2％、小于或等于±1％、小于或等于±0.5％、小于或等于±0.1％、或小于或等于±0.05％。举例来说，如果两个数值之间的差值小于或等于所述值的平均值的±10％(例如小于或等于±5％、小于或等于±4％、小于或等于±3％、小于或等于±2％、小于或等于±1％、小于或等于±0.5％、小于或等于±0.1％、或小于或等于±0.05％)，那么可认为所述两个数值“大体上”相同。
另外，有时在本文中以范围格式呈现量、比率和其它数值。应理解，此类范围格式是用于便利及简洁起见，且应灵活地理解，不仅包含明确地指定为范围限制的数值，而且包含涵盖于所述范围内的所有个别数值或子范围，如同明确地指定每一数值及子范围一般。
在具体实施方式及权利要求书中，由术语“中的至少一者”、“中的至少一个”、“中的至少一种”或其它相似术语所连接的项目的列表可意味着所列项目的任何组合。例如，如果列出项目A及B，那么短语“A和B中的至少一者”及“A或B中的至少一者”意味着仅A；仅B；或A及B。在另一实例中，如果列出项目A、B及C，那么短语“A、B及C中的至少一者”及“A、B或C中的至少一者”意味着仅A；或仅B；仅C；A及B(排除C)；A及C(排除B)；B及C(排除A)；或A、B及C的全部。项目A可包含单个组分或多个组分。项目B可包含单个组分或多个组分。项目C可包含单个组分或多个组分。
如本文所用，术语“烃基”涵盖烷基、烯基、炔基。例如，烃基预期是具有1至10个碳原子的直链烃结构。“烃基”还预期是具有3至10个碳原子的支链或环 状烃结构。当指定具有具体碳数的烃基时，预期涵盖具有该碳数的所有几何异构体。本文中烃基还可以为1至8个碳原子的烃基、1至6个碳原子的烃基、1至4个碳原子的烃基。另外，烃基可以是任选地被取代的。例如，烃基可被包括氟、氯、溴和碘在内的卤素或烷基取代。
术语“烷基”预期是具有1至10个碳原子的直链饱和烃结构。“烷基”还预期是具有3至10个碳原子的支链或环状烃结构。例如，烷基可为1至8个碳原子的烷基、1至6个碳原子的烷基、1至4个碳原子的烷基。当指定具有具体碳数的烷基时，预期涵盖具有该碳数的所有几何异构体。因此，例如，“丁基”意思是包括正丁基、仲丁基、异丁基、叔丁基和环丁基；“丙基”包括正丙基、异丙基和环丙基。烷基实例包括，但不限于甲基、乙基、正丙基、异丙基、环丙基、正丁基、异丁基、仲丁基、叔丁基、环丁基、正戊基、异戊基、新戊基、环戊基、甲基环戊基、乙基环戊基、正己基、异己基、环己基、正庚基、辛基、环丙基、环丁基、降冰片基等。另外，烷基可以是任选地被取代的。
术语“烯基”是指可为直链或具支链且具有至少一个且通常1个、2个或3个碳碳双键的单价不饱和烃基团。除非另有定义，否则所述烯基通常含有2至10个碳原子，例如可以为6至10个碳原子的烯基、2至8个碳原子的烯基或2至6个碳原子的烯基。代表性烯基包括(例如)乙烯基、正丙烯基、异丙烯基、正-丁-2-烯基、丁-3-烯基、正-己-3-烯基等。另外，烯基可以是任选地被取代的。
术语“炔基”是指可为直链或具支链且具有至少一个且通常具有1个、2个或3个碳碳三键的单价不饱和烃基团。除非另有定义，否则所述炔基通常含有2个至10个碳原子，例如可以为6至10个碳原子的炔基、2至8个碳原子的炔基或2至6个碳原子的炔基。代表性炔基包括(例如)乙炔基、丙-2-炔基(正-丙炔基)、正-丁-2-炔基、正-己-3-炔基等。另外，炔基可以是任选地被取代的。
如本文所用，术语“卤素”可为F、Cl、Br或I。
一、电解液
本申请提供了一种电解液，所述电解液中包含氟代碳酸乙烯酯(FEC)和硅酸酯化合物。
在一些实施例中，所述硅酸酯化合物的结构如式I所示：
Figure PCTCN2020080596-appb-000005
其中，R 1、R 2、R 3和R 4各自独立地选自取代或未取代的C 1～C 10烃基、取代或未取代的C 1～C 6烃基、或取代或未取代的C 1～C 4烃基，其中经取代时，取代基为卤素。在一些实施例中，R 1、R 2、R 3和R 4各自独立地选自取代或未取代的C 1～C 4烷基，其中经取代时，取代基为卤素。在又一些实施例中，R 1、R 2、R 3和R 4各自独立地选自甲基、乙基或丙基。
在一些实施例中，在所述电解液中，所述式I的硅酸酯化合物选自如下化合物1至3中的至少一种：
Figure PCTCN2020080596-appb-000006
在一些实施例中，所述式I的硅酸酯化合物为硅酸四乙酯(化合物1)。
在一些实施例中，所述硅酸酯化合物与所述氟代碳酸乙烯酯(FEC)的质量比为约1:1至约1:10。在一些实施例中，所述硅酸酯化合物与所述氟代碳酸乙烯酯(FEC)的质量比为或约1:2至约1:6，在一些实施例中，所述硅酸酯化合物与所述氟代碳酸乙烯酯(FEC)的质量比为约1:3至约1:5。在一些实施例中，所述质量比为约1:2、约1:3、约1:4、约1:5、约1:6、或约1:7。在电解液中加入硅酸酯化合物和氟代碳酸乙烯酯、且二者处于上述范围能够稳定电解液，同时，在正极表面形成致密的保护层，提高电池的循环性能和倍率性能。
在一些实施例中，所述硅酸酯化合物的含量为所述电解液总重量的约0.1重量％至约5重量％。在一些实施例中，所述硅酸酯化合物的含量为所述电解液总重量的约0.5重量％至约4重量％。在一些实施例中，所述硅酸酯化合物的含量为所述电解液总重量的约1重量％至约3重量％。在一些实施例中，所述硅酸酯化合物的含量为所述电解液总重量的约1.5重量％至约2重量％。在一些实施例中，所述硅酸酯化合物的含量为所述电解液总重量的约0.5重量％、约1重量％、约1.5重量％、约 2重量％、约2.5重量％、约3重量％、约3.5重量％或约4重量％。若含量低于0.1重量％，对电解液的稳定性提高有限，大于5重量％时，正极成膜过厚，影响Li +传输从而恶化电芯阻抗及循环性能。
在一些实施例中，所述电解液中进一步包含环状羧酸酐化合物，其中所述环状羧酸酐化合物具有式II、式III或式IV结构中的至少一种：
Figure PCTCN2020080596-appb-000007
其中R 5、R 6、R 7、R 8、R 9、R 10和R 11各自独立选自：氢、卤素、经取代或未取代的C 1～C 10烃基、经取代或未取代的C 1～C 6烃基、或经取代或未取代的C 1～C 4烃基，其中经取代时，取代基为卤素。在一些实施例中，R 5、R 6、R 7、R 8、R 9、R 10和R 11各自独立地选自取代或未取代的C 1～C 4烷基，其中经取代时，取代基为卤素。在又一些实施例中，R 5、R 6、R 7、R 8、R 9、R 10和R 11各自独立地选自氢或甲基。
在一些实施例中，所述环状羧酸酐包含马来酸酐、丁二酸酐、2-甲基琥珀酸酐、2,3-二甲基琥珀酸酐或戊二酸酐中的至少一种。
在一些实施例中，所述环状羧酸酐的含量占所述电解液总重量的约0.1重量％至约5重量％；在一些实施例中，所述环状羧酸酐的含量占所述电解液总重量的约0.5重量％至约4重量％；在一些实施例中，所述环状羧酸酐的含量占所述电解液总重量的约1重量％至约3重量％；在一些实施例中，所述环状羧酸酐的含量占所述电解液总重量的约1.5重量％至约2重量％；在一些实施例中，所述环状羧酸酐占所述电解液总重量的约0.5重量％、约1重量％、约1.5重量％、约2重量％、约2.5重量％、约3重量％、约3.5重量％或约4重量％。当所述环状羧酸酐加入上述电解液中，由于环状羧酸酐较高的还原电位，可以进一步优先在负极还原成致密的SEI膜，进一步修饰了硅酸酯化合物与FEC所形成的SEI，使Li +易于穿梭，进一步改善了电池的倍率及循环性能。所述环状羧酸酐的含量太低，不足以在负极界面形成稳定的保护，达不到改善循环性能效果；当所述环状羧酸酐的含量太高，会导致成膜厚度过大，从而导致电池容量衰减和电池阻抗增加。
在一些实施例中，在所述电解液中，其进一步包含具有式V的二磺酸酯化合物:
Figure PCTCN2020080596-appb-000008
其中n为1至4的整数。
在一些实施例中，所述二磺酸酯化合物选自甲烷二磺酸亚甲酯(MMDS)。
在一些实施例中，所述二磺酸酯化合物的含量占所述电解液总重量的约0.1重量％至约5重量％；在一些实施例中，所述二磺酸酯化合物的含量占所述电解液总重量的约0.5重量％至约4重量％；在一些实施例中，所述二磺酸酯化合物的含量占所述电解液总重量的约1重量％至约3重量％；在一些实施例中，所述二磺酸酯化合物的含量占所述电解液总重量的约1.5重量％至约2重量％；在一些实施例中，所述二磺酸酯化合物占所述电解液总重量的约0.5重量％、约1重量％、约1.5重量％、约2重量％、约2.5重量％、约3重量％、约3.5重量％或约4重量％。所述二磺酸酯加入上述电解液中，可以在正极形成稳定性优异的SEI膜，进一步抑制了正极材料中过渡金属的溶出及降低了与电解液的直接接触，从而进一步改善电池的倍率性能及循环性能。
在一些实施例中，在所述电解液中进一步包含下述添加剂：不饱和环状碳酸酯、环状磺酸内酯、环状硫酸内酯，腈化合物或LiPO 2F 2中的至少一种。在一些实施例中，所述不饱和环状碳酸酯包括碳酸亚乙烯酯(VC)或乙烯基碳酸乙烯酯(VEC)中的至少一种；所述环状磺酸内酯包括1,3-丙烷磺酸内酯(PS)、1,4-丁烷磺酸内酯(BS)或1,3-丙烯磺酸内酯(PST)中的至少一种；所述环状硫酸内酯包括硫酸乙烯酯(DTD)、硫酸丙烯酯或4-甲基硫酸亚乙酯中的至少一种；且所述腈化合物包括丁二腈(SN)、戊二腈、己二腈、2-亚甲基戊二腈、二丙基丙二腈、1,3,6-已烷三腈、1,2,6-已烷三腈、1,3,5-戊烷三腈或1,2-双(氰乙氧基)乙烷中的至少一种。
在一些实施例中，所述添加剂的含量占所述电解液总重量的约0.1重量％至约13重量％；在一些实施例中，所述添加剂的含量占所述电解液总重量的约0.5重量％至约10重量％；在一些实施例中，所述添加剂的含量占所述电解液总重量的约0.5重量％至约8重量％；在一些实施例中，所述添加剂的含量占所述电解液总重量的约1重量％至约7重量％；在一些实施例中，所述添加剂的含量占所述电解液总重量的约1.5重量％至约6重量％；在一些实施例中，所述添加剂占所述电解液总重量的约0.5重量％、约1重量％、约1.5重量％、约2重量％、约2.5重量％、约3重量 ％、约3.5重量％、约4重量％、约4.5重量％、约5重量％、约5.5重量％、约6重量％、约6.5重量％、约7重量％、约7.5重量％、约8重量％、约8.5重量％、约9重量％或约9.5重量％。
在一些实施例中，所述LiPO 2F 2的含量为所述电解液总重量的约0.1重量％至约2重量％；在一些实施例中，所述LiPO 2F 2的含量为所述电解液总重量的约0.1重量％至约1重量％；在一些实施例中，所述LiPO 2F 2的含量为所述电解液总重量的约0.1重量％至约0.6重量％。
在一些实施例中，所述不饱和环状碳酸酯的含量为所述电解液总重量的约0.01重量％至约2重量％；在一些实施例中，所述不饱和环状碳酸酯的含量为所述电解液总重量的约0.01重量％至约1.5重量％；在一些实施例中，所述不饱和环状碳酸酯的含量为所述电解液总重量的约0.01重量％至约1重量％。
在一些实施例中，所述环状磺酸内酯的含量为所述电解液总重量的约0.01重量％至约3重量％；在一些实施例中，所述环状磺酸内酯的含量为所述电解液总重量的约0.1重量％至约2重量％；在一些实施例中，所述环状磺酸内酯的含量为所述电解液总重量的约0.5重量％至约1.5重量％；
在一些实施例中，所述环状硫酸内酯的含量为所述电解液总重量的约0.01重量％至约3重量％；在一些实施例中，所述环状硫酸内酯的含量为所述电解液总重量的约0.1重量％至约2重量％；在一些实施例中，所述环状硫酸内酯的含量为所述电解液总重量的约0.5重量％至约1.5重量％。
在一些实施例中，所述腈化合物的含量为所述电解液总重量的约0.5重量％至约7重量％；在一些实施例中，所述腈化合物的含量为所述电解液总重量的约0.5重量％至约5重量％；在一些实施例中，所述腈化合物的含量为所述电解液总重量的约0.5重量％至约3重量％；在一些实施例中，所述腈化合物的含量为所述电解液总重量的约1重量％至约2重量％。
在一些实施例中，所述的电解液其进一步包括有机溶剂和锂盐。
在一些实施例中，所述有机溶剂包含环状酯和链状酯，环状酯和链状酯的质量比为约1:9至约7:3，所述环状酯选自碳酸乙烯酯(EC)、碳酸丙烯酯(PC)、γ-丁内酯(BL)、含氟基团取代的碳酸乙烯酯或碳酸丙烯酯中的至少一种；所述链状 酯选自碳酸二甲酯(DMC)、碳酸二乙酯(DEC)、碳酸甲乙酯(EMC)、乙酸乙酯(EA)、甲酸甲酯(MF)、甲酸乙酯(MA)、丙酸乙酯(EP)、丙酸丙酯(PP)、丁酸甲酯(MB)、氟代碳酸甲乙酯、氟代丙酸乙酯等中的至少一种。在一些实施例中，所述有机溶剂的含量为所述电解液总重量的约60重量％至约95重量％；在一些实施例中，所述有机溶剂的含量为所述电解液总重量的约60重量％至约90重量％。在一些实施例中，所述有机溶剂的含量为所述电解液总重量的约70重量％至约85重量％。
在一些实施例中，所述锂盐为有机锂盐或无机锂盐中的至少一种。在一些实施例中，所述锂盐中含有氟元素、硼元素、磷元素中的至少一种。在一些实施例中，所述锂盐选自六氟磷酸锂(LiPF 6)、二氟磷酸锂、双三氟甲烷磺酰亚胺锂LiN(CF 3SO 2) 2、双(氟磺酰)亚胺锂Li(N(SO 2F) 2、双草酸硼酸锂LiB(C 2O 4) 2、二氟草酸硼酸锂LiBF 2(C 2O 4)、六氟砷酸锂(LiAsF 6)、高氯酸锂(LiClO 4)、三氟甲磺酸锂(LiCF 3SO 3)中的至少一种。在一些实施例中，锂盐可以是六氟磷酸锂。在一些实施例中，所述锂盐的浓度为约0.5mol/L至约1.8mol/L。在一些实施例中，所述锂盐的浓度为约0.8mol/L至约1.5mol/L。在一些实施例中，所述锂盐的浓度为约0.8mol/L至约1mol/L。
二、电化学装置
本申请的电化学装置可以包括发生电化学反应的任何装置，它的具体实例包括所有种类的一次电池、二次电池、燃料电池、太阳能电池或电容器。特别地，该电化学装置是锂二次电池，包括锂金属二次电池、锂离子二次电池、锂聚合物二次电池或锂离子聚合物二次电池。在一些实施例中，本申请的电化学装置包括具有能够吸留、放出金属离子的正极活性物质的正极；具有能够吸留、放出金属离子的负极活性物质的负极；置于正极和负极之间的隔离膜；以及本申请的电解液。
电解液
本申请的电化学装置中使用的电解液为本申请的上述任何电解液。此外，本申请的电化学装置中使用的电解液还可包含不脱离本申请的主旨的范围内的其它电解液。
正极
本申请的电化学装置中使用的正极的材料可以使用本领域公知的材料、构造和制造方法制备。在一些实施例中，可以采用US9812739B中记载的技术制备本申请的正极，其以全文引用的方式并入本申请中。
在一些实施例中，正极包括集流体和位于该集流体上的正极活性材料层。正极活性材料包括可逆地嵌入和脱嵌锂离子的至少一种锂化插层化合物。在一些实施例中，正极活性材料包括复合氧化物。在一些实施例中，该复合氧化物含有锂以及从钴、锰和镍中选择的至少一种元素。
在一些实施例中，正极活性材料选自锂镍钴锰(NCM)三元材料、磷酸亚铁锂(LiFePO 4)、LiCoO 2、LiNiO 2、LiMn 2O 4、LiCo 1-yM yO 2、LiNi 1-yM yO 2、LiMn 2-yM yO 4、LiNi xCo yMn zM 1-x-y-zO 2，其中M选自Fe、Co、Ni、Mn、Mg、Cu、Zn、Al、Sn、B、Ga、Cr、Sr、V、Ti中的一种或多种，且0≤y≤1，0≤x≤1，0≤z≤1，x+y+z≤1或它们的任意组合。
在一些实施例中，正极活性材料可以在其表面上具有涂层，或者可以与具有涂层的另一化合物混合。该涂层可以包括从涂覆元素的氧化物、涂覆元素的氢氧化物、涂覆元素的羟基氧化物、涂覆元素的碳酸氧盐和涂覆元素的羟基碳酸盐中选择的至少一种涂覆元素化合物。用于涂层的化合物可以是非晶的或结晶的。
在一些实施例中，在涂层中含有的涂覆元素可以包括Mg、Al、Co、K、Na、Ca、Si、Ti、V、Sn、Ge、Ga、B、As、Zr、P或它们的任意组合。在一些实施例中，涂覆层中的涂覆物可以为AlPO 4、Mg 3(PO 4) 2、Co 3(PO 4) 2、AlF 3、MgF 2、CoF 3、NaF、B 2O 3中的至少一种。在一些实施例中，基于正极活性物质总重量计，涂层中的涂覆元素的含量为约0.01重量％至约10重量％。可以通过任何方法来施加涂层，只要该方法不对正极活性材料的性能产生不利影响即可。例如，该方法可以包括对本领域公知的任何涂覆方法，例如喷涂、浸渍等。
正极活性材料层还包括粘合剂，并且可选地包括导电材料。粘合剂提高正极活性材料颗粒彼此间的结合，并且还提高正极活性材料与集流体的结合。
在一些实施例中，粘合剂包括，但不限于：聚乙烯醇、羟丙基纤维素、二乙酰基纤维素、聚氯乙烯、羧化的聚氯乙烯、聚氟乙烯、含亚乙基氧的聚合物、聚乙烯吡咯烷酮、聚氨酯、聚四氟乙烯、聚偏1,1-二氟乙烯、聚乙烯、聚丙烯、丁苯橡胶、 丙烯酸(酯)化的丁苯橡胶、环氧树脂、尼龙等。
在一些实施例中，导电材料包括，但不限于：基于碳的材料、基于金属的材料、导电聚合物和它们的混合物。在一些实施例中，基于碳的材料选自天然石墨、人造石墨、碳黑、乙炔黑、科琴黑、碳纤维、碳纳米管、石墨烯或其任意组合。在一些实施例中，基于金属的材料选自金属粉、金属纤维、铜、镍、铝、银。在一些实施例中，导电聚合物为聚亚苯基衍生物。
在一些实施例中，集流体可以是铝，但不限于此。
正极可以通过本领域公知的制备方法制备。例如，正极可以通过如下方法获得：在溶剂中将活性材料、导电材料和粘合剂混合，以制备活性材料组合物，并将该活性材料组合物涂覆在集流体上。在一些实施例中，溶剂可以包括N-甲基吡咯烷酮等，但不限于此。
在一些实施例中，正极通过在集流体上使用包括锂过渡金属系化合物粉体和粘结剂的正极活性物质层形成正极材料而制成。
在一些实施例中，正极活性物质层通常可以通过如下操作来制作：将正极材料和粘结剂(根据需要而使用的导电材料和增稠剂等)进行干式混合而制成片状，将得到的片压接于正极集流体，或者使这些材料溶解或分散于液体介质中而制成浆料状，涂布在正极集流体上并进行干燥。在一些实施例中，正极活性物质层的材料包括任何本领域公知的材料。
负极
本申请的电化学装置中使用的负极的材料、构成和其制造方法可包括任何现有技术中公开的技术。在一些实施例中，负极为美国专利申请US9812739B中记载的负极，其以全文引用的方式并入本申请中。
在一些实施例中，负极包括集流体和位于该集流体上的负极活性材料层。负极活性材料包括可逆地嵌入/脱嵌锂离子的材料。在一些实施例中，可逆地嵌入/脱嵌锂离子的材料包括碳材料。在一些实施例中，碳材料可以是在锂离子可充电电池中通常使用的任何基于碳的负极活性材料。在一些实施例中，碳材料包括，但不限于：结晶碳、非晶碳或它们的混合物。结晶碳可以是无定形的、片形的、小片形的、球形的或纤维状的天然石墨或人造石墨。非晶碳可以是软碳、硬碳、中间相沥青碳化 物、煅烧焦等。
在一些实施例中，负极活性材料层包括负极活性材料。在一些实施例中，负极活性材料包括，但不限于：锂金属、结构化的锂金属、天然石墨、人造石墨、中间相微碳球(MCMB)、硬碳、软碳、硅、硅-碳复合物、Li-Sn合金、Li-Sn-O合金、Sn、SnO、SnO 2、尖晶石结构的锂化TiO 2-Li 4Ti 5O 12、Li-Al合金或其任意组合。
当负极包括硅碳化合物时，基于负极活性材料总重量，硅：碳＝约1:10～10:1，硅碳化合物的中值粒径D50为约0.1微米至20微米。当负极包括合金材料时，可使用蒸镀法、溅射法、镀敷法等方法形成负极活性物质层。当负极包括锂金属时，例如用具有球形绞状的导电骨架和分散在导电骨架中的金属颗粒形成负极活性物质层。在一些实施例中，球形绞状的导电骨架可具有约5％至约85％的孔隙率。在一些实施例中，锂金属负极活性物质层上还可设置保护层。
在一些实施例中，负极活性材料层可以包括粘合剂，并且可选地包括导电材料。粘合剂提高负极活性材料颗粒彼此间的结合和负极活性材料与集流体的结合。在一些实施例中，粘合剂包括，但不限于：聚乙烯醇、羧甲基纤维素、羟丙基纤维素、二乙酰基纤维素、聚氯乙烯、羧化的聚氯乙烯、聚氟乙烯、含亚乙基氧的聚合物、聚乙烯吡咯烷酮、聚氨酯、聚四氟乙烯、聚偏1,1-二氟乙烯、聚乙烯、聚丙烯、丁苯橡胶、丙烯酸(酯)化的丁苯橡胶、环氧树脂、尼龙等。
在一些实施例中，导电材料包括，但不限于：基于碳的材料、基于金属的材料、导电聚合物或它们的混合物。在一些实施例中，基于碳的材料选自天然石墨、人造石墨、碳黑、乙炔黑、科琴黑、碳纤维或其任意组合。在一些实施例中，基于金属的材料选自金属粉、金属纤维、铜、镍、铝、银。在一些实施例中，导电聚合物为聚亚苯基衍生物。
在一些实施例中，集流体包括，但不限于：铜箔、镍箔、不锈钢箔、钛箔、泡沫镍、泡沫铜、覆有导电金属的聚合物基底和它们的任意组合。
负极可以通过本领域公知的制备方法制备。例如，负极可以通过如下方法获得：在溶剂中将活性材料、导电材料和粘合剂混合，以制备活性材料组合物，并将该活性材料组合物涂覆在集流体上。在一些实施例中，溶剂可以包括水等，但不限于此。
隔离膜
在一些实施例中，本申请的电化学装置在正极与负极之间设有隔离膜以防止短路。本申请的电化学装置中使用的隔离膜的材料和形状没有特别限制，其可为任何现有技术中公开的技术。在一些实施例中，隔离膜包括由对本申请的电解液稳定的材料形成的聚合物或无机物等。
例如隔离膜可包括基材层和表面处理层。基材层为具有多孔结构的无纺布、膜或复合膜，基材层的材料选自聚乙烯、聚丙烯、聚对苯二甲酸乙二醇酯和聚酰亚胺中的至少一种。具体的，可选用聚丙烯多孔膜、聚乙烯多孔膜、聚丙烯无纺布、聚乙烯无纺布或聚丙烯-聚乙烯-聚丙烯多孔复合膜。基材层可以为一层或多层，当基材层为多层时，不同的基材层的聚合物的组成可以相同，也可以不同，不同的基材层的聚合物的重均分子量不完全相同；当基材层为多层时，不同的基材层的聚合物的闭孔温度不同。
在一些实施例中，基材层的至少一个表面上设置有表面处理层，表面处理层可以是聚合物层或无机物层，也可以是混合聚合物与无机物所形成的层。
无机物层包括无机颗粒和粘结剂，无机颗粒选自氧化铝、氧化硅、氧化镁、氧化钛、二氧化铪、氧化锡、二氧化铈、氧化镍、氧化锌、氧化钙、氧化锆、氧化钇、碳化硅、勃姆石、氢氧化铝、氢氧化镁、氢氧化钙和硫酸钡中的一种或几种的组合。粘结剂选自聚偏氟乙烯、偏氟乙烯-六氟丙烯的共聚物、聚酰胺、聚丙烯腈、聚丙烯酸酯、聚丙烯酸、聚丙烯酸盐、聚乙烯呲咯烷酮、聚乙烯醚、聚甲基丙烯酸甲酯、聚四氟乙烯和聚六氟丙烯中的一种或几种的组合。聚合物层中包含聚合物，聚合物的材料包括聚酰胺、聚丙烯腈、丙烯酸酯聚合物、聚丙烯酸、聚丙烯酸盐、聚乙烯呲咯烷酮、聚乙烯醚、聚偏氟乙烯或聚(偏氟乙烯-六氟丙烯)中的至少一种。
三、应用
根据本申请的电解液能够改善电化学装置的高温存储和循环性能，使得由此制造的电化学装置适用于各种领域的电子设备。
本申请的电化学装置的用途没有特别限定，其可用于现有技术中已知的任何用途。在一个实施例中，本申请的电化学装置可用于，但不限于，笔记本电脑、笔输入型计算机、移动电脑、电子书播放器、便携式电话、便携式传真机、便携式复印机、便携式打印机、头戴式立体声耳机、录像机、液晶电视、手提式清洁器、便携 CD机、迷你光盘、收发机、电子记事本、计算器、存储卡、便携式录音机、收音机、备用电源、电机、汽车、摩托车、助力自行车、自行车、照明器具、玩具、游戏机、钟表、电动工具、闪光灯、照相机、家庭用大型蓄电池和锂离子电容器等。
四、实施例
以下举出实施例和比较例对本申请进一步具体地进行说明，但只要不脱离其主旨，则本申请并不限定于这些实施例。
1.锂离子电池的制备
1)正极制备
将锰酸锂(LiMn 2O 4)、导电剂(Super
Figure PCTCN2020080596-appb-000009
的导电碳)、聚偏二氟乙烯(PVDF)按照重量比96:2:2进行混合，加入N-甲基吡咯烷酮(NMP)，在真空搅拌机作用下搅拌均匀，获得正极浆料，其中正极浆料的固含量为72wt％；将正极浆料均匀涂覆于13微米厚的铝箔上，将铝箔在85℃下烘干，然后经过冷压、裁片、分切后，在85℃的真空条件下干燥4小时，得到正极。
(2)负极制备
将人造石墨、导电剂(Super
Figure PCTCN2020080596-appb-000010
的导电碳)、羧甲基纤维素钠(CMC)、丁苯橡胶(SBR)按照重量比96.4:1.5:0.5:1.6进行混合，加入去离子水，在真空搅拌机作用下获得负极浆料，其中负极浆料的固含量为54wt％；将负极浆料均匀涂覆在负极集流体铜箔上，将铜箔在85℃下烘干，然后经过冷压、裁片、分切后，在120℃的真空条件下干燥12小时，得到负极。
(3)电解液制备
在干燥的氩气气氛手套箱中，将碳酸乙烯酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)按照质量比为EC:EMC:DEC＝3:5:2进行混合，接着加入特定量和种类的添加剂，溶解并充分搅拌后加入锂盐LiPF 6，混合均匀后获得电解液。其中，LiPF 6的浓度为1mol/L。电解液中所用到的添加剂的具体种类以及含量如下表所示，添加剂的含量为基于电解液的总质量计算得到的质量百分数。
(4)隔离膜的制备
选用12微米厚的聚乙烯(PE)隔离膜。
(5)锂离子电池的制备
将正极、隔离膜、负极按顺序叠好，使隔离膜处于正、负极之间起到隔离的作用，然后卷绕、焊接极耳后得到电极组件，将电极组件置于包装袋中，干燥，注入上述制备好的电解液，经过真空封装、静置、化成(0.02C恒流充电到3.3V，再以0.1C恒流充电到3.6V)、整形、容量测试等工序，获得锂离子电池。
2.锂离子电池的性能测试
(1)锂离子电池在25℃的倍率测试
将锂离子电池置于25℃恒温箱中，静置30分钟，使锂离子电池达到恒温。将达到恒温的锂离子电池以0.5C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，分别以0.5C/1C/2C/5C的倍率放电至3.0V，记录不同倍率下放电容量，以0.5C放电容量为100％，计算5C放电容量保持率。
(2)锂离子电池在25℃的循环性能
将锂离子电池置于25℃恒温箱中，静置30分钟，使锂离子电池达到恒温。将达到恒温的锂离子电池以0.5C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，接着以1C恒流放电至电压为3.0V，此为一个充放电循环。以首次放电的容量为100％，反复进行充放电循环500周，停止测试，记录循环容量保持率，作为评价锂离子电池循环性能的指标。
循环容量保持率是指，循环至某一圈时的容量除以第一次放电时的容量乘以百分之百。
(3)锂离子电池在45℃的循环性能
将锂离子电池置于45℃恒温箱中，静置30分钟，使锂离子电池达到恒温。将达到恒温的锂离子电池以0.5C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，接着以1C恒流放电至电压为3.0V，此为一个充放电循环。以首次放电的容量为100％，反复进行充放电循环300周，停止测试，记录循环容量保持率，作为评价锂离子电池循环性能的指标。
(4)电池的厚度膨胀率
测量电池的厚度，按下式计算电池的厚度膨胀率：
厚度膨胀率＝(循环后的电池厚度-循环前的电池厚度)/循环前的电池厚度×100％
A.按照上述方法制备实施例1至13和对比例1至7的电解液以及锂离子电池。并测试锂离子电池在25℃倍率放电性能、25℃的循环保持率和45℃循环保持率及厚度膨胀率，测试结果请见表1。
表1
Figure PCTCN2020080596-appb-000011
Figure PCTCN2020080596-appb-000012
其中“/”表示未添加该物质。
由对比例1至对比例6的测试结果可以看出，当电解液中未加入特定结构的硅酸酯化合物和氟代碳酸乙烯酯(FEC)或者仅加入上述两者之一时，电池倍率放电性能及循环性能较差，厚度膨胀率高。
由实施例1到实施例13与对比例1到对比例7数据可看出，特定比例的硅酸酯化合物及氟代碳酸乙烯酯(FEC)的加入可以有效改善电池的倍率放电性能及循环容量保持率，同时改善循环过程电池厚度增长量。不希望受任何理论限制，上述性能改进可归因于硅酸酯类化合物吸附电解液中的痕量水及HF，有利于增加电解液的稳定性；同时易于氧化并在正极形成致密的保护膜，减少电解液对正极的破坏；氟代碳酸乙烯酯(FEC)还原电位较高，在首次充放电时优先在负极还原成膜，成膜致密，抑制了电解液在负极的分解反应。当电解液中添加的硅酸四乙酯与FEC的比例为特定范围时，能更有效地稳定电解液，并在正负极形成更优异的界面保护。硅酸四乙酯与FEC的比例过高时，成膜阻抗较大，导致电池阻抗增加，从而影响电池性能；比例过低时不足以形成好的界面保护，达不到改善电池循环性能的效果。
B.根据按照上述方法制备实施例14至实施例24及对比例8至对比例9的电解液以及锂离子电池。测试锂离子电池在25℃倍率放电性能、25℃的循环保持率和45℃循环保持率及厚度膨胀率。测试结果请见表2。
表2
Figure PCTCN2020080596-appb-000013
Figure PCTCN2020080596-appb-000014
其中“/”表示未添加该物质。
基于实施例6及实施例14至23、以及上述实施例与对比例8至对比例9的比较可以看出，在含有硅酸四乙酯和的电解液中进一步加入二磺酸酯化合物(例如：甲烷二磺酸亚甲酯MMDS)或环状羧酸酐(例如马来酸酐、戊二酸酐和丁二酸酐等)中的至少一者，能够进一步改善电池的循环性能、产气状况和倍率放电性能。
C.根据上述方法制备实施例25至实施例34的电解液以及锂离子电池。测试锂离子电池在25℃倍率放电性能、25℃的循环保持率和45℃循环保持率及厚度膨胀率。测试结果请见表3。
表3
Figure PCTCN2020080596-appb-000015
Figure PCTCN2020080596-appb-000016
其中“/”表示未添加该物质。
从实施例27至实施例33与实施例19可以看出，在含硅酸四乙酯和FEC及马来酸酐的电解液中再加入0.1％至约13％的其它添加剂(例如1,3-丙烷磺酸内酯(PS)、碳酸亚乙烯酯(VC)、LiPO 2F 2或1,3,6-己烷三腈中的至少一者)，能进一步改善电池循环性、产气状况和倍率放电性能。此外，从实施例6与实施例25和26的比较或从实施例7与实施例34的比较可以看出，在含有特定量的硅酸四乙酯和FEC的电解液中加入特定量的其它添加剂(例如1,3-丙烷磺酸内酯(PS)、碳酸亚乙烯酯(VC)、LiPO 2F 2、1,3,6-己烷三腈或丁二腈(SN)中的至少一者)，能进一步提升电池常温循环和高温循环性能。上述实验结果表明这些添加剂结合使用有利于增强电池正负极界面的保护，因而进一步提升电池性能。
整个说明书中对“一些实施例”、“部分实施例”、“一个实施例”、“另一举例”、“举例”、“具体举例”或“部分举例”的引用，其所代表的意思是在本 申请中的至少一个实施例或举例包含了该实施例或举例中所描述的特定特征、结构、材料或特性。因此，在整个说明书中的各处所出现的描述，例如：“在一些实施例中”、“在实施例中”、“在一个实施例中”、“在另一个举例中”，“在一个举例中”、“在特定举例中”或“举例“，其不必然是引用本申请中的相同的实施例或示例。此外，本文中的特定特征、结构、材料或特性可以以任何合适的方式在一个或多个实施例或举例中结合。
尽管已经演示和描述了说明性实施例，本领域技术人员应该理解上述实施例不能被解释为对本申请的限制，并且可以在不脱离本申请的精神、原理及范围的情况下对实施例进行改变，替代和修改。

Claims (10)

  1. 一种电解液，其包含：
    氟代碳酸乙烯酯，和
    式I结构的硅酸酯化合物,
    Figure PCTCN2020080596-appb-100001
    其中R 1、R 2、R 3和R 4各自独立选自取代或未取代的C 1～C 10烃基，其中经取代时，取代基为卤素，
    其中所述硅酸酯化合物与所述氟代碳酸乙烯酯的质量比为1:1至1:10。
  2. 根据权利要求1所述的电解液，其中所述硅酸酯化合物包含：
    Figure PCTCN2020080596-appb-100002
    中的至少一种。
  3. 根据权利要求1所述的电解液，其中所述硅酸酯化合物的含量为所述电解液总重量的0.1重量％至5重量％。
  4. 根据权利要求1所述的电解液，其进一步包含环状羧酸酐化合物，其中所述环状羧酸酐化合物包含式II结构化合物、式III结构化合物或式IV结构化合物中的至少一种：
    Figure PCTCN2020080596-appb-100003
    其中R 5、R 6、R 7、R 8、R 9、R 10和R 11各自独立选自：氢、卤素和取代或未取代的C 1～C 10烃基，其中经取代时，取代基为卤素。
  5. 根据权利要求4所述的电解液，其中所述环状羧酸酐包含马来酸酐、丁二酸酐、2-甲基琥珀酸酐、2,3-二甲基琥珀酸酐或戊二酸酐中的至少一种，所述环状羧酸酐的含量为所述电解液总重量的0.1重量％至5重量％。
  6. 根据权利要求1所述的电解液，其进一步包含具有式V的二磺酸酯化合物:
    Figure PCTCN2020080596-appb-100004
    其中n为1至4的整数；其中所述二磺酸酯化合物的含量为所述电解液总重量的0.1重量％至5重量％。
  7. 根据权利要求1-6中任一所述的电解液，其进一步包含下述添加剂：LiPO 2F 2、不饱和环状碳酸酯、环状磺酸内酯、环状硫酸内酯或腈化合物中的至少一种；其中所述添加剂的含量为所述电解液总重量的0.1重量％至13重量％。
  8. 根据权利要求7所述的电解液，其中：
    所述LiPO 2F 2的含量为所述电解液总重量的0.001重量％至2重量％；
    所述不饱和环状碳酸酯包括碳酸亚乙烯酯或乙烯基碳酸乙烯酯中的至少一种，所述不饱和环状碳酸酯的含量为所述电解液总重量的0.001重量％至2重量％；
    所述环状磺酸内酯包括1,3-丙烷磺酸内酯、1,4-丁烷磺酸内酯或1,3-丙烯磺酸内酯中的至少一种，所述环状磺酸内酯的含量为所述电解液总重量的0.01重量％至3重量％；
    所述环状硫酸内酯包括硫酸乙烯酯、硫酸丙烯酯或4-甲基硫酸亚乙酯中的至少一种；所述环状硫酸内酯的含量为所述电解液总重量的0.01重量％至3重量％；且
    所述腈化合物包括丁二腈、戊二腈、己二腈、2-亚甲基戊二腈、二丙基丙二腈、1,3,6-已烷三腈、1,2,6-已烷三腈、1,3,5-戊烷三腈或1,2-双(氰乙氧基)乙烷中的至少一种，所述腈化合物的含量为所述电解液总重量的0.5重量％至7重量％。
  9. 一种电化学装置，其包括根据权利要求1-8中任一权利要求所述的电解液。
  10. 一种电子装置，其包括根据权利要求9所述的电化学装置。
PCT/CN2020/080596 2019-12-20 2020-03-23 一种电解液及电化学装置 WO2021120434A1 (zh)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP2020518426A JP7311497B2 (ja) 2019-12-20 2020-03-23 リチウムイオン電池および電子デバイス
KR1020207012674A KR102563223B1 (ko) 2019-12-20 2020-03-23 전해액 및 전기화학 장치

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN201911327801.8A CN110994018B (zh) 2019-12-20 2019-12-20 一种电解液及电化学装置
CN201911327801.8 2019-12-20

Publications (1)

Publication Number Publication Date
WO2021120434A1 true WO2021120434A1 (zh) 2021-06-24

Family

ID=70073648

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2020/080596 WO2021120434A1 (zh) 2019-12-20 2020-03-23 一种电解液及电化学装置

Country Status (4)

Country Link
JP (1) JP7311497B2 (zh)
KR (1) KR102563223B1 (zh)
CN (1) CN110994018B (zh)
WO (1) WO2021120434A1 (zh)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113871720A (zh) * 2021-09-28 2021-12-31 厦门大学 一种高安全性电解液及其制备方法和应用
CN113871720B (zh) * 2021-09-28 2024-05-31 厦门大学 一种高安全性电解液及其制备方法和应用

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112117492A (zh) * 2020-10-16 2020-12-22 江苏师范大学 一种有机酯类电解液添加剂及含该添加剂的电解液及锂金属电池和应用
CN114207903A (zh) * 2021-03-31 2022-03-18 宁德新能源科技有限公司 电解液、电化学装置以及电子装置
CN113161619B (zh) * 2021-04-29 2023-04-11 厦门大学 一种弱极性体系电解液及其应用
KR20220170460A (ko) 2021-06-23 2022-12-30 현대모비스 주식회사 차량용 제동장치
CN114300746A (zh) * 2021-12-15 2022-04-08 惠州锂威新能源科技有限公司 电解液添加剂、电解液及储能器件

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001519589A (ja) * 1997-10-02 2001-10-23 ビーエーエスエフ アクチェンゲゼルシャフト Ｌｉイオン貯蔵セル用の電解質組成物における溶媒としてのエステル
CN103367804A (zh) * 2013-06-27 2013-10-23 深圳新宙邦科技股份有限公司 一种锂离子电池用非水电解液及使用该非水电解液的锂离子电池
CN107221704A (zh) * 2017-06-29 2017-09-29 中国科学院长春应用化学研究所 一种锂二次电池用电解液和锂‑氧气二次电池
CN107293792A (zh) * 2017-08-21 2017-10-24 宁波诺丁汉大学 一种非水电解液及高镍三元正极材料电池
CN108292779A (zh) * 2015-11-30 2018-07-17 日本电气株式会社 锂离子二次电池
CN109053792A (zh) * 2018-07-18 2018-12-21 石家庄圣泰化工有限公司 电池电解液中用的环状硅酸酯化合物及其制备方法
CN109818065A (zh) * 2019-04-01 2019-05-28 北京工商大学 用于锂离子二次电池的含添加剂的高压电解液及制备方法

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001266938A (ja) * 2000-03-15 2001-09-28 Toshiba Corp 非水電解質二次電池
JP2003242991A (ja) * 2002-02-04 2003-08-29 Lithdyne Internatl Inc アルコキシシランを含有する安定化リチウム電気化学的セル
KR100528933B1 (ko) * 2003-10-22 2005-11-15 삼성에스디아이 주식회사 유기전해액 및 이를 채용한 리튬 전지
JP5694833B2 (ja) * 2010-09-22 2015-04-01 富士フイルム株式会社 非水二次電池用電解液及びリチウム二次電池
CN104769765A (zh) * 2012-11-08 2015-07-08 住友化学株式会社 钠二次电池
CN104425841B (zh) * 2013-09-05 2017-10-17 华为技术有限公司 一种非水有机高电压电解液添加剂、非水有机高电压电解液和锂离子二次电池
JP2019057356A (ja) * 2016-02-08 2019-04-11 セントラル硝子株式会社 非水電解液電池用電解液、及びこれを用いた非水電解液電池

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001519589A (ja) * 1997-10-02 2001-10-23 ビーエーエスエフ アクチェンゲゼルシャフト Ｌｉイオン貯蔵セル用の電解質組成物における溶媒としてのエステル
CN103367804A (zh) * 2013-06-27 2013-10-23 深圳新宙邦科技股份有限公司 一种锂离子电池用非水电解液及使用该非水电解液的锂离子电池
CN108292779A (zh) * 2015-11-30 2018-07-17 日本电气株式会社 锂离子二次电池
CN107221704A (zh) * 2017-06-29 2017-09-29 中国科学院长春应用化学研究所 一种锂二次电池用电解液和锂‑氧气二次电池
CN107293792A (zh) * 2017-08-21 2017-10-24 宁波诺丁汉大学 一种非水电解液及高镍三元正极材料电池
CN109053792A (zh) * 2018-07-18 2018-12-21 石家庄圣泰化工有限公司 电池电解液中用的环状硅酸酯化合物及其制备方法
CN109818065A (zh) * 2019-04-01 2019-05-28 北京工商大学 用于锂离子二次电池的含添加剂的高压电解液及制备方法

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113871720A (zh) * 2021-09-28 2021-12-31 厦门大学 一种高安全性电解液及其制备方法和应用
CN113871720B (zh) * 2021-09-28 2024-05-31 厦门大学 一种高安全性电解液及其制备方法和应用

Also Published As

Publication number Publication date
CN110994018B (zh) 2021-04-06
JP7311497B2 (ja) 2023-07-19
JP2022517285A (ja) 2022-03-08
CN110994018A (zh) 2020-04-10
KR102563223B1 (ko) 2023-08-02
KR20210081303A (ko) 2021-07-01

Similar Documents

Publication Publication Date Title
CN109860703B (zh) 一种电解液及电化学装置
CN111082129B (zh) 电化学装置和电子装置
CN110994018B (zh) 一种电解液及电化学装置
CN111430793B (zh) 电解液及使用其的电化学装置和电子装置
CN111342137B (zh) 一种电解液及电化学装置
WO2021189255A1 (zh) 一种电解液及电化学装置
CN111697266B (zh) 电解液和包括其的电化学装置及电子装置
WO2021223181A1 (zh) 一种电解液及电化学装置
US11031630B2 (en) Electrolyte and electrochemical device
WO2021128206A1 (zh) 一种电解液及电化学装置
CN110518286A (zh) 电解液及包括电解液的电化学装置及电子装置
WO2021127993A1 (zh) 电解液以及使用其的电化学装置和电子装置
WO2022089280A1 (zh) 电化学装置及包括其的电子装置
CN111697267A (zh) 电解液和包含电解液的电化学装置及电子装置
JP7311593B2 (ja) 電解液及び電気化学装置
WO2021238531A1 (zh) 一种非水电解液及锂离子电池
WO2021128203A1 (zh) 一种电解液及电化学装置
WO2023078059A1 (zh) 电解液以及使用其的电化学装置和电子装置
CN112055910B (zh) 一种电解液及电化学装置
WO2022087830A1 (zh) 电解液及包括其的电化学装置和电子装置
WO2021196019A1 (zh) 一种电解液及电化学装置
CN112838269A (zh) 电解液及包含其的电化学装置和电子设备
CN116053461B (zh) 电化学装置和包括其的电子装置
CN113889664B (zh) 电解液、电化学装置和电子装置
WO2021195965A1 (zh) 一种电化学装置及包括其的电子装置

Legal Events

Date Code Title Description
ENP Entry into the national phase

Ref document number: 2020518426

Country of ref document: JP

Kind code of ref document: A

121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 20903710

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 20903710

Country of ref document: EP

Kind code of ref document: A1