WO2022204980A1 - 一种电解液及含有该电解液的电化学装置 - Google Patents

一种电解液及含有该电解液的电化学装置 Download PDF

Info

Publication number
WO2022204980A1
WO2022204980A1 PCT/CN2021/084094 CN2021084094W WO2022204980A1 WO 2022204980 A1 WO2022204980 A1 WO 2022204980A1 CN 2021084094 W CN2021084094 W CN 2021084094W WO 2022204980 A1 WO2022204980 A1 WO 2022204980A1
Authority
WO
WIPO (PCT)
Prior art keywords
electrolyte
lithium
compound
content
positive electrode
Prior art date
Application number
PCT/CN2021/084094
Other languages
English (en)
French (fr)
Inventor
刘建禹
栗文强
郑建明
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 CN202180004970.7A priority Critical patent/CN114556662A/zh
Priority to PCT/CN2021/084094 priority patent/WO2022204980A1/zh
Priority to EP21933661.7A priority patent/EP4300651A4/en
Priority to BR112023019937A priority patent/BR112023019937A2/pt
Publication of WO2022204980A1 publication Critical patent/WO2022204980A1/zh
Priority to US18/373,983 priority patent/US20240021878A1/en

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
    • 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
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0568—Liquid materials characterised by the solutes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—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
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H01M4/661—Metal or alloys, e.g. alloy coatings
    • 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
    • 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

  • the present application relates to the field of energy storage, in particular to an electrolyte and an electrochemical device containing the electrolyte.
  • lithium-ion batteries have the characteristics of high energy density, no memory effect and high working voltage, and are gradually replacing traditional Ni-Cd and MH-Ni batteries.
  • people's requirements for the safety performance of lithium-ion batteries continue to increase, and the development of higher-safety lithium-ion batteries is one of the main needs of the market.
  • a first aspect of the present application provides an electrolyte, comprising a fluorine-containing sulfonimide lithium salt and a trinitrile compound, wherein, based on the weight of the electrolyte, the content of the fluorine-containing sulfonimide lithium salt is X %, the content of the trinitrile compound is Y%, which satisfies 1 ⁇ X+Y ⁇ 6.
  • the electrolyte of the invention can improve the safety performance of the lithium ion battery.
  • the electrolyte further includes lithium hexafluorophosphate (LiPF 6 ).
  • LiPF 6 lithium hexafluorophosphate
  • the content of lithium hexafluorophosphate is Z % based on the weight of the electrolyte, wherein X+Z ⁇ 7.5, and X/Z ⁇ 1.
  • the fluorine-containing lithium sulfonimide salt comprises one or both of lithium bisfluorosulfonimide (LiFSI) or lithium bistrifluoromethanesulfonimide (LiTFSI).
  • the electrolyte satisfies at least one of the following conditions (a) or (b): (a) Z is less than 5; (b) 0.8 ⁇ (X+Z)/(X+Y ) ⁇ 3.5.
  • the trinitrile compound includes at least one of a compound of formula II or a compound of formula III:
  • a, d and f are each independently selected from an integer of 1-6, and b, c and e are each independently selected from an integer of 0-6;
  • g, h and i are each independently selected from an integer of 0-6.
  • the trinitrile compound comprises 1,3,5-pentanetricarbonitrile, 1,2,3-propanetricarbonitrile, 1,3,6-hexanetricarbonitrile, 1,2,6 -Hexanetrinitrile, 1,2,3-tris(2-cyanoethoxy)propane, 1,2,4-tris(2-cyanoethoxy)butane, 1,2,5-tris At least one of (cyanoethoxy)pentane.
  • the electrolyte further comprises a compound of formula I:
  • R 1 , R 2 and R 3 are each independently selected from hydrogen, halogen, C 1 -C 12 alkyl with or without substituents, C 3 -C 8 cycloalkyl with or without substituents, or a C 6 -C 12 aryl group without substituents, the substituents are selected from at least one of cyano, nitro, halogen and sulfonyl, and n is an integer from 0 to 7.
  • R 1 , R 2 and R 3 are each independently selected from hydrogen or C 1 -C 5 alkyl, and n is an integer from 0 to 3.
  • the content of the compound of formula I is A%, which satisfies 1 ⁇ A+X+Y ⁇ 7.
  • the electrolyte further comprises a lithium salt additive comprising at least one of lithium tetrafluoroborate, lithium difluorophosphate, lithium bis-oxalate borate, or lithium difluorooxalate borate.
  • a lithium salt additive comprising at least one of lithium tetrafluoroborate, lithium difluorophosphate, lithium bis-oxalate borate, or lithium difluorooxalate borate.
  • the content of the lithium salt additive is P%, which satisfies 0.1 ⁇ P ⁇ 2.
  • a second aspect of the present application provides an electrochemical device comprising a positive electrode sheet, a negative electrode sheet, a separator, and the electrolyte according to the first aspect of the present application.
  • the positive electrode sheet includes a positive electrode current collector, and the positive electrode current collector includes an aluminum foil substrate and a copper element contained in the aluminum foil substrate. Based on the weight of the positive electrode current collector, the copper element is The content m is in ppm, and the thickness d of the aluminum foil substrate is in ⁇ m, satisfying d ⁇ m/1000 ⁇ 5.
  • 5 ⁇ d ⁇ m/1000 ⁇ 50 5 ⁇ d ⁇ m/1000 ⁇ 50.
  • a third aspect of the present application provides an electronic device, including the electrochemical device described in the second aspect of the present application.
  • a first aspect of the present application provides an electrolyte, comprising a fluorine-containing sulfonimide lithium salt and a trinitrile compound, wherein, based on the weight of the electrolyte, the content of the fluorine-containing sulfonimide lithium salt is X %, the content of the trinitrile compound is Y%, which satisfies 1 ⁇ X+Y ⁇ 6.
  • X+Y 1.25, 1.5, 1.75, 2.0, 2.25, 2.5, 2.75, 3.0, 3.25, 3.5, 3.75, 4.0, 4.25, 4.5, 4.75, 5.0, 5.25, 5.5, 5.75, 6.0 or these Any value between numeric values.
  • 1 ⁇ X ⁇ 5.5 eg X is 1.0, 1.25, 1.5, 1.75, 2.0, 2.25, 2.5, 2.75, 3.0, 3.25, 3.5, 3.75, 4.0, 4.25, 4.5, 4.75, 5.0 , 5.25, 5.5, or any value in between.
  • X is 1.25 ⁇ X ⁇ 5.0.
  • 0.1 ⁇ Y ⁇ 2.5 eg, Y is 0.1, 0.25, 0.5, 0.75, 1.0, 1.25, 1.5, 2.0, 2.25, or any value between these values.
  • 0.5 ⁇ Y ⁇ 2.0 0.5 ⁇ Y ⁇ 2.0.
  • the electrolyte further includes lithium hexafluorophosphate (LiPF 6 ).
  • LiPF 6 lithium hexafluorophosphate
  • the content of lithium hexafluorophosphate is Z % based on the weight of the electrolyte, wherein X+Z ⁇ 7.5, and X/Z ⁇ 1.
  • fluorine-containing sulfonimide lithium salt can improve the self-stability of the electrolyte.
  • the short-circuit heat generation can be significantly reduced, thereby improving the impact and nail penetration. and other mechanical safety performance.
  • Z ⁇ 7.0 According to some embodiments of the invention, Z ⁇ 5.0. According to some embodiments of the present invention, 0.1 ⁇ Z ⁇ 7, eg, Z is 0.1, 0.5, 1.5, 2.0, 2.5, 3.0, 3.75, 4.0, 4.25, 4.75, 5.0, 6.0, or any value between these values. According to some embodiments of the present invention, 2.5 ⁇ Z ⁇ 5.0.
  • the lithium fluorine-containing sulfonimide salt comprises lithium bisfluorosulfonimide (LiFSI) and/or lithium bistrifluoromethanesulfonimide (LiTFSI).
  • the fluorine-containing lithium sulfonimide salt comprises lithium bisfluorosulfonimide (LiFSI) and lithium bistrifluoromethanesulfonimide (LiTFSI).
  • the electrolyte satisfies 0.8 ⁇ (X+Z)/(X+Y) ⁇ 3.5.
  • (X+Z)/(X+Y) is 1.0, 1.2, 1.4, 1.6, 1.8, 2.0, 2.5, 2.8, 3.0, 3.2, 3.4, or 3.5 or any value in between.
  • the electrolyte satisfies 1.2 ⁇ (X+Z)/(X+Y) ⁇ 3.5.
  • the trinitrile compound refers to an organic compound having three cyano groups (—CN).
  • the trinitrile compound includes at least one of a compound of formula II or a compound of formula III:
  • a, d and f are each independently selected from an integer of 1-6, and b, c and e are each independently selected from an integer of 0-6;
  • g, h and i are each independently selected from an integer of 0-6.
  • the trinitrile compound comprises 1,3,5-pentanetricarbonitrile, 1,2,3-propanetricarbonitrile, 1,3,6-hexanetricarbonitrile, 1,2,6 -Hexanetrinitrile, 1,2,3-tris(2-cyanoethoxy)propane, 1,2,4-tris(2-cyanoethoxy)butane, 1,2,5-tris At least one of (cyanoethoxy)pentane.
  • the electrolyte further comprises a compound of formula I:
  • R 1 , R 2 and R 3 are each independently selected from hydrogen, halogen, C 1 -C 12 alkyl with or without substituents, C 3 -C 8 cycloalkyl with or without substituents, or a C 6 -C 12 aryl group without substituents, the substituents are selected from at least one of cyano, nitro, halogen and sulfonyl, and n is an integer from 0 to 7.
  • R 1 , R 2 and R 3 are each independently selected from hydrogen or C 1 -C 5 alkyl, and n is an integer from 0 to 3.
  • the compound of formula I is selected from one or more of allyl nitrile or allyl nitrile.
  • the content of the compound of formula I is A%, which satisfies 1 ⁇ A+X+Y ⁇ 7.
  • the electrolyte further includes a lithium salt additive
  • the lithium salt additive includes lithium tetrafluoroborate (LiBF 4 ), lithium difluorophosphate (LiPO 2 F 2 ), lithium bis(oxalate borate) (LiBOB) ) or at least one of lithium difluorooxalate borate (LiDFOB).
  • the content of the lithium salt additive is P%, which satisfies 0.1 ⁇ P ⁇ 2.
  • a second aspect of the present application provides an electrochemical device comprising a positive electrode sheet, a negative electrode sheet, a separator, and the electrolyte according to the first aspect of the present application.
  • the positive electrode sheet includes a positive electrode current collector, and the positive electrode current collector includes an aluminum foil substrate and a copper element contained in the aluminum foil substrate. Based on the weight of the positive electrode current collector, the copper element is The content m is in ppm, and the thickness d of the aluminum foil substrate is in ⁇ m, satisfying d ⁇ m/1000 ⁇ 5.
  • 5 ⁇ d ⁇ m/1000 ⁇ 50 5 ⁇ d ⁇ m/1000 ⁇ 50.
  • the positive electrode further includes a positive electrode active material disposed on the positive electrode current collector.
  • the specific types of the positive electrode active materials are not specifically limited, and can be selected according to requirements.
  • the positive electrode active material can be selected from lithium cobalt oxide (LiCoO 2 ), lithium nickel manganese cobalt ternary material, lithium manganate (LiMn 2 O 4 ), lithium nickel manganate (LiNi 0.5 Mn 1.5 O 4 ), phosphoric acid
  • LiCoO 2 lithium cobalt oxide
  • LiMn 2 O 4 lithium nickel manganese cobalt ternary material
  • LiMn 2 O 4 lithium manganate
  • LiNi 0.5 Mn 1.5 O 4 lithium nickel manganate
  • phosphoric acid One or more of lithium iron (LiFePO 4 ) and its doping and/or coating modification compounds, but this application is not limited to these materials, and other conventionally known materials that can be used as positive electrode active materials can also be used s material.
  • These positive electrode active materials may be used alone or in combination of two or more.
  • the cathode active material has a coating layer thereon.
  • the coating layer can play the role of isolating the electrolyte, which can greatly reduce the side reaction between the electrolyte and the positive electrode active material, reduce the dissolution of transition metals, and improve the electrochemical stability of the positive electrode active material.
  • the coating layer can be a carbon layer, a graphene layer, an oxide layer, an inorganic salt layer or a conductive polymer layer.
  • Oxides can be oxides formed by one or several elements of Al, Ti, Mn, Zr, Mg, Zn, Ba, Mo, B; inorganic salts can be Li 2 ZrO 3 , LiNbO 3 , Li 4 Ti 5 One or more of O 12 , Li 2 TiO 3 , Li 3 VO 4 , LiSnO 3 , Li 2 SiO 3 , LiAlO 2 ; the conductive polymer can be polypyrrole (PPy), polyethylene 3,4-ethylene oxythiophene (PEDOT) or polyamide (PI).
  • PPPy polypyrrole
  • PEDOT polyethylene 3,4-ethylene oxythiophene
  • PI polyamide
  • the anode of the electrochemical device includes a current collector and an anode active material layer formed on the current collector, the anode active material layer includes an anode active material, and the anode active material may include a material that reversibly intercalates/deintercalates lithium ions, lithium Metals, lithium metal alloys, materials capable of doping/dedoping lithium, or transition metal oxides such as Si, SiO x (0 ⁇ x ⁇ 2), etc.
  • the material that reversibly intercalates/deintercalates lithium ions may be a carbon material.
  • the carbon material may be any carbon-based negative active material commonly used in lithium-ion rechargeable electrochemical devices. Examples of carbon materials include crystalline carbon, amorphous carbon, and combinations thereof.
  • Crystalline carbon can be amorphous or plate-shaped, platelet-shaped, spherical or fibrous natural graphite or artificial graphite.
  • the amorphous carbon can be soft carbon, hard carbon, mesophase pitch carbonization product, fired coke, and the like. Both low-crystalline carbon and high-crystalline carbon can be used as the carbon material.
  • soft carbon and hard carbon can be generally included.
  • highly crystalline carbon material natural graphite, crystalline graphite, pyrolytic carbon, mesophase pitch-based carbon fibers, mesophase carbon microbeads, mesophase pitch, and high temperature calcined carbon (such as petroleum or coke derived from coal tar pitch may be generally included) ).
  • the negative electrode active material layer contains a binder
  • the binder may include various binder polymers, such as vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinylidene Vinyl difluoride, polyacrylonitrile, polymethyl methacrylate, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene-containing Oxygen polymer, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, nylon, etc., but not limited thereto.
  • PVDF-co-HFP vinylidene fluoride-hexafluoropropylene copolymer
  • PVDF-co-HFP polyvin
  • the anode active material layer further includes a conductive material to improve electrode conductivity.
  • a conductive material can be used as the conductive material as long as it does not cause chemical change.
  • conductive materials include: carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, carbon fibers, etc.; metal-based materials such as metal powders or metal fibers including copper, nickel, aluminum, silver, etc. ; Conductive polymers, such as polyphenylene derivatives, etc.; or their mixtures.
  • the current collector may be copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with conductive metal, or a combination thereof.
  • the material and shape of the separator used in the electrochemical device of the present application are not particularly limited, and it may be any technique disclosed in the prior art.
  • the separator includes a polymer or inorganic or the like formed from a material that is stable to the electrolyte of the present application.
  • the separator may include a substrate layer and a surface treatment layer.
  • the base material layer is a non-woven fabric, film or composite film with a porous structure, and the material of the base material layer is selected from at least one of polyethylene, polypropylene, polyethylene terephthalate and polyimide.
  • a polypropylene porous membrane, a polyethylene porous membrane, a polypropylene non-woven fabric, a polyethylene non-woven fabric or a polypropylene-polyethylene-polypropylene porous composite membrane can be selected.
  • At least one surface of the base material layer is provided with a surface treatment layer, and the surface treatment layer may be a polymer layer or an inorganic material layer, or a layer formed by mixing a polymer and an inorganic material.
  • the inorganic layer includes inorganic particles and a binder, and the inorganic particles are selected from aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, hafnium oxide, tin oxide, ceria, nickel oxide, zinc oxide, calcium oxide, zirconium oxide, At least one 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, polyvinylalkoxy , at least one of polymethyl methacrylate, polytetrafluoroethylene and polyhexafluoropropylene.
  • the polymer layer contains a polymer, and the material of the polymer is selected from polyamide, polyacrylonitrile, acrylate polymer, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyvinylalkoxy, polyvinylidene fluoride, At least one of poly(vinylidene fluoride-hexafluoropropylene).
  • Electronic devices or devices to which the electrochemical device of the present application can be applied are not particularly limited.
  • electronic devices include, but are not limited to, notebook computers, pen input computers, mobile computers, e-book players, portable telephones, portable fax machines, portable copiers, portable printers, headsets, video recorders, LCD TVs, Portable Cleaners, Portable CD Players, Mini CD-ROMs, Transceivers, Electronic Notepads, Calculators, Memory Cards, Portable Recorders, Radios, Backup Power, Motors, Automobiles, Motorcycles, Bicycles, Bicycles, Lighting Appliances , toys, game consoles, clocks, power tools, flashes, cameras, large household batteries and lithium-ion capacitors, etc.
  • any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with any other lower limit to form an unspecified range, and likewise any upper limit can be combined with any other upper limit to form an unspecified range.
  • each individually disclosed point or single value may itself serve as a lower or upper limit in combination with any other point or single value or with other lower or upper limits to form a range that is not expressly recited.
  • a list of items to which the terms "at least one of,” “at least one of,” or other similar terms are linked can mean any combination of the listed items. For example, if items A and B are listed, the phrase “at least one of A and B” means A only; B only; or A and B. In another example, if items A, B, and C are listed, the phrase "at least one of A, B, and C" means A only; or B only; C only; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B, and C.
  • Item A may contain a single component or multiple components.
  • Item B may contain a single component or multiple components.
  • Item C may contain a single component or multiple components.
  • hydrocarbyl encompasses alkyl, alkenyl, alkynyl.
  • alkyl is intended to be a straight chain saturated hydrocarbon structure having from 1 to 20 carbon atoms. "Alkyl” is also contemplated to be a branched or cyclic hydrocarbon structure having 3 to 20 carbon atoms. When specifying an alkyl group having a specific carbon number, it is intended to encompass all geometric isomers having that carbon number; thus, for example, “butyl” is meant 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 et al.
  • alkenyl refers to a monovalent unsaturated hydrocarbon group which may be straight or branched and having at least one and usually 1, 2 or 3 carbon-carbon double bonds. Unless otherwise defined, the alkenyl groups generally contain from 2 to 20 carbon atoms and include, for example, C2 - C4 alkenyl, C2 - C6 alkenyl, and C2 - C10 alkenyl. Representative alkenyl groups include, for example, vinyl, n-propenyl, isopropenyl, n-but-2-enyl, but-3-enyl, n-hex-3-enyl, and the like.
  • alkynyl refers to a monovalent unsaturated hydrocarbon group which may be straight or branched and having at least one and usually one, two or three carbon-carbon triple bonds. Unless otherwise defined, the alkynyl groups generally contain from 2 to 20 carbon atoms and include, for example, C2 - C4 alkynyl, C3 - C6 alkynyl, and C3 - C10 alkynyl. Representative alkynyl groups include, for example, ethynyl, prop-2-ynyl (n-propynyl), n-but-2-ynyl, n-hex-3-ynyl, and the like.
  • the content of each component is the percentage content based on the weight of the electrolyte.
  • the lithium ion batteries in the examples and comparative examples were prepared according to the following methods:
  • ethylene carbonate (EC), propylene carbonate (PC), and diethyl carbonate (DEC) are uniformly mixed in a weight ratio of 1:1:1, refer to Table 1- 5 Add the components and stir evenly to form an electrolyte.
  • the positive active material lithium cobalt oxide (LiCoO 2 ), the conductive agent carbon nanotube (CNT), and the specific binder polyvinylidene fluoride are mixed in a weight ratio of 95:2:3, and N-methylpyrrolidone (NMP) is added. , stir the system under the action of a vacuum mixer until the system becomes a uniform positive electrode slurry, and then evenly coat the positive electrode slurry on the positive electrode current collector aluminum foil; Dry under vacuum at 85°C for 4 hours to obtain a positive electrode sheet.
  • NMP N-methylpyrrolidone
  • the negative electrode active material graphite, binder styrene-butadiene rubber (SBR), and thickener sodium carboxymethyl cellulose (CMC) are fully stirred and mixed in an appropriate amount of deionized water solvent according to the weight ratio of 95:2:3 to make it.
  • a uniform negative electrode slurry is formed; the slurry is coated on the copper foil of the negative electrode current collector, dried and cold pressed to obtain a negative electrode sheet.
  • the separator is a polyethylene (PE) separator with a thickness of 5 ⁇ m.
  • the positive electrode sheet, the separator film and the negative electrode sheet are stacked in order so that the separator film is placed between the positive electrode sheet and the negative electrode sheet to isolate the positive electrode sheet and the negative electrode sheet.
  • the preparation of the lithium ion battery is completed after vacuum packaging, standing, chemical formation, shaping and other processes.
  • the lithium-ion battery was charged to 4.45V with a constant current of 0.5C, charged to a current of 0.05C with a constant voltage of 4.45V, and then discharged to 3.0V with a constant current of 0.5C. This is the first cycle.
  • the lithium-ion battery was cycled a number of times under the above conditions. Taking the capacity of the first discharge as 100%, the charge-discharge cycle was repeated, and when the discharge capacity decreased to 80%, the test was stopped, and the number of cycles was recorded as an index to evaluate the cycle performance of the lithium-ion battery.
  • the lithium-ion battery was charged to 4.5V with a constant current of 0.7C and a constant voltage of 4.5V to a current of 0.05C.
  • the battery was placed in a high temperature box, heated to 135 °C with a temperature rise rate of 5 ⁇ 2 °C/min, and then kept for 1 h, and the voltage, temperature and temperature of the hot box were recorded. The test is passed if the battery does not catch fire, explode, or emit smoke. Test 10 batteries in each group, and record the number of batteries that pass the test.
  • the system When the total amount of LiPF 6 and fluorine-containing sulfonimide lithium salt is within a certain range, the system generates less heat, and at the same time, the electrode interface is stabilized by the synergistic effect of LiPF 6 , fluorine-containing sulfonimide lithium salt and trinitrile compound. , reduce the oxygen release of the positive electrode, and then achieve a balance between the improvement of battery safety performance and cycle performance.
  • the cycle performance of the hybrid lithium salt system battery is significantly improved, which is mainly due to the gap between the pole piece and the electrolyte.
  • the interface stability is significantly enhanced: the trinitrile additive mainly acts on the positive electrode interface, and the double bond-containing single nitrile has a double bond, its oxidation potential is low, and its reduction potential is high, which can form a protective film at the interface of the pole piece. While protecting the positive electrode sheet, it can also strengthen the stability of the negative electrode interface, thereby significantly improving the cycle performance of the battery.
  • S5-1 to S5-3 and S4-1 is only the difference of the positive electrode current collector aluminum foil, see Table 5 for details.
  • the thickness of the aluminum foil base material decreases, and the pass rate of the nail penetration test is significantly reduced, but by increasing the copper content in the aluminum foil base material, the pass rate of the nail penetration test can be further improved.
  • the data of S5-3 it can be seen that when the thickness of the substrate and the copper content satisfy d ⁇ m/1000 ⁇ 5, the safety performance of the battery is better, and if it is lower than this value, the safety performance will deteriorate significantly.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • General Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Manufacturing & Machinery (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)

Abstract

本申请涉及一种电解液以及包含该电解液的电化学装置。该电解液包括含氟磺酰亚胺锂盐和三腈化合物，其中，基于所述电解液的重量，所述含氟磺酰亚胺锂盐的含量为X％，所述三腈化合物的含量为Y％，满足1≤X+Y≤6。本申请的电解液能够显著提高锂离子电池的安全性能。

Description

一种电解液及含有该电解液的电化学装置 技术领域
本申请涉及储能领域，具体涉及一种电解液及含有该电解液的电化学装置。
背景技术
随着智能产品的普及和应用，人们对手机、笔记本、相机等电子产品的需求逐年增加。锂离子电池作为电子产品的工作电源，具有能量密度高、无记忆效应、工作电压高等特点，正逐步取代传统的Ni-Cd、MH-Ni电池。然而随着锂离子电池的发展，人们对锂离子电池安全性能的要求不断提高，开发更高安全的锂离子电池是市场的主要需求之一。
发明内容
本申请第一方面提供一种电解液，其包括含氟磺酰亚胺锂盐和三腈化合物，其中，基于所述电解液的重量，所述含氟磺酰亚胺锂盐的含量为X％，所述三腈化合物的含量为Y％，满足1≤X+Y≤6。本发明的电解液能够提高锂离子电池的安全性能。
根据本发明的一些实施方式，所述电解液进一步包括六氟磷酸锂(LiPF 6)。根据本申请的一些实施方式，基于所述电解液的重量，六氟磷酸锂的含量为Z％，其中X+Z≤7.5，且X/Z≤1。
根据本发明的一些实施方式，所述含氟磺酰亚胺锂盐包含双氟磺酰亚胺锂(LiFSI)或双三氟甲烷磺酰亚胺锂(LiTFSI)中的一种或两种。
根据本发明的一些实施方式，所述电解液满足以下条件(a)或(b)中的至少一者：(a)Z小于5；(b)0.8≤(X+Z)/(X+Y)≤3.5。
根据本发明的一些实施方式，所述三腈化合物包括式II化合物或式III化合物中的至少一种：
Figure PCTCN2021084094-appb-000001
式II中，a、d和f各自独立地选自1-6的整数，b、c和e各自独立地选自0-6的整数；
式III中，g、h和i各自独立地选自0-6的整数。
根据本发明的一些实施方式，所述三腈化合物包含1,3,5-戊三甲腈、1,2,3-丙三甲腈、1,3,6-己烷三腈、1,2,6-己烷三腈、1,2,3-三(2-氰基乙氧基)丙烷、1,2,4-三(2-氰基乙氧基)丁烷、1,2,5-三(氰基乙氧基)戊烷中的至少一种。
根据本发明的一些实施方式，所述的电解液进一步包含式I化合物：
Figure PCTCN2021084094-appb-000002
其中R 1、R 2、R 3各自独立地选自氢、卤素、含或不含取代基的C 1-C 12烷基、含或不含取代基的C 3-C 8环烷基、含或不含取代基的C 6-C 12芳基，所述的取代基选自氰基、硝基、卤素和磺酰基中的至少一种，n为0至7的整数。
根据本发明的一些实施方式，式I中，R 1、R 2、R 3各自独立地选自氢或C 1-C 5烷基、n为0至3的整数。
根据本发明的一些实施方式，基于所述电解液的重量，所述式I化合物的含量为A％，满足1≤A+X+Y≤7。
根据本发明的一些实施方式，所述电解液进一步包含锂盐添加剂，所述锂盐添加剂包含四氟硼酸锂、二氟磷酸锂、双草酸硼酸锂或二氟草酸硼酸锂中的至少一种。根据本申请的一些实施方式，基于所述电解液的重量，所述锂盐添加剂的含量为P％，满足0.1≤P≤2。
本申请的第二方面提供了一种电化学装置，其包括正极片、负极片、隔离膜以及本申请的第一个方面所述的电解液。
根据本发明的一些实施方式，所述正极片包括正极集流体，所述正极集流体包括铝箔基材和包含在所述铝箔基材中的铜元素，基于所述正极集流体的重量，铜元素的含量m 以ppm计，铝箔基材的厚度d以μm计，满足d×m/1000≥5。
根据本发明的一些实施方式，5≤d×m/1000≤50。
根据本发明的一些实施方式，0＜m≤2000ppm。
本申请的第三方面提供了一种电子设备，包括本申请的第二方面所述的电化学装置。
具体实施方式
下面结合具体实施方式，进一步阐述本申请。应理解，这些具体实施方式仅用于说明本申请而不用于限制本申请的范围。
本申请第一方面提供一种电解液，其包括含氟磺酰亚胺锂盐和三腈化合物，其中，基于所述电解液的重量，所述含氟磺酰亚胺锂盐的含量为X％，所述三腈化合物的含量为Y％，满足1≤X+Y≤6。根据一些实施例，X+Y＝1.25、1.5、1.75、2.0、2.25、2.5、2.75、3.0、3.25、3.5、3.75、4.0、4.25、4.5、4.75、5.0、5.25、5.5、5.75、6.0或这些数值之间的任意值。
根据本发明的一些实施方式，1≤X≤5.5，例如X为1.0、1.25、1.5、1.75、2.0、2.25、2.5、2.75、3.0、3.25、3.5、3.75、4.0、4.25、4.5、4.75、5.0、5.25、5.5或这些数值之间的任意值。根据本发明的一些实施方式，X为1.25≤X≤5.0。
根据本发明的一些实施方式，0.1≤Y≤2.5，例如Y为0.1、0.25、0.5、0.75、1.0、1.25、1.5、2.0、2.25或这些数值之间的任意值。根据本发明的一些实施方式，0.5≤Y≤2.0。
根据本发明的一些实施方式，所述电解液进一步包括六氟磷酸锂(LiPF 6)。根据本申请的一些实施方式，基于所述电解液的重量，六氟磷酸锂的含量为Z％，其中X+Z≤7.5，且X/Z≤1。含氟磺酰亚胺锂盐的引入可以提高电解液的自身稳定性，同时其与六氟磷酸锂浓度之和较低时，可显著减小短路产热量，从而改善撞击(Impact)、穿钉(Nail)等机械安全性能。
根据本发明的一些实施方式，Z≤7.0。根据本发明的一些实施方式，Z＜5.0。根据本发明的一些实施方式，0.1≤Z≤7，例如Z为0.1、0.5、1.5、2.0、2.5、3.0、3.75、4.0、4.25、4.75、5.0、6.0或这些数值之间的任意值。根据本发明的一些实施方式，2.5≤Z≤5.0。
根据本发明的一些实施方式，所述含氟磺酰亚胺锂盐包含双氟磺酰亚胺锂(LiFSI)和/或双三氟甲烷磺酰亚胺锂(LiTFSI)。在一些实施例中，所述含氟磺酰亚胺锂盐包含 双氟磺酰亚胺锂(LiFSI)和双三氟甲烷磺酰亚胺锂(LiTFSI)。
根据本发明的一些实施方式，所述电解液满足0.8≤(X+Z)/(X+Y)≤3.5。在一些实施例中，(X+Z)/(X+Y)为1.0、1.2、1.4、1.6、1.8、2.0、2.5、2.8、3.0、3.2、3.4或3.5或这些数值之间的任意值。根据本发明的一些实施方式，所述电解液满足1.2≤(X+Z)/(X+Y)≤3.5。
本申请中，三腈化合物指具有三个氰基(-CN)的有机化合物。根据本发明的一些实施方式，所述三腈化合物包括式II化合物或式III化合物中的至少一种：
Figure PCTCN2021084094-appb-000003
式II中，a、d和f各自独立地选自1-6的整数，b、c和e各自独立地选自0-6的整数；
式III中，g、h和i各自独立地选自0-6的整数。
根据本发明的一些实施方式，所述三腈化合物包含1,3,5-戊三甲腈、1,2,3-丙三甲腈、1,3,6-己烷三腈、1,2,6-己烷三腈、1,2,3-三(2-氰基乙氧基)丙烷、1,2,4-三(2-氰基乙氧基)丁烷、1,2,5-三(氰基乙氧基)戊烷中的至少一种。
根据本发明的一些实施方式，所述的电解液进一步包含式I化合物：
Figure PCTCN2021084094-appb-000004
其中R 1、R 2、R 3各自独立地选自氢、卤素、含或不含取代基的C 1-C 12烷基、含或不含取代基的C 3-C 8环烷基、含或不含取代基的C 6-C 12芳基，所述的取代基选自氰基、硝基、卤素和磺酰基中的至少一种，n为0至7的整数。
根据本发明的一些实施方式，式I中，R 1、R 2、R 3各自独立地选自氢或C 1-C 5烷基、n为0至3的整数。在一些实施例中，式I化合物选自烯丙基腈或烯丁基腈中的一种或几种。
根据本发明的一些实施方式，基于所述电解液的重量，所述式I化合物的含量为A％，满足1≤A+X+Y≤7。
根据本发明的一些实施方式，所述电解液进一步包含锂盐添加剂，所述锂盐添加剂包 含四氟硼酸锂(LiBF 4)、二氟磷酸锂(LiPO 2F 2)、双草酸硼酸锂(LiBOB)或二氟草酸硼酸锂(LiDFOB)中的至少一种。根据本申请的一些实施方式，基于所述电解液的重量，所述锂盐添加剂的含量为P％，满足0.1≤P≤2。
本申请的第二个方面提供了一种电化学装置，其包括正极片、负极片、隔离膜以及本申请的第一个方面所述的电解液。
根据本发明的一些实施方式，所述正极片包括正极集流体，所述正极集流体包括铝箔基材和包含在所述铝箔基材中的铜元素，基于所述正极集流体的重量，铜元素的含量m以ppm计，铝箔基材的厚度d以μm计，满足d×m/1000≥5。
根据本发明的一些实施方式，5≤d×m/1000≤50。
根据本发明的一些实施方式，0＜m≤2000ppm。
在根据本申请所述的电化学装置中，正极还包括设置在所述正极集流体上的正极活性材料。正极活性材料的具体种类均不受到具体的限制，可根据需求进行选择。
所述正极活性材料可选自选自钴酸锂(LiCoO 2)、锂镍锰钴三元材料、锰酸锂(LiMn 2O 4)、镍锰酸锂(LiNi 0.5Mn 1.5O 4)、磷酸铁锂(LiFePO 4)及其掺杂和/或包覆改性化合物中的一种或几种，但本申请并不限定于这些材料，还可以使用其他可被用作正极活性材料的传统公知的材料。这些正极活性材料可以仅单独使用一种，也可以将两种以上组合使用。
在一些实施方式中，正极活性材料上具有一层包覆层。包覆层可以起到隔绝电解液的作用，可以在很大程度上减少电解液与正极活性材料之间的副反应，减少过渡金属溶出，提高正极活性材料的电化学稳定性。其中，包覆层可为碳层、石墨烯层、氧化物层、无机盐层或导电高分子层。氧化物可为Al、Ti、Mn、Zr、Mg、Zn、Ba、Mo、B中的一种或几种元素形成的氧化物；无机盐可为Li 2ZrO 3、LiNbO 3、Li 4Ti 5O 12、Li 2TiO 3、Li 3VO 4、LiSnO 3、Li 2SiO 3、LiAlO 2中的一种或几种；导电高分子可为聚吡咯(PPy)、聚3,4-亚乙二氧基噻吩(PEDOT)或聚酰胺(PI)。
根据本申请的电化学装置的负极包括集流体和形成在集流体上的负极活性物质层，负极活性物质层包括负极活性物质，负极活性物质可以包括可逆地嵌入/脱嵌锂离子的材料、锂金属、锂金属合金、能够掺杂/脱掺杂锂的材料或过渡金属氧化物，例如Si、SiO x(0<x<2)等材料。可逆地嵌入/脱嵌锂离子的材料可以是碳材料。碳材料可以是在锂离子可再充电电化学装置中通常使用的任何碳基负极活性物质。碳材料的示例包括结晶碳、非晶碳和它 们的组合。结晶碳可以是无定形的或板形的、小片形的、球形的或纤维形的天然石墨或人造石墨。非晶碳可以是软碳、硬碳、中间相沥青碳化产物、烧制焦炭等。低结晶碳和高结晶碳均可以用作碳材料。作为低结晶碳材料，可通常包括软碳和硬碳。作为高结晶碳材料，可通常包括天然石墨、结晶石墨、热解碳、中间相沥青基碳纤维、中间相碳微珠、中间相沥青和高温锻烧炭(如石油或衍生自煤焦油沥青的焦炭)。
根据一些实施方式，负极活性物质层包含有粘合剂，且该粘合剂可以包括各种粘合剂聚合物，如二氟乙烯-六氟丙烯共聚物(PVDF-co-HFP)，聚偏二氟乙烯、聚丙烯睛、聚甲基丙烯酸甲醋、聚乙烯醇、羧甲基纤维素、羟丙基纤维素、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，但不限于此等。
根据一些实施方式，负极活性物质层还包括导电材料来改善电极导电率。可以使用任何导电的材料作为该导电材料，只要它不引起化学变化即可。导电材料的示例包括：碳基材料，例如天然石墨、人造石墨、炭黑、乙炔黑、科琴黑、碳纤维等；金属基材料，例如包括铜、镍、铝、银等的金属粉或金属纤维；导电聚合物，例如聚亚苯基衍生物等；或它们的混合物。集流体可以为铜箔、镍箔、不锈钢箔、钛箔、泡沫镍、泡沫铜、包覆有导电金属的聚合物基板或它们的组合。
本申请的电化学装置中使用的隔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至少一种。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、聚乙烯烷氧、聚甲基丙烯酸甲酯、聚四氟乙烯和聚六氟丙烯中的至少一 种。
聚合物层中包含聚合物，聚合物的材料选自聚酰胺、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、聚乙烯烷氧、聚偏氟乙烯、聚(偏氟乙烯-六氟丙烯)中的至少一种。
本申请的电化学装置可应用的电子设备或装置没有特别限定。在一些实施例中，电子设备包括但不限于，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。
为了简明，本文仅具体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，每个单独公开的点或单个数值自身可以作为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。
术语“中的至少一个”、“中的至少一种”或其他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及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”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。
术语“烃基”涵盖烷基、烯基、炔基。
术语“烷基”预期是具有1至20个碳原子的直链饱和烃结构。“烷基”还预期是具有3至20个碳原子的支链或环状烃结构。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。
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个到20个碳原子且包括(例如)C 2-C 4烯基、C 2-C 6烯基及C 2-C 10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。
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个到20个碳原子且包括(例如)C 2-C 4炔基、C 3-C 6炔基及C 3-C 10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。
如本文中所使用，各组分的含量均为基于电解液重量的百分含量。
1、电池制备
实施例以及对比例中的锂离子电池均按照下述方法进行制备：
(1)电解液制备
在含水量<10ppm的氩气气氛手套箱中，将碳酸乙烯酯(EC)、碳酸丙烯酯(PC)、碳酸二乙酯(DEC)按重量比1:1:1均匀混合，参照表1-5添加各组分，搅拌均匀，形成电解液。
(2)正极片制备
将正极活性材料钴酸锂(LiCoO 2)、导电剂碳纳米管(CNT)、特定粘结剂聚偏二氟乙烯按照重量比95:2:3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至体系成均一状正极浆料，然后将正极浆料均匀涂覆于正极集流体铝箔上；在85℃下烘干后经过冷压、裁片、分切后，在85℃的真空条件下干燥4h，得到正极片。
(3)负极片制备
将负极活性物质石墨、粘结剂丁苯橡胶(SBR)、增稠剂羧甲基纤维素钠(CMC)按照重量比95:2:3在适量的去离子水溶剂中充分搅拌混合，使其形成均匀的负极浆料；将此浆料涂覆于负极集流体铜箔上，烘干、冷压，得到负极片。
(4)隔离膜制备
隔离膜选用厚度为5μm的聚乙烯(PE)隔膜。
(5)锂离子电池的制备
将正极片、隔离膜、负极片按顺序叠好，使隔离膜处于正极片和负极片之间起到隔离的作用，然后卷绕，置于外包装箔中，将上述制备好的电解液注入到干燥后的电池中，经 过真空封装、静置、化成、整形等工序，即完成锂离子电池的制备。
2、测试方法
(1)穿钉测试
取10枚待测的电化学装置(锂离子电池)在常温下以0.5C倍率恒定电流充电至电压4.45V，进一步在4.45V恒定电压下充电至电流0.05C，使其处于4.45V满充状态。之后在常温条件下对锂离子电池进行穿钉，采用直径为2.5mm钉子(钢钉，材质为碳钢，锥度为16.5mm，钢钉总长为100mm)，以30mm/s的穿钉速度穿钉，穿钉深度以钢钉锥度穿过锂离子电池为准，观察锂离子电池是否产烟、起火或爆炸。若没有则认为锂离子电池通过穿钉测试。每组测试10个电池，记录通过测试电池个数。
(2)锂离子电池的室温容量保持率的测试方法
在25℃下，将锂离子电池以0.5C恒流充电至4.45V，4.45V恒压充电至电流为0.05C，再用0.5C恒流放电至3.0V，此时为首次循环。按照上述条件使锂离子电池进行多次循环。以首次放电的容量为100％，反复进行充放电循环，至放电容量衰减至80％时，停止测试，记录循环圈数，作为评价锂离子电池循环性能的指标。
(3)热箱测试
在25℃下，将锂离子电池以0.7C恒流充电至4.5V，4.5V恒压充电至电流为0.05C。将电池放置在高温箱中，用5±2℃/分钟的温升速率加热到135℃，然后保持1h，记录电池的电压、温度以及热箱温度的变化。电池不起火、不爆炸、不冒烟即为通过测试。每组测试10个电池，记录通过测试电池个数。
3、测试结果
(1)含氟磺酰亚胺锂盐和三腈化合物对电池性能的影响
表1
Figure PCTCN2021084094-appb-000005
Figure PCTCN2021084094-appb-000006
表1可以看出，在一定范围内，含氟磺酰亚胺锂盐含量降低，电池的穿钉通过率逐步提高，即电池的安全性能不断得到提升，但循环性能受到明显影响。随着三腈化合物(此处以1,3,6己烷三腈为例)的引入穿钉通过率有显著提高，主要归因于三腈类化合物对正极界面稳定性的增强，且与含氟磺酰亚胺锂盐协同作用，二者共同提高了电解液的稳定性，从而在改善电池循环性能的同时，显著改善了电池的安全性能。当含氟磺酰亚胺锂盐与三腈类化合物含量之和增加时，体系在穿钉测试中产热量增加，电池容易失效，且电解液成本随之升高，因此两者含量之和须保持在一定合理范围内。
(2)含氟磺酰亚胺锂盐+三腈化合物+LiPF 6对电池性能的影响
表2-1
Figure PCTCN2021084094-appb-000007
由实施例S2-1至S2-9与对比例D2-1至D2-3、实施例S1-3至实施例S1-4的比较可知，LiPF 6、含氟磺酰亚胺锂盐与三腈化合物在一定浓度范围内共用，在电解液中LiPF 6、含氟磺酰亚胺锂盐总含量较低的情况下，多种锂盐共用较单一锂盐体系对于穿钉改善效果更为明显，同时可减少部分原料成本，带来明显的经济效益。当LiPF 6及含氟磺酰亚胺锂盐用量之和在一定范围内时，体系产热量较少，同时通过LiPF 6、含氟磺酰亚胺锂盐及三腈化合物的协同作用稳定电极界面，减少正极释氧，进而达到对于电池安全性能及循环性能改善的平衡。
由实施例S2-5至S2-8对比实施例S2-9可知，当LiPF 6与含氟磺酰亚胺盐含量比值X/Z小于或等于1时，电池循环性能维持较为稳定，当其大于1时，循环性能受到影响，推测与LiPF 6抑制了含氟磺酰亚胺盐对铝箔的腐蚀有关。
表2-2
Figure PCTCN2021084094-appb-000008
由表2-2可以看出，当LiPF 6浓度超过一定范围，电池的热箱通过率随着LiPF 6用量的增加逐渐降低，这可能是由于LiPF 6的热分解产物在该电解液体系下引发进一步反应，产热增加，进而影响电池的安全性能。
(3)含氟磺酰亚胺锂盐+三腈化合物+含双键单腈+LiPF 6对电池性能的影响
表3
Figure PCTCN2021084094-appb-000009
Figure PCTCN2021084094-appb-000010
表3可以看出，随着含双键单腈(此处以烯丙基腈为例)的进一步引入，混合锂盐体系电池的循环性能得到明显改善，这主要归因于极片与电解液间的界面稳定性的显著增强：其中三腈类添加剂主要作用在正极界面，含双键单腈因具有双键，其氧化电位偏低，还原电位较高，可以在极片界面形成保护膜，在保护正极极片的同时，亦可强化负极界面的稳定性，进而显著改善电池的循环性能。
对比实施例S3-10、对比例D3-1至D3-2可以看出，在本申请所述的电解液体系下，相较于前述实施例中含双键单腈的引入对于体系循环性能的显著改善，当X+Y较大时，含双键单腈对体系循环性能的影响不明显。
(4)含氟磺酰亚胺锂盐+三腈化合物+锂盐添加剂对电池性能的影响
表4
Figure PCTCN2021084094-appb-000011
表4可以看出，LiBOB或LiDFOB等其他锂盐的添加，对于多盐低用量体系的循环稳定性亦有明显提升。这主要归因于上述锂盐添加剂对正极较好的稳定性，可减少过渡金属的溶出，多种锂盐和添加剂协同作用，共同提高正极结构的稳定性，同时也可减少过渡金属对负极SEI的破坏，进而在保证电池安全性能的同时提高循环性能。
(5)铝箔对电池性能的影响
S5-1至S5-3与S4-1的区别仅在于正极集流体铝箔不同，具体参见表5。
表5
Figure PCTCN2021084094-appb-000012
表5可以看出，铝箔基材厚度降低，穿钉测试的通过率有明显降低，但通过提升铝箔基材中的铜元素含量，可使得穿钉测试的通过率进一步提升。同时对比S5-3的数据可以看出，当基材厚度与铜含量满足d×m/1000≥5时，电池的安全性能较好，如果低于该值则会导致明显的安全性能恶化。

Claims (10)

  1. 一种电解液，包括含氟磺酰亚胺锂盐和三腈化合物，其中，基于所述电解液的重量，所述含氟磺酰亚胺锂盐的含量为X％，所述三腈化合物的含量为Y％，满足1≤X+Y≤6。
  2. 根据权利要求1所述的电解液，进一步包括六氟磷酸锂，其中，基于所述电解液的重量，六氟磷酸锂的含量为Z％，其中X+Z≤7.5，且X/Z≤1。
  3. 根据权利要求2所述的电解液，满足以下条件(a)或(b)中的至少一者：(a)Z小于5；(b)0.8≤(X+Z)/(X+Y)≤3.5。
  4. 根据权利要求1所述的电解液，其中，所述含氟磺酰亚胺锂盐包含双氟磺酰亚胺锂和/或双三氟甲烷磺酰亚胺锂。
  5. 根据权利要求1所述的电解液，其中，所述三腈化合物包括式II化合物或式III化合物中的至少一种：
    Figure PCTCN2021084094-appb-100001
    式II中，a、d和f各自独立地选自1-6的整数，b、c和e各自独立地选自0-6的整数；
    式III中，g、h和i各自独立地选自0-6的整数。
  6. 根据权利要求1所述的电解液，其中，所述三腈化合物包含1,3,5-戊三甲腈、1,2,3-丙三甲腈、1,3,6-己烷三腈、1,2,6-己烷三腈、1,2,3-三(2-氰基乙氧基)丙烷、1,2,4-三(2-氰基乙氧基)丁烷、1,2,5-三(氰基乙氧基)戊烷中的至少一种。
  7. 根据权利要求1所述的电解液，进一步包含式I化合物：
    Figure PCTCN2021084094-appb-100002
    其中R 1、R 2、R 3各自独立地选自氢、卤素、含或不含取代基的C 1-C 12烷基、含或不含取代基的C 3-C 8环烷基、含或不含取代基的C 6-C 12芳基，所述的取代基选自氰基、硝基、卤素和磺酰基中的至少一种，n为0至7的整数；
    其中，基于所述电解液的重量，所述式I化合物的含量为A％，满足1≤A+X+Y≤7。
  8. 根据权利要求1所述的电解液，进一步包含锂盐添加剂，所述锂盐添加剂包含四氟硼酸锂、二氟磷酸锂、双草酸硼酸锂或二氟草酸硼酸锂中的至少一种；
    其中，基于所述电解液的重量，所述锂盐添加剂的含量为P％，满足0.1≤P≤2。
  9. 一种电化学装置，包括正极片、负极片、隔离膜以及权利要求1-8中任一项所述的电解液。
  10. 根据权利要求9所述的电化学装置，其中，所述正极片包括正极集流体，所述正极集流体包括铝箔基材和包含在所述铝箔基材中的铜元素，基于所述正极集流体的重量，铜元素的含量m以ppm计，铝箔基材的厚度d的单位以μm计，满足d×m/1000≥5。
PCT/CN2021/084094 2021-03-30 2021-03-30 一种电解液及含有该电解液的电化学装置 WO2022204980A1 (zh)

Priority Applications (5)

Application Number Priority Date Filing Date Title
CN202180004970.7A CN114556662A (zh) 2021-03-30 2021-03-30 一种电解液及含有该电解液的电化学装置
PCT/CN2021/084094 WO2022204980A1 (zh) 2021-03-30 2021-03-30 一种电解液及含有该电解液的电化学装置
EP21933661.7A EP4300651A4 (en) 2021-03-30 2021-03-30 ELECTROLYTE AND ELECTROCHEMICAL DEVICE CONTAINING AN ELECTROLYTE
BR112023019937A BR112023019937A2 (pt) 2021-03-30 2021-03-30 Eletrólito e aparelho eletroquímico
US18/373,983 US20240021878A1 (en) 2021-03-30 2023-09-28 Electrolyte and electrochemical apparatus containing such electrolyte

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2021/084094 WO2022204980A1 (zh) 2021-03-30 2021-03-30 一种电解液及含有该电解液的电化学装置

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US18/373,983 Continuation US20240021878A1 (en) 2021-03-30 2023-09-28 Electrolyte and electrochemical apparatus containing such electrolyte

Publications (1)

Publication Number Publication Date
WO2022204980A1 true WO2022204980A1 (zh) 2022-10-06

Family

ID=81669390

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2021/084094 WO2022204980A1 (zh) 2021-03-30 2021-03-30 一种电解液及含有该电解液的电化学装置

Country Status (5)

Country Link
US (1) US20240021878A1 (zh)
EP (1) EP4300651A4 (zh)
CN (1) CN114556662A (zh)
BR (1) BR112023019937A2 (zh)
WO (1) WO2022204980A1 (zh)

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004207117A (ja) * 2002-12-26 2004-07-22 Toyo Aluminium Kk 集電体用アルミニウム箔、集電体および二次電池
CN102738511A (zh) * 2012-01-09 2012-10-17 宁德新能源科技有限公司 锂离子电池及其电解液
WO2012169570A1 (ja) * 2011-06-07 2012-12-13 住友軽金属工業株式会社 アルミニウム合金箔の製造方法およびアルミニウム合金箔
CN103003457A (zh) * 2010-07-16 2013-03-27 株式会社神户制钢所 电池集电体用铝硬质箔
CN104505535A (zh) * 2014-12-29 2015-04-08 珠海市赛纬电子材料有限公司 一种高电压锂离子电池的非水电解液
CN106340674A (zh) * 2016-11-29 2017-01-18 河南省法恩莱特新能源科技有限公司 一种三元过充电池用电解液
CN109461967A (zh) * 2018-11-01 2019-03-12 江西优锂新材股份有限公司 一种高镍三元正极材料动力锂离子电池电解液及制备方法
CN110611123A (zh) * 2019-10-23 2019-12-24 东莞维科电池有限公司 一种锂离子电池电解液和锂离子电池
CN110931868A (zh) * 2019-11-27 2020-03-27 惠州锂威新能源科技有限公司 一种非水电解液及含有该电解液的锂离子电池
CN111682264A (zh) * 2020-06-05 2020-09-18 惠州锂威新能源科技有限公司 电解液添加剂、电解液和锂离子电池
CN111900479A (zh) * 2020-08-21 2020-11-06 珠海冠宇电池股份有限公司 一种高温性能优异的锂离子电池

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102412417A (zh) * 2010-09-20 2012-04-11 华中科技大学 一种改善锂离子电池高温电化学性能的非水电解液及其应用
CN104900916A (zh) * 2015-06-26 2015-09-09 广州天赐高新材料股份有限公司 用于高容量锂离子电池的电解液、制备方法及锂离子电池
CN106505249B (zh) * 2016-12-15 2021-01-05 东莞市杉杉电池材料有限公司 一种锂离子电池电解液及含该电解液的锂离子电池
CN112310483B (zh) * 2019-07-30 2021-09-17 宁德时代新能源科技股份有限公司 一种锂离子电池
CN112467209A (zh) * 2019-09-09 2021-03-09 珠海冠宇电池股份有限公司 一种高低温性能兼顾的高电压锂离子电池

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004207117A (ja) * 2002-12-26 2004-07-22 Toyo Aluminium Kk 集電体用アルミニウム箔、集電体および二次電池
CN103003457A (zh) * 2010-07-16 2013-03-27 株式会社神户制钢所 电池集电体用铝硬质箔
WO2012169570A1 (ja) * 2011-06-07 2012-12-13 住友軽金属工業株式会社 アルミニウム合金箔の製造方法およびアルミニウム合金箔
CN102738511A (zh) * 2012-01-09 2012-10-17 宁德新能源科技有限公司 锂离子电池及其电解液
CN104505535A (zh) * 2014-12-29 2015-04-08 珠海市赛纬电子材料有限公司 一种高电压锂离子电池的非水电解液
CN106340674A (zh) * 2016-11-29 2017-01-18 河南省法恩莱特新能源科技有限公司 一种三元过充电池用电解液
CN109461967A (zh) * 2018-11-01 2019-03-12 江西优锂新材股份有限公司 一种高镍三元正极材料动力锂离子电池电解液及制备方法
CN110611123A (zh) * 2019-10-23 2019-12-24 东莞维科电池有限公司 一种锂离子电池电解液和锂离子电池
CN110931868A (zh) * 2019-11-27 2020-03-27 惠州锂威新能源科技有限公司 一种非水电解液及含有该电解液的锂离子电池
CN111682264A (zh) * 2020-06-05 2020-09-18 惠州锂威新能源科技有限公司 电解液添加剂、电解液和锂离子电池
CN111900479A (zh) * 2020-08-21 2020-11-06 珠海冠宇电池股份有限公司 一种高温性能优异的锂离子电池

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP4300651A4 *

Also Published As

Publication number Publication date
EP4300651A1 (en) 2024-01-03
CN114556662A (zh) 2022-05-27
EP4300651A4 (en) 2024-05-08
BR112023019937A2 (pt) 2024-02-06
US20240021878A1 (en) 2024-01-18

Similar Documents

Publication Publication Date Title
US11735771B2 (en) Electrolyte solution and electrochemical device using the same
US20220123363A1 (en) Electrolytic solution and electrochemical device using the same
CN111430793B (zh) 电解液及使用其的电化学装置和电子装置
JP2022547364A (ja) 電解液、並びに、電解液を含む電気化学装置及び電子装置
WO2021218267A1 (zh) 一种电解液及电化学装置
CN110518286B (zh) 电解液及包括电解液的电化学装置及电子装置
WO2023045487A1 (zh) 电化学装置和电子装置
WO2021120434A1 (zh) 一种电解液及电化学装置
CN111740147B (zh) 电解液和包含电解液的电化学装置
US11031630B2 (en) Electrolyte and electrochemical device
WO2021223181A1 (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
WO2021128206A1 (zh) 一种电解液及电化学装置
WO2021174421A1 (zh) 电解液和使用其的电化学装置
WO2021127993A1 (zh) 电解液以及使用其的电化学装置和电子装置
CN111697267A (zh) 电解液和包含电解液的电化学装置及电子装置
CN112103561B (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
CN111477964B (zh) 一种电解液及电化学装置
WO2021128203A1 (zh) 一种电解液及电化学装置
CN111740162A (zh) 电解液和包括电解液的电化学装置及电子装置
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
WO2022204980A1 (zh) 一种电解液及含有该电解液的电化学装置
CN113889664B (zh) 电解液、电化学装置和电子装置

Legal Events

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

Ref document number: 21933661

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 2021933661

Country of ref document: EP

REG Reference to national code

Ref country code: BR

Ref legal event code: B01A

Ref document number: 112023019937

Country of ref document: BR

ENP Entry into the national phase

Ref document number: 2021933661

Country of ref document: EP

Effective date: 20230926

NENP Non-entry into the national phase

Ref country code: DE

ENP Entry into the national phase

Ref document number: 112023019937

Country of ref document: BR

Kind code of ref document: A2

Effective date: 20230927