WO2021189255A1 - 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 PDFInfo
- Publication number
- WO2021189255A1 WO2021189255A1 PCT/CN2020/080914 CN2020080914W WO2021189255A1 WO 2021189255 A1 WO2021189255 A1 WO 2021189255A1 CN 2020080914 W CN2020080914 W CN 2020080914W WO 2021189255 A1 WO2021189255 A1 WO 2021189255A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- compound
- formula
- electrolyte
- lithium
- electrochemical device
- Prior art date
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
- H01M10/052—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
- H01M10/0567—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
- H01M10/42—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
- H01M2300/00—Electrolytes
- H01M2300/0017—Non-aqueous electrolytes
- H01M2300/0025—Organic electrolyte
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Definitions
- This application relates to the field of energy storage technology, and in particular to an electrolyte and an electrochemical device containing the electrolyte.
- Electrochemical devices for example, lithium-ion batteries
- higher requirements have been placed on the endurance of lithium-ion batteries.
- Increasing the charge cut-off voltage of lithium-ion batteries and increasing the amount of lithium removed from the positive electrode material are effective means to increase the energy density of lithium-ion batteries.
- the present invention provides an electrolyte and an electrochemical device comprising the electrolyte.
- the electrolyte contains a dicyclic sulfite compound and a polynitrile compound, which can form a stable protective layer on the surface of a positive electrode to ensure a lithium ion battery It can still run stably under ⁇ 4.45V.
- the electrolyte can significantly improve the high-voltage lithium-ion battery's high-temperature intermittent cycle capacity retention rate and high-temperature resistance safety performance after cycling.
- an electrolyte In some embodiments, the electrolyte includes:
- R 1 , R 2 , R 3 and R 4 are each independently selected from hydrogen, halogen, substituted or unsubstituted C 1 -C 7 alkyl, wherein when substituted, the substituent is halogen or cyano;
- a, d, f, h, j, k, l, and m are each independently selected from an integer of 1 to 5, and b, c, e, h, g, and i are each independently selected from an integer of 0 to 5.
- the compound of formula I includes at least one of the following compounds:
- the compound of formula II includes at least one of the following compounds:
- the compound of formula III includes at least one of the following compounds:
- the compound of formula IV includes at least one of the following compounds.
- the compound of formula V includes the following compounds:
- the amount of the compound of formula I accounts for 0.01% to 5% of the mass fraction of the electrolyte. In some embodiments, the total amount of the compound of formula II, compound of formula III, compound of formula IV or compound of formula V accounts for 0.01% to 10% of the mass fraction of the electrolyte.
- the amount of the compound of formula II accounts for 0.1% to 3% of the mass fraction of the electrolyte.
- the amount of the compound of formula III accounts for 0.1% to 3% of the mass fraction of the electrolyte.
- the amount of the compound of formula IV accounts for 0.1% to 7% of the mass fraction of the electrolyte.
- the amount of the compound of formula V accounts for 0.1% to 3% of the mass fraction of the electrolyte.
- the double cyclic sulfite is oxidized on the surface of the positive electrode to form a macromolecular positive electrode protective layer, but the protection is not dense enough; at the same time, the polynitrile additives are easy to form coordination with the transition metal elements on the positive electrode surface and combine with the two-linked ring
- the protective layer formed by sulfite can form a dense protective layer on the positive electrode, which can significantly inhibit the safety problems of flatulence, capacity decay and thermal failure caused by the side reaction of the electrolyte in the positive electrode at high temperature.
- the electrolyte further includes a salt-based additive
- the salt-based additive includes lithium difluorooxalate, lithium bisoxalate, lithium tetrafluoroborate, lithium difluorophosphate, lithium tetrafluorophosphate, and lithium tetrafluoroborate.
- the electrolyte further includes additive A, and the additive A includes at least one of fluoroethylene carbonate, ethylene carbonate, or 1,3-propane sultone, and the additive A
- the amount of the electrolyte accounts for 2% to 9% of the mass fraction of the electrolyte.
- the electrochemical device includes a positive electrode, a negative electrode, a separator, and any one of the foregoing electrolytes.
- the isolation film includes a polyolefin layer on which a protective layer is disposed;
- the protective layer includes boehmite, Al 2 O 3 , ZnO, SiO 2 , TiO 2 or ZrO 2 At least one of; the thickness of the protective layer is about 0.1 micrometers to about 3 micrometers.
- the protective layer further includes a polymer, the polymer including tetrafluoroethylene, vinylidene fluoride, hexafluoroethylene, perfluoroalkyl vinyl ether, ethylene, chlorotrifluoroethylene, At least one of homopolymers and copolymers of propylene, acrylic acid, methacrylic acid, itaconic acid, ethyl acrylate, butyl acrylate, acrylonitrile, methacrylonitrile, and the thickness of the polyolefin layer
- the thickness to ratio of the protective layer is about 1:1 to about 20:1.
- the negative active material includes a silicon-containing material and graphite, and the weight ratio of the silicon-containing material to the graphite is 5:95 to 50:50.
- Another aspect of the present invention provides an electronic device, which includes any one of the electrochemical devices described above.
- the term "about” is used to describe and illustrate small variations.
- 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 stated 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%.
- a list of items connected by the term "one of” may mean any one of the listed items. For example, if items A and B are listed, then the phrase “one of A and B” means only A or only B. In another example, if items A, B, and C are listed, then the phrase "one of A, B, and C" means only A; only B; or only C.
- Project A can contain a single element or multiple elements.
- Project B can contain a single element or multiple elements.
- Project C can contain a single element or multiple elements.
- a list of items connected by the term "at least one of” can mean any combination of the listed items. For example, if items A and B are listed, then the phrase “at least one of A and B" or “at least one of A or B” means only A; only B; or A and B. In another example, if items A, B, and C are listed, then the phrase “at least one of A, B, and C” or “at least one of A, B, or C” means 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 element or multiple elements.
- Project B can contain a single element or multiple elements.
- Project C can contain a single element or multiple elements.
- the number after the capital letter “C”, such as “C 1 -C 10 ", “C 3 -C 10 “, etc., after the "C” indicates the number of carbons in a specific functional group. That is, the functional groups may include 1-10 carbon atoms and 3-10 carbon atoms, respectively.
- C 1 -C 4 alkyl refers to an alkyl group having 1 to 4 carbon atoms, such as CH 3 -, CH 3 CH 2 -, CH 3 CH 2 CH 2 -, (CH 3 ) 2 CH- , CH 3 CH 2 CH 2 CH 2 -, CH 3 CH 2 CH(CH 3 )- or (CH 3 ) 3 C-.
- alkyl is expected to be a linear saturated hydrocarbon structure having 1 to 7 carbon atoms. "Alkyl” is also expected to be a branched or cyclic hydrocarbon structure having 3 to 7 carbon atoms.
- the alkyl group may be an alkyl group of 1 to 7 carbon atoms, or an alkyl group of 1 to 4 carbon atoms.
- butyl means to include n-butyl, sec-butyl, isobutyl, and 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.
- halogen encompasses F, Cl, Br, and I, preferably F or Cl.
- the aforementioned substituent may be substituted with one or more substituents selected from halogen or cyano.
- the content of each component in the electrolyte is based on the total weight of the electrolyte.
- electrolyte comprising:
- R 1 , R 2 , R 3 and R 4 are each independently selected from hydrogen, halogen, substituted or unsubstituted C 1 -C 7 alkyl, wherein when substituted, the substituent is halogen or cyano;
- a, d, f, h, j, k, l, and m are each independently selected from 1, 2, 3, 4, or 5; b, c, e, h, g, and i are each independently selected from 0, 1, 2 , 3, 4, or 5.
- R 1 , R 2 , R 3 and R 4 are each independently selected from hydrogen, halogen, substituted or unsubstituted C 1 -C 5 alkyl, wherein the substituent is halogen when substituted; wherein a, d, f, h, j, k, l, and m are each independently selected from 1, 2, 3, or 4; b, c, e, h, g, and i are each independently selected from 0, 1, 2, 3, or 4.
- R 1 , R 2 , R 3 and R 4 are each independently selected from hydrogen, fluorine, fluorine-substituted or unsubstituted C 1 -C 3 alkyl; wherein a, d, f, h, j, k, l, and m are each independently selected from 1, 2, or 3; b, c, e, h, g, and i are each independently selected from 0, 1, 2, or 3.
- R 1 , R 2 , R 3 and R 4 are each independently selected from hydrogen, fluorine, methyl, ethyl, or -CF 3 .
- the compound of formula I includes at least one of the following compounds:
- the compound of formula II includes at least one of the following compounds:
- the compound of formula III includes at least one of the following compounds:
- the compound of formula IV includes at least one of the following compounds:
- the compound of formula V includes the following compounds:
- the amount of the compound of formula I accounts for 0.01% to 5%, 0.1% to 4%, 0.1% to 3%, or 0.2% to 1% of the mass fraction of the electrolyte. In some embodiments, the amount of the compound of formula I accounts for about 0.05%, about 0.3%, about 0.4%, about 0.5%, about 0.6%, about 0.7%, about 0.8%, about 0.9%, About 1.0%, about 1.2%, about 1.4%, about 1.6%, about 1.8%, about 2.0%, about 2.5%, about 3.5%, or about 4.5%.
- the amount of the compound of formula II accounts for 0.1% to 3%, 0.1% to 2%, 0.3% to 2%, or 0.5% to 2% of the mass fraction of the electrolyte.
- the amount of the compound of formula III accounts for 0.1% to 3%, 0.1% to 2%, 0.3% to 2%, or 0.5% to 2% of the mass fraction of the electrolyte.
- the amount of the compound of formula IV accounts for 0.1% to 7%, 0.1% to 6%, 0.1% to 5%, 0.3% to 6%, 0.5% to 6% of the mass fraction of the electrolyte. %, or 1% to 5%.
- the amount of the compound of formula V accounts for 0.1% to 3%, 0.1% to 2%, 0.3% to 2%, or 0.5% to 2% of the mass fraction of the electrolyte.
- the amount of the compound of formula II, compound of formula III, compound of formula IV or compound of formula V accounts for 0.1% to 10%, 0.2% to 9%, 0.3% to 8% of the mass fraction of the electrolyte. %, 0.4% to 7%, 0.5% to 6%, 0.6% to 5%, or 0.7% to 4%. In some embodiments, the amount of the compound of formula II, compound of formula III, compound of formula IV or compound of formula V accounts for about 1%, about 1.5%, about 2%, about 2.5% of the mass fraction of the electrolyte. About 3%, about 3.5%, about 4%, about 4.5%, about 5.5%, about 6.5%, about 7.5%, about 8.5%, or about 9.5%.
- the electrolyte in order to further improve the secondary battery, it is also necessary to enhance the stability of the electrolyte, the electrolyte further contains salt additives, at least one of the compound of formula II, compound of formula III, compound of formula IV or compound of formula V
- the salt additives and the compound of formula I can improve the stability of the electrolyte, can inhibit the generation of acidic substances in the electrolyte, reduce the etching effect on the positive electrode interface protective layer, and improve the disulfite and polysulfite.
- the stability of the protective layer formed by the nitrile additives on the positive electrode enables the positive electrode interface to remain stable for a long time under high voltage.
- the salt additives include lithium difluorooxalate borate (LiDFOB), lithium bisoxalate borate (LiBOB), lithium tetrafluoroborate (LiBF 4 ), lithium difluorophosphate (LiPO 2 F 2 ), lithium tetrafluorophosphate (LiPOF 4) ), lithium tetrafluorooxalate phosphate, lithium difluorobisoxalate phosphate, sodium bisfluorosulfonimide (NaFSI), sodium bistrifluoromethanesulfonimide (NaTFSI), sodium hexafluorophosphate (NaPF 6 ), difluoro At least one of potassium sulfonimide (KFSI), potassium bistrifluoromethanesulfonimide (KTFSI), or potassium hexafluorophosphate (KPF 6 ).
- LiDFOB lithium difluorooxalate borate
- LiBOB lithium bisoxa
- the amount of the salt additive accounts for 0.001% to 2%, 0.01% to 1.8%, 0.05% to 1.6% of the mass fraction of the electrolyte; in some embodiments, the salt The amount of additives accounts for about 0.1%, about 0.2%, about 0.3%, about 0.4%, about 0.5%, about 0.6%, about 0.7%, about 0.8%, about 0.9%, about 1.0% of the mass fraction of the electrolyte. %, about 1.2%, or about 1.4%.
- the electrolyte further includes additive A, and the additive A includes fluoroethylene carbonate (FEC) and ethylene carbonate (VC). , Or at least one of 1,3-propane sultone (PS).
- FEC fluoroethylene carbonate
- VC ethylene carbonate
- PS 1,3-propane sultone
- the amount of the additive A accounts for 2% to 9% of the mass fraction of the electrolyte. In some embodiments, the amount of the additive A accounts for about 2.5%, about 3%, about 3.5%, about 4%, about 4.5%, about 5%, about 5.5%, about 6% of the mass fraction of the electrolyte. %, about 6.5%, about 7%, about 7.5%, about 8%, or about 8.5%.
- the electrolyte further includes a lithium salt and an organic solvent.
- the lithium salt is selected from one or more of inorganic lithium salt and organic lithium salt.
- the lithium salt contains at least one of fluorine, boron, or phosphorus.
- the lithium salt is selected from one or more of the following lithium salts: lithium hexafluorophosphate (abbreviated as LiPF 6 ), lithium bistrifluoromethanesulfonimide (abbreviated as LiTFSI), bis(fluorosulfonyl) Lithium imide (LiFSI in short), lithium hexafluoroarsenate (LiAsF 6 in short), lithium perchlorate (LiClO 4 in short), or lithium trifluoromethanesulfonate (LiCF 3 SO 3 in short).
- LiPF 6 lithium hexafluorophosphate
- LiTFSI lithium bistrifluoromethanesulfonimide
- LiFSI bis(fluorosulfonyl) Lithium imide
- the concentration of the lithium salt is 0.5 mol/L to 1.5 mol/L. In some embodiments, the concentration of the lithium salt is 0.8 mol/L to 1.2 mol/L. In some embodiments, the concentration of the lithium salt is 0.9 mol/L to 1.1 mol/L.
- the solvent includes a cyclic ester and a chain ester, wherein the cyclic ester is selected from at least one of ethylene carbonate (EC), propylene carbonate (PC), ⁇ -butyrolactone (BL), and butylene carbonate Species; chain ester selected from dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), propyl ethyl carbonate, methyl formate (MF), ethyl formate (abbreviated as MA ), ethyl acetate (EA), ethyl propionate (abbreviated as EP), propyl propionate (abbreviated as PP), methyl propionate, methyl butyrate, ethyl butyrate, fluoromethyl ethyl carbonate , Fluorodimethyl carbonate, fluorodiethyl carbonate, fluoropropionate, fluoropropionate, fluoropropionate,
- the solvent accounts for about 70% to about 95% of the weight of the electrolyte.
- the electrochemical device of the present application includes 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 is an electrochemical device having a positive electrode having a positive electrode active material capable of occluding and releasing metal ions, and a negative electrode having a negative electrode active material capable of occluding and releasing metal ions. Its characteristics are It consists of any of the above-mentioned electrolytes of the present 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, 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 can 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 active material includes a silicon-containing material, and the silicon-containing material includes SiO x , silicon simple substance, or a mixture of the two, where 0.5 ⁇ x ⁇ 1.5.
- 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, polymers containing ethylene oxide, 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 substrate, 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 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 cobalt oxide (LiCoO 2 ), lithium nickel cobalt manganese (NCM) ternary material, lithium iron phosphate (LiFePO 4 ), lithium manganate (LiMn 2 O 4 ), or their Any combination of.
- 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.
- 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, or any of them. combination.
- 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, 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 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 release film may include a substrate layer and a coating.
- 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, and the weight average molecular weight is different; when the substrate layer is multiple layers , The closed cell temperature of the polymer of different substrate layers is different.
- At least one surface of the substrate layer of the present application is provided with a coating.
- the coating may be a polymer layer or an inorganic layer, or a layer formed by a mixed polymer and an inorganic substance.
- the thickness of the coating is between 0.1 micrometers to 4 micrometers, 0.4 micrometers to 3.5 micrometers, 0.8 micrometers to 3 micrometers, or 1.2 micrometers to 3 micrometers.
- the isolation film includes a polyolefin layer, and a protective layer is provided on the polyolefin layer; these protective layers can prevent the polymer isolation film from directly contacting the positive electrode, and prevent the high voltage positive electrode from contacting the polymer isolation film.
- the protective layer contains at least one of boehmite, Al 2 O 3 , ZnO, SiO 2 , TiO 2 or ZrO 2 ; the thickness of the protective layer is 0.1 ⁇ m to 3 ⁇ m.
- the protective layer further includes a polymer, the polymer including tetrafluoroethylene, vinylidene fluoride, hexafluoropropylene, perfluoroalkyl vinyl ether, ethylene, chlorotrifluoroethylene, At least one of propylene, acrylic acid, methacrylic acid, itaconic acid, ethyl acrylate, butyl acrylate, acrylonitrile, methacrylonitrile homopolymer and copolymers thereof.
- a polymer including tetrafluoroethylene, vinylidene fluoride, hexafluoropropylene, perfluoroalkyl vinyl ether, ethylene, chlorotrifluoroethylene, At least one of propylene, acrylic acid, methacrylic acid, itaconic acid, ethyl acrylate, butyl acrylate, acrylonitrile, methacrylonitrile homopolymer and copolymers thereof.
- the ratio of the thickness of the polyolefin layer to the thickness of the protective layer is 1:1 to 20:1. In some embodiments, the thickness of the polyolefin layer is relative to the thickness of the protective layer. The ratio is about 2:1, about 3:1, about 4:1, about 5:1, about 6:1, about 7:1, about 8:1, about 9:1, about 10:1, about 12: 1. About 14:1, about 16:1, or about 18:1.
- the isolation membrane comprises a polyethylene porous isolation membrane with a thickness of about 7 microns, and one side of the isolation membrane is coated with a coating about 1.5 microns thick, and the coating contains Al 2 O 3 and poly Vinyl fluoride (PVDF).
- PVDF poly Vinyl fluoride
- a stable protective layer can be formed on the surface of the positive and negative materials to ensure the stable charging and discharging of the lithium-ion battery at a high voltage of ⁇ 4.45V, which is suitable for use in electronic equipment containing electrochemical devices. middle.
- the use of the electrochemical device of the present application is not particularly limited, and it can be used for various well-known uses.
- notebook computers pen-input computers, mobile computers, e-book players, portable phones, portable fax machines, portable copiers, portable printers, headsets, video recorders, LCD TVs, portable cleaners, portable CD players, Mini discs, transceivers, electronic notebooks, calculators, memory cards, portable recorders, radios, backup power supplies, motors, cars, motorcycles, assisted bicycles, bicycles, lighting equipment, toys, game consoles, clocks, power tools, flashlights , Cameras, large household storage batteries or lithium-ion capacitors, etc.
- LiCoO 2 lithium cobalt oxide
- conductive carbon conductive carbon
- PVDF binder polyvinylidene fluoride
- NMP N-methylpyrrolidone
- EC ethylene carbonate
- PC propylene carbonate
- DEC diethyl carbonate
- EP ethyl propionate
- Specific types and amounts of substances are added to the above electrolyte (the types and amounts of the added substances are shown in Table 1, and the content of each substance is calculated based on the total weight of the electrolyte), and the electrolyte is obtained after uniform mixing.
- the concentration of LiPF 6 in the electrolyte is 1.05 mol/L.
- a polyethylene porous isolation membrane with a thickness of 7 ⁇ m is selected, and one side of the isolation membrane is coated with a 1.5 ⁇ m-thick coating containing Al 2 O 3 and polyvinylidene fluoride (PVDF).
- PVDF polyvinylidene fluoride
- the size of the obtained lithium ion battery was 3.3 mm ⁇ 39 mm ⁇ 96 mm.
- the electrolytes and lithium ion batteries of Examples 1 to 24 and Comparative Examples 1 to 2 were prepared according to the above methods (1) to (5).
- Example 25 and Comparative Examples 3 to 4 were prepared, in which the negative electrode was prepared according to the following method, and the others were prepared according to the above methods (2) to (5).
- the negative electrode active material graphite the negative electrode active material silicon oxide material (SiO x , 0.5 ⁇ x ⁇ 1.5), the binder styrene butadiene rubber (SBR), the thickener sodium carboxymethyl cellulose (CMC) according to the weight ratio of 87 :10:2:1 Disperse in an appropriate amount of water, stir and mix well; coat the negative electrode slurry on the copper foil of the negative electrode current collector of 8 microns, and then bake it at 120°C for 1 hour, and then undergo compaction and slitting , Weld the tabs to obtain the negative electrode.
- the negative electrode active material silicon oxide material SiO x , 0.5 ⁇ x ⁇ 1.5
- SBR binder styrene butadiene rubber
- CMC thickener sodium carboxymethyl cellulose
- Example 26 to Example 27 were prepared according to the following methods, and others were prepared according to the above-mentioned methods (1)-(3) and (5):
- a polyethylene porous isolation membrane with a thickness of 7 microns is selected, and one side of the isolation membrane is coated with a 1.5-micron thick coating containing boehmite and polyvinylidene fluoride (PVDF).
- PVDF polyvinylidene fluoride
- Example 28 to Example 29 were prepared according to the following methods, and others were prepared according to the above-mentioned methods (1)-(3) and (5):
- a 7-micron thick polyethylene porous isolation membrane is selected, and one side of the isolation membrane is coated with a 1.0-micron thick coating containing boehmite and polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP).
- PVDF-HFP polyvinylidene fluoride-hexafluoropropylene copolymer
- Battery capacity retention rate at the Nth cycle battery discharge capacity at the Nth cycle/battery initial discharge capacity ⁇ 100%
- Battery size test Take three batteries from each of Example 1 and Example 22, charge them to 3.9V at a constant current of 0.5C at 25°C, and then charge to 0.05C at a constant voltage to cut off; use a micrometer to test the thickness and width of the battery ,length;
- Energy density (Wh/L) discharge energy (Wh)/(battery thickness mm ⁇ battery width mm ⁇ battery length mm ⁇ 10 -6 )
- Example 1 and Comparative Examples 1 and 2 According to the comparison between Example 1 and Comparative Examples 1 and 2, and the comparison between Example 25 and Comparative Examples 3 and 4, it can be seen that the compound of formula I (for example, compound 1) and the compound of formula III (for example, compound 7) It can significantly improve the intermittent cycle performance and high temperature safety performance of lithium-ion batteries.
- Example 1 According to the test results of Example 1 and Examples 5 to 6, it can be seen that the combination of each example of the compound of formula I (such as compounds 1, 2, and 3) and the compound of formula III (such as compound 7) can be added to the electrolyte. Similar technical effects.
- Example 1 According to the test results of Example 1 and Examples 7 to 11 and Comparative Example 2, it can be seen that an appropriate amount of the compound of formula I (for example compound 1) is added to the electrolyte while adding a range of about 0.1% to about 10% of the compound of formula III (for example, compound 7) significantly improves the capacity retention rate and high temperature resistance safety performance of the lithium ion battery; the added formula III compound accounts for 0.5% to 6% of the electrolyte solution, and the effect is particularly ideal.
- the compound of formula I for example compound 1
- compound 7 significantly improves the capacity retention rate and high temperature resistance safety performance of the lithium ion battery
- the added formula III compound accounts for 0.5% to 6% of the electrolyte solution, and the effect is particularly ideal.
- Example 1 According to the test results of Example 1 and Examples 12 to 15, it can be seen that the compound of formula III (for example compound 7), the compound of formula II (for example compound 13), the compound of formula IV (for example compound 18) or the compound of formula V (for example compound 20) Or their combination can be added to the electrolyte together with the compound of formula I (for example compound 1) to obtain similar technical effects.
- the compound of formula III for example compound 7
- the compound of formula II for example compound 13
- the compound of formula IV for example compound 18
- the compound of formula V for example compound 20
- Example 1 According to the test results of Example 1 and Examples 16 to 19, it can be seen that the electrolyte solution of adding the compound of formula I (such as compound 1) and formula III (such as compound 7) is further added with an appropriate amount of salt additives (such as LiDFOB, LiPO 2 F 2 ). Or at least one of NaPF 6 ), so that the capacity retention rate and high temperature resistance safety performance of the lithium ion battery at high temperatures are further improved.
- salt additives such as LiDFOB, LiPO 2 F 2 .
- NaPF 6 NaPF 6
- Example 1 According to the test results of Example 1 and Examples 20 to 22, it can be seen that the electrolyte solution of adding the compound of formula I (such as compound 1) and formula III (such as compound 7) is further added with an appropriate amount of additive A (such as at least one of FEC or PS). ), so that the capacity retention rate and high-temperature safety performance of the lithium-ion battery at high temperatures are further improved.
- additive A such as at least one of FEC or PS
- Example 16 and Example 23 it can be seen that the electrolyte solution with the compound of formula I (for example compound 1), formula III (for example compound 7) and salt additives (for example LiDFOB) is further added with an appropriate amount of additive A (for example At least one of FEC or PS), so that the capacity retention rate and high temperature resistance safety performance of the lithium ion battery at high temperatures are further improved.
- additive A for example At least one of FEC or PS
- Example 25 uses a negative electrode containing graphite and silicon-oxygen materials, and Example 1 uses a graphite negative electrode, and both have the same positive electrode material.
- the gram capacity of graphite anode is much lower than that of silicon-oxygen materials. Therefore, the loading capacity of Example 25 (graphite and silicon oxide negative electrode) is lower than that of Example 1 (graphite negative electrode).
- the battery obtained in Example 25 has a smaller volume, and its energy density is higher than that in Example 1.
- Example 25 Based on the experimental results of Example 1 and Example 25, it can be seen that whether it is a lithium battery containing a graphite negative electrode or a lithium ion battery containing a silicon-oxygen material negative electrode, the electrolyte of the present invention can obtain a significantly improved capacity retention rate at high temperatures. And high-temperature safety performance, the improvement effect is particularly significant for lithium batteries containing graphite anodes.
- Example 26 to Example 29 show that the use of a specific isolation membrane can maintain a better capacity retention rate while improving the thermal failure of the battery.
- the electrolyte provided by the present invention can form a stable protective layer on the surface of the positive and negative materials, and ensure the stable charging and discharging operation of the lithium ion battery at a high voltage of ⁇ 4.45V.
- the lithium ion secondary battery provided by the present invention can operate well under high energy density and charge cut-off voltage ⁇ 4.45V, and has superior high-temperature intermittent cycle capacity retention rate and high-temperature resistance safety performance after cycling.
- 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 “exemplary”, 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)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Inorganic Chemistry (AREA)
- Materials Engineering (AREA)
- Secondary Cells (AREA)
Abstract
本申请提供了一种电解液及电化学装置。本申请的电解液含有二联环状亚硫酸酯化合物与多腈化合物,能在正极表面形成稳定的保护层,保证锂离子电池在≥4.45V下仍能稳定的运行,该电解液能显著改善高电压锂离子电池高温间歇循环容量保持率及循环后耐高温安全性能。
Description
本申请涉及储能技术领域,尤其涉及一种电解液和包含该电解液的电化学装置。
电化学装置(例如,锂离子电池)有能量密度高,工作电压高、自放电率低、循环寿命长、无污染等优点,现已作为电源广泛应用于相机、手机、无人机、笔记本电脑、智能手表等电子产品。近年来,随着智能电子产品的快速发展,对锂离子电池的续航能力有了更高的要求。提升锂离子电池的充电截止电压,提高正极材料的脱锂量,是有效提高锂离子电池能量密度的手段。目前,4.4V高电压锂离子电池产品已广泛应用,进一步提高充电截止电压至4.45V甚至大于4.5V的高电压体系是各大科研单位、电池制造企业研究的热点。然而,提高充电截止电压也会带来许多问题,例如高电压下正极与电解液反应活性增强,电池容易胀气,高温下循环容量衰减加速等。如何解决上述高能量密度高电压锂离子电池存在的问题以提高电池的续航能力已成为本领域的重要课题。
发明内容
本发明提供了一种电解液和包括该电解液的电化学装置,所述电解液含有二联环状亚硫酸酯化合物与多腈化合物,能在正极表面形成稳定的保护层,保证锂离子电池在≥4.45V下仍能稳定的运行,该电解液能显著改善高电压锂离子电池高温间歇循环容量保持率及循环后耐高温安全性能。
本发明的一方面提供了一种电解液。在一些实施例中,所述电解液包含:
式I化合物,以及
式II化合物、式III化合物、式IV化合物或式V化合物中的至少一种;
其中,R
1、R
2、R
3和R
4各自独立选自氢、卤素、经取代或未经取代的C
1-C
7烷基,其中经取代时取代基为卤素或氰基;
其中a、d、f、h、j、k、l和m各自独立选自1至5的整数,b、c、e、h、g和i各自独立选自0至5的整数。
在一些实施例中,所述式I化合物包含下述化合物中的至少一种:
在一些实施例中,所述式II化合物包含下述化合物中的至少一种:
在一些实施例中,所述式III化合物包含下述化合物中的至少一种:
在一些实施例中,所述式IV化合物包含下述化合物中的至少一种。
在一些实施例中,所述式V化合物包含下述化合物:
在一些实施例中,其中所述式I化合物的量占所述电解液的质量分数为0.01%至5%。在一些实施例中,所述式II化合物、式III化合物、式IV化合物或式V化合物的总量占所述电解液的质量分数为0.01%至10%。
在一些实施例中,所述式II化合物的量占所述电解液的质量分数为0.1%至3%。
在一些实施例中,所述式III化合物的量占所述电解液的质量分数为0.1%至3%。
在一些实施例中,所述式IV化合物的量占所述电解液的质量分数为0.1%至7%。
在一些实施例中,所述式V化合物的量占所述电解液的质量分数为0.1%至3%。
%%
高电压下,二联环状亚硫酸酯在正极表面发生氧化形成大分子正极保护层,但保护不够致密;同时,多腈类添加剂易与正极表面过渡金属元素形成配位,结合二联环状亚硫酸酯形成的保护层,可在正极形成致密的保护层,显著的抑制高温下电解液在正极的 副反应造成的胀气、容量衰减和热失效安全问题。
在一些实施例中,所述电解液进一步包含盐类添加剂,所述盐类添加剂包含二氟草酸硼酸锂、双草酸硼酸锂、四氟硼酸锂、二氟磷酸锂、四氟磷酸锂、四氟草酸磷酸锂、二氟双草酸磷酸锂、双氟磺酰亚胺钠、双三氟甲烷磺酰亚胺钠、六氟磷酸钠、双氟磺酰亚胺钾、双三氟甲烷磺酰亚胺钾或六氟磷酸钾中的至少一种;所述盐类添加剂的量占所述电解液的质量分数为0.001%至2%。
在一些实施例中,所述电解液进一步包含添加剂A,所述添加剂A包含氟代碳酸乙烯酯、碳酸亚乙酯、或1,3-丙烷磺内酯中的至少一种,所述添加剂A的量占所述电解液质量分数的2%至9%。
本发明的另一方面提供了一种电化学装置。所述电化学装置包括正极、负极、隔离膜以及上述任意一种电解液。
在一些实施例中,所述隔离膜包含聚烯烃层,所述聚烯烃层上设置有保护层;所述保护层含有勃姆石、Al
2O
3、ZnO、SiO
2、TiO
2或ZrO
2中的至少一种;所述保护层的厚度为约0.1微米至约3微米。
在一些实施例中,其中所述保护层上还包含有聚合物,所述聚合物包括四氟乙烯、偏氟乙烯、六氟乙烯、全氟烷基乙烯基醚、乙烯、三氟氯乙烯、丙烯、丙烯酸、甲基丙烯酸、衣康酸、丙烯酸乙酯、丙烯酸丁酯、丙烯腈、甲基丙烯腈的均聚物及其共聚物中的至少一种,所述聚烯烃层的厚度与所述保护层的厚度至比为约1∶1至约20∶1。
在一些实施例中,其中所述负极包含负极活性材料,所述负极活性材料包含含硅材料和石墨,所述含硅材料与所述石墨的重量比为5∶95至50∶50。
本发明的又一方面提供了一种电子装置,所述电子装置包括如上所述的任意一种电化学装置。
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。
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要求保护范围的限制。除非另外明确指明,本文使用的下述术语具有下文指出的含义。
如本文中所使用,术语“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,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%。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“中的一者”连接的项目的列表可意味着所列项目中的任一者。例如,如果列出项目A及B,那么短语“A及B中的一者”意味着仅A或仅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中的一者”意味着仅A;仅B;或仅C。项目A可包含单个元件或多个元件。项目B可包含单个元件或多个元件。项目C可包含单个元件或多个元件。
在具体实施方式及权利要求书中,由术语“中的至少一者”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”或“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”或“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可包含单个元件或多个元件。项目B可包含单个元件或多个元件。项目C可包含单个元件或多个元件。
在具体实施方式及权利要求书中,在关于碳数的表述即大写字母“C”后面的数字,例如“C
1-C
10”、“C
3-C
10”等中,在“C”之后的数字例如“1”、“3”或“10”表示具体官能团中的碳数。即,官能团分别可包括1-10个碳原子和3-10个碳原子。例如,“C
1-C
4烷基”是指具有1-4个碳原子的烷基,例如CH
3-、CH
3CH
2-、CH
3CH
2CH
2-、(CH
3)
2CH-、CH
3CH
2CH
2CH
2-、CH
3CH
2CH(CH
3)-或(CH
3)
3C-。
如本文所用,术语“烷基”预期是具有1至7个碳原子的直链饱和烃结构。“烷基”还预期是具有3至7个碳原子的支链或环状烃结构。例如,烷基可为1~7个碳原子的烷基、或1~4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。
如本文所用,术语“卤素”涵盖F、Cl、Br及I,优选F或Cl。
当上述取代基经取代时,上述取代基可经一个或多个选自卤素或氰基的取代基取代。
如本文中所使用,电解液中各组分的含量均为基于电解液的总重量得到的。
一、电解液
本发明的一些实施例提供了一种电解液,所述电解液包含:
式I化合物,以及
式II化合物、式III化合物、式IV化合物或式V化合物中的至少一种;
其中,R
1、R
2、R
3和R
4各自独立选自氢、卤素、经取代或未经取代的C
1-C
7烷基,其中经取代时取代基为卤素或氰基;
其中a、d、f、h、j、k、l和m各自独立选自1、2、3、4或5;b、c、e、h、g和i各自独立选自0、1、2、3、4或5。
在一些实施例中,R
1、R
2、R
3和R
4各自独立选自氢、卤素、经取代或未经取代的C
1-C
5烷基,其中经取代时取代基为卤素;其中a、d、f、h、j、k、l和m各自独立选自1、2、3或4;b、c、e、h、g和i各自独立选自0、1、2、3或4。
在一些实施例中,R
1、R
2、R
3和R
4各自独立选自氢、氟、经氟取代或未经取代的C
1-C
3烷基;其中a、d、f、h、j、k、l和m各自独立选自1、2或3;b、c、e、h、g和i各自独立选自0、1、2或3。
在一些实施例中,R
1、R
2、R
3及R
4各自独立选自氢,氟,甲基、乙基、或-CF
3。
在一些实施例中,所述式I化合物包含下述化合物中的至少一种:
在一些实施例中,所述式II化合物包含下述化合物中的至少一种:
在一些实施例中,所述式III化合物包含下述化合物中的至少一种:
在一些实施例中,所述式IV化合物包含下述化合物中的至少一种:
在一些实施例中,所述式V化合物包含下述化合物:
在一些实施例中,所述式I化合物的量占所述电解液的质量分数为0.01%至5%、0.1%至4%、0.1%至3%、或0.2%至1%。在一些实施例中,式I化合物的量占所述电解液重量的约0.05%、约0.3%、约0.4%、约0.5%、约0.6%、约0.7%、约0.8%、约0.9%、约1.0%、约1.2%、约1.4%、约1.6%、约1.8%、约2.0%、约2.5%、约3.5%、或约4.5%。
在一些实施例中,所述式II化合物的量占所述电解液的质量分数为0.1%至3%、0.1%至2%、0.3%至2%、或0.5%至2%。
在一些实施例中,所述式III化合物的量占所述电解液的质量分数为0.1%至3%、0.1%至2%、0.3%至2%、或0.5%至2%。
在一些实施例中,所述式IV化合物的量占所述电解液的质量分数为0.1%至7%、0.1%至6%、0.1%至5%、0.3%至6%、0.5%至6%、或1%至5%。
在一些实施例中,所述式V化合物的量占所述电解液的质量分数为0.1%至3%、0.1%至2%、0.3%至2%、或0.5%至2%。
在一些实施例中,所述式II化合物、式III化合物、式IV化合物或式V化合物的量占所述电解液的质量分数为0.1%至10%、0.2%至9%、0.3%至8%、0.4%至7%、0.5%至6%、0.6%至5%、或0.7%至4%。在一些实施例中,所述式II化合物、式III化合物、式IV化合物或式V化合物的量占所述电解液的质量分数为约1%、约1.5%、约2%、约2.5%、约3%、约3.5%、约4%、约4.5%、约5.5%、约6.5%、约7.5%、约8.5%、或约9.5%。
在一些实施例中,为进一步改善二次电池,还需要加强电解液的稳定性,所述电解液进一步包含盐类添加剂,式II化合物、式III化合物、式IV化合物或式V化合物中的至少一种、盐类添加剂、式I化合物共同作用对电解液稳定性有较好提升,能抑制电解液酸性物质产生,减少对正极界面保护层的刻蚀作用,从而改善二联亚硫酸酯和多腈类添加剂在正极形成的保护层的稳定性,使得正极界面在高电压下能长时间保持稳定。所述盐类添加剂包含二氟草酸硼酸锂(LiDFOB)、双草酸硼酸锂(LiBOB)、四氟硼酸锂(LiBF
4)、二氟磷酸锂(LiPO
2F
2)、四氟磷酸锂(LiPOF
4)、四氟草酸磷酸锂、二氟双草酸磷 酸锂、双氟磺酰亚胺钠(NaFSI)、双三氟甲烷磺酰亚胺钠(NaTFSI)、六氟磷酸钠(NaPF
6)、双氟磺酰亚胺钾(KFSI)、双三氟甲烷磺酰亚胺钾(KTFSI)或六氟磷酸钾(KPF
6)中的至少一种。
在一些实施例中,所述盐类添加剂的量占所述电解液的质量分数为0.001%至2%、0.01%至1.8%、0.05%至1.6%;在一些实施例中,所述盐类添加剂的量占所述电解液的质量分数为约0.1%、约0.2%、约0.3%、约0.4%、约0.5%、约0.6%、约0.7%、约0.8%、约0.9%、约1.0%、约1.2%、或约1.4%。
在一些实施例中,为进一步改进高能量密度二次电池的循环稳定性,所述电解液进一步包含添加剂A,所述添加剂A包含氟代碳酸乙烯酯(FEC),碳酸亚乙酯(VC),或1,3-丙烷磺内酯(PS)中的至少一种。
在一些实施例中,所述添加剂A的量占所述电解液质量分数的2%至9%。在一些实施例中,所述添加剂A的量占所述电解液质量分数的约2.5%、约3%、约3.5%、约4%、约4.5%、约5%、约5.5%、约6%、约6.5%、约7%、约7.5%、约8%、或约8.5%。
在一些实施例中,所述电解液进一步包括锂盐和有机溶剂。
在一些实施例中,所述锂盐选自无机锂盐和有机锂盐中的一种或多种。在一些实施例中,所述锂盐含有氟元素、硼元素或磷元素中的至少一种。在一些实施例中,所述锂盐选自如下锂盐中的一种或多种:六氟磷酸锂(简写为LiPF
6)、双三氟甲烷磺酰亚胺锂(简写为LiTFSI)、双(氟磺酰)亚胺锂(简写为LiFSI)、六氟砷酸锂(简写为LiAsF
6)、高氯酸锂(简写为LiClO
4)、或三氟甲磺酸锂(简写为LiCF
3SO
3)。
在一些实施例中,所述锂盐的浓度为0.5mol/L至1.5mol/L。在一些实施例中,所述锂盐的浓度为0.8mol/L至1.2mol/L。在一些实施例中,所述锂盐的浓度为0.9mol/L至1.1mol/L。
所述的溶剂包含环状酯和链状酯,其中环状酯选自碳酸乙烯酯(EC)、碳酸丙烯酯(PC)、γ-丁内酯(BL)、碳酸丁烯酯中的至少一种;链状酯选自碳酸二甲酯(DMC)、碳酸二乙酯(DEC)、碳酸甲乙酯(EMC)、碳酸丙乙酯、甲酸甲酯(MF)、甲酸乙酯(简写为MA)、乙酸乙酯(EA)、丙酸乙酯(简写为EP)、丙酸丙酯(简写为PP)、丙酸甲酯、丁酸甲酯、丁酸乙酯、氟代碳酸甲乙酯、氟代碳酸二甲酯、氟代碳酸二乙酯、 氟代丙酸乙酯、氟代丙酸丙酯、氟代丙酸甲酯、氟代乙酸乙酯、氟代乙酸甲酯、氟代乙酸丙酯等中的至少一种。
在一些实施例中,其中所述溶剂占所述电解液重量的约70%至约95%。
二、电化学装置
本申请的电化学装置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是具备具有能够吸留、放出金属离子的正极活性物质的正极以及具有能够吸留、放出金属离子的负极活性物质的负极的电化学装置,其特征在于,包含本申请的上述任何电解液。
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。
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。在一些实施例中,负极活性材料包括含硅材料,所述含硅材料包含SiO
x、硅单质或二者的混合物,其中0.5<x<1.5。
当负极包括碳材料和硅材料时,基于负极活性材料总重量,碳材料:硅材料的比值为约95∶5至约50∶50、约90∶10至约60∶40、约85∶15至约70∶30、约80∶20至约75∶25。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%-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。
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,正极活性材料选自钴酸锂(LiCoO
2)、锂镍钴锰(NCM)三元材料、磷酸亚铁锂(LiFePO
4)、锰酸锂(LiMn
2O
4)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或它们的任意组合。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。
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涂层。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,重均分子量不同;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,本申请的基材层的至少一个表面上设置有涂层,涂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。所述涂层的厚度介于0.1微米至4微米、0.4微米至3.5微米、0.8微米至3微米、或1.2微米至3微米。
在一些实施例中,所述隔离膜包含聚烯烃层,所述聚烯烃层上设置有保护层;这些保护层能避免聚合物隔离膜直接与正极接触,防止高电压正极对聚合物隔离膜的氧化破 坏作用,所述保护层含有勃姆石、Al
2O
3、ZnO、SiO
2、TiO
2或ZrO
2中的至少一种;所述保护层的厚度为0.1微米至3微米。
在一些实施例中,其中所述保护层上还包含有聚合物,所述聚合物包括四氟乙烯、偏氟乙烯、六氟丙烯、全氟烷基乙烯基醚、乙烯、三氟氯乙烯、丙烯、丙烯酸、甲基丙烯酸、衣康酸、丙烯酸乙酯、丙烯酸丁酯、丙烯腈、甲基丙烯腈的均聚物及其共聚物中的至少一种。
在一些实施例中,所述聚烯烃层的厚度与所述保护层的厚度比为1∶1至20∶1、在一些实施例中,所述聚烯烃层的厚度与所述保护层的厚度比为约2∶1、约3∶1、约4∶1、约5∶1、约6∶1、约7∶1、约8∶1、约9∶1、约10∶1、约12∶1、约14∶1、约16∶1、或约18∶1。
在一些实施例中,所述隔离膜包含厚度为约7微米的聚乙烯多孔隔离膜,所述隔离膜一侧涂覆约1.5微米厚的涂层,该涂层含有Al
2O
3和聚偏氟乙烯(PVDF)。
三、应用
根据本申请实施例的电解液,能够在正负极材料表面形成稳定的保护层,保证锂离子电池在在≥4.45V的高电压下稳定充放电工作,适合使用在包含电化学装置的电子设备中。
本申请的电化学装置的用途没有特别限定,可以用于公知的各种用途。例如笔记本电脑、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、家庭用大型蓄电池或锂离子电容器等。
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)负极的制备
称取负极活性物质石墨、粘结剂丁苯橡胶(SBR)、增稠剂羧甲基纤维素钠(CMC)按重量比97∶2∶1分散于适量的水中,充分搅拌混合均匀;将负极浆料涂覆在8微米的负极集流体铜箔上,然后在120℃烘烤1小时形成负极活性材料层,之后经过压实、分切、焊接极耳,得到负极。
(2)正极的制备
称取正极活性物质钴酸锂(LiCoO
2)、导电碳、粘结剂聚偏氟乙烯(PVDF)按重量比97∶1.5∶1.5分散于适量的N-甲基吡咯烷酮(NMP)中,充分搅拌混合均匀;将正极浆料涂覆在10微米的正极集流体铝箔上,然后在120℃烘烤1小时形成正极活性材料层,之后经过压实、分切、焊接极耳,得到正极。
(3)电解液的制备
在干燥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)、丙酸乙酯(EP)按照质量比30∶10∶30∶30混合,之后加入LiPF
6作为锂盐。在上述电解液中加入特定种类和量的物质(添加物质的种类和量如表1所示,各物质的含量为基于电解液的总重量计算得到),混合均匀后获得电解液。电解液中LiPF
6的浓度为1.05mol/L。
(4)隔离膜的制备
选用7微米厚的聚乙烯多孔隔离膜,隔离膜一侧涂覆1.5微米厚的涂层,该涂层含有Al
2O
3和聚偏氟乙烯(PVDF)。
(5)锂离子电池的制备
将上述正极、隔离膜和负极按顺序叠好,使隔离膜处于正极和负极中间,然后卷绕、置于铝箔包装袋中,在80℃烘烤除水后,注入电解液、密封、化成、排气并测试容量得到成品的锂离子二次电池。得到的锂离子电池的尺寸为3.3mm×39mm×96mm。
实施例1至实施例24及对比例1至对比例2
按照上述方法(1)至(5)制备实施例1至24和对比例1至2的电解液以及锂离子电池。
实施例25及对比例3至4
制备实施例25和对比例3至4的电解液以及锂离子电池,其中负极按照下述方法制备,其它按照上述方法(2)至(5)制备。
称取负极活性物质石墨、负极活性物质硅氧材料(SiO
x,0.5<x<1.5)、粘结剂丁苯橡胶(SBR)、增稠剂羧甲基纤维素钠(CMC)按重量比87∶10∶2∶1分散于适量的水中,充分搅拌混合均匀;将负极浆料涂覆在8微米的负极集流体铜箔上,然后在120℃烘烤1小时,之后经过压实、分切、焊接极耳,得到负极。
实施例26至实施例27
实施例26至实施例27的隔离膜按照如下方法制备,其他按照上述方法(1)-(3)和(5)制备:
选用7微米厚的聚乙烯多孔隔离膜,隔离膜一侧涂覆1.5微米厚的涂层,该涂层含有勃姆石和聚偏氟乙烯(PVDF)。
实施例28至实施例29
实施例28至实施例29的隔离膜按照如下方法制备,其他按照上述方法(1)-(3)和(5)制备:
选用7微米厚的聚乙烯多孔隔离膜,隔离膜一侧涂覆1.0微米厚的涂层,该涂层含有勃姆石和聚偏氟乙烯-六氟丙烯共聚物(PVDF-HFP)。
表1实施例和对比例
其中“/”表示未添加该物质。
2.锂离子电池的循环性能测试
(1)45℃间歇循环测试
在45℃下,以0.5C恒电流充电至4.45V,然后在恒电压下充电至0.05C截止;在45℃下搁置20h;然后以0.5C恒电流放电至3.0V;重复100次,记录电池的容量保持率。
电池的第N次循环容量保持率=电池第N次循环放电容量/电池初始放电容量×100%
(2)电池耐高温安全测试
在25℃下,将锂离子二次电池以0.5C恒流充电至电压为4.45V,之后以4.45V恒压充电至电流为0.05C;
将电池置于烘箱中,在室温下,以2℃/min升温,直至电池燃烧失效,监控炉温和电池表面温度,记录电池失效温度。
每个实施例测试5颗电池,测试结果取平均值
(3)锂离子电池的能量密度
电池尺寸测试:取实施例1和实施例22各三颗电池,在25℃下,以0.5C恒电流充电至3.9V,然后恒电压下,充电至0.05C截止;使用千分尺测试电池厚度、宽度、长度;
在25℃下,以0.5C恒电流充电至4.45V,然后恒电压下,充电至0.025C截止;搁置5分钟;以0.1C恒电流放电至3.0V;记录锂离子电池的放电能量;
能量密度(Wh/L)=放电能量(Wh)/(电池厚度mm×电池宽度mm×电池长度mm×10
-6)
A.按照上述方法制备实施例1至29和对比例1至4的电解液以及锂离子电池。测试锂离子电池45℃间歇循环容量保持率及热失效温度,测试结果请见表2。
表2锂离子电池性能测试结果
根据实施例1与对比例1和2的比较、及实施例25与对比例3和4的结果比较可以看出,电解液中同时添加式I化合物(例如化合物1)及式III化合物(例如化合物7)可显著改善锂离子电池间歇循环性能和耐高温安全性能。
据实施例1至4和对比例1的测试结果可知,在电解液中添加适量式III化合物(例如化合物7)的同时添加范围在约0.1%至约5%的式I化合物(如化合物1)对锂离子电池的高温下的容量保持率和耐高温安全性能都有明显的提升;添加的式I化合物占电解液的质量分数为约0.2%至约1%时效果尤为理想。
根据实施例1与实施例5至6的测试结果可知,式I化合物的各实例(例如化合物1、2、和3)与式III化合物(例如化合物7)的组合添加到电解液,均能获得相似的技术效果。
据实施例1及实施例7至11和对比例2的测试结果可知,在电解液中添加适量式I化合物(例如化合物1)的同时添加范围在约0.1%至约10%的式III化合物(例如化合物7),使得锂离子电池的高温下的容量保持率和耐高温安全性能明显提升;添加的式III化合物占电解液的质量分数为0.5%至6%时效果尤为理想。
根据实施例1与实施例12至15的测试结果可知,式III化合物(例如化合物7)、式II化合物(例如化合物13)、式IV化合物(例如化合物18)或式V化合物(例如化合物20)或它们的组合与式I化合物(例如化合物1)一起添加到电解液能获得相似的技术效果。
根据实施例1及实施例16至19的测试结果可知,添加式I化合物(例如化合物1)及式III(例如化合物7)的电解液进一步加入适量的盐类添加剂(例如LiDFOB、LiPO
2F
2 或NaPF
6中的至少一者),使得锂离子电池的高温下的容量保持率和耐高温安全性能进一步改善。
根据实施例1及实施例20至22的测试结果可知,添加式I化合物(例如化合物1)及式III(例如化合物7)的电解液进一步加入适量的添加剂A(例如FEC或PS中的至少一者),使得锂离子电池的高温下的容量保持率和耐高温安全性能进一步改善。
根据实施例16与实施例23的测试结果可知,添加式I化合物(例如化合物1)、式III(例如化合物7)及盐类添加剂(例如LiDFOB)的电解液中进一步加入适量的添加剂A(例如FEC或PS中的至少一者),使得锂离子电池的高温下的容量保持率和耐高温安全性能得到进一步改善。
B.按照上述方法制备实施例1和25的电解液以及锂离子电池。测试锂离子电池能量密度,45℃间歇循环容量保持率及热失效温度,测试结果请见表3至4。
表3不同负极的电池的能量密度
表4不同负极锂离子电池的间歇循环性能及热失效温度
实施例25使用含石墨和硅氧材料的负极、实施例1使用石墨负极,两者的正极材料相同。石墨负极的克容量远低于硅氧材料。因此,实施例25(石墨和硅氧材料负极)的负载量较实施例1(石墨负极)低。实施例25得到的电池体积更小一些,其能量密度高于实施例1。
基于实施例1和实施例25的实验结果可知,无论是包含石墨负极的锂电池还是包含硅氧材料负极的锂离子电池,采用本发明的电解液都能得到明显改进的高温下的容量保持率和耐高温安全性能,对于包含石墨负极的锂电池改进效果尤为显著。
实施例26至实施例29的实验结果可知,采用特定的隔离膜能够保持较好的容量保持率的同时改善电池的热失效。
综上,本发明提供的电解液能够在正负极材料表面形成稳定的保护层,保证锂离子电池在在≥4.45V的高电压下稳定充放电工作。本发明提供的锂离子二次电池可以在高能量密度、充电截止电压≥4.45V下良好地运行,具有优越的高温间歇循环容量保持率及循环后耐高温安全性能。
以上所述,仅是本发明的几个实施例,并非对本发明做任何形式的限制,虽然本发明以较佳实施例揭示如上,然而并非用以限制本发明,任何熟悉本专业的技术人员,在不脱离本发明技术方案的范围内,利用上述揭示的技术内容做出些许的变动或修饰均等同于等效实施案例,均属于技术方案范围内。
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)
- 根据权利要求1所述的电解液,其中所述式I化合物的量占所述电解液的质量分数为0.01%至5%;所述式II化合物、式III化合物、式IV化合物或式V化合物的量占所述电解液的质量分数为0.01%至10%。
- 根据权利要求1所述的电解液,其进一步包含盐类添加剂,所述盐类添加剂包含二氟草酸硼酸锂、双草酸硼酸锂、四氟硼酸锂、二氟磷酸锂、四氟磷酸锂、四氟草酸磷酸锂、二氟双草酸磷酸锂、双氟磺酰亚胺钠、双三氟甲烷磺酰亚胺钠、六氟磷酸钠、双氟 磺酰亚胺钾、双三氟甲烷磺酰亚胺钾或六氟磷酸钾中的至少一种;所述盐类添加剂的量占所述电解液的质量分数为0.001%至2%。
- 根据权利要求1-4中任一权利要求所述的电解液,其中所述电解液进一步包含添加剂A,所述添加剂A包含氟代碳酸乙烯酯、碳酸亚乙酯、或1,3-丙烷磺内酯中的至少一种,所述添加剂A的量占所述电解液质量分数的2%至9%。
- 一种电化学装置,其包括正极、负极、隔离膜以及根据权利要求1-5中任一权利要求所述的电解液。
- 根据权利要求6所述的电化学装置,其中所述隔离膜包含聚烯烃层,所述聚烯烃层上设置有保护层;所述保护层含有勃姆石、Al 2O 3、ZnO、SiO 2、TiO 2或ZrO 2中的至少一种;所述保护层的厚度为0.1微米至3微米。
- 根据权利要求7所述电化学装置,其中所述保护层上还包含有聚合物,所述聚合物包括四氟乙烯、偏氟乙烯、六氟丙烯、全氟烷基乙烯基醚、乙烯、三氟氯乙烯、丙烯、丙烯酸、甲基丙烯酸、衣康酸、丙烯酸乙酯、丙烯酸丁酯、丙烯腈、甲基丙烯腈的均聚物及其共聚物中的至少一种,所述聚烯烃层的厚度与所述保护层的厚度至比为1∶1至20∶1。
- 根据权利要求6所述电化学装置,其中所述负极包含负极活性材料,所述负极活性材料包含含硅材料和石墨,所述含硅材料与所述石墨的重量比为5∶95至50∶50。
- 一种电子装置,其包括根据权利要求6-9中任一权利要求所述的电化学装置。
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN202080003861.9A CN112400249A (zh) | 2020-03-24 | 2020-03-24 | 一种电解液及电化学装置 |
US17/281,547 US20220115695A1 (en) | 2020-03-24 | 2020-03-24 | Electrolyte and electrochemical device comprising the same |
PCT/CN2020/080914 WO2021189255A1 (zh) | 2020-03-24 | 2020-03-24 | 一种电解液及电化学装置 |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/CN2020/080914 WO2021189255A1 (zh) | 2020-03-24 | 2020-03-24 | 一种电解液及电化学装置 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2021189255A1 true WO2021189255A1 (zh) | 2021-09-30 |
Family
ID=74624923
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/CN2020/080914 WO2021189255A1 (zh) | 2020-03-24 | 2020-03-24 | 一种电解液及电化学装置 |
Country Status (3)
Country | Link |
---|---|
US (1) | US20220115695A1 (zh) |
CN (1) | CN112400249A (zh) |
WO (1) | WO2021189255A1 (zh) |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN113078303B (zh) * | 2021-03-17 | 2022-08-26 | 宁德新能源科技有限公司 | 正极材料及包含该正极材料的电化学装置 |
WO2022217414A1 (zh) * | 2021-04-12 | 2022-10-20 | 宁德新能源科技有限公司 | 一种电化学装置及含该电化学装置的电子装置 |
EP4187669A4 (en) * | 2021-09-27 | 2023-09-20 | Contemporary Amperex Technology Co., Limited | SECONDARY BATTERY, BATTERY MODULE, BATTERY PACK AND POWER CONSUMING APPLIANCE |
CN115528309A (zh) * | 2022-11-04 | 2022-12-27 | 九江天赐高新材料有限公司 | 有机电解液和含有该有机电解液的锂离子二次电池 |
CN117219871A (zh) * | 2023-11-09 | 2023-12-12 | 宁德时代新能源科技股份有限公司 | 电解液、钠二次电池和用电装置 |
CN117219870B (zh) * | 2023-11-09 | 2024-04-16 | 宁德时代新能源科技股份有限公司 | 电解液、钠二次电池和用电装置 |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2010037322A (ja) * | 2008-07-11 | 2010-02-18 | Wako Pure Chem Ind Ltd | 環状亜硫酸エステルの製造方法 |
TW201526343A (zh) * | 2013-12-18 | 2015-07-01 | Univ Nat Taiwan Science Tech | 鋰電池以及鋰電池用的電解液添加劑 |
CN105074993A (zh) * | 2013-12-09 | 2015-11-18 | Sk新技术株式会社 | 用于锂二次电池的电解液及包含其的锂二次电池 |
CN105591158A (zh) * | 2016-03-21 | 2016-05-18 | 东莞市杉杉电池材料有限公司 | 一种三元正极材料锂离子电池及其电解液 |
CN106905291A (zh) * | 2015-12-22 | 2017-06-30 | 天津鑫源广泰新材料科技有限公司 | 一种3,3—联二硫酸乙烯酯的生产方法 |
CN110386916A (zh) * | 2019-07-23 | 2019-10-29 | 常熟市常吉化工有限公司 | 一种环状硫酸酯的合成方法 |
Family Cites Families (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2011138623A (ja) * | 2009-12-25 | 2011-07-14 | Sanyo Electric Co Ltd | 非水系二次電池 |
US9666906B2 (en) * | 2014-05-15 | 2017-05-30 | Nano And Advanced Materials Institute Limited | High voltage electrolyte and lithium ion battery |
KR20160128135A (ko) * | 2015-04-28 | 2016-11-07 | 삼성에스디아이 주식회사 | 리튬 이차 전지용 세퍼레이터 및 이를 포함하는 리튬 이차 전지 |
CN106941191B (zh) * | 2016-01-04 | 2020-03-24 | 宁德新能源科技有限公司 | 锂离子电池及其非水电解液 |
CN107017432B (zh) * | 2016-01-28 | 2019-02-22 | 宁德新能源科技有限公司 | 非水电解液及锂离子电池 |
CN105826608A (zh) * | 2016-05-25 | 2016-08-03 | 宁德新能源科技有限公司 | 一种电解液以及包括该电解液的锂离子电池 |
CN105977525A (zh) * | 2016-07-08 | 2016-09-28 | 深圳新宙邦科技股份有限公司 | 一种使用非水电解液的锂离子电池 |
KR102492766B1 (ko) * | 2017-06-15 | 2023-01-26 | 선천 캡쳄 테크놀로지 컴퍼니 리미티드 | 이차전지용 전해액 및 이를 포함하는 이차전지 |
WO2020026914A1 (ja) * | 2018-07-30 | 2020-02-06 | 株式会社村田製作所 | リチウムイオン二次電池 |
KR102633167B1 (ko) * | 2018-08-02 | 2024-02-05 | 에스케이온 주식회사 | 리튬 이차전지 |
CN111106383B (zh) * | 2018-10-26 | 2021-05-18 | 宁德新能源科技有限公司 | 电解液及锂离子电池 |
CN112234209B (zh) * | 2019-06-03 | 2021-11-23 | 宁德新能源科技有限公司 | 电化学装置 |
CN110767939B (zh) * | 2019-10-18 | 2021-06-11 | 宁德时代新能源科技股份有限公司 | 用于锂离子电池的电解液、锂离子电池、电池模块、电池包及装置 |
-
2020
- 2020-03-24 CN CN202080003861.9A patent/CN112400249A/zh active Pending
- 2020-03-24 US US17/281,547 patent/US20220115695A1/en active Pending
- 2020-03-24 WO PCT/CN2020/080914 patent/WO2021189255A1/zh active Application Filing
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2010037322A (ja) * | 2008-07-11 | 2010-02-18 | Wako Pure Chem Ind Ltd | 環状亜硫酸エステルの製造方法 |
CN105074993A (zh) * | 2013-12-09 | 2015-11-18 | Sk新技术株式会社 | 用于锂二次电池的电解液及包含其的锂二次电池 |
TW201526343A (zh) * | 2013-12-18 | 2015-07-01 | Univ Nat Taiwan Science Tech | 鋰電池以及鋰電池用的電解液添加劑 |
CN106905291A (zh) * | 2015-12-22 | 2017-06-30 | 天津鑫源广泰新材料科技有限公司 | 一种3,3—联二硫酸乙烯酯的生产方法 |
CN105591158A (zh) * | 2016-03-21 | 2016-05-18 | 东莞市杉杉电池材料有限公司 | 一种三元正极材料锂离子电池及其电解液 |
CN110386916A (zh) * | 2019-07-23 | 2019-10-29 | 常熟市常吉化工有限公司 | 一种环状硫酸酯的合成方法 |
Also Published As
Publication number | Publication date |
---|---|
US20220115695A1 (en) | 2022-04-14 |
CN112400249A (zh) | 2021-02-23 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US11646447B2 (en) | Electrolyte and electrochemical device | |
WO2021189255A1 (zh) | 一种电解液及电化学装置 | |
JP7311497B2 (ja) | リチウムイオン電池および電子デバイス | |
CN112335090B (zh) | 电解液和使用其的电化学装置 | |
WO2021218267A1 (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 | |
WO2021223181A1 (zh) | 一种电解液及电化学装置 | |
WO2022052019A1 (zh) | 电化学装置和电子装置 | |
JP7311593B2 (ja) | 電解液及び電気化学装置 | |
WO2023070989A1 (zh) | 电化学装置和包含其的电子装置 | |
CN111697267A (zh) | 电解液和包含电解液的电化学装置及电子装置 | |
US11830981B2 (en) | Electrolyte and electrochemical device | |
US20220223915A1 (en) | Electrolyte, electrochemical device including same, and electronic device | |
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 | |
CN111600065B (zh) | 电解液和使用其的电化学装置 | |
WO2021196019A1 (zh) | 一种电解液及电化学装置 | |
CN116759648B (zh) | 一种电化学装置及包括其的电子装置 | |
JP7515960B2 (ja) | 非水電解液およびそれを含むリチウム二次電池 | |
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 | |
WO2021174417A1 (zh) | 一种电解液及电化学装置 | |
WO2023123427A1 (zh) | 电化学装置和包含其的电子装置 | |
CN116454400A (zh) | 电化学装置和包括其的电子装置 |
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: 20927089 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: 20927089 Country of ref document: EP Kind code of ref document: A1 |