WO2023236510A1 - Electrolyte solution and preparation method therefor, and lithium-ion battery - Google Patents

Electrolyte solution and preparation method therefor, and lithium-ion battery Download PDF

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Publication number
WO2023236510A1
WO2023236510A1 PCT/CN2022/141937 CN2022141937W WO2023236510A1 WO 2023236510 A1 WO2023236510 A1 WO 2023236510A1 CN 2022141937 W CN2022141937 W CN 2022141937W WO 2023236510 A1 WO2023236510 A1 WO 2023236510A1
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Prior art keywords
electrolyte
solvent
lithium
carbonate
electrolyte solution
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PCT/CN2022/141937
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French (fr)
Chinese (zh)
Inventor
刘世琦
刘建文
何思聪
王石泉
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湖北万润新能源科技股份有限公司
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Publication of WO2023236510A1 publication Critical patent/WO2023236510A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0569—Liquid materials characterised by the solvents
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—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
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present invention relates to the technical field of lithium-ion battery electrolyte solutions, and specifically to an electrolyte solution and a preparation method thereof, and a lithium-ion battery.
  • Lithium-ion batteries are widely used in the automotive field due to their advantages such as high energy density, low self-discharge, long life, high discharge power, and environmental protection.
  • battery-powered vehicles have become increasingly popular.
  • the battery's application performance, especially high and low temperature performance has received more and more attention.
  • the method of modifying the positive and negative electrode materials is often used in the prior art. Although this method can improve the high and low temperature performance of the battery to a certain extent, its preparation process is complex and there are many types of positive and negative electrode materials, making it difficult to implement.
  • the first object of the present invention is to provide an electrolyte that can improve the performance of lithium-ion batteries in a wide temperature range including high temperatures (55 °C) and low temperature (-30 °C) conditions.
  • the second object of the present invention is to provide a method for preparing the electrolyte, which has the advantages of simple and convenient operation, mild conditions, short process flow, short time and easy mass production.
  • the third object of the present invention is to provide a lithium-ion battery that uses a specific electrolyte to reduce the viscosity of the system, effectively reduce the internal resistance of the battery under high and low temperatures, and improve the battery's electrical performance under high and low temperatures. chemical properties.
  • the invention also provides an electrolyte solution, which includes an electrolyte lithium salt and a solvent;
  • the solvent includes carbonate solvent and/or carboxylate solvent
  • the molar concentration of the electrolyte lithium salt in the electrolyte is 0.5 ⁇ 2mol/L, including but not limited to 0.6mol/L, 0.7mol/L, 0.8mol/L, 0.9mol/L, 1mol/L, 1.1mol/L
  • the molar concentration of the electrolyte lithium salt in the electrolyte solution refers to the total molar concentration of all electrolyte lithium salts.
  • the present invention can use a specific type of solvent, that is, use any one of a carbonate solvent and a carboxylate solvent or a mixture of the two, and keep the molar concentration of the electrolyte lithium salt in the electrolyte within a specific range. Preparing an electrolyte suitable for a wide temperature range environment can effectively improve the electrochemical properties of lithium-ion batteries, especially the electrochemical cycle and rate performance of lithium-ion batteries.
  • the solvent includes a mixture of the carbonate solvent and the carboxylate solvent, and the volume ratio of the carbonate solvent to the carboxylate solvent is 55 to 85 (including but not limited to 52 , 54, 55, 56, 58, 60, 62, 64, 65, 67, 69, 70, 72, 74, 75, 78, 80, 82, 83, 84 or any two of them Range value between): 15 ⁇ 45 (including but not limited to 16, 17, 18, 19, 20, 22, 24, 25, 27, 29, 30, 32, 34, 35, 37, 39, 40, 41 , 42, 43, 44 any one of the point value or any range value between the two).
  • the melting point of the electrolyte can be effectively reduced.
  • the introduction of a specific amount of carboxylate solvent can reduce the viscosity of the electrolyte, thereby effectively improving the electrochemical performance of lithium-ion batteries at high and low temperatures.
  • the volume ratio of the carbonate solvent and the carboxylate solvent is 60-80:20-40, such as 60:40, or 80:20, or 70:30.
  • the carbonate solvent includes ethylene carbonate (EC), propylene carbonate (PC), vinylene carbonate (VC), dimethyl carbonate (DMC), diethyl carbonate (DEC) and methyl ethyl carbonate.
  • EC ethylene carbonate
  • PC propylene carbonate
  • VC vinylene carbonate
  • DMC dimethyl carbonate
  • DEC diethyl carbonate
  • EMC esters
  • the carbonate solvent includes at least two of ethylene carbonate, propylene carbonate, vinylene carbonate, dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate.
  • Using at least two different types of carbonate solvents is beneficial to further improving the cycle stability performance of the battery.
  • the carboxylic acid ester solvent includes methyl acetate (MA), ethyl acetate (EA), methyl butyrate (MB), methyl propionate (MP), methyl formate (MF), ethyl propionate At least one of ester (EP), ethyl butyrate (EB) and n-butyl acetate (BA).
  • the molar concentration of the electrolyte lithium salt in the electrolyte is 0.9 to 1.6 mol/L, including but not limited to 1 mol/L, 1.1 mol/L, 1.2 mol/L, 1.3 mol/L, and 1.4 mol/L. , 1.5 mol/L or any range value between the two.
  • the molar concentration of the electrolyte lithium salt in the electrolyte is 1 to 1.2 mol/L, including but not limited to any of 1.05 mol/L, 1.1 mol/L, 1.15 mol/L, and 1.2 mol/L.
  • the electrolyte lithium salt includes lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium difluoroborate (LiDFOB), lithium dioxaloborate (LiBOB), lithium bisfluorosulfonyl imide (LiFSI ) and lithium bistrifluoromethylsulfonimide (LiTFSI), more preferably at least two.
  • LiPF 6 lithium hexafluorophosphate
  • LiBF 4 lithium tetrafluoroborate
  • LiDFOB lithium difluoroborate
  • LiBOB lithium dioxaloborate
  • LiFSI lithium bisfluorosulfonyl imide
  • LiTFSI lithium bistrifluoromethylsulfonimide
  • the electrolyte lithium salt includes lithium hexafluorophosphate, lithium tetrafluoroborate, lithium difluoroxaloborate, lithium dioxaloborate, lithium bisfluorosulfonimide and bistrifluoromethylsulfonimide.
  • Two types of lithium amide For example, the electrolyte lithium salt is selected from the group consisting of lithium hexafluorophosphate and lithium tetrafluoroborate; or, the electrolyte lithium salt is selected from the group consisting of lithium hexafluorophosphate and lithium difluoroborate.
  • Two different types of electrolyte lithium salts are respectively a first electrolyte lithium salt and a second electrolyte lithium salt.
  • the first electrolyte lithium salt in the electrolyte solution and the second electrolyte lithium salt in the electrolyte solution The molar concentration ratio of salt is 0.2 ⁇ 0.8:0.2 ⁇ 0.8, and you can also choose 0.8:0.2, 0.6:0.4, 0.5:0.5, 0.4:0.6 or 0.2:0.8.
  • the ratio of the molar concentration of the first electrolyte lithium salt in the electrolyte solution to the molar concentration of the second electrolyte lithium salt in the electrolyte solution is 0.8:0.2, or 0.2:0.8, or 0.6 :0.4, or 0.4:0.6, or 0.5:0.5.
  • the electrolyte lithium salt includes lithium hexafluorophosphate, lithium tetrafluoroborate, lithium difluoroxaloborate, lithium dioxaloborate, lithium bisfluorosulfonimide and bistrifluoromethylsulfonimide. At least three of the lithium amines.
  • the electrolyte further includes additives.
  • the additive includes at least one of fluoroethylene carbonate, vinylene carbonate, vinyl sulfate, dimethyl sulfate and butylene sulfite.
  • the present invention can form a passivation film that stably exists in an organic solvent on the electrode surface, that is, an SEI film.
  • This passivation film can effectively prevent excessive side reactions between solvent molecules and electrode materials and inhibit the volume expansion of the electrode.
  • the mass of the additive accounts for 0.1% to 5.5% of the total mass of the electrolyte.
  • the cycle retention rate of the lithium-ion battery made from the electrolyte at -30°C (minus 30°C) is greater than 40% (including but not limited to 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 55%, 58%, 60%, 61%, 62%, 63%, 64% , 65%, 66%, 67%, 68%, 69%, 70%, 73%, 75%, 78%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87 %, 88%, 89%, 90% or any one of the range values between the two), preferably greater than 60%, more preferably greater than 70%, even more preferably greater than 80%, Even more preferably, it is greater than 86%.
  • the cycle retention rate of the lithium-ion battery made from the electrolyte at 55°C is greater than 50% (including but not limited to 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72% ,73%,75%,78%,80%,81%,82%,83%,84%,85%,86%,87%,88%,89%,90%,91%,92%,93 %, 94%, 95% or the range value between any two), preferably greater than 60%, more preferably greater than 70%, further preferably greater than 80%, and still further Preferably it is greater than 88%.
  • the present invention also provides a method for preparing the electrolyte as described above, which includes the following steps:
  • the preparation method has the advantages of simple and convenient operation, mild conditions, short process flow, short time and easy mass production.
  • the step of adding additives thereto and mixing them uniformly again is also included.
  • the present invention also provides a lithium ion battery, including the electrolyte solution as described above, or the electrolyte solution prepared by the electrolyte solution preparation method as described above.
  • the lithium-ion battery reduces the viscosity of the system, effectively reduces the internal resistance of the battery at high and low temperatures, and improves the electrochemical performance of the battery at high and low temperatures.
  • the lithium ion battery includes a lithium nickel cobalt manganate lithium ion battery.
  • the lithium nickel cobalt manganate lithium ion battery includes a positive electrode sheet, a separator and a negative electrode sheet.
  • the positive electrode sheet includes a positive electrode current collector and a positive electrode material coated on the positive electrode current collector.
  • the diameter of the coated surface of the cathode material on the cathode current collector is 10 to 15 mm (you can also choose 11 mm, 12 mm, 13 mm, 14 mm or 14.5 mm), more preferably 12 mm.
  • the cathode material includes the following components in terms of parts by mass: 75 to 85 parts of lithium nickel cobalt manganate (76 parts, 77 parts, 78 parts, 79 parts, 80 parts, 81 parts, 81.5 parts can also be selected) parts, 82 parts, 82.3 parts, 83 parts or 84 parts), 5 to 15 parts of conductive agent (you can also choose 6 parts, 7 parts, 7.8 parts, 8 parts, 8.9 parts, 9 parts, 10 parts, 11 parts, 11.5 parts parts, 12 parts, 13 parts or 14 parts) and 5 to 15 parts of adhesive (you can also choose 6 parts, 7 parts, 7.5 parts, 8 parts, 8.2 parts, 9 parts, 10 parts, 10.6 parts, 11 parts, 11.5 servings, 12 servings, 13 servings or 14 servings).
  • 75 to 85 parts of lithium nickel cobalt manganate 76 parts, 77 parts, 78 parts, 79 parts, 80 parts, 81 parts, 81.5 parts can also be selected
  • parts 82 parts, 82.3 parts, 83 parts or 84 parts
  • the positive electrode material includes the following components in parts by mass: 78 to 82.5 parts of lithium nickel cobalt manganate, 7.4 to 12.1 parts of conductive agent, and 7.4 to 12.1 parts of binder.
  • the electrolyte provided by the present invention can improve the performance of lithium-ion batteries in a wide temperature range, including high temperatures (55°C), by using a specific type of solvent and keeping the molar concentration of the electrolyte lithium salt in the electrolyte within a specific range. and electrochemical performance under low temperature (-30°C) conditions, effectively improving the electrochemical cycle stability performance of lithium-ion batteries.
  • the electrolyte provided by the present invention can form an excellent SEI film by using a carbonate solvent and a carboxylate solvent with a volume ratio within a specific range and a specific amount of additives, thereby improving the conductivity. Moreover, the introduction of a specific amount of carboxylate solvent can reduce the viscosity of the electrolyte, thereby further improving the electrochemical performance of lithium-ion batteries at high and low temperatures.
  • the lithium-ion battery provided by the present invention reduces the viscosity of the system by using a specific electrolyte, effectively reduces the internal resistance of the battery at high and low temperatures, and improves the electrochemical performance of the battery at high and low temperatures.
  • the electrolyte solution provided in this embodiment consists of an electrolyte lithium salt and a solvent.
  • the electrolyte lithium salt is lithium hexafluorophosphate (LiPF 6 ).
  • the solvent is ethylene carbonate (EC) and diethyl carbonate (DEC) with a volume ratio of 1:1.
  • the molar concentration of lithium hexafluorophosphate (LiPF 6 ) in the electrolyte is 1 mol/L. That is, the total molar concentration of the electrolyte lithium salt in the electrolyte solution is 1 mol/L.
  • the preparation method of the electrolyte provided in this embodiment includes the following steps: uniformly mixing the electrolyte lithium salt and the solvent to obtain an electrolyte.
  • the electrolyte solution provided in this embodiment consists of an electrolyte lithium salt and a solvent.
  • the electrolyte lithium salt is a mixture of lithium hexafluorophosphate (LiPF 6 ) and lithium tetrafluoroborate (LiBF 4 ).
  • the solvent is ethylene carbonate (EC) and diethyl carbonate (DEC) with a volume ratio of 1:1.
  • the molar concentration of lithium hexafluorophosphate (LiPF 6 ) in the electrolyte solution is 0.8 mol/L
  • the molar concentration of lithium tetrafluoroborate (LiBF 4 ) in the electrolyte solution is 0.2 mol/L. That is, the total molar concentration of the electrolyte lithium salt in the electrolyte solution is 1 mol/L.
  • the preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 1.
  • the electrolyte solution provided in this embodiment consists of an electrolyte lithium salt and a solvent.
  • the electrolyte lithium salt is a mixture of lithium hexafluorophosphate (LiPF 6 ) and lithium tetrafluoroborate (LiBF 4 ).
  • the solvent is ethylene carbonate (EC) and diethyl carbonate (DEC) with a volume ratio of 1:1.
  • the molar concentration of lithium hexafluorophosphate (LiPF 6 ) in the electrolyte solution is 0.6 mol/L, and the molar concentration of lithium tetrafluoroborate (LiBF 4 ) in the electrolyte solution is 0.4 mol/L. That is, the total molar concentration of the electrolyte lithium salt in the electrolyte solution is 1 mol/L.
  • the preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 1.
  • the electrolyte solution provided in this embodiment consists of an electrolyte lithium salt and a solvent.
  • the electrolyte lithium salt is a mixture of lithium hexafluorophosphate (LiPF 6 ) and lithium difluorooxalate borate (LiDFOB).
  • the solvent is ethylene carbonate (EC) and diethyl carbonate (DEC) with a volume ratio of 1:1.
  • the molar concentration of lithium hexafluorophosphate (LiPF 6 ) in the electrolyte is 0.8 mol/L
  • the molar concentration of lithium difluorooxalate borate (LiDFOB) in the electrolyte is 0.2 mol/L. That is, the total molar concentration of the electrolyte lithium salt in the electrolyte solution is 1 mol/L.
  • the preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 1.
  • the electrolyte solution provided in this embodiment consists of an electrolyte lithium salt and a solvent.
  • the electrolyte lithium salt is a mixture of lithium hexafluorophosphate (LiPF 6 ) and lithium difluorooxalate borate (LiDFOB).
  • the solvent is ethylene carbonate (EC) and diethyl carbonate (DEC) with a volume ratio of 1:1.
  • the molar concentration of lithium hexafluorophosphate (LiPF 6 ) in the electrolyte is 0.6 mol/L
  • the molar concentration of lithium difluorooxalate borate (LiDFOB) in the electrolyte is 0.4 mol/L. That is, the total molar concentration of the electrolyte lithium salt in the electrolyte solution is 1 mol/L.
  • the preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 1.
  • the electrolyte solution provided in this embodiment consists of an electrolyte lithium salt and a solvent.
  • the electrolyte lithium salt is lithium hexafluorophosphate (LiPF 6 ).
  • the solvent is a carbonate solvent and a carboxylic acid ester solvent with a volume ratio of 3:2 (60:40), wherein the carbonate solvent is ethylene carbonate (EC) and diethyl carbonate (DEC) with a volume ratio of 1:1 , the carboxylate solvent is n-butyl acetate (BA).
  • EC ethylene carbonate
  • DEC diethyl carbonate
  • BA n-butyl acetate
  • the molar concentration of lithium hexafluorophosphate (LiPF 6 ) in the electrolyte is 1 mol/L. That is, the total molar concentration of the electrolyte lithium salt in the electrolyte solution is 1 mol/L.
  • the preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 1.
  • the electrolyte solution provided in this embodiment consists of an electrolyte lithium salt and a solvent.
  • the electrolyte lithium salt is a mixture of lithium hexafluorophosphate (LiPF 6 ) and lithium tetrafluoroborate (LiBF 4 ).
  • the solvent is a carbonate solvent and a carboxylic acid ester solvent with a volume ratio of 3:2 (60:40), wherein the carbonate solvent is ethylene carbonate (EC) and diethyl carbonate (DEC) with a volume ratio of 1:1 , the carboxylate solvent is n-butyl acetate (BA).
  • EC ethylene carbonate
  • DEC diethyl carbonate
  • BA n-butyl acetate
  • the molar concentration of lithium hexafluorophosphate (LiPF 6 ) in the electrolyte solution is 0.8 mol/L
  • the molar concentration of lithium tetrafluoroborate (LiBF 4 ) in the electrolyte solution is 0.2 mol/L. That is, the total molar concentration of the electrolyte lithium salt in the electrolyte solution is 1 mol/L.
  • the preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 1.
  • the electrolyte solution provided in this embodiment consists of an electrolyte lithium salt and a solvent.
  • the electrolyte lithium salt is a mixture of lithium hexafluorophosphate (LiPF 6 ) and lithium difluorooxalate borate (LiDFOB).
  • the solvent is a carbonate solvent and a carboxylic acid ester solvent with a volume ratio of 3:2 (60:40), wherein the carbonate solvent is ethylene carbonate (EC) and diethyl carbonate (DEC) with a volume ratio of 1:1 , the carboxylate solvent is n-butyl acetate (BA).
  • EC ethylene carbonate
  • DEC diethyl carbonate
  • BA n-butyl acetate
  • the molar concentration of lithium hexafluorophosphate (LiPF 6 ) in the electrolyte is 0.8 mol/L
  • the molar concentration of lithium difluorooxalate borate (LiDFOB) in the electrolyte is 0.2 mol/L. That is, the total molar concentration of the electrolyte lithium salt in the electrolyte solution is 1 mol/L.
  • the preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 1.
  • the electrolyte solution provided in this embodiment consists of an electrolyte lithium salt and a solvent.
  • the electrolyte lithium salt is a mixture of lithium hexafluorophosphate (LiPF 6 ) and lithium tetrafluoroborate (LiBF 4 ).
  • the solvent is a carbonate solvent and a carboxylic acid ester solvent with a volume ratio of 4:1 (80:20), wherein the carbonate solvent is ethylene carbonate (EC) and diethyl carbonate (DEC) with a volume ratio of 1:1 , the carboxylate solvent is n-butyl acetate (BA).
  • EC ethylene carbonate
  • DEC diethyl carbonate
  • BA n-butyl acetate
  • the molar concentration of lithium hexafluorophosphate (LiPF 6 ) in the electrolyte solution is 0.8 mol/L
  • the molar concentration of lithium tetrafluoroborate (LiBF 4 ) in the electrolyte solution is 0.2 mol/L. That is, the total molar concentration of the electrolyte lithium salt in the electrolyte solution is 1 mol/L.
  • the preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 1.
  • the electrolyte solution provided in this embodiment consists of an electrolyte lithium salt and a solvent.
  • the electrolyte lithium salt is a mixture of lithium hexafluorophosphate (LiPF 6 ) and lithium difluorooxalate borate (LiDFOB).
  • the solvent is a carbonate solvent and a carboxylic acid ester solvent with a volume ratio of 4:1 (80:20), wherein the carbonate solvent is ethylene carbonate (EC) and diethyl carbonate (DEC) with a volume ratio of 1:1 , the carboxylate solvent is n-butyl acetate (BA).
  • EC ethylene carbonate
  • DEC diethyl carbonate
  • BA n-butyl acetate
  • the molar concentration of lithium hexafluorophosphate (LiPF 6 ) in the electrolyte is 0.8 mol/L
  • the molar concentration of lithium difluorooxalate borate (LiDFOB) in the electrolyte is 0.2 mol/L. That is, the total molar concentration of the electrolyte lithium salt in the electrolyte solution is 1 mol/L.
  • the preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 1.
  • the electrolyte provided in this embodiment consists of electrolyte lithium salt, solvent and additives.
  • the electrolyte lithium salt is lithium hexafluorophosphate (LiPF 6 ).
  • the solvent is a carbonate solvent and a carboxylic acid ester solvent with a volume ratio of 4:1 (80:20), wherein the carbonate solvent is ethylene carbonate (EC) and diethyl carbonate (DEC) with a volume ratio of 1:1 , the carboxylate solvent is n-butyl acetate (BA).
  • EC ethylene carbonate
  • DEC diethyl carbonate
  • BA n-butyl acetate
  • the molar concentration of lithium hexafluorophosphate (LiPF 6 ) in the electrolyte is 1 mol/L. That is, the total molar concentration of the electrolyte lithium salt in the electrolyte solution is 1 mol/L.
  • the additive is vinyl sulfate (DTD).
  • DTD vinyl sulfate
  • the preparation method of the electrolyte provided in this embodiment includes the following steps: after mixing the electrolyte lithium salt and the solvent uniformly, adding additives thereto, and mixing uniformly again to obtain the electrolyte solution.
  • the electrolyte provided in this embodiment consists of electrolyte lithium salt, solvent and additives.
  • the electrolyte lithium salt is a mixture of lithium hexafluorophosphate (LiPF 6 ) and lithium tetrafluoroborate (LiBF 4 ).
  • the solvent is a carbonate solvent and a carboxylic acid ester solvent with a volume ratio of 4:1 (80:20), wherein the carbonate solvent is ethylene carbonate (EC) and diethyl carbonate (DEC) with a volume ratio of 1:1 , the carboxylate solvent is n-butyl acetate (BA).
  • EC ethylene carbonate
  • DEC diethyl carbonate
  • BA n-butyl acetate
  • the molar concentration of lithium hexafluorophosphate (LiPF 6 ) in the electrolyte solution is 0.8 mol/L
  • the molar concentration of lithium tetrafluoroborate (LiBF 4 ) in the electrolyte solution is 0.2 mol/L. That is, the total molar concentration of the electrolyte lithium salt in the electrolyte solution is 1 mol/L.
  • the additive is vinyl sulfate (DTD).
  • DTD vinyl sulfate
  • the preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 11.
  • the electrolyte provided in this embodiment consists of electrolyte lithium salt, solvent and additives.
  • the electrolyte lithium salt is a mixture of lithium hexafluorophosphate (LiPF 6 ) and lithium difluorooxalate borate (LiDFOB).
  • the solvent is a carbonate solvent and a carboxylic acid ester solvent with a volume ratio of 4:1 (80:20), wherein the carbonate solvent is ethylene carbonate (EC) and diethyl carbonate (DEC) with a volume ratio of 1:1 , the carboxylate solvent is n-butyl acetate (BA).
  • EC ethylene carbonate
  • DEC diethyl carbonate
  • BA n-butyl acetate
  • the molar concentration of lithium hexafluorophosphate (LiPF 6 ) in the electrolyte is 0.8 mol/L
  • the molar concentration of lithium difluorooxalate borate (LiDFOB) in the electrolyte is 0.2 mol/L. That is, the total molar concentration of the electrolyte lithium salt in the electrolyte solution is 1 mol/L.
  • the additive is vinyl sulfate (DTD).
  • DTD vinyl sulfate
  • the preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 11.
  • composition of the electrolyte provided in this embodiment is basically the same as that in Embodiment 12, and the only difference is that the mass of DTD accounts for 3% of the total mass of the electrolyte.
  • the preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 11.
  • composition of the electrolyte provided in this embodiment is basically the same as that in Embodiment 13, and the only difference is that the mass of DTD accounts for 3% of the total mass of the electrolyte.
  • the preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 11.
  • composition of the electrolyte provided in this embodiment is basically the same as that in Embodiment 12, and the only difference is that the mass of DTD accounts for 5% of the total mass of the electrolyte.
  • the preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 11.
  • composition of the electrolyte provided in this embodiment is basically the same as that in Embodiment 13, and the only difference is that the mass of DTD accounts for 5% of the total mass of the electrolyte.
  • the preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 11.
  • the electrolyte provided in this embodiment consists of electrolyte lithium salt, solvent and additives.
  • the electrolyte lithium salt is a mixture of lithium dioxaloborate (LiBOB) and lithium bisfluorosulfonimide (LiFSI).
  • the solvent is a carbonate solvent and a carboxylic acid ester solvent with a volume ratio of 4:1 (80:20).
  • the carbonate solvent is ethyl methyl carbonate (EMC) and vinylene carbonate (VC) with a volume ratio of 1:1. ), the carboxylate solvent is methyl propionate (MP).
  • the molar concentration of lithium dioxaloborate (LiBOB) in the electrolyte is 0.6 mol/L
  • the molar concentration of lithium bisfluorosulfonimide (LiFSI) in the electrolyte is 0.6 mol/L. That is, the total molar concentration of the electrolyte lithium salt in the electrolyte solution is 1.2 mol/L.
  • the additive is vinyl sulfate (DTD).
  • DTD vinyl sulfate
  • the preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 11.
  • the electrolyte provided in this embodiment consists of electrolyte lithium salt, solvent and additives.
  • the electrolyte lithium salt is a mixture of lithium dioxaloborate (LiBOB), lithium difluorooxaloborate (LiDFOB) and lithium bistrifluoromethylsulfonyl imide (LiTFSI).
  • the solvent is a carbonate solvent and a carboxylate solvent with a volume ratio of 4:1 (80:20).
  • the carbonate solvent is dimethyl carbonate (DMC) and vinylene carbonate (VC) with a volume ratio of 1:1.
  • the carboxylate solvent is n-butyl acetate (BA).
  • the molar concentration of lithium dioxaloborate (LiBOB) in the electrolyte is 1mol/L
  • the molar concentration of lithium difluoroxaloborate (LiDFOB) in the electrolyte is 0.3mol/L
  • the molar concentration of bistrifluoromethylsulfonate in the electrolyte is
  • the molar concentration of lithium imide (LiTFSI) is 0.3mol/L. That is, the total molar concentration of the electrolyte lithium salt in the electrolyte solution is 1.6 mol/L.
  • the additive is vinylene carbonate (VC).
  • VC vinylene carbonate
  • the mass of VC accounts for 1% of the total mass of the electrolyte.
  • the preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 11.
  • composition of the electrolyte provided in this comparative example is basically the same as that in Example 16. The only difference is that the additive vinyl sulfate (DTD) is replaced by fluoroethylene carbonate (FEC), but its dosage remains unchanged (that is, the mass of FEC 5% of the total mass of the electrolyte).
  • DTD additive vinyl sulfate
  • FEC fluoroethylene carbonate
  • the preparation method of the electrolyte provided in this comparative example is the same as that in Example 16.
  • composition of the electrolyte provided in this comparative example is basically the same as that in Example 17. The only difference is that the additive vinyl sulfate (DTD) is replaced by fluoroethylene carbonate (FEC), but its dosage remains unchanged (that is, the mass of FEC 5% of the total mass of the electrolyte).
  • DTD additive vinyl sulfate
  • FEC fluoroethylene carbonate
  • the preparation method of the electrolyte provided in this comparative example is the same as that in Example 17.
  • the composition of the electrolyte provided in this comparative example is basically the same as that in Example 17. The only difference is that the molar concentration of lithium hexafluorophosphate (LiPF 6 ) in the electrolyte is replaced with 2 mol/L, and the lithium difluoroxalate borate in the electrolyte is replaced.
  • the molar concentration of (LiDFOB) was replaced with 0.5 mol/L. That is, the total molar concentration of the electrolyte lithium salt in the electrolyte solution is 2.5 mol/L.
  • the preparation method of the electrolyte provided in this comparative example is the same as that in Example 17.
  • the composition of the electrolyte provided in this comparative example is basically the same as that in Example 17. The only difference is that the volume ratio of the carbonate solvent and the carboxylate solvent is replaced by 1:4 (that is, the volume ratio of the solvent is 1:4 (20 :80) carbonate solvent and carboxylate solvent, while the carbonate solvent is still ethylene carbonate and diethyl carbonate with a volume ratio of 1:1, and the carboxylate solvent is still n-butyl acetate).
  • the preparation method of the electrolyte provided in this comparative example is the same as that in Example 17.
  • composition of the electrolyte provided in this comparative example is basically the same as that in Example 17, and the only difference is that the mass of DTD accounts for 7% of the total mass of the electrolyte.
  • the preparation method of the electrolyte provided in this comparative example is the same as that in Example 17.
  • Table 1 The composition of the electrolyte of each group and the cycle retention rate of each group of batteries
  • the present invention can form an excellent SEI film by using a carbonate solvent and a carboxylate solvent with a volume ratio within a specific range, and using a specific amount of additives, thereby improving the battery cycle retention rate and average Coulombic efficiency effectively improves the electrochemical performance of lithium-ion batteries at high and low temperatures.
  • Example 16 By comparing the experimental results of Example 16 with Comparative Example 1, Example 17 and Comparative Example 2, it can be seen that when the additive vinyl sulfate (DTD) of the electrolyte is replaced with fluoroethylene carbonate (FEC), the lithium-ion battery The high and low temperature cycle performance deteriorates. This shows that the specific types of additives provided by the present invention can significantly improve the electrochemical performance of lithium-ion batteries at high and low temperatures.
  • DTD additive vinyl sulfate
  • FEC fluoroethylene carbonate
  • Example 17 By comparing the experimental results of Example 17 and Comparative Examples 3, 4 and 5, it can be seen that the total molar concentration of the electrolyte lithium salt in the electrolyte solution, the volume ratio of the carbonate solvent and the carboxylate solvent, and the The dosage will have a great impact on the electrochemical performance of the battery under high and low temperatures. By adopting the parameter range provided by the present invention, more excellent electrochemical performance can be obtained.

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Abstract

The present invention relates to the technical field of electrolyte solutions for lithium-ion batteries, in particular to an electrolyte solution and a preparation method therefor, and a lithium-ion battery. The electrolyte solution comprises an electrolyte lithium salt and a solvent, wherein the solvent comprises a carbonate solvent and/or a carboxylate solvent; and the molar concentration of the electrolyte lithium salt in the electrolyte solution is 0.5-2 mol/L. By using a specific type of solvent and enabling the molar concentration of the electrolyte lithium salt in the electrolyte solution to be within a specific range, the electrolyte solution can improve the electrochemical performance of a lithium-ion battery under conditions of a wide temperature range including a high temperature (55°C) and a low temperature (-30°C), thereby effectively improving the electrochemical cycling and rate capabilities of the lithium-ion battery.

Description

一种电解液及其制备方法、锂离子电池Electrolyte and preparation method thereof, lithium-ion battery
本申请要求2022年6月7日提交的，申请号为202210637292.4，发明名称为“一种电解液及其制备方法、锂离子电池”的中国发明专利申请的优先权，该申请的公开内容以引用的方式并入本文。This application claims the priority of the Chinese invention patent application submitted on June 7, 2022, with the application number 202210637292.4 and the invention title "An electrolyte and its preparation method, lithium ion battery". The disclosure content of this application is cited incorporated into this article.
技术领域Technical field
本发明涉及锂离子电池电解液技术领域，具体而言，涉及一种电解液及其制备方法、锂离子电池。The present invention relates to the technical field of lithium-ion battery electrolyte solutions, and specifically to an electrolyte solution and a preparation method thereof, and a lithium-ion battery.
背景技术Background technique
锂离子电池因具有高能量密度、自放电小、寿命长、高放电功率和环保等优势，被广泛应用于汽车领域。近年来，随着环保理念的发展，采用电池的动力汽车越来越受青睐。电池作为电动汽车中的重要部件之一，其应用性能，尤其是高低温性能被愈加重视。Lithium-ion batteries are widely used in the automotive field due to their advantages such as high energy density, low self-discharge, long life, high discharge power, and environmental protection. In recent years, with the development of environmental protection concepts, battery-powered vehicles have become increasingly popular. As one of the important components in electric vehicles, the battery's application performance, especially high and low temperature performance, has received more and more attention.
对于锂离子电池等电化学设备，温度会减缓内部化学反应，直接或间接影响其安全性、性能和成本，这对于电动汽车和混合动力汽车等至关重要。低温条件下，锂离子电池中正负极中Li +迁移速率降低，电解液与正负极界面的阻抗变大，电解液粘度增大，Li +电导率降低，负极会出现锂金属的析出与沉积。而在高温条件下，电解液会发生分解产生有害气体氟化氢，进而进一步腐蚀电极材料，这些都会影响锂离子电池的电化学性能。 For electrochemical devices such as lithium-ion batteries, temperature can slow down internal chemical reactions, directly or indirectly affecting their safety, performance and cost, which is critical for things like electric and hybrid vehicles. Under low temperature conditions, the migration rate of Li + in the positive and negative electrodes of lithium-ion batteries decreases, the impedance at the interface between the electrolyte and the positive and negative electrodes increases, the viscosity of the electrolyte increases, the conductivity of Li + decreases, and the precipitation and deposition of lithium metal occurs on the negative electrode. Under high temperature conditions, the electrolyte will decompose to produce harmful gas hydrogen fluoride, which will further corrode the electrode materials, all of which will affect the electrochemical performance of lithium-ion batteries.
为了解决这一问题，现有技术中往往采用对正负极材料进行改性的方法。虽然该方法对电池高低温性能有一定程度的改善，但是其制备工艺复杂，且正负极材料种类繁多，不易实现。In order to solve this problem, the method of modifying the positive and negative electrode materials is often used in the prior art. Although this method can improve the high and low temperature performance of the battery to a certain extent, its preparation process is complex and there are many types of positive and negative electrode materials, making it difficult to implement.
有鉴于此，特提出本发明。In view of this, the present invention is proposed.
发明内容Contents of the invention
本发明的第一目的在于提供一种电解液，通过采用特定种类的溶剂，并使电解液中的电解质锂盐的摩尔浓度在特定范围内，能够提高锂离子电池在宽温域包括高温(55℃)和低温(-30℃)条件下的电化学性能。The first object of the present invention is to provide an electrolyte that can improve the performance of lithium-ion batteries in a wide temperature range including high temperatures (55 ℃) and low temperature (-30 ℃) conditions.
本发明的第二目的在于提供一种所述的电解液的制备方法，该制备方法具有操作简单、方便，条件温和，工艺流程短，用时短以及容易大批量生产等优点。The second object of the present invention is to provide a method for preparing the electrolyte, which has the advantages of simple and convenient operation, mild conditions, short process flow, short time and easy mass production.
本发明的第三目的在于提供一种锂离子电池，该锂离子电池通过采用特定的电解液，降低了体系的黏度，有效降低了高低温下的电池内阻，提高了电池高低温下的电化学性能。The third object of the present invention is to provide a lithium-ion battery that uses a specific electrolyte to reduce the viscosity of the system, effectively reduce the internal resistance of the battery under high and low temperatures, and improve the battery's electrical performance under high and low temperatures. chemical properties.
为了实现本发明的上述目的，特采用以下技术方案：In order to achieve the above objects of the present invention, the following technical solutions are adopted:
本发明还提供了一种电解液，所述电解液包括电解质锂盐和溶剂；The invention also provides an electrolyte solution, which includes an electrolyte lithium salt and a solvent;
其中，所述溶剂包括碳酸酯溶剂和/或羧酸酯溶剂；Wherein, the solvent includes carbonate solvent and/or carboxylate solvent;
所述电解液中的电解质锂盐的摩尔浓度为0.5～2mol/L，包括但不限于0.6mol/L、0.7mol/L、0.8mol/L、0.9mol/L、1mol/L、1.1mol/L、1.2mol/L、1.3mol/L、1.4mol/L、1.5mol/L、1.6mol/L、1.7mol/L、1.8mol/L、1.9mol/L中的任意一者的点值或任意两者之间的范围值。其中，所述电解液中的电解质锂盐的摩尔浓度是指所有电解质锂盐的总摩尔浓度。The molar concentration of the electrolyte lithium salt in the electrolyte is 0.5~2mol/L, including but not limited to 0.6mol/L, 0.7mol/L, 0.8mol/L, 0.9mol/L, 1mol/L, 1.1mol/L The point value of any one of L, 1.2mol/L, 1.3mol/L, 1.4mol/L, 1.5mol/L, 1.6mol/L, 1.7mol/L, 1.8mol/L, 1.9mol/L or Any range of values in between. Wherein, the molar concentration of the electrolyte lithium salt in the electrolyte solution refers to the total molar concentration of all electrolyte lithium salts.
本发明通过采用特定种类的溶剂，即采用碳酸酯溶剂和羧酸酯溶剂中的任意一种或这两种的混合，并通过使电解液中的电解质锂盐的摩尔浓度在特定范围内，能够制得适宜于宽温域环境的电解液，有效提高锂离子电池的电化学各项性能，尤其是能够有效提高锂离子电池的电化学循环及倍率性能。The present invention can use a specific type of solvent, that is, use any one of a carbonate solvent and a carboxylate solvent or a mixture of the two, and keep the molar concentration of the electrolyte lithium salt in the electrolyte within a specific range. Preparing an electrolyte suitable for a wide temperature range environment can effectively improve the electrochemical properties of lithium-ion batteries, especially the electrochemical cycle and rate performance of lithium-ion batteries.
优选地，所述溶剂包括所述碳酸酯溶剂和所述羧酸酯溶剂两者的混合，且所述碳酸酯溶剂和所述羧酸酯溶剂的体积比为55～85(包括但不限于52、54、55、56、58、60、62、64、65、67、69、70、72、74、75、78、80、82、83、84中的任意一者的点值或任意两者之间的范围值)：15～45(包括但不限于16、17、18、19、20、22、24、25、27、29、30、32、34、35、37、39、40、41、42、43、44中的任意一者的点值或任意两者之间的范围值)。Preferably, the solvent includes a mixture of the carbonate solvent and the carboxylate solvent, and the volume ratio of the carbonate solvent to the carboxylate solvent is 55 to 85 (including but not limited to 52 , 54, 55, 56, 58, 60, 62, 64, 65, 67, 69, 70, 72, 74, 75, 78, 80, 82, 83, 84 or any two of them Range value between): 15~45 (including but not limited to 16, 17, 18, 19, 20, 22, 24, 25, 27, 29, 30, 32, 34, 35, 37, 39, 40, 41 , 42, 43, 44 any one of the point value or any range value between the two).
通过采用两种不同的特定种类的溶剂，即碳酸酯溶剂和羧酸酯溶剂，并控制碳酸酯溶剂和羧酸酯溶剂的体积比在特定范围内，能够有效降低电解液熔点。并且，引入特定用量的羧酸酯溶剂可以降低电解液黏度，从而有效提高锂离子电池在高低温下的电化学性能。By using two different specific types of solvents, namely carbonate solvent and carboxylate solvent, and controlling the volume ratio of carbonate solvent and carboxylate solvent within a specific range, the melting point of the electrolyte can be effectively reduced. Moreover, the introduction of a specific amount of carboxylate solvent can reduce the viscosity of the electrolyte, thereby effectively improving the electrochemical performance of lithium-ion batteries at high and low temperatures.
优选地，所述碳酸酯溶剂和所述羧酸酯溶剂的体积比为60～80：20～40，例如60：40，或者80：20，或者70：30。Preferably, the volume ratio of the carbonate solvent and the carboxylate solvent is 60-80:20-40, such as 60:40, or 80:20, or 70:30.
优选地，所述碳酸酯溶剂包括碳酸乙烯酯(EC)、碳酸丙烯酯(PC)、碳酸亚乙烯酯(VC)、碳酸二甲酯(DMC)、碳酸二乙酯(DEC)和碳酸甲乙酯(EMC)中的至少一种。Preferably, the carbonate solvent includes ethylene carbonate (EC), propylene carbonate (PC), vinylene carbonate (VC), dimethyl carbonate (DMC), diethyl carbonate (DEC) and methyl ethyl carbonate. At least one of the esters (EMC).
更优选地，所述碳酸酯溶剂包括碳酸乙烯酯、碳酸丙烯酯、碳酸亚乙烯酯、碳酸二甲酯、碳酸二乙酯和碳酸甲乙酯中的至少两种。More preferably, the carbonate solvent includes at least two of ethylene carbonate, propylene carbonate, vinylene carbonate, dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate.
采用至少两种不同种类的碳酸酯溶剂有利于进一步提高电池的循环稳定性能。Using at least two different types of carbonate solvents is beneficial to further improving the cycle stability performance of the battery.
优选地，所述羧酸酯溶剂包括乙酸甲酯(MA)、乙酸乙酯(EA)、丁酸甲酯(MB)、丙酸甲酯(MP)、甲酸甲酯(MF)、丙酸乙酯(EP)、丁酸乙酯(EB)和乙酸正丁酯(BA)中的至少一种。Preferably, the carboxylic acid ester solvent includes methyl acetate (MA), ethyl acetate (EA), methyl butyrate (MB), methyl propionate (MP), methyl formate (MF), ethyl propionate At least one of ester (EP), ethyl butyrate (EB) and n-butyl acetate (BA).
优选地，所述电解液中的电解质锂盐的摩尔浓度为0.9～1.6mol/L，包括但不限于1mol/L、1.1mol/L、1.2mol/L、1.3mol/L、1.4mol/L、1.5mol/L 中的任意一者的点值或任意两者之间的范围值。Preferably, the molar concentration of the electrolyte lithium salt in the electrolyte is 0.9 to 1.6 mol/L, including but not limited to 1 mol/L, 1.1 mol/L, 1.2 mol/L, 1.3 mol/L, and 1.4 mol/L. , 1.5 mol/L or any range value between the two.
更优选地，所述电解液中的电解质锂盐的摩尔浓度为1～1.2mol/L，包括但不限于1.05mol/L、1.1mol/L、1.15mol/L、1.2mol/L中的任意一者的点值或任意两者之间的范围值。More preferably, the molar concentration of the electrolyte lithium salt in the electrolyte is 1 to 1.2 mol/L, including but not limited to any of 1.05 mol/L, 1.1 mol/L, 1.15 mol/L, and 1.2 mol/L. The pip value of one or any range of values in between.
优选地，所述电解质锂盐包括六氟磷酸锂(LiPF 6)、四氟硼酸锂(LiBF 4)、二氟草酸硼酸锂(LiDFOB)、二草酸硼酸锂(LiBOB)、双氟磺酰亚胺锂(LiFSI)和双三氟甲基磺酰亚胺锂(LiTFSI)中的至少一种，更优选为至少两种。 Preferably, the electrolyte lithium salt includes lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium difluoroborate (LiDFOB), lithium dioxaloborate (LiBOB), lithium bisfluorosulfonyl imide (LiFSI ) and lithium bistrifluoromethylsulfonimide (LiTFSI), more preferably at least two.
在本发明一些具体的实施方式中，所述电解质锂盐包括六氟磷酸锂、四氟硼酸锂、二氟草酸硼酸锂、二草酸硼酸锂、双氟磺酰亚胺锂和双三氟甲基磺酰亚胺锂中的两种。例如，所述电解质锂盐选自六氟磷酸锂和四氟硼酸锂；或者，所述电解质锂盐选自六氟磷酸锂和二氟草酸硼酸锂。两种不同种类的所述电解质锂盐分别为第一电解质锂盐和第二电解质锂盐，所述电解液中的所述第一电解质锂盐与所述电解液中的所述第二电解质锂盐的摩尔浓度之比为0.2～0.8：0.2～0.8，还可以选择0.8：0.2、0.6：0.4、0.5：0.5、0.4：0.6或0.2：0.8。In some specific embodiments of the present invention, the electrolyte lithium salt includes lithium hexafluorophosphate, lithium tetrafluoroborate, lithium difluoroxaloborate, lithium dioxaloborate, lithium bisfluorosulfonimide and bistrifluoromethylsulfonimide. Two types of lithium amide. For example, the electrolyte lithium salt is selected from the group consisting of lithium hexafluorophosphate and lithium tetrafluoroborate; or, the electrolyte lithium salt is selected from the group consisting of lithium hexafluorophosphate and lithium difluoroborate. Two different types of electrolyte lithium salts are respectively a first electrolyte lithium salt and a second electrolyte lithium salt. The first electrolyte lithium salt in the electrolyte solution and the second electrolyte lithium salt in the electrolyte solution The molar concentration ratio of salt is 0.2~0.8:0.2~0.8, and you can also choose 0.8:0.2, 0.6:0.4, 0.5:0.5, 0.4:0.6 or 0.2:0.8.
优选地，所述电解液中的所述第一电解质锂盐的摩尔浓度与所述电解液中的所述第二电解质锂盐的摩尔浓度的比为0.8：0.2，或者0.2：0.8，或者0.6：0.4，或者0.4：0.6，或者0.5：0.5。Preferably, the ratio of the molar concentration of the first electrolyte lithium salt in the electrolyte solution to the molar concentration of the second electrolyte lithium salt in the electrolyte solution is 0.8:0.2, or 0.2:0.8, or 0.6 :0.4, or 0.4:0.6, or 0.5:0.5.
在本发明一些具体的实施方式中，所述电解质锂盐包括六氟磷酸锂、四氟硼酸锂、二氟草酸硼酸锂、二草酸硼酸锂、双氟磺酰亚胺锂和双三氟甲基磺酰亚胺锂中的至少三种。In some specific embodiments of the present invention, the electrolyte lithium salt includes lithium hexafluorophosphate, lithium tetrafluoroborate, lithium difluoroxaloborate, lithium dioxaloborate, lithium bisfluorosulfonimide and bistrifluoromethylsulfonimide. At least three of the lithium amines.
优选地，所述电解液还包括添加剂。Preferably, the electrolyte further includes additives.
优选地，所述添加剂包括氟代碳酸乙烯酯、碳酸亚乙烯酯、硫酸乙烯酯、硫酸二甲酯和亚硫酸丁烯酯中的至少一种。Preferably, the additive includes at least one of fluoroethylene carbonate, vinylene carbonate, vinyl sulfate, dimethyl sulfate and butylene sulfite.
本发明通过采用上述种类的添加剂，其能够在电极表面形成稳定存在于有机溶剂中的钝化膜，即SEI膜。这层钝化膜可以有效地避免溶剂分子与电极材料发生过多的副反应，抑制电极的体积膨胀。By using the above-mentioned types of additives, the present invention can form a passivation film that stably exists in an organic solvent on the electrode surface, that is, an SEI film. This passivation film can effectively prevent excessive side reactions between solvent molecules and electrode materials and inhibit the volume expansion of the electrode.
优选地，所述添加剂的质量占所述电解液总质量的0.1％～5.5％。Preferably, the mass of the additive accounts for 0.1% to 5.5% of the total mass of the electrolyte.
采用特定用量的添加剂，有利于进一步提高锂离子电池在高低温下的电化学性能。The use of specific amounts of additives will help further improve the electrochemical performance of lithium-ion batteries at high and low temperatures.
在本发明一些具体的实施方式中，所述电解液制得的锂离子电池在-30℃(零下30℃)的循环保持率大于40％(包括但不限于41％、42％、43％、44％、45％、46％、47％、48％、49％、50％、51％、52％、53％、55％、58％、60％、61％、62％、63％、64％、65％、66％、67％、68％、69％、70％、73％、75％、78％、80％、81％、82％、83％、84％、85％、86％、87％、88％、89％、90％中的任意一者的点值或任意两者之间的范围值)，优选为大于60％，更优选为大于70％，更进一步优选为大于80％，再更进一步优选为大于86％。In some specific embodiments of the present invention, the cycle retention rate of the lithium-ion battery made from the electrolyte at -30°C (minus 30°C) is greater than 40% (including but not limited to 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 55%, 58%, 60%, 61%, 62%, 63%, 64% , 65%, 66%, 67%, 68%, 69%, 70%, 73%, 75%, 78%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87 %, 88%, 89%, 90% or any one of the range values between the two), preferably greater than 60%, more preferably greater than 70%, even more preferably greater than 80%, Even more preferably, it is greater than 86%.
在本发明一些具体的实施方式中，所述电解液制得的锂离子电池在55℃的循环保持率大于50％(包括但不限于51％、52％、53％、54％、55％、56％、57％、58％、59％、60％、61％、62％、63％、64％、65％、66％、67％、68％、69％、70％、71％、72％、73％、75％、78％、80％、81％、82％、83％、84％、85％、86％、87％、88％、89％、90％、91％、92％、93％、94％、95％中的任意一者的点值或任意两者之间的范围值)，优选为大于60％，更优选为大于70％，更进一步优选为大于80％，再更进一步优选为大于88％。In some specific embodiments of the present invention, the cycle retention rate of the lithium-ion battery made from the electrolyte at 55°C is greater than 50% (including but not limited to 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72% ,73%,75%,78%,80%,81%,82%,83%,84%,85%,86%,87%,88%,89%,90%,91%,92%,93 %, 94%, 95% or the range value between any two), preferably greater than 60%, more preferably greater than 70%, further preferably greater than 80%, and still further Preferably it is greater than 88%.
本发明还提供了如上所述的电解液的制备方法，包括以下步骤：The present invention also provides a method for preparing the electrolyte as described above, which includes the following steps:
将电解质锂盐和溶剂混合均匀。Mix the electrolyte lithium salt and solvent evenly.
该制备方法具有操作简单、方便，条件温和，工艺流程短，用时短以及容易大批量生产等优点。The preparation method has the advantages of simple and convenient operation, mild conditions, short process flow, short time and easy mass production.
优选地，在所述将电解质锂盐和溶剂混合均匀后，还包括向其中加入 添加剂，并再次混合均匀的步骤。Preferably, after the electrolyte lithium salt and the solvent are mixed uniformly, the step of adding additives thereto and mixing them uniformly again is also included.
本发明还提供了一种锂离子电池，包括如上所述的电解液，或者，如上所述的电解液的制备方法所制得的电解液。The present invention also provides a lithium ion battery, including the electrolyte solution as described above, or the electrolyte solution prepared by the electrolyte solution preparation method as described above.
该锂离子电池通过采用具有特定组成的电解液，降低了体系的黏度，有效降低了高低温下的电池内阻，提高了电池高低温下的电化学性能。By using an electrolyte with a specific composition, the lithium-ion battery reduces the viscosity of the system, effectively reduces the internal resistance of the battery at high and low temperatures, and improves the electrochemical performance of the battery at high and low temperatures.
在本发明一些具体的实施方式中，所述锂离子电池包括镍钴锰酸锂锂离子电池。In some specific embodiments of the present invention, the lithium ion battery includes a lithium nickel cobalt manganate lithium ion battery.
优选地，所述镍钴锰酸锂锂离子电池包括正极片、隔膜和负极片。Preferably, the lithium nickel cobalt manganate lithium ion battery includes a positive electrode sheet, a separator and a negative electrode sheet.
优选地，所述正极片包括正极集流体和涂覆在所述正极集流体上的正极材料。Preferably, the positive electrode sheet includes a positive electrode current collector and a positive electrode material coated on the positive electrode current collector.
优选地，所述正极集流体上的所述正极材料的涂覆面的直径为10～15mm(还可以选择11mm、12mm、13mm、14mm或14.5mm)，更优选为12mm。Preferably, the diameter of the coated surface of the cathode material on the cathode current collector is 10 to 15 mm (you can also choose 11 mm, 12 mm, 13 mm, 14 mm or 14.5 mm), more preferably 12 mm.
优选地，所述正极材料包括按照质量份数计的如下组分：镍钴锰酸锂75～85份(还可以选择76份、77份、78份、79份、80份、81份、81.5份、82份、82.3份、83份或84份)，导电剂5～15份(还可以选择6份、7份、7.8份、8份、8.9份、9份、10份、11份、11.5份、12份、13份或14份)和粘结剂5～15份(还可以选择6份、7份、7.5份、8份、8.2份、9份、10份、10.6份、11份、11.5份、12份、13份或14份)。Preferably, the cathode material includes the following components in terms of parts by mass: 75 to 85 parts of lithium nickel cobalt manganate (76 parts, 77 parts, 78 parts, 79 parts, 80 parts, 81 parts, 81.5 parts can also be selected) parts, 82 parts, 82.3 parts, 83 parts or 84 parts), 5 to 15 parts of conductive agent (you can also choose 6 parts, 7 parts, 7.8 parts, 8 parts, 8.9 parts, 9 parts, 10 parts, 11 parts, 11.5 parts parts, 12 parts, 13 parts or 14 parts) and 5 to 15 parts of adhesive (you can also choose 6 parts, 7 parts, 7.5 parts, 8 parts, 8.2 parts, 9 parts, 10 parts, 10.6 parts, 11 parts, 11.5 servings, 12 servings, 13 servings or 14 servings).
更优选地，所述正极材料包括按照质量份数计的如下组分：镍钴锰酸锂78～82.5份，导电剂7.4～12.1份和粘结剂7.4～12.1份。More preferably, the positive electrode material includes the following components in parts by mass: 78 to 82.5 parts of lithium nickel cobalt manganate, 7.4 to 12.1 parts of conductive agent, and 7.4 to 12.1 parts of binder.
与现有技术相比，本发明的有益效果为：Compared with the prior art, the beneficial effects of the present invention are:
(1)本发明所提供的电解液，通过采用特定种类的溶剂，并使电解液中的电解质锂盐的摩尔浓度在特定范围内，能够提高锂离子电池在宽温域包括高温(55℃)和低温(-30℃)条件下的电化学性能，有效提高锂离子 电池的电化学循环稳定性能。(1) The electrolyte provided by the present invention can improve the performance of lithium-ion batteries in a wide temperature range, including high temperatures (55°C), by using a specific type of solvent and keeping the molar concentration of the electrolyte lithium salt in the electrolyte within a specific range. and electrochemical performance under low temperature (-30°C) conditions, effectively improving the electrochemical cycle stability performance of lithium-ion batteries.
(2)本发明所提供的电解液，通过采用体积比在特定范围内的碳酸酯溶剂和羧酸酯溶剂，并采用特定用量的添加剂，能够形成优异的SEI膜，从而提升了电导率。并且，引入特定用量的羧酸酯溶剂可以降低电解液黏度，从而进一步提高锂离子电池在高低温下的电化学性能。(2) The electrolyte provided by the present invention can form an excellent SEI film by using a carbonate solvent and a carboxylate solvent with a volume ratio within a specific range and a specific amount of additives, thereby improving the conductivity. Moreover, the introduction of a specific amount of carboxylate solvent can reduce the viscosity of the electrolyte, thereby further improving the electrochemical performance of lithium-ion batteries at high and low temperatures.
(3)本发明所提供的锂离子电池，通过采用特定的电解液，降低了体系的黏度，有效降低了高低温下的电池内阻，提高了电池高低温下的电化学性能。(3) The lithium-ion battery provided by the present invention reduces the viscosity of the system by using a specific electrolyte, effectively reduces the internal resistance of the battery at high and low temperatures, and improves the electrochemical performance of the battery at high and low temperatures.
具体实施方式Detailed ways
下面将结合具体实施方式对本发明的技术方案进行清楚、完整地描述，但是本领域技术人员将会理解，下列所描述的实施例是本发明一部分实施例，而不是全部的实施例，仅用于说明本发明，而不应视为限制本发明的范围。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。实施例中未注明具体条件者，按照常规条件或制造商建议的条件进行。所用试剂或仪器未注明生产厂商者，均为可以通过市售购买获得的常规产品。The technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. However, those skilled in the art will understand that the embodiments described below are some, not all, of the embodiments of the present invention and are only used for illustrative of the invention and should not be construed as limiting the scope of the invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention. If the specific conditions are not specified in the examples, the conditions should be carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not indicated, they are all conventional products that can be purchased commercially.
实施例1Example 1
本实施例提供的电解液由电解质锂盐和溶剂组成。The electrolyte solution provided in this embodiment consists of an electrolyte lithium salt and a solvent.
其中，电解质锂盐为六氟磷酸锂(LiPF 6)。 Among them, the electrolyte lithium salt is lithium hexafluorophosphate (LiPF 6 ).
溶剂为体积比为1：1的碳酸乙烯酯(EC)和碳酸二乙酯(DEC)。The solvent is ethylene carbonate (EC) and diethyl carbonate (DEC) with a volume ratio of 1:1.
电解液中的六氟磷酸锂(LiPF 6)的摩尔浓度为1mol/L。即，电解液中的电解质锂盐的总摩尔浓度为1mol/L。 The molar concentration of lithium hexafluorophosphate (LiPF 6 ) in the electrolyte is 1 mol/L. That is, the total molar concentration of the electrolyte lithium salt in the electrolyte solution is 1 mol/L.
本实施例提供的电解液的制备方法包括以下步骤：将电解质锂盐和溶剂混合均匀，得到电解液。The preparation method of the electrolyte provided in this embodiment includes the following steps: uniformly mixing the electrolyte lithium salt and the solvent to obtain an electrolyte.
实施例2Example 2
本实施例提供的电解液由电解质锂盐和溶剂组成。The electrolyte solution provided in this embodiment consists of an electrolyte lithium salt and a solvent.
其中，电解质锂盐为六氟磷酸锂(LiPF 6)和四氟硼酸锂(LiBF 4)的二者混合。 Among them, the electrolyte lithium salt is a mixture of lithium hexafluorophosphate (LiPF 6 ) and lithium tetrafluoroborate (LiBF 4 ).
溶剂为体积比为1：1的碳酸乙烯酯(EC)和碳酸二乙酯(DEC)。The solvent is ethylene carbonate (EC) and diethyl carbonate (DEC) with a volume ratio of 1:1.
电解液中的六氟磷酸锂(LiPF 6)的摩尔浓度为0.8mol/L，电解液中的四氟硼酸锂(LiBF 4)的摩尔浓度为0.2mol/L。即，电解液中的电解质锂盐的总摩尔浓度为1mol/L。 The molar concentration of lithium hexafluorophosphate (LiPF 6 ) in the electrolyte solution is 0.8 mol/L, and the molar concentration of lithium tetrafluoroborate (LiBF 4 ) in the electrolyte solution is 0.2 mol/L. That is, the total molar concentration of the electrolyte lithium salt in the electrolyte solution is 1 mol/L.
本实施例提供的电解液的制备方法与实施例1相同。The preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 1.
实施例3Example 3
本实施例提供的电解液由电解质锂盐和溶剂组成。The electrolyte solution provided in this embodiment consists of an electrolyte lithium salt and a solvent.
其中，电解质锂盐为六氟磷酸锂(LiPF 6)和四氟硼酸锂(LiBF 4)的二者混合。 Among them, the electrolyte lithium salt is a mixture of lithium hexafluorophosphate (LiPF 6 ) and lithium tetrafluoroborate (LiBF 4 ).
溶剂为体积比为1：1的碳酸乙烯酯(EC)和碳酸二乙酯(DEC)。The solvent is ethylene carbonate (EC) and diethyl carbonate (DEC) with a volume ratio of 1:1.
电解液中的六氟磷酸锂(LiPF 6)的摩尔浓度为0.6mol/L，电解液中的四氟硼酸锂(LiBF 4)的摩尔浓度为0.4mol/L。即，电解液中的电解质锂盐的总摩尔浓度为1mol/L。 The molar concentration of lithium hexafluorophosphate (LiPF 6 ) in the electrolyte solution is 0.6 mol/L, and the molar concentration of lithium tetrafluoroborate (LiBF 4 ) in the electrolyte solution is 0.4 mol/L. That is, the total molar concentration of the electrolyte lithium salt in the electrolyte solution is 1 mol/L.
本实施例提供的电解液的制备方法与实施例1相同。The preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 1.
实施例4Example 4
本实施例提供的电解液由电解质锂盐和溶剂组成。The electrolyte solution provided in this embodiment consists of an electrolyte lithium salt and a solvent.
其中，电解质锂盐为六氟磷酸锂(LiPF 6)和二氟草酸硼酸锂(LiDFOB)的二者混合。 Among them, the electrolyte lithium salt is a mixture of lithium hexafluorophosphate (LiPF 6 ) and lithium difluorooxalate borate (LiDFOB).
溶剂为体积比为1：1的碳酸乙烯酯(EC)和碳酸二乙酯(DEC)。The solvent is ethylene carbonate (EC) and diethyl carbonate (DEC) with a volume ratio of 1:1.
电解液中的六氟磷酸锂(LiPF 6)的摩尔浓度为0.8mol/L，电解液中的二氟草酸硼酸锂(LiDFOB)的摩尔浓度为0.2mol/L。即，电解液中的电解质锂盐的总摩尔浓度为1mol/L。 The molar concentration of lithium hexafluorophosphate (LiPF 6 ) in the electrolyte is 0.8 mol/L, and the molar concentration of lithium difluorooxalate borate (LiDFOB) in the electrolyte is 0.2 mol/L. That is, the total molar concentration of the electrolyte lithium salt in the electrolyte solution is 1 mol/L.
本实施例提供的电解液的制备方法与实施例1相同。The preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 1.
实施例5Example 5
本实施例提供的电解液由电解质锂盐和溶剂组成。The electrolyte solution provided in this embodiment consists of an electrolyte lithium salt and a solvent.
其中，电解质锂盐为六氟磷酸锂(LiPF 6)和二氟草酸硼酸锂(LiDFOB)的二者混合。 Among them, the electrolyte lithium salt is a mixture of lithium hexafluorophosphate (LiPF 6 ) and lithium difluorooxalate borate (LiDFOB).
溶剂为体积比为1：1的碳酸乙烯酯(EC)和碳酸二乙酯(DEC)。The solvent is ethylene carbonate (EC) and diethyl carbonate (DEC) with a volume ratio of 1:1.
电解液中的六氟磷酸锂(LiPF 6)的摩尔浓度为0.6mol/L，电解液中的二氟草酸硼酸锂(LiDFOB)的摩尔浓度为0.4mol/L。即，电解液中的电解质锂盐的总摩尔浓度为1mol/L。 The molar concentration of lithium hexafluorophosphate (LiPF 6 ) in the electrolyte is 0.6 mol/L, and the molar concentration of lithium difluorooxalate borate (LiDFOB) in the electrolyte is 0.4 mol/L. That is, the total molar concentration of the electrolyte lithium salt in the electrolyte solution is 1 mol/L.
本实施例提供的电解液的制备方法与实施例1相同。The preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 1.
实施例6Example 6
本实施例提供的电解液由电解质锂盐和溶剂组成。The electrolyte solution provided in this embodiment consists of an electrolyte lithium salt and a solvent.
其中，电解质锂盐为六氟磷酸锂(LiPF 6)。 Among them, the electrolyte lithium salt is lithium hexafluorophosphate (LiPF 6 ).
溶剂为体积比为3：2(60：40)的碳酸酯溶剂和羧酸酯溶剂，其中，碳酸酯溶剂为体积比为1：1的碳酸乙烯酯(EC)和碳酸二乙酯(DEC)，羧酸酯溶剂为乙酸正丁酯(BA)。The solvent is a carbonate solvent and a carboxylic acid ester solvent with a volume ratio of 3:2 (60:40), wherein the carbonate solvent is ethylene carbonate (EC) and diethyl carbonate (DEC) with a volume ratio of 1:1 , the carboxylate solvent is n-butyl acetate (BA).
电解液中的六氟磷酸锂(LiPF 6)的摩尔浓度为1mol/L。即，电解液中的电解质锂盐的总摩尔浓度为1mol/L。 The molar concentration of lithium hexafluorophosphate (LiPF 6 ) in the electrolyte is 1 mol/L. That is, the total molar concentration of the electrolyte lithium salt in the electrolyte solution is 1 mol/L.
本实施例提供的电解液的制备方法与实施例1相同。The preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 1.
实施例7Example 7
本实施例提供的电解液由电解质锂盐和溶剂组成。The electrolyte solution provided in this embodiment consists of an electrolyte lithium salt and a solvent.
其中，电解质锂盐为六氟磷酸锂(LiPF 6)和四氟硼酸锂(LiBF 4)的二者混合。 Among them, the electrolyte lithium salt is a mixture of lithium hexafluorophosphate (LiPF 6 ) and lithium tetrafluoroborate (LiBF 4 ).
溶剂为体积比为3：2(60：40)的碳酸酯溶剂和羧酸酯溶剂，其中，碳酸酯溶剂为体积比为1：1的碳酸乙烯酯(EC)和碳酸二乙酯(DEC)，羧酸酯溶剂为乙酸正丁酯(BA)。The solvent is a carbonate solvent and a carboxylic acid ester solvent with a volume ratio of 3:2 (60:40), wherein the carbonate solvent is ethylene carbonate (EC) and diethyl carbonate (DEC) with a volume ratio of 1:1 , the carboxylate solvent is n-butyl acetate (BA).
电解液中的六氟磷酸锂(LiPF 6)的摩尔浓度为0.8mol/L，电解液中的四氟硼酸锂(LiBF 4)的摩尔浓度为0.2mol/L。即，电解液中的电解质锂盐的总摩尔浓度为1mol/L。 The molar concentration of lithium hexafluorophosphate (LiPF 6 ) in the electrolyte solution is 0.8 mol/L, and the molar concentration of lithium tetrafluoroborate (LiBF 4 ) in the electrolyte solution is 0.2 mol/L. That is, the total molar concentration of the electrolyte lithium salt in the electrolyte solution is 1 mol/L.
本实施例提供的电解液的制备方法与实施例1相同。The preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 1.
实施例8Example 8
本实施例提供的电解液由电解质锂盐和溶剂组成。The electrolyte solution provided in this embodiment consists of an electrolyte lithium salt and a solvent.
其中，电解质锂盐为六氟磷酸锂(LiPF 6)和二氟草酸硼酸锂(LiDFOB)的二者混合。 Among them, the electrolyte lithium salt is a mixture of lithium hexafluorophosphate (LiPF 6 ) and lithium difluorooxalate borate (LiDFOB).
溶剂为体积比为3：2(60：40)的碳酸酯溶剂和羧酸酯溶剂，其中，碳酸酯溶剂为体积比为1：1的碳酸乙烯酯(EC)和碳酸二乙酯(DEC)，羧酸酯溶剂为乙酸正丁酯(BA)。The solvent is a carbonate solvent and a carboxylic acid ester solvent with a volume ratio of 3:2 (60:40), wherein the carbonate solvent is ethylene carbonate (EC) and diethyl carbonate (DEC) with a volume ratio of 1:1 , the carboxylate solvent is n-butyl acetate (BA).
电解液中的六氟磷酸锂(LiPF 6)的摩尔浓度为0.8mol/L，电解液中的二氟草酸硼酸锂(LiDFOB)的摩尔浓度为0.2mol/L。即，电解液中的电解质锂盐的总摩尔浓度为1mol/L。 The molar concentration of lithium hexafluorophosphate (LiPF 6 ) in the electrolyte is 0.8 mol/L, and the molar concentration of lithium difluorooxalate borate (LiDFOB) in the electrolyte is 0.2 mol/L. That is, the total molar concentration of the electrolyte lithium salt in the electrolyte solution is 1 mol/L.
本实施例提供的电解液的制备方法与实施例1相同。The preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 1.
实施例9Example 9
本实施例提供的电解液由电解质锂盐和溶剂组成。The electrolyte solution provided in this embodiment consists of an electrolyte lithium salt and a solvent.
其中，电解质锂盐为六氟磷酸锂(LiPF 6)和四氟硼酸锂(LiBF 4)的二 者混合。 Among them, the electrolyte lithium salt is a mixture of lithium hexafluorophosphate (LiPF 6 ) and lithium tetrafluoroborate (LiBF 4 ).
溶剂为体积比为4：1(80：20)的碳酸酯溶剂和羧酸酯溶剂，其中，碳酸酯溶剂为体积比为1：1的碳酸乙烯酯(EC)和碳酸二乙酯(DEC)，羧酸酯溶剂为乙酸正丁酯(BA)。The solvent is a carbonate solvent and a carboxylic acid ester solvent with a volume ratio of 4:1 (80:20), wherein the carbonate solvent is ethylene carbonate (EC) and diethyl carbonate (DEC) with a volume ratio of 1:1 , the carboxylate solvent is n-butyl acetate (BA).
电解液中的六氟磷酸锂(LiPF 6)的摩尔浓度为0.8mol/L，电解液中的四氟硼酸锂(LiBF 4)的摩尔浓度为0.2mol/L。即，电解液中的电解质锂盐的总摩尔浓度为1mol/L。 The molar concentration of lithium hexafluorophosphate (LiPF 6 ) in the electrolyte solution is 0.8 mol/L, and the molar concentration of lithium tetrafluoroborate (LiBF 4 ) in the electrolyte solution is 0.2 mol/L. That is, the total molar concentration of the electrolyte lithium salt in the electrolyte solution is 1 mol/L.
本实施例提供的电解液的制备方法与实施例1相同。The preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 1.
实施例10Example 10
本实施例提供的电解液由电解质锂盐和溶剂组成。The electrolyte solution provided in this embodiment consists of an electrolyte lithium salt and a solvent.
其中，电解质锂盐为六氟磷酸锂(LiPF 6)和二氟草酸硼酸锂(LiDFOB)的二者混合。 Among them, the electrolyte lithium salt is a mixture of lithium hexafluorophosphate (LiPF 6 ) and lithium difluorooxalate borate (LiDFOB).
溶剂为体积比为4：1(80：20)的碳酸酯溶剂和羧酸酯溶剂，其中，碳酸酯溶剂为体积比为1：1的碳酸乙烯酯(EC)和碳酸二乙酯(DEC)，羧酸酯溶剂为乙酸正丁酯(BA)。The solvent is a carbonate solvent and a carboxylic acid ester solvent with a volume ratio of 4:1 (80:20), wherein the carbonate solvent is ethylene carbonate (EC) and diethyl carbonate (DEC) with a volume ratio of 1:1 , the carboxylate solvent is n-butyl acetate (BA).
电解液中的六氟磷酸锂(LiPF 6)的摩尔浓度为0.8mol/L，电解液中的二氟草酸硼酸锂(LiDFOB)的摩尔浓度为0.2mol/L。即，电解液中的电解质锂盐的总摩尔浓度为1mol/L。 The molar concentration of lithium hexafluorophosphate (LiPF 6 ) in the electrolyte is 0.8 mol/L, and the molar concentration of lithium difluorooxalate borate (LiDFOB) in the electrolyte is 0.2 mol/L. That is, the total molar concentration of the electrolyte lithium salt in the electrolyte solution is 1 mol/L.
本实施例提供的电解液的制备方法与实施例1相同。The preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 1.
实施例11Example 11
本实施例提供的电解液由电解质锂盐、溶剂和添加剂组成。The electrolyte provided in this embodiment consists of electrolyte lithium salt, solvent and additives.
其中，电解质锂盐为六氟磷酸锂(LiPF 6)。 Among them, the electrolyte lithium salt is lithium hexafluorophosphate (LiPF 6 ).
溶剂为体积比为4：1(80：20)的碳酸酯溶剂和羧酸酯溶剂，其中，碳酸酯溶剂为体积比为1：1的碳酸乙烯酯(EC)和碳酸二乙酯(DEC)， 羧酸酯溶剂为乙酸正丁酯(BA)。The solvent is a carbonate solvent and a carboxylic acid ester solvent with a volume ratio of 4:1 (80:20), wherein the carbonate solvent is ethylene carbonate (EC) and diethyl carbonate (DEC) with a volume ratio of 1:1 , the carboxylate solvent is n-butyl acetate (BA).
电解液中的六氟磷酸锂(LiPF 6)的摩尔浓度为1mol/L。即，电解液中的电解质锂盐的总摩尔浓度为1mol/L。 The molar concentration of lithium hexafluorophosphate (LiPF 6 ) in the electrolyte is 1 mol/L. That is, the total molar concentration of the electrolyte lithium salt in the electrolyte solution is 1 mol/L.
添加剂为硫酸乙烯酯(DTD)。DTD的质量占电解液总质量的0.5％。The additive is vinyl sulfate (DTD). The mass of DTD accounts for 0.5% of the total mass of the electrolyte.
本实施例提供的电解液的制备方法包括以下步骤：将电解质锂盐和溶剂混合均匀后，向其中加入添加剂，再次混合均匀后，得到电解液。The preparation method of the electrolyte provided in this embodiment includes the following steps: after mixing the electrolyte lithium salt and the solvent uniformly, adding additives thereto, and mixing uniformly again to obtain the electrolyte solution.
实施例12Example 12
本实施例提供的电解液由电解质锂盐、溶剂和添加剂组成。The electrolyte provided in this embodiment consists of electrolyte lithium salt, solvent and additives.
其中，电解质锂盐为六氟磷酸锂(LiPF 6)和四氟硼酸锂(LiBF 4)的二者混合。 Among them, the electrolyte lithium salt is a mixture of lithium hexafluorophosphate (LiPF 6 ) and lithium tetrafluoroborate (LiBF 4 ).
溶剂为体积比为4：1(80：20)的碳酸酯溶剂和羧酸酯溶剂，其中，碳酸酯溶剂为体积比为1：1的碳酸乙烯酯(EC)和碳酸二乙酯(DEC)，羧酸酯溶剂为乙酸正丁酯(BA)。The solvent is a carbonate solvent and a carboxylic acid ester solvent with a volume ratio of 4:1 (80:20), wherein the carbonate solvent is ethylene carbonate (EC) and diethyl carbonate (DEC) with a volume ratio of 1:1 , the carboxylate solvent is n-butyl acetate (BA).
电解液中的六氟磷酸锂(LiPF 6)的摩尔浓度为0.8mol/L，电解液中的四氟硼酸锂(LiBF 4)的摩尔浓度为0.2mol/L。即，电解液中的电解质锂盐的总摩尔浓度为1mol/L。 The molar concentration of lithium hexafluorophosphate (LiPF 6 ) in the electrolyte solution is 0.8 mol/L, and the molar concentration of lithium tetrafluoroborate (LiBF 4 ) in the electrolyte solution is 0.2 mol/L. That is, the total molar concentration of the electrolyte lithium salt in the electrolyte solution is 1 mol/L.
添加剂为硫酸乙烯酯(DTD)。DTD的质量占电解液总质量的1％。The additive is vinyl sulfate (DTD). The mass of DTD accounts for 1% of the total mass of the electrolyte.
本实施例提供的电解液的制备方法与实施例11相同。The preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 11.
实施例13Example 13
本实施例提供的电解液由电解质锂盐、溶剂和添加剂组成。The electrolyte provided in this embodiment consists of electrolyte lithium salt, solvent and additives.
其中，电解质锂盐为六氟磷酸锂(LiPF 6)和二氟草酸硼酸锂(LiDFOB)的二者混合。 Among them, the electrolyte lithium salt is a mixture of lithium hexafluorophosphate (LiPF 6 ) and lithium difluorooxalate borate (LiDFOB).
溶剂为体积比为4：1(80：20)的碳酸酯溶剂和羧酸酯溶剂，其中，碳酸酯溶剂为体积比为1：1的碳酸乙烯酯(EC)和碳酸二乙酯(DEC)， 羧酸酯溶剂为乙酸正丁酯(BA)。The solvent is a carbonate solvent and a carboxylic acid ester solvent with a volume ratio of 4:1 (80:20), wherein the carbonate solvent is ethylene carbonate (EC) and diethyl carbonate (DEC) with a volume ratio of 1:1 , the carboxylate solvent is n-butyl acetate (BA).
电解液中的六氟磷酸锂(LiPF 6)的摩尔浓度为0.8mol/L，电解液中的二氟草酸硼酸锂(LiDFOB)的摩尔浓度为0.2mol/L。即，电解液中的电解质锂盐的总摩尔浓度为1mol/L。 The molar concentration of lithium hexafluorophosphate (LiPF 6 ) in the electrolyte is 0.8 mol/L, and the molar concentration of lithium difluorooxalate borate (LiDFOB) in the electrolyte is 0.2 mol/L. That is, the total molar concentration of the electrolyte lithium salt in the electrolyte solution is 1 mol/L.
添加剂为硫酸乙烯酯(DTD)。DTD的质量占电解液总质量的1％。The additive is vinyl sulfate (DTD). The mass of DTD accounts for 1% of the total mass of the electrolyte.
本实施例提供的电解液的制备方法与实施例11相同。The preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 11.
实施例14Example 14
本实施例提供的电解液的组成与实施例12基本相同，区别仅在于，DTD的质量占电解液总质量的3％。The composition of the electrolyte provided in this embodiment is basically the same as that in Embodiment 12, and the only difference is that the mass of DTD accounts for 3% of the total mass of the electrolyte.
本实施例提供的电解液的制备方法与实施例11相同。The preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 11.
实施例15Example 15
本实施例提供的电解液的组成与实施例13基本相同，区别仅在于，DTD的质量占电解液总质量的3％。The composition of the electrolyte provided in this embodiment is basically the same as that in Embodiment 13, and the only difference is that the mass of DTD accounts for 3% of the total mass of the electrolyte.
本实施例提供的电解液的制备方法与实施例11相同。The preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 11.
实施例16Example 16
本实施例提供的电解液的组成与实施例12基本相同，区别仅在于，DTD的质量占电解液总质量的5％。The composition of the electrolyte provided in this embodiment is basically the same as that in Embodiment 12, and the only difference is that the mass of DTD accounts for 5% of the total mass of the electrolyte.
本实施例提供的电解液的制备方法与实施例11相同。The preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 11.
实施例17Example 17
本实施例提供的电解液的组成与实施例13基本相同，区别仅在于，DTD的质量占电解液总质量的5％。The composition of the electrolyte provided in this embodiment is basically the same as that in Embodiment 13, and the only difference is that the mass of DTD accounts for 5% of the total mass of the electrolyte.
本实施例提供的电解液的制备方法与实施例11相同。The preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 11.
实施例18Example 18
本实施例提供的电解液由电解质锂盐、溶剂和添加剂组成。The electrolyte provided in this embodiment consists of electrolyte lithium salt, solvent and additives.
其中，电解质锂盐为二草酸硼酸锂(LiBOB)和双氟磺酰亚胺锂(LiFSI)的二者混合。Among them, the electrolyte lithium salt is a mixture of lithium dioxaloborate (LiBOB) and lithium bisfluorosulfonimide (LiFSI).
溶剂为体积比为4：1(80：20)的碳酸酯溶剂和羧酸酯溶剂，其中，碳酸酯溶剂为体积比为1：1的碳酸甲乙酯(EMC)和碳酸亚乙烯酯(VC)，羧酸酯溶剂为丙酸甲酯(MP)。The solvent is a carbonate solvent and a carboxylic acid ester solvent with a volume ratio of 4:1 (80:20). The carbonate solvent is ethyl methyl carbonate (EMC) and vinylene carbonate (VC) with a volume ratio of 1:1. ), the carboxylate solvent is methyl propionate (MP).
电解液中的二草酸硼酸锂(LiBOB)的摩尔浓度为0.6mol/L，电解液中的双氟磺酰亚胺锂(LiFSI)的摩尔浓度为0.6mol/L。即，电解液中的电解质锂盐的总摩尔浓度为1.2mol/L。The molar concentration of lithium dioxaloborate (LiBOB) in the electrolyte is 0.6 mol/L, and the molar concentration of lithium bisfluorosulfonimide (LiFSI) in the electrolyte is 0.6 mol/L. That is, the total molar concentration of the electrolyte lithium salt in the electrolyte solution is 1.2 mol/L.
添加剂为硫酸乙烯酯(DTD)。DTD的质量占电解液总质量的1％。The additive is vinyl sulfate (DTD). The mass of DTD accounts for 1% of the total mass of the electrolyte.
本实施例提供的电解液的制备方法与实施例11相同。The preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 11.
实施例19Example 19
本实施例提供的电解液由电解质锂盐、溶剂和添加剂组成。The electrolyte provided in this embodiment consists of electrolyte lithium salt, solvent and additives.
其中，电解质锂盐为二草酸硼酸锂(LiBOB)、二氟草酸硼酸锂(LiDFOB)和双三氟甲基磺酰亚胺锂(LiTFSI)的三者混合。Among them, the electrolyte lithium salt is a mixture of lithium dioxaloborate (LiBOB), lithium difluorooxaloborate (LiDFOB) and lithium bistrifluoromethylsulfonyl imide (LiTFSI).
溶剂为体积比为4：1(80：20)的碳酸酯溶剂和羧酸酯溶剂，其中，碳酸酯溶剂为体积比为1：1的碳酸二甲酯(DMC)和碳酸亚乙烯酯(VC)，羧酸酯溶剂为乙酸正丁酯(BA)。The solvent is a carbonate solvent and a carboxylate solvent with a volume ratio of 4:1 (80:20). The carbonate solvent is dimethyl carbonate (DMC) and vinylene carbonate (VC) with a volume ratio of 1:1. ), the carboxylate solvent is n-butyl acetate (BA).
电解液中的二草酸硼酸锂(LiBOB)的摩尔浓度为1mol/L，电解液中的二氟草酸硼酸锂(LiDFOB)的摩尔浓度为0.3mol/L，电解液中的双三氟甲基磺酰亚胺锂(LiTFSI)的摩尔浓度为0.3mol/L。即，电解液中的电解质锂盐的总摩尔浓度为1.6mol/L。The molar concentration of lithium dioxaloborate (LiBOB) in the electrolyte is 1mol/L, the molar concentration of lithium difluoroxaloborate (LiDFOB) in the electrolyte is 0.3mol/L, and the molar concentration of bistrifluoromethylsulfonate in the electrolyte is The molar concentration of lithium imide (LiTFSI) is 0.3mol/L. That is, the total molar concentration of the electrolyte lithium salt in the electrolyte solution is 1.6 mol/L.
添加剂为碳酸亚乙烯酯(VC)。VC的质量占电解液总质量的1％。The additive is vinylene carbonate (VC). The mass of VC accounts for 1% of the total mass of the electrolyte.
本实施例提供的电解液的制备方法与实施例11相同。The preparation method of the electrolyte provided in this embodiment is the same as that in Embodiment 11.
对比例1Comparative example 1
本对比例提供的电解液的组成与实施例16基本相同，区别仅在于，将添加剂硫酸乙烯酯(DTD)替换为氟代碳酸乙烯酯(FEC)，但保持其用量不变(即FEC的质量占电解液总质量的5％)。The composition of the electrolyte provided in this comparative example is basically the same as that in Example 16. The only difference is that the additive vinyl sulfate (DTD) is replaced by fluoroethylene carbonate (FEC), but its dosage remains unchanged (that is, the mass of FEC 5% of the total mass of the electrolyte).
本对比例提供的电解液的制备方法与实施例16相同。The preparation method of the electrolyte provided in this comparative example is the same as that in Example 16.
对比例2Comparative example 2
本对比例提供的电解液的组成与实施例17基本相同，区别仅在于，将添加剂硫酸乙烯酯(DTD)替换为氟代碳酸乙烯酯(FEC)，但保持其用量不变(即FEC的质量占电解液总质量的5％)。The composition of the electrolyte provided in this comparative example is basically the same as that in Example 17. The only difference is that the additive vinyl sulfate (DTD) is replaced by fluoroethylene carbonate (FEC), but its dosage remains unchanged (that is, the mass of FEC 5% of the total mass of the electrolyte).
本对比例提供的电解液的制备方法与实施例17相同。The preparation method of the electrolyte provided in this comparative example is the same as that in Example 17.
对比例3Comparative example 3
本对比例提供的电解液的组成与实施例17基本相同，区别仅在于，将电解液中的六氟磷酸锂(LiPF 6)的摩尔浓度替换为2mol/L，并将电解液中的二氟草酸硼酸锂(LiDFOB)的摩尔浓度替换为0.5mol/L。即，电解液中的电解质锂盐的总摩尔浓度为2.5mol/L。 The composition of the electrolyte provided in this comparative example is basically the same as that in Example 17. The only difference is that the molar concentration of lithium hexafluorophosphate (LiPF 6 ) in the electrolyte is replaced with 2 mol/L, and the lithium difluoroxalate borate in the electrolyte is replaced. The molar concentration of (LiDFOB) was replaced with 0.5 mol/L. That is, the total molar concentration of the electrolyte lithium salt in the electrolyte solution is 2.5 mol/L.
本对比例提供的电解液的制备方法与实施例17相同。The preparation method of the electrolyte provided in this comparative example is the same as that in Example 17.
对比例4Comparative example 4
本对比例提供的电解液的组成与实施例17基本相同，区别仅在于，将碳酸酯溶剂和羧酸酯溶剂的体积比为替换为1：4(即溶剂为体积比为1：4(20：80)的碳酸酯溶剂和羧酸酯溶剂，而碳酸酯溶剂仍为体积比为1：1的碳酸乙烯酯和碳酸二乙酯，羧酸酯溶剂仍为乙酸正丁酯)。The composition of the electrolyte provided in this comparative example is basically the same as that in Example 17. The only difference is that the volume ratio of the carbonate solvent and the carboxylate solvent is replaced by 1:4 (that is, the volume ratio of the solvent is 1:4 (20 :80) carbonate solvent and carboxylate solvent, while the carbonate solvent is still ethylene carbonate and diethyl carbonate with a volume ratio of 1:1, and the carboxylate solvent is still n-butyl acetate).
本对比例提供的电解液的制备方法与实施例17相同。The preparation method of the electrolyte provided in this comparative example is the same as that in Example 17.
对比例5Comparative example 5
本对比例提供的电解液的组成与实施例17基本相同，区别仅在于，DTD 的质量占电解液总质量的7％。The composition of the electrolyte provided in this comparative example is basically the same as that in Example 17, and the only difference is that the mass of DTD accounts for 7% of the total mass of the electrolyte.
本对比例提供的电解液的制备方法与实施例17相同。The preparation method of the electrolyte provided in this comparative example is the same as that in Example 17.
实验例1Experimental example 1
对以上各实施例和各对比例的电解液装配得到的电池进行宽温域条件下的电化学性能测试：-30℃以及55℃，经过0.2C充电和0.5C放电，循环150圈记录容量保持率。结果如下表1所示(表1中的M即mol/L)。The batteries assembled with the electrolytes of each of the above embodiments and comparative examples were tested for electrochemical performance under wide temperature range conditions: -30°C and 55°C, after 0.2C charging and 0.5C discharging, recording capacity retention after 150 cycles. Rate. The results are shown in Table 1 below (M in Table 1 is mol/L).
表1 各组电解液的组成以及各组电池的循环保持率Table 1 The composition of the electrolyte of each group and the cycle retention rate of each group of batteries
Figure PCTCN2022141937-appb-000001
Figure PCTCN2022141937-appb-000001
Figure PCTCN2022141937-appb-000002
Figure PCTCN2022141937-appb-000002
Figure PCTCN2022141937-appb-000003
Figure PCTCN2022141937-appb-000003
从表1可以看出，本发明通过采用体积比在特定范围内的碳酸酯溶剂和羧酸酯溶剂，并采用特定用量的添加剂，能够形成优异的SEI膜，从而提升了电池循环保持率以及平均库伦效率，有效提高了锂离子电池在高低温下的电化学性能。As can be seen from Table 1, the present invention can form an excellent SEI film by using a carbonate solvent and a carboxylate solvent with a volume ratio within a specific range, and using a specific amount of additives, thereby improving the battery cycle retention rate and average Coulombic efficiency effectively improves the electrochemical performance of lithium-ion batteries at high and low temperatures.
通过比较实施例16和对比例1、实施例17和对比例2的实验结果可以看出，当用氟代碳酸乙烯酯(FEC)替换电解液的添加剂硫酸乙烯酯(DTD)后，锂离子电池的高低温循环性能变差。这就说明，本发明所提供的特定种类的添加剂，能够显著提高锂离子电池在高低温下的电化学性能。By comparing the experimental results of Example 16 with Comparative Example 1, Example 17 and Comparative Example 2, it can be seen that when the additive vinyl sulfate (DTD) of the electrolyte is replaced with fluoroethylene carbonate (FEC), the lithium-ion battery The high and low temperature cycle performance deteriorates. This shows that the specific types of additives provided by the present invention can significantly improve the electrochemical performance of lithium-ion batteries at high and low temperatures.
通过比较实施例17以及对比例3、对比例4和对比例5的实验结果可以看出，电解液中的电解质锂盐的总摩尔浓度、碳酸酯溶剂和羧酸酯溶剂的体积比以及添加剂的用量，均会对电池高低温下的电化学性能产生较大影响。而采用本发明所提供的参数范围能够获得更加优异的电化学性能。By comparing the experimental results of Example 17 and Comparative Examples 3, 4 and 5, it can be seen that the total molar concentration of the electrolyte lithium salt in the electrolyte solution, the volume ratio of the carbonate solvent and the carboxylate solvent, and the The dosage will have a great impact on the electrochemical performance of the battery under high and low temperatures. By adopting the parameter range provided by the present invention, more excellent electrochemical performance can be obtained.
尽管已用具体实施例来说明和描述了本发明，然而应意识到，以上各实施例仅用以说明本发明的技术方案，而非对其限制；本领域的普通技术人员应当理解：在不背离本发明的精神和范围的情况下，可以对前述各实施例所记载的技术方案进行修改，或者对其中部分或者全部技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本发明各实施例技术方案的范围；因此，这意味着在所附权利要求中包括属于本发明范围内的所有这些替换和修改。Although the present invention has been illustrated and described with specific embodiments, it should be realized that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit it; those of ordinary skill in the art should understand that: Without departing from the spirit and scope of the present invention, the technical solutions described in the foregoing embodiments may be modified, or some or all of the technical features thereof may be equivalently substituted; however, these modifications or substitutions shall not make the corresponding technical solutions essentially depart from the scope of the technical solutions of the various embodiments of the present invention; therefore, it is meant that all such substitutions and modifications falling within the scope of the present invention are included in the appended claims.

Claims (10)

  1. 一种电解液，其特征在于，所述电解液包括电解质锂盐和溶剂；An electrolyte solution, characterized in that the electrolyte solution includes an electrolyte lithium salt and a solvent;
    其中，所述溶剂包括碳酸酯溶剂和/或羧酸酯溶剂；Wherein, the solvent includes carbonate solvent and/or carboxylate solvent;
    所述电解液中的电解质锂盐的摩尔浓度为0.5～2mol/L。The molar concentration of the electrolyte lithium salt in the electrolyte solution is 0.5-2 mol/L.
  2. 根据权利要求1所述的电解液，其特征在于，所述溶剂包括所述碳酸酯溶剂和所述羧酸酯溶剂两者的混合，且所述碳酸酯溶剂和所述羧酸酯溶剂的体积比为55～85：15～45；The electrolyte of claim 1, wherein the solvent includes a mixture of the carbonate solvent and the carboxylate solvent, and the volumes of the carbonate solvent and the carboxylate solvent are The ratio is 55~85:15~45;
    优选地，所述碳酸酯溶剂和所述羧酸酯溶剂的体积比为60～80：20～40。Preferably, the volume ratio of the carbonate solvent and the carboxylate solvent is 60-80:20-40.
  3. 根据权利要求1所述的电解液，其特征在于，所述碳酸酯溶剂包括碳酸乙烯酯、碳酸丙烯酯、碳酸亚乙烯酯、碳酸二甲酯、碳酸二乙酯和碳酸甲乙酯中的至少一种；The electrolyte solution according to claim 1, wherein the carbonate solvent includes at least one of ethylene carbonate, propylene carbonate, vinylene carbonate, dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate. A sort of;
    优选地，所述碳酸酯溶剂包括碳酸乙烯酯、碳酸丙烯酯、碳酸亚乙烯酯、碳酸二甲酯、碳酸二乙酯和碳酸甲乙酯中的至少两种。Preferably, the carbonate solvent includes at least two of ethylene carbonate, propylene carbonate, vinylene carbonate, dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate.
  4. 根据权利要求1所述的电解液，其特征在于，所述羧酸酯溶剂包括乙酸甲酯、乙酸乙酯、丁酸甲酯、丙酸甲酯、甲酸甲酯、丙酸乙酯、丁酸乙酯和乙酸正丁酯中的至少一种。The electrolyte according to claim 1, wherein the carboxylic acid ester solvent includes methyl acetate, ethyl acetate, methyl butyrate, methyl propionate, methyl formate, ethyl propionate, butyric acid At least one of ethyl ester and n-butyl acetate.
  5. 根据权利要求1所述的电解液，其特征在于，所述电解液中的电解质锂盐的摩尔浓度为0.9～1.6mol/L，优选为1～1.2mol/L；The electrolyte solution according to claim 1, characterized in that the molar concentration of the electrolyte lithium salt in the electrolyte solution is 0.9-1.6 mol/L, preferably 1-1.2 mol/L;
    优选地，所述电解质锂盐包括六氟磷酸锂、四氟硼酸锂、二氟草酸硼酸锂、二草酸硼酸锂、双氟磺酰亚胺锂和双三氟甲基磺酰亚胺锂中的至少一种，更优选为至少两种。Preferably, the electrolyte lithium salt includes at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium difluoroxaloborate, lithium dioxaloborate, lithium bisfluorosulfonyl imide and lithium bistrifluoromethylsulfonyl imide. , more preferably at least two.
  6. 根据权利要求1～5任一项所述的电解液，其特征在于，所述电解液还包括添加剂；The electrolyte solution according to any one of claims 1 to 5, characterized in that the electrolyte solution further includes additives;
    优选地，所述添加剂包括氟代碳酸乙烯酯、碳酸亚乙烯酯、硫酸乙烯酯、硫酸二甲酯和亚硫酸丁烯酯中的至少一种。Preferably, the additive includes at least one of fluoroethylene carbonate, vinylene carbonate, vinyl sulfate, dimethyl sulfate and butylene sulfite.
  7. 根据权利要求6所述的电解液，其特征在于，所述添加剂的质量占所述电解液总质量的0.1％～5.5％。The electrolyte solution according to claim 6, characterized in that the mass of the additive accounts for 0.1% to 5.5% of the total mass of the electrolyte solution.
  8. 如权利要求1～7任一项所述的电解液的制备方法，其特征在于，包括以下步骤：The preparation method of electrolyte solution according to any one of claims 1 to 7, characterized in that it includes the following steps:
    将电解质锂盐和溶剂混合均匀。Mix the electrolyte lithium salt and solvent evenly.
  9. 根据权利要求8所述的电解液的制备方法，其特征在于，在所述将电解质锂盐和溶剂混合均匀后，还包括向其中加入添加剂的步骤。The method for preparing an electrolyte according to claim 8, further comprising the step of adding an additive to the electrolyte lithium salt and the solvent after the electrolyte lithium salt and the solvent are uniformly mixed.
  10. 一种锂离子电池，包括如权利要求1～7任一项所述的电解液，或者，如权利要求8或9所述的电解液的制备方法所制得的电解液。A lithium ion battery, including the electrolyte according to any one of claims 1 to 7, or the electrolyte prepared by the method for preparing the electrolyte according to claim 8 or 9.
PCT/CN2022/141937 2022-06-07 2022-12-26 Electrolyte solution and preparation method therefor, and lithium-ion battery WO2023236510A1 (en)

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