WO2023097658A1 - 一种电化学装置及电子装置 - Google Patents

一种电化学装置及电子装置 Download PDF

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WO2023097658A1
WO2023097658A1 PCT/CN2021/135355 CN2021135355W WO2023097658A1 WO 2023097658 A1 WO2023097658 A1 WO 2023097658A1 CN 2021135355 W CN2021135355 W CN 2021135355W WO 2023097658 A1 WO2023097658 A1 WO 2023097658A1
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electrolyte
lithium
electrochemical device
carbonate
mass percentage
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PCT/CN2021/135355
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English (en)
French (fr)
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刘建禹
龙海
唐超
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宁德新能源科技有限公司
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Priority to PCT/CN2021/135355 priority Critical patent/WO2023097658A1/zh
Priority to CN202180028388.4A priority patent/CN115428220A/zh
Priority to EP21966085.9A priority patent/EP4443584A1/en
Publication of WO2023097658A1 publication Critical patent/WO2023097658A1/zh
Priority to US18/731,804 priority patent/US20240322234A1/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
    • 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
    • H01M10/05—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
    • H01M10/056—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
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic electrolyte
    • H01M2300/0028—Organic electrolyte characterised by the solvent
    • H01M2300/0034—Fluorinated solvents
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic electrolyte
    • H01M2300/0028—Organic electrolyte characterised by the solvent
    • H01M2300/0037—Mixture of solvents
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application relates to the field of electrochemical technology, in particular to an electrochemical device and an electronic device.
  • the purpose of the present application is to provide an electrochemical device and an electronic device to improve the cycle performance of the electrochemical device.
  • the specific technical scheme is as follows:
  • the first aspect of the present application provides an electrochemical device, which includes a positive electrode, a negative electrode, a separator, and an electrolyte, wherein the electrolyte includes fluoroethylene carbonate and a trinitrile compound.
  • the mass percentage of fluoroethylene carbonate is A%, 4 ⁇ A ⁇ 10, for example, A can be 4, 5, 6, 7, 8, 9, 10 or between Any range;
  • the mass percentage of the trinitrile compound is B%, 1 ⁇ B ⁇ 3, for example, B can be 1, 1.5, 2, 2.5, 3 or any range therebetween.
  • Described positive pole comprises positive pole active material, and described positive pole active material comprises metal element M, and metal element M comprises at least one in Ti, Mg or Al, and the content of metal element M in positive pole active material is C ppm, C and B Satisfies: 7 ⁇ C ⁇ B/1000 ⁇ 27, for example, C ⁇ B/1000 can be 7, 10, 13, 15, 18, 20, 22, 25, 27 or any range therebetween.
  • the positive electrode may refer to the positive electrode sheet, and the negative electrode may refer to the negative electrode sheet.
  • the inventors of the present application found that by adjusting A, B and C ⁇ B/1000 within the above range, the high-temperature cycle performance and float charge performance of the lithium-ion battery can be improved. Without being limited to any theory, it may be that the structural stability of the positive electrode can be improved when the metal element M is included in the positive electrode active material, but the structural stability of the negative electrode also needs to be improved, so that the overall kinetic performance of the lithium-ion battery is improved.
  • the application improves the film-forming stability of the negative electrode by adjusting the content of fluoroethylene carbonate in the electrolyte, and improves the high-temperature cycle performance of lithium-ion batteries by adjusting the content of trinitrile compounds in the electrolyte, so that lithium-ion
  • the battery has good high temperature cycle performance and float charge performance.
  • the relationship between A and B satisfies: 6 ⁇ A ⁇ B ⁇ 22, for example, A ⁇ B can be 6, 8, 10, 12, 15, 17, 20, 22 or between any range.
  • a ⁇ B can be 6, 8, 10, 12, 15, 17, 20, 22 or between any range.
  • the defect degree of the negative electrode is Id/Ig, satisfying: 0.13 ⁇ Id/Ig ⁇ 0.3.
  • the relationship between Id/Ig and A satisfies: 6 ⁇ A ⁇ (10 ⁇ Id/Ig) ⁇ 24.
  • Id/Ig can be 0.13, 0.15, 0.2, 0.25, 0.3 or any range therebetween, and A ⁇ (10 ⁇ Id/Ig) can be 6, 8, 9, 10, 12, 15, 17, 29, 20, 22, 24 or any range therebetween.
  • a ⁇ (10 ⁇ Id/Ig) is too small (such as less than 6), the kinetic performance of the negative electrode side will be insufficient, side reactions will increase, and the cycle stability of lithium-ion batteries will deteriorate; A ⁇ (10 ⁇ Id/Ig ) is too large (for example, greater than 24), the high temperature stability of lithium-ion batteries will be affected.
  • Id refers to the D peak peak intensity in the Raman spectrum of the negative electrode active material
  • Ig refers to the G peak peak intensity in the Raman spectrum of the negative pole active material
  • Id/Ig represents the negative pole
  • the relationship between C and Id/Ig satisfies: 6 ⁇ C/(3000 ⁇ Id/Ig) ⁇ 20.
  • C/(3000 ⁇ Id/Ig) may be 6, 7, 10, 12, 15, 18, 20 or any range therebetween.
  • C/(3000 ⁇ Id/Ig) may be 6, 7, 10, 12, 15, 18, 20 or any range therebetween.
  • the electrolytic solution further includes a dinitrile compound, and based on the mass of the electrolytic solution, the mass percentage of the dinitrile compound is F%, and 1 ⁇ F ⁇ 3.
  • F can be 1, 1.5, 2, 2.5, 3 or any range therebetween.
  • the dinitrile compound content is too low (for example, less than 1%)
  • the protective effect to the positive electrode is not obvious
  • the dinitrile compound content is too high (for example, higher than 3%)
  • the viscosity thus increases the internal resistance of the lithium-ion battery.
  • the content of the dinitrile compound within the above range, the high-temperature cycle performance and float charge performance of the lithium-ion battery can be further improved.
  • the relationship between F and B satisfies: 2 ⁇ F+B ⁇ 6.
  • F+B can be 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6 or any range therebetween.
  • F+B can be 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6 or any range therebetween.
  • the electrolyte also includes 1,3-propane sultone, vinyl sulfate, vinylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate or ⁇ - at least one of butyrolactones.
  • the electrochemical device meets at least one of the following conditions: a) based on the quality of the electrolyte, the mass percentage of the 1,3-propane sultone is 0.5% to 5%, b) based on the The quality of the electrolyte, the mass percentage of the vinyl sulfate is 0.1% to 1%, c) based on the quality of the electrolyte, the mass percentage of the vinylene carbonate is 0.1% to 1% , d) based on the quality of the electrolyte, the mass percentage of the dimethyl carbonate is 0.1% to 30%, e) based on the quality of the electrolyte, the mass percentage of the diethyl carbonate 0.1% to 30%, f) based on the quality of the electrolyte, the mass percentage of ethyl methyl carbonate is 0.1% to 30%, g) based on the quality of the electrolyte, the ⁇ -butylene
  • the mass percent content of the lactone is 0.01% to 5%. Without being
  • trinitrile compounds include 1,3,5-pentanetricarbonitrile, 1,2,3-propanetricarbonitrile, 1,3,6-hexanetricarbonitrile, 1,2,6-hexanetricarbonitrile, 1, 2,3-tris(2-cyanoethoxy)propane, 1,2,4-tris(2-cyanoethoxy)butane or 1,2,5-tris(cyanoethoxy)pentane at least one of alkanes.
  • the electrolyte solution of the present application includes lithium salt, and the present application has no special limitation on the lithium salt, as long as the purpose of the present application can be achieved.
  • lithium salts include at least one of lithium hexafluorophosphate, lithium bistrifluoromethanesulfonimide, lithium bis(fluorosulfonyl)imide, lithium tetrafluoroborate, lithium bisoxalate borate, lithium difluorooxalate borate, or lithium difluorophosphate A sort of.
  • dinitrile compounds include succinonitrile, glutaronitrile, adiponitrile, 1,5-dicyanopentane, 1,6-dicyanohexane, 1,7-dicyanoheptane, 1, 8-Dicyanoctane, 1,9-dicyanononane, 1,10-dicyanodecane, 1,12-dicyanododecane, tetramethylsuccinonitrile, 2-methyl At least one of glutaronitrile, 2,4-dimethylglutaronitrile or 2,2,4,4-tetramethylglutaronitrile.
  • the second aspect of the present application provides an electronic device comprising the electrochemical device described in the above embodiments of the present application.
  • the application provides an electrochemical device and an electronic device.
  • the electrolyte in the electrochemical device includes fluoroethylene carbonate and a trinitrile compound, wherein the mass percentage of fluoroethylene carbonate is A%, and 4 ⁇ A ⁇ 10.
  • the mass percentage of the trinitrile compound is B%, 1 ⁇ B ⁇ 3, by adjusting the mass percentage C% of the metal element M in the positive electrode active material and the mass percentage of the trinitrile compound is B% Satisfying 7 ⁇ C ⁇ B/1000 ⁇ 27, improving the floating charge performance and cycle performance of the electrochemical device.
  • a lithium-ion battery is used as an example of an electrochemical device to explain the present application, but the electrochemical device of the present application is not limited to the lithium-ion battery.
  • the present application has no special restrictions on the preparation method of the positive electrode active material containing the metal element M (hereinafter referred to as the modified positive electrode active material), and the preparation method of those skilled in the art can be adopted.
  • the modified positive electrode active material aluminum- containing compound (such as Al 2 O 3 , Al(OH) 3 , AlF 3 ), magnesium-containing compound (such as MgO) or Ti-containing compound (such as TiO 2 ) to obtain the above-mentioned modified positive electrode active material.
  • the present application can realize the change of the metal element M in the positive electrode active material layer by adjusting the content of the metal element M in the modified positive electrode active material, such as adjusting the addition amount of the metal element M-containing compound. This application does not specifically limit the adjustment process, as long as the purpose of this application can be achieved.
  • the positive electrode current collector in this application is not particularly limited, and may be any positive electrode current collector in the art, such as aluminum foil, aluminum alloy foil, or a composite current collector.
  • the negative electrode current collector in this application is not particularly limited, and materials such as metal foil or porous metal plate can be used, such as copper, nickel, titanium or iron or their alloy foil or porous plate, such as copper foil.
  • the negative active material layer includes a negative active material, a conductive agent, a binder, and a thickener.
  • the binder can be styrene-butadiene rubber (SBR), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinyl butyral (PVB), water-based acrylic resin (water-based acrylic resin) or carboxylate At least one of methyl cellulose (CMC); the thickener may be carboxymethyl cellulose (CMC).
  • the substrate of the isolation film of the present application includes, but is not limited to, selected from polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polyimide (PI) or aramid at least one of the
  • polyethylene includes at least one component selected from high-density polyethylene, low-density polyethylene, and ultra-high molecular weight polyethylene.
  • polyethylene and polypropylene are excellent in preventing short circuits and can improve the stability of electrochemical devices through the shutdown effect.
  • the substrate can be a single-layer structure or a multi-layer composite structure mixed with a thickness of 3 ⁇ m to 20 ⁇ m.
  • the electronic device of the present application is not particularly limited, and it may be used in any electronic device known in the prior art.
  • electronic devices may include, but are not limited to, notebook computers, pen-based computers, mobile computers, e-book players, cellular phones, portable fax machines, portable copiers, portable printers, headsets, VCRs, LCD TVs, portable cleaners, portable CD players, mini discs, transceivers, electronic organizers, calculators, memory cards, portable tape recorders, radios, backup power supplies, motors, cars, motorcycles, power-assisted bicycles, bicycles, Lighting appliances, toys, game consoles, clocks, electric tools, flashlights, cameras, large household storage batteries and lithium-ion capacitors, etc.
  • a lithium-ion battery can be manufactured through the following process: overlap the positive and negative electrodes through a separator, wind and fold them as needed, put them into the case, inject the electrolyte into the case and seal it.
  • anti-overcurrent elements, guide plates, etc. can also be placed in the casing according to needs, so as to prevent the internal pressure of the lithium-ion battery from rising and overcharging and discharging.
  • Scrape off the active material of the positive electrode sheet after cleaning with DMC (dimethyl carbonate), and dissolve it with a mixed solvent for example, 0.4g of positive electrode active material uses 10ml (nitric acid and hydrochloric acid are mixed according to 1:1) aqua regia and 2ml of mixed solvent of HF), set the volume to 100mL, and then use the ICP analyzer to test the content of metal elements M such as Ti, Mg, Al in the solution, and the unit is ppm.
  • the lithium-ion battery Under the condition of 45°C, the lithium-ion battery is charged to 4.5V at a constant current of 0.7C (rate), then charged at a constant voltage to a current of 0.05C, and then discharged to 3.0V at a constant current of 1C. This is a charge-discharge cycle. This is the first cycle, and the discharge capacity of the lithium-ion battery for the first cycle is recorded. The lithium ion battery is charged and discharged according to the above method, and the discharge capacity of each cycle is recorded until the discharge capacity of the lithium ion battery decays to 80% of the discharge capacity of the first cycle, and the number of charge and discharge cycles is recorded.
  • Lithium-ion battery float performance test Lithium-ion battery float performance test:
  • Lithium-ion battery thickness expansion rate (thickness of lithium-ion battery during float charge - initial thickness of lithium-ion battery) / initial thickness of lithium-ion battery ⁇ 100%.
  • LiCoO 2 lithium cobalt oxide
  • oxides containing metal element M oxides containing metal element M (a mixture of magnesium oxide (MgO), titanium dioxide (TiO 2 ), and aluminum oxide (Al 2 O 3 )), and mix them in a high-speed mixer Mix at 300r/min for 20min, place the mixture in an air kiln, heat up to 820°C at 5°C/min, keep it for 24h, take it out after natural cooling, and pass through a 300-mesh sieve to obtain a modified positive electrode active material (i.e. modified LiCoO 2 ).
  • the total content of metal elements M (Mg, Ti, Al) in the positive electrode active material is 7000 ppm, and the molar ratio of Mg element, Ti element, and Al element is 1:1:1.
  • the prepared modified LiCoO 2 , conductive agent carbon nanotube (CNT), and binder polyvinylidene fluoride were mixed according to a mass ratio of 95:2:3, and N-methylpyrrolidone (NMP) was added as a solvent. Stir under the action of a vacuum mixer until the system becomes a homogeneous positive electrode slurry with a solid content of 75 wt%.
  • NMP N-methylpyrrolidone
  • the positive electrode slurry is uniformly coated on the positive electrode current collector aluminum foil with a thickness of 12 ⁇ m, dried at 85 ° C, and cold pressed to obtain a positive electrode sheet with a positive electrode active material layer thickness of 100 ⁇ m, and then on the other side of the positive electrode sheet Repeat the above steps on one surface to obtain a positive electrode sheet coated with a positive electrode active material layer on both sides. Cut the positive pole piece into a size of 74mm ⁇ 867mm and weld the tabs for use.
  • Negative electrode active material artificial graphite, styrene-butadiene rubber (SBR) and carboxymethyl cellulose (CMC) are mixed according to mass ratio 95: 2: 3, then add deionized water as solvent, deploy the slurry that solid content is 70wt% , and stir well.
  • the slurry is evenly coated on one surface of a copper foil with a thickness of 8 ⁇ m, dried at 110° C., and cold-pressed to obtain a negative electrode sheet with a negative active material layer coated on one side with a negative active material layer thickness of 150 ⁇ m.
  • ethylene carbonate (EC), propylene carbonate (PC), and diethyl carbonate (DEC) were uniformly mixed in a weight ratio of 1:1:1 as a base solvent, Add LiPF 6 , trinitrile compound 1,3,6-hexanetrinitrile and fluoroethylene carbonate, stir evenly to form an electrolyte solution, wherein the concentration of LiPF 6 is 12.5wt%, trinitrile compound 1,3,6-
  • the mass percentages of hexanetrinitrile and fluoroethylene carbonate are shown in Table 1.
  • a polyethylene (PE) porous polymer film with a thickness of 15 ⁇ m was used as the separator.
  • the positive pole piece, the separator, and the negative pole piece are stacked in order, so that the separator is in the middle of the positive pole piece and the negative pole piece to play the role of isolation, and the electrode assembly is obtained by winding.
  • the oxide containing metal element M is a mixture of MgO and Al 2 O 3 , the molar ratio of Mg element to Al element is 1:1, the changes of related preparation parameters and properties Except as shown in Table 1, the rest are the same as in Example 10.
  • the oxide containing metal element M is Al 2 O 3 , and the changes in related preparation parameters and properties are shown in Table 1, the rest are the same as in Example 10.
  • Example 1 Except for adjusting the content of fluoroethylene carbonate in the electrolyte and the defect degree Id/Ig of the negative electrode sheet as shown in Table 2, the rest are the same as in Example 1.
  • Example 1 Except that ⁇ preparation of electrolytic solution> is different from Example 1, the rest is the same as Example 1.
  • ethylene carbonate (EC), propylene carbonate (PC), and diethyl carbonate (DEC) were uniformly mixed in a weight ratio of 10:15:54.5 as the base solvent, Add LiPF 6 , trinitrile compound 1,3,6-hexanetrinitrile and fluoroethylene carbonate, stir evenly to form an electrolyte solution, wherein the concentration of LiPF 6 is 12.5wt%, trinitrile compound 1,3,6-
  • the mass percent content of hexanetrinitrile and fluoroethylene carbonate and the changes of related preparation parameters and properties are shown in Table 3.
  • Example 1 Except that ⁇ preparation of electrolytic solution> is different from Example 1, the rest is the same as Example 1.
  • ethylene carbonate (EC), propylene carbonate (PC), and diethyl carbonate (DEC) were uniformly mixed in a weight ratio of 10:15:39.5 as a base solvent, Add LiPF 6 , trinitrile compound 1,3,6-hexanetrinitrile and fluoroethylene carbonate, stir evenly to form an electrolyte solution, wherein the concentration of LiPF 6 is 12.5wt%, trinitrile compound 1,3,6- Table 3 shows the mass percentages of hexanetrinitrile and fluoroethylene carbonate and the changes of related preparation parameters and properties.
  • Example 1 Except that ⁇ preparation of electrolytic solution> is different from Example 1, the rest is the same as Example 1.
  • ethylene carbonate (EC), propylene carbonate (PC), and diethyl carbonate (DEC) were uniformly mixed in a weight ratio of 10:15:34.5 as the base solvent, Add LiPF 6 , trinitrile compound 1,3,6-hexanetrinitrile and fluoroethylene carbonate, stir evenly to form an electrolyte solution, wherein the concentration of LiPF 6 is 12.5wt%, trinitrile compound 1,3,6-
  • the mass percent content of hexanetrinitrile and fluoroethylene carbonate and the changes of related preparation parameters and properties are shown in Table 3.
  • Example 2 Except that ⁇ preparation of electrolytic solution> is different from Example 2, the rest is the same as Example 2.
  • ethylene carbonate (EC), propylene carbonate (PC), and diethyl carbonate (DEC) were uniformly mixed in a weight ratio of 1:1:1 as a base solvent, Add LiPF 6 , trinitrile compound 1,3,6-hexanetrinitrile, fluoroethylene carbonate and dinitrile compound succinonitrile, stir well to form an electrolyte, wherein the concentration of LiPF 6 is 12.5wt%, trinitrile
  • the mass percentages of the compound 1,3,6-hexanetrinitrile, fluoroethylene carbonate, and the dinitrile compound succinonitrile, as well as the changes in related preparation parameters and properties are shown in Table 4.
  • Example 2 Except that ⁇ preparation of electrolytic solution> is different from Example 2, the rest is the same as Example 2.
  • ethylene carbonate (EC), propylene carbonate (PC), and diethyl carbonate (DEC) were uniformly mixed in a weight ratio of 1:1:1 as a base solvent, Add LiPF 6 , trinitrile compound 1,3,6-hexanetrinitrile, fluoroethylene carbonate and additive 1,3-propane sultone, and stir evenly to form an electrolyte, in which the concentration of LiPF 6 is 12.5wt %, the mass percentage content of trinitrile compound 1,3,6-hexanetrinitrile, fluoroethylene carbonate, additive 1,3-propane sultone and the changes of relevant preparation parameters and performance are shown in Table 5 .
  • Example 1 Except for adjusting the content of fluoroethylene carbonate in the electrolyte and the defect degree Id/Ig of the negative electrode sheet as shown in Table 2, the rest are the same as in Example 1.
  • Example 1 to Example 7, and Comparative Example 1 to Comparative Example 4 From Table 1, Example 1 to Example 7, and Comparative Example 1 to Comparative Example 4, it can be seen that by adjusting A, B and C ⁇ B/1000 within the scope of this application, the 45°C capacity retention and floating rate of lithium-ion batteries The charging performance is obviously improved, indicating that the lithium-ion battery of the present application has good high-temperature cycle performance and float charge performance.
  • Example 1 to Example 14 it can also be seen that on the basis of meeting A, B and C ⁇ B/1000 within the scope of the present application, by adjusting A ⁇ B, fluoroethylene carbonate and The trinitrile compound acts synergistically to obtain a lithium-ion battery with good high-temperature cycle performance and float charge performance.
  • Example 9 and Comparative Example 6 when the metal element M content is too low (such as Comparative Example 6), the 45°C capacity retention and float charge performance of lithium-ion batteries are significantly reduced; from It can be seen from Example 9 and Comparative Example 5 in Table 1 that when the content of the metal element M is too high (such as Comparative Example 5), the float charge performance of the lithium-ion battery does not improve significantly, but the capacity retention at 45°C decreases significantly. It can be seen that on the basis of satisfying A, B and C ⁇ B/1000 within the scope of this application, by adjusting the content of the metal element M within the scope of this application, a lithium-ion battery with good high-temperature cycle performance and float charge performance can be obtained.
  • Example 9 and Example 10 on the basis of satisfying A, B and C ⁇ B/1000 within the scope of the present application, by increasing the content of trinitrile compounds, the float charge of lithium-ion batteries can be further improved performance.
  • Example 2 Example 11 and Example 12 on the basis of meeting A, B and C ⁇ B/1000 within the scope of the application, as long as the trinitrile compound species is within the scope of the application, A lithium-ion battery with good high-temperature cycle performance and float charge performance can be obtained.
  • Example 10 Example 13 and Example 14 on the basis of satisfying A, B and C ⁇ B/1000 within the scope of the application, as long as the type of metal element M is within the scope of the application, A lithium-ion battery with good high-temperature cycle performance and float charge performance can be obtained.
  • Example 15 to Example 17 and Comparative Example 7 on the basis of meeting A, B and C ⁇ B/1000 in the scope of the present application, by adjusting A ⁇ (10 ⁇ Id/Ig) in this application within the scope of the application, a lithium-ion battery with good high-temperature cycle performance and float charge performance can be obtained.
  • Example 1 to Example 17 on the basis of meeting A, B and C ⁇ B/1000 within the scope of the application, by adjusting C/(3000 ⁇ Id/Ig) within the scope of the application, A lithium-ion battery with good high-temperature cycle performance and float charge performance can be obtained.
  • Example 8 Example 18 to Example 20, on the basis of meeting A, B and C ⁇ B/1000 within the scope of this application, by adjusting the content of ethylene carbonate and propylene carbonate in the electrolyte , which can further improve the high-temperature cycle performance and float charge performance of lithium-ion batteries.
  • Example 2 Example 21 to Example 26, on the basis of meeting A, B and C ⁇ B/1000 within the scope of the present application, when the electrolyte further includes dinitrile compounds, dinitrile compounds
  • dinitrile compounds when the sum of the trinitrile compound content is within the scope of the present application, the high-temperature cycle performance and float charge performance of the lithium-ion battery can be further improved.
  • Example 2 Example 28 to Example 30, it can be seen that on the basis of satisfying A, B and C ⁇ B/1000 within the scope of the present application, when the electrolyte further includes 1,3-propanesulfone At least one additive in ester, vinyl sulfate, vinylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate or ⁇ -butyrolactone can further improve the high temperature cycle performance and Float performance.

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Abstract

本申请提供了一种电化学装置及电子装置，包括正极、负极、隔离膜和电解液，电解液包括氟代碳酸乙烯酯和三腈化合物，基于电解液的质量，氟代碳酸乙烯酯的质量百分含量为A％，4≤A≤10，三腈化合物的质量百分含量为B％，1≤B≤3，正极的正极活性材料包括金属元素M，金属元素M包括Ti、Mg或Al中的至少一种，金属元素M在正极活性材料中的含量为C ppm，C和B之间满足：7≤C×B/1000≤27。本申请改善了电化学装置的浮充性能和循环性能。

Description

一种电化学装置及电子装置 技术领域
本申请涉及电化学技术领域，具体涉及一种电化学装置及电子装置。
背景技术
锂离子电池具有比能量大、工作电压高、自放电率低、体积小、重量轻等特点，广泛应用于电能储存、便携式电子设备和电动汽车等各个领域。随着锂离子电池的使用范围不断扩大，市场对锂离子电池提出了更高的要求，例如要求锂离子电池具有更快的充电速度、更长的使用寿命。
然而，随着锂离子电池充电速度的提升其温升也随之增大，高温下锂离子电池中的副反应增多，影响锂离子电池循环性能。
发明内容
本申请的目的在于提供一种电化学装置及电子装置，以提高电化学装置的循环性能。具体技术方案如下：
本申请第一方面提供了一种电化学装置，其包括正极、负极、隔离膜和电解液，其中，所述电解液包括氟代碳酸乙烯酯和三腈化合物。基于所述电解液的质量，氟代碳酸乙烯酯的质量百分含量为A％，4≤A≤10，例如，A可以为4、5、6、7、8、9、10或为其间的任意范围；三腈化合物的质量百分含量为B％，1≤B≤3，例如，B可以为1、1.5、2、2.5、3或为其间的任意范围。所述正极包括正极活性材料，所述正极活性材料包括金属元素M，金属元素M包括Ti、Mg或Al中的至少一种，金属元素M在正极活性材料中的含量为C ppm，C和B之间满足：7≤C×B/1000≤27，例如，C×B/1000可以为7、10、13、15、18、20、22、25、27或为其间的任意范围。本申请的正极可以指正极极片，负极可以指负极极片。
本申请发明人发现，通过调整A、B和C×B/1000在上述范围内，能够提升锂离子电池高温循环性能和浮充性能。不限于任何理论，这可能是由于正极活性材料中包括金属元素M时，能够提高正极的结构稳定性，但负极的结构稳定性也需提高，从而使锂离子电池的动力学性能整体提升。基于此，本申请通过调整电解液中氟代碳酸乙烯酯的含量以提高负极的成膜稳定性，通过调整电解液中三腈化合物的含量以提高锂离子电池的高温循环性能，从而使锂离子电池具有良好的高温循环性能和浮充性能。
本申请的一种实施方案中，A和B之间满足：6≤A×B≤22，例如，A×B可以为6、 8、10、12、15、17、20、22或为其间的任意范围。通过调整A×B在上述范围内，能够使电解液中氟代碳酸乙烯酯和三腈化合物协同作用，使锂离子电池具有良好的高温循环性能和浮充性能。
本申请的一种实施方案中，负极的缺陷程度为Id/Ig，满足：0.13＜Id/Ig≤0.3。Id/Ig与A之间满足：6≤A×(10×Id/Ig)≤24。例如，Id/Ig可以为0.13、0.15、0.2、0.25、0.3或为其间的任意范围，A×(10×Id/Ig)可以为6、8、9、10、12、15、17、29、20、22、24或为其间的任意范围。不限于任何理论，A×(10×Id/Ig)过小时(例如小于6)，负极侧动力学性能不足，副反应增加，锂离子电池循环稳定性变差；A×(10×Id/Ig)过大时(例如大于24)，锂离子电池高温稳定性受到影响。通过调整A×(10×Id/Ig)在上述范围内，能够得到具有良好高温循环性能和浮充性能的锂离子电池。
本申请中，负极的缺陷程度Id/Ig中，Id是指负极活性材料拉曼光谱中的D峰峰强，Ig是指负极活性材料拉曼光谱中的G峰峰强，Id/Ig表示负极活性材料的缺陷密集程度，Id/Ig比值越大，缺陷程度越大。
本申请的一种实施方案中，金属元素M在正极活性材料中的含量C满足：5000ppm≤C≤9000ppm。例如，C可以为5000ppm、5500ppm、6000ppm、6500ppm、7000ppm、7500ppm、8000ppm、8500ppm、9000ppm或为其间的任意范围。不限于任何理论，通过调整C在上述范围内，能够得到具有良好高温循环性能和能量密度的锂离子电池。
本申请的一种实施方案中，C与Id/Ig之间满足：6≤C/(3000×Id/Ig)≤20。例如，C/(3000×Id/Ig)可以为6、7、10、12、15、18、20或为其间的任意范围。不限于任何理论，通过调整C/(3000×Id/Ig)在上述范围内，能够得到具有良好高温循环性能和浮充性能的锂离子电池。
本申请的一种实施方案中，所述电解液还包括碳酸乙烯酯和碳酸丙烯酯，基于所述电解液的质量，碳酸乙烯酯的质量百分含量为D％，碳酸丙烯酯的质量百分含量为E％，D和E之间满足：20≤D+E≤50，且1≤E/D≤3。例如，D+E可以为20、25、30、35、40、45、50或为其间的任意范围，E/D可以为1、1.5、2、2.5、3或为其间的任意范围。不限于任何理论，通过协同调整D+E和E/D在上述范围内，能够进一步提高锂离子电池的高温循环性能和浮充性能。
本申请的一种实施方案中，所述电解液还包括二腈化合物，基于所述电解液的质量，二腈化合物的质量百分含量为F％，1≤F≤3。例如，F可以为1、1.5、2、2.5、3或为其 间的任意范围。不限于任何理论，当二腈化合物含量过低时(例如低于1％)，对正极的保护效果不明显；当二腈化合物含量过高时(例如高于3％)，会影响电解液的粘度从而增大锂离子电池的内阻。通过调整二腈化合物含量在上述范围内，能够进一步提高锂离子电池的高温循环性能和浮充性能。
本申请的一种实施方案中，F与B之间满足：2≤F+B≤6。例如，F+B可以为2、2.5、3、3.5、4、4.5、5、5.5、6或为其间的任意范围。不限于任何理论，通过调整F+B在上述范围内，能够进一步提高锂离子电池的高温循环性能和浮充性能。
本申请的一种实施方案中，所述电解液还包括1,3-丙烷磺内酯、硫酸乙烯酯、碳酸亚乙烯酯、碳酸二甲酯、碳酸二乙酯、碳酸甲乙酯或γ-丁内酯中的至少一种。所述电化学装置满足以下条件中的至少一者：a)基于所述电解液的质量，所述1,3-丙烷磺内酯的质量百分含量为0.5％至5％，b)基于所述电解液的质量，所述硫酸乙烯酯的质量百分含量为0.1％至1％，c)基于所述电解液的质量，所述碳酸亚乙烯酯的质量百分含量为0.1％至1％，d)基于所述电解液的质量，所述碳酸二甲酯的质量百分含量为0.1％至30％，e)基于所述电解液的质量，所述碳酸二乙酯的质量百分含量为0.1％至30％，f)基于所述电解液的质量，所述碳酸甲乙酯的质量百分含量为0.1％至30％，g)基于所述电解液的质量，所述γ-丁内酯的质量百分含量为0.01％至5％。不限于任何理论，通过调整上述电解液添加剂在本申请范围内，能够进一步提高锂离子电池的高温循环性能和浮充性能。
本申请对三腈化合物没有特别限制，只要能实现本申请目的即可。例如，三腈化合物包括1,3,5-戊三甲腈、1,2,3-丙三甲腈、1,3,6-己烷三腈、1,2,6-己烷三腈、1,2,3-三(2-氰基乙氧基)丙烷、1,2,4-三(2-氰基乙氧基)丁烷或1,2,5-三(氰基乙氧基)戊烷中的至少一种。
本申请的电解液中包括锂盐，本申请对锂盐没有特别限制，只要能实现本申请目的即可。例如，锂盐包括六氟磷酸锂、双三氟甲烷磺酰亚胺锂、双(氟磺酰)亚胺锂、四氟硼酸锂、双草酸硼酸锂、二氟草酸硼酸锂或二氟磷酸锂中的至少一种。
本申请对二腈化合物没有特别限制，只要能实现本申请目的即可。例如，二腈化合物包括丁二腈、戊二腈、己二腈、1,5-二氰基戊烷、1,6-二氰基己烷、1,7-二氰基庚烷、1,8-二氰基辛烷、1,9-二氰基壬烷、1,10-二氰基癸烷、1,12-二氰基十二烷、四甲基丁二腈、2-甲基戊二腈、2,4-二甲基戊二腈或2,2,4,4-四甲基戊二腈中的至少一种。
本申请的第二方面提供了一种电子装置，包含本申请上述实施方案中所述的电化学装置。
本申请提供了一种电化学装置及电子装置，电化学装置中的电解液包括氟代碳酸乙烯酯和三腈化合物，其中氟代碳酸乙烯酯的质量百分含量为A％，4≤A≤10，三腈化合物的质量百分含量为B％，1≤B≤3，通过调整属金属元素M在正极活性材料中的质量百分含量C％与三腈化合物的质量百分含量为B％满足7≤C×B/1000≤27，改善了电化学装置的浮充性能和循环性能。
具体实施方式
为使本申请的目的、技术方案、及优点更加清楚明白，以下参照实施例，对本申请进一步详细说明。显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域普通技术人员所获得的所有其他技术方案，都属于本申请保护的范围。
需要说明的是，本申请的具体实施方式中，以锂离子电池作为电化学装置的例子来解释本申请，但是本申请的电化学装置并不仅限于锂离子电池。
本申请对含有金属元素M的正极活性材料(下文简称改性正极活性材料)的制备方法没有特别限制，可以采用本领域技术人员的制备方法，例如，可以在正极活性材料LiCoO 2中加入含铝化合物(例如Al 2O 3、Al(OH) 3、AlF 3)、含镁化合物(例如MgO)或含Ti化合物(例如TiO 2)得到上述改性正极活性材料。另外，本申请可以通过调整改性正极活性材料中金属元素M的含量，例如调整含金属元素M化合物的加入量，即可实现正极活性材料层中金属元素M的变化。本申请对其调整过程不做具体限定，只要能实现本申请目的即可。
本申请中的正极集流体没有特别限制，可以为本领域的任何正极集流体，例如铝箔、铝合金箔或复合集流体等。
本申请中的负极集流体没有特别限制，可以使用金属箔材或多孔金属板等材料，例如铜、镍、钛或铁等金属或它们的合金的箔材或多孔板，如铜箔。负极活性材料层包括负极活性材料、导电剂、粘结剂和增稠剂。粘结剂可以是丁苯橡胶(SBR)、聚偏二氟乙烯(PVDF)、聚四氟乙烯(PTFE)、聚乙烯醇缩丁醛(PVB)、水性丙烯酸树脂(water-basedacrylic resin)或羧甲基纤维素(CMC)中的至少一种；增稠剂可以是羧甲基纤维素(CMC)。
本申请的隔离膜的基材包括但不限于，选自聚乙烯(PE)、聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚酰亚胺(PI)或芳纶中的至少一种。举例来说，聚乙烯包括选自高密度聚乙烯、低密度聚乙烯和超高分子量聚乙烯中的至少一种组分。尤其是聚乙烯和聚丙 烯，它们对防止短路具有优良的作用，并可以通过关断效应改善电化学装置的稳定性。基材可以是单层结构或多种混合的多层复合结构，厚度为3μm至20μm。
本申请的电子装置没有特别限定，其可以是用于现有技术中已知的任何电子装置。在一些实施例中，电子装置可以包括，但不限于，笔记本电脑、笔输入型计算机、移动电脑、电子书播放器、便携式电话、便携式传真机、便携式复印机、便携式打印机、头戴式立体声耳机、录像机、液晶电视、手提式清洁器、便携CD机、迷你光盘、收发机、电子记事本、计算器、存储卡、便携式录音机、收音机、备用电源、电机、汽车、摩托车、助力自行车、自行车、照明器具、玩具、游戏机、钟表、电动工具、闪光灯、照相机、家庭用大型蓄电池和锂离子电容器等。
电化学装置的制备过程为本领域技术人员所熟知的，本申请没有特别的限制。例如锂离子电池可以通过以下过程制造：将正极和负极经由隔离膜重叠，并根据需要将其卷绕、折叠等操作后放入壳体内，将电解液注入壳体并封口。此外，也可以根据需要将防过电流元件、导板等置于壳体中，从而防止锂离子电池内部的压力上升、过充放电。
以下，举出实施例及对比例来对本申请的实施方式进行更具体地说明。各种的试验及评价按照下述的方法进行。另外，只要无特别说明，“份”、“％”为质量基准。
测试方法和设备：
正极活性材料金属元素M含量测试：
将用DMC(碳酸二甲酯)清洗后的正极极片的活性材料用刮刀刮下，用混合溶剂溶解(例如，0.4g正极活性材料使用10ml(硝酸与盐酸按照1∶1混合)王水与2ml HF的混合溶剂)，定容至100mL，然后使用ICP分析仪测试溶液中Ti、Mg、Al等金属元素M的含量，单位为ppm。
负极的缺陷程度测试：
将烘干的负极极片保持表面平整，放置在拉曼测试仪器(JobinYvonLabRAM HR)的样品台中进行测试，得到拉曼光谱图。在拉曼光谱图中确定D峰峰强和G峰峰强，计算Id/Ig，即为负极的缺陷程度。
锂离子电池循环性能测试：
在45℃条件下，将锂离子电池以0.7C(倍率)恒流充电至4.5V，然后恒压充电至电流为0.05C，再用1C恒流放电至3.0V，此为一个充放电循环，此时为首次循环，记录锂 离子电池第一次循环的放电容量。将锂离子电池按照上述方法进行充放电循环，记录每一次循环的放电容量，直至锂离子电池的放电容量衰减至第一次循环的放电容量的80％，记录充放电循环次数。
锂离子电池浮充性能测试：
在45℃下，将锂离子电池以0.7C恒流充电至4.5V，然后恒压充电90天，用千分尺测试并记录锂离子电池的厚度，期间每隔3天测试并记录一次锂离子电池厚度。根据如下表达式计算锂离子电池的浮充厚度膨胀率，并以厚度膨胀率达到10％时的时间作为评价锂离子电池浮充性能优劣的指标，厚度膨胀率达到10％时的时间越长，表明锂离子电池的浮充性能越好。
锂离子电池厚度膨胀率＝(锂离子电池浮充过程中的厚度-锂离子电池初始厚度)/锂离子电池初始厚度×100％。
实施例1
<改性正极活性材料的制备>
将市售钴酸锂(LiCoO 2)、含有金属元素M的氧化物(氧化镁(MgO)、二氧化钛(TiO 2)、三氧化二铝(Al 2O 3)的混合物)混合，在高速混合机中300r/min混合20min，将混合物置于空气窑炉中，以5℃/min升温至820℃，保持24h，自然冷却后取出，过300目筛后得到改性正极活性材料(即改性LiCoO 2)。该改性正极活性材料中，金属元素M(Mg、Ti、Al)在正极活性材料中的总含量为7000ppm，Mg元素、Ti元素、Al元素的摩尔比为1∶1∶1。
<正极极片的制备>
将制得的改性LiCoO 2、导电剂碳纳米管(CNT)、粘结剂聚偏二氟乙烯按照质量比95∶2∶3进行混合，加入N-甲基吡咯烷酮(NMP)作为溶剂，在真空搅拌机作用下搅拌至体系成均一状、固含量为75wt％的正极浆料。将正极浆料均匀涂覆于厚度为12μm的正极集流体铝箔上，在85℃条件下烘干，冷压后得到正极活性材料层厚度为100μm的正极极片，然后在该正极极片的另一个表面上重复以上步骤，得到双面涂布有正极活性材料层的正极极片。将正极极片裁切成74mm×867mm的规格并焊接极耳后待用。
<负极极片的制备>
将负极活性材料人造石墨、丁苯橡胶(SBR)及羧甲基纤维素(CMC)按质量比95∶ 2∶3混合，然后加入去离子水作为溶剂，调配成固含量为70wt％的浆料，并搅拌均匀。将浆料均匀涂布在厚度为8μm的铜箔的一个表面上，110℃条件下烘干，冷压后得到负极活性材料层厚度为150μm的单面涂布负极活性材料层的负极极片，然后在该负极极片的另一个表面上重复以上涂布步骤，得到双面涂布有负极活性材料层的负极极片。将负极极片裁切成(74mm×867mm)的规格并焊接极耳后待用。其中，负极极片的缺陷程度Id/Ig为0.17。
<电解液的制备>
在含水量小于10ppm的氩气气氛手套箱中，将碳酸乙烯酯(EC)、碳酸丙烯酯(PC)、碳酸二乙酯(DEC)按重量比1∶1∶1均匀混合，作为基础溶剂，加入LiPF 6、三腈化合物1,3,6-己烷三腈和氟代碳酸乙烯酯，搅拌均匀，形成电解液，其中LiPF 6的浓度为12.5wt％，三腈化合物1,3,6-己烷三腈和氟代碳酸乙烯酯的质量百分含量如表1所示。
<隔离膜的制备>
以厚度为15μm的聚乙烯(PE)多孔聚合薄膜作为隔离膜。
<锂离子电池的制备>
将正极极片、隔离膜、负极极片按顺序叠好，使隔离膜处于正极极片和负极极片中间起到隔离的作用，并卷绕得到电极组件。将电极组件装入铝塑膜包装袋中，并在80℃下脱去水分，注入配好的电解液，经过真空封装、静置、化成、整形等工序得到锂离子电池。
实施例2至实施例12
除了调整电解液中氟代碳酸乙烯酯含量、三腈化合物种类和含量、金属元素M总含量，相关制备参数及性能的变化如表1所示以外，其余与实施例1相同。
实施例13
除了在<改性正极活性材料的制备>中，含有金属元素M的氧化物为MgO和Al 2O 3的混合物，Mg元素、Al元素的摩尔比为1∶1，相关制备参数及性能的变化如表1所示以外，其余与实施例10相同。
实施例14
除了在<改性正极活性材料的制备>中，含有金属元素M的氧化物为Al 2O 3，相关制备参数及性能的变化如表1所示以外，其余与实施例10相同。
实施例15至实施例17
除了如表2所示调整电解液中氟代碳酸乙烯酯含量以及负极极片的缺陷程度Id/Ig以外，其余与实施例1相同。
实施例18
除了<电解液的制备>与实施例1不同以外，其余与实施例1相同。
在含水量小于10ppm的氩气气氛手套箱中，将碳酸乙烯酯(EC)、碳酸丙烯酯(PC)、碳酸二乙酯(DEC)按重量比10∶15∶54.5均匀混合，作为基础溶剂，加入LiPF 6、三腈化合物1,3,6-己烷三腈和氟代碳酸乙烯酯，搅拌均匀，形成电解液，其中LiPF 6的浓度为12.5wt％，三腈化合物1,3,6-己烷三腈、氟代碳酸乙烯酯的质量百分含量及相关制备参数及性能的变化如表3所示。
实施例19
除了<电解液的制备>与实施例1不同以外，其余与实施例1相同。
在含水量小于10ppm的氩气气氛手套箱中，将碳酸乙烯酯(EC)、碳酸丙烯酯(PC)、碳酸二乙酯(DEC)按重量比10∶15∶39.5均匀混合，作为基础溶剂，加入LiPF 6、三腈化合物1,3,6-己烷三腈和氟代碳酸乙烯酯，搅拌均匀，形成电解液，其中LiPF 6的浓度为12.5wt％，三腈化合物1,3,6-己烷三腈、氟代碳酸乙烯酯的质量百分含量及相关制备参数及性能的变化如表3所示。
实施例20
除了<电解液的制备>与实施例1不同以外，其余与实施例1相同。
在含水量小于10ppm的氩气气氛手套箱中，将碳酸乙烯酯(EC)、碳酸丙烯酯(PC)、碳酸二乙酯(DEC)按重量比10∶15∶34.5均匀混合，作为基础溶剂，加入LiPF 6、三腈化合物1,3,6-己烷三腈和氟代碳酸乙烯酯，搅拌均匀，形成电解液，其中LiPF 6的浓度为12.5wt％，三腈化合物1,3,6-己烷三腈、氟代碳酸乙烯酯的质量百分含量及相关制备参数及性能的变化如表3所示。
实施例21
除了<电解液的制备>与实施例2不同以外，其余与实施例2相同。
<电解液的制备>
在含水量小于10ppm的氩气气氛手套箱中，将碳酸乙烯酯(EC)、碳酸丙烯酯(PC)、碳酸二乙酯(DEC)按重量比1∶1∶1均匀混合，作为基础溶剂，加入LiPF 6、三腈化合物1,3,6-己烷三腈、氟代碳酸乙烯酯和二腈化合物丁二腈，搅拌均匀，形成电解液，其中LiPF 6的浓度为12.5wt％，三腈化合物1,3,6-己烷三腈、氟代碳酸乙烯酯、二腈化合物丁二腈的质量百分含量及相关制备参数及性能的变化如表4所示。
实施例22至实施例27
除了在<电解液的制备>中，如表4所示调整二腈化合物的种类和含量以外，其余与实施例21相同。
实施例28
除了<电解液的制备>与实施例2不同以外，其余与实施例2相同。
<电解液的制备>
在含水量小于10ppm的氩气气氛手套箱中，将碳酸乙烯酯(EC)、碳酸丙烯酯(PC)、碳酸二乙酯(DEC)按重量比1∶1∶1均匀混合，作为基础溶剂，加入LiPF 6、三腈化合物1,3,6-己烷三腈、氟代碳酸乙烯酯和添加剂1,3-丙磺酸内酯，搅拌均匀，形成电解液，其中LiPF 6的浓度为12.5wt％，三腈化合物1,3,6-己烷三腈、氟代碳酸乙烯酯、添加剂1,3-丙磺酸内酯的质量百分含量及相关制备参数及性能的变化如表5所示。
实施例29至实施例30
除了在<电解液的制备>中，如表5所示调整添加剂的种类和含量以外，其余与实施例28相同。
对比例1至对比例6
除了调整电解液中三腈化合物种类、氟代碳酸乙烯酯含量以及三腈化合物含量、金属元素M总含量，相关制备参数及性能的变化如表1所示以外，其余与实施例1相同。
对比例7
除了如表2所示调整电解液中氟代碳酸乙烯酯含量以及负极极片的缺陷程度Id/Ig以外，其余与实施例1相同。
表1
Figure PCTCN2021135355-appb-000001
Figure PCTCN2021135355-appb-000002
表2
Figure PCTCN2021135355-appb-000003
表3
Figure PCTCN2021135355-appb-000004
表4
Figure PCTCN2021135355-appb-000005
Figure PCTCN2021135355-appb-000006
表4中，“/”表示不含有或未测得。
表5
Figure PCTCN2021135355-appb-000007
表5中，“/”表示不含有或未测得。
从表1实施例1至实施例7、对比例1至对比例4可以看出，通过调整A、B和C×B/1000在本申请范围内，锂离子电池的45℃容量保持率和浮充性能明显提升，表明本申请的锂离子电池具有良好的高温循环性能和浮充性能。
从表1实施例1至实施例14还可以看出，在满足A、B和C×B/1000在本申请范围的基础上，通过调整A×B，使电解液中氟代碳酸乙烯酯和三腈化合物协同作用，能够得到具有良好高温循环性能和浮充性能的锂离子电池。
从表1实施例8、实施例9和对比例6可以看出，当金属元素M含量过低时(例如对比例6)，锂离子电池的45℃容量保持率和浮充性能明显下降；从表1实施例9和对比例5可以看出，当金属元素M含量过高时(例如对比例5)，锂离子电池的浮充性能提升幅度不明显，但45℃容量保持率反而显著下降。可见，在满足A、B和C×B/1000在本申请范围的基础上，通过调整金属元素M的含量在本申请范围内，能够得到具有良好高温循环性能和浮充性能的锂离子电池。
从表1实施例9和实施例10可以看出，在满足A、B和C×B/1000在本申请范围的基 础上，通过增加三腈化合物的含量，能够进一步提高锂离子电池的浮充性能。
从表1实施例2、实施例11和实施例12可以看出，在满足A、B和C×B/1000在本申请范围的基础上，只要使得三腈化合物种类在本申请范围内，就能够得到具有良好高温循环性能和浮充性能的锂离子电池。
从表1实施例10、实施例13和实施例14可以看出，在满足A、B和C×B/1000在本申请范围的基础上，只要使得金属元素M的种类在本申请范围内，就能够得到具有良好高温循环性能和浮充性能的锂离子电池。
从表2实施例15至实施例17和对比例7可以看出，在满足A、B和C×B/1000在本申请范围的基础上，通过调整A×(10×Id/Ig)在本申请范围内，能够得到具有良好高温循环性能和浮充性能的锂离子电池。
从表3实施例1至实施例17可以看出，在满足A、B和C×B/1000在本申请范围的基础上，通过调整C/(3000×Id/Ig)在本申请范围内，能够得到具有良好高温循环性能和浮充性能的锂离子电池。
从表3实施例8、实施例18至实施例20可以看出，在满足A、B和C×B/1000在本申请范围的基础上，通过调整电解液中碳酸乙烯酯和碳酸丙烯酯含量，能够进一步提升锂离子电池的高温循环性能和浮充性能。
从表4实施例2、实施例21至实施例26可以看出，在满足A、B和C×B/1000在本申请范围的基础上，当电解液中进一步包括二腈化合物，二腈化合物和三腈化合物含量之和在本申请范围内时，能够进一步提升锂离子电池的高温循环性能和浮充性能。
从表5实施例2、实施例28至实施例30可以看出，在满足A、B和C×B/1000在本申请范围的基础上，当电解液中进一步包括1,3-丙烷磺内酯、硫酸乙烯酯、碳酸亚乙烯酯、碳酸二甲酯、碳酸二乙酯、碳酸甲乙酯或γ-丁内酯中的至少一种添加剂时，能够进一步提升锂离子电池的高温循环性能和浮充性能。
以上所述仅为本申请的较佳实施例，并不用以限制本申请，凡在本申请的精神和原则之内，所做的任何修改、等同替换、改进等，均应包含在本申请保护的范围之内。

Claims (14)

  1. 一种电化学装置，其包括正极、负极、隔离膜和电解液，其中，
    所述电解液包括氟代碳酸乙烯酯和三腈化合物，基于所述电解液的质量，氟代碳酸乙烯酯的质量百分含量为A％，4≤A≤10，三腈化合物的质量百分含量为B％，1≤B≤3；
    所述正极包括正极活性材料，所述正极活性材料包括金属元素M，金属元素M包括Ti、Mg或Al中的至少一种，金属元素M在正极活性材料中的含量为C ppm，C和B之间满足：7≤C×B/1000≤27。
  2. 根据权利要求1所述的电化学装置，其中，A和B之间满足：6≤A×B≤22。
  3. 根据权利要求1所述的电化学装置，其中，所述负极的缺陷程度为Id/Ig，满足：0.13＜Id/Ig≤0.3，6≤A×(10×Id/Ig)≤24。
  4. 根据权利要求3所述的电化学装置，其中，金属元素M在正极活性材料中的含量C满足：5000ppm≤C≤9000ppm。
  5. 根据权利要求4所述的电化学装置，其中，C与Id/Ig之间满足：6≤C/(3000×Id/Ig)≤20。
  6. 根据权利要求1所述的电化学装置，其中，所述电解液还包括碳酸乙烯酯和碳酸丙烯酯，基于所述电解液的质量，碳酸乙烯酯的质量百分含量为D％，碳酸丙烯酯的质量百分含量为E％，D和E之间满足：20≤D+E≤50，且1≤E/D≤3。
  7. 根据权利要求1所述的电化学装置，其中，所述电解液还包括二腈化合物，基于所述电解液的质量，二腈化合物的质量百分含量为F％，1≤F≤3。
  8. 根据权利要求7所述的电化学装置，其中，F与B之间满足：2≤F+B≤6。
  9. 根据权利要求1所述的电化学装置，其中，所述电解液还包括1,3-丙烷磺内酯、硫酸乙烯酯、碳酸亚乙烯酯、碳酸二甲酯、碳酸二乙酯、碳酸甲乙酯或γ-丁内酯中的至少一种。
  10. 根据权利要求9所述的电化学装置，其中，所述电化学装置满足以下条件中的至少一者：
    a)基于所述电解液的质量，所述1,3-丙烷磺内酯的质量百分含量为0.5％至5％；
    b)基于所述电解液的质量，所述硫酸乙烯酯的质量百分含量为0.1％至1％；
    c)基于所述电解液的质量，所述碳酸亚乙烯酯的质量百分含量为0.1％至1％；
    d)基于所述电解液的质量，所述碳酸二甲酯的质量百分含量为0.1％至30％；
    e)基于所述电解液的质量，所述碳酸二乙酯的质量百分含量为0.1％至30％；
    f)基于所述电解液的质量，所述碳酸甲乙酯的质量百分含量为0.1％至30％；
    g)基于所述电解液的质量，所述γ-丁内酯的质量百分含量为0.01％至5％。
  11. 根据权利要求1所述的电化学装置，其中，所述三腈化合物包括1,3,5-戊三甲腈、1,2,3-丙三甲腈、1,3,6-己烷三腈、1,2,6-己烷三腈、1,2,3-三(2-氰基乙氧基)丙烷、1,2,4-三(2-氰基乙氧基)丁烷或1,2,5-三(氰基乙氧基)戊烷中的至少一种。
  12. 根据权利要求1所述的电化学装置，其中，所述电解液中包括锂盐，所述锂盐包括六氟磷酸锂、双三氟甲烷磺酰亚胺锂、双(氟磺酰)亚胺锂、四氟硼酸锂、双草酸硼酸锂、二氟草酸硼酸锂或二氟磷酸锂中的至少一种。
  13. 根据权利要求7所述的电化学装置，其中，所述二腈化合物包括丁二腈、戊二腈、己二腈、1,5-二氰基戊烷、1,6-二氰基己烷、1,7-二氰基庚烷、1,8-二氰基辛烷、1,9-二氰基壬烷、1,10-二氰基癸烷、1,12-二氰基十二烷、四甲基丁二腈、2-甲基戊二腈、2,4-二甲基戊二腈或2,2,4,4-四甲基戊二腈中的至少一种。
  14. 一种电子装置，包含权利要求1-13中任一项所述的电化学装置。
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