WO2022205661A1 - 电化学装置和电子装置 - Google Patents

电化学装置和电子装置 Download PDF

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WO2022205661A1
WO2022205661A1 PCT/CN2021/104955 CN2021104955W WO2022205661A1 WO 2022205661 A1 WO2022205661 A1 WO 2022205661A1 CN 2021104955 W CN2021104955 W CN 2021104955W WO 2022205661 A1 WO2022205661 A1 WO 2022205661A1
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positive electrode
current collector
electrolyte
electrode current
compound
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PCT/CN2021/104955
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English (en)
French (fr)
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张丽兰
张水蓉
唐超
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宁德新能源科技有限公司
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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
    • H01M10/052—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
    • 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
    • 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
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic electrolyte
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application relates to the field of electrochemical technology, and in particular, to an electrochemical device and an electronic device.
  • Electrochemical devices eg, lithium-ion batteries
  • electrochemical devices are widely used in electronic devices in various fields. With the development of electronic devices, people have put forward higher requirements for the energy density of electrochemical devices.
  • the present application provides an electrochemical device and an electronic device, which can improve the cycle performance and overdischarge storage performance of the electrochemical device, reduce the corrosion of the positive electrode current collector by the electrolyte, and ensure the safety performance of the electrochemical device.
  • an electrochemical device comprising: a positive electrode, a negative electrode, a separator, and an electrolyte; and the electrolyte, including the compound shown in formula I:
  • the compound represented by formula I accounts for A% of the total mass of the electrolyte, and A is 0.3 to 40;
  • R 1 and R 2 are each independently selected from hydrogen, halogen, alkyl with 1 to 5 carbon atoms, substituted by halogen Alkyl with 1 to 5 carbon atoms, alkenyl with 1 to 5 carbon atoms or alkenyl with 1 to 5 carbon atoms substituted by halogen, alkynyl with 1 to 5 carbon atoms or alkenyl with 1 to 5 carbon atoms A halogen-substituted alkynyl group having 1 to 5 carbon atoms; and at least one of R 1 and R 2 contains a halogen;
  • the positive electrode includes a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector, and the positive electrode collector The tensile strength of the fluid is B MPa, and 2 ⁇ B/A ⁇ 750.
  • the compound represented by formula I includes: at least one of fluoroethylene carbonate, difluoroethylene carbonate, methyl fluoroethylene carbonate or 4-fluoro-5-methyl ethylene carbonate kind.
  • the electrolyte also includes: a dinitrile compound
  • the electrolyte also includes: a polynitrile compound with a cyano group number greater than or equal to 3;
  • the electrolyte also includes: an oxygen-containing heterocyclic compound.
  • the dinitrile compound accounts for C% of the total mass of the electrolyte
  • the polynitrile compound accounts for D% of the total mass of the electrolyte, 0.5 ⁇ D/C ⁇ 20;
  • the dinitrile compound accounts for C% of the total mass of the electrolyte, and satisfies 0.5 ⁇ C ⁇ 7.
  • the polynitrile compound accounts for D% of the total mass of the electrolyte, and satisfies 0.1 ⁇ D ⁇ 4.
  • the compound of formula I and the polynitrile compound satisfy: 0.02 ⁇ A/D ⁇ 130.
  • the dinitrile compounds include: succinonitrile, glutaronitrile, adiponitrile, pimeliconitrile, suberonitrile, azelonitrile, sebaconitrile, ethylene glycol (bispropionitrile) ether ( at least one of nitrile ether) or fumarate;
  • the polynitrile compounds include: 1,3,6-hexanetrinitrile, 1,2,6-hexanetrinitrile, 1,3,5-pentanetrinitrile, nonanetrinitrile, 1 ,3,5-benzenetricarbonitrile, 2,4,6-trifluorobenzene-1,3,5-tricarbonitrile, 1,3,5-cyclohexanetricarbonitrile, 1,2,3-propanetricarbonitrile, 1 , at least one of 3,5-benzenetricyano or 1,2,3-tris(2-cyanooxy)propane.
  • the oxygen-containing heterocyclic compounds include: 1,3-dioxane, dioxolane, 4-methyl-1,3-dioxane, tetrahydropyran, tetrahydrofuran or at least one of 1,2-epoxybutane.
  • the oxygen-containing heterocyclic compound accounts for 0.01% to 3% of the total mass of the electrolyte.
  • the tensile strength of the positive electrode current collector is B MPa, which satisfies B>100.
  • the positive electrode current collector satisfies at least one of the conditions (e) to (j):
  • the positive electrode current collector comprises aluminum
  • the thickness of the positive electrode current collector is 5 ⁇ m to 20 ⁇ m;
  • the positive electrode current collector contains M element, the M element includes at least one of silicon, copper, manganese, iron, zinc, magnesium, titanium, and vanadium, and the percentage of M element in the total weight of the positive electrode current collector is not more than 2%;
  • the weight per unit area of the positive electrode current collector is 15g/m 2 to 100g/m 2 ;
  • the positive electrode current collector has a soldering area, and the area of the soldering area is F cm 2 , 1 ⁇ F ⁇ 50.
  • the anode includes an anode current collector and an anode active material layer
  • the anode active material layer includes an anode material
  • the anode material includes a silicon-based material
  • at least a part of the particle surface of the silicon-based material has a protective layer.
  • the protective layer includes: carbon material or Me x O y , wherein Me includes at least one of Al, Si, Mn, V, Cr, Co or Zr, x is 1 to 2, and y is 1 to 3.
  • an electronic device including the electrochemical device according to any one of the above.
  • the electrochemical device provided by the embodiments of the present application includes the compound represented by formula I, and the compound represented by formula I can continuously repair the negative electrode SEI (solid electrolyte interphase, solid electrolyte boundary phase) film during the over-discharge storage process of the electrochemical device, effectively improving the negative electrode interface, reducing over-discharge storage flatulence and improving cycle performance, and by controlling the ratio of the tensile strength of the positive electrode current collector to the content of the compound represented by formula I within a certain range.
  • the present application can ensure the cycle performance and overdischarge storage performance of the electrochemical device, and can improve the safety performance of the electrochemical device.
  • FIG. 1 is a schematic diagram of a connection between a positive electrode and a tab according to an embodiment of the present disclosure.
  • fluorine-containing additives such as FEC
  • FEC fluorine-containing additives
  • the electrolyte to improve the cycle performance of the electrochemical device of the negative electrode system.
  • FEC can react with lithium hexafluorophosphate to generate corrosive components that corrode the positive current collector, such as aluminum foil, resulting in electrochemical devices.
  • the safety performance such as drop performance and impact performance is reduced.
  • an electrochemical device comprising: a positive electrode, a negative electrode, a separator, and an electrolyte; the electrolyte, including the compound shown in formula I:
  • the compound represented by formula I accounts for A% of the total mass of the electrolyte, and A is 0.3 to 40;
  • R 1 and R 2 are independently selected from hydrogen radicals, halogens, alkyl groups with 1 to 5 carbon atoms, halogenated substituted alkyl having 1 to 5 carbon atoms, alkenyl having 1 to 5 carbon atoms or alkenyl having 1 to 5 carbon atoms substituted by halogen, alkynyl having 1 to 5 carbon atoms or The alkynyl group having a carbon number of 1 to 5 substituted by halogen; and at least one of R 1 and R 2 contains a halogen;
  • the positive electrode comprises a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector, the positive electrode The tensile strength of the current collector is B MPa, and 2 ⁇ B/A ⁇ 750.
  • the negative electrode includes a negative electrode current collector and a negative electrode active material layer disposed on at least one
  • the SEI film of the negative electrode can be continuously repaired during the over-discharge storage process of the electrochemical device, effectively improving the negative electrode interface and reducing over-discharge. Store flatulence and improve cycle performance.
  • the tensile strength of the positive electrode current collector and the content of the compound shown in formula I are controlled in the present application. ratio, the cathode current collector can maintain a certain tensile strength and improve the drop performance and impact performance of the electrochemical device after cycling.
  • the electrochemical device proposed in the present application can ensure the cycle performance and over-discharge storage performance of the electrochemical device, and at the same time reduce the corrosion of the electrolyte to the positive electrode current collector, so that the positive electrode current collector can maintain a certain stretch under high temperature for a long time. strength and improve the safety performance of electrochemical devices.
  • the compound represented by formula I includes: at least one of fluoroethylene carbonate, difluoroethylene carbonate, methyl fluoroethylene carbonate or 4-fluoro-5-methyl ethylene carbonate kind. In some embodiments of the present application, the content of the compound represented by formula I is 0.1% to 40%. In some embodiments of the present application, the content of the compound represented by formula I is 1% to 20%. In some embodiments of the present application, the content of the compound represented by formula I is 4% to 20%.
  • the above compounds can preferentially form a stable SEI film with the negative electrode active material layer, thereby protecting the negative electrode active material layer.
  • the electrolyte further includes: a dinitrile compound.
  • the electrolyte further includes: a polynitrile compound with a number of cyano groups greater than or equal to 3.
  • the cyano group has a high bond energy and is not easily oxidized
  • the nitrile compound has good stability on the positive electrode, and has strong oxidation resistance
  • the cyano group has a strong coordination ability, which can be Combined with the active sites on the surface of the positive active material layer, the decomposition effect of the positive active material layer on the electrolyte is reduced, and the resistance of the electrolyte to the oxidation of the positive active material layer is enhanced, thereby improving the cycle life of the electrolyte under high voltage.
  • Polynitrile compounds with more cyano groups can improve the cycle performance of electrochemical devices, but may lead to storage pressure drop in electrochemical devices. The use of certain dinitrile compounds can suppress the impact on the pressure drop.
  • the electrolyte further includes: an oxygen-containing heterocyclic compound.
  • the oxygen-containing heterocyclic compound can form a relatively stable protective layer on the positive electrode active material layer and the negative electrode active material layer, thereby improving the cycle performance and storage performance of the electrochemical device.
  • the dinitrile compound accounts for C% of the total mass of the electrolyte
  • the polynitrile compound accounts for D% of the total mass of the electrolyte, 0.5 ⁇ D/C ⁇ 20.
  • the storage voltage drop of the electrochemical device is relatively large
  • the value of D/C is less than 0.5
  • the cycle performance of the electrochemical device is deteriorated.
  • the value of /C is greater than 20
  • the content of trinitrile compounds is relatively high. Although the trinitrile compounds can significantly improve the electrical properties, they will affect the storage pressure drop of the electrochemical device.
  • Nitrile compounds can be used to suppress the effect of trinitrile compounds on storage pressure drop, and the addition of dinitrile compounds will also significantly improve the cycle performance.
  • the D/C ratio is less than 0.5, the low content of trinitrile compounds does not significantly improve the cycle. , therefore, in some embodiments, 0.5 ⁇ D/C ⁇ 20 is controlled.
  • the dinitrile compound accounts for C% of the total mass of the electrolyte, and satisfies 0.5 ⁇ C ⁇ 7.
  • the polynitrile compound accounts for D% of the total mass of the electrolyte, and satisfies 0.1 ⁇ D ⁇ 4.
  • the compound represented by formula I and the polynitrile compound satisfy: 0.02 ⁇ A/D ⁇ 130. In some embodiments of the present application, the compound represented by formula I and the polynitrile compound satisfy: 0.1 ⁇ A/D ⁇ 130. In some embodiments of the present application, the compound represented by formula I and the polynitrile compound satisfy: 1 ⁇ A/D ⁇ 130. In some embodiments of the present application, the compound represented by formula I and the polynitrile compound satisfy: 5 ⁇ A/D ⁇ 130. In some embodiments, when the A/D is less than 0.02, the cycle performance and overdischarge storage performance of the electrochemical device are both poor, and when the A/D is greater than 130, the cycle performance of the electrochemical device is poor. In some embodiments, when 0.1 ⁇ A/D ⁇ 130, the cycle performance of the electrochemical device is more excellent.
  • the dinitrile compounds include: succinonitrile, glutaronitrile, adiponitrile, pimeliconitrile, suberonitrile, azelonitrile, sebaconitrile, ethylene glycol (bispropionitrile) ether ( nitrile ether) or at least one of fumaric nitrile.
  • the polynitrile compounds include: 1,3,6-hexanetrinitrile, 1,2,6-hexanetrinitrile, 1,3,5-pentanetrinitrile, nonanetrinitrile, 1,2,6-hexanetrinitrile 3,5-benzenetricarbonitrile, 2,4,6-trifluorobenzene-1,3,5-tricarbonitrile, 1,3,5-cyclohexanetricarbonitrile, 1,2,3-propanetricarbonitrile, 1, At least one of 3,5-benzenetricyano or 1,2,3-tris(2-cyanooxy)propane.
  • the 1,3-propane sultone accounts for 0.1% to 1% of the total mass of the electrolyte.
  • the oxygen-containing heterocyclic compounds include: 1,3-dioxane, dioxolane, 4-methyl-1,3-dioxane, tetrahydropyran, tetrahydrofuran or at least one of 1,2-epoxybutane.
  • the oxygen-containing heterocyclic compound accounts for 0.01% to 3% of the total mass of the electrolyte.
  • the tensile strength of the positive electrode current collector is B MPa, which satisfies B>100.
  • the positive electrode current collector includes aluminum.
  • the positive electrode current collector is an aluminum foil, and the aluminum foil has a low density and high strength, which is beneficial to ensure safety performance while reducing the number of electrochemical devices.
  • the thickness of the positive electrode current collector is 5 ⁇ m to 20 ⁇ m. In some embodiments, when the thickness of the positive electrode current collector is less than 5 ⁇ m, the positive electrode current collector may be easily corroded or fractured, resulting in reduced safety performance, and when the thickness of the positive electrode current collector is greater than 20 ⁇ m, the energy density of the electrochemical device may be reduced.
  • the positive electrode current collector includes M element
  • the M element includes at least one of silicon, copper, manganese, iron, zinc, magnesium, titanium, and vanadium
  • the percentage of M element in the total weight of the positive electrode current collector is not greater than 2%. In some embodiments, when the percentage of M element in the total weight of the positive electrode current collector is greater than 2%, the strength of the positive electrode current collector will be reduced, and the drop performance of the electrochemical device will be reduced.
  • the weight per unit area of the positive electrode current collector is 15 g/m 2 to 100 g/m 2 . In some embodiments, if the weight per unit area of the positive electrode current collector is too small, the strength of the positive electrode current collector may be insufficient, and if the weight per unit area of the positive electrode current collector is too large, the weight of the electrochemical device may increase.
  • the elongation of the positive electrode current collector is greater than or equal to 1%. In some embodiments, when the elongation of the positive electrode current collector is less than 1%, the positive electrode current collector may be easily broken, which reduces the safety performance.
  • the positive electrode current collector has a solder-printed area, and the area of the solder-printed area is F cm 2 , 1 ⁇ F ⁇ 50.
  • the positive electrode includes a positive electrode current collector 2 and a positive electrode active material layer 1 located on the positive electrode current collector 2 , and the positive electrode current collector 2 .
  • the number of solder print areas is greater than or equal to two.
  • the area of the soldering areas is the sum of the areas of all soldering areas.
  • the anode includes an anode current collector and an anode active material layer, the anode active material layer includes an anode material, the anode material includes a silicon-based material, and at least a part of the particle surface of the silicon-based material has a protective layer.
  • the theoretical specific capacity of silicon-based materials reaches 4200mAh/g, which is much higher than the theoretical specific capacity of carbon materials.
  • the specific capacity of the negative electrode material can be improved, but the silicon-based material will have some problems during the charging and discharging process. Larger volume expansion, so at least a part of the particle surface of the silicon-based material has a protective layer, thereby reducing the volume expansion of the silicon-based material and reducing the volume change of the electrochemical device during charging and discharging.
  • the protective layer includes: carbon material or Me x O y , wherein Me includes at least one of Al, Si, Mn, V, Cr, Co or Zr, x is 1 to 2, and y is 1 to 3.
  • the carbon material itself can accommodate lithium ions, and when the protective layer includes the carbon material, on the one hand, the expansion of the silicon-based material can be suppressed, and on the other hand, the capacity of the negative electrode material can be improved, and when the protective layer includes Me x O y , due to Me x O y is a metal oxide with high strength and can well inhibit the expansion of silicon-based materials.
  • the positive electrode current collector may use Al foil, and of course, other positive electrode current collectors commonly used in the art may also be used.
  • the thickness of the cathode current collector may be 1 ⁇ m to 50 ⁇ m.
  • the positive electrode active material layer may only be coated on a partial area of the positive electrode current collector.
  • the thickness of the cathode active material layer may be 10 ⁇ m to 500 ⁇ m. It should be understood that these are exemplary only and other suitable thicknesses may be employed.
  • the release membrane includes at least one of polyethylene, polypropylene, polyvinylidene fluoride, polyethylene terephthalate, polyimide, or aramid.
  • the polyethylene includes at least one selected from high density polyethylene, low density polyethylene or ultra-high molecular weight polyethylene. Especially polyethylene and polypropylene, they have a good effect on preventing short circuits and can improve the stability of the battery through the shutdown effect.
  • the thickness of the isolation film is in the range of about 3 ⁇ m to 50 ⁇ m.
  • the surface of the isolation membrane may further include a porous layer, the porous layer is disposed on at least one surface of the isolation membrane, the porous layer includes inorganic particles and a binder, and the inorganic particles are selected from aluminum oxide (Al 2 O 3 ), Silicon oxide (SiO 2 ), magnesium oxide (MgO), titanium oxide (TiO 2 ), hafnium dioxide (HfO 2 ), tin oxide (SnO 2 ), ceria (CeO 2 ), nickel oxide (NiO), oxide Zinc (ZnO), calcium oxide (CaO), zirconium oxide (ZrO 2 ), yttrium oxide (Y 2 O 3 ), silicon carbide (SiC), boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide or sulfuric acid at least one of barium.
  • the binder of the porous layer is selected from polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, sodium carboxymethyl cellulose, polyamide At least one of vinylpyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene or polyhexafluoropropylene.
  • the porous layer on the surface of the separator can improve the heat resistance, oxidation resistance and electrolyte wettability of the separator, and enhance the adhesion between the separator and the pole piece.
  • the electrochemical device is wound or stacked.
  • the electrochemical device includes a lithium-ion battery, although the present application is not so limited.
  • the electrochemical device may also include an electrolyte.
  • the electrolyte may be one or more of a gel electrolyte, a solid electrolyte, and an electrolytic solution, and the electrolytic solution includes a lithium salt and a non-aqueous solvent.
  • the lithium salt is selected from LiPF 6 , LiBF 4 , LiAsF + , LiClO 4 , LiB(C 6 H 5 ) 4 , LiCH 3 SO 3 , LiCF 3 SO 3 , LiN(SO 2 CF 3 ) 2 , LiC(SO 2 CF 3 ) 3 , LiSiF 6 , LiBOB or one or more of lithium difluoroborate.
  • LiPF 6 is chosen as the lithium salt because it can give high ionic conductivity and improve cycle characteristics.
  • the non-aqueous solvent may be a carbonate compound, a carboxylate compound, an ether compound, other organic solvents, or a combination thereof.
  • the carbonate compound may be a chain carbonate compound, a cyclic carbonate compound, or a combination thereof.
  • chain carbonate compounds are diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), methyl carbonate Ethyl esters (MEC) and combinations thereof.
  • chain carbonate compounds are diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), methyl carbonate Ethyl esters (MEC) and combinations thereof.
  • Examples of the cyclic carbonate compound are ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), vinylethylene carbonate (VEC), or a combination thereof.
  • carboxylate compounds are ethyl acetate, n-propyl acetate, tert-butyl acetate, methyl propionate, ethyl propionate, propyl propionate, gamma-butyrolactone, decanolide, valerolactone, Mevalonolactone, caprolactone, or a combination thereof.
  • ether compounds are dibutyl ether, tetraglyme, diglyme, 1,2-dimethoxyethane, 1,2-diethoxyethane, ethoxymethoxy Ethane, 2-methyltetrahydrofuran, tetrahydrofuran, or a combination thereof.
  • organic solvents examples include dimethyl sulfoxide, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, N-methyl-2-pyrrolidone, formamide, dimethylformamide, acetonitrile , trimethyl phosphate, triethyl phosphate, trioctyl phosphate, and phosphate esters or combinations thereof.
  • Embodiments of the present application also provide electronic devices including the above electrochemical devices.
  • the electronic device in the embodiment 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 input computers, mobile computers, e-book players, portable telephones, portable fax machines, portable copiers, portable printers, headsets, VCRs, LCD TVs, portable cleaners, portable CD players, mini discs, transceivers, electronic notepads, calculators, memory cards, portable recorders, radios, backup power supplies, motors, automobiles, motorcycles, assisted bicycles, bicycles, Lighting equipment, toys, game consoles, clocks, power tools, flashlights, cameras, large-scale household storage batteries and lithium-ion capacitors, etc.
  • positive electrode sheet The positive electrode material lithium cobalt oxide, polyvinylidene fluoride (PVDF), and Super-P were dissolved in N-methylpyrrolidone (NMP) in a mass ratio of 96:2:2 and mixed uniformly to prepare a positive electrode slurry.
  • NMP N-methylpyrrolidone
  • the positive electrode slurry was evenly coated on the positive electrode current collector aluminum foil with a thickness of 12 ⁇ m, baked at 120 °C for 1 h, and then the positive electrode sheet was obtained by compacting, slitting and welding the tabs;
  • Preparation of negative electrode sheet Dissolve the negative electrode material, sodium carboxymethyl cellulose (CMC), and styrene-butadiene rubber in water in a mass ratio of 85:2:13, fully mix and stir to obtain a negative electrode slurry, and evenly coat the negative electrode slurry on the On the negative electrode current collector copper foil with a thickness of 12 ⁇ m, the negative electrode active material layer was obtained by baking at 120 °C for 1 h, and then the negative electrode sheet was obtained by compacting, slitting and welding the tabs;
  • CMC carboxymethyl cellulose
  • styrene-butadiene rubber in water in a mass ratio of 85:2:13
  • Preparation of lithium ion battery 12 ⁇ m polypropylene film was used as separator.
  • the positive electrode sheet, the separator and the negative electrode sheet are stacked in sequence, so that the separator is in the middle of the positive and negative electrodes for isolation, and then rolled into a bare cell.
  • Electrolyte preparation mix ethylene carbonate, propylene carbonate, and diethyl carbonate according to a mass ratio of 3:1:6, then add other additives and lithium salts with different contents on the basis of the above-mentioned electrolyte to obtain the results in each embodiment. the electrolyte used;
  • test methods for the high-temperature cycle performance and safety performance of the lithium-ion batteries prepared in each of the examples and comparative examples are as follows:
  • Cycle performance test Charge the battery to 4.45V at a constant current of 1C at 45°C, let it stand for 30min, discharge it to 3.0V at 1C, cycle charge and discharge 500 times, and record the discharge capacity in China during the cycle;
  • Cycle capacity retention rate (%) 500 discharge capacity/first discharge capacity ⁇ 100%.
  • Over-discharge storage test put the battery in a 25°C incubator, discharge it to 2.0V at a constant current of 0.5C, test the thickness of the battery, and then store the battery in a 60°C high-temperature furnace for 15 days to test the thickness of the battery after storage.
  • Over-discharge storage thickness growth rate (%) (battery thickness after storage-battery thickness before storage)/battery thickness before storage ⁇ 100%.
  • 60°C storage voltage drop test put the battery in a 25°C incubator, charge it to 4.45V with a constant current of 0.5C, and then charge it with a constant voltage to a current of 0.05C, store the battery in a 60°C high temperature box for 30 days, and record The voltage value of the lithium-ion battery after storage.
  • Drop performance test put the battery after the high temperature cycle at 45°C into a 25°C incubator, charge it to 4.45V with a constant current of 0.5C, and then charge it with a constant voltage to a current of 0.05C, and place the battery in an environment of 25°C.
  • Drop test drop the battery from a height of 1 meter to the concrete floor, repeat 3 times for 1 battery, ensure that each random direction is hit when falling, if there is liquid leakage, fire or explosion, it is judged as failure, each group of tests 20 batteries;
  • Drop passing rate (%) number of failed batteries/20 ⁇ 100%.
  • the positive current collector test is as follows:
  • Aluminum foil thickness test use a micrometer to measure 5 points and take the average value.
  • Tensile strength test use a tensile testing machine to test, the length of the test sample is 200 ⁇ 0.5mm, the width is 15 ⁇ 0.25mm, the tensile speed is set to 50mm/min, the distance between the chuck of the testing machine is 125 ⁇ 0.1mm, and the sample is set to 125 ⁇ 0.1mm. The test is stopped when it is stretched to break, and the value of the tensile strength is read. Test 5 parallel samples, and take the average value as the test result. During the test, the length direction of the sample is parallel to the axis of the fixture, and the sample is kept straight. The experimental temperature is 20 ⁇ 5 °C.
  • the electrical performance test data is as follows:
  • Table 1 shows the electrolytes used in Comparative Examples 1 to 3, and Examples 1 to 13 and the performance test results.
  • the Comparative Examples 1 to 3, and Examples 1 to 13 shown in Table 1 13 The positive electrode material used is lithium cobalt oxide, the negative electrode material is a mixture of silicon-based material and graphite, and the silicon-based material is silicon oxide and the mass ratio of silicon-based material and graphite is 1:9; the thickness of the aluminum foil is 10 ⁇ m, and the elongation is ⁇ 1 %, the weight per unit area is 67g/m 2 , the percentage of Cu element in the total weight of the positive electrode current collector is 0.1%, the area F of the solder printing area is 1.2 cm 2 , the content of the compound shown in formula I is A%, the positive electrode current collector draws The tensile strength is 80MPa, the fluorine-containing lithium salt in the electrolyte is lithium hexafluorophosphate, and the content is 12.5%.
  • Example 1 to Example 13 in Table 1 From Comparative Example 1, Example 1 to Example 13 in Table 1, it can be seen that when the compound represented by Formula I is added to the electrolyte, the cycle capacity retention rate of the lithium ion battery increases, the over-discharge storage thickness growth rate decreases and The drop pass rate is increased, that is, the cycle performance and storage performance of the lithium-ion battery are significantly improved.
  • the compounds represented by formula I in Examples 1 to 13 contain F element and carbonate groups, which can continuously form a LiF protective layer on the negative electrode during the cycle process, improve the stability of the negative electrode interface, and thus can significantly improve the lithium ion
  • the cycle performance of the battery at the same time, when the lithium-ion battery is in the over-discharge state, the negative electrode potential increases and the instability increases. Since the compound shown in formula I can effectively repair the negative electrode, it can significantly reduce the gas production during the over-discharge storage process. Improve the safety performance of lithium-ion batteries.
  • Comparative Example 2 when the content of the compound represented by formula I is less than 0.3 and the B/A value is large, the growth rate of the over-discharge storage thickness of the lithium-ion battery is still large, and the storage performance is not good, which may be due to Because the content of the compound shown in formula I is too small, the improvement effect is not obvious. It can be seen from Examples 1 to 6 and Comparative Example 3 that with the increase of the content of the compound shown in formula I, the cycle performance of the lithium ion battery is improved.
  • A is controlled to be 0.3 to 40, and 2 ⁇ B/A ⁇ 750.
  • Table 2 shows the electrolytes used in Examples 14 to 25 and the performance test results.
  • the positive electrode material used in each example in Table 2 is lithium cobalt oxide, and the negative electrode material is a mixture of silicon-based materials and graphite. Silicon
  • the surface layer of the base material is covered with a carbon layer, and the silicon-based material is silicon oxide, and the mass ratio of the silicon-based material and graphite is 1:9, the thickness of the aluminum foil is 10 ⁇ m, the elongation rate is ⁇ 1%, the weight per unit area is 67 g/m 2 , and Cu element
  • the percentage of the total weight of the positive electrode current collector is 0.1%, the area F of the welding area is 1.2 cm 2 , the content of the compound shown in formula I is A%, the tensile strength of the positive electrode current collector is B MPa, and the dinitrile compound in the electrolyte is The mass content of adiponitrile is 1%, the polynitrile compound is 1,3,6-hexanetrinitrile
  • B/A In order to ensure the electrical performance and safety performance of the lithium-ion battery at the same time, the value of B/A needs to be controlled within a certain ratio range, so 2 ⁇ B/A ⁇ 750 is controlled in some embodiments of the present application.
  • Table 3 shows the electrolytes used in Examples 26 to 38 and the performance test results.
  • the positive electrode material used in Table 3 is lithium cobalt oxide
  • the negative electrode material is a mixture of silicon-based material and graphite
  • the surface layer of the silicon-based material is The carbon layer is coated
  • the silicon-based material is silicon oxide and the mass ratio of the silicon-based material and graphite is 1:9
  • the content of the compound shown in formula I in the electrolyte is A%
  • the tensile strength of the positive electrode current collector is 160MPa
  • the thickness of the aluminum foil is 10 ⁇ m, elongation ⁇ 1%, weight per unit area 67g/m 2
  • the area F of the soldering area is 1.2cm 2
  • the fluorine-containing lithium salt is lithium hexafluorophosphate
  • the content is 12.5%.
  • Example 26 Comparing Example 26 to Example 34, it can be seen that when the value of D/C is greater than 20, the storage voltage drop at 60°C of the lithium-ion battery is larger, and when the value of D/C is less than 0.5, the cycle performance of the lithium-ion battery is This may be because the trinitrile compound can significantly improve the electrical properties, but it is easy to cause an increase in the storage voltage drop. Therefore, when the D/C value is greater than 20, the storage voltage drop at 60 °C is large; in order to suppress the three The effect of nitrile compound on storage pressure drop, adding dinitrile compound, and when the D/C ratio is less than 0.5, too low content of trinitrile compound does not significantly improve the cycle performance, resulting in reduced cycle performance. Therefore, 0.5 ⁇ D/C ⁇ 20 is defined in some embodiments, so as to reduce the storage voltage drop while ensuring the cycle performance.
  • Table 4 shows the electrolytes and performance test results used in Examples 39 to 50.
  • the positive electrode material is lithium cobalt oxide
  • the negative electrode material is a mixture of silicon-based material and graphite
  • the silicon-based material is covered with a surface layer Carbon layer
  • the silicon-based material is silicon oxide
  • the mass ratio of silicon-based material and graphite is 1:9
  • the thickness of aluminum foil is 10 ⁇ m
  • the elongation is ⁇ 1%
  • the weight per unit area is 67g/m 2
  • the content of M element is ⁇ 1%
  • the area F of the soldering area is 1.2 cm 2
  • the content of the compound represented by the formula I is A%
  • the tensile strength of the positive electrode current collector is 100 MPa
  • the compound represented by the formula I contained in the electrolyte in the examples shown in Table 4 is fluorine Substituted ethylene carbonate, the content is 5%
  • the dinitrile compounds contained in the electrolyte are succinonitrile and
  • Table 5 shows the electrolytes and performance test results used in Examples 51 to 58.
  • the positive electrode material used in Table 5 is lithium cobalt oxide
  • the negative electrode is a mixture of silicon-based material and graphite
  • the silicon-based material is oxidized
  • the mass ratio of silicon and silicon-based material and graphite is 2:8, the thickness of the aluminum foil is 10 ⁇ m, the elongation is ⁇ 1%, the weight per unit area is 67 g/m 2 , and the tensile strength of the positive electrode current collector is 160 MPa.
  • the compound shown in formula I contained in the electrolytic solution is fluoroethylene carbonate, and the mass content is 5%.
  • the dinitrile compounds contained in the electrolytic solution are succinonitrile and adiponitrile, and the mass content is respectively 1% and 0.5%.
  • the trinitrile contained in the liquid is 1,3,6-hexanetrinitrile with a mass content of 2%, the fluorine-containing lithium salt is lithium hexafluorophosphate with a content of 12.5%, and M is a Cu element.
  • Example 51 Comparing Example 51 to Example 53, it can be seen that when the mass content of M element in the aluminum foil is > 2%, the drop pass rate of the lithium ion battery decreases, which may be because when the content of M element is > 2%, the aluminum foil is caused. The strength decreases, and finally the drop performance deteriorates.
  • Example 54 Comparing Example 54 to Example 58, it can be seen that when the area of the solder printing area is gradually increased, the drop pass rate of the lithium ion battery is significantly reduced, which may be because the solder joints are more easily corroded by the electrolyte, which deteriorates the drop performance.
  • Example 51 Comparing Example 51 and Example 57, it can be seen that when the negative electrode material uses a silicon material without a coating layer, the cycle capacity retention rate of the lithium ion battery is significantly reduced, and the over-discharge storage thickness growth rate is significantly increased. It can be seen that, Using a silicon material with a coating layer can significantly improve the electrical performance of a lithium-ion battery using a silicon material negative electrode.

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Abstract

本申请一种电化学装置和电子装置，电化学装置包括：正极、负极、隔离膜和电解液；电解液，包括式I所示化合物。其中，式Ⅰ所示化合物占电解液总质量的A％，A为0.3至40；R1、R2各自独立地选自氢、卤素、碳原子数为1至5的烷基、被卤素取代的碳原子数为1至5的烷基、碳原子数为1至5的烯基或被卤素取代的碳原子数为1至5的烯基；且R1、R2中至少一者含有卤素；正极包括正极集流体和设置于正极集流体至少一个表面上的正极活性物质层，正极集流体的拉伸强度为BMPa，且2≤B/A≤750。本申请能够提高电化学装置的循环性能和过放存储性能，并在长时间的循环后保持较好的安全性能。

Description

电化学装置和电子装置
相关申请的交叉引用
本申请基于申请号为202110340358.9、申请日为2021年03月30日，名称为“电化学装置和电子装置”的中国专利申请提出，并要求该中国专利申请的优先权，该中国专利申请的全部内容在此引入本申请作为参考。
技术领域
本申请涉及电化学技术领域，尤其涉及一种电化学装置和电子装置。
背景技术
电化学装置(例如：锂离子电池)被广泛应用在各个领域的电子设备中，随着电子设备的发展，人们对电化学装置的能量密度提出了更高的要求。
另一方面，各种电子产品使用的安全问题层出不穷，不仅需要考虑电化学装置的使用寿命，同时还关注它的使用安全性，因此如何在保证电化学装置的循环性能，同时提高电化学装置的安全性成为一个急待解决的问题。
发明内容
本申请提供一种电化学装置和电子装置，能够在改善电化学装置的循环性能和过放存储性能的同时，降低电解液对正极集流体的腐蚀，保证电化学装置的安全性能。
本申请一些实施例中提出一种电化学装置，包括：正极、负极、隔离膜和电解液；电解液，包括式I所示化合物：
Figure PCTCN2021104955-appb-000001
其中，式Ⅰ所示化合物占电解液总质量的A％，A为0.3至40；R 1、R 2各自独立地选自氢、卤素、碳原子数为1至5的烷基、被卤素取代的碳原子数 为1至5的烷基、碳原子数为1至5的烯基或被卤素取代的碳原子数为1至5的烯基，碳原子数为1至5的炔基或被卤素取代的碳原子数为1至5的炔基；且R 1、R 2中至少一者含有卤素；正极包括正极集流体和设置于正极集流体至少一个表面上的正极活性物质层，正极集流体的拉伸强度为B MPa，且2≤B/A≤750。
本申请一些实施例中，式I所示化合物包括：氟代碳酸乙烯酯、双氟代碳酸乙烯酯、甲基氟代碳酸乙烯酯或4-氟-5-甲基碳酸乙烯酯中的至少一种。
本申请一些实施例中，满足如下条件(a)至(d)中的至少一种：
(a)电解液中还包括：二腈化合物；
(b)电解液中还包括：氰基数量大于等于3的多腈化合物；
(c)电解液中还包括：含S＝O双键的化合物；
(d)电解液中还包括：含氧杂环化合物。
本申请一些实施例中，二腈化合物占电解液总质量的C％，多腈化合物占电解液总质量的D％，0.5≤D/C≤20；
本申请一些实施例中，二腈化合物占电解液总质量的C％，满足0.5≤C≤7。
本申请一些实施例中，多腈化合物占电解液总质量的D％，满足0.1≤D≤4。
本申请一些实施例中，式Ⅰ化合物与多腈化合物满足：0.02≤A/D≤130。
本申请一些实施例中，二腈化合物包括：丁二腈、戊二腈、己二腈、庚二腈、辛二腈、壬二腈、癸二腈，乙二醇(双丙腈)醚(腈醚)或反丁烯二腈中的至少一种；
本申请一些实施例中，多腈化合物包括：1,3,6-己烷三腈、1,2,6-己烷三腈、1,3,5-戊烷三腈、壬三腈、1,3,5-苯三腈、2,4,6-三氟苯-1,3,5-三腈、1,3,5-环己三腈、1,2,3-丙三甲腈、1,3,5-苯三氰基或1,2,3-三(2-氰氧基)丙烷中的至少一种。
本申请一些实施例中，含S＝O双键的化合物包括：1,3-丙烷磺酸内酯、2,4-丁烷磺酸内酯、1,4-丁烷磺酸内酯、甲烷二磺酸亚甲酯、硫酸乙烯酯、环丁砜、硫酸丙烯酯、4-甲基硫酸亚乙酯或5-甲基恶噻戊环2,2-二氧化物中的至少一种。
本申请一些实施例中，含S＝O双键的化合物占电解液总质量的0.1％至7％。
本申请一些实施例中，含氧杂环化合物包括：1,3-二氧杂环己烷、二氧戊环、4-甲基-1,3-二氧六环、四氢吡喃、四氢呋喃或1,2-环氧丁烷中的至少一种。
本申请一些实施例中，含氧杂环化合物占电解液总质量的0.01％至3％。
本申请一些实施例中，正极集流体的拉伸强度为B MPa，满足B>100。
本申请一些实施例中，正极集流体满足条件(e)至(j)中的至少一种：
(e)正极集流体包含铝；
(f)正极集流体厚度为5μm至20μm；
(g)正极集流体包含M元素，M元素包括硅、铜、锰、铁、锌、镁、钛、钒中的至少一种，M元素占正极集流体总重量的百分比不大于2％；
(h)正极集流体单位面积重量为15g/m 2至100g/m 2；
(i)正极集流体的延伸率≥1％；
(j)正极集流体上具有焊印区域，焊印区域的面积为F cm 2，1≤F≤50。
本申请一些实施例中，负极包括负极集流体和负极活性物质层，负极活性物质层包括负极材料，负极材料包括硅基材料，硅基材料的颗粒表面的至少一部分区域上具有保护层。
本申请一些实施例中，保护层包括：碳材料或Me xO y，其中，Me包括Al、Si、Mn、V、Cr、Co或Zr中的至少一种，x为1至2，y为1至3。
本申请的一些实施例中提出一种电子装置，包括上述任一项的电化学装置。
本申请实施例提供的电化学装置中包括式I所示化合物，式I所示化合物可在电化学装置过放存储过程持续修复负极SEI(solid electrolyte interphase，固体电解质界相)膜，有效改善负极界面，减少过放存储胀气并改善循环性能，并且，通过将正极集流体的拉伸强度和式I所示化合物含量的比值控制在一定范围内。本申请可保证电化学装置的循环性能和过放存储性能，又可提高电化学装置的安全性能。
附图说明
结合附图并参考以下具体实施方式，本公开各实施例的上述和其他特征、优点及方面将变得更加明显。贯穿附图中，相同或相似的附图标记表示相同或相似的元素。应当理解附图是示意性的，元件和元素不一定按照比例绘制。
图1是本公开实施例的正极和极耳的连接示意图。
具体实施方式
下面将更详细地描述本申请的实施例。本申请可以通过各种形式来实现，而且不应该被解释为限于这里阐述的实施例，相反提供这些实施例是为了更加透彻和完整地理解本申请。
相关技术中，在电解液中添加含氟添加剂，例如FEC，从而提高负极体系电化学装置的循环性能，然而，FEC能够与六氟磷酸锂反应生成腐蚀性成分腐蚀正极集流体，例如铝箔，导致电化学装置的跌落性能、撞击性能等安全性能降低。
为了至少部分解决上述问题，本申请一些实施例中提出一种电化学装置，包括：正极、负极、隔离膜和电解液；电解液，包括式I所示化合物：
Figure PCTCN2021104955-appb-000002
其中，式Ⅰ所示化合物占电解液总质量的A％，A为0.3至40；R 1、R 2各自独立地选自氢基、卤素、碳原子数为1至5的烷基、被卤素取代的碳原子数为1至5的烷基、碳原子数为1至5的烯基或被卤素取代的碳原子数为1至5的烯基、碳原子数为1至5的炔基或被卤素取代的碳原子数为1至5的炔基；且R 1、R 2中至少一者含有卤素；正极包括正极集流体和设置于正极集流体至少一个表面上的正极活性物质层，正极集流体的拉伸强度为B MPa，且2≤B/A≤750。一些实施例中，负极包括负极集流体和设置于负极集流体至少一个表面上的负极活性物质层。
在本申请的一些实施例中，一方面通过在电解液中加入式I所示的化合物，从而能够在电化学装置过放存储过程中持续修复负极的SEI膜，有效改善负极界面，降低过放存储胀气并改善循环性能。另一方面，为了解决式I 所示化合物与水反应后的产物对正极集流体腐蚀造成的安全性能降低的问题，本申请中控制正极集流体的拉伸强度与式I所示化合物的含量的比值，正极集流体能保持一定的拉伸强度，提高循环后电化学装置的跌落性能和撞击性能。因此，本申请提出的电化学装置，能够在保证电化学装置的循环性能和过放存储性能的同时，降低电解液对正极集流体的腐蚀，使得正极集流体长时间高温下保持一定的拉伸强度，提高电化学装置的安全性能。
本申请一些实施例中，式I所示化合物包括：氟代碳酸乙烯酯、双氟代碳酸乙烯酯、甲基氟代碳酸乙烯酯或4-氟-5-甲基碳酸乙烯酯中的至少一种。本申请一些实施例中，式I所示化合物的含量为0.1％至40％。本申请一些实施例中，式I所示化合物的含量为1％至20％。本申请一些实施例中，式I所示化合物的含量为4％至20％。上述化合物能够优先与负极活性物质层形成稳定的SEI膜，从而保护负极活性物质层。
本申请一些实施例中，电解液中还包括：二腈化合物。
本申请一些实施例中，电解液中还包括：氰基数量大于等于3的多腈化合物。
一些实施例中，氰基键能很高，不容易被氧化，腈类化合物在正极上具有很好的稳定性，耐氧化性很强，同时，氰基又具有较强的配位能力,可以和正极活性物质层表面的活性位点结合，减少正极活性物质层对电解液的分解作用，增强电解液对正极活性物质层氧化的抵抗能力，从而提高电解液在高电压下的循环寿命。多腈化合物具有较多的氰基能够改善电化学装置的循环性能，但可能导致电化学装置发生存储压降，使用一定的二腈化合物可以抑制对压降的影响。
本申请一些实施例中，电解液中还包括：含S＝O双键的化合物。一些实施例中，含S＝O双键的化合物能够在正极活性物质层和负极活性物质层形成较为稳定的保护层，从而改善电化学装置的循环性能和存储性能。
本申请一些实施例中，电解液中还包括：含氧杂环化合物。一些实施例中，含氧杂环化合物能够在正极活性物质层和负极活性物质层形成较为稳定的保护层，从而改善电化学装置的循环性能和存储性能。
本申请一些实施例中，二腈化合物占电解液总质量的C％，多腈化合物占电解液总质量的D％，0.5≤D/C≤20。一些实施例中，当D/C的值大于20时， 电化学装置的存储压降较大，当D/C的值小于0.5时，电化学装置的循环性能变差，可能的原因是当D/C的值大于20时，三腈化合物含量较高，三腈化合物虽然对电性能有显著改善，但影响电化学装置存储压降，因此当添加一定含量的三腈化合物时，需添加部分二腈化合物来抑制三腈化合物对存储压降的影响，同时二腈化合物的加入也会对循环性能有明显改善，而当D/C比值小于0.5时，低含量的三腈对循环的改善不显著，因此，一些实施例中控制0.5≤D/C≤20。
本申请一些实施例中，二腈化合物占电解液总质量的C％，满足0.5≤C≤7。
本申请一些实施例中，多腈化合物占电解液总质量的D％，满足0.1≤D≤4。
本申请一些实施例中，式Ⅰ所示化合物与多腈化合物满足：0.02≤A/D≤130。本申请一些实施例中，式Ⅰ所示化合物与多腈化合物满足：0.1≤A/D≤130。本申请一些实施例中，式Ⅰ所示化合物与多腈化合物满足：1≤A/D≤130。本申请一些实施例中，式Ⅰ所示化合物与多腈化合物满足：5≤A/D≤130。一些实施例中，当A/D小于0.02时，电化学装置的循环性能和过放存储性能均较差，而当A/D大于130时，电化学装置的循环性能不佳。一些实施例中，当0.1≤A/D≤130时，电化学装置的循环性能更优异。
本申请一些实施例中，二腈化合物包括：丁二腈、戊二腈、己二腈、庚二腈、辛二腈、壬二腈、癸二腈，乙二醇(双丙腈)醚(腈醚)或反丁烯二腈中的至少一种。
本申请一些实施例中，多腈化合物包括：1,3,6己烷三腈、1,2,6-己烷三腈、1,3,5-戊烷三腈、壬三腈、1,3,5-苯三腈、2,4,6-三氟苯-1,3,5-三腈、1,3,5-环己三腈、1,2,3-丙三甲腈、1,3,5-苯三氰基或1,2,3-三(2-氰氧基)丙烷中的至少一种。
本申请一些实施例中，含S＝O双键的化合物包括：1,3-丙烷磺酸内酯、2,4-丁烷磺酸内酯、1,4-丁烷磺酸内酯、甲烷二磺酸亚甲酯、硫酸乙烯酯、环丁砜、硫酸丙烯酯、4-甲基硫酸亚乙酯或5-甲基恶噻戊环2,2-二氧化物中的至少一种。
本申请一些实施例中，含S＝O双键的化合物占电解液总质量的0.01％至3％。
本申请一些实施例中，当含S＝O双键的化合物包含1,3-丙烷磺酸内酯时，1,3-丙烷磺酸内酯的占电解液总质量的0.1％至1％。
本申请一些实施例中，含氧杂环化合物包括：1,3-二氧杂环己烷、二氧戊环、4-甲基-1,3-二氧六环、四氢吡喃、四氢呋喃或1,2-环氧丁烷中的至少一种。
本申请一些实施例中，含氧杂环化合物占电解液总质量的0.01％至3％。
本申请一些实施例中，正极集流体的拉伸强度为B MPa，满足B>100。
本申请一些实施例中，正极集流体包含铝。一些实施例中，正极集流体为铝箔，铝箔密度小，强度高，有利于在减少电化学装置的同时保证安全性能。
本申请一些实施例中，正极集流体厚度为5μm至20μm。一些实施例中，当正极集流体厚度小于5μm时，可能导致正极集流体易于被腐蚀或断裂，造成安全性能降低，当正极集流体的厚度大于20μm时，可能造成电化学装置的能量密度降低。
本申请一些实施例中，正极集流体包含M元素，M元素包括硅、铜、锰、铁、锌、镁、钛、钒中的至少一种，M元素占正极集流体总重量的百分比不大于2％。一些实施例中，M元素占正极集流体总重量的百分比大于2％时，会造成正极集流体的强度降低，造成电化学装置的跌落性能降低。
本申请一些实施例中，正极集流体单位面积重量为15g/m 2至100g/m 2。一些实施例中，正极集流体的单位面积重量过小可能造成正极集流体的强度不足，而正极集流体的单位面积重量过大可能造成电化学装置的重量增加。
本申请一些实施例中，正极集流体的延伸率≥1％。一些实施例中，正极集流体的延伸率小于1％时可能造成正极集流体容易断裂，降低安全性能。
本申请一些实施例中，正极集流体上具有焊印区域，焊印区域的面积为F cm 2，1≤F≤50。一些实施例中，如图1所示，图1示意性的显示了正极与极耳的连接示意图，正极包括正极集流体2和位于正极集流体2上的正极活性物质层1，正极集流体2的留白区域上具有焊印区域4(虚线框所示区域)，焊印区域4为极耳3与正极集流体2焊接后形成的，由焊点限定形成的区域，正极集流体需要与极耳相互焊接，当焊印区域的面积太小时可能造成焊点连 接强度不够，当焊印区域的面积太大时，焊点处更容易被电解液腐蚀，造成跌落性能恶化。
本申请一些实施例中，焊印区域的数量大于等于2。当焊印区域的数量大于等于2时，焊印区域的面积为所有焊印区域面积的总和。
本申请一些实施例中，负极包括负极集流体和负极活性物质层，负极活性物质层包括负极材料，负极材料包括硅基材料，硅基材料的颗粒表面的至少一部分区域上具有保护层。硅基材料的理论比容量达到4200mAh/g，远高于碳材料的理论比容量，通过在负极材料中加入硅基材料能够提高负极材料的比容量，但是硅基材料在充放电过程中会有较大的体积膨胀，因此硅基材料的颗粒表面的至少一部分区域上具有保护层，从而减少硅基材料的体积膨胀，减少电化学装置在充放电过程的体积变化。
本申请一些实施例中，保护层包括：碳材料或Me xO y，其中，Me包括Al、Si、Mn、V、Cr、Co或Zr中的至少一种，x为1至2，y为1至3。一些实施例中，碳材料本身能够容纳锂离子，保护层包括碳材料时一方面能够抑制硅基材料膨胀，另一方面能够提高负极材料的容量，而当保护层包括Me xO y时，由于Me xO y为金属氧化物，强度较高，能够很好的抑制硅基材料膨胀。
在一些实施例中，正极集流体可以采用Al箔，当然，也可以采用本领域常用的其他正极集流体。在一些实施例中，正极集流体的厚度可以为1μm至50μm。在一些实施例中，正极活性物质层可以仅涂覆在正极集流体的部分区域上。在一些实施例中，正极活性物质层的厚度可以为10μm至500μm。应该理解，这些仅是示例性的，可以采用其他合适的厚度。
在一些实施例中，隔离膜包括聚乙烯、聚丙烯、聚偏氟乙烯、聚对苯二甲酸乙二醇酯、聚酰亚胺或芳纶中的至少一种。例如，聚乙烯包括选自高密度聚乙烯、低密度聚乙烯或超高分子量聚乙烯中的至少一种。尤其是聚乙烯和聚丙烯，它们对防止短路具有良好的作用，并可以通过关断效应改善电池的稳定性。在一些实施例中，隔离膜的厚度在约3μm至50μm的范围内。
在一些实施例中，隔离膜表面还可以包括多孔层，多孔层设置在隔离膜的至少一个表面上，多孔层包括无机颗粒和粘结剂，无机颗粒选自氧化铝(Al 2O 3)、氧化硅(SiO 2)、氧化镁(MgO)、氧化钛(TiO 2)、二氧化铪 (HfO 2)、氧化锡(SnO 2)、二氧化铈(CeO 2)、氧化镍(NiO)、氧化锌(ZnO)、氧化钙(CaO)、氧化锆(ZrO 2)、氧化钇(Y 2O 3)、碳化硅(SiC)、勃姆石、氢氧化铝、氢氧化镁、氢氧化钙或硫酸钡中的至少一种。多孔层的粘结剂选自聚偏氟乙烯、偏氟乙烯-六氟丙烯的共聚物、聚酰胺、聚丙烯腈、聚丙烯酸酯、聚丙烯酸、聚丙烯酸盐、羧甲基纤维素钠、聚乙烯呲咯烷酮、聚乙烯醚、聚甲基丙烯酸甲酯、聚四氟乙烯或聚六氟丙烯中的至少一种。隔离膜表面的多孔层可以提升隔离膜的耐热性能、抗氧化性能和电解质浸润性能，增强隔离膜与极片之间的粘接性。
在本申请的一些实施例中，电化学装置为卷绕式或堆叠式。
在一些实施例中，电化学装置包括锂离子电池，但是本申请不限于此。在一些实施例中，电化学装置还可以包括电解质。电解质可以是凝胶电解质、固态电解质和电解液中的一种或多种，电解液包括锂盐和非水溶剂。锂盐选自LiPF 6、LiBF 4、LiAsF +、LiClO 4、LiB(C 6H 5) 4、LiCH 3SO 3、LiCF 3SO 3、LiN(SO 2CF 3) 2、LiC(SO 2CF 3) 3、LiSiF 6、LiBOB或者二氟硼酸锂中的一种或多种。例如，锂盐选用LiPF 6，因为它可以给出高的离子导电率并改善循环特性。
非水溶剂可为碳酸酯化合物、羧酸酯化合物、醚化合物、其它有机溶剂或它们的组合。
碳酸酯化合物可为链状碳酸酯化合物、环状碳酸酯化合物或其组合。
链状碳酸酯化合物的实例为碳酸二乙酯(DEC)、碳酸二甲酯(DMC)、碳酸二丙酯(DPC)、碳酸甲丙酯(MPC)、碳酸乙丙酯(EPC)、碳酸甲乙酯(MEC)及其组合。所述环状碳酸酯化合物的实例为碳酸亚乙酯(EC)、碳酸亚丙酯(PC)、碳酸亚丁酯(BC)、碳酸乙烯基亚乙酯(VEC)或者其组合。
羧酸酯化合物的实例为乙酸乙酯、乙酸正丙酯、乙酸叔丁酯、丙酸甲酯、丙酸乙酯、丙酸丙酯、γ-丁内酯、癸内酯、戊内酯、甲瓦龙酸内酯、己内酯或者其组合。
醚化合物的实例为二丁醚、四甘醇二甲醚、二甘醇二甲醚、1,2-二甲氧基乙烷、1,2-二乙氧基乙烷、乙氧基甲氧基乙烷、2-甲基四氢呋喃、四氢呋喃或者其组合。
其它有机溶剂的实例为二甲亚砜、环丁砜、甲基环丁砜、1,3-二甲基-2-咪唑烷酮、N-甲基-2-吡咯烷酮、甲酰胺、二甲基甲酰胺、乙腈、磷酸三甲酯、磷酸三乙酯、磷酸三辛酯、和磷酸酯或者其组合。
本申请的实施例还提供了包括上述电化学装置的电子装置。本申请实施例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。
为使本申请的目的、技术方案和优点更加清楚，下面将结合本申请具体实施例，对本申请的技术方案进行清楚、完整地描述，显然，所描述的实施例是本申请一部分实施例，而不是全部的实施例。基于本申请提供的技术方案及所给出的实施例，本领域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，都属于本申请保护的范围。
正极片制备：将正极材料钴酸锂、聚偏二氟乙烯(PVDF)、Super-P按质量比96：2：2溶于N-甲基吡咯烷酮(NMP)中混合均匀制成正极浆料。将正极浆料均匀地涂布在厚度为12μm的正极集流体铝箔上，120℃烘烤1h，之后经过压实、分切、焊接极耳得到正极片；
负极片制备：将负极材料、羧甲基纤维素钠(CMC)、丁苯橡胶按质量比85：2：13溶于水中，充分混合搅拌得到负极浆料，将负极浆料均匀地涂布在厚度为12μm的负极集流体铜箔上，在120℃烘烤1h得到负极活性材料层，之后经过压实、分切、焊接极耳得到负极片；
锂离子电池制备：以12μm的聚丙烯薄膜作为隔离膜。将正极片、隔离膜、负极片按顺序叠好，使隔离膜处于正负极中间起到隔离的作用，然后卷绕成裸电芯。将裸电芯装入铝箔包装袋，在80℃烘烤除水后，制得干电芯，注入相应电解液，经过真空封装、静置、化成、整形等工序，即完成锂离子电池的制备；
电解液制备：将碳酸乙烯酯、碳酸丙烯酯、碳酸二乙酯按照质量比3：1：6混合，之后在上述电解液的基础上加入不同含量其它添加剂和锂盐，得到各个实施例中所使用的电解液；
对各个实施例和对比例中所制备锂离子电池的高温循环性能和安全性能的测试方法如下：
循环性能测试：将电池在45℃条件下，以恒定电流1C充电至4.45V，静置30min，1C放电至3.0V，循环充放电500次，记录循环过程中国放电容量；
循环容量保持率(％)＝500次放电容量/首次放电容量×100％。
过放存储测试：将电池放至25℃恒温箱中，以恒定电流0.5C放电至2.0V，测试电池厚度，然后将电池于60℃高温炉中存储15天，测试存储后的电池厚度。
过放存储厚度增长率(％)＝(存储后电池厚度-存储前电池厚度)/存储前电池厚度×100％。
60℃存储压降测试：将电池放至25℃恒温箱中，以恒定电流0.5C充电至4.45V,然后恒压充电至电流为0.05C，将电池至于60℃高温箱中存储30天，记录存储后锂离子电池的电压值。
60℃存储压降＝4.45V-存储后锂离子电池的电压值。
跌落性能测试：将45℃高温循环后的电池放至25℃恒温箱中，以恒定电流0.5C充电至4.45V，然后恒压充电至电流为0.05C，将电池放置在25℃的环境下进行跌落测试，将电池从1米的高度跌落至混凝土地板上，1颗电池重复进行3次，跌落时保证每个随机方向受到撞击，若有漏液、着火或爆炸则判定为失效，每组测试20颗电池；
跌落通过率(％)＝失效电池颗数/20×100％。
正极集流体测试如下：
铝箔厚度测试：使用千分尺测量5个点后取平均值。
单位面积质量：将铝箔切成100mm×100mm的片料称重，计算单位面积质量，取5次样，计算平均值，单位面积质量＝重量/面积。
拉伸强度测试：使用拉伸试验机测试，测试样本长度为200±0.5mm，宽度为15±0.25mm，设置50mm/min的拉伸速度，试验机夹头距离为125±0.1mm，将样品拉伸至断裂即停止测试，读取拉伸强度的值。测试5个平行样，取平 均值为测试结果，测试时试样长度方向与夹具轴线平行，并保持样品直线状，实验温度为20±5℃。
延伸率测试：使用拉伸试验机测试，测试样本长度为200±0.5mm，宽度为15±0.25mm，设置50mm/min的拉伸速度，试验机夹头距离为125±0.1mm，将样品拉伸至断裂即停止测试，记录拉伸长度，测试5个平行样，取平均值为测试结果，测试时试样长度方向与夹具轴线平行，并保持样品直线状，实验温度为20±5℃；延伸率＝拉伸长度/样本长度。
电性能测试数据如下所示：
表1展示了对比例1至对比例3、实施例1至实施例13所采用的电解液以及性能测试结果，在表1中所示的对比例1至对比例3、实施例1至实施例13采用的正极材料为钴酸锂，负极材料为硅基材料和石墨的混合物，且硅基材料为氧化硅且硅基材料和石墨的质量比为1:9；铝箔厚度10μm，延伸率≥1％，单位面积重量为67g/m 2，Cu元素占正极集流体总重量的百分比为0.1％，焊印区域面积F为1.2cm 2，式I所示化合物的含量为A％，正极集流体拉伸强度为80MPa，电解液中含氟锂盐为六氟磷酸锂，含量为12.5％。
表1
Figure PCTCN2021104955-appb-000003
Figure PCTCN2021104955-appb-000004
从表1中的对比例1、实施例1至实施例13可以看出，当电解液中加入式I所示化合物后，锂离子电池的循环容量保持率增加、过放存储厚度增长率降低且跌落通过率提高，即锂离子电池的循环性能和存储性能得到明显改善。这是因实施例1至实施例13中式I所示化合物中含有F元素和碳酸根基团，其可以在循环过程在负极持续形成LiF保护层，改善负极界面的稳定性，因此可显著改善锂离子电池的循环性能，同时，在锂离子电池处于过放状态时，负极电位提升，不稳定性增强，由于式I所示化合物能够有效修复负极，因此可明显减少过放存储过程中的产气，提高锂离子电池的安全性能。
从对比例2可以看出，当式I所示化合物的含量少于0.3，B/A数值较大时，锂离子电池的过放存储厚度增长率仍然较大，存储性能不佳，这可能是因为式I所示化合物的含量太少导致改善效果不明显，从实施例1至实施例6以及对比例3可以看出，随着式I所示化合物的含量的提升，锂离子电池的循环性能和存储性能改善显著，但跌落通过率可能会降低，由初始的100％的通过率开始下降，如对比例3所示，当式I所示化合物的含量达到41％时，跌落通过率仅有70％，这是因为在高温下，锂离子电池中的式I所示化合物脱氟生成大量的HF，并不停腐蚀铝箔表层造成铝箔强度降低，最终导致跌落通过率降至70％，严重影响锂离子电池在使用过程的安全性，因此，一些实施例中控制A为0.3至40，2≤B/A≤750。
从实施例7至实施例13可以看出，单独使用满足式I所示结构式的化合物或混合使用不同种类满足式I所示结构式的化合物时，都能够在保证锂离子电池的循环性能的同时，提高锂离子电池的安全性能。
表2展示了实施例14至实施例25中所采用的电解液以及性能测试结果，表2中各个实施例所使用的正极材料为钴酸锂，负极材料为硅基材料和石墨的混合物，硅基材料表层包覆碳层，且硅基材料为氧化硅且硅基材料和石墨的质量比为1:9，铝箔厚度10μm，延伸率≥1％，单位面积重量为67g/m 2，Cu元素占正极集流体总重量的百分比为0.1％，焊印区域面积F为1.2cm 2， 式I所示化合物的含量为A％，正极集流体拉伸强度为B MPa，电解液中二腈化合物为己二腈质量含量为1％，多腈化合物为1,3,6-己烷三腈质量含量为2％；含氟锂盐为六氟磷酸锂，含量为12.5％。
表2
Figure PCTCN2021104955-appb-000005
对比表2所展示的实施例14至实施例20可以看出，随着铝箔拉伸强度的提高，当B/A的值在实施例16至实施例25所示的范围时，锂离子电池的循环性能、存储性能和跌落性能都较优。
为了同时保证锂离子电池的电性能及安全性能，需要控制B/A的值在一定比例范围，因此在本申请的一些实施例中控制2≤B/A≤750。
表3展示了实施例26至实施例38中所采用的电解液以及性能测试结果，表3中使用的正极材料为钴酸锂，负极材料为硅基材料和石墨的混合物，且硅基材料表层包覆碳层，且硅基材料为氧化硅且硅基材料和石墨的质量比为1:9，电解液中式I所示化合物的含量为A％，正极集流体拉伸强度为 160MPa，铝箔厚度10μm，延伸率≥1％，单位面积重量为67g/m 2，Cu元素占正极集流体总重量的百分比<1％，焊印区域面积F为1.2cm 2，含氟锂盐为六氟磷酸锂，含量为12.5％。
表3
Figure PCTCN2021104955-appb-000006
从表3中的实施例35至实施例38可以看出，当电解液中只包括三腈化合物时，锂离子电池的60℃存储压降较大。从表3中的实施例26至实施例34可以看出，当电解液中同时包括二腈化合物和三腈化合物时，可以减小锂离子电池的60℃存储压降。
对比实施例26至实施例34可以看出，当D/C的值大于20时，锂离子电池的60℃存储压降较大，当D/C的值小于0.5时，锂离子电池的循环性能较差，这可能是因为三腈化合物虽然对电性能有显著改善，但易造成存储压降的升高，因此当D/C的值大于20时，60℃存储压降较大；为了抑制三腈化合物对存储压降的影响，加入二腈化合物，而当D/C比值小于0.5时，过低含量的三腈化合物对循环性能的改善不显著，造成循环性能降低。因此，一些实施例中限定0.5≤D/C≤20，从而在保证循环性能的同时减小存储压降。
表4展示了实施例39至实施例50中所采用的电解液以及性能测试结果，表4中正极材料为钴酸锂，负极材料为硅基材料和石墨的混合物，且硅基材料表层包覆碳层，且硅基材料为氧化硅且硅基材料和石墨的质量比为1:9，铝箔厚度10μm，延伸率≥1％，单位面积重量为67g/m 2，M元素含量<1％，焊印区域面积F为1.2cm 2，式I所示化合物的含量为A％，正极集流体拉伸强度为100MPa，表4所示实施例中的电解液中包含的式I所示化合物为氟代碳酸乙烯酯，含量都为5％，电解液中包含的二腈化合物为丁二腈和己二腈，质量含量分别为1％和0.5％，电解液中包含的三腈化合物为1,3,6-己烷三腈，质量含量为2％，含氟锂盐为六氟磷酸锂，含量为12.5％。
表4
Figure PCTCN2021104955-appb-000007
Figure PCTCN2021104955-appb-000008
从实施例39至实施例44可以看出，当电解液中加入了含S＝O双键的化合物或者含氧杂环化合物时，锂离子电池的循环容量保持率均较高，过放存储厚度增长率均较低，且60℃存储压降较小，即当电解液中加入了含S＝O双键的化合物或者含氧杂环化合物时，可以改善锂离子电池的电性能，这可能是因为含S＝O双键的化合物或者含氧杂环化合物都可以在正负极形成稳定的SEI膜，从而提高对正负极的保护，最终改善锂离子电池的电性能。从实施例45至实施例50可以看出，当电解液中同时具有含S＝O双键的化合物和含氧杂环化合物时，锂离子电池的循环容量保持率更高，且过放存储厚度增长率更低，且60℃存储压降更小。
表5展示了实施例51至实施例58所采用的电解液以及性能测试结果，表5中所采用的正极材料为钴酸锂，负极为硅基材料和石墨的混合物，且硅基材料为氧化硅且硅基材料和石墨的质量比为2:8，铝箔厚度10μm，延伸率≥1％，单位面积重量为67g/m 2，正极集流体拉伸强度为160MPa，表5中各个实施例中电解液中包含的式I所示化合物为氟代碳酸乙烯酯，质量含量为5％，电解液中包含的二腈化合物为丁二腈和己二腈，质量含 量分别为1％和0.5％，电解液中包含的三腈为1,3,6-己烷三腈，质量含量为2％，含氟锂盐为六氟磷酸锂，含量为12.5％，M为Cu元素。
表5
Figure PCTCN2021104955-appb-000009
对比实施例51至实施例53可以看出，当铝箔中的M元素质量含量>2％时，锂离子电池的跌落通过率降低，这可能是因为当M元素的含量>2％时，造成铝箔强度的降低，最终跌落性能恶化。
对比实施例54至实施例58可以看出，当焊印区域面积逐渐增大时，锂离子电池的跌落通过率明显降低，这可能是因为焊点处更容易被电解液腐蚀，恶化跌落性能。
对比实施例51和实施例57可以看出，当负极材料使用无包覆层的硅材料时，锂离子电池的循环容量保持率明显降低，且过放存储厚度增长率明显增高，由此可见，使用具有包覆层的硅材料，可显著改善使用硅材料负极的锂离子电池的电性能。
以上描述仅为本申请的较佳实施例以及对所运用技术原理的说明。本领域技术人员应当理解，本申请中所涉及的公开范围，并不限于上述技术特征的特定组合而成的技术方案，同时也应涵盖由上述技术特征或其等同特征进行任意组合而形成的其它技术方案。例如上述特征与本申请中公开的具有类似功能的技术特征进行互相替换而形成的技术方案。

Claims (10)

  1. 一种电化学装置，其特征在于，包括：
    正极、负极、隔离膜和电解液；
    所述电解液，包括式I所示化合物：
    Figure PCTCN2021104955-appb-100001
    其中，所述式Ⅰ所示化合物占所述电解液总质量的A％，A为0.3至40；R 1、R 2各自独立地选自氢、卤素、碳原子数为1至5的烷基、被卤素取代的碳原子数为1至5的烷基、碳原子数为1至5的烯基、被卤素取代的碳原子数为1至5的烯基、碳原子数为1至5的炔基或被卤素取代的碳原子数为1至5的炔基；且R 1、R 2中至少一者含有卤素；
    所述正极包括正极集流体和设置于所述正极集流体至少一个表面上的正极活性物质层，所述正极集流体的拉伸强度为B MPa，且2≤B/A≤750。
  2. 根据权利要求1所述的电化学装置，其特征在于，所述式I所示化合物包括：氟代碳酸乙烯酯、双氟代碳酸乙烯酯、甲基氟代碳酸乙烯酯或4-氟-5-甲基碳酸乙烯酯中的至少一种。
  3. 根据权利要求1所述的电化学装置，其特征在于，满足如下条件(a)至(d)中的至少一种：
    (a)所述电解液中还包括：二腈化合物；
    (b)所述电解液中还包括：氰基数量大于等于3的多腈化合物；
    (c)所述电解液中还包括：含S＝O双键的化合物；
    (d)所述电解液中还包括：含氧杂环化合物。
  4. 根据权利要求3所述电化学装置，
    所述二腈化合物占所述电解液总质量的C％，所述多腈化合物占所述电解液总质量的D％，0.5≤D/C≤20；
    和/或，所述式Ⅰ所示化合物与所述多腈化合物满足：0.02≤A/D≤130。
  5. 根据权利要求3所述电化学装置，其特征在于，
    所述二腈化合物包括：丁二腈、戊二腈、己二腈、庚二腈、辛二腈、壬二腈、癸二腈，乙二醇(双丙腈)醚(腈醚)或反丁烯二腈中的至少一种；
    和/或，
    所述多腈化合物包括：1,3,6-己烷三腈、1,2,6-己烷三腈、1,3,5-戊烷三腈、壬三腈、1,3,5-苯三腈、2,4,6-三氟苯-1,3,5-三腈、1,3,5-环己三腈、1,2,3-丙三甲腈、1,3,5-苯三氰基或1,2,3-三(2-氰氧基)丙烷中的至少一种。
  6. 根据权利要求3所述电化学装置，其特征在于，
    所述含S＝O双键的化合物包括：1,3-丙烷磺酸内酯、2,4-丁烷磺酸内酯、1,4-丁烷磺酸内酯、甲烷二磺酸亚甲酯、硫酸乙烯酯、环丁砜、硫酸丙烯酯、4-甲基硫酸亚乙酯或5-甲基恶噻戊环2,2-二氧化物中的至少一种；
    和/或，
    所述含氧杂环化合物包括：1,3-二氧杂环己烷、二氧戊环、4-甲基-1,3-二氧六环、四氢吡喃、四氢呋喃或1,2-环氧丁烷中的至少一种。
  7. 根据权利要求1所述电化学装置，其特征在于，所述正极集流体满足条件(e)至(j)中的至少一种：
    (e)所述正极集流体包含铝；
    (f)所述正极集流体厚度为5μm至20μm；
    (g)所述正极集流体包含M元素，所述M元素包括硅、铜、锰、铁、锌、镁、钛、钒中的至少一种，所述M元素占所述正极集流体总重量的百分比不大于2％；
    (h)所述正极集流体单位面积重量为15g/m 2至100g/m 2；
    (i)所述正极集流体的延伸率≥1％；
    (j)所述正极集流体上具有焊印区域，所述焊印区域的面积为F cm 2，1≤F≤50。
  8. 根据权利要求1所述电化学装置，其特征在于，所述负极包括负极集流体和负极活性物质层，所述负极活性物质层包括负极材料，所述负极材料包括硅基材料，所述硅基材料的颗粒表面的至少一部分区域上具有保护层。
  9. 根据权利要求8所述电化学装置，其特征在于，所述保护层包括：碳材料或Me xO y，其中，Me包括Al、Si、Mn、V、Cr、Co或Zr中的至少一种，x为1至2，y为1至3。
  10. 一种电子装置，其特征在于，包括如权利要求1至9中任一项所述的电化学装置。
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