WO2024130535A1 - 电化学装置及电子装置 - Google Patents

电化学装置及电子装置 Download PDF

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WO2024130535A1
WO2024130535A1 PCT/CN2022/140265 CN2022140265W WO2024130535A1 WO 2024130535 A1 WO2024130535 A1 WO 2024130535A1 CN 2022140265 W CN2022140265 W CN 2022140265W WO 2024130535 A1 WO2024130535 A1 WO 2024130535A1
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substituted
unsubstituted
compound
negative electrode
group
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French (fr)
Inventor
王翔
王蕊
唐超
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Dongguan Amperex Technology Ltd
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Dongguan Amperex Technology Ltd
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Priority to CN202280039803.0A priority Critical patent/CN117480655A/zh
Priority to PCT/CN2022/140265 priority patent/WO2024130535A1/zh
Priority to EP22968838.7A priority patent/EP4579848A4/en
Publication of WO2024130535A1 publication Critical patent/WO2024130535A1/zh
Priority to US19/006,878 priority patent/US20250201923A1/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0567—Liquid materials characterised by the additives
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0568—Liquid materials characterised by the solutes
    • H—ELECTRICITY
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    • 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
    • H01M4/134—Electrodes based on metals, Si or alloys
    • 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
    • H01M4/362—Composites
    • H01M4/366—Composites as layered products
    • 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
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/386—Silicon or alloys based on silicon
    • 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
    • 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
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
    • 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
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
    • 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
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • 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
    • H01M2004/027—Negative electrodes
    • H—ELECTRICITY
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    • 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
    • H01M2300/004—Three 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 battery technology, and more specifically, to electrochemical devices and electronic devices.
  • lithium-ion batteries As a portable electrochemical device, lithium-ion batteries have been widely used in electronic products such as mobile phones, laptops, and cameras in recent years.
  • silicon has a theoretical specific capacity that is much greater than that of graphite, which can reach 4200mAh/g, and the reserves of silicon in nature are very large. Therefore, many researchers believe that silicon-based materials are most likely to replace graphite and become the negative electrode material of the next generation of lithium-ion batteries to meet consumers' requirements for high battery life of electronic products.
  • silicon-based materials are very prone to volume expansion and contraction, which in turn leads to gaps between active materials, affecting the migration of electrons and lithium ions.
  • the volume expansion and contraction of silicon-based materials easily lead to the rupture of the solid electrolyte interface (SEI) film.
  • SEI solid electrolyte interface
  • repairing the SEI film will consume electrolyte and active lithium, resulting in the attenuation of cycle life.
  • the side reactions at the fresh interface generated by the rupture of the SEI film are intensified, resulting in a decrease in high-temperature storage safety. Therefore, the current cycle performance and high-temperature storage performance of lithium-ion batteries still need to be further improved.
  • the present application provides an electrochemical device and an electronic device, which can significantly improve the cycle performance and high-temperature storage performance of the electrochemical device.
  • the present application proposes an electrochemical device.
  • the electrochemical device comprises a negative electrode plate and an electrolyte;
  • the negative electrode plate comprises a negative electrode active material layer,
  • the negative electrode active material layer comprises a silicon-based material;
  • the electrolyte comprises a compound of formula (I),
  • X is selected from an oxygen atom or NR 8 ;
  • R 1 , R 2 , R 3 , R 4 , R 5 , R 6 and R 8 are each independently selected from a hydrogen atom, a halogen atom, a substituted or unsubstituted C 1 to C 10 alkyl group, a substituted or unsubstituted C 2 to C 10 alkenyl group, a substituted or unsubstituted C 2 to C 10 alkynyl group, a substituted or unsubstituted C 6 to C 10 aryl group, a substituted or unsubstituted C 1 to C 10 alkoxy group, a substituted or unsubstituted C 2 to C 10 alkenyloxy group, a substituted or unsubstituted C 2 to C 10 alkynyloxy group, a substituted or unsubstituted C 6 to C 10 aryloxy group, a substituted or unsubstituted C 1 to
  • the compound of formula (I) is added to the electrolyte.
  • the unsaturated double bonds therein can be polymerized to form a film on the surface of the silicon-based material, thereby introducing a rigid bridge ring structure in the SEI film and inhibiting the volume expansion of the silicon-based material; at the same time, due to the steric hindrance of the bridge ring structure in the compound of formula (I), a relatively small film formation impedance can be obtained, and the dense accumulation of by-products on the surface of the active material during the cycle process can be inhibited, thereby promoting the transmission of lithium ions between the active material and the electrolyte;
  • the compound of formula (I) can also form a film on the positive electrode, and the anhydride/amide structure therein can inhibit the damage of trace water and acid in the electrolyte to the electrolyte interface film on the surface of the positive electrode material, thereby inhibiting the oxidative decomposition of the solvent on the positive electrode surface, thereby improving the
  • the content of silicon in the negative electrode active material layer is Y mg/cm 2 ; based on the mass of the electrolyte, the mass percentage of the compound of formula (I) is a %; and 0.1 ⁇ a/Y ⁇ 20. In some embodiments, 0.3 ⁇ a/Y ⁇ 13.5.
  • the compound of formula (I) includes at least one of the compounds of formula (I-1) to formula (I-20):
  • the electrolyte further comprises a fluorinated carbonate compound, and the mass percentage of the fluorinated carbonate compound is b%, based on the mass of the electrolyte, 1 ⁇ b ⁇ 22. In some embodiments, 5 ⁇ b ⁇ 17.
  • the electrolyte further comprises a carboxylate solvent, and based on the mass of the electrolyte, the mass percentage of the carboxylate solvent is c%, satisfying: 0.1 ⁇ (b/c)/Y ⁇ 5.5. In some embodiments, 0.5 ⁇ (b/c)/Y ⁇ 3.
  • the fluorinated carbonate compound includes at least one of fluorinated ethylene carbonate, fluorinated propylene carbonate, fluorinated diethyl carbonate, difluoroethylene carbonate, bis(trifluoromethyl) carbonate, bis(pentafluoroethyl) carbonate, or bis(2,2,2-trifluoroethyl) carbonate.
  • the carboxylate solvent comprises a substituted or unsubstituted carboxylate having a total number of C atoms of 3 to 10 in the molecule; when substituted, the substituent comprises a halogen atom.
  • the carboxylate solvent includes one or more of methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate, ethyl fluoroacetate, propyl fluoroacetate, butyl fluoroacetate, ethyl fluoropropionate, propyl fluoropropionate and butyl fluoropropionate.
  • the electrolyte further includes an unsaturated cyclic carbonate compound, and the unsaturated cyclic carbonate compound includes at least one of vinylene carbonate or vinyl ethylene carbonate; based on the mass of the electrolyte, the mass percentage of the unsaturated cyclic carbonate compound is 0.01% to 5%.
  • the electrolyte further includes a cyclic sulfonate compound
  • the cyclic sulfonate compound includes at least one of 1,3-propylene sultone, 1,3-propane sultone or 1,4-butane sultone; based on the mass of the electrolyte, the mass percentage of the cyclic sulfonate compound is 0.01% to 5%.
  • the electrolyte further includes an unsaturated nitrile compound, and the unsaturated nitrile compound includes at least one of 3-hexenediconylate or butenediconylate; based on the mass of the electrolyte, the mass percentage of the unsaturated nitrile compound is 0.01% to 5%.
  • the electrolyte further includes an unsaturated acid anhydride compound
  • the unsaturated acid anhydride compound includes at least one of maleic anhydride, 2,3-dimethylmaleic anhydride, itaconic anhydride or citraconic anhydride; based on the mass of the electrolyte, the mass percentage of the unsaturated acid anhydride compound is 0.01% to 5%.
  • the electrolyte further includes unsaturated silane compounds, and the unsaturated silane compounds include at least one of triallylmethoxysilane, allyltrimethoxysilane, allyloxytrimethylsilane or propynyloxytrimethylsilane; based on the mass of the electrolyte, the mass percentage of the unsaturated silane compounds is 0.01% to 5%.
  • the silicon-based material includes a substrate and a protective layer located on the surface of the substrate, the protective layer includes an M element, and the M element includes at least one of C, Ti, Al, Zn, S, P, B or N.
  • the matrix includes at least one of a silicon-oxygen composite material, a silicon-carbon composite material, or silicon alone.
  • the content of the M element in the protective layer is 150 ppm to 6500 ppm. In some embodiments, based on the mass of the protective layer, the content of the M element in the protective layer is 150 ppm to 4000 ppm.
  • the negative electrode active material layer further includes a carbon material; based on the total mass of the carbon material and the silicon-based material, the mass percentage of the silicon-based material is 2% to 80%.
  • the porosity of the negative electrode active material layer is P, and 20% ⁇ P ⁇ 40%.
  • the present application proposes an electronic device, comprising an electrochemical device as in any embodiment of the first aspect of the present application.
  • a compound of formula (I) is added to the electrolyte.
  • the unsaturated double bonds therein can be polymerized to form a film on the surface of the silicon-based material, thereby introducing a rigid bridge ring structure in the SEI film and inhibiting the volume expansion of the silicon-based material; at the same time, due to the steric hindrance of the bridge ring structure in the compound of formula (I), a relatively small film formation impedance can be obtained, and the dense accumulation of by-products on the surface of the active material during the cycle can be inhibited, thereby promoting the transmission of lithium ions between the active material and the electrolyte;
  • the compound of formula (I) can also form a film on the positive electrode, and the anhydride/amide structure therein can inhibit the damage of the trace water and acid in the electrolyte to the electrolyte interface film on the surface of the positive electrode material, thereby inhibiting the oxidative de
  • a list of items connected by the terms “one or more of,” “one or more of,” “one or more of,” or other similar terms may mean any combination of the listed items.
  • the phrase “at least one of A and B” means only A; only B; or A and B.
  • the phrase “at least one of A, B, and C” means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B, and C.
  • Item A may include a single element or multiple elements.
  • Item B may include a single element or multiple elements.
  • Item C may include a single element or multiple elements.
  • halogen atom means a fluorine atom, a chlorine atom, a bromine atom, an iodine atom or the like.
  • nitrogen-containing group refers to a group containing a nitrogen atom, including an amine group, an amide group, and the like.
  • sulfur-containing group refers to a group containing a sulfur atom in the group, including alkylthio, sulfonate, sulfate, sulfone, and the like.
  • boron-containing group refers to a group containing a boron atom in the group, including borate ester groups and the like.
  • silicon-containing group refers to a group containing a silicon atom in the group, including a silane group, a silicate group, and the like.
  • phosphorus-containing group refers to a group containing a phosphorus atom in the group, including phosphate group, phosphite group, etc.
  • the present application provides an electrochemical device, the electrochemical device comprising a negative electrode plate and an electrolyte; the negative electrode plate comprises a negative electrode active material layer, the negative electrode active material layer comprises a silicon-based material.
  • the electrolyte comprises a compound of formula (I),
  • X is selected from an oxygen atom or NR 8 ;
  • R 1 , R 2 , R 3 , R 4 , R 5 , R 6 and R 8 are each independently selected from a hydrogen atom, a halogen atom, a substituted or unsubstituted C 1 to C 10 alkyl group, a substituted or unsubstituted C 2 to C 10 alkenyl group, a substituted or unsubstituted C 2 to C 10 alkynyl group, a substituted or unsubstituted C 6 to C 10 aryl group, a substituted or unsubstituted C 1 to C 10 alkoxy group, a substituted or unsubstituted C 2 to C 10 alkenyloxy group, a substituted or unsubstituted C 2 to C 10 alkynyloxy group, a substituted or unsubstituted C 6 to C 10 aryloxy group, a substituted or unsubstituted C 1 to
  • the compound of formula (I) is added to the electrolyte.
  • the unsaturated double bonds therein can be polymerized to form a film on the surface of the silicon-based material, thereby introducing a rigid bridge ring structure in the SEI film and inhibiting the volume expansion of the silicon-based material; at the same time, due to the steric hindrance of the bridge ring structure in the compound of formula (I), a relatively small film formation impedance can be obtained, and the dense accumulation of by-products on the surface of the active material during the cycle process can be inhibited, thereby promoting the transmission of lithium ions between the active material and the electrolyte;
  • the compound of formula (I) can also form a film on the positive electrode, and the anhydride/amide structure therein can inhibit the damage of trace water and acid in the electrolyte to the electrolyte interface film on the surface of the positive electrode material, thereby inhibiting the oxidative decomposition of the solvent on the positive electrode surface, thereby improving the
  • the content of silicon in the negative electrode active material layer is Y mg/cm 2 ; based on the mass of the electrolyte, the mass percentage of the compound of formula (I) is a %; and 0.1 ⁇ a/Y ⁇ 20 is satisfied.
  • the present application regulates the electrochemical device to continue to satisfy a/Y ⁇ 20, which can improve the cycle performance of the electrochemical device.
  • a/Y can be 0.1, 0.2, 0.5, 0.8, 1.0, 1.5, 2, 5, 6, 7, 8, 9, 10, 11, 12, 13, 15, 17, 19, 20, or a range consisting of any two of the above values.
  • the film-forming impedance is large, which is not conducive to the insertion and extraction of lithium ions; when the content of the compound of formula (I) is too small, it is not conducive to the formation of a dense and uniform SEI film on the surface of the active material, and it is not possible to provide good protection for the active material; therefore, the present application further regulates 0.01 ⁇ a ⁇ 10, which can form a dense and uniform SEI film, can better repair the SEI film, and the formed film layer impedance is relatively low, which is conducive to improving the kinetic performance of the electrochemical device.
  • the content a% of the compound of formula (I) can be 0.01%, 0.02%, 0.05%, 0.08%, 0.1%, 0.2%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.5%, 2.8%, 3%, 3.5%, 3.8%, 4%, 4.5%, 5%, 7%, 8%, 10% or a range consisting of any two of the above values.
  • the negative electrode current collector has two surfaces opposite to each other along its own thickness direction, and the negative electrode active material layer can be arranged on one surface of the negative electrode current collector, or on both surfaces of the negative electrode current collector.
  • Y represents the mass of silicon element per unit coating area of the negative electrode active material layer on a single surface of the negative electrode current collector. Since silicon-based materials have a large volume change during the charge and discharge process, this application further regulates the content of silicon element to meet 0.1 ⁇ Y ⁇ 1.55, which can ensure the high energy density of the electrochemical device and significantly alleviate the volume change problem of silicon-based materials, which is conducive to improving the structural stability of the negative electrode plate, thereby improving the cycle performance and high temperature storage performance of the electrochemical device.
  • the mass of silicon element per unit coating area of the negative electrode active material layer on the negative electrode current collector may be 0.1 mg/cm 2 , 0.2 mg/cm 2 , 0.5 mg/cm 2 , 0.8 mg/cm 2 , 0.9 mg/cm 2 , 1.0 mg/cm 2 , 1.1 mg/cm 2 , 1.2 mg/cm 2 , 1.3 mg/cm 2 , 1.4 mg/cm 2 , 1.5 mg/cm 2 , 1.55 mg/cm 2 or a range consisting of any two of the above values.
  • the compound of formula (I) includes at least one of the compounds of formula (I-1) to formula (I-20):
  • the unsaturated double bonds in the molecules of the above-mentioned compounds can be polymerized into films on the surface of silicon-based materials.
  • the electrolyte further comprises a fluorocarbonate compound, and the mass percentage of the fluorocarbonate compound is b%, based on the mass of the electrolyte, and 1 ⁇ b ⁇ 22.
  • Fluorinated carbonate compounds have fluorine-substituted groups, which have strong electron-withdrawing ability and are easily reductively decomposed at higher potentials, promoting the formation and repair of SEI films; and the formed SEI film has a small impedance, which is conducive to the migration of lithium ions, etc., thereby improving the cycle performance of the electrochemical device.
  • the HF generated by the decomposition of fluorocarbonate compounds at high temperatures can be captured by the anhydride/amide structure in the compound of formula (I), inhibiting its damage to the positive electrode electrolyte interface film, thereby ensuring the high temperature storage performance of the electrochemical device.
  • the mass percentage b% of the fluorocarbonate compound relative to the total mass of the electrolyte can be 1%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 12%, 13%, 14%, 15%, 16%, 17%, 20%, 22% or a range consisting of any two of the above values.
  • the fluorinated carbonate compound includes at least one of fluorinated ethylene carbonate, fluorinated propylene carbonate, fluorinated diethyl carbonate, difluoroethylene carbonate, bis(trifluoromethyl) carbonate, bis(pentafluoroethyl) carbonate, or bis(2,2,2-trifluoroethyl) carbonate.
  • the electrolyte further includes a carboxylate solvent, and based on the mass of the electrolyte, the mass percentage of the carboxylate solvent is c%, satisfying: 0.1 ⁇ (b/c)/Y ⁇ 5.5.
  • the electrolyte contains a carboxylate solvent, its ion conductivity is greatly improved, which can reduce the impedance of the electrochemical device and improve the cycle performance of the electrochemical device.
  • the carboxylate solvent is unstable on the surface of the silicon-based material and is easily decomposed and gasified at the negative electrode, while the fluorocarbonate compound can undergo reduction decomposition at a higher potential and decompose into a film on the surface of the silicon-based material before the carboxylate solvent, thereby effectively alleviating the reduction decomposition of the carboxylate solvent.
  • the HF generated by the decomposition of the fluorocarbonate compound at high temperature can be captured by the anhydride/amide structure in the compound of formula (I), inhibiting its damage to the positive electrode electrolyte interface film, thereby ensuring the high temperature storage performance of the electrochemical device.
  • the present application regulates 0.1 ⁇ (b/c)/Y ⁇ 5.5, so that the carboxylic acid ester solvent, the fluorocarbonate compound and the compound of formula (I) can work synergistically, while ensuring the high temperature storage performance of the electrochemical device, and simultaneously improve the impedance of the electrochemical device and the repair ability of the electrolyte to the SEI film, which is beneficial to improving the cycle performance and kinetic performance of the electrochemical device.
  • (b/c)/Y can be 0.1, 0.2, 0.4, 0.5, 0.8, 1.0, 1.2, 1.5, 1.8, 2, 2.5, 2.8, 3, 3.5, 4, 5, 5.5 or a range consisting of any two of the above values.
  • the mass percentage c% of the carboxylate solvent can be 5%, 8%, 10%, 15%, 20%, 30%, 35%, 40%, 45%, 50%, 60%, 70% or a range consisting of any two of the above values.
  • Carboxylate solvents have relatively low viscosity. When the mass percentage of the carboxylate solvent is in the above range, it can improve the ionic conductivity of the electrolyte, so that the electrochemical device can achieve a higher charge and discharge rate.
  • the carboxylate solvent includes a substituted or unsubstituted carboxylate having a total of 3 to 10 C atoms in the molecule; when substituted, the substituent includes a halogen atom.
  • the carboxylate solvent includes at least one of methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate, ethyl fluoroacetate, propyl fluoroacetate, butyl fluoroacetate, ethyl fluoropropionate, propyl fluoropropionate or butyl fluoropropionate.
  • the electrolyte further includes an unsaturated cyclic carbonate compound, and the unsaturated cyclic carbonate compound includes at least one of vinylene carbonate or vinyl ethylene carbonate; based on the mass of the electrolyte, the mass percentage of the unsaturated cyclic carbonate compound is 0.01% to 5%.
  • the electrolyte further includes a cyclic sulfonate compound, wherein the cyclic sulfonate compound includes at least one of 1,3-propylene sultone, 1,3-propane sultone or 1,4-butane sultone; based on the mass of the electrolyte, the mass percentage of the cyclic sulfonate compound is 0.01% to 5%.
  • the electrolyte further includes an unsaturated nitrile compound, wherein the unsaturated nitrile compound includes at least one of 3-hexenediconylate or butenediconylate; based on the mass of the electrolyte, the mass percentage of the unsaturated nitrile compound is 0.01% to 5%.
  • the electrolyte further includes an unsaturated acid anhydride compound, wherein the unsaturated acid anhydride compound includes at least one of maleic anhydride, 2,3-dimethylmaleic anhydride, itaconic anhydride or citraconic anhydride; based on the mass of the electrolyte, the mass percentage of the unsaturated acid anhydride compound is 0.01% to 5%.
  • the electrolyte further includes unsaturated silane compounds, and the unsaturated silane compounds include at least one of triallylmethoxysilane, allyltrimethoxysilane, allyloxytrimethylsilane or propynyloxytrimethylsilane; based on the mass of the electrolyte, the mass percentage of the unsaturated silane compounds is 0.01% to 5%.
  • the above compound Since the above compound has double bonds, it can undergo a cross-linking reaction with the compound of formula (I) during the charge and discharge process of the electrochemical device, thereby promoting the uniform formation of the SEI film and further improving the cycle performance and high-temperature storage performance of the electrochemical device.
  • the electrolyte further includes other organic solvents, such as one or more of carbonate solvents and ether solvents.
  • the organic solvent may also include one or more of ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate, ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate (DEC), dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, ethylene glycol dimethyl ether (DME), tetrahydrofuran (THF), and dioxolane (DOL).
  • EC ethylene carbonate
  • PC propylene carbonate
  • DEC butylene carbonate
  • ethyl methyl carbonate dimethyl carbonate
  • DEC diethyl carbonate
  • DME dipropyl carbonate
  • methyl propyl carbonate ethyl propyl carbonate
  • DME ethylene glycol dimethyl ether
  • THF tetrahydrofuran
  • DOL di
  • the electrolyte of the present application also contains an electrolyte salt.
  • the electrolyte salt is an electrolyte salt suitable for electrochemical devices known in the art.
  • a suitable electrolyte salt can be selected.
  • the electrolyte salt is usually a lithium salt.
  • the lithium salt includes at least one of an organic lithium salt and an inorganic lithium salt.
  • the lithium salt may include lithium hexafluorophosphate LiPF 6 .
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector, wherein the negative electrode active material layer contains a negative electrode active material.
  • the structure of the negative electrode sheet is a structure of a negative electrode sheet that is well known in the art and can be used in an electrochemical device.
  • the negative electrode current collector is a metal, such as but not limited to copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, or a combination thereof.
  • the negative electrode active material may be any of various substances known in the art that can be used as negative electrode active materials for electrochemical devices and can reversibly intercalate and deintercalate active ions.
  • the negative electrode active material comprises a silicon-based material.
  • the silicon-based material includes a substrate and a protective layer located on the surface of the substrate, the protective layer includes M elements, and the M elements include at least one of carbon C elements, titanium Ti elements, aluminum Al elements, zinc Zn elements, sulfur S elements, phosphorus P elements, boron B elements, or nitrogen N elements.
  • the substrate can be nanoparticles, and nano-scale particles can significantly improve the problem of volume change of silicon-based materials, reduce the amount of volume change, thereby improving the overall structural stability of the negative electrode active material layer, and improving the cycle performance of the electrochemical device.
  • the protective layer is coated on the surface of the substrate, which can further alleviate the volume change of the substrate, and the metal ions, carbon, etc.
  • the protective layer can improve the conductivity of the silicon-based material, which is beneficial to improve the cycle performance and high-temperature storage performance of the electrochemical device; in addition, the protective layer can reduce the generation of byproducts on the surface of the silicon-based material during the cycle, which is beneficial to further improve the cycle performance of the electrochemical device.
  • the material of the protective layer includes carbon, aluminum oxide Al 2 O 3 , titanium oxide TiO 2 , and zinc oxide ZnO.
  • the matrix includes at least one of a silicon-oxygen composite material, a silicon-carbon composite material, or a silicon element.
  • the general formula of the silicon-oxygen composite material is SiOx, 0.5 ⁇ x ⁇ 1.5.
  • Oxygen may be present in the silicon-carbon composite material; the ratio of the mass content of silicon, the mass content of carbon, and the mass content of oxygen in the silicon-carbon composite material is (1 to 6): (1 to 3): (1 to 0).
  • the content of the M element in the protective layer is 150ppm to 6500ppm.
  • the protective layer can effectively alleviate the volume change of the substrate and is conducive to the capacity of the substrate.
  • the content of the M element in the protective layer can be 150ppm, 200ppm, 500ppm, 800ppm, 1000ppm, 1500ppm, 2000ppm, 2500ppm, 3000ppm, 3500ppm, 4000ppm, 4500ppm, 5000ppm, 5500ppm, 6000ppm, 6500ppm or a range consisting of any two of the above values.
  • the negative electrode active material may also include at least one of lithium metal, lithium metal alloy, carbon material or transition metal oxide.
  • the negative electrode active material also includes a carbon material.
  • the carbon material can be selected from various carbon materials known in the art that can be used as carbon-based negative electrode active materials for electrochemical devices. Based on the total mass of the carbon material and the silicon-based material, the mass percentage of the carbon material is 2% to 80%. Exemplarily, the mass percentage of the carbon material is 2%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80% or a range composed of any two of the above values. The mixed use of carbon materials and silicon-based materials can improve the cycle performance of electrochemical devices.
  • the carbon material includes at least one of natural graphite, artificial graphite, crystalline graphite, soft carbon, hard carbon, pyrolytic carbon, mesophase pitch-based carbon fiber, mesophase carbon microbeads, mesophase pitch, and high-temperature calcined carbon.
  • the negative electrode active material layer may further include a negative electrode binder, and the ratio of the mass of the negative electrode active material to the mass of the negative electrode binder is (80 to 100): (0.5 to 10).
  • the negative electrode sheet that meets the above mass ratio has better comprehensive performance, which can not only make the negative electrode active material layer have good adhesion, but also ensure that the electrochemical device has a higher energy density.
  • the negative electrode binder includes at least one of difluoroethylene-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinylidene fluoride, polyacrylonitrile, acrylate polymer, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, and nylon.
  • PVDF-co-HFP difluoroethylene-hexafluoropropylene copolymer
  • PVDF-co-HFP difluoroethylene-hexafluoropropylene copolymer
  • PVDF-co-HFP difluoroethylene-hexafluoropropylene copolymer
  • PVDF-co-HFP diflu
  • the negative electrode active material layer may further include a negative electrode conductive agent.
  • the negative electrode conductive agent is used to provide conductivity to the electrode, and it may include any conductive material as long as it does not cause chemical changes.
  • the negative electrode conductive agent includes any one of a carbon-based material, a metal-based material, and a conductive polymer, or a mixture thereof.
  • the carbon-based material includes at least one of carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanotube, and graphene.
  • the metal-based material includes at least one of metal powders or metal fibers of copper, nickel, aluminum, silver, etc.
  • the conductive polymer includes a polyphenylene derivative.
  • the method for preparing the negative electrode sheet is a method for preparing the negative electrode sheet that can be used for an electrochemical device that is well known in the art.
  • a negative electrode active material and a negative electrode binder are usually added, and a negative electrode conductive agent and a thickener are added as needed and then dissolved or dispersed in a solvent to form a negative electrode slurry.
  • the solvent is evaporated and removed during the drying process.
  • the solvent is a solvent that is well known in the art and can be used as a negative electrode active material layer, and the solvent is, for example, but not limited to, water.
  • the thickener is a thickener that is well known in the art and can be used as a negative electrode active material layer, and the thickener is, for example, but not limited to, sodium carboxymethyl cellulose.
  • the present application has no particular limitation on the mixing ratio of the negative electrode active material, the negative electrode binder, and the thickener in the negative electrode active material layer, and the mixing ratio can be controlled according to the desired performance of the electrochemical device.
  • the porosity of the negative electrode active material layer is P, 10% ⁇ P ⁇ 50%.
  • the electrolyte can fully infiltrate the negative electrode active material layer, which can effectively shorten the transmission distance of lithium ions and improve the kinetic performance of the electrochemical device; and the particles in the negative electrode active material layer are in close contact, and the effective contact between the particles can be maintained during the charge and discharge process, thereby ensuring the cycle performance of the electrochemical device.
  • the porosity P of the negative electrode active material layer can be 10%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, 40%, 50% or a range consisting of any two of the above values. In some embodiments, 20% ⁇ P ⁇ 40%.
  • the positive electrode sheet is a positive electrode sheet known in the art that can be used in an electrochemical device.
  • the positive electrode sheet includes a positive current collector and a positive active material layer.
  • the positive active material layer is disposed on the surface of the positive current collector.
  • the positive active material layer includes a positive active material.
  • the structure of the positive electrode sheet is a structure of a positive electrode sheet that is well known in the art and can be used in an electrochemical device.
  • the positive electrode current collector is a metal, such as but not limited to aluminum foil.
  • the positive electrode active material can be selected from various substances known in the art that can be used as positive electrode active materials for electrochemical devices and can reversibly intercalate and deintercalate active ions.
  • the positive electrode active material generally contains lithium ions.
  • the positive electrode active material comprises a positive electrode material capable of absorbing and releasing lithium, including but not limited to lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium manganese oxide, lithium manganese iron phosphate, lithium iron phosphate, and lithium-rich manganese-based materials.
  • the positive electrode active material layer further comprises a positive electrode binder and a positive electrode conductor.
  • the positive electrode binder is used to improve the bonding performance between the positive electrode active material particles and the positive electrode active material particles and the current collector.
  • the positive electrode binder includes polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, styrene-butadiene rubber, acrylic (ester) styrene-butadiene rubber, epoxy resin, nylon at least one.
  • the positive electrode conductor is used to provide conductivity for the electrode, which may include any conductive material as long as it does not cause chemical changes.
  • the positive electrode conductor includes at least one of carbon black, acetylene black, ketjen black, carbon fiber, carbon nanotubes, graphene, metal powder, metal fiber, and polyphenylene derivatives.
  • the metal in the metal powder and metal fiber includes at least one of copper, nickel, aluminum, and silver.
  • the method for preparing the positive electrode sheet is a method for preparing the positive electrode sheet that can be used for an electrochemical device that is well known in the art.
  • the positive electrode active material, the positive electrode binder and the positive electrode conductive agent are usually added and dissolved or dispersed in a solvent to form a positive electrode slurry.
  • the solvent is evaporated and removed during the drying process.
  • the solvent is a solvent that is well known in the art and can be used as a positive electrode active material layer, and the solvent is, for example, but not limited to, N-methylpyrrolidone (NMP).
  • the separator is a separator known in the art that can be used in electrochemical devices, such as but not limited to a polyolefin microporous membrane.
  • the separator comprises at least one of polyethylene (PE), ethylene-propylene copolymer, polypropylene (PP), ethylene-butene copolymer, ethylene-hexene copolymer, and ethylene-methyl methacrylate copolymer.
  • the isolation film is a single-layer isolation film or a multi-layer isolation film.
  • the isolation film is coated with a coating.
  • the coating comprises at least one of an organic coating and an inorganic coating, wherein the organic coating comprises at least one of polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polyacrylonitrile, polyimide, acrylonitrile-butadiene copolymer, acrylonitrile-styrene-butadiene copolymer, acrylate polymer, acrylic acid-styrene copolymer, polydimethylsiloxane, sodium polyacrylate, and sodium carboxymethylcellulose, and the inorganic coating comprises inorganic particles and a binder, and the inorganic particles comprise at least one of SiO 2 , Al 2 O 3 , CaO, TiO 2 , ZnO 2 , MgO, ZrO 2 , and SnO 2 .
  • the present application has no particular limitation on the shape and thickness of the separator.
  • the method for preparing the separator is a method known in the art that can be used for a separator of an electrochemical device.
  • the present application also provides an electronic device, comprising the electrochemical device described above in the present application.
  • the electronic device of the present application is any electronic device, such as but not limited to a laptop computer, a pen-input computer, a mobile computer, an e-book player, a portable phone, a portable fax machine, a portable copier, a portable printer, a head-mounted stereo headset, a video recorder, an LCD television, a portable cleaner, a portable CD player, a mini CD, a transceiver, an electronic notepad, a calculator, a memory card, a portable recorder, a radio, a backup power supply, a motor, a car, a motorcycle, a power-assisted bicycle, a bicycle, a lighting fixture, a toy, a game console, a clock, an electric tool, a flashlight, a camera, a large household battery, and a lithium-ion capacitor.
  • a laptop computer such as but not limited to a laptop computer, a pen-input computer, a mobile computer, an e-book player, a portable phone, a portable
  • the positive electrode active material lithium cobalt oxide ( LiCoO2 ), the conductive agent Super P, and the binder polyvinylidene fluoride are mixed in a weight ratio of 97:1.5:1.5, N-methylpyrrolidone (NMP) is added, and the mixture is stirred evenly under the action of a vacuum mixer to obtain a positive electrode slurry, wherein the solid content of the positive electrode slurry is 72wt%; the positive electrode slurry is evenly coated on one side of the positive electrode collector aluminum foil, and dried at 85°C to obtain a positive electrode sheet coated with a positive electrode active material layer on one side, and the above steps are repeated on the other side of the positive electrode collector aluminum foil to obtain a positive electrode sheet coated with a positive electrode active material layer on both sides, and then after cold pressing, cutting, and slitting, it is dried under vacuum conditions of 85°C for 4h to obtain a positive electrode sheet.
  • NMP N-methylpyrrolidone
  • the negative electrode active material artificial graphite and silicon-oxygen SiO composite material coated with metal oxide Al 2 O 3 (the Al content of the coating layer is 184ppm)
  • conductive agent Super P sodium carboxymethyl cellulose (CMC), and styrene-butadiene rubber (SBR) are mixed according to a weight ratio of 96.2:1.5:0.5:1.8, deionized water is added, and the mixture is stirred evenly under the action of a vacuum mixer to obtain a negative electrode slurry, wherein the solid content of the negative electrode slurry is 54wt%.
  • the negative electrode slurry is evenly coated on one side of the negative electrode collector copper foil, and dried at 85°C to obtain a negative electrode sheet coated with a negative electrode active material layer on one side, and the above steps are repeated on the other side of the negative electrode collector copper foil to obtain a negative electrode sheet coated with a negative electrode active material layer on both sides, and then after cold pressing, cutting, and slitting, it is dried at 120°C under vacuum conditions for 12h to obtain a negative electrode sheet.
  • the content Y of silicon element per unit coating area of the negative electrode active material layer was adjusted to 2.0 mg/cm 2 .
  • ethylene carbonate (EC), propylene carbonate (PC), and diethyl carbonate (DEC) were mixed in a weight ratio of 1:2:7, and an additive compound of formula (I) was added, and its content was shown in Table 1; lithium salt LiPF 6 was added after sufficient stirring, and the electrolyte was obtained after uniform mixing. Wherein, based on the mass of the electrolyte, the mass concentration of LiPF 6 was 12.5%.
  • a polyethylene (PE) porous membrane with a thickness of 8 ⁇ m was selected as the isolation membrane.
  • the positive electrode sheet, the isolation film, and the negative electrode sheet are stacked in order, so that the isolation film is placed between the positive electrode sheet and the negative electrode sheet to play an isolating role, and then they are wound to obtain a bare battery cell; after welding the pole ears, the bare battery cell is placed in an outer packaging aluminum-plastic film, and the prepared electrolyte is injected into the dried bare battery cell. After vacuum packaging, standing, formation, shaping, capacity testing and other processes, a soft-pack lithium-ion battery is obtained.
  • Comparative Examples 1-1 to Comparative Examples 1-3 are different from Example 1-1 in that the presence or absence of additives and the types of additives are adjusted.
  • Examples 1-2 to 1-9 are different from Example 1-1 in that the types of the compounds of formula (I) are adjusted.
  • Examples 1-10 to 1-15 are different from Example 1-1 in that the content of the compound of formula (I) is adjusted by a%.
  • Embodiments 1-16 to 1-25 are different from Embodiment 1-1 in that at least one of the mass proportion of the silicon-based material in the negative electrode active material and the coating amount per unit area of the negative electrode active material layer is adjusted, thereby adjusting the Si element distribution.
  • Comparative Example 2-1 is different from Example 1-1 in that the compound of formula (I) is not added in Comparative Example 2-1, and only FEC and carboxylic acid ester solvents are added.
  • Embodiments 2-1 to 2-7 are different from Embodiment 1-1 in that FEC is added in Embodiments 2-1 to 2-7.
  • Example 2-8 to Example 2-26 and Example 1-1 The difference between Example 2-8 to Example 2-26 and Example 1-1 is that FEC and carboxylic acid ester solvents are added in Example 2-8 to Example 2-26, and the type of the compound of formula (I) is adjusted.
  • Embodiments 3-1 to 3-8 are different from Embodiment 1-1 in that an additive containing a double bond is added, and the content of the compound of formula (I) and the type and content of the additive containing a double bond are adjusted.
  • Embodiments 4-1 to 4-8 are different from Embodiment 3-3 in that the presence or absence of a protective layer and the content of metal elements in the protective layer are adjusted.
  • Example 5-1 to 5-5 The difference between Examples 5-1 to 5-5 and Example 3-3 is that at least the porosity of the negative electrode active material layer is adjusted in Examples 5-1 to 5-5.
  • the lithium-ion battery was charged at 2C constant current to 4.45V at 35°C, then charged at constant voltage to a current of 0.05C, left to stand for 5 minutes, and then discharged at 0.5C to 3.0V.
  • This charge and discharge cycle was repeated 500 times; the first discharge capacity was recorded as C0, and the 500th cycle discharge capacity was recorded as C1;
  • Cycle capacity retention rate (%) C1/C0 ⁇ 100%.
  • the lithium-ion battery was charged to 4.45V at 2C constant current at room temperature, and then charged to 0.05C at constant voltage, and stored in a 70°C high temperature box for 7 days.
  • the thickness of the lithium-ion battery was tested with a micrometer when entering the furnace and leaving the furnace. The thickness entering the furnace was recorded as D0, and the thickness leaving the furnace was recorded as D1.
  • High temperature storage thickness growth rate (%) (D1/D0-1) ⁇ 100%.
  • the coating weight per unit area of the negative electrode active material layer refers to the coating weight of the negative electrode active material layer per unit area on the negative electrode current collector, and its unit is mg/cm 2 .
  • the Si element distribution Y refers to the content of silicon element per unit coating area of the negative electrode active material layer, and its unit is mg/cm 2 .
  • Table 1 shows the effects of the compound of formula (I) and the distribution of Si elements on the cycle and high-temperature storage performance of lithium-ion batteries. The results show that compared with vinylene carbonate VC and maleic anhydride, the compound of formula (I) can significantly improve the cycle performance and high-temperature storage performance of lithium-ion batteries.
  • the unsaturated double bond structure in its molecule can be polymerized on the surface of the silicon-based material to form a film, thereby introducing a rigid bridge ring structure into the SEI film and inhibiting the volume expansion of the silicon-based material; at the same time, due to the steric hindrance of the bridge ring structure in the compound of formula (I), a relatively small film formation impedance can be obtained, and the dense accumulation of byproducts on the surface of the active material during the cycle can be inhibited, promoting the transmission of lithium ions between the active material and the electrolyte; on the other hand, the compound of formula (I) can also form a film at the positive electrode, and the anhydride/amide structure therein can inhibit the damage of trace water and acid in the electrolyte to the electrolyte interface film on the surface of the positive electrode material, thereby inhibiting the oxidative decomposition of the solvent on the surface of the positive electrode material,
  • the cycle performance and high temperature storage performance of the lithium ion battery are both excellent.
  • the amount of additives required for SEI film formation and repair can be met, and the decrease in the cycle performance of the lithium ion battery due to excessive content of the compound of formula (I) can be avoided.
  • Table 2 shows the effects of FEC and carboxylic acid ester solvents on the cycle and high-temperature storage performance of lithium-ion batteries based on Example 1-1.
  • the results show that the addition of FEC can improve the long-cycle performance of lithium-ion batteries. This is because fluorocarbonate compounds have fluorine-substituted groups, which have strong electron-withdrawing ability and are prone to reduction decomposition at higher potentials, promoting the formation and repair of SEI films; and the formed SEI film has a small impedance, which is conducive to the migration of lithium ions, etc., thereby improving the cycle performance of lithium-ion batteries.
  • the HF generated by the decomposition of fluorocarbonate compounds at high temperatures can be captured by the anhydride/amide structure in the compound of formula (I), inhibiting its damage to the positive electrode electrolyte interface film, thereby ensuring the high-temperature storage performance of the electrochemical device.
  • the co-addition of FEC and carboxylic acid ester solvents can further improve the long-cycle performance of lithium-ion batteries.
  • carboxylic acid ester solvents are added to the electrolyte, its ion conductivity is greatly improved, which can reduce the impedance of lithium-ion batteries and improve the cycle performance of lithium-ion batteries.
  • carboxylic acid ester solvents are unstable on the surface of silicon-based materials and are easily decomposed and gasified at the negative electrode, while fluorocarbonate compounds can undergo reduction decomposition at a higher potential and decompose into a film on the surface of silicon-based materials before carboxylic acid ester solvents, thereby effectively alleviating the reduction decomposition of carboxylic acid ester solvents.
  • the HF generated by the decomposition of fluorocarbonate compounds at high temperature can be captured by the anhydride/amide structure in the compound of formula (I), inhibiting its damage to the positive electrode electrolyte interface film, thereby ensuring the high-temperature storage performance of the lithium-ion battery.
  • the cycle performance and high-temperature storage performance of the lithium-ion battery are both excellent.
  • Table 3 shows the effect of further adding other double bond-containing compounds on the cycle and high temperature storage performance of lithium-ion batteries based on Example 1-1.
  • the results show that when containing the compound of formula (I), further adding other double bond-containing additives can greatly improve the cycle and high temperature storage performance of lithium-ion batteries. This is because the above-mentioned additives containing double bonds can undergo cross-linking reactions with the compound of formula (I) during charging and discharging, promote the uniform formation of the SEI film, and further improve the cycle performance and high temperature storage performance of lithium-ion batteries.
  • Table 4 shows the effect of coating the protective layer on the surface of the silicon-containing substrate material on the cycle and high-temperature storage performance of the battery based on Example 3-3.
  • the results show that by providing a protective layer (metal oxide) on the surface of the silicon-containing substrate material, the cycle and high-temperature storage performance of the battery can be improved, mainly because the protective layer can alleviate the volume expansion of the silicon-containing material during the charging and discharging process, and the metal ions in the protective layer can improve the conductivity of the silicon-based material, thereby improving the cycle and high-temperature storage performance of the battery.
  • a protective layer metal oxide
  • Table 5 shows the effect of changing the porosity of the negative electrode active material layer on the cycle and high temperature storage performance of the battery based on Example 3-3. The results show that when the porosity of the negative electrode active material layer is 20% to 40%, excellent cycle and high temperature storage performance can be guaranteed.

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Abstract

本申请涉及一种电化学装置及电子装置，所述电化学装置包括负极极片和电解液；负极极片包括负极活性物质层，所述负极活性物质层包括硅基材料；所述电解液包括式(I)化合物，式(I)中，X选自氧原子或N-R 8。本申请的电化学装置能够具有显著改善的循环性能和高温存储性能。

Description

电化学装置及电子装置 技术领域
本申请涉及电池技术领域，更具体地，涉及电化学装置及电子装置。
背景技术
锂离子电池作为一种便携的电化学装置，近年来被广泛应用于手机、笔记本电脑、相机等电子产品中。随着消费者对电子产品续航的要求越来越高，硅由于其理论比容量远大于石墨的理论比容量，可达到4200mAh/g，且硅在自然界中的储量非常大，所以，众多研究者认为硅基材料最有希望取代石墨，成为下一代锂离子电池负极材料，满足消费者对电子产品高续航的要求。但是，在锂离子电池的充放电过程中，硅基材料非常容易发生体积膨胀和收缩，进而导致活性材料间产生间隙，影响电子和锂离子的迁移，同时，硅基材料的体积膨胀和收缩容易导致固体电解质界面(SEI)膜发生破裂，一方面，修复SEI膜将消耗电解液和活性锂，造成循环寿命的衰减，另一方面，在高温存储条件下，SEI膜破裂所产生的新鲜界面处的副反应加剧，造成高温存储安全性的降低。因此，目前锂离子电池的循环性能以及高温存储性能仍需进一步提升。
发明内容
本申请提供一种电化学装置及电子装置，能够显著改善电化学装置的循环性能和高温存储性能。
第一方面，本申请提出了一种电化学装置。所述电化学装置包括负极极片和电解液；所述负极极片包括负极活性物质层，所述负极活性物质层包括硅基材料；所述电解液包括式(I)化合物，
Figure PCTCN2022140265-appb-000001
式(I)中，X选自氧原子或N-R 8；R 1、R 2、R 3、R 4、R 5、R 6和R 8各自独立地选自氢原子、卤素原子、经取代或未经取代的C 1至C 10烷基、经取代或未经取代的C 2至C 10烯基、经取代或未经取代的C 2至C 10炔基、经取代或未经取代的C 6至C 10芳基、经取代或未经取代的C 1至C 10烷氧基、经取代或未经取代 的C 2至C 10烯氧基、经取代或未经取代的C 2至C 10炔氧基、经取代或未经取代的C 6至C 10芳氧基、经取代或未经取代的C 1至C 10烷氧基烷基、经取代或未经取代的C 1至C 10羧基、经取代或未经取代的C 2至C 10羧酸酯基、经取代或未经取代的C 2至C 10碳酸酯基、氰基、氨基、经取代或未经取代的C 1至C 10含氮基团、经取代或未经取代的C 1至C 10含硫基团、经取代或未经取代的C 1至C 10含硼基团、经取代或未经取代的C 1至C 10含硅基团或经取代或未经取代的C 1至C 10含磷基团；R 7选自经取代或未经取代的C 1至C 10亚烷基、经取代或未经取代的C 3至C 10亚环烷基、经取代或未经取代的C 1至C 10含氧基团或经取代或未经取代的C 1至C 10含氮基团；当经取代时，取代基包括卤素原子或氰基中的至少一种。
电解液中添加有式(I)化合物，一方面，其中的不饱和双键，能够在硅基材料表面聚合成膜，从而在SEI膜中引入刚性的桥环结构，抑制硅基材料的体积膨胀；同时，由于式(I)化合物中桥环结构的位阻，可以获得相对较小的成膜阻抗，并且可以抑制循环过程中的副产物在活性材料表面的密堆积，促进锂离子在活性材料和电解液之间的传输；另一方面，式(I)化合物也能够在正极成膜，其中的酸酐/酰胺结构可以抑制电解液中的微量水和酸对正极材料表面电解质界面膜的破坏，从而抑制溶剂在正极表面的氧化分解，进而提升电化学装置的循环性能和高温存储性能。
在一些实施例中，基于所述负极活性物质层的面积，所述负极活性物质层中硅元素的含量为Y mg/cm 2；基于所述电解液的质量，所述式(I)化合物的质量百分含量为a％；满足：0.1≤a/Y≤20。在一些实施例中，0.3≤a/Y≤13.5。
在一些实施例中，0.01≤a≤10。在一些实施例中，0.1≤a≤5。
在一些实施例中，0.1≤Y≤1.55。在一些实施例中，0.1≤Y≤1.2。
在一些实施例中，式(I)化合物包括式(I-1)化合物至式(I-20)化合物中的至少一种：
Figure PCTCN2022140265-appb-000002
Figure PCTCN2022140265-appb-000003
在一些实施例中，所述电解液还包括氟代碳酸酯类化合物，基于所述电解液的质量，所述氟代碳酸酯类化合物的质量百分含量为b％，1≤b≤22。在一些实施例中，5≤b≤17。
在一些实施例中，所述电解液还包括羧酸酯类溶剂，基于所述电解液的质量，所述羧酸酯类溶剂的质量百分含量为c％，满足：0.1≤(b/c)/Y≤5.5。在一些实施例中，0.5≤(b/c)/Y≤3。
在一些实施例中，5≤c≤70。在一些实施例中，5≤c≤60。
在一些实施例中，所述氟代碳酸酯类化合物包括氟代碳酸乙烯酯、氟代碳酸丙烯酯、氟代碳酸二乙酯、二氟代碳酸乙烯酯、二(三氟甲基)碳酸酯、碳酸二(五氟乙基)碳酸酯或二(2,2,2三氟乙基)碳酸酯中的至少一种。
在一些实施例中，所述羧酸酯类溶剂包括经取代或未经取代的分子中C原 子总数为3至10的羧酸酯；当经取代时，取代基包括卤素原子。
在一些实施例中，所述羧酸酯类溶剂包括乙酸甲酯、乙酸乙酯、乙酸丙酯、乙酸丁酯、丙酸甲酯、丙酸乙酯、丙酸丙酯、丙酸丁酯、氟代乙酸乙酯、氟代乙酸丙酯、氟代乙酸丁酯、氟代丙酸乙酯、氟代丙酸丙酯和氟代丙酸丁酯中的一种或多种。
在一些实施例中，所述电解液还包括不饱和环状碳酸酯类化合物，所述不饱和环状碳酸酯类化合物包括碳酸亚乙烯酯或碳酸乙烯亚乙酯中的至少一种；基于所述电解液的质量，所述不饱和环状碳酸酯类化合物的质量百分含量为0.01％至5％。
在一些实施例中，所述电解液还包括环状磺酸酯类化合物，所述环状磺酸酯类化合物包括1，3-丙烯磺酸内酯、1，3-丙烷磺酸内酯或1,4-丁磺酸内酯中的至少一种；基于所述电解液的质量，所述环状磺酸酯类化合物的质量百分含量为0.01％至5％。
在一些实施例中，所述电解液还包括不饱和腈类化合物，所述不饱和腈类化合物包括3-己烯二氰或丁烯二腈中的至少一种；基于所述电解液的质量，所述不饱和腈类化合物的质量百分含量为0.01％至5％。
在一些实施例中，所述电解液还包括不饱和酸酐类化合物，所述不饱和酸酐类化合物包括马来酸酐、2,3-二甲基马来酸酐、衣康酸酐或柠康酸酐中的至少一种；基于所述电解液的质量，所述不饱和酸酐类化合物的质量百分含量为0.01％至5％。
在一些实施例中，所述电解液还包括不饱和硅烷类化合物，所述不饱和硅烷类化合物包括三烯丙基甲氧基硅烷、烯丙基三甲氧基硅烷、烯丙氧基三甲基硅烷或丙炔氧基三甲基硅烷中的至少一种；基于所述电解液的质量，所述不饱和硅烷类化合物的质量百分含量为0.01％至5％。
在一些实施例中，所述硅基材料包括基体和位于所述基体表面的保护层，所述保护层包括M元素，所述M元素包括C、Ti、Al、Zn、S、P、B或N中的至少一种。
在一些实施例中，所述基体包括硅氧复合材料、硅碳复合材料或硅单质中的至少一种。
在一些实施例中，基于所述保护层的质量，所述保护层中所述M元素的含量为150ppm至6500ppm。在一些实施例中，基于所述保护层的质量，所述保护层中所述M元素的含量为150ppm至4000ppm。
在一些实施例中，所述负极活性物质层还包括碳材料；基于所述碳材料和所述硅基材料的总质量，所述硅基材料的质量百分含量为2％至80％。
在一些实施例中，所述负极活性物质层的孔隙率为P，20％≤P≤40％。
第二方面，本申请提出了一种电子装置，包括如本申请第一方面任一实施例的电化学装置。
根据本申请实施例的电化学装置，电解液中添加有式(I)化合物，一方面， 其中的不饱和双键，能够在硅基材料表面聚合成膜，从而在SEI膜中引入刚性的桥环结构，抑制硅基材料的体积膨胀；同时，由于式(I)化合物中桥环结构的位阻，可以获得相对较小的成膜阻抗，并且可以抑制循环过程中的副产物在活性材料表面的密堆积，促进锂离子在活性材料和电解液之间的传输；另一方面，式(I)化合物也能够在正极成膜，其中的酸酐/酰胺结构可以抑制电解液中的微量水和酸对正极材料表面电解质界面膜的破坏，从而抑制溶剂在正极表面的氧化分解，进而提升电化学装置的循环性能和高温存储性能。
具体实施方式
本申请的实施例将会被详细的描示在下文中。本申请的实施例不应该被解释为对本申请的限制。
另外，有时在本文中以范围格式呈现量、比率和其它数值。应理解，此类范围格式是用于便利及简洁起见，且应灵活地理解，不仅包含明确地指定为范围限制的数值，而且包含涵盖于范围内的所有个别数值或子范围，如同明确地指定每一数值及子范围一般。
在具体实施方式及权利要求书中，由术语“中的一者或多者”、“中的一个或多个”、“中的一种或多种”或其他相似术语所连接的项目的列表可意味着所列项目的任何组合。例如，如果列出项目A及B，那么短语“A及B中的至少一者”意味着仅A；仅B；或A及B。在另一实例中，如果列出项目A、B及C，那么短语“A、B及C中的至少一者”意味着仅A；或仅B；仅C；A及B(排除C)；A及C(排除B)；B及C(排除A)；或A、B及C的全部。项目A可包含单个元件或多个元件。项目B可包含单个元件或多个元件。项目C可包含单个元件或多个元件。
术语“卤素原子”是指氟原子、氯原子、溴原子或碘原子等。
术语“羧酸酯基”是指含-C(＝O)-O-的基团。
术语“碳酸酯基”是指含-O-C(＝O)-O-的基团。
术语“含氮基团”是指基团中含氮原子的基团。包括胺基、酰胺基等。
术语“含硫基团”是指基团中含硫原子的基团。包括烷硫基、磺酸酯基、硫酸酯基、砜基等。
术语“含硼基团”是指基团中含硼原子的基团。包括硼酸酯基等。
术语“含硅基团”是指基团中含硅原子的基团。包括硅烷基、硅酸酯基等。
术语“含磷基团”是指基团中含磷原子的基团。包括磷酸酯基、亚磷酸酯基等。
电化学装置
第一方面，本申请提出了一种电化学装置，所述电化学装置包括负极极片和电解液；负极极片包括负极活性物质层，负极活性物质层包含硅基材料。所述电解液包括包括式(I)化合物，
Figure PCTCN2022140265-appb-000004
式(I)中，X选自氧原子或N-R 8；R 1、R 2、R 3、R 4、R 5、R 6和R 8各自独立地选自氢原子、卤素原子、经取代或未经取代的C 1至C 10烷基、经取代或未经取代的C 2至C 10烯基、经取代或未经取代的C 2至C 10炔基、经取代或未经取代的C 6至C 10芳基、经取代或未经取代的C 1至C 10烷氧基、经取代或未经取代的C 2至C 10烯氧基、经取代或未经取代的C 2至C 10炔氧基、经取代或未经取代的C 6至C 10芳氧基、经取代或未经取代的C 1至C 10烷氧基烷基、经取代或未经取代的C 1至C 10羧基、经取代或未经取代的C 2至C 10羧酸酯基、经取代或未经取代的C 2至C 10碳酸酯基、氰基、氨基、经取代或未经取代的C 1至C 10含氮基团、经取代或未经取代的C 1至C 10含硫基团、经取代或未经取代的C 1至C 10含硼基团、经取代或未经取代的C 1至C 10含硅基团或经取代或未经取代的C 1至C 10含磷基团；R 7选自经取代或未经取代的C 1至C 10亚烷基、经取代或未经取代的C 3至C 10亚环烷基、经取代或未经取代的C 1至C 10含氧基团或经取代或未经取代的C 1至C 10含氮基团；当经取代时，取代基包括卤素原子或氰基中的至少一种。
电解液中添加有式(I)化合物，一方面，其中的不饱和双键，能够在硅基材料表面聚合成膜，从而在SEI膜中引入刚性的桥环结构，抑制硅基材料的体积膨胀；同时，由于式(I)化合物中桥环结构的位阻，可以获得相对较小的成膜阻抗，并且可以抑制循环过程中的副产物在活性材料表面的密堆积，促进锂离子在活性材料和电解液之间的传输；另一方面，式(I)化合物也能够在正极成膜，其中的酸酐/酰胺结构可以抑制电解液中的微量水和酸对正极材料表面电解质界面膜的破坏，从而抑制溶剂在正极表面的氧化分解，进而提升电化学装置的循环性能和高温存储性能。
在一些实施例中，基于所述负极活性物质层的面积，所述负极活性物质层中硅元素的含量为Y mg/cm 2；基于所述电解液的质量，所述式(I)化合物的质量百分含量为a％；满足：0.1≤a/Y≤20。
随着硅基材料含量的增加(Y增加)，形成和修复SEI膜所需要的式(I)化合物的量也越多，当电化学装置满足0.1≤a/Y时，可以提高对SEI膜的形成和修复效果，抑制硅基材料的体积膨胀和其表面的副反应，从而改善电化学装置的循环性能和高温存储性能；随着式(I)化合物的含量继续增加(a增加)，虽然SEI膜的形成和修复效果得到显著改善，但是在活性材料表面所形成的SEI膜可能过厚，从而增加负极极片的直流阻抗，影响电化学装置的循环性能，由此本申请调 控电化学装置继续满足a/Y≤20，可以改善电化学装置的循环性能。
示例性地，a/Y可以为0.1、0.2、0.5、0.8、1.0、1.5、2、5、6、7、8、9、10、11、12、13、15、17、19、20或是上述任意两个数值组成的范围。可选地，在一些实施例中，0.3≤a/Y≤13.5。
电解液中式(I)化合物含量过大时，成膜阻抗大，不利于锂离子的嵌入和脱出；式(I)化合物含量过小时，不利于在活性材料表面形成致密且均匀的SEI膜，无法对活性材料起到良好的防护；由此，本申请进一步调控0.01≤a≤10，可以形成致密且均匀的SEI膜，能够较好地修复SEI膜，并且所形成的膜层阻抗相对较低，有利于改善电化学装置的动力学性能。示例性地，式(I)化合物的含量a％可以为0.01％、0.02％、0.05％、0.08％、0.1％、0.2％、0.5％、0.8％、1％、1.2％、1.5％、1.8％、2％、2.5％、2.8％、3％、3.5％、3.8％、4％、4.5％、5％、7％、8％、10％或是上述任意两个数值组成的范围。可选地，在一些实施例中，0.1≤a≤5。
负极集流体具有沿其自身厚度方向彼此相对的两个表面，负极活性物质层可以设置于负极集流体的一个表面上，也可以设置于负极集流体的两个表面上。Y表示负极集流体单个表面上负极活性物质层每单位涂布面积中硅元素的质量。由于硅基材料在充放电过程中具有较大的体积变化，本申请进一步调控硅元素的含量满足0.1≤Y≤1.55时，可以保证电化学装置的高能量密度，并显著缓解硅基材料的体积变化问题，有利于改善负极极片的结构稳定性，从而改善电化学装置的循环性能和高温存储性能。示例性地，负极集流体上每单位负极活性物质层涂布面积中硅元素的质量可以为0.1mg/cm 2、0.2mg/cm 2、0.5mg/cm 2、0.8mg/cm 2、0.9mg/cm 2、1.0mg/cm 2、1.1mg/cm 2、1.2mg/cm 2、1.3mg/cm 2、1.4mg/cm 2、1.5mg/cm 2、1.55mg/cm 2或是上述任意两个数值组成的范围。可选地，在一些实施例中，0.1≤Y≤1.2。
[电解液]
在一些实施例中，式(I)化合物包括式(I-1)化合物至式(I-20)化合物中的至少一种：
Figure PCTCN2022140265-appb-000005
Figure PCTCN2022140265-appb-000006
上述化合物，一方面，其分子中的不饱和双键能够在硅基材料表面聚合成膜，另一方面，其环内的C＝O键和-X-键，均可发生断键交联，从而能够在硅基材料的表面发生原位交联反应，使得分子内的刚性桥环结构同步引入到SEI膜中，形成牢固且稳定的SEI膜，抑制硅基材料的体积膨胀，进而改善电化学装置的循环性能和高温存储性能。
在一些实施例中，所述电解液还包括氟代碳酸酯类化合物，基于所述电解液的质量，所述氟代碳酸酯类化合物的质量百分含量为b％，1≤b≤22。氟代碳酸酯类化合物具有氟取代基团，该基团具有较强的吸电子能力，在较高的电位下容易发生还原分解，促进SEI膜的形成和修复；并且所形成的SEI膜阻抗较小，有利于锂离子等的迁移，从而提升电化学装置的循环性能。并且，氟代碳酸酯类化合物高温下分解所产生的HF，能够被式(I)化合物中的酸酐/酰胺结构捕获，抑制其对正极电解质界面膜的破坏，进而保证电化学装置的高温存储性能。
示例性地，氟代碳酸酯类化合物相对于电解液总质量的质量百分含量b％可以为1％、3％、4％、5％、6％、7％、8％、9％、10％、12％、13％、14％、15％、16％、17％、20％、22％或是上述任意两个数值组成的范围。可选地，5≤b≤17。
示例性地，氟代碳酸酯类化合物包括氟代碳酸乙烯酯、氟代碳酸丙烯酯、氟代碳酸二乙酯、二氟代碳酸乙烯酯、二(三氟甲基)碳酸酯、碳酸二(五氟乙基)碳酸酯或二(2,2,2三氟乙基)碳酸酯中的至少一种。
在一些实施例中，电解液还包括羧酸酯类溶剂，基于所述电解液的质量，所述羧酸酯类溶剂的质量百分含量为c％，满足：0.1≤(b/c)/Y≤5.5。电解液中含有羧酸酯类溶剂时，其导离子能力得到大幅度提升，可以降低电化学装置的阻抗，改善电化学装置的循环性能，但羧酸酯类溶剂在硅基材料表面不稳定，容易在负极分解产气，而氟代碳酸酯类化合物能够在较高的电位下发生还原分解，优先于羧酸酯类溶剂在硅基材料表面分解成膜，从而能够有效缓解羧酸酯类溶剂的还原分解，并且，氟代碳酸酯类化合物高温下分解所产生的HF，能够被式(I)化合物中的酸酐/酰胺结构捕获，抑制其对正极电解质界面膜的破坏，进而保证电化学装置的高温存储性能。
本申请调控0.1≤(b/c)/Y≤5.5，可以使得羧酸酯类溶剂、氟代碳酸酯类化合物和式(I)化合物三者协同作用，在保证电化学装置的高温存储性能的基础上，同步改善电化学装置的阻抗和电解液对SEI膜的修复能力，有利于提升电化学装置的循环性能和动力学性能。示例性地，(b/c)/Y可以为0.1、0.2、0.4、0.5、0.8、1.0、1.2、1.5、1.8、2、2.5、2.8、3、3.5、4、5、5.5或是上述任意两个数值组成的范围。可选地，0.5≤(b/c)/Y≤3。
在一些实施例中，5≤c≤70。羧酸酯类溶剂的质量百分含量c％可以为5％、8％、10％、15％、20％、30％、35％、40％、45％、50％、60％、70％或是上述任意两个数值组成的范围。羧酸酯类溶剂具有相对较低的粘度，羧酸酯类溶剂的质量百分含量在上述范围时，能够改善电解液的离子电导率，使得电化学装置能够实现更大的充放电倍率。可选地，5≤c≤60。
可选地，羧酸酯类溶剂包括经取代或未经取代的分子中C原子总数为3至10的羧酸酯；当经取代时，取代基包括卤素原子。
示例性地，所述羧酸酯类溶剂包括乙酸甲酯、乙酸乙酯、乙酸丙酯、乙酸丁酯、丙酸甲酯、丙酸乙酯、丙酸丙酯、丙酸丁酯、氟代乙酸乙酯、氟代乙酸丙酯、氟代乙酸丁酯、氟代丙酸乙酯、氟代丙酸丙酯或氟代丙酸丁酯中的至少一种。
在一些实施例中，电解液还包括不饱和环状碳酸酯类化合物，不饱和环状碳酸酯类化合物包括碳酸亚乙烯酯或碳酸乙烯亚乙酯中的至少一种；基于所述电解液的质量，不饱和环状碳酸酯类化合物的质量百分含量为0.01％至5％。
在一些实施例中，电解液还包括环状磺酸酯类化合物，所述环状磺酸酯类化合物包括1，3-丙烯磺酸内酯、1，3-丙烷磺酸内酯或1,4-丁磺酸内酯中的至少一种；基于电解液的质量，环状磺酸酯类化合物的质量百分含量为0.01％至 5％。
在一些实施例中，电解液还包括不饱和腈类化合物，所述不饱和腈类化合物包括3-己烯二氰或丁烯二腈中的至少一种；基于所述电解液的质量，所述不饱和腈类化合物的质量百分含量为0.01％至5％。
在一些实施例中，电解液还包括不饱和酸酐类化合物，所述不饱和酸酐类化合物包括马来酸酐、2,3-二甲基马来酸酐、衣康酸酐或柠康酸酐中的至少一种；基于所述电解液的质量，所述不饱和酸酐类化合物的质量百分含量为0.01％至5％。
在一些实施例中，电解液还包括不饱和硅烷类化合物，所述不饱和硅烷类化合物包括三烯丙基甲氧基硅烷、烯丙基三甲氧基硅烷、烯丙氧基三甲基硅烷或丙炔氧基三甲基硅烷中的至少一种；基于所述电解液的质量，所述不饱和硅烷类化合物的质量百分含量为0.01％至5％。
上述化合物由于具有双键，在电化学装置充放电过程中能够和式(I)化合物进行交联反应，促使SEI膜的均匀形成，进一步改善电化学装置的循环性能和高温存储性能。
在一些实施例中，电解液还包括其它有机溶剂，例如碳酸酯类溶剂、醚类溶剂中的一种或多种。示例性地，有机溶剂还可以包括碳酸乙烯酯(EC)、碳酸丙烯酯(PC)、碳酸丁烯酯、碳酸甲乙酯、碳酸二甲酯、碳酸二乙酯(DEC)、碳酸二丙酯、碳酸甲丙酯、碳酸乙丙酯、乙二醇二甲醚(DME)、四氢呋喃(THF)和二氧五环(DOL)等中的一种或多种。
本申请的电解液中还含有电解质盐。电解质盐是本领域技术公知的适用于电化学装置的电解质盐。针对不同的电化学装置，可以选用合适的电解质盐。例如对于锂离子电池，电解质盐通常使用锂盐。
在一些实施例中，锂盐包括有机锂盐和无机锂盐中的至少一种。示例性地，锂盐可以包括六氟磷酸锂LiPF 6。
[负极极片]
负极极片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，负极活性物质层包含负极活性材料。
在一些实施例中，负极极片的结构为本领域技术公知的可被用于电化学装置的负极极片的结构。
在一些实施例中，负极集流体为金属，例如但不限于铜箔、镍箔、不锈钢箔、钛箔、泡沫镍、泡沫铜、包覆有导电金属的聚合物基板或它们的组合。
负极活性材料可选用本领域公知的各种可被用作电化学装置的负极活性材料的能够可逆地嵌入、脱嵌活性离子的物质。
在一些实施例中，负极活性材料包含硅基材料。
在一些实施例中，硅基材料包括基体和位于基体表面的保护层，保护层包括M元素，M元素包括碳C元素、钛Ti元素、铝Al元素、锌Zn元素、硫S元素、磷P元素、硼B元素或氮N元素中的至少一种。可选地，基体可以为纳米 颗粒，纳米级别的颗粒能够显著改善硅基材料体积变化的问题，降低体积变化量，由此提高负极活性物质层整体的结构稳定性，改善电化学装置的循环性能。保护层包覆于基体的表面，能够进一步缓解基体的体积变化，并且保护层中的金属离子、碳等能够提高硅基材料的导电性，有利于改善电化学装置的循环性能和高温存储性能；另外，保护层能够减少循环过程中硅基材料表面副产物的产生，有利于进一步提高电化学装置的循环性能。示例性地，保护层的材质包括碳、氧化铝Al 2O 3、氧化钛TiO 2、氧化锌ZnO。
在一些实施例中，基体包括硅氧复合材料、硅碳复合材料或硅单质中的至少一种。具体地，硅氧复合材料的通式为SiOx，0.5≤x≤1.5。硅碳复合材料中可能会存在氧元素；硅碳复合材料中的硅元素的质量含量、碳元素的质量含量和氧元素的质量含量的比值为(1至6)：(1至3)：(1至0)。
在一些实施例中，基于保护层的质量，保护层中M元素的含量为150ppm至6500ppm。保护层能够有效地缓解基体的体积变化，并且有利于基体的容量发挥。示例性地，保护层中M元素的含量可以为150ppm、200ppm、500ppm、800ppm、1000ppm、1500ppm、2000ppm、2500ppm、3000ppm、3500ppm、4000ppm、4500ppm、5000ppm、5500ppm、6000ppm、6500ppm或是上述任意两个数值组成的范围。
在一些实施例中，负极活性材料除了硅基材料外，还可以额外包括锂金属、锂金属合金、碳材料或过渡金属氧化物中的至少一种。可选地，负极活性材料还包括碳材料。在一些实施例中，碳材料可选用本领域技术公知的各种可被用作电化学装置的碳基负极活性材料的碳材料。基于所述碳材料和所述硅基材料的总质量计，所述碳材料的质量百分含量为2％至80％。示例性地，碳材料的质量百分含量为2％、5％、10％、20％、30％、40％、50％、60％、70％、80％或是上述任意两个数值组成的范围。碳材料和硅基材料混合使用能够改善电化学装置的循环性能。、在一些实施例中，碳材料包含天然石墨、人造石墨、结晶石墨、软碳、硬碳、热解碳、中间相沥青基碳纤维、中间相碳微珠、中间相沥青、高温锻烧炭中的至少一种。
在一些实施例中，负极活性物质层还可以包括负极粘结剂，负极活性材料的质量与负极粘结剂的质量的比值为(80至100):(0.5至10)。满足上述质量比的负极极片的综合性能较好，既能使负极活性物质层具有良好的粘结性，又能保证电化学装置具有较高的能量密度。
作为负极粘结剂的示例，负极粘结剂包含二氟乙烯一六氟丙烯共聚物(PVDF-co-HFP)、聚偏二氟乙烯、聚丙烯腈、丙烯酸酯聚合物、聚乙烯醇、羧甲基纤维素、羟丙基纤维素、聚氯乙烯、羧化的聚氯乙烯、聚乙烯吡咯烷酮、聚氨酯、聚四氟乙烯、丁苯橡胶、丙烯酸(酯)化的丁苯橡胶、环氧树脂、尼龙中的至少一种。
在一些实施例中，负极活性物质层还可以包括负极导电剂。作为负极导电剂的示例，负极导电剂用于为电极提供导电性，其可以包括任何导电的材料，只要 它不引起化学变化即可。负极导电剂包含碳基材料、金属基材料、导电聚合物中的任意一种或它们的混合物。在一些实施例中，碳基材料包含炭黑、乙炔黑、科琴黑、碳纤维、碳纳米管、石墨烯中的至少一种。在一些实施例中，金属基材料包含铜、镍、铝、银等的金属粉或金属纤维中的至少一种。在一些实施例中，导电聚合物包含聚亚苯基衍生物。
在一些实施例中，负极极片的制备方法是本领域公知的可被用于电化学装置的负极极片的制备方法。在一些实施例中，在负极浆料的制备中，通常加入负极活性材料和负极粘结剂，并根据需要加入负极导电剂和增稠剂后溶解或分散于溶剂中制成负极浆料。溶剂在干燥过程中挥发去除。溶剂是本领域公知的可被用作负极活性物质层的溶剂，溶剂例如但不限于水。增稠剂是本领域公知的可被用作负极活性物质层的增稠剂，增稠剂例如但不限于羧甲基纤维素钠。
本申请对于负极活性物质层中的负极活性材料、负极粘结剂、增稠剂的混合比例没有特别的限制，可以根据期望的电化学装置性能控制其混合比例。
在一些实施例中，负极活性物质层的孔隙率为P，10％≤P≤50％。负极活性物质层的孔隙率为本领域公知的含义，可以采用本领域公知的设备和方法测试得到，例如可以通过气体置换法得到，孔隙率P＝(V 1-V 2)/V 1×100％，V 1表示表观体积，V 2表示真实体积。
负极活性物质层的孔隙率在上述范围时，可以使得电解液充分浸润负极活性物质层，能够有效缩短锂离子的传输距离，提升电化学装置的动力学性能；并且负极活性物质层内的颗粒接触紧密，在充放电过程中能够始终保持颗粒间的有效接触，从而保证电化学装置的循环性能。示例性地，负极活性物质层的孔隙率P可以为10％、20％、22％、25％、28％、30％、32％、35％、38％、40％、50％或是上述任意两个数值组成的范围。在一些实施例中，20％≤P≤40％。
[正极极片]
正极极片是本领域公知的可被用于电化学装置的正极极片。在一些实施例中，正极极片包含正极集流体以及正极活性物质层。正极活性物质层设置于正极集流体的表面上。正极活性物质层包含正极活性材料。
在一些实施例中，正极极片的结构为本领域技术公知的可被用于电化学装置的正极极片的结构。
在一些实施例中，正极集流体为金属，例如但不限于铝箔。
正极活性材料可选用本领域公知的各种可被用作电化学装置的正极活性材料的能够可逆地嵌入、脱嵌活性离子的物质。对于锂离子电池，正极活性材料中通常包含锂离子。
在一些实施例中，正极活性材料包含能够吸收和释放锂的正极材料，包括但不限于钴酸锂、镍钴锰酸锂、镍钴铝酸锂、锰酸锂、磷酸锰铁锂、磷酸铁锂和富锂锰基材料。
在一些实施例中，正极活性物质层还包含正极粘结剂和正极导电剂。正极粘结剂用于改善正极活性材料颗粒彼此间以及正极活性材料颗粒与集流体的粘结 性能。在一些实施例中，正极粘结剂包括聚乙烯醇、羧甲基纤维素、羟丙基纤维素、二乙酰基纤维素、聚氯乙烯、羧化的聚氯乙烯、聚乙烯吡咯烷酮、聚氨酯、聚四氟乙烯、聚偏二氟乙烯、偏二氟乙烯-六氟丙烯共聚物、丁苯橡胶、丙烯酸(酯)化的丁苯橡胶、环氧树脂、尼龙中的至少一种。正极导电剂用于为电极提供导电性，其可以包括任何导电的材料，只要它不引起化学变化即可。在一些实施例中，正极导电剂包括炭黑、乙炔黑、科琴黑、碳纤维、碳纳米管、石墨烯、金属粉、金属纤维、聚亚苯基衍生物中的至少一种。在一些实施例中，金属粉、金属纤维中的金属包括铜、镍、铝、银中的至少一种。
在一些实施例中，正极极片的制备方法是本领域公知的可被用于电化学装置的正极极片的制备方法。在一些实施例中，在正极浆料的制备中，通常加入正极活性材料、正极粘结剂和正极导电剂后溶解或分散于溶剂中制成正极浆料。溶剂在干燥过程中挥发去除。溶剂是本领域公知的可被用作正极活性物质层的溶剂，溶剂例如但不限于N-甲基吡咯烷酮(NMP)。
[隔离膜]
隔离膜是本领域公知的可被用于电化学装置的隔离膜，例如但不限于聚烯烃类微多孔膜。在一些实施例中，隔离膜包含聚乙烯(PE)、乙烯-丙烯共聚物、聚丙烯(PP)、乙烯-丁烯共聚物、乙烯-己烯共聚、乙烯-甲基丙烯酸甲酯共聚物中的至少一种。
在一些实施例中，隔离膜为单层隔离膜或多层隔离膜。
在一些实施例中，隔离膜上涂覆有涂层。在一些实施例中，涂层包含有机涂层和无机涂层中的至少一种，其中，有机涂层包括聚偏氟乙烯、偏氟乙烯-六氟丙烯共聚物、聚丙烯腈、聚酰亚胺、丙烯腈-丁二烯共聚物、丙烯腈-苯乙烯-丁二烯共聚物、丙烯酸酯聚合物、丙烯酸-苯乙烯共聚物、聚二甲基硅氧烷、聚丙烯酸钠、羧甲基纤维素钠中的至少一种，无机涂层包括无机颗粒和粘结剂，无机颗粒包括SiO 2、Al 2O 3、CaO、TiO 2、ZnO 2、MgO、ZrO 2、SnO 2中至少一种。
本申请对隔离膜的形态和厚度没有特别的限制。隔离膜的制备方法是本领域公知的可被用于电化学装置的隔离膜的制备方法。
电子装置
本申请还提供了一种电子装置，包含本申请前述的电化学装置。
本申请的电子装置是任何电子装置，例如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、锂离子电容器。
下面以锂离子电池为例并且结合对比例及实施例对本申请的技术方案作进一步的说明。在下述实施例、对比例中，所使用到的试剂、材料以及仪器如没有 特殊的说明，均可商购获得或合成获得。
实施例1-1
锂离子电池的制备
(1)正极极片的制备
将正极活性材料钴酸锂(LiCoO 2)、导电剂Super P、粘结剂聚偏二氟乙烯按照重量比97:1.5:1.5进行混合，加入N-甲基吡咯烷酮(NMP)，在真空搅拌机作用下搅拌均匀，获得正极浆料，其中正极浆料的固含量为72wt％；将正极浆料均匀涂覆于正极集流体铝箔的一侧表面上，在85℃下烘干，得到单面涂覆有正极活性物质层的正极极片，在正极集流体铝箔的另一侧表面重复上述步骤，得到双面涂覆有正极活性物质层的正极极片，然后经过冷压、裁片、分切后，在85℃的真空条件下干燥4h，得到正极极片。
(2)负极极片的制备
将负极活性材料(人造石墨和包覆有金属氧化物Al 2O 3(包覆层Al含量为184ppm)的硅氧SiO复合材料)、导电剂Super P、羧甲基纤维素钠(CMC)、丁苯橡胶(SBR)按照重量比96.2:1.5:0.5:1.8进行混合，加入去离子水，在真空搅拌机作用下搅拌均匀，获得负极浆料，其中负极浆料的固含量为54wt％。将负极浆料均匀涂覆在负极集流体铜箔的一侧表面上，在85℃下烘干，得到单面涂覆有负极活性物质层的负极极片，在负极集流体铜箔的另一侧表面重复上述步骤，得到双面涂覆有负极活性物质层的负极极片，然后经过冷压、裁片、分切后，在120℃的真空条件下干燥12h，得到负极极片。通过控制硅基材料在负极活性材料中的质量占比、负极活性物质层的单位面积涂布量，调整负极活性物质层单位涂布面积中硅元素的含量Y为2.0mg/cm 2。
(3)电解液的制备
在干燥的氩气气氛手套箱中，将碳酸乙烯酯(EC)、碳酸丙烯脂(PC)、碳酸二乙酯(DEC)按照重量比1:2:7进行混合，并加入添加剂式(I)化合物，其含量如表1所示；充分搅拌后加入锂盐LiPF 6，混合均匀后获得电解液。其中，基于电解液的质量，LiPF 6的质量浓度为12.5％。
(4)隔离膜的制备
选用8μm厚的聚乙烯(PE)多孔膜作为隔离膜。
(5)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、负极极片之间起到隔离的作用，然后卷绕得到裸电芯；焊接极耳后将裸电芯置于外包装铝塑膜中，将上述制备好的电解液注入到干燥后的裸电芯中，经过真空封装、静置、化成、整形、容量测试等工序，获得软包锂离子电池。
对比例1-1至对比例1-3，与实施例1-1不同的是，调整了有无添加剂以及添加剂的种类。
实施例1-2至实施例1-9，与实施例1-1不同的是，调整了式(I)化合物的种类。
实施例1-10至实施例1-15，与实施例1-1不同的是，调整了式(I)化合物的含量a％。
实施例1-16至实施例1-25，与实施例1-1不同的是，调整了硅基材料在负极活性材料中的质量占比以及负极活性物质层的单位面积涂布量中的至少一者，进而调整了Si元素分布。
对比例2-1，与实施例1-1不同的是，对比例2-1中未添加式(I)化合物，仅添加了FEC和羧酸酯类溶剂。
实施例2-1至实施例2-7，与实施例1-1不同的是，实施例2-1至实施例2-7中添加了FEC。
实施例2-8至实施例2-26，与实施例1-1不同的是，实施例2-8至实施例2-26添加了FEC和羧酸酯类溶剂以及调整了式(I)化合物的种类。
实施例3-1至实施例3-8，与实施例1-1不同的是，添加了含双键的添加剂，并调整了式(I)化合物的含量以及含双键添加剂的种类和含量。
实施例4-1至实施例4-8，与实施例3-3不同的是，调整了有无保护层以及保护层中金属元素的含量。
实施例5-1至实施例5-5，与实施例3-3不同的是，实施例5-1至实施例5-5至少调整了负极活性物质层的孔隙率。
实施例和对比例的相关参数如表1至表5所示。
测试部分：
一、负极极片参数测试
1.负极活性物质层每单位涂布面积中硅元素的含量Y的测定：
取含有一定负极活性物质层涂布面积的负极极片，刮下除负极集流体外的材料，称重，加入一定量的浓硝酸进行微波消解后得溶液，并将所得到的溶液和滤渣进行多次洗涤并定容到一定的体积，通过电感耦合等离子体发射光谱仪ICP-OES测试其中的硅元素的等离子体强度，根据所测元素的标准曲线计算出溶液中的硅含量，从而计算出材料中所含的硅元素的质量；硅元素的质量除以负极活性物质层的面积得到负极活性物质层每单位涂布面积中硅元素的含量Y。
二、锂离子电池性能测试
1、循环性能测试：
将锂离子电池，在35℃下以2C恒流充电至4.45V，然后恒压充电至电流为0.05C，静置5min后，以0.5C放电至3.0V，如此充放电循环500次；第一次放电容量记为C0，第500次循环放电容量记为C1；
循环容量保持率(％)＝C1/C0×100％。
2、存储测试：
将锂离子电池，在常温下以2C恒流充电至4.45V，然后恒压充电至电流为0.05C，放置在70℃高温箱中存储7天，在入炉出炉时，用千分尺分别测试锂离子电池的厚度，入炉厚度记为D0，出炉厚度记为D1；
高温存储厚度增长率(％)＝(D1/D0-1)×100％。
测试结果：
表1
Figure PCTCN2022140265-appb-000007
Figure PCTCN2022140265-appb-000008
表1中，“/”表示未添加该物质。
负极活性物质层单位面积涂布量是指，负极集流体上每单位面积中负极活性物质层的涂布重量，其单位为mg/cm 2。
Si元素分布Y是指，负极活性物质层每单位涂布面积中硅元素的含量，其单位为mg/cm 2。
表1展示了式(I)化合物及Si元素分布对锂离子电池的循环及高温存储性能的影响。结果表明，相比于碳酸亚乙烯酯VC和马来酸酐，式(I)化合物可显著提升锂离子电池的循环性能和高温存储性能。电解液中添加有式(I)化合物，一方面，其分子中的不饱和双键结构可以在硅基材料表面聚合成膜，从而在SEI膜中引入刚性的桥环结构，抑制硅基材料的体积膨胀；同时，由于式(I)化合物中桥环结构的位阻，可以获得相对较小的成膜阻抗，并且可以抑制循环过程中的副产物在活性材料表面的密堆积，促进锂离子在活性材料和电解液之间的传输；另一方面，式(I)化合物也能够在正极成膜，其中的酸酐/酰胺结构可以抑制电解液中的微量水和酸对正极材料表面电解质界面膜的破坏，从而抑制溶剂在正极材料表面的氧化分解，进而提升锂离子电池的循环性能和高温存储性能。
进一步地，当式(I)化合物含量a％为0.1％至5％、Y为0.1至1.2且0.3≤a/Y≤13.5时，锂离子电池的循环性能和高温存储性能均较优，在此范围内既能满足SEI膜形成和修复所需的添加剂的量，也能避免式(I)化合物含量过多导致锂离子电池循环性能的下降。
表2
Figure PCTCN2022140265-appb-000009
Figure PCTCN2022140265-appb-000010
Figure PCTCN2022140265-appb-000011
表2中，“/”表示未添加该物质。表2基于实施例1-1的基础上，展示了FEC及羧酸酯类溶剂对锂离子电池的循环及高温存储性能的影响。结果表明，FEC的加入可以改善锂离子电池的长循环性能，这是由于，氟代碳酸酯类化合物具有氟取代基团，该基团具有较强的吸电子能力，在较高的电位下容易发生还原分解，促进SEI膜的形成和修复；并且所形成的SEI膜阻抗较小，有利于锂离子等的迁移，从而提升锂离子电池的循环性能。并且，氟代碳酸酯类化合物高温下分解所产生的HF，能够被式(I)化合物中的酸酐/酰胺结构捕获，抑制其对正极电解质界面膜的破坏，进而保证电化学装置的高温存储性能。此外，FEC和羧酸酯类溶剂的共同加入可以进一步改善锂离子电池的长循环性能。电解液中加入羧酸酯类溶剂时，其导离子能力得到大幅度提升，可以降低锂离子电池的阻抗，改善锂离子电池的循环性能，但羧酸酯类溶剂在硅基材料表面不稳定，容易在负极分解产气，而氟代碳酸酯类化合物能够在较高的电位下发生还原分解，优先于羧酸酯类溶剂在硅基材料表面分解成膜，从而能够有效缓解羧酸酯类溶剂的还原分解，并且，氟代碳酸酯类化合物高温下分解所产生的HF，能够被式(I)化合物中的酸酐/酰胺结构捕获，抑制其对正极电解质界面膜的破坏，进而保证锂离子电池的高温存储性能。进一步地，满足5≤b≤17、0.5≤(b/c)/Y≤3时，锂离子电池的循环性能和高温存储性能均较优。
表3
Figure PCTCN2022140265-appb-000012
表3中，“/”表示未添加该物质。表3展示了基于实施例1-1的基础上，进一步加入其他含双键化合物对锂离子电池的循环及高温存储性能的影响。结果表明，在含有式(I)化合物时，进一步加入其他含双键添加剂可以大幅度改善锂离子电池的循环及高温存储性能，这是因为含双键的上述添加剂可以和式(I)化合 物在充放电时发生交联反应，促进SEI膜的均匀形成，进一步改善锂离子电池的循环性能和高温存储性能。
表4
Figure PCTCN2022140265-appb-000013
表4中，“/”表示未添加该物质。表4展示了基于实施例3-3的基础上，在含硅基体材料表面包覆保护层对电池的循环及高温存储性能的影响。结果表明，通过在含硅基体材料表面设置保护层(金属氧化物)，可以改善电池的循环及高温存储性能，主要是因为保护层能够缓解含硅材料在充放电过程中的体积膨胀，并且保护层中的金属离子能够提高硅基材料的导电性，从而改善电池的循环及高温存储性能。
表5
Figure PCTCN2022140265-appb-000014
表5展示了基于实施例3-3的基础上，变更负极活性物质层孔隙率对电池的 循环及高温存储性能的影响。结果表明，负极活性物质层的孔隙率为20％至40％时能保证优异的循环及高温存储性能。
尽管已经演示和描述了说明性实施例，本领域技术人员应该理解上述实施例不能被解释为对本申请的限制，并且可以在不脱离本申请的精神、原理及范围的情况下对实施例进行改变，替代和修改。

Claims (11)

  1. 一种电化学装置，包括负极极片和电解液；
    所述负极极片包括负极活性物质层，所述负极活性物质层包括硅基材料；
    所述电解液包括式(I)化合物，
    Figure PCTCN2022140265-appb-100001
    式(I)中，
    X选自氧原子或N-R 8；
    R 1、R 2、R 3、R 4、R 5、R 6和R 8各自独立地选自氢原子、卤素原子、经取代或未经取代的C 1至C 10烷基、经取代或未经取代的C 2至C 10烯基、经取代或未经取代的C 2至C 10炔基、经取代或未经取代的C 6至C 10芳基、经取代或未经取代的C 1至C 10烷氧基、经取代或未经取代的C 2至C 10烯氧基、经取代或未经取代的C 2至C 10炔氧基、经取代或未经取代的C 6至C 10芳氧基、经取代或未经取代的C 1至C 10烷氧基烷基、经取代或未经取代的C 1至C 10羧基、经取代或未经取代的C 2至C 10羧酸酯基、经取代或未经取代的C 2至C 10碳酸酯基、氰基、氨基、经取代或未经取代的C 1至C 10含氮基团、经取代或未经取代的C 1至C 10含硫基团、经取代或未经取代的C 1至C 10含硼基团、经取代或未经取代的C 1至C 10含硅基团或经取代或未经取代的C 1至C 10含磷基团；
    R 7选自经取代或未经取代的C 1至C 10亚烷基、经取代或未经取代的C 3至C 10亚环烷基、经取代或未经取代的C 1至C 10含氧基团或经取代或未经取代的C 1至C 10含氮基团；
    当经取代时，取代基包括卤素原子或氰基中的至少一种。
  2. 根据权利要求1所述的电化学装置，其中，基于所述负极活性物质层的面积，所述负极活性物质层中硅元素的含量为Y mg/cm 2；基于所述电解液的总质量，所述式(I)化合物的质量百分含量为a％；满足：0.1≤a/Y≤20。
  3. 根据权利要求2所述的电化学装置，其中，所述电化学装置满足下列条件中的至少一者：
    (1)0.3≤a/Y≤13.5；
    (2)0.01≤a≤10；
    (3)0.1≤Y≤1.55。
  4. 根据权利要求1所述的电化学装置，其中，式(I)化合物包括式(I-1)化合物至式(I-20)化合物中的至少一种：
    Figure PCTCN2022140265-appb-100002
    Figure PCTCN2022140265-appb-100003
  5. 根据权利要求1或2所述的电化学装置，其中，所述电解液还包括氟代碳酸酯类化合物，基于所述电解液的总质量，所述氟代碳酸酯类化合物的质量百分含量为b％，1≤b≤22。
  6. 根据权利要求5所述的电化学装置，其中，基于所述负极活性物质层的面积，所述负极活性物质层中硅元素的含量为Y mg/cm 2；所述电解液还包括羧酸酯类溶剂，基于所述电解液的总质量，所述羧酸酯类溶剂的质量百分含量为c％，满足：0.5≤(b/c)/Y≤3。
  7. 根据权利要求6所述的电化学装置，其中，所述电化学装置满足下列条件中的至少一者：
    (1)5≤b≤17；
    (2)5≤c≤70；
    (3)所述氟代碳酸酯类化合物包括氟代碳酸乙烯酯、氟代碳酸丙烯酯、氟代碳酸二乙酯、二氟代碳酸乙烯酯、二(三氟甲基)碳酸酯、碳酸二(五氟乙基)碳酸酯或二(2,2,2三氟乙基)碳酸酯中的至少一种；
    (4)所述羧酸酯类溶剂包括经取代或未经取代的分子中C原子总数为3至10的羧酸酯；当经取代时，取代基包括卤素原子；
    (5)所述羧酸酯类溶剂包括乙酸甲酯、乙酸乙酯、乙酸丙酯、乙酸丁酯、丙酸甲酯、丙酸乙酯、丙酸丙酯、丙酸丁酯、氟代乙酸乙酯、氟代乙酸丙酯、氟代乙酸丁酯、氟代丙酸乙酯、氟代丙酸丙酯或氟代丙酸丁酯中的至少一种。
  8. 根据权利要求1所述的电化学装置，其中，所述电化学装置满足下列条件中的至少一者：
    (1)所述电解液还包括不饱和环状碳酸酯类化合物，所述不饱和环状碳酸酯类化合物包括碳酸亚乙烯酯或碳酸乙烯亚乙酯中的至少一种；基于所述电解液的总质量，所述不饱和环状碳酸酯类化合物的质量百分含量为0.01％至5％；
    (2)所述电解液还包括环状磺酸酯类化合物，所述环状磺酸酯类化合物包括1，3-丙烯磺酸内酯、1，3-丙烷磺酸内酯或1,4-丁磺酸内酯中的至少一种；
    基于所述电解液的总质量，所述环状磺酸酯类化合物的质量百分含量为0.01％至5％；
    (3)所述电解液还包括不饱和腈类化合物，所述不饱和腈类化合物包括3- 己烯二氰或丁烯二腈中的至少一种；基于所述电解液的总质量，所述不饱和腈类化合物的质量百分含量为0.01％至5％；
    (4)所述电解液还包括不饱和酸酐类化合物，所述不饱和酸酐类化合物包括马来酸酐、2,3-二甲基马来酸酐、衣康酸酐或柠康酸酐中的至少一种；基于所述电解液的总质量，所述不饱和酸酐类化合物的质量百分含量为0.01％至5％；
    (5)所述电解液还包括不饱和硅烷类化合物，所述不饱和硅烷类化合物包括三烯丙基甲氧基硅烷、烯丙基三甲氧基硅烷、烯丙氧基三甲基硅烷或丙炔氧基三甲基硅烷中的至少一种；基于所述电解液的总质量，所述不饱和硅烷类化合物的质量百分含量为0.01％至5％。
  9. 根据权利要求1所述的电化学装置，其中，所述硅基材料包括基体和位于所述基体表面的保护层，所述保护层包括M元素，所述M元素包括C、Ti、Al、Zn、S、P、B或N中的至少一种；所述电化学装置满足下列条件中的至少一者：
    (1)所述基体包括硅氧复合材料、硅碳复合材料或硅单质中的至少一种；
    (2)基于所述保护层的质量，所述保护层中所述M元素的含量为150ppm至6500ppm。
  10. 根据权利要求1所述的电化学装置，其中，所述电化学装置满足下列条件中的至少一者：
    (1)所述负极活性物质层还包括碳材料；基于所述碳材料和所述硅基材料的总质量，所述硅基材料的质量百分含量为2％至80％；
    (2)所述负极活性物质层的孔隙率为P，20％≤P≤40％。
  11. 一种电子装置，包括如权利要求1至10中任一项所述的电化学装置。
PCT/CN2022/140265 2022-12-20 2022-12-20 电化学装置及电子装置 Ceased WO2024130535A1 (zh)

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