WO2023070674A1 - 一种电解液、包含该电解液的电化学装置及电子装置 - Google Patents

一种电解液、包含该电解液的电化学装置及电子装置 Download PDF

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WO2023070674A1
WO2023070674A1 PCT/CN2021/127986 CN2021127986W WO2023070674A1 WO 2023070674 A1 WO2023070674 A1 WO 2023070674A1 CN 2021127986 W CN2021127986 W CN 2021127986W WO 2023070674 A1 WO2023070674 A1 WO 2023070674A1
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electrolyte
lithium
formula
substituted
electrochemical device
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PCT/CN2021/127986
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English (en)
French (fr)
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刘建
唐超
林孟衍
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东莞新能源科技有限公司
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Priority to CN202180054795.2A priority Critical patent/CN116235331A/zh
Priority to PCT/CN2021/127986 priority patent/WO2023070674A1/zh
Publication of WO2023070674A1 publication Critical patent/WO2023070674A1/zh

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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
    • 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
    • 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 technical field of electrochemistry, and in particular to an electrolyte, an electrochemical device and an electronic device containing the electrolyte.
  • Lithium-ion batteries have the advantages of high energy storage density, high open circuit voltage, low self-discharge rate, long cycle life, and good safety. They have been widely used as power sources in cameras, mobile phones, drones, laptops, and smart watches product.
  • the purpose of the present application is to provide an electrolytic solution, an electrochemical device and an electronic device containing the electrolytic solution, so as to improve the cycle performance and safety performance of the electrochemical device.
  • the first aspect of the present application provides an electrolyte, which includes a compound represented by formula (I), based on the quality of the electrolyte, the mass percentage X of the compound represented by formula (I) is 0.05% to 3%:
  • R 1 and R 2 are each independently selected from H, F, C 1 to C 5 alkyl, C 1 to C 5 alkoxy or C 2 to C 5 alkenyl, C 2 to C 5 Alkynyl;
  • R is selected from O or -CH(R 3 )-,
  • R 3 is selected from H, F, C 1 to C 5 alkyl, or C 1 to C 5 alkoxy;
  • Rb is selected from H, F , C 1 to C 5 alkyl, or C 1 to C 5 alkoxy;
  • a and B are each independently selected from -CO- or -SO 2 -;
  • W is selected from CH 2 or O;
  • M - is selected from One of the groups M1 to M3:
  • Electrolyte solution comprises the compound shown in formula (I), and the mass percentage content X of the compound shown in formula (I) is 0.05% to 3%, is conducive to forming a stable positive electrode electrolyte interface (CEI) on the positive electrode surface, on the negative electrode surface
  • a stable solid electrolyte interface (SEI) can reduce the side reaction between the electrolyte and the positive active material or negative active material, and improve the cycle performance and safety performance of the electrochemical device.
  • the electrolyte includes at least one of the following compounds I-1 to I-13:
  • the electrolyte also includes a cyclic sulfonate
  • the cyclic sulfonate includes a cyclic monosulfonate and/or a cyclic disulfonate, based on the quality of the electrolyte, the cyclic sulfonate
  • the mass percentage of acid ester is 0.01% to 10%
  • cyclic monosulfonate includes 1,3-propane sultone, 1,2-propane sultone, 1,4-butane sultone At least one of ester, 1,2-butane sultone, 1,3-butane sultone, 2,4-butane sultone or 1,3-pentane sultone
  • cyclic disulfonates include methylene methanedisulfonate and/or ethylene methanedisulfonate.
  • cyclic monosulfonic acid ester By selecting the above-mentioned cyclic monosulfonic acid ester, it is beneficial to improve the cycle performance and safety performance of the electrochemical device.
  • cyclic sulfonate and regulating the mass percentage of the cyclic sulfonate within the above-mentioned range it is beneficial to improve the cycle performance and safety performance of the electrochemical device.
  • the electrolyte includes a compound represented by formula (II):
  • D and E are each independently selected from a C 1 to C 8 alkylene group or a C 1 to C 8 fluoroalkylene group, and L is selected from a single bond or -OSO 2 -.
  • the electrolyte includes a compound shown in formula (II-1) and/or a compound shown in formula (II-2):
  • R 6 and R 7 are each independently selected from H, F or C 1 to C 4 alkyl, n3 is 1, 2, 3 or 4;
  • D and E are each independently selected from C 1 to C 8 alkylene or C 1 to C 8 fluoroalkylene.
  • the electrolyte also includes a compound represented by formula (III), based on the mass of the electrolyte, the mass percentage content C of the compound represented by formula (III) is 0.5% to 16%, and 0.03 ⁇ X/C ⁇ 1:
  • R 12 to R 15 are each independently selected from H, F, C 1 to C 10 fluoroalkyl, C 1 to C 10 fluoroalkoxy or C 1 to C 10 fluoroalkoxy Alkyl, and R 12 to R 15 are not H at the same time.
  • the electrolyte includes at least one of the following compounds III-1 to III-6:
  • the electrolyte also includes a cyano-containing compound
  • the cyano-containing compound includes at least one of the compounds shown in formula (IV) to formula (VII), based on the quality of the electrolyte, the cyano-containing
  • the mass percentage content D of compound is 0.2% to 10%:
  • R 16 is selected from unsubstituted or substituted C 1 to C 12 alkylene, unsubstituted or substituted C 1 to C 12 alkyleneoxy;
  • R 17 and R 18 are each independently selected from From a single bond, unsubstituted or substituted C 1 to C 12 alkylene, unsubstituted or substituted C 1 to C 12 alkyleneoxy;
  • R 19 to R 21 are each independently selected from a single Bond, C 1 to C 12 alkylene unsubstituted or substituted by Ra, C 1 to C 12 alkyleneoxy unsubstituted or substituted by Ra, C 1 to C 12 unsubstituted or substituted by Ra Alkyleneoxyalkyl;
  • R 22 and R 23 are each independently selected from unsubstituted or substituted C 1 to C 12 alkylene groups, unsubstituted or substituted C 2 to C 12 alkenylene groups , unsubstituted or substituted by Ra C 6 to C 26 arylene group, unsub
  • 0.05 ⁇ X/D 0.05 ⁇ X/D ⁇ 1.
  • the electrolyte solution includes at least one of the following compounds IV-1 to IV-4, V-1 to V-3, VI-1 to VI-4, VII-1 or VIII-1 kind:
  • the electrolyte solution satisfies at least one of the following conditions: (i) the electrolyte solution includes a first lithium salt, and the first lithium salt includes lithium hexafluorophosphate, lithium bistrifluoromethanesulfonimide, bis( At least one of lithium fluorosulfonyl imide or lithium difluorooxalate borate, based on the mass of the electrolyte, the mass percentage Y of the first lithium salt is 5% to 13%; (ii) the electrolyte includes the second The lithium salt, the second lithium salt includes lithium difluorophosphate and/or lithium bisoxalate borate, based on the mass of the electrolyte, the mass percentage Y1 of the second lithium salt is 0.05% to 1%.
  • the mass percentage content of the first lithium salt and/or the second lithium salt is controlled within the above-mentioned range, which is beneficial to the first lithium salt and/or the second lithium salt Form a synergistic effect with the electrolyte, thereby improving the cycle performance and safety performance of the electrochemical device.
  • the second aspect of the present application provides an electrochemical device, including the positive electrode and the electrolyte in any of the foregoing embodiments.
  • the electrochemical device After the electrochemical device has undergone at least 400 cycles, in the Raman spectrum of the positive electrode obtained by disassembly, Satisfy 2 ⁇ R2/R1 ⁇ 4, wherein, R1 is the maximum peak intensity value between 620cm -1 and 700cm -1 , and R2 is the maximum peak intensity value between 500cm -1 and 600cm -1 .
  • the electrochemical device also includes a negative electrode, and the negative electrode includes a negative electrode material layer. After the electrochemical device passes through at least 400 cycles, based on the quality of the negative electrode material layer, the mass of Co on the surface of the negative electrode that is disassembled is obtained. Mineral content is less than or equal to 0.12%.
  • the electrochemical device satisfies at least one of the following conditions: (iii) in the range of 140°C to 163°C in differential scanning calorimetry (DSC) with a heating rate of 10°C/min At least one endothermic peak appears within; (iv) the electrochemical device also includes a separator, and the thermal shrinkage rate of the separator at 135 ° C is 2% to 5%, wherein the thermal shrinkage rate includes thermal shrinkage in the width direction (TD direction) Rate and length direction (MD direction) heat shrinkage.
  • DSC differential scanning calorimetry
  • the third aspect of the present application provides an electronic device, comprising the electrochemical device in any one of the foregoing embodiments of the present application.
  • the application provides an electrolyte, an electrochemical device and an electronic device containing the electrolyte, the electrolyte includes a compound represented by formula (I), and the mass percentage X of the compound represented by formula (I) is 0.05% to 3% %, it is beneficial to form a stable CEI on the surface of the positive electrode and a stable SEI on the surface of the negative electrode.
  • FIG. 1 is a Raman spectrum of the positive electrode disassembled in Example 1-4 and Comparative Example 1-1 of the present application.
  • a lithium-ion battery is used as an example of an electrochemical device to explain the present application, but the electrochemical device of the present application is not limited to the lithium-ion battery.
  • the first aspect of the present application provides an electrolyte, which includes a compound represented by formula (I), based on the mass of the electrolyte, the mass percentage X of the compound represented by formula (I) is 0.05% to 3%:
  • R 1 and R 2 are each independently selected from H, F, C 1 to C 5 alkyl, C 1 to C 5 alkoxy or C 2 to C 5 alkenyl, C 2 to C 5 Alkynyl;
  • R is selected from O or -CH(R 3 )-,
  • R 3 is selected from H, F, C 1 to C 5 alkyl, or C 1 to C 5 alkoxy;
  • Rb is selected from H, F , C 1 to C 5 alkyl, or C 1 to C 5 alkoxy;
  • a and B are each independently selected from -CO- or -SO 2 -;
  • W is selected from CH 2 or O;
  • M - is selected from One of the groups M1 to M3:
  • the mass percentage X of the compound represented by formula (I) can be 0.05%, 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3% or any range therebetween.
  • the inventors of the present application have found that the electrolyte includes the compound shown in formula (I), and the mass percentage content X of the compound shown in formula (I) is 0.05% to 3%, which is conducive to the formation of
  • the stable CEI forms a stable SEI on the surface of the negative electrode, which can reduce the side reaction between the electrolyte and the positive active material or the negative active material.
  • the compound represented by formula (I) is one of the following compounds I-1 to I-13.
  • the electrolyte includes at least one of the following compounds I-1 to I-13:
  • the electrolyte also includes a cyclic sulfonate
  • the cyclic sulfonate includes a cyclic monosulfonate and/or a cyclic disulfonate, based on the quality of the electrolyte, the cyclic sulfonate
  • the mass percentage of acid ester is 0.01% to 10%, preferably 0.1% to 5%
  • cyclic monosulfonate includes 1,3-propane sultone, 1,2-propane sultone, 1 ,4-butane sultone, 1,2-butane sultone, 1,3-butane sultone, 2,4-butane sultone or 1,3-pentane sultone
  • cyclic disulfonate esters include methylene methane disulfonate and/or ethylene methane disulfonate.
  • the mass percent content of cyclic sulfonic acid ester can be 0.01%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% or for any range in between.
  • the inventors of the present application have found that when the mass percentage of cyclic sulfonic acid ester is too low (for example, less than 0.01%), stable SEI and CEI cannot be formed, thereby reducing the electrolyte and positive electrode active material. And the side reaction between negative electrode active materials can not improve the cycle performance and safety performance of the electrochemical device.
  • the electrolyte includes a compound represented by formula (II):
  • D and E are each independently selected from a C 1 to C 8 alkylene group or a C 1 to C 8 fluoroalkylene group, and L is selected from a single bond or -OSO 2 -.
  • the electrolytic solution includes a compound shown in formula (II-1):
  • R 6 and R 7 are each independently selected from H, F or C 1 to C 4 alkyl, n3 is 1, 2, 3 or 4.
  • the compound represented by the formula (II-1) is a cyclic monosulfonic ester, and by selecting the cyclic monosulfonic ester represented by the formula (II-1), it is beneficial to improve the cycle performance and safety performance of the electrochemical device.
  • the electrolytic solution includes a compound shown in formula (II-2):
  • D and E are each independently selected from C 1 to C 8 alkylene or C 1 to C 8 fluoroalkylene.
  • the compound represented by the formula (II-2) is the cyclic disulfonic ester, and the selection of the cyclic disulfonic ester represented by the formula (II-2) is beneficial to improve the cycle performance and safety performance of the electrochemical device.
  • the electrolyte includes compounds shown in formula (II-1) and compounds shown in formula (II-2), that is, the electrolyte includes cyclic monosulfonic acid esters and cyclic disulfonic acid esters .
  • the ratio of cyclic monosulfonate and cyclic disulfonate is not particularly limited, as long as the purpose of this application can be achieved , for example, the mass ratio of cyclic monosulfonate and cyclic disulfonate is 1:1.
  • the electrolyte also includes a compound represented by formula (III), based on the mass of the electrolyte, the mass percentage content C of the compound represented by formula (III) is 0.5% to 16%, and 0.03 ⁇ X/C ⁇ 1, preferably 0.03 ⁇ X/C ⁇ 0.2:
  • R 12 to R 15 are each independently selected from H, F, C 1 to C 10 fluoroalkyl, C 1 to C 10 fluoroalkoxy or C 1 to C 10 fluoroalkoxy Alkyl, and R 12 to R 15 are not H at the same time.
  • the compound represented by formula (III) is one of the following compounds III-1 to III-6.
  • the electrolyte includes at least one of the following compounds III-1 to III-6:
  • the mass percentage C of the compound represented by formula (III) can be 0.5%, 1%, 2%, 5%, 8%, 10%, 12%, 15%, 16% or any range therebetween,
  • the value of X/C can be 0.03, 0.05, 0.1, 0.2, 0.3, 0.5, 0.8, 1 or any range therebetween.
  • the inventors of the present application have found that the electrolyte includes the compound shown in formula (III), which is beneficial to improve the stability of SEI, helps to reduce the side reaction between the electrolyte and the negative electrode active material, and improves the electrochemical performance.
  • the electrolyte also includes a cyano-containing compound
  • the cyano-containing compound includes at least one of the compounds shown in formula (IV) to formula (VII), based on the quality of the electrolyte, the cyano-containing
  • the mass percentage content D of compound is 0.2% to 10%:
  • R 16 is selected from unsubstituted or substituted C 1 to C 12 alkylene, unsubstituted or substituted C 1 to C 12 alkyleneoxy;
  • R 17 and R 18 are each independently selected from From a single bond, unsubstituted or substituted C 1 to C 12 alkylene, unsubstituted or substituted C 1 to C 12 alkyleneoxy;
  • R 19 to R 21 are each independently selected from a single Bond, C 1 to C 12 alkylene unsubstituted or substituted by Ra, C 1 to C 12 alkyleneoxy unsubstituted or substituted by Ra, C 1 to C 12 unsubstituted or substituted by Ra Alkyleneoxyalkyl;
  • R 22 and R 23 are each independently selected from unsubstituted or substituted C 1 to C 12 alkylene groups, unsubstituted or substituted C 2 to C 12 alkenylene groups , unsubstituted or substituted by Ra C 6 to C 26 arylene group, unsub
  • the compound shown in formula (IV) is one of the following compounds IV-1 to IV-4
  • the compound shown in formula (V) is one of the following compounds V-1 to V-3
  • the formula The compound represented by (VI) is one of the following compounds VI-1 to VI-4
  • the compound represented by formula (VII) is VII-1
  • the compound represented by formula (VIII) is VIII-1.
  • the electrolyte solution includes at least one of the following compounds IV-1 to IV-4, V-1 to V-3, VI-1 to VI-4, VII-1 or VIII-1 kind:
  • the mass percentage D of the cyano compound is 0.2%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or any range in between.
  • the inventors of the present application have found that the energy level of the lone pair of electrons in the cyano group in the cyano group is close to the energy level of the vacant orbital in the outermost layer of the transition metal atom in the positive electrode active material, so that the cyano group contains
  • the compound can form a complex structure with the positive electrode active material on the surface of the positive electrode, which can reduce the side reaction between the electrolyte and the positive electrode active material, and is beneficial to improve the cycle performance and high-temperature storage performance of the electrochemical device.
  • the mass percentage D of the cyano-containing compound is too high (for example, higher than 10%)
  • the cyano-containing compound forms too many complex structures with the positive electrode active material, which affects the transmission of lithium ions, thereby affecting the performance of the electrochemical device.
  • Kinetic properties such as impedance and cycle performance.
  • 0.05 ⁇ X/D In some embodiments of the present application, 0.05 ⁇ X/D ⁇ 1.
  • the value of X/D can be 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1 or any range therebetween.
  • the electrolyte solution further includes a lithium salt
  • the lithium salt includes at least one of fluorine, boron, or phosphorus.
  • the inventors of the present application found that the above-mentioned elements contained in the lithium salt are conducive to the formation of a synergistic effect between the lithium salt and the electrolyte, thereby improving the cycle performance and safety performance of the electrochemical device.
  • the electrolytic solution satisfies at least one of the following conditions: (i) the electrolytic solution includes a first lithium salt, and the first lithium salt includes lithium hexafluorophosphate, lithium bistrifluoromethanesulfonylimide, bis At least one of lithium (fluorosulfonyl) imide or lithium difluorooxalate borate, based on the mass of the electrolyte, the mass percentage Y of the lithium salt is 5% to 13%; (ii) the electrolyte includes the second The lithium salt, the second lithium salt includes lithium difluorophosphate and/or lithium bisoxalate borate, based on the mass of the electrolyte, the mass percentage Y1 of lithium difluorophosphate and/or lithium bisoxalate borate is 0.05% to 1%.
  • the mass percentage Y of the first lithium salt may be 5%, 8%, 10%, 13%, or any range therebetween.
  • the mass percentage Y1 of the second lithium salt can be 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, or therebetween any range.
  • the second aspect of the present application provides an electrochemical device, including the positive electrode and the electrolyte in any of the foregoing embodiments.
  • the electrochemical device After the electrochemical device has undergone at least 400 cycles, in the Raman spectrum of the positive electrode obtained by disassembly, Satisfy 2 ⁇ R2/R1 ⁇ 4, wherein, R1 is the maximum peak intensity value between 620cm -1 and 700cm -1 , and R2 is the maximum peak intensity value between 500cm -1 and 600cm -1 .
  • the value of R2/R1 can be 2, 2.2, 2.5, 2.8, 3, 3.3, 3.5, 3.7, 4 or any range therebetween. If the value of R2/R1 is within the above range, the positive electrode can maintain a stable crystal structure in the electrolyte solution provided by the present application, further improving the cycle performance of the electrochemical device.
  • the electrochemical device also includes a negative electrode, and the negative electrode includes a negative electrode material layer.
  • the electrochemical device passes through at least 400 cycles, based on the quality of the negative electrode material layer, the mass of Co on the surface of the negative electrode that is disassembled is obtained.
  • the component content is less than or equal to 0.12%, indicating that the electrolyte solution provided by the application effectively inhibits the dissolution of cobalt in the positive electrode material, and can effectively improve the cycle performance of the electrochemical device.
  • the electrochemical device satisfies at least one of the following conditions: (iii) in the range of 140°C to 163°C in differential scanning calorimetry (DSC) with a heating rate of 10°C/min At least one endothermic peak appears within; (iv) the electrochemical device further includes a separator, and the thermal shrinkage rate of the separator at 135° C. is 2% to 5%.
  • the temperature corresponding to the endothermic peak can be 140°C, 145°C, 150°C, 155°C, 160°C, 163°C or any range therebetween. It shows that the positive electrode has good thermal stability.
  • the heat shrinkage rate of the separator at 135° C. may be 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, or any range therebetween. It shows that the separator has good thermal stability, which is beneficial to improve the safety performance of the electrochemical device.
  • the positive electrode usually includes a positive electrode current collector and a positive electrode material layer.
  • the positive electrode current collector is not particularly limited, as long as the purpose of this application can be achieved, for example, it may include but not limited to aluminum foil, aluminum alloy foil or composite current collector.
  • the thickness of the positive electrode collector there is no particular limitation on the thickness of the positive electrode collector, as long as the purpose of the present application can be achieved, for example, the thickness is 8 ⁇ m to 12 ⁇ m.
  • the positive electrode material layer may be provided on one surface in the thickness direction of the positive electrode current collector, or on two surfaces in the thickness direction of the positive electrode current collector. It should be noted that the "surface” here may refer to the entire area of the positive electrode collector or a partial area of the positive electrode collector. This application is not particularly limited, as long as the purpose of this application can be achieved.
  • the positive electrode material layer includes the positive electrode active material
  • the present application has no special limitation on the positive electrode active material, as long as the purpose of the application can be achieved, for example, at least one of the composite oxides of lithium or transition metal elements can be included .
  • the present application has no particular limitation on the above transition metal elements, as long as the purpose of the present application can be achieved, for example, at least one of nickel, manganese, cobalt or iron may be included.
  • the positive electrode active material may include lithium nickel cobalt manganese oxide (811, 622, 523, 111), lithium nickel cobalt aluminate, lithium iron phosphate, lithium-rich manganese-based materials, lithium cobalt oxide, lithium manganate, iron manganese phosphate At least one of lithium or lithium titanate.
  • the positive electrode material layer may also include a binder, and the present application has no particular limitation on the binder, as long as the purpose of the present application can be achieved, for example, it may include but not limited to polyacrylic acid, sodium polyacrylate, potassium polyacrylate, lithium polyacrylate, At least one of polyimide, polyvinyl alcohol, carboxymethyl cellulose, sodium carboxymethyl cellulose, polyimide, polyamideimide, styrene-butadiene rubber or polyvinylidene fluoride.
  • a conductive agent may also be included in the positive electrode material layer, and the present application has no special limitation on the conductive agent, as long as the purpose of the application can be realized, for example, it may include but not limited to conductive carbon black (Super P), carbon nanotubes (CNTs), carbon fiber, flake graphite, Ketjen black, graphene, metal material or conductive polymer.
  • the aforementioned carbon nanotubes may include, but are not limited to, single-walled carbon nanotubes and/or multi-walled carbon nanotubes.
  • the aforementioned carbon fibers may include, but are not limited to, vapor grown carbon fibers (VGCF) and/or carbon nanofibers.
  • the above metal material may include but not limited to metal powder and/or metal fiber, specifically, the metal may include but not limited to at least one of copper, nickel, aluminum or silver.
  • the aforementioned conductive polymer may include but not limited to at least one of polyphenylene derivatives, polyaniline, polythiophene, polyacetylene or polypyrrole.
  • the positive electrode may further include a conductive layer located between the positive electrode current collector and the positive electrode material layer.
  • the present application has no particular limitation on the composition of the conductive layer, which may be a commonly used conductive layer in the field, for example, may include but not limited to the above-mentioned conductive agent and the above-mentioned binder.
  • the negative electrode usually includes a negative electrode current collector.
  • This application has no special restrictions on the negative electrode current collector, as long as the purpose of this application can be achieved.
  • it can include but not limited to copper foil, copper alloy foil, nickel foil, stainless steel foil, titanium foil, foam Nickel, copper foam or composite current collector, etc.
  • the thickness of the current collector of the negative electrode there is no particular limitation on the thickness of the current collector of the negative electrode, as long as the purpose of the present application can be achieved, for example, the thickness is 4 ⁇ m to 12 ⁇ m.
  • the negative electrode material layer may be provided on one surface in the thickness direction of the negative electrode current collector, or on two surfaces in the thickness direction of the negative electrode current collector. It should be noted that the "surface” here may be the entire area of the negative electrode collector, or a partial area of the negative electrode collector. This application is not particularly limited, as long as the purpose of this application can be achieved.
  • the negative electrode material layer includes negative electrode active materials, wherein the negative electrode active material is not particularly limited, as long as the purpose of the application can be achieved, for example, it can include but not limited to natural graphite, artificial graphite, mesophase micro carbon spheres, hard Carbon, soft carbon, silicon, silicon-carbon composite, Li-Sn alloy, Li-Sn-O alloy, Sn, SnO, SnO 2 , lithiated TiO 2 -Li 4 Ti 5 O 12 or Li with spinel structure - at least one of Al alloys.
  • the negative electrode active material is not particularly limited, as long as the purpose of the application can be achieved, for example, it can include but not limited to natural graphite, artificial graphite, mesophase micro carbon spheres, hard Carbon, soft carbon, silicon, silicon-carbon composite, Li-Sn alloy, Li-Sn-O alloy, Sn, SnO, SnO 2 , lithiated TiO 2 -Li 4 Ti 5 O 12 or Li with spinel structure
  • the negative electrode material layer may also include a conductive agent.
  • the present application has no special limitation on the conductive agent, as long as the purpose of the present application can be achieved, for example, it may include but not limited to at least one of the above-mentioned conductive agents.
  • the negative electrode material layer may also include a binder, and the present application has no special restrictions on the binder, as long as the purpose of the application can be achieved, for example, it may include but not limited to at least one of the above-mentioned binders .
  • the negative electrode may further include a conductive layer located between the negative electrode current collector and the negative electrode material layer.
  • the present application has no particular limitation on the composition of the conductive layer, which may be a commonly used conductive layer in the field, and the conductive layer may include but not limited to the above-mentioned conductive agent and the above-mentioned binder.
  • This application has no special restrictions on the separator, as long as the purpose of this application can be achieved, for example, it can include but not limited to polyethylene (PE), polypropylene (PP), polytetrafluoroethylene-based polyolefin (PO) separators , polyester film (such as polyethylene terephthalate (PET) film), cellulose film, polyimide film (PI), polyamide film (PA), spandex, aramid film, woven film, non At least one of woven film (non-woven fabric), microporous film, composite film, separator paper, laminated film or spun film, preferably PE.
  • PET polyethylene terephthalate
  • PI polyimide film
  • PA polyamide film
  • aramid film woven film
  • woven film non At least one of woven film (non-woven fabric), microporous film, composite film, separator paper, laminated film or spun film, preferably PE.
  • the separator of the present application may have a porous structure, and the pore size is not particularly limited as long as the purpose of the present application can be achieved, for example, the pore size may be 0.01 ⁇ m to 1 ⁇ m.
  • the thickness of the isolation film is not particularly limited, as long as the purpose of the present application can be achieved, for example, the thickness may be 5 ⁇ m to 500 ⁇ m.
  • a separator may include a substrate layer and a surface treatment layer.
  • the substrate layer can be a non-woven fabric, film or composite film with a porous structure, and the material of the substrate layer can include but not limited to polyethylene, polypropylene, polyethylene terephthalate or polyimide at least one.
  • a polypropylene porous film, a polyethylene porous film, a polypropylene non-woven fabric, a polyethylene non-woven fabric, or a polypropylene-polyethylene-polypropylene porous composite film may be used.
  • at least one surface of the substrate layer is provided with a surface treatment layer, and the surface treatment layer may be a polymer layer or an inorganic layer, or a layer formed by mixing a polymer and an inorganic material.
  • the inorganic material layer may include but not limited to inorganic particles and inorganic material layer binder, and the present application has no special limitation on inorganic particles, for example, may include but not limited to aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, hafnium dioxide, At least one of tin oxide, cerium oxide, nickel oxide, zinc oxide, calcium oxide, zirconium oxide, yttrium oxide, silicon carbide, boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide or barium sulfate.
  • the present application has no particular limitation on the inorganic layer binder, for example, it may include but not limited to polyvinylidene fluoride, copolymer of vinylidene fluoride-hexafluoropropylene, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, At least one of polyacrylate, polyvinylpyrrolidone, polyvinyl ether, polymethylmethacrylate, polytetrafluoroethylene or polyhexafluoropropylene.
  • polyvinylidene fluoride copolymer of vinylidene fluoride-hexafluoropropylene
  • polyamide polyacrylonitrile
  • polyacrylate polyacrylic acid
  • the polymer layer contains a polymer, and the polymer material may include but not limited to polyamide, polyacrylonitrile, acrylate polymer, polyacrylic acid, polyacrylate, polyvinyl pyrrolidone, polyvinyl ether, polyvinylidene fluoride At least one of ethylene or poly(vinylidene fluoride-hexafluoropropylene).
  • the electrolyte solution may also include a non-aqueous solvent, and the present application has no special limitation on the non-aqueous solvent, as long as the purpose of the application can be achieved, for example, it may include but not limited to carbonate compounds, carboxylate compounds, ether Compound or at least one of other organic solvents.
  • the above-mentioned carbonate compound may include but not limited to at least one of chain carbonate compound, cyclic carbonate compound or fluorocarbonate compound.
  • Chain carbonate compound can include but not limited to dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethylene propyl carbonate (EPC) or at least one of methyl ethyl carbonate (MEC).
  • the above-mentioned cyclic carbonate may include but not limited to at least one of ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC) or vinylethylene carbonate (VEC).
  • Fluorocarbonate compounds may include, but are not limited to, fluoroethylene carbonate (FEC), 1,2-difluoroethylene carbonate, 1,1-difluoroethylene carbonate, 1,1,2-trifluoroethylene carbonate Ethylene carbonate, 1,1,2,2-tetrafluoroethylene carbonate, 1-fluoro-2-methylethylene carbonate, 1-fluoro-1-methylethylene carbonate, 1,2- At least one of difluoro-1-methylethylene carbonate, 1,1,2-trifluoro-2-methylethylene carbonate, or trifluoromethylethylene carbonate.
  • FEC fluoroethylene carbonate
  • 1,2-difluoroethylene carbonate 1,1-difluoroethylene carbonate
  • 1,1,2,2-tetrafluoroethylene carbonate 1,1,2,2-tetrafluoroethylene carbonate
  • 1-fluoro-2-methylethylene carbonate 1-fluoro-1-methylethylene carbonate
  • carboxylate compounds may include but are not limited to methyl formate, methyl acetate, ethyl acetate, n-propyl acetate, tert-butyl acetate, methyl propionate, ethyl propionate, propyl propionate, ⁇ -butyl At least one of lactone, decanolactone, valerolactone, mevalonolactone or caprolactone.
  • the aforementioned ether compounds may include, but are not limited to, dibutyl ether, tetraglyme, diglyme, 1,2-dimethoxyethane, 1,2-diethoxyethane, ethoxy At least one of methoxyethane, 2-methyltetrahydrofuran or tetrahydrofuran.
  • the above-mentioned other organic solvents may include but not limited to dimethyl sulfoxide, 1,2-dioxolane, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, N-methyl-2- At least one of pyrrolidone, formamide, dimethylformamide, acetonitrile, trimethyl phosphate, triethyl phosphate, trioctyl phosphate or phosphoric acid ester.
  • the electrochemical device of the present application is not particularly limited, and it may include any device that undergoes an electrochemical reaction.
  • the electrochemical device may include, but is not limited to, a lithium metal secondary battery, a lithium ion secondary battery (lithium ion battery), a lithium polymer secondary battery, or a lithium ion polymer secondary battery, among others.
  • the preparation process of electrochemical devices is well known to those skilled in the art, and the present application is not particularly limited.
  • it may include but not limited to the following steps: stack the positive electrode, separator and negative electrode in sequence, and wind it as needed , folding and other operations to obtain the electrode assembly with a winding structure, put the electrode assembly into the packaging bag, inject the electrolyte into the packaging bag and seal it, and obtain an electrochemical device; or stack the positive electrode, separator and negative electrode in order, and then use Tape is used to fix the four corners of the entire laminated structure to obtain an electrode assembly with a laminated structure.
  • the electrode assembly is placed in a packaging bag, and the electrolyte is injected into the packaging bag and sealed to obtain an electrochemical device.
  • overcurrent prevention elements, guide plates, etc. can also be placed in the packaging bag as needed, so as to prevent pressure rise and overcharge and discharge inside the electrochemical device.
  • the third aspect of the present application provides an electronic device, comprising the electrochemical device in any of the foregoing embodiments of the present application.
  • the electrochemical device provided by the application has good cycle performance and safety performance, so the electronic device provided by the application has a long service life and good safety performance.
  • the electronic device of the present application is not particularly limited, and it may be used in any electronic device known in the prior art.
  • electronic devices may include, but are not limited to, notebook computers, pen-based computers, mobile computers, e-book players, cellular phones, portable fax machines, portable copiers, portable printers, headsets, VCRs, LCD TVs, portable cleaners, portable CD players, mini discs, transceivers, electronic organizers, calculators, memory cards, portable tape recorders, radios, backup power supplies, motors, cars, motorcycles, power-assisted bicycles, bicycles, Lighting appliances, toys, game consoles, clocks, electric tools, flashlights, cameras, large household storage batteries and lithium-ion capacitors, etc.
  • Thickness expansion rate after 400 cycles at 45°C (thickness of lithium ion battery after cycle - thickness of lithium ion battery before cycle) / thickness of lithium ion battery before cycle ⁇ 100%.
  • Hot box (Hot-box) test
  • Li-ion battery At 25°C, charge the Li-ion battery at a constant current of 0.7C to 4.5V, and at a constant voltage of 4.5V to a current of 0.05C. Place the lithium-ion battery in a high-temperature box and heat it to 135°C with a temperature rise rate of 5 ⁇ 2°C/min, for the 135°C Hot-box test, (heat to 137°C with a temperature rise rate of 5 ⁇ 2°C/min It is 137°C Hot-box test), and then keep it for 1 hour, and record the voltage, temperature and temperature of the lithium-ion battery and the change of the temperature of the hot box. Lithium-ion batteries pass the test if they do not catch fire, explode, or emit smoke. Each example or comparative example tests 10 lithium-ion batteries, and records the number of lithium-ion batteries that pass the test.
  • the lithium-ion battery in a constant temperature box at 25°C for 1 hour to make the lithium-ion battery reach a constant temperature; charge it with a constant current of 0.5C to 4.2V, then charge it with a constant current of 0.3C to 4.5V, and charge it at a constant voltage of 4.5V to the current 0.02C, let it stand for 30 minutes; then discharge it to 3.4V with a constant current of 0.1C, and let it stand for 30 minutes.
  • the capacity at this step is used as a benchmark.
  • the separator is obtained by disassembling the lithium-ion battery, and the separator is stacked along the length direction to obtain a three-layer separator with edges aligned in the length direction. Take a die with a size of 72.5mm ⁇ 54.2mm, where the edge of the die with a length of 72.5mm is placed parallel to the length direction of the separator, and punch out with a punching machine to obtain three samples of the separator.
  • the dimension X1 in the width direction (TD direction) and the dimension Z1 in the length direction (MD direction) of the separator sample were measured.
  • the isolation film samples in the way of a white paper for each sheet (the size of the white paper is A6, 105mm ⁇ 148mm), put the laminated isolation film samples into the steel plate, set the oven temperature to 135°C, and the oven reaches the set temperature. After temperature, put the diaphragm together with the steel plate into the oven and bake for 1 hour. After the baking, take out the sample and let it stand at room temperature for 10 minutes. Measure the lengthwise and widthwise dimensions of the same numbered diaphragm after baking, record the average dimension of each sample in the widthwise direction as X2, and record the average dimension of each sample in the longitudinal direction as Z2. If the edge of the sample shrinks unevenly, the maximum shrinkage position shall prevail.
  • shrinkage rate (size before baking - size after baking) / size before baking ⁇ 100%
  • TD heat shrinkage rate (X1-X2)/X1 ⁇ 100%
  • MD heat shrinkage rate (Z1-Z2)/Z1 ⁇ 100%.
  • FIG. 1 it is the Raman spectrogram of the positive electrode obtained by dismantling the lithium-ion battery in Example 1-4 and Comparative Example 1-1 through 400 cycles (cls) .
  • NMP N-methylpyrrolidone
  • the positive electrode slurry was uniformly coated on one surface of a positive electrode current collector aluminum foil with a thickness of 12 ⁇ m, and the aluminum foil was dried at 120° C. for 1 hour to obtain a positive electrode coated with a positive electrode material layer on one side.
  • Negative electrode active material artificial graphite, conductive agent acetylene black, binder styrene-butadiene rubber (SBR), thickener sodium carboxymethyl cellulose (CMC) are mixed according to the mass ratio of 95:2:2:1, add to Ionized water is used to obtain negative electrode slurry under the action of a vacuum mixer, wherein the solid content of the negative electrode slurry is 75%.
  • the negative electrode slurry was uniformly coated on one surface of the negative electrode current collector copper foil with a thickness of 12 ⁇ m, and the copper foil was dried at 120° C. to obtain a negative electrode with a coating thickness of 130 ⁇ m coated with a negative electrode material layer on one side.
  • ethylene carbonate, diethyl carbonate, and propyl propionate were prepared as a base solvent in a mass ratio of 3:4:3, and then lithium salt lithium hexafluorophosphate was added to the base solvent (LiPF 6 ) and compound I-1 represented by formula (I) to obtain an electrolyte solution.
  • LiPF 6 lithium salt lithium hexafluorophosphate
  • compound I-1 represented by formula (I)
  • the balance is the base solvent.
  • a porous PE film (provided by Celgard) with a thickness of 7 ⁇ m was used.
  • the positive electrode, separator and negative electrode prepared above are stacked in order, so that the separator is placed between the positive electrode and the negative electrode to play the role of isolation, and the electrode assembly is obtained by winding.
  • Put the electrode assembly in an aluminum-plastic film packaging bag inject electrolyte after drying, and obtain a lithium-ion battery through processes such as vacuum packaging, standing, chemical formation, degassing, and edge trimming.
  • the formation upper limit voltage is 4.15V
  • the formation temperature is 70°C
  • the formation resting time is 2h.
  • Example 1-2 to Example 1-13 except that relevant preparation parameters are adjusted according to Table 1, the rest are the same as Example 1-1.
  • Example 2-1 to Example 2-7 except that in ⁇ Preparation of Electrolyte>, cyclic sulfonic acid ester is also added and related preparation parameters are adjusted according to Table 2, the rest are the same as Example 1-4.
  • Example 3-1 to Example 3-12 except that in ⁇ Preparation of Electrolyte>, the compound represented by formula (III) is also added and the relevant preparation parameters are adjusted according to Table 3, the rest are the same as in Example 1-4 .
  • Example 4-1 to Example 4-11 except that in ⁇ Preparation of Electrolyte>, a cyano-containing compound was added and relevant preparation parameters were adjusted according to Table 4, the rest were the same as Example 1-4.
  • Example 5-1 to Example 5-4 in addition to ⁇ Preparation of Electrolyte>, according to Table 5, optional addition of cyclic sulfonic acid ester, compound represented by formula (III), and cyano group-containing compound , all the other are identical with embodiment 1-4.
  • Example 6-1 to Example 6-7 except that the relevant preparation parameters are adjusted according to Table 6, the rest are the same as Example 1-4.
  • Example 1-1 In Comparative Example 1-1 to Comparative Example 1-3, except that the relevant preparation parameters are adjusted according to Table 1, the rest are the same as Example 1-1.
  • Example 1-1 to Example 1-13, Comparative Example 1-1 to Comparative Example 1-3 are shown in Table 1; the relevant preparation parameters of Example 2-1 to Example 2-7 and performance tests are shown in Table 2; the relevant preparation parameters and performance tests of embodiment 3-1 to embodiment 3-12 are shown in table 3; the relevant preparation parameters and performance tests of embodiment 4-1 to embodiment 4-11 are shown in Table 2.
  • Table 4 the relevant preparation parameters and performance tests of embodiment 5-1 to embodiment 5-4 are shown in table 5; the relevant preparation parameters and performance tests of embodiment 6-1 to embodiment 6-7 are shown in table 6 .
  • Example 1-1 to Example 1-13 and Comparative Example 1-1 it can be seen that when the electrolyte includes the compound represented by formula (I), the cycle and safety performance of the lithium-ion battery can be improved.
  • the cycle and safety performance of the lithium-ion battery can be improved.
  • Can find out from embodiment 1-1 to embodiment 1-13, comparative example 1-2 and comparative example 1-3 when the mass percentage composition of the compound shown in formula (I) is in the scope of the present application, obtain Advanced lithium-ion batteries also have better cycle performance and safety performance.
  • Example 1-1 to Example 1-13 it can be seen that by selecting the compound represented by formula (I) within the scope of the present application, the obtained lithium ion battery has good cycle performance and safety performance at the same time.
  • Example 2-1 to Example 2-8 it can be seen that when the electrolyte includes a cyclic sulfonate on the basis of the compound shown in formula (I), the lithium ion can be further improved. Improve the cycle performance and storage performance of the battery, and reduce the impedance of the lithium-ion battery. From Example 2-1 to Example 2-7, it can be seen that when the cyclic sulfonic acid ester within the scope of the application is selected and the mass percentage of the cyclic sulfonic acid ester is controlled within the scope of the application, the obtained lithium ion The battery has both good cycle performance and storage performance, and low impedance.
  • Example 3-1 to Example 3-12 it can be seen that when the electrolyte includes the compound shown in formula (I) on the basis of including the compound shown in formula (III), it can further improve Cycle performance and safety performance of lithium-ion batteries. From Example 3-1 to Example 3-12, it can be seen that when the compound shown in the formula (III) within the scope of the application is selected, the mass percentage of the compound shown in the regulation formula (III), and the value of X/C are regulated Within the scope of the present application, the obtained lithium ion battery has good cycle performance and safety performance at the same time.
  • Example 4-1 to Example 4-11 it can be seen that when the electrolyte includes a cyano-containing compound on the basis of the compound shown in formula (I), the lithium-ion battery can be further improved. Cycle performance and storage performance.
  • the obtained lithium-ion battery has good cycle performance and storage performance at the same time.
  • Example 5-1 to Example 5-4 it can be seen that when the electrolyte includes the compound shown in formula (I), it also includes cyclic sulfonate, formula (III) At least two of the indicated compounds or cyano-containing compounds can further improve the cycle performance of lithium-ion batteries and reduce impedance. From Example 5-1 to Example 5-4, it can be seen that the compound shown in formula (I) has good compatibility with cyclic sulfonic acid esters, compounds shown in formula (III), and cyano-containing compounds, and can be used in combination The obtained lithium ion batteries all have good cycle performance and safety performance, as well as low impedance.
  • the mass percentage of lithium salt in the electrolyte, the type of lithium salt, and the thermal shrinkage rate of the separator usually affect the performance of lithium-ion batteries, such as cycle performance and safety performance. From Example 1-4, Example 6-1 to Example 6-7, it can be seen that when the mass percent content of the first lithium salt and the second lithium salt, the type of the first lithium salt and the second lithium salt, The heat shrinkage rate of the separator is within the scope of the present application, and the obtained lithium-ion battery has good cycle performance and safety performance.

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Abstract

本申请提供了一种电解液、包含该电解液的电化学装置及电子装置，电解液包括式(I)所示化合物，且式(I)所示化合物的质量百分含量X为0.05％至3％，有利于在正极表面形成稳定的正极电解质界面，在负极表面形成稳定的固态电解质界面，从而，在电化学装置循环过程中，有利于减少电解液中的溶剂和添加剂的损耗，降低正极和负极的产热量；以及减少对正极活性材料结晶结构的影响，进而减少正极活性材料颗粒的破碎、缓解过渡金属的溶出现象，提高电化学装置的循环性能和安全性能。

Description

一种电解液、包含该电解液的电化学装置及电子装置 技术领域
本申请涉及电化学技术领域，具体涉及一种电解液、包含该电解液的电化学装置及电子装置。
背景技术
锂离子电池具有储能密度大、开路电压高、自放电率低、循环寿命长、安全性好等优点，现已作为电源广泛应用于相机、手机、无人机、笔记本电脑和智能手表等电子产品。
随着锂离子电池的使用范围不断扩大，市场对锂离子电池提出了更高的要求，例如要求锂离子电池具有更长的寿命和更高的安全性能。因此，有鉴于此，开发一种合适的电解液成为本领域技术人员亟待解决的技术问题。
发明内容
本申请的目的在于提供一种电解液、包含该电解液的电化学装置及电子装置，以改善电化学装置的循环性能以及安全性能。
本申请的第一方面提供了一种电解液，其包括式(I)所示化合物，基于电解液的质量，式(I)所示化合物的质量百分含量X为0.05％至3％：
Figure PCTCN2021127986-appb-000001
其中，R 1和R 2各自独立地选自H、F、C 1至C 5的烷基、C 1至C 5的烷氧基或C 2至C 5的烯基、C 2至C 5的炔基；R选自O或-CH(R 3)-，R 3选自H、F、C 1至C 5的烷基、或C 1至C 5的烷氧基；Rb选自H、F、C 1至C 5的烷基、或C 1至C 5的烷氧基；A和B各自独立地选自-CO-或-SO 2-；W选自CH 2或O；M -选自基团M1至M3中的一种：
Figure PCTCN2021127986-appb-000002
电解液包括式(I)所示化合物，且式(I)所示化合物的质量百分含量X为0.05％至3％，有利于在正极表面形成稳定的正极电解质界面(CEI)，在负极表面形成稳定的固态电解质界面(SEI)，能够减少电解液与正极活性材料或负极活性材料之间的副反应，提高电化学装置的循环性能和安全性能。
在本申请的一些实施方案中，电解液包括下述化合物I-1至I-13中的至少一种：
Figure PCTCN2021127986-appb-000003
Figure PCTCN2021127986-appb-000004
在本申请的一些实施方案中，电解液还包括环状磺酸酯，环状磺酸酯包括环状单磺酸酯和/或环状二磺酸酯，基于电解液的质量，环状磺酸酯的质量百分含量为0.01％至10％；环状单磺酸酯包括1,3-丙烷磺酸内酯、1,2-丙烷磺酸内酯、1,4-丁烷磺酸内酯、1,2-丁烷磺酸内酯、1,3-丁烷磺酸内酯、2,4-丁烷磺酸内酯或1,3-戊烷磺酸内酯中的至少一种；环状二磺酸酯包括甲烷二磺酸亚甲酯和/或甲烷二磺酸亚乙酯。通过选择上述环状单磺酸酯，有利于提高电化学装置的循环性能和安全性能。通过选择上述环状磺酸酯并调控环状磺酸酯的质量百分含量在上述范围内，有利于提高电化学装置的循环性能和安全性能。
在本申请的一些实施方案中，电解液包括式(II)所示的化合物：
Figure PCTCN2021127986-appb-000005
其中，D和E各自独立地选自C 1至C 8的亚烷基或C 1至C 8的氟代亚烷基，L选自单键或-OSO 2-。
在本申请的一些实施方案中，电解液包括式(II-1)所示化合物和/或式(II-2)所示化合物：
Figure PCTCN2021127986-appb-000006
其中，R 6和R 7各自独立地选自H、F或C 1至C 4的烷基，n3为1、2、3或4；
Figure PCTCN2021127986-appb-000007
其中，D和E各自独立地选自C 1至C 8的亚烷基或C 1至C 8的氟代亚烷基。
在本申请的一些实施方案中，电解液还包括式(III)所示化合物，基于电解液的质量，式(III)所示化合物的质量百分含量C为0.5％至16％，且0.03≤X/C≤1：
Figure PCTCN2021127986-appb-000008
其中，R 12至R 15各自独立地选自H、F、C 1至C 10的氟代烷基、C 1至C 10的氟代烷氧基或C 1至C 10的氟代烷氧基烷基，且R 12至R 15不同时为H。
通过调控式(III)所示化合物的质量百分含量C在上述范围内，有利于更好地提高电化学装置的循环性能、降低电化学装置的阻抗；通过调控X/C的值的在上述范围内，有利于式(I)所示化合物和式(III)所示化合物之间形成协同作用，以提高电化学装置的循环性能和安全性能。
在本申请的一些实施方案中，电解液包括下述化合物III-1至III-6中的至少一种：
Figure PCTCN2021127986-appb-000009
在本申请的一些实施方案中，电解液还包括含氰基化合物，含氰基化合物包括式(IV) 至式(VII)所示化合物中的至少一种，基于电解液的质量，含氰基化合物的质量百分含量D为0.2％至10％：
Figure PCTCN2021127986-appb-000010
其中，R 16选自未取代或被Ra取代的C 1至C 12的亚烷基、未取代或被Ra取代的C 1至C 12的亚烷氧基；R 17和R 18各自独立地选自单键、未取代或被Ra取代的C 1至C 12的亚烷基、未取代或被Ra取代的C 1至C 12的亚烷氧基；R 19至R 21各自独立地选自单键、未取代或被Ra取代的C 1至C 12的亚烷基、未取代或被Ra取代的C 1至C 12的亚烷氧基、未取代或被Ra取代的C 1至C 12的亚烷氧基烷基；R 22和R 23各自独立地选自未取代或被Ra取代的C 1至C 12的亚烷基、未取代或被Ra取代的C 2至C 12的亚烯基、未取代或被Ra取代的C 6至C 26的亚芳基、未取代或被Ra取代的C 2至C 12的亚杂环基；R 24至R 27各自独立地选自未取代或被Ra取代的C 1至C 12的亚烷氧基烷基；各个基团的取代基Ra各自独立地选自卤素。
通过调控含氰基化合物的质量百分含量D在上述范围内，有利于更好地改善电化学装置的循环性能和高温性能。
在本申请的一些实施方案中，0.05≤X/D≤1。通过调控X/D的值在上述范围内，有利于式(I)所示化合物和含氰基化合物之间形成协同作用，以提高电化学装置的循环性能和安全性能。
在本申请的一些实施方案中，电解液包括下述化合物IV-1至IV-4、V-1至V-3、VI-1至VI-4、VII-1或VIII-1中的至少一种：
Figure PCTCN2021127986-appb-000011
在本申请的一些实施方案中，电解液满足以下条件中的至少一者：(i)电解液包括第一锂盐，第一锂盐包括六氟磷酸锂、双三氟甲烷磺酰亚胺锂、双(氟磺酰)亚胺锂或二氟草酸硼酸锂中的至少一种，基于电解液的质量，第一锂盐的质量百分含量Y为5％至13％；(ii)电解液包括第二锂盐，第二锂盐包括二氟磷酸锂和/或双草酸硼酸锂，基于电解液的质量，第二锂盐的质量百分含量Y1为0.05％至1％。通过选择上述第一锂盐和/或第二锂盐、调控第一锂盐和/或第二锂盐的质量百分含量在上述范围内，有利于第一锂盐和/或第二锂盐与电解液之间形成协同作用，从而改善电化学装置的循环性能和安全性能。
本申请的第二方面提供了一种电化学装置，包括正极和前述任一实施方案中的电解液，电化学装置经过至少400圈循环后，在拆解得到的正极的拉曼光谱图中，满足2≤R2/R1≤4，其中，R1为620cm -1至700cm -1之间最大的峰强度值，R2为500cm -1至600cm -1之间最大的峰强度值。
在本申请的一些实施方案中，电化学装置还包括负极，负极包括负极材料层，电化学 装置经过至少400圈循环后，基于负极材料层的质量，拆解得到的负极表面的Co的质量百分含量小于或等于0.12％。
在本申请的一些实施方案中，电化学装置满足以下条件中的至少一者：(iii)在升温速度为10℃/分的示差扫描热量测定(DSC)中，在140℃至163℃的范围内至少出现一个吸热峰；(iv)电化学装置还包括隔离膜，隔离膜在135℃下的热收缩率为2％至5％，其中，热收缩率包括宽度方向(TD方向)热收缩率和长度方向(MD方向)热收缩率。
本申请的第三方面提供了一种电子装置，包含本申请前述任一实施方案中的电化学装置。
本申请提供一种电解液、包含该电解液的电化学装置及电子装置，电解液包括式(I)所示化合物，且式(I)所示化合物的质量百分含量X为0.05％至3％，有利于在正极表面形成稳定的CEI，在负极表面形成稳定的SEI。这样，在电化学装置循环过程中，有利于减少电解液中的溶剂和添加剂的损耗，降低正极和负极的产热量；以及减少对正极活性材料结晶结构的影响，进而减少正极活性材料颗粒的破碎、缓解过渡金属的溶出现象，从而提高电化学装置的循环性能和安全性能。
附图说明
为了更清楚地说明本申请实施例和现有技术的技术方案，下面对实施例和现有技术中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请的一些实施例。
图1为本申请实施例1-4和对比例1-1中拆解得到的正极的拉曼光谱图。
具体实施方式
为使本申请的目的、技术方案、及优点更加清楚明白，以下参照附图和实施例，对本申请进一步详细说明。显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域普通技术人员所获得的所有其他技术方案，都属于本申请保护的范围。
需要说明的是，本申请的具体实施方式中，以锂离子电池作为电化学装置的例子来解释本申请，但是本申请的电化学装置并不仅限于锂离子电池。
本申请的第一方面提供了一种电解液，其包括式(I)所示化合物，基于电解液的质量， 式(I)所示化合物的质量百分含量X为0.05％至3％：
Figure PCTCN2021127986-appb-000012
其中，R 1和R 2各自独立地选自H、F、C 1至C 5的烷基、C 1至C 5的烷氧基或C 2至C 5的烯基、C 2至C 5的炔基；R选自O或-CH(R 3)-，R 3选自H、F、C 1至C 5的烷基、或C 1至C 5的烷氧基；Rb选自H、F、C 1至C 5的烷基、或C 1至C 5的烷氧基；A和B各自独立地选自-CO-或-SO 2-；W选自CH 2或O；M -选自基团M1至M3中的一种：
Figure PCTCN2021127986-appb-000013
例如，式(I)所示化合物的质量百分含量X可以为0.05％、0.1％、0.5％、1％、1.5％、2％、2.5％、3％或为其间的任意范围。不限于任何理论，本申请的发明人发现，电解液包括式(I)所示化合物，且式(I)所示化合物的质量百分含量X为0.05％至3％，有利于在正极表面形成稳定的CEI，在负极表面形成稳定的SEI，能够减少电解液与正极活性材料或负极活性材料之间的副反应。这样，在电化学装置循环过程中，有利于减少电解液中的溶剂和添加剂的损耗，降低正极和负极的产热量；以及减少对正极活性材料结晶结构的影响，进而减少正极活性材料颗粒的破碎、缓解过渡金属的溶出现象，从而提高电化学装置的循环性能和安全性能。
优选地，式(I)所示化合物为下述化合物I-1至I-13中的一种。在本申请的一些实施方案中，电解液包括下述化合物I-1至I-13中的至少一种：
Figure PCTCN2021127986-appb-000014
在本申请的一些实施方案中，电解液还包括环状磺酸酯，环状磺酸酯包括环状单磺酸酯和/或环状二磺酸酯，基于电解液的质量，环状磺酸酯的质量百分含量为0.01％至10％，优选为0.1％至5％；环状单磺酸酯包括1,3-丙烷磺酸内酯、1,2-丙烷磺酸内酯、1,4-丁烷磺酸内酯、1,2-丁烷磺酸内酯、1,3-丁烷磺酸内酯、2,4-丁烷磺酸内酯或1,3-戊烷磺酸内酯中的至少一种；环状二磺酸酯包括甲烷二磺酸亚甲酯和/或甲烷二磺酸亚乙酯。例如，环状磺酸酯的质量百分含量可以为0.01％、0.5％、1％、2％、3％、4％、5％、6％、7％、8％、9％、10％或为其间的任意范围。不限于任何理论，本申请的发明人发现，当环状磺酸酯的质量百分含量过低时(例如低于0.01％)，不能形成稳定的SEI和CEI，从而减少电解液与正极活性材 料和负极活性材料之间的副反应，则不能改善电化学装置的循环性能和安全性能。当环状磺酸酯的质量百分含量过高时(例如高于10％)，会SEI和CEI过厚或过于致密，影响锂离子的传输，从而影响电化学装置的动力学性能，例如阻抗和循环性能。通过选择上述环状磺酸酯并调控环状磺酸酯的质量百分含量在上述范围内，有利于提高电化学装置的循环性能和安全性能、降低阻抗。
在本申请的一些实施方案中，电解液包括式(II)所示的化合物：
Figure PCTCN2021127986-appb-000015
其中，D和E各自独立地选自C 1至C 8的亚烷基或C 1至C 8的氟代亚烷基，L选自单键或-OSO 2-。
在本申请的一些实施方案中，电解液包括式(II-1)所示化合物：
Figure PCTCN2021127986-appb-000016
其中，R 6和R 7各自独立地选自H、F或C 1至C 4的烷基，n3为1、2、3或4。式(II-1)所示化合物即为环状单磺酸酯，通过选择式(II-1)所示环状单磺酸酯，有利于提高电化学装置的循环性能和安全性能。
在本申请的一些实施方案中，电解液包括式(II-2)所示化合物：
Figure PCTCN2021127986-appb-000017
Figure PCTCN2021127986-appb-000018
其中，D和E各自独立地选自C 1至C 8的亚烷基或C 1至C 8的氟代亚烷基。式(II-2)所示化合物即为环状二磺酸酯，通过选择式(II-2)所示环状二磺酸酯，有利于提高电化学装置的循环性能和安全性能。
在本申请的一些实施方案中，电解液包括式(II-1)所示化合物和式(II-2)所示化合物，也即电解液包括环状单磺酸酯和环状二磺酸酯。当电解液同时包括环状单磺酸酯和环状二磺酸酯时，环状单磺酸酯和环状二磺酸酯两者的比例没有特别限制，只要能实现本申请的目的即可，例如，环状单磺酸酯和环状二磺酸酯的质量比为1:1。
在本申请的一些实施方案中，电解液还包括式(III)所示化合物，基于电解液的质量，式(III)所示化合物的质量百分含量C为0.5％至16％，且0.03≤X/C≤1，优选为0.03≤X/C≤0.2：
Figure PCTCN2021127986-appb-000019
其中，R 12至R 15各自独立地选自H、F、C 1至C 10的氟代烷基、C 1至C 10的氟代烷氧基或C 1至C 10的氟代烷氧基烷基，且R 12至R 15不同时为H。
优选地，式(III)所示化合物为下述化合物III-1至III-6中的一种。在本申请的一些实施方案中，电解液包括下述化合物III-1至III-6中的至少一种：
Figure PCTCN2021127986-appb-000020
例如，式(III)所示化合物的质量百分含量C可以为0.5％、1％、2％、5％、8％、10％、 12％、15％、16％或为其间的任意范围，X/C的值可以为0.03、0.05、0.1、0.2、0.3、0.5、0.8、1或为其间的任意范围。不限于任何理论，本申请的发明人发现，电解液中包括式(III)所示化合物，有利于提高SEI的稳定性，有利于减少电解液与负极活性材料之间的副反应，提高电化学装置的循环性能；以及，改善电化学装置循环过程中副反应产生的副产物积累，降低电化学装置的阻抗。但当式(III)所示化合物的质量百分含量C过高时(例如高于16％)，SEI过厚或过于致密，影响锂离子的传输，从而影响电化学装置的动力学性能，例如阻抗和循环性能。通过调控式(III)所示化合物的质量百分含量C在上述范围内，有利于更好地提高电化学装置的循环性能、降低电化学装置的阻抗；通过调控X/C的值的在上述范围内，有利于式(I)所示化合物和式(III)所示化合物之间形成协同作用，以提高电化学装置的循环性能和安全性能。
在本申请的一些实施方案中，电解液还包括含氰基化合物，含氰基化合物包括式(IV)至式(VII)所示化合物中的至少一种，基于电解液的质量，含氰基化合物的质量百分含量D为0.2％至10％：
Figure PCTCN2021127986-appb-000021
其中，R 16选自未取代或被Ra取代的C 1至C 12的亚烷基、未取代或被Ra取代的C 1至C 12的亚烷氧基；R 17和R 18各自独立地选自单键、未取代或被Ra取代的C 1至C 12的亚烷基、未取代或被Ra取代的C 1至C 12的亚烷氧基；R 19至R 21各自独立地选自单键、未取代或被Ra取代的 C 1至C 12的亚烷基、未取代或被Ra取代的C 1至C 12的亚烷氧基、未取代或被Ra取代的C 1至C 12的亚烷氧基烷基；R 22和R 23各自独立地选自未取代或被Ra取代的C 1至C 12的亚烷基、未取代或被Ra取代的C 2至C 12的亚烯基、未取代或被Ra取代的C 6至C 26的亚芳基、未取代或被Ra取代的C 2至C 12的亚杂环基；R 24至R 27各自独立地选自未取代或被Ra取代的C 1至C 12的亚烷氧基烷基；各个基团的取代基Ra各自独立地选自卤素。
优选地，式(IV)所示化合物为下述化合物IV-1至IV-4中的一种，式(V)所示化合物为下述化合物V-1至V-3中的一种，式(VI)所示化合物为下述化合物VI-1至VI-4中的一种，式(VII)所示化合物为VII-1，式(VIII)所示化合物为VIII-1。
在本申请的一些实施方案中，电解液包括下述化合物IV-1至IV-4、V-1至V-3、VI-1至VI-4、VII-1或VIII-1中的至少一种：
Figure PCTCN2021127986-appb-000022
例如，含氰基化合物的质量百分含量D为0.2％、0.5％、1％、2％、3％、4％、5％、6％、7％、8％、9％、10％或为其间的任意范围。不限于任何理论，本申请的发明人发现，含氰基化合物中氰基中的孤对电子的能级与正极活性材料中过渡金属原子最外层的空余轨道的能级接近，从而含氰基化合物可以在正极表面与正极活性材料形成络合结构，能够减少 电解液与正极活性材料之间的副反应，有利于改善电化学装置的循环性能和高温存储性能。但当含氰基化合物的质量百分含量D过高时(例如高于10％)，含氰基化合物与正极活性材料形成络合结构过多，影响锂离子的传输，从而影响电化学装置的动力学性能，例如阻抗和循环性能。通过调控含氰基化合物的质量百分含量D在上述范围内，有利于更好地改善电化学装置的循环性能和高温性能。
在本申请的一些实施方案中，0.05≤X/D≤1。例如，X/D的值可以为0.05、0.1、0.2、0.3、0.4、0.5、0.6、0.7、0.8、0.9、1或为其间的任意范围。通过调控X/D的值在上述范围内，有利于式(I)所示化合物和含氰基化合物之间形成协同作用，以提高电化学装置的循环性能和安全性能。
在本申请的一些实施方案中，电解液还包括锂盐，锂盐中包括氟元素、硼元素或磷元素中的至少一种。不限于任何理论，本申请的发明人发现，锂盐中包含上述元素，有利于锂盐与电解液之间形成协同作用，从而改善电化学装置的循环性能和安全性能。
在本申请的一些实施方案中，电解液满足以下条件中的至少一者：(i)电解液中包括第一锂盐，第一锂盐包括六氟磷酸锂、双三氟甲烷磺酰亚胺锂、双(氟磺酰)亚胺锂或二氟草酸硼酸锂中的至少一种，基于电解液的质量，锂盐的质量百分含量Y为5％至13％；(ii)电解液中包括第二锂盐，第二锂盐包括二氟磷酸锂和/或双草酸硼酸锂，基于电解液的质量，二氟磷酸锂和/或双草酸硼酸锂的质量百分含量Y1为0.05％至1％。
例如，第一锂盐的质量百分含量Y可以为5％、8％、10％、13％或为其间的任意范围。通过选择上述第一锂盐，有利于第一锂盐与电解液之间形成协同作用，从而改善电化学装置的循环性能和安全性能。
例如，第二锂盐的质量百分含量Y1可以为0.05％、0.1％、0.2％、0.3％、0.4％、0.5％、0.6％、0.7％、0.8％、0.9％、1％或为其间的任意范围。通过选择上述第二锂盐，更有利于第二锂盐与电解液之间形成协同作用，从而改善电化学装置的循环性能和安全性能。
本申请的第二方面提供了一种电化学装置，包括正极和前述任一实施方案中的电解液，电化学装置经过至少400圈循环后，在拆解得到的正极的拉曼光谱图中，满足2≤R2/R1≤4，其中，R1为620cm -1至700cm -1之间最大的峰强度值，R2为500cm -1至600cm -1之间最大的峰强度值。例如，R2/R1的值可以为2、2.2、2.5、2.8、3、3.3、3.5、3.7、4或为其间的任意范 围。R2/R1的值在上述范围内，该正极在本申请提供的电解液中能够维持稳定的晶体结构，进一步提高电化学装置的循环性能。
在本申请的一些实施方案中，电化学装置还包括负极，负极包括负极材料层，电化学装置经过至少400圈循环后，基于负极材料层的质量，拆解得到的负极表面的Co的质量百分含量小于或等于0.12％，说明本申请提供的电解液有效抑制了正极材料中钴元素的溶出，能够有效改善电化学装置的循环性能。
在本申请的一些实施方案中，电化学装置满足以下条件中的至少一者：(iii)在升温速度为10℃/分的示差扫描热量测定(DSC)中，在140℃至163℃的范围内至少出现一个吸热峰；(iv)电化学装置还包括隔离膜，隔离膜在135℃下的热收缩率为2％至5％。
例如，在正极的DSC曲线中，吸热峰对应的温度可以为140℃、145℃、150℃、155℃、160℃、163℃或为其间的任意范围。说明正极具有良好的热稳定性。
例如，隔离膜在135℃下的热收缩率可以为2％、2.5％、3％、3.5％、4％、4.5％、5％或为其间的任意范围。说明隔离膜具有良好的热稳定性，从而有利于改善电化学装置的安全性能。
正极通常包括正极集流体和正极材料层，在本申请中，正极集流体没有特别限制，只要能够实现本申请目的即可，例如可以包括但不限于铝箔、铝合金箔或复合集流体等。在本申请中，对正极集流体的厚度没有特别限制，只要能够实现本申请目的即可，例如厚度为8μm至12μm。在本申请中，正极材料层可以设置于正极集流体厚度方向上的一个表面上，也可以设置于正极集流体厚度方向上的两个表面上。需要说明，这里的“表面”可以是正极集流体的全部区域，也可以是正极集流体的部分区域，本申请没有特别限制，只要能实现本申请目的即可。
在本申请中，正极材料层中包括正极活性材料，本申请对正极活性材料没有特别限制，只要能够实现本申请目的即可，例如可以包括锂或过渡金属元素的复合氧化物中的至少一种。本申请对上述过渡金属元素没有特别限制，只要能实现本申请的目的即可，例如可以包括镍、锰、钴或铁中的至少一种。具体的，正极活性材料可以包括镍钴锰酸锂(811、622、523、111)、镍钴铝酸锂、磷酸铁锂、富锂锰基材料、钴酸锂、锰酸锂、磷酸锰铁锂或钛酸锂中的至少一种。
正极材料层还可以包括粘结剂，本申请对粘结剂没有特别限制，只要能够实现本申请目的即可，例如可以包括但不限于聚丙烯酸、聚丙烯酸钠、聚丙烯酸钾、聚丙烯酸锂、聚酰亚胺、聚乙烯醇、羧甲基纤维素、羧甲基纤维素钠、聚酰亚胺、聚酰胺酰亚胺、丁苯橡胶或聚偏氟乙烯中的至少一种。
在本申请中，正极材料层中还可以包括导电剂，本申请对导电剂没有特别限制，只要能够实现本申请目的即可，例如可以包括但不限于导电炭黑(Super P)、碳纳米管(CNTs)、碳纤维、鳞片石墨、科琴黑、石墨烯、金属材料或导电聚合物中的至少一种。上述碳纳米管可以包括但不限于单壁碳纳米管和/或多壁碳纳米管。上述碳纤维可以包括但不限于气相生长碳纤维(VGCF)和/或纳米碳纤维。上述金属材料可以包括但不限于金属粉和/或金属纤维，具体地，金属可以包括但不限于铜、镍、铝或银中的至少一种。上述导电聚合物可以包括但不限于聚亚苯基衍生物、聚苯胺、聚噻吩、聚乙炔或聚吡咯中的至少一种。
任选地，正极还可以包括导电层，导电层位于正极集流体和正极材料层之间。本申请对导电层的组成没有特别限制，可以是本领域常用的导电层，例如可以包括但不限于上述导电剂和上述粘结剂。
负极通常包括负极集流体，本申请对负极集流体没有特别限制，只要能够实现本申请目的即可，例如，可以包括但不限于铜箔、铜合金箔、镍箔、不锈钢箔、钛箔、泡沫镍、泡沫铜或复合集流体等。在本申请中，对负极的集流体的厚度没有特别限制，只要能够实现本申请目的即可，例如厚度为4μm至12μm。在本申请中，负极材料层可以设置于负极集流体厚度方向上的一个表面上，也可以设置于负极集流体厚度方向上的两个表面上。需要说明，这里的“表面”可以是负极集流体的全部区域，也可以是负极集流体的部分区域，本申请没有特别限制，只要能实现本申请目的即可。
本申请中，负极材料层包括负极活性材料，其中，负极活性材料没有特别限制，只要能实现本申请的目的即可，例如可以包括但不限于天然石墨、人造石墨、中间相微碳球、硬碳、软碳、硅、硅-碳复合物、Li-Sn合金、Li-Sn-O合金、Sn、SnO、SnO 2、尖晶石结构的锂化TiO 2-Li 4Ti 5O 12或Li-Al合金中的至少一种。
在本申请中，负极材料层中还可以包括导电剂，本申请对导电剂没有特别限制，只要能够实现本申请目的即可，例如可以包括但不限于上述导电剂中的至少一种。
在本申请中，负极材料层中还可以包括粘结剂，本申请对粘结剂没有特别限制，只要能够实现本申请目的即可，例如可以包括但不限于上述粘结剂中的至少一种。
任选地，负极还可以包括导电层，导电层位于负极集流体和负极材料层之间。本申请对导电层的组成没有特别限制，可以是本领域常用的导电层，导电层可以包括但不限于上述导电剂和上述粘结剂。
本申请对隔离膜没有特别限制，只要能够实现本申请目的即可，例如可以包括但不限于聚乙烯(PE)、聚丙烯(PP)、聚四氟乙烯为主的聚烯烃(PO)类隔膜、聚酯膜(例如聚对苯二甲酸二乙酯(PET)膜)、纤维素膜、聚酰亚胺膜(PI)、聚酰胺膜(PA)、氨纶、芳纶膜、织造膜、非织造膜(无纺布)、微孔膜、复合膜、隔膜纸、碾压膜或纺丝膜中的至少一种，优选为PE。本申请的隔离膜可以具有多孔结构，孔径的尺寸没有特别限制，只要能实现本申请的目的即可，例如，孔径的尺寸可以为0.01μm至1μm。在本申请中，隔离膜的厚度没有特别限制，只要能实现本申请的目的即可，例如厚度可以为5μm至500μm。
例如，隔离膜可以包括基材层和表面处理层。基材层可以为具有多孔结构的无纺布、膜或复合膜，基材层的材料可以包括但不限于聚乙烯、聚丙烯、聚对苯二甲酸乙二醇酯或聚酰亚胺中的至少一种。任选地，可以使用聚丙烯多孔膜、聚乙烯多孔膜、聚丙烯无纺布、聚乙烯无纺布或聚丙烯-聚乙烯-聚丙烯多孔复合膜。任选地，基材层的至少一个表面上设置有表面处理层，表面处理层可以是聚合物层或无机物层，也可以是混合聚合物与无机物所形成的层。
无机物层可以包括但不限于无机颗粒和无机物层粘结剂，本申请对无机颗粒没有特别限制，例如，可以包括但不限于氧化铝、氧化硅、氧化镁、氧化钛、二氧化铪、氧化锡、二氧化铈、氧化镍、氧化锌、氧化钙、氧化锆、氧化钇、碳化硅、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。本申请对无机物层粘结剂没有特别限制，例如，可以包括但不限于聚偏氟乙烯、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、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。聚合物层中包含聚合物，聚合物的材料可以包括但不限于聚酰胺、聚丙烯腈、丙烯酸酯聚合物、聚丙烯酸、聚丙烯酸盐、聚乙烯呲咯烷酮、聚乙烯醚、聚偏氟乙烯或聚(偏氟乙烯-六氟丙烯)中的至少一种。
在本申请中，电解液还可以包括非水溶剂，本申请对非水溶剂没有特别限制，只要能 实现本申请的目的即可，例如可以包括但不限于碳酸酯化合物、羧酸酯化合物、醚化合物或其它有机溶剂中的至少一种。上述碳酸酯化合物可以包括但不限于链状碳酸酯化合物、环状碳酸酯化合物或氟代碳酸酯化合物中的至少一种。上述链状碳酸酯化合物可以包括但不限于碳酸二甲酯(DMC)、碳酸二乙酯(DEC)、碳酸二丙酯(DPC)、碳酸甲丙酯(MPC)、碳酸乙丙酯(EPC)或碳酸甲乙酯(MEC)中的至少一种。上述环状碳酸酯可以包括但不限于碳酸乙烯酯(EC)、碳酸亚丙酯(PC)、碳酸亚丁酯(BC)或碳酸乙烯基亚乙酯(VEC)中的至少一种。氟代碳酸酯化合物可以包括但不限于氟代碳酸乙烯酯(FEC)、碳酸1,2-二氟亚乙酯、碳酸1,1-二氟亚乙酯、碳酸1,1,2-三氟亚乙酯、碳酸1,1,2,2-四氟亚乙酯、碳酸1-氟-2-甲基亚乙酯、碳酸1-氟-1-甲基亚乙酯、碳酸1,2-二氟-1-甲基亚乙酯、碳酸1,1,2-三氟-2-甲基亚乙酯或碳酸三氟甲基亚乙酯中的至少一种。上述羧酸酯化合物可以包括但不限于甲酸甲酯、乙酸甲酯、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、甲瓦龙酸内酯或己内酯中的至少一种。上述醚化合物可以包括但不限于二丁醚、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-甲基四氢呋喃或四氢呋喃中的至少一种。上述其它有机溶剂可以包括但不限于二甲亚砜、1,2-二氧戊环、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、磷酸三辛酯或磷酸酯中的至少一种。
本申请的电化学装置没有特别限制，其可以包括发生电化学反应的任何装置。在一些实施方案中，电化学装置可以包括但不限于：锂金属二次电池、锂离子二次电池(锂离子电池)、锂聚合物二次电池或锂离子聚合物二次电池等。
电化学装置的制备过程为本领域技术人员所熟知的，本申请没有特别的限制，例如，可以包括但不限于以下步骤：将正极、隔离膜和负极按顺序堆叠，并根据需要将其卷绕、折叠等操作得到卷绕结构的电极组件，将电极组件放入包装袋内，将电解液注入包装袋并封口，得到电化学装置；或者，将正极、隔离膜和负极按顺序堆叠，然后用胶带将整个叠片结构的四个角固定好得到叠片结构的电极组件，将电极组件置入包装袋内，将电解液注入包装袋并封口，得到电化学装置。此外，也可以根据需要将防过电流元件、导板等置于包装袋中，从而防止电化学装置内部的压力上升、过充放电。
本申请的第三方面提供了一种电子装置，包含本申请前述任一实施方案中的电化学装 置。本申请提供的电化学装置具有良好的循环性能和安全性能，从而本申请提供的电子装置具有较长的使用寿命和良好的安全性能。
本申请的电子装置没有特别限定，其可以是用于现有技术中已知的任何电子装置。在一些实施例中，电子装置可以包括，但不限于，笔记本电脑、笔输入型计算机、移动电脑、电子书播放器、便携式电话、便携式传真机、便携式复印机、便携式打印机、头戴式立体声耳机、录像机、液晶电视、手提式清洁器、便携CD机、迷你光盘、收发机、电子记事本、计算器、存储卡、便携式录音机、收音机、备用电源、电机、汽车、摩托车、助力自行车、自行车、照明器具、玩具、游戏机、钟表、电动工具、闪光灯、照相机、家庭用大型蓄电池和锂离子电容器等。
实施例
以下，举出实施例及对比例来对本申请的实施方式进行更具体地说明。各种的试验及评价按照下述的方法进行。另外，只要无特别说明，“份”、“％”为质量基准。
测试方法和设备：
80℃存储厚度膨胀率测试：
将锂离子电池在25℃下以0.5C恒流放电至3.0V，再以0.5C恒流充电至4.5V，4.5V下恒压充电至0.05C，用千分尺测试并记录锂离子电池的厚度记为H 11。放置到80℃烘箱当中，4.5V恒压7小时，7小时结束后用千分尺测试并记录电池的厚度，记为H 12。
80℃存储厚度膨胀率＝(H 12-H 11)/H 11×100％。
45℃高温循环测试：
将锂离子电池置于45℃恒温箱中，静置30分钟，使锂离子电池达到恒温。将达到恒温的锂离子电池在45℃下以0.2C恒流充电至4.5V，4.5V下恒压充电至0.05C，静置5分钟，再以0.2C恒流放电至3.0V，静置5分钟，测试初始容量；然后再以1.3C恒流充电至4.15V，以4.15V恒压充电至电流为1C；再以1C恒流充电至4.25V，然后以4.25V恒压充电至电流为0.8C；再以0.8C恒流充电至4.5V，然后以4.5V恒压充电至电流为0.05C；放置5分钟；接着以1C恒流放电至电压为3.0V，静置5分钟；此为一个充放电循环。如此充电/放电，计算锂离子电池循环400次后的容量保持率和厚度膨胀率。
45℃循环400圈后的容量保持率＝第400次循环的放电容量/第1次循环放电容量×100％。
45℃循环400圈后的厚度膨胀率＝(循环后的锂离子电池厚度-循环前的锂离子电池厚度)/循环前的锂离子电池厚度×100％。
热箱(Hot-box)测试：
在25℃下，将锂离子电池以0.7C恒流充电至4.5V，4.5V恒压充电至电流为0.05C。将锂离子电池放置在高温箱中，用5±2℃/分钟的温升速率加热到135℃，为135℃Hot-box测试，(用5±2℃/分钟的温升速率加热到137℃为137℃Hot-box测试)，然后保持1小时，记录锂离子电池的电压、温度以及热箱温度的变化。锂离子电池不起火、不爆炸、不冒烟即为通过测试。每个实施例或对比例测试10个锂离子电池，记录通过测试的锂离子电池的个数。
25℃直流阻抗(DCR)的测试：
将锂离子电池在25℃恒温箱中静置1小时，使锂离子电池达到恒温；以0.5C恒流充电至4.2V，再以0.3C恒流充电至4.5V，4.5V恒压充电至电流为0.02C，静置30分钟；再以0.1C恒流放电至3.4V，静置30分钟，此步容量作为基准。25℃条件下以0.5C恒流充电至4.2V,再以0.3C恒流充电至4.5V，4.5V恒压充电至电流为0.02C，静置30分钟；以0.1C恒流放电60分钟(容量以锂离子电池理论容量计算)，记录此时的电压为V1；再以1C恒流放电1s(容量以锂离子电池理论容量计算)，记录此时的电压为V2，计算电芯20％荷电状态(SOC)状态对应直流阻抗。20％SOC DCR＝(V1-V2)/1C。
热收缩率测试：
拆解锂离子电池得到隔离膜，将隔离膜沿长度方向进行层叠，得到长度方向上边缘对齐的三层隔离膜。取用72.5mm×54.2mm尺寸刀模，其中，刀模长度为72.5mm的边缘与隔离膜长度方向平行放置，采用冲压机冲切得到隔离膜样本三份。测量隔离膜样本宽度方向(TD方向)的尺寸X1，和长度方向(MD方向)的尺寸Z1。将隔离膜样本依每张间隔一张白纸的方式层叠(白纸尺寸为A6，105mm×148mm)，层叠好的隔离膜样本放入钢盘，将烘箱温度设置为135℃，烘箱达到设定温度后连同钢盘将隔膜入烘箱烘烤1h，烘烤结束后，取出样本，常温静置10min。分别测量相同编号隔膜烘烤后的长度方向和宽度方向的尺寸，宽度方向各样本的平均尺寸记录为X2，长度方向各样本的平均尺寸记录为Z2。若样本边缘收缩不均匀，则以收缩最大位置为准。
热收缩计算：收缩率＝(烘烤前尺寸-烘烤后尺寸)/烘烤前尺寸×100％
即：TD热收缩率＝(X1-X2)/X1×100％，
MD热收缩率＝(Z1-Z2)/Z1×100％。
拉曼光谱测试：
将锂离子电池经过400圈循环并满放后在手套箱(氩气环境)中拆解取出正极，将正极裁成3cm×3cm的极片，将裁切的极片用DMC冲洗多次然后晾干备用。将晾干后的极片裁切粘到平整的玻璃板上，用拉曼光谱仪(型号：HR Evolution)进行测试，并收集相关数据。
如图1所示，为实施例1-4和对比例1-1中的锂离子电池经过400圈(cls)循环，拆解得到的正极的拉曼光谱图，实施例1-4在620cm -1至700cm -1之间最大的峰强度值R1为59.29，在500cm -1至600cm -1之间最大的峰强度值R2为194.11，R2/R1＝3.27；对比例1-1在620cm -1至700cm -1之间最大的峰强度值R1为59.30，在500cm -1至600cm -1之间最大的峰强度值R2为96.92，R2/R1＝1.63。可见，实施例1-4的R2/R1的值在本申请的范围内，而对比例1-1的R2/R1的值不在本申请的范围内。
实施例1-1
<正极的制备>
将上述制备得到的正极活性材料钴酸锂、导电剂乙炔黑、粘结剂聚偏二氟乙烯按照质量比为96∶2∶2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至体系成均一透明状，获得正极浆料，其中正极浆料的固含量为70％。将正极浆料均匀涂覆于厚度为12μm的正极集流体铝箔的一个表面上，将铝箔在120℃下烘干处理1h，得到单面涂覆有正极材料层的正极。在铝箔的另一个表面上重复以上步骤，即得到双面涂布正极材料层的正极。然后经过冷压、裁片、分切后，在120℃的真空条件下干燥1h，得到规格为74mm×867mm的正极。
<负极的制备>
将负极活性材料人造石墨、导电剂乙炔黑、粘结剂丁苯橡胶(SBR)、增稠剂羧甲基纤维素钠(CMC)按照质量比为95∶2∶2∶1进行混合，加入去离子水，在真空搅拌机作用 下获得负极浆料，其中负极浆料的固含量为75％。将负极浆料均匀涂覆于厚度为12μm的负极集流体铜箔的一个表面上，将铜箔在120℃下烘干，得到涂层厚度为130μm的单面涂覆有负极材料层的负极。在铝箔的另一个表面上重复以上步骤，即得到双面涂布负极材料层的负极。然后经过冷压、裁片、分切后，在120℃的真空条件下干燥1h，得到规格为74mm×867mm的负极。
<电解液的制备>
在含水量<10ppm的氩气气氛手套箱中，将碳酸乙烯酯、碳酸二乙酯、丙酸丙酯按照质量比为3∶4∶3配制成基础溶剂，然后向基础溶剂中加入锂盐六氟磷酸锂(LiPF 6)和式(I)所示化合物I-1，得到电解液。基于电解液的质量，LiPF 6的质量百分含量为12％，式(I)所示化合物的质量百分含量为0.01％，余量为基础溶剂。
<隔离膜的制备>
采用厚度为7μm的多孔PE薄膜(Celgard公司提供)。
<锂离子电池的制备>
将上述制备得到的正极、隔离膜、负极按顺序叠好，使隔离膜处于正极和负极中间已起到隔离的作用，卷绕得到电极组件。将电极组件置于铝塑膜包装袋中，干燥后注入电解液，经过真空封装、静置、化成、脱气、切边等工序得到锂离子电池。化成上限电压为4.15V，化成温度为70℃，化成静置时间为2h。
实施例1-2至实施例1-13中，除了按照表1调整相关制备参数以外，其余与实施例1-1相同。
实施例2-1至实施例2-7中，除了在<电解液的制备>中，还加入环状磺酸酯并按照表2调整相关制备参数以外，其余与实施例1-4相同。
实施例3-1至实施例3-12中，除了在<电解液的制备>中，还加入式(III)所示化合物并按照表3调整相关制备参数以外，其余与实施例1-4相同。
实施例4-1至实施例4-11中，除了在<电解液的制备>中，还加入含氰基化合物并按照表4调整相关制备参数以外，其余与实施例1-4相同。
实施例5-1至实施例5-4中，除了在<电解液的制备>中，还按照表5可选第加入环状 磺酸酯、式(III)所示化合物、含氰基化合物以外，其余与实施例1-4相同。
实施例6-1至实施例6-7中，除了按照表6调整相关制备参数以外，其余与实施例1-4相同。
对比例1-1至对比例1-3中，除了按照表1调整相关制备参数以外，其余与实施例1-1相同。
实施例1-1至实施例1-13、对比例1-1至对比例1-3的相关制备参数及性能测试如表1所示；实施例2-1至实施例2-7相关制备参数及性能测试如表2所示；实施例3-1至实施例3-12相关制备参数及性能测试如表3所示；实施例4-1至实施例4-11相关制备参数及性能测试如表4所示；实施例5-1至实施例5-4相关制备参数及性能测试如表5所示；实施例6-1至实施例6-7相关制备参数及性能测试如表6所示。
表1
Figure PCTCN2021127986-appb-000023
注：表1中的“/”表示不存在对应制备参数或物质。
从实施例1-1至实施例1-13、对比例1-1可以看出，当电解液中包括式(I)所示化合物，能够提高锂离子电池的循环和安全性能。从实施例1-1至实施例1-13、对比例1-2和对比例1-3可以看出，当式(I)所示化合物的质量百分含量在本申请的范围内时，得到的锂离子电池同时具有更好的循环性能和安全性能。从实施例1-1至实施例1-13可以看出，选择本申请范围内的式(I)所示化合物，得到的锂离子电池同时具有良好的循环性能和安全性能。
表2
Figure PCTCN2021127986-appb-000024
注：表2中的“/”表示不存在对应制备参数或物质。
从实施例1-4、实施例2-1至实施例2-8可以看出，当电解液在包括式(I)所示化合物基础上，还包括环状磺酸酯，可以进一步提高锂离子电池的循环性能和存储性能、降低锂离子电池的阻抗。从实施例2-1至实施例2-7可以看出，当选择本申请范围内的环状磺酸酯、调控环状磺酸酯的质量百分含量在本申请范围内，得到的锂离子电池同时具有良好的循环性能和存储性能、以及较低的阻抗。
表3
Figure PCTCN2021127986-appb-000025
Figure PCTCN2021127986-appb-000026
注：表3中的实施例中的X＝0.5％，表3中的“/”表示不存在对应制备参数或物质。
从实施例1-4、实施例3-1至实施例3-12可以看出，当电解液在包括式(I)所示化合物基础上，还包括式(III)所示化合物，可以进一步提高锂离子电池的循环性能和安全性能。实施例3-1至实施例3-12可以看出，当选择本申请范围内的式(III)所示化合物、调控式(III)所示化合物的质量百分含量、调控X/C的值在本申请范围内，得到的锂离子电池同时具有良好的循环性能和安全性能。
表4
Figure PCTCN2021127986-appb-000027
Figure PCTCN2021127986-appb-000028
注：表4中的实施例中的X＝0.5％，表4中的“/”表示不存在对应制备参数或物质。
从实施例1-4、实施例4-1至实施例4-11可以看出，当电解液在包括式(I)所示化合物基础上，还包括含氰基化合物，可以进一步提高锂离子电池循环性能和存储性能。从实施例4-1至实施例4-11可以看出，当选择本申请范围内的含氰基化合物、调控含氰基化合物的质量百分含量、调控X/D的值在本申请范围内，得到的锂离子电池同时具有良好的循环性能和存储性能。
表5
Figure PCTCN2021127986-appb-000029
注：表5中的“/”表示不存在对应制备参数或物质。
从实施例1-4、实施例5-1至实施例5-4可以看出，当电解液在包括式(I)所示化合物基础上，还包括环状磺酸酯、式(III)所示化合物或含氰基化合物中的至少两种，可以进一步提高锂离子电池循环性能和降低阻抗。从实施例5-1至实施例5-4可以看出，式(I)所示化合物与环状磺酸酯、式(III)所示化合物、含氰基化合物具有良好的兼容性，组合使用得到的锂离子电池均具有良好的循环性能和安全性能，以及较低的阻抗。
表6
Figure PCTCN2021127986-appb-000030
Figure PCTCN2021127986-appb-000031
注：表6中的实施例中的X＝0.5％，表6中的“/”表示不存在对应制备参数或物质。
电解液中锂盐的质量百分含量、锂盐的种类、隔离膜的热收缩率通常会影响锂离子电池的性能，例如循环性能和安全性能。从实施例1-4、实施例6-1至实施例6-7可以看出，当第一锂盐和第二锂盐的质量百分含量、第一锂盐和第二锂盐的种类、隔离膜的热收缩率在本申请的范围内，得到的锂离子电池具有良好的循环性能和安全性能。
以上所述仅为本申请的较佳实施例，并不用以限制本申请，凡在本申请的精神和原则之内，所做的任何修改、等同替换、改进等，均应包含在本申请保护的范围之内。

Claims (15)

  1. 一种电解液，其包括式(I)所示化合物，基于所述电解液的质量，所述式(I)所示化合物的质量百分含量X为0.05％至3％：
    Figure PCTCN2021127986-appb-100001
    其中，
    R 1和R 2各自独立地选自H、F、C 1至C 5的烷基、C 1至C 5的烷氧基或C 2至C 5的烯基、C 2至C 5的炔基；
    R选自O或-CH(R 3)-，R 3选自H、F、C 1至C 5的烷基、或C 1至C 5的烷氧基；
    Rb选自H、F、C 1至C 5的烷基、或C 1至C 5的烷氧基；
    A和B各自独立地选自-CO-或-SO 2-；
    W选自CH 2或O；
    M -选自基团M1至M3中的一种：
    Figure PCTCN2021127986-appb-100002
  2. 根据权利要求1所述的电解液，其包括下述化合物I-1至I-13中的至少一种：
    Figure PCTCN2021127986-appb-100003
    Figure PCTCN2021127986-appb-100004
  3. 根据权利要求1所述的电解液，其还包括环状磺酸酯，环状磺酸酯包括环状单磺酸酯和/或环状二磺酸酯，基于所述电解液的质量，所述环状磺酸酯的质量百分含量为0.01％至10％；
    所述环状单磺酸酯包括1,3-丙烷磺酸内酯、1,2-丙烷磺酸内酯、1,4-丁烷磺酸内酯、1,2-丁烷磺酸内酯、1,3-丁烷磺酸内酯、2,4-丁烷磺酸内酯或1,3-戊烷磺酸内酯中的至少一种；
    所述环状二磺酸酯包括甲烷二磺酸亚甲酯和/或甲烷二磺酸亚乙酯。
  4. 根据权利要求1所述的电解液，其还包括式(II)所示的化合物：
    Figure PCTCN2021127986-appb-100005
    其中，D和E各自独立地选自C 1至C 8的亚烷基或C 1至C 8的氟代亚烷基，L选自单 键或-OSO 2-。
  5. 根据权利要求1所述的电解液，其包括式(II-1)所示化合物和/或式(II-2)所示化合物：
    Figure PCTCN2021127986-appb-100006
    其中，R 6和R 7各自独立地选自H、F或C 1至C 4的烷基，n3为1、2、3或4；
    Figure PCTCN2021127986-appb-100007
    其中，D和E各自独立地选自C 1至C 8的亚烷基或C 1至C 8的氟代亚烷基。
  6. 根据权利要求1所述的电解液，其还包括式(III)所示化合物，基于所述电解液的质量，所述式(III)所示化合物的质量百分含量C为0.5％至16％，且0.03≤X/C≤1：
    Figure PCTCN2021127986-appb-100008
    其中，R 12至R 15各自独立地选自H、F、C 1至C 10的氟代烷基、C 1至C 10的氟代烷氧基或C 1至C 10的氟代烷氧基烷基，且R 12至R 15不同时为H。
  7. 根据权利要求1所述的电解液，其包括下述化合物III-1至III-6中的至少一种：
    Figure PCTCN2021127986-appb-100009
  8. 根据权利要求1所述的电解液，其还包括含氰基化合物，所述含氰基化合物包括式(IV)至式(VII)所示化合物中的至少一种，基于所述电解液的质量，所述含氰基化合物的质量百分含量D为0.2％至10％：
    Figure PCTCN2021127986-appb-100010
    其中，R 16选自未取代或被Ra取代的C 1至C 12的亚烷基、未取代或被Ra取代的C 1至C 12的亚烷氧基；R 17和R 18各自独立地选自单键、未取代或被Ra取代的C 1至C 12的亚烷基、未取代或被Ra取代的C 1至C 12的亚烷氧基；R 19至R 21各自独立地选自单键、未取代或被Ra取代的C 1至C 12的亚烷基、未取代或被Ra取代的C 1至C 12的亚烷氧基、未取代或被Ra取代的C 1至C 12的亚烷氧基烷基；R 22和R 23各自独立地选自未取代或被Ra取代的C 1至C 12的亚烷基、未取代或被Ra取代的C 2至C 12的亚烯基、未取代或被Ra取代的C 6至C 26的亚芳基、未取代或被Ra取代的C 2至C 12的亚杂环基；R 24至R 27各自独立地选自未取代或被Ra取代的C 1至C 12的亚烷氧基烷基；各个基团的取代基Ra各自独立地选自卤素。
  9. 根据权利要求8所述的电解液，其满足0.05≤X/D≤1。
  10. 根据权利要求1所述的电解液，其包括下述化合物IV-1至IV-4、V-1至V-3、VI-1至VI-4、VII-1至VIII-1中的至少一种：
    Figure PCTCN2021127986-appb-100011
  11. 根据权利要求1所述的电解液，其满足以下条件中的至少一者：
    (i)所述电解液包括第一锂盐，所述第一锂盐包括六氟磷酸锂、双三氟甲烷磺酰亚胺锂、双(氟磺酰)亚胺锂或二氟草酸硼酸锂中的至少一种，基于所述电解液的质量，所述第一锂盐的质量百分含量Y为5％至13％；
    (ii)所述电解液包括第二锂盐，所述第二锂盐包括二氟磷酸锂和/或双草酸硼酸锂，基于所述电解液的质量，所述第二锂盐的质量百分含量Y1为0.05％至1％。
  12. 一种电化学装置，其包括正极和权利要求1至11中任一项所述的电解液，所述电化学装置经过至少400圈循环后，在拆解得到的正极的拉曼光谱图中，满足2≤R2/R1≤4，其中，R1为620cm -1至700cm -1之间最大的峰强度值，R2为500cm -1至600cm -1之间最大的峰强度值。
  13. 根据权利要求12所述的电化学装置，其还包括负极，所述负极包括负极材料层，所述电化学装置经过至少400圈循环后，基于所述负极材料层的质量，拆解得到的负极表 面的Co的质量百分含量小于或等于0.12％。
  14. 根据权利要求12所述的电化学装置，其满足以下条件中的至少一者：
    (iii)在所述正极在升温速度为10℃/分的示差扫描热量测定中，在140℃至163℃的范围内至少出现一个吸热峰；
    (iv)所述电化学装置还包括隔离膜，所述隔离膜在135℃下的热收缩率为2％至5％。
  15. 一种电子装置，其包括权利要求12至14中任一项所述的电化学装置。
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