Electrolytes, electrochemical devices and electronic devices comprising the same

Abstract

The application discloses an electrolyte, an electrochemical device and an electronic device comprising the same, and belongs to the technical field of energy storage. A first additive disclosed by the application integrates three key functional groups, -NCO, -CN and -F, in a benzene ring molecule through a covalent bond. The three functional groups can play a role in an orderly and synergistic manner: -NCO removes H2O / HF first, -CN then reacts with the electrode surface and regulates lithium ion flow, and -F contributes to the generation of a solid interface rich in LiF throughout the process. After the reduction / oxidation decomposition of the first additive at the electrode interface (especially the positive electrode), an organic-inorganic composite solid electrolyte interface film (SEI film) and a positive electrode electrolyte interface film (CEI film) can be formed. The SEI film and the CEI film have both the flexibility of the organic component and the high ion conductivity and mechanical strength of the inorganic component (such as LiF, Li x N y ), can more effectively inhibit the continuous decomposition of the electrolyte, the dissolution of transition metals and the growth of lithium dendrites, effectively improve the cycle performance and high-temperature resistance of the electrochemical device, and reduce the DCR.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, and more specifically, to electrolytes and electrochemical and electronic devices comprising the same. Background Technology

[0002] Electrochemical devices (such as lithium-ion batteries) are widely used in electric vehicles and consumer electronics products due to their advantages such as high energy density, high output power, long cycle life and low environmental pollution.

[0003] With the widespread application of electrochemical devices, higher requirements are being placed on their high-temperature resistance and cycle performance. As a crucial component of electrochemical devices, the electrolyte has a significant impact on their high-temperature resistance and cycle performance.

[0004] Therefore, this application is submitted. Summary of the Invention

[0005] The purpose of this application is to overcome the shortcomings of the prior art and provide an electrolyte and an electrochemical device and electronic device containing the electrolyte, wherein the electrolyte can effectively improve the cycle performance and high temperature resistance of the electrochemical device and reduce the DC internal resistance (DCR).

[0006] To achieve the above objectives, a first aspect of this application provides an electrolyte comprising a first additive, wherein the first additive comprises at least one compound of formula I: R1 includes at least one of formonitrile, acetonitrile, propionitrile, and butyronitrile. R2 includes at least one of F, substituted or unsubstituted C1-C10 fluoroalkyl, H, substituted or unsubstituted C1-C10 hydrocarbon groups; R3 includes at least one of F, substituted or unsubstituted C1-C10 fluoroalkyl, H, substituted or unsubstituted C1-C10 hydrocarbon groups; R4 includes at least one of H, isocyanate group, toluene diisocyanate group, isophorone diisocyanate group, hexamethylene diisocyanate group, and diphenylmethane diisocyanate group; R5 includes at least one of H, isocyanate group, toluene diisocyanate group, isophorone diisocyanate group, hexamethylene diisocyanate group, and diphenylmethane diisocyanate group; R6 includes at least one of H, substituted or unsubstituted C1-C10 hydrocarbon groups; At least one of R2 and R3 includes F or a substituted or unsubstituted C1-C10 fluorinated alkyl group; At least one of R4 and R5 includes an isocyanate group, a toluene diisocyanate group, an isophorone diisocyanate group, a hexamethylene diisocyanate group, or a diphenylmethane diisocyanate group.

[0007] In some of these implementations, at least one of (a) to (f) is satisfied: (a) R1 includes at least one of formonitrile group and acetonitrile group; (b) R2 includes at least one of F, substituted or unsubstituted C1-C5 fluoroalkyl groups, and H; (c) R3 includes at least one of F, substituted or unsubstituted C1-C5 fluoroalkyl groups, and H; (d) R4 includes at least one of H and isocyanate groups; (e) R5 includes at least one of H and isocyanate groups; (f) R6 includes H.

[0008] In some embodiments, the first additive includes at least one of 2-fluoro-4-isocyanate-benzonitrile, 2-trifluoromethyl-4-isocyanate-benzonitrile, 3-trifluoromethyl-5-isocyanate-benzonitrile, 3-fluoro-5-isocyanate-phenylacetonitrile, and 3-trifluoromethyl-4-isocyanate-benzonitrile.

[0009] In some embodiments, the first additive has a mass percentage content of 0.1 to 10% in the electrolyte.

[0010] In some embodiments, the first additive has a mass percentage of 0.3-5% in the electrolyte.

[0011] In some embodiments, the electrolyte further includes a second additive, which includes at least one of vinyl sulfate, fluorovinyl carbonate, lithium disulfonylimide, lithium difluorophosphate, tris(trimethylsilyl) phosphate, tris(trimethylsilyl) phosphite, methanedisulfonate, propylene-1,3-sulfonyl lactone, and transbutenedionitrile.

[0012] In some embodiments, the second additive has a mass percentage content of 0.1 to 10% in the electrolyte.

[0013] In some embodiments, the electrolyte further includes a lithium salt, which includes at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis(oxalato)borate, lithium difluorodioxalatophosphate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, and lithium perchlorate; and / or The electrolyte also includes an organic solvent, which includes cyclic carbonates, chain carbonates, and carboxylic acid esters.

[0014] In some of these implementations, at least one of the following (1) to (7) is satisfied: (1) The lithium salt in the electrolyte has a mass percentage content of 5-20%; (2) The cyclic carbonate includes at least one of ethylene carbonate, propylene carbonate, vinylene carbonate, and vinyl ethylene carbonate; (3) The chain carbonate includes at least one of methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, and dipropyl carbonate; (4) The carboxylic acid ester includes at least one of methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, and propyl propionate; (5) The cyclic carbonate accounts for 10-80% of the mass percentage of the organic solvent; (6) The chain carbonate accounts for 10-50% of the mass percentage of the organic solvent; (7) The carboxylic acid ester accounts for 10 to 40% of the mass percentage of the organic solvent.

[0015] A second aspect of this application provides an electrochemical device comprising the electrolyte described above.

[0016] A third aspect of this application provides an electronic device including the electrochemical device described above.

[0017] The beneficial effects of this application are as follows: The first additive described in this application integrates three key functional groups—-NCO, -CN, and -F—within a single benzene ring molecule via covalent bonds. These three functional groups function in an ordered and synergistic manner: -NCO first removes H2O / HF, -CN then interacts with the electrode surface and regulates the lithium-ion flow, while -F contributes to the formation of a robust LiF-rich interface throughout the process. After reduction / oxidation decomposition at the electrode interface (especially the positive electrode), the first additive can form an organic-inorganic composite solid electrolyte interphase (SEI) film and a positive electrode electrolyte interphase (CEI) film. The formed SEI and CEI films possess both the flexibility of organic components and the properties of inorganic components (such as LiF, Li...). x N y Its high ionic conductivity and mechanical strength can more effectively suppress the continuous decomposition of electrolyte, dissolution of transition metals and growth of lithium dendrites, effectively improve the cycle performance and high temperature resistance of electrochemical devices, and reduce DCR. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0020] In this application, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0021] In this application, there are no particular restrictions on the specific dispersion and mixing methods.

[0022] Unless otherwise specified, all components, raw materials, or instruments used in the embodiments and comparative examples of this application are commercially available, and the components and raw materials used in each parallel experiment are the same.

[0023] In the following description, all figures disclosed herein are approximate values, regardless of whether the terms "about" or "approximately" are used in conjunction. They may vary by 1%, 2%, 5%, or sometimes 10% to 20%. Whenever a range of values ​​with a lower limit RL and an upper limit RU is disclosed, any values ​​falling within that range are specifically disclosed. Specifically, the following values ​​within this range are specifically disclosed: R = RL + k * (RU - RL), where k is a variable with a 1% increment from 1% to 100%, i.e., k is 1%, 2%, 3%, 4%, 5%, ..., 50%, 51%, 52%, ..., 95%, 96%, 97%, 98%, 99%, or 100%. Furthermore, any range of values ​​defined by the two R values ​​as defined above are also specifically disclosed.

[0024] I. Electrolyte This application provides an electrolyte comprising a first additive, wherein the first additive comprises at least one compound of formula I: R1 includes at least one of formonitrile, acetonitrile, propionitrile, and butyronitrile. R2 includes at least one of F, substituted or unsubstituted C1-C10 fluoroalkyl, H, substituted or unsubstituted C1-C10 hydrocarbon groups; R3 includes at least one of F, substituted or unsubstituted C1-C10 fluoroalkyl, H, substituted or unsubstituted C1-C10 hydrocarbon groups; R4 includes at least one of H, isocyanate group, toluene diisocyanate group, isophorone diisocyanate group, hexamethylene diisocyanate group, and diphenylmethane diisocyanate group; R5 includes at least one of H, isocyanate group, toluene diisocyanate group, isophorone diisocyanate group, hexamethylene diisocyanate group, and diphenylmethane diisocyanate group; R6 includes at least one of H, substituted or unsubstituted C1-C10 hydrocarbon groups; At least one of R2 and R3 includes F or a substituted or unsubstituted C1-C10 fluorinated alkyl group; At least one of R4 and R5 includes an isocyanate group, a toluene diisocyanate group, an isophorone diisocyanate group, a hexamethylene diisocyanate group, or a diphenylmethane diisocyanate group.

[0025] The first additive described in this application integrates three key functional groups—-NCO, -CN, and -F—within a single benzene ring molecule via covalent bonds. These three functional groups function in an ordered and synergistic manner: -NCO first removes H₂O / HF, -CN then interacts with the electrode surface and regulates the lithium-ion flow, while -F contributes to the formation of a robust LiF-rich interface throughout the process. After reduction / oxidative decomposition at the electrode interface (especially the positive electrode), the first additive can form an organic-inorganic composite solid electrolyte interphase (SEI) film and a positive electrode electrolyte interphase (CEI) film. The formed SEI and CEI films possess both the flexibility of organic components and the properties of inorganic components (such as LiF, Li₂, Li₃, and Li₂). x N y Its high ionic conductivity and mechanical strength can more effectively suppress the continuous decomposition of electrolyte, dissolution of transition metals and growth of lithium dendrites, effectively improve the cycle performance and high temperature resistance of electrochemical devices, and reduce DCR.

[0026] Understandably, gas chromatography-mass spectrometry (GC-MS) can generally be used to test compounds represented by Formula I, and ion chromatography or inductively coupled plasma mass spectrometry can be used to confirm the types of elements R1 to R6 in the compound. For example, a battery can be disassembled, the electrolyte removed, and the electrolyte diluted and calibrated. GC-MS can then be used to test the organic compounds in the electrolyte. During GC-MS, the gaseous molecules separated by gas chromatography are bombarded by the ion source, electrolyzed and broken down into molecular ions, which are further fragmented into fragment ions. Under the combined action of electric and magnetic fields, they are separated according to their m / z values, detected, recorded, and processed by the detector to obtain a mass spectrum, enabling qualitative and quantitative analysis of the sample.

[0027] Among them, the hydrocarbon group in C1-C10 hydrocarbon group (hydrocarbon group with 1 to 10 carbon atoms) refers to the free radical of saturated or unsaturated aliphatic group, including straight-chain alkyl, straight-chain alkenyl, straight-chain alkynyl, branched-chain alkyl, branched-chain alkenyl, branched-chain alkynyl, cycloalkyl, cycloalkenyl, and cycloalkynyl.

[0028] For example, C1-C10 hydrocarbon groups include C1-C10 saturated alkyl groups, C2-C10 alkenyl groups, and C2-C10 alkynyl groups. Further, straight-chain alkyl groups with 1 to 6 carbon atoms, branched alkyl groups with 2 to 6 carbon atoms, cyclic alkyl groups with 1 to 6 carbon atoms, straight-chain alkenyl groups with 2 to 6 carbon atoms, branched alkenyl groups with 2 to 6 carbon atoms, and cyclic alkenyl groups with 2 to 6 carbon atoms can be selected. Examples of alkyl groups include: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, cyclopentyl, and cyclohexyl. Examples of alkenyl groups include: vinyl, allyl, isopropenyl, pentenyl, cyclohexenyl, cycloheptenyl, and cyclooctenyl. Examples of alkynyl groups include: ethynyl, propynyl, isopropynyl, pentyynyl, and cyclohexynyl.

[0029] The term “substituted or unsubstituted C1-C10 hydrocarbon group” includes substituted C1-C10 hydrocarbon groups and unsubstituted C1-C10 hydrocarbon groups; wherein a substituted C1-C10 hydrocarbon group means that one or more substituents replace hydrogen on one or more carbons in the hydrocarbon chain, and such substituents are selected from at least one of C1-C5 alkyl groups and halogens.

[0030] In C1-C5 alkyl groups (hydrocarbon groups with 1 to 5 carbon atoms), alkyl refers to the free radical of a saturated or unsaturated aliphatic group, including straight-chain alkyl, straight-chain alkenyl, straight-chain alkynyl, branched-chain alkyl, branched-chain alkenyl, branched-chain alkynyl, cycloalkyl, cycloalkenyl, and cycloalkynyl.

[0031] For example, C1-C5 alkyl groups include C1-C5 saturated alkyl groups, C2-C5 alkenyl groups, and C2-C5 alkynyl groups. Examples of alkyl groups include: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, and cyclopentyl; examples of alkenyl groups include: vinyl, allyl, isopropenyl, and pentenyl.

[0032] In some embodiments, the halogen is selected from at least one of F, Cl, and Br.

[0033] When the aforementioned alkyl groups with 1 to 10 carbon atoms contain an F atom, they can be fluorinated alkyl groups, such as C1-C10 fluorinated alkyl groups. Further, fluorinated alkyl groups with 1 to 6 carbon atoms can be selected as examples of fluorinated alkyl groups, specifically including: CH2F, CHF2, CF3, C2F5, CH2CHF2, CH2CH2F, CHFCF3, C3F7, CF2CHF2CHF2, CHFCH2FCH2F, C4F9, C5F... 11 C6F 13 ,CF2CH3.

[0034] The term "substituted or unsubstituted C1-C10 fluoroalkyl group" includes substituted C1-C10 fluoroalkyl groups. 10 Fluoroalkyl and unsubstituted C1-C 10 Fluoroalkyl groups; wherein the substituted C1-C 10 An alkoxy group is a group in which one or more substituents replace hydrogen atoms on one or more carbons in an alkoxy chain. Such substituents are selected from at least one of C1-C5 alkyl, halogen, cyano, carboxyl, sulfonic acid, and sulfonyl groups.

[0035] In some embodiments, R1 includes at least one of formonitrile group and acetonitrile group.

[0036] In some embodiments, R2 includes at least one of F, substituted or unsubstituted C1-C5 fluoroalkyl groups, and H.

[0037] In some embodiments, R3 includes at least one of F, substituted or unsubstituted C1-C5 fluoroalkyl groups, and H.

[0038] In some embodiments, R4 includes at least one of H and isocyanate groups.

[0039] In some embodiments, R5 includes at least one of H and isocyanate groups.

[0040] In some of these implementations, R6 includes H.

[0041] In some embodiments, the first additive includes 2-fluoro-4-isocyanate-benzonitrile (CAS No.: 1261606-20-5), 2-trifluoromethyl-4-isocyanate-benzonitrile (CAS No.: 143782-18-7), 3-trifluoromethyl-5-isocyanate-benzonitrile (CAS No.: 2369052-28-6), 3-fluoro-5-isocyanate-phenylacetonitrile (CAS No.: 1261862-00-3), and 3-trifluoromethyl-4-isocyanate-benzonitrile (CAS No.: 2369052-28-6). At least one of 1354896-26-6), especially when using such a first additive, the first additive simultaneously contains fluorine, nitrile and NCO groups. The nitrile group on the benzene ring has a strong coordination ability and can coordinate with transition metal ions in the cathode material, inhibiting their dissolution and effectively improving the structural stability of the cathode active material. At the same time, it participates in the construction of the CEI film and guides the uniform deposition of lithium ions. The NCO group on the benzene ring can react with H2O and HF in the electrolyte during the formation process, which can remove water and acidic substances in the electrolyte, generate urea and amide substances, reduce the occurrence of side reactions, and the generated urea and amide substances participate in the formation of a stable interface film. The fluorine atom on the benzene ring can effectively reduce the molecular energy level and improve the antioxidant performance of the electrolyte (i.e., stability at higher voltages). At the same time, after reduction / oxidation decomposition, it is easy to generate LiF with high ionic conductivity, which improves ionic conductivity and interface stability, promotes the formation of a more stable and dense SEI film and CEI film, further improves the cycle performance and high temperature resistance of the electrochemical device, and further reduces DCR.

[0042] In some embodiments, the first additive has a mass percentage content of 0.1 to 10% in the electrolyte, for example, it can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 6%, 7%, 8%, 9%, 10%, or any two of these values.

[0043] In some embodiments, the first additive has a mass percentage content of 0.3-5% in the electrolyte. In particular, controlling the mass percentage content of the first additive in the electrolyte within this range can further improve the cycle performance and high temperature resistance of the electrochemical device, and further reduce DCR.

[0044] In some embodiments, the electrolyte further includes a second additive, which includes at least one of vinyl sulfate, fluorovinyl carbonate, lithium disulfonylimide, lithium difluorophosphate, tris(trimethylsilyl) phosphate, tris(trimethylsilyl) phosphite, methanedisulfonate, propylene-1,3-sulfonyl lactone, and transbutenedionitrile.

[0045] In some embodiments, the second additive has a mass percentage content of 0.1 to 10% in the electrolyte, for example, it can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 6%, 7%, 8%, 9%, 10%, or any two of these values.

[0046] In some embodiments, the second additive has a mass percentage of 2-4% in the electrolyte. In particular, controlling the content of the second additive within this range enables it to form a more stable and dense SEI and CEI film with the first additive, effectively suppressing interfacial side reactions, further improving the cycle performance and high-temperature resistance of the electrochemical device, and further reducing DCR.

[0047] In some embodiments, the second additive comprises fluoroethylene carbonate and ethylene sulfate in a mass ratio of 1:(1~3).

[0048] In some embodiments, the electrolyte further includes a lithium salt, which includes at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis(oxalato)borate, lithium difluorodioxalatophosphate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, and lithium perchlorate.

[0049] In some embodiments, the electrolyte further includes an organic solvent, including cyclic carbonates, chain carbonates, and carboxylic acid esters. In particular, such organic solvents have good compatibility with the first additive and can optimize the ionic conductivity, wettability, thermal stability, and volatility of the electrolyte, thereby improving the overall performance of the electrochemical device.

[0050] In some embodiments, the lithium salt has a mass percentage content of 5-20% in the electrolyte, for example, it can be 5%, 6%, 8%, 10%, 12%, 14%, 15%, 16%, 18%, 20% or any two of these values. By controlling the concentration of the lithium salt within this range, the conductivity of the electrolyte can be improved, the conduction of lithium ions can be promoted, and the stability of the electrolyte can be improved.

[0051] In some embodiments, the cyclic carbonate includes at least one of ethylene carbonate, propylene carbonate, vinylene carbonate, and vinyl ethylene carbonate.

[0052] In some embodiments, the chain carbonate includes at least one of methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, and dipropyl carbonate.

[0053] In some embodiments, the carboxylic acid ester includes at least one selected from methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, and propyl propionate.

[0054] In some embodiments, the cyclic carbonate accounts for 10-80% of the organic solvent by mass, for example, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, or any two of these values.

[0055] In some embodiments, the chain carbonate accounts for 10-50% of the organic solvent by mass, for example, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, or any two of these values.

[0056] In some embodiments, the carboxylic acid ester accounts for 10-40% of the organic solvent by mass, for example, it can be 10%, 15%, 20%, 25%, 30%, 35%, 40%, or any two of these values.

[0057] In some embodiments, the cyclic carbonate accounts for 42-60% of the organic solvent by mass.

[0058] In some embodiments, the chain carbonate accounts for 20-30% of the mass percentage of the organic solvent.

[0059] In some embodiments, the carboxylic acid ester accounts for 20-28% of the mass percentage of the organic solvent.

[0060] By controlling the mass percentage of cyclic carbonates, chain carbonates, and carboxylic esters in the organic solvent within the above-mentioned range, the wetting performance of the electrodes (positive and negative electrodes) can be effectively improved, providing better electron conduction and ion diffusion channels, reducing internal resistance, and improving cycle performance.

[0061] II. Electrochemical Device This application provides an electrochemical device comprising the electrolyte described above. In some embodiments, the electrochemical device further includes a positive electrode, a negative electrode, and a separator, wherein the separator is located between the positive and negative electrode.

[0062] The electrochemical device of this application includes any device in which an electrochemical reaction occurs, and specific examples include all kinds of primary batteries, secondary batteries, fuel cells, solar cells, or capacitors. In particular, the electrochemical device is a lithium secondary battery, including lithium metal secondary batteries, lithium-ion secondary batteries, lithium polymer secondary batteries, or lithium-ion polymer secondary batteries.

[0063] Negative electrode sheet The negative electrode sheet includes a negative current collector and a negative active layer disposed on at least one side of the negative current collector, wherein the negative active layer includes a negative active material, a negative binder, and a negative conductive agent.

[0064] In this application, there are no particular restrictions on the negative electrode current collector, as long as it can achieve the purpose of this application. For example, it can be copper foil, copper alloy foil, nickel foil, stainless steel foil, titanium foil, foamed nickel, foamed copper, or composite current collector, etc.

[0065] In some embodiments, the negative electrode active material includes natural graphite particles, synthetic graphite particles, hard carbon, soft carbon, mesophase carbon microspheres (MCMB), Sn, SnO2, SnO, and Li4Ti5O. 12 The material is selected from at least one of the following: LTO, Si material, silicon-carbon (Si-C) composite material, silicon-nitrogen (Si-N) composite material, and silicon-oxygen (Si-O) composite material. This application is not limited to the above-mentioned materials, but also includes other materials that can be used as negative electrode active materials in batteries.

[0066] In some embodiments, the negative electrode active material includes pre-lithiated graphite, wherein the degree of pre-lithiation of the graphite is 0.04 to 0.2, for example, it can be 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20 or any two of these values. By controlling the degree of pre-lithiation of the graphite within this range, active lithium can be compensated for, thereby improving the battery's initial efficiency and covering the active lithium loss caused by the sulfur cathode shuttle effect during charge and discharge processes, and improving the specific capacity of the mixed cathode.

[0067] In some embodiments, the negative electrode binder includes at least one of the following: polyacrylic acid, polymethacrylic acid, polyacrylate, polymethacrylate, polyacrylamide, styrene-butadiene rubber, acrylic styrene-butadiene rubber, acrylic acid-acrylonitrile-acrylamide copolymer, acrylic acid-acrylonitrile-acrylate copolymer, acrylonitrile-butadiene rubber, nitrile rubber, acrylonitrile-styrene-butadiene copolymer, acryloyl rubber, butyl rubber, fluororubber, polytetrafluoroethylene, polyvinyl alcohol, polyvinyl acetate, polyepoxychloropropane, polyphosphazene, polyacrylonitrile, polystyrene, latex, acrylic resin, phenolic resin, epoxy resin, carboxymethyl cellulose, hydroxypropyl cellulose, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl cellulose, carboxymethyl chitosan, polyester, polyamide, polyether, polyimide, polycarboxylic acid ester, polycarboxylic acid, polyurethane, alginate, fluorinated polymer, chlorinated polymer, polyvinylidene fluoride, and poly(vinylidene fluoride)-hexafluoropropylene. This application is not limited to the above materials and also includes other materials that can be used as battery negative electrode binders.

[0068] In some embodiments, the negative electrode conductive agent includes at least one of carbon, graphite, expanded graphite, graphene, graphene nanosheets, superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon fibers, carbon nanofibers, graphitized carbon sheets, carbon tubes, carbon nanotubes, activated carbon, and mesoporous carbon. This application is not limited to the above materials, but also includes other materials that can be used as negative electrode conductive agents in batteries.

[0069] Positive electrode sheet The electrochemical device of this application includes a positive electrode, wherein the positive electrode includes a positive current collector and a positive active layer disposed on at least one surface of the positive current collector.

[0070] In some of these embodiments, the type of positive current collector is not particularly limited, and it may be any material known to be suitable for use as a positive current collector.

[0071] In some embodiments, the positive current collector includes metallic materials such as aluminum, stainless steel, nickel plating, titanium, and tantalum, as well as carbon materials such as carbon cloth and carbon paper.

[0072] There are no particular restrictions on the form of the positive electrode current collector. When the positive electrode current collector is a metallic material, it can be in the form of metal foil, metal cylinder, metal strip, metal plate, metal foil, metal mesh, stamped metal, foamed metal, etc. When the positive electrode current collector is a carbon material, it can be in the form of carbon plate, carbon film, carbon cylinder, etc.

[0073] In some embodiments, the positive electrode active layer includes a positive electrode active material, a positive electrode binder, and a positive electrode conductive agent.

[0074] In some embodiments, the positive electrode active material is selected from LiCoO2, LiNiO2, and LiNi. x Mn y O2, Li 1+ z Ni x Mn y Co 1-x-y O2, LiNi x Co y Al z The group consisting of O2, LiV2O5, LiTiS2, LiMoS2, LiMnO2, LiCrO2, LiMn2O4, Li2MnO3, LiFeO2, LiFePO4, LiMnPO4 and combinations thereof, wherein each x is independently 0.2 to 0.9; each y is independently 0.1 to 0.45; and each z is independently 0 to 0.2.

[0075] In some embodiments, the positive electrode active material is Li 1+x Ni a Mn b Co c Al (1-a-b-c) O2; where -0.2≤x≤0.2, 0≤a<1, 0≤b<1, 0≤c<1 and a+b+c≤1.

[0076] In some embodiments, the positive electrode active material has the general formula Li 1+x Ni a Mn b Co c Al (1-a-b-c) O2, where 0.33≤a≤0.92, 0.33≤a≤0.9, 0.33≤a≤0.8, 0.5≤a≤0.92, 0.5≤a≤0.9, 0.5≤a≤0.8, 0.6≤a≤0.92 or 0.6≤a≤0.9; 0≤b≤0.5, 0≤b≤0.3, 0.1≤b≤0.5, 0.1≤b≤0.4, 0.1≤b≤0.3, 0.1≤b≤0.2 or 0.2≤b≤0.5; 0≤c≤0.5, 0≤c≤0.3, 0.1≤c≤0.5, 0.1≤c≤0.4, 0.1≤c≤0.3, 0.1≤c≤0.2 or 0.2≤c≤0.5.

[0077] In some embodiments, the positive electrode active material is doped with a dopant selected from the group consisting of Fe, Ni, Mn, Al, Mg, Zn, Ti, La, Ce, Sn, Zr, Ru, Si, Ge, and combinations thereof.

[0078] In some embodiments, the positive electrode active material includes LiNi. 0.33Mn 0.33 Co 0.33 O2(NMC333), LiNi 0.4 Mn 0.4 Co 0.2 O2, LiNi 0.5 Mn 0.3 Co 0.2 O2(NMC532), LiNi 0.6 Mn 0.2 Co 0.2 O2(NMC622), LiNi 0.7 Mn 0.15 Co 0.15 O2, LiNi 0.8 Mn 0.1 Co 0.1 O2(NMC811), LiNi 0.92 Mn 0.04 Co 0.04 O2, LiNi 0.8 Co 0.15 Al 0.05 At least one of O2 (NCA) and LiNiO2 (LNO).

[0079] In some embodiments, the positive electrode binder includes binder materials comprising at least one of the following: polyvinylidene fluoride (PVDF), poly(vinylidene fluoride)-hexafluoropropylene (PVDF-HFP), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, fluorinated acrylate resin, polyacrylic acid, polyacrylonitrile, polyimide, polyurethane, polyvinyl butyral, polyvinylpyrrolidone (PVP), acrylic acid-acrylonitrile-acrylamide copolymer, and acrylic acid-acrylonitrile-acrylate copolymer. This application is not limited to the above materials and also includes other materials that can be used as battery positive electrode binders.

[0080] In some embodiments, the positive electrode conductive agent includes at least one of carbon, graphite, expanded graphite, graphene, graphene nanosheets, superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon fibers, carbon nanofibers, graphitized carbon sheets, carbon tubes, carbon nanotubes, activated carbon, and mesoporous carbon. This application is not limited to the above materials, but also includes other materials that can be used as positive electrode conductive agents in batteries.

[0081] diaphragm The separator separates the negative and positive electrodes and provides a pathway for lithium-ion migration. The use of the separator is not particularly limited, as long as it is a separator commonly used in lithium-ion secondary batteries. In particular, separators with low resistance to electrolyte ion movement and excellent electrolyte permeability are preferred. Specifically, porous polymer membranes can be used, such as porous polymer membranes formed from polyolefin-based polymers (e.g., ethylene homopolymers, propylene homopolymers, ethylene / butene copolymers, ethylene / hexene copolymers, ethylene / methacrylate copolymers, etc.) or laminated structures with two or more layers. Alternatively, nonwoven fabrics formed from conventional porous nonwoven fabrics (e.g., glass fibers with high melting points, polyethylene terephthalate fibers, etc.) can be used. Furthermore, coated separators containing ceramic components or polymer materials to ensure heat resistance or mechanical strength can be used, and can optionally be used as single-layer or multi-layer structures.

[0082] Generally, a diaphragm includes a substrate and a coating applied to the surface of the substrate.

[0083] substrate In some embodiments, the porous substrate is, but is not limited to, at least one of polyolefins, polyesters, polyacetals, polyamides, polyethylene terephthalate, polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenylene ether, polyphenylene sulfide, polyacrylonitrile, polyvinylidene fluoride, polyoxymethylene, polyoxymethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, polytetrafluoroethylene, polysulfone, and polymethyl methacrylate. Some non-limiting examples of polyolefins include at least one of polyethylene (PE), ultra-high molecular weight polyethylene (UHMWPE), high-density polyethylene (HDPE), polypropylene (PP), polyethylene-polypropylene copolymer (PE-PP), and polyethylene-polypropylene-polyethylene copolymer.

[0084] Inorganic particles In some embodiments, the coating is disposed on one side of the substrate. In some embodiments, the coating is disposed on both sides of the substrate. The inorganic filler comprises Al2O3, SiO2, TiO2, ZrO2, Mg(OH)2, MgO, SnO2, CaCO3, BaSO4, TiN, AlN, Na2O.mTiO2, K2O.nTiO2, BaOx, MTiO3, and combinations thereof, wherein m is 3 or 6, n is 1, 2, 4, 6, or 8, x is 1 or 2, and M is Ba, Sr, or Ca.

[0085] In some embodiments, the inorganic filler includes one or more of alumina, hydrated alumina, boehmite, magnesium hydroxide, magnesium oxide, titanium dioxide, zirconium oxide, and barium sulfate.

[0086] Coating adhesive In some embodiments, the binder is a water-soluble polymer. In some embodiments, the water-soluble polymer is a homopolymer or copolymer.

[0087] In some embodiments, the water-soluble binder includes at least one of polyamide, polycarboxylate, polycarboxylic acid, polyacrylic acid, polyacrylate, polymethacrylic acid, polymethacrylate, polyvinyl alcohol, polyvinyl acetate, polyacrylamide, cellulose, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, carboxymethyl cellulose, cyanoethyl cellulose, nitrile rubber (NBR), styrene-butadiene rubber (SBR), and latex.

[0088] In some embodiments, the monomers constituting the water-soluble polymer include at least one of a monomer containing a carboxylic acid group, a monomer containing an amide group, a monomer containing a cyanide group, and a monomer containing an ester group.

[0089] In some embodiments, the monomers containing a carboxylic acid group include monocarboxylic acids, dicarboxylic acids, anhydrides of dicarboxylic acids, and derivatives thereof. Some non-limiting examples of monocarboxylic acids include acrylic acid, methacrylic acid, crotonic acid, 2-ethylacrylic acid, and isocrotonic acid. Some non-limiting examples of dicarboxylic acids include maleic acid, fumaric acid, itaconic acid, and methylmaleic acid. Some non-limiting examples of anhydrides of dicarboxylic acids include maleic anhydride, acrylic anhydride, methylmaleic anhydride, and dimethylmaleic anhydride.

[0090] In some embodiments, the monomer containing an amide group includes at least one of acrylamide and methacrylamide. In some embodiments, the monomer containing a cyano group includes at least one of acrylonitrile and α-alkylacrylonitrile. In some embodiments, the monomer containing a nitrile group is at least one of methacrylonitrile, α-ethylacrylonitrile, α-isopropylacrylonitrile, α-methoxyacrylonitrile, 3-methoxyacrylonitrile, and 3-ethoxyacrylonitrile.

[0091] In some embodiments, the monomer containing an ester group includes at least one of methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate, n-propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n-butyl acrylate, and n-butyl methacrylate.

[0092] In some embodiments, the monomer accounts for 10-90% of the polymer. In some embodiments, the binder is an oil-soluble polymer.

[0093] In some of these embodiments, non-limiting examples of oil-soluble polymers include polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), polyester, polyether, polyvinyl compounds, polyolefins, rubber, polyvinylpyrrolidone, polystyrene, nitrile rubber (NBR), styrene-butadiene rubber (SBR), latex, acrylonitrile-styrene-butadiene copolymer, halogenated polymers, fluorinated polymers, chlorinated polymers, unsaturated polymers, conjugated diene polymers, and combinations thereof.

[0094] polymer coating In some embodiments, the polymer includes at least one of fluoropolymers, polyester polymers, acrylic polymers, polyurethane polymers, polyamide polymers, vinyl polymers, polyether polymers, polycarboxylic acid polymers, cellulose and its derivatives, or rubber / elastomers.

[0095] In some embodiments, the polymer includes at least one of polyvinylidene fluoride (PVDF), a homopolymer or copolymer formed from vinylidene fluoride and another copolymerizable monomer (such as one or more of tetrafluoroethylene, hexafluoropropylene, trifluoroethylene, trichloroethylene, and fluoroethylene), polytetrafluoroethylene, fluorinated ethylene propylene copolymer, perfluorosulfonic acid resin, polycarboxylate, polycaprolactone, polyacrylate, polyurethane, polyamide, polyimide, polyacrylonitrile, polyethylene oxide, polyacrylic acid, polymethacrylic acid, polymethacrylate, polyvinyl alcohol, polyvinyl acetate, polyacrylamide, polyphenylene ether, polyvinyl chloride compound, polystyrene, polyvinylpyrrolidone, acrylonitrile-styrene-butadiene copolymer, polyphenylene sulfide, polyetheretherketone, polyarylamide, polypyrrole, polyaniline, polythiophene, polyethylene glycol, polylactic acid, cellulose (which may be cellulose nanofibers), cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, carboxymethyl cellulose, cyanoethyl cellulose, nitrile rubber (NBR), styrene-butadiene rubber (SBR), and latex.

[0096] In some embodiments, the polyvinylidene fluoride resin includes at least one homopolymer of polyvinylidene fluoride (i.e., polyvinylidene fluoride) and a copolymer formed of polyvinylidene fluoride and another copolymerizable monomer (such as at least one of tetrafluoroethylene, hexafluoropropylene, trifluoroethylene, trichloroethylene, and vinyl fluoride).

[0097] III. Electronic Devices This application also provides an electronic device, including the electrochemical device described in this application.

[0098] The application of the electrochemical device in this application is not particularly limited, and it can be used in any electronic device known in the prior art. In some embodiments, the electrochemical device includes, but is not limited to, mobile phones, smartphones, laptops, tablets, wearable devices, smartwatches, smart bracelets, smart glasses, power banks, televisions, game consoles, game controllers, digital cameras, smart speakers, headphones, keyboards, mice, monitors, drones, audio equipment, home appliances, toys, power tools, automobiles, motorcycles, electric bicycles, bicycles, robots, robot dogs, industrial robots, android robots, etc.

[0099] The following uses a lithium-ion battery as an example and combines specific embodiments to illustrate the preparation of a lithium-ion battery. Those skilled in the art will understand that the preparation method described in this application is only an example, and any other suitable preparation method is within the scope of this application.

[0100] Example 1 A method for preparing a lithium-ion battery includes the following steps: (1) Preparation of positive electrode sheet: The positive electrode active material LiCoO2, conductive agent acetylene black, conductive carbon nanotubes and binder polyvinylidene fluoride (PVDF) are fully dispersed in N-methylpyrrolidone solvent system at a weight ratio of 98.2:0.5:0.3:1.0. The uniformly dispersed slurry is coated on both sides of aluminum foil with a thickness of 9μm, and then dried, cold pressed and slit to obtain positive electrode sheet; (2) Preparation of negative electrode sheet: The negative electrode active material artificial graphite, conductive agent acetylene black (Super P), binder SBR, and thickener sodium carboxymethyl cellulose (CMC) are mixed evenly in the mass ratio of graphite:Super P:SBR:CMC = 96:1:1.5:1.5 and evenly dispersed in deionized water to form a uniform black slurry. The mixed slurry is coated on both sides of a copper foil with a thickness of 7μm, and then dried, cold-pressed, and slit to obtain the negative electrode sheet.

[0101] (3) A PE membrane with a thickness of 7 μm was used as the separator; (4) Preparation of electrolyte: At room temperature, in a glove box filled with argon (H2O<1ppm, O2<1ppm), ethylene carbonate (EC): diethyl carbonate (DEC): propylene carbonate (PC): propyl propionate (PP): vinylene carbonate (VC) are mixed evenly in a mass ratio of 20:30:20:28:2. Lithium salt LiPF6 is added to the mixed organic solvent and stirred evenly. Then 2-fluoro-4-isocyanate benzonitrile (hereinafter referred to as additive A1), vinylene sulfate (PS), and fluoroethylene carbonate (FEC) are added and stirred evenly to obtain the electrolyte.

[0102] The electrolyte contains 8% lithium salt (LiPF6) by mass, and 1%, 1.5%, and 0.5% 2-fluoro-4-isocyanate benzonitrile (additive A1), vinylene sulfate (PS), and fluoroethylene carbonate (FEC) by mass, respectively. (5) Assembly of lithium-ion batteries: The positive electrode, separator and negative electrode are stacked in sequence, so that the separator is between the positive and negative electrode to play a role in isolation. After being wound into a square bare cell, it is put into the outer packaging, then baked to remove water, injected with the corresponding electrolyte, sealed, and after standing, hot and cold pressing, formation and capacity testing, the lithium-ion battery is obtained.

[0103] The parameters of the electrolyte are shown in Table 1.

[0104] Examples 2-6 The difference between Examples 2-6 and Example 1 is that the mass percentage of additive A1 in the electrolyte is changed.

[0105] Examples 7-10 The difference between Examples 7-10 and Example 1 is that the type of the first additive is changed.

[0106] In Example 7, 3-trifluoromethyl-5-isocyanate-based benzonitrile (hereinafter referred to as additive A2) was used.

[0107] Example 8 uses 3-trifluoromethyl-4-isocyanate-based benzonitrile (hereinafter referred to as additive A3).

[0108] Example 9 uses 3-fluoro-5-isocyanate-based phenylacetonitrile (hereinafter referred to as additive A4).

[0109] Example 10 uses 2-trifluoromethyl-4-isocyanate benzonitrile (hereinafter referred to as additive A5).

[0110] Examples 11-16 The difference between Examples 11-16 and Example 1 is that Examples 11-15 change the mass percentage content of the second additive in the electrolyte, as shown in Table 1.

[0111] Example 17 Example 17 differs from Example 1 in that the type of the second additive is changed.

[0112] Example 17 uses an equal amount of propylene-1,3-sulfonyl lactone (PST) to replace vinylene sulfate (PS) and an equal amount of lithium difluorophosphate (LiPO2F2) to replace fluoroethylene carbonate (FEC).

[0113] Examples 18-20 The difference between Examples 18-20 and Example 1 is that the ratio of the organic solvent is changed, as shown in Table 1.

[0114] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that Comparative Example 1 did not include additive A1.

[0115] Comparative Examples 2-8 The difference between Comparative Examples 2-8 and Example 1 is that Comparative Examples 2-8 use other additives to replace additive A1, as shown in Table 1.

[0116] Table 1 Performance testing (1) Room temperature cycling performance test Five lithium-ion secondary batteries from the comparative example and the embodiment were taken and charged at 25°C with a constant current at a 1C rate until the voltage reached 4.55V. They were then further charged at a constant voltage of 4.3V until the current dropped below 0.05C, bringing them to a fully charged state of 4.55V. Subsequently, they were discharged at a constant current at a 1C rate until the voltage reached 3.0V. The capacity retention rate was calculated after 500 cycles.

[0117] The capacity retention rate during room temperature cycling is calculated as follows: (Discharge capacity of the 500th cycle / Discharge capacity of the first cycle) × 100%.

[0118] (2) Cyclic performance test at 45℃ Five lithium-ion secondary batteries from the comparative example and the embodiments were taken and charged at 45°C with a constant current at a 1C rate until the voltage reached 4.55V. They were then further charged at a constant voltage of 4.3V until the current dropped below 0.05C, bringing them to a fully charged state of 4.55V. Subsequently, they were discharged at a constant current at a 1C rate until the voltage reached 3.0V. The capacity retention was calculated after 500 cycles.

[0119] 45℃ cycle capacity retention rate = (discharge capacity of the 500th cycle / discharge capacity of the first cycle) × 100%.

[0120] (3) Storage performance test at 60°C: The fully charged (4.55V) battery was stored at 60°C for 7 days and the thickness expansion rate was measured after it was restored to room temperature.

[0121] Thickness expansion rate = ((battery thickness after storage - initial thickness) / initial thickness) × 100%.

[0122] (4) DC internal resistance (DCR) growth: Measure the DC internal resistance of the battery before and after cycling at the same SOC, and calculate the DCR growth rate.

[0123] DCR growth rate = (DCR after the 500th cycle - DCR before the last cycle / DCR before the last cycle) × 100%.

[0124] Table 2 As can be seen from Table 2, the first additive described in this application can effectively improve the cycle performance and high temperature resistance of the electrochemical device, and reduce DCR.

[0125] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit the scope of protection of this application. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the substance and scope of the technical solutions of this application.

Claims

1. An electrolyte, characterized in that, Includes a first additive, which comprises at least one of the compounds shown in Formula I: R1 includes at least one of formonitrile, acetonitrile, propionitrile, and butyronitrile. R2 includes at least one of F, substituted or unsubstituted C1-C10 fluoroalkyl, H, substituted or unsubstituted C1-C10 hydrocarbon groups; R3 includes at least one of F, substituted or unsubstituted C1-C10 fluoroalkyl, H, substituted or unsubstituted C1-C10 hydrocarbon groups; R4 includes at least one of H, isocyanate group, toluene diisocyanate group, isophorone diisocyanate group, hexamethylene diisocyanate group, and diphenylmethane diisocyanate group; R5 includes at least one of H, isocyanate group, toluene diisocyanate group, isophorone diisocyanate group, hexamethylene diisocyanate group, and diphenylmethane diisocyanate group; R6 includes at least one of H, substituted or unsubstituted C1-C10 hydrocarbon groups; At least one of R2 and R3 includes F or a substituted or unsubstituted C1-C10 fluorinated alkyl group; At least one of R4 and R5 includes an isocyanate group, a toluene diisocyanate group, an isophorone diisocyanate group, a hexamethylene diisocyanate group, or a diphenylmethane diisocyanate group.

2. The electrolyte according to claim 1, characterized in that, Satisfy at least one of the following (a) to (f): (a) R1 includes at least one of formonitrile group and acetonitrile group; (b) R2 includes at least one of F, substituted or unsubstituted C1-C5 fluoroalkyl groups, and H; (c) R3 includes at least one of F, substituted or unsubstituted C1-C5 fluoroalkyl groups, and H; (d) R4 includes at least one of H and isocyanate groups; (e) R5 includes at least one of H and isocyanate groups; (f) R6 includes H.

3. The electrolyte according to claim 1, characterized in that, The first additive includes at least one of 2-fluoro-4-isocyanate-benzonitrile, 2-trifluoromethyl-4-isocyanate-benzonitrile, 3-trifluoromethyl-5-isocyanate-benzonitrile, 3-fluoro-5-isocyanate-phenylacetonitrile, and 3-trifluoromethyl-4-isocyanate-benzonitrile.

4. The electrolyte according to claim 1, characterized in that, The first additive has a mass percentage content of 0.1-10% in the electrolyte.

5. The electrolyte according to claim 1, characterized in that, The first additive has a mass percentage content of 0.3-5% in the electrolyte.

6. The electrolyte according to claim 1, characterized in that, The electrolyte further includes a second additive, which includes at least one of vinyl sulfate, fluorovinyl carbonate, lithium disulfonylimide, lithium difluorophosphate, tris(trimethylsilyl) phosphate, tris(trimethylsilyl) phosphite, methanedisulfonate, propylene-1,3-sulfonyl lactone, and transbutenedionitrile.

7. The electrolyte according to claim 6, characterized in that, The second additive has a mass percentage content of 0.1-10% in the electrolyte.

8. The electrolyte according to claim 1, characterized in that, The electrolyte further includes a lithium salt, which includes at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis(oxalato)borate, lithium difluorodi(oxalato)phosphate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, and lithium perchlorate; and / or The electrolyte also includes an organic solvent, which includes cyclic carbonates, chain carbonates, and carboxylic acid esters.

9. The electrolyte according to claim 8, characterized in that, Satisfy at least one of the following (1) to (7): (1) The lithium salt in the electrolyte has a mass percentage content of 5-20%; (2) The cyclic carbonate includes at least one of ethylene carbonate, propylene carbonate, vinylene carbonate, and vinyl ethylene carbonate; (3) The chain carbonate includes at least one of methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, and dipropyl carbonate; (4) The carboxylic acid ester includes at least one of methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, and propyl propionate; (5) The cyclic carbonate accounts for 10-80% of the mass percentage of the organic solvent; (6) The chain carbonate accounts for 10-50% of the mass percentage of the organic solvent; (7) The carboxylic acid ester accounts for 10 to 40% of the mass percentage of the organic solvent.

10. An electrochemical device, characterized in that, Includes the electrolyte as described in any one of claims 1 to 9.

11. An electronic device, characterized in that, Includes the electrochemical device as described in claim 10.

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