Application of compound as electrolyte additive, electrolyte, battery and electric device

Abstract

The invention provides an application of a compound as an electrolyte additive, an electrolyte, a battery and an electric device. The invention relates to application of a compound as shown in a formula I as an electrolyte additive. The compound provided by the invention can capture by-products generated by electrolyte oxygenolysis products, so that the interface impedance of a negative pole piece is prevented from being increased, and the capacity and cycle performance of the battery are further improved.

Description

Application of compound as electrolyte additive, electrolyte, battery and electrical device Technical Field

[0001] The present application relates to the field of battery technology, and in particular to the application of a compound as an electrolyte additive, an electrolyte, a battery, and an electrical device. Background Art

[0002] In recent years, the application of secondary batteries has become increasingly widespread. They are widely used in energy storage systems such as hydropower, thermal, wind, and solar power plants, as well as in power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace, and other fields. The positive electrode of secondary batteries often uses lithium supplements, but there is an urgent need to further improve the battery's capacity and cycle performance while using these supplements.

[0003] Summary of the Invention

[0004] The present application is made in view of the above-mentioned problems, and its purpose is to provide the application of a compound as an electrolyte additive, an electrolyte, a battery and an electrical device. The positive electrode lithium supplement generates oxygen free radicals during the first cycle of charging, and the oxygen free radicals may further generate oxygen. The oxygen free radicals and the oxygen that may be generated easily cause the electrolyte to undergo oxidative decomposition, and the oxidative decomposition products further generate R+ substances. The electrolyte additive of the present application can capture R+ substances, inhibit the reduction reaction of R+ substances in the negative electrode sheet, thereby inhibiting the thickening of the SEI film caused by the reduction of R+ substances, and then inhibiting the increase in the interfacial impedance of the negative electrode sheet caused by the thickening of the SEI film, thereby improving the cycle performance of the battery, and improving the capacity and safety performance of the battery.

[0005] In order to achieve the above-mentioned purpose, the first aspect of the present application provides the use of the compound shown in Formula I as an electrolyte additive.

[0006] in,

[0007] X is selected from O═P, Si and B;

[0008] n is selected from 3 and 4;

[0009] The n R groups are independently selected from hydroxyl, C1-C6 alkoxy, C2-C6 alkynyl, C2-C10 alkenyloxy, and C2-C10 alkynyloxy groups, and at least one of the n R groups includes an unsaturated bond.

[0010] The positive electrode lithium supplement undergoes an irreversible phase change during the first cycle of charging, generating oxygen free radicals, which may further generate oxygen. The oxygen free radicals and the oxygen that may be generated easily lead to oxidative decomposition of the electrolyte, and the oxidative decomposition products further generate R+ substances. The R+ substances are prone to undergo a reduction reaction in the negative electrode, causing the SEI film to thicken, resulting in increased interface impedance, deterioration of battery cycle performance, and even lithium plating, which also affects the battery capacity. The R+ substances may include H generated by the decomposition of the electrolyte salt caused by the decomposition of the solvent in the electrolyte. + and other by-products.

[0011] The electrolyte additive of the present application can capture the R+ substance further generated by the electrolyte oxidation decomposition products, inhibit the reduction of the R+ substance in the negative electrode, thereby inhibiting the thickening of the SEI film caused by the reduction of the R+ substance, and further inhibiting the increase in interfacial impedance caused by the thickening of the SEI film, thereby improving the cycle performance of the battery and improving the capacity and safety performance of the battery.

[0012] In any embodiment, in Formula I, n R are independently selected from hydroxyl, C1-C6 alkoxy, C2-C6 alkynyl, Furthermore, at least one of the n R groups includes an unsaturated bond;

[0013] a, b, c and d are independently selected from 0, 1, 2, 3 and 4.

[0014] As a result, the thickening of the SEI film caused by the reduction of R+ substances in the negative electrode sheet is further inhibited, the interfacial impedance of the negative electrode sheet is further reduced, and the capacity and cycle performance of the battery are improved.

[0015] In any embodiment, in Formula I, n R groups are independently selected from hydroxy, methoxy, ethoxy, ethynyl, propargyl, vinyloxy, allyloxy, propenyloxy, ethynyloxy, propynyloxy, and propargyloxy, and at least one of the n R groups includes an unsaturated bond.

[0016] In any embodiment, the compound is a compound of formula II,

[0017] in,

[0018] R1 is selected from hydroxy, C1-C6 alkoxy, C2-C6 alkynyl, C2-C10 alkenyloxy and C2-C10 alkynyloxy;

[0019] R2 and R3 are independently selected from H, C1-C6 alkyl, C2-C10 alkenyl and C2-C10 alkynyl;

[0020] Furthermore, at least one group among R1, R2 and R3 includes an unsaturated bond.

[0021] The electrolyte additive shown in Formula II can capture the R+ species further generated by the electrolyte oxidation decomposition products, inhibit the thickening of the SEI film caused by the reduction of R+ at the negative electrode, reduce the interface impedance of the negative electrode, and improve the capacity, cycle performance and safety performance of the battery.

[0022] In any embodiment, in formula II, R1 is selected from hydroxyl, C1-C6 alkoxy, C2-C6 alkynyl, R2 and R3 are independently selected from H, C1-C6 alkyl, a, b, c, d, e, f, g, and h are independently selected from 0, 1, 2, 3, and 4; and at least one of R1, R2, and R3 includes an unsaturated bond;

[0023] Optionally, in Formula II, R1 is selected from hydroxy, methoxy, ethoxy, ethynyl, propargyl, vinyloxy, allyloxy, propenyloxy, ethynyloxy, propynyloxy and propargyloxy; R2 and R3 are independently selected from H, methyl, ethyl, vinyl, allyl, propenyl, ethynyl, propynyl and propargyl; and at least one of R1, R2 and R3 includes an unsaturated bond.

[0024] As a result, the capture of R+ substances by electrolyte additives is improved, the thickening of SEI film caused by the reduction of R+ substances in the negative electrode sheet is further inhibited, and the interfacial impedance of the negative electrode sheet is further reduced, thereby improving the capacity and cycle performance of the battery.

[0025] In any embodiment, the compound is a compound of formula III,

[0026] in,

[0027] R4 is selected from hydroxy, C1-C6 alkoxy, C2-C6 alkynyl, C2-C10 alkenyloxy and C2-C10 alkynyloxy;

[0028] R5, R6 and R7 are independently selected from H, C1-C6 alkyl, C2-C10 alkenyl and C2-C10 alkynyl;

[0029] Furthermore, at least one group among R4, R5, R6 and R7 includes an unsaturated bond.

[0030] The electrolyte additive shown in Formula III can capture the R+ substance further generated by the electrolyte oxidation decomposition products, inhibit the thickening of the SEI film caused by the reduction of R+ at the negative electrode, reduce the interfacial impedance of the negative electrode sheet, and improve the capacity, cycle performance and safety performance of the battery.

[0031] In any embodiment, in formula III, R4 is selected from hydroxyl, C1-C6 alkoxy, C2-C6 alkynyl, R5, R6 and R7 are independently selected from H, C1-C6 alkyl, a, b, c, d, e, f, g, and h are independently selected from 0, 1, 2, 3, and 4; and at least one of R4, R5, R6, and R7 includes an unsaturated bond;

[0032] Optionally, R4 is selected from hydroxy, methoxy, ethoxy, ethynyl, propargyl, vinyloxy, allyloxy, propenyloxy, ethynyloxy, propynyloxy and propargyloxy; R5, R6 and R7 are independently selected from H, methyl, ethyl, vinyl, allyl, propenyl, ethynyl, propynyl and propargyl; and at least one of R4, R5, R6 and R7 includes an unsaturated bond.

[0033] As a result, the capture of R+ substances by electrolyte additives is improved, the thickening of SEI film caused by the reduction of R+ substances in the negative electrode sheet is further inhibited, and the interfacial impedance of the negative electrode sheet is further reduced, thereby improving the capacity and cycle performance of the battery.

[0034] In any embodiment, the compound is a compound of formula IV,

[0035] in,

[0036] R8 is selected from hydroxy, C1-C6 alkoxy, C2-C6 alkynyl, C2-C10 alkenyloxy and C2-C10 alkynyloxy;

[0037] R9 and R 10 independently selected from H, C1-C6 alkyl, C2-C10 alkenyl and C2-C10 alkynyl;

[0038] Moreover, R8, R9 and R 10 At least one of the groups includes an unsaturated bond.

[0039] The electrolyte additive shown in Formula IV can capture R+ further generated by the electrolyte oxidation decomposition products, thereby inhibiting the damage of R+ to the SEI film of the negative electrode plate, reducing the interfacial impedance of the negative electrode plate, increasing the battery capacity and battery cell cycle performance, and improving the safety performance of the battery.

[0040] In any embodiment, in formula IV, R8 is selected from hydroxyl, C1-C6 alkoxy, C2-C6 alkynyl, R9 and R 10 Independently selected from H, C1-C6 alkyl, a, b, c, d, e, f, g, and h are independently selected from 0, 1, 2, 3, and 4; and R8, R9, and R 10 At least one of the groups includes an unsaturated bond;

[0041] Alternatively, in Formula IV, R8 is selected from hydroxy, methoxy, ethoxy, ethynyl, propargyl, vinyloxy, allyloxy, propenyloxy, ethynyloxy, propynyloxy and propargyloxy; R9 and R 10 are independently selected from H, methyl, ethyl, vinyl, allyl, propenyl, ethynyl, propynyl and propargyl; and R8, R9 and R 10 At least one of the groups includes an unsaturated bond.

[0042] As a result, the capture of R+ substances by electrolyte additives is improved, further inhibiting R+ from destroying the negative electrode SEI. The SEI film thickens due to continuous reduction of the electrolyte negative electrode, further reducing the interfacial impedance of the negative electrode sheet, thereby improving the capacity and cycle performance of the battery.

[0043] In any embodiment, the compound is selected from:

[0044] The above compounds are used to further inhibit R+ from destroying the negative electrode SEI. The SEI film thickens due to continuous reduction of the electrolyte negative electrode, which reduces the interfacial impedance of the negative electrode sheet, thereby improving the capacity and cycle performance of the battery.

[0045] The second aspect of the present application further provides an electrolyte comprising an electrolyte additive, wherein the electrolyte additive comprises the compound according to the first aspect of claim 1.

[0046] Therefore, the electrolyte additive used in this application can capture the R+ substance further generated by the oxidative decomposition products of the electrolyte, inhibit the reduction reaction of R+ in the negative electrode plate, thereby inhibiting the thickening of the negative electrode SEI film caused by the reduction of R+ substance, and further inhibiting the increase in the interface impedance of the negative electrode plate caused by the thickening of the SEI film, thereby improving the cycle performance, capacity and safety performance of the battery.

[0047] In any embodiment, the electrolyte additive accounts for 0.005%-25% by weight of the electrolyte, optionally 0.01%-20% by weight, more preferably 0.1%-10% by weight, and further optionally 2%-5% by weight. This can further improve the cycle performance of the battery while maintaining a high battery capacity and enhancing the battery safety performance.

[0048] The third aspect of the present application provides a battery, comprising an electrolyte additive or the electrolyte of the second aspect of the present application, wherein the electrolyte additive comprises the compound of the first aspect of the present application.

[0049] In any embodiment, the battery further comprises a positive electrode sheet, the positive electrode sheet comprises a positive electrode current collector and a positive electrode film layer provided on at least one surface of the positive electrode current collector, the positive electrode film layer comprises a positive electrode lithium supplement Li e MO g ,in,

[0050] M includes one or more elements selected from the group consisting of Ni, Co, Fe, Mn, Zn, Mg, Ca, Cu, Sn, Mo, Ru, Ir, V, Nb, and Cr;

[0051] 2≤e≤6, optionally, e is 2, 3, 4, 5 or 6;

[0052] 2≤g≤4, optionally, g is 2, 3 or 4.

[0053] Therefore, the positive electrode lithium replenisher used in this application undergoes an irreversible phase change during the first cycle of charging to produce oxygen free radicals, which may further generate oxygen. The oxygen free radicals and the possible generated oxygen cause the electrolyte to oxidatively decompose, and the decomposition products further generate R+. The electrolyte additive can effectively capture R+, further inhibiting R+ from destroying the negative electrode SEI. The SEI film thickens due to the continuous reduction of the electrolyte negative electrode, which inhibits the increase in the interfacial impedance of the negative electrode sheet, thereby improving the cycle performance, capacity and safety performance of the battery.

[0054] In any embodiment, the positive electrode lithium supplement includes one or more of Li2M1O2, Li2M2O3, Li3M3O4, Li5M4O4 and Li6M5O4, wherein M1 includes one or more elements of Ni, Co, Fe, Mn, Zn, Mg, Ca and Cu, M2 includes one or more elements of Mn, Sn, Mo, Ru and Ir, M3 includes one or more elements of V, Nb, Cr and Mo, M4 includes one or more elements of Fe, Cr, V and Mo, and M5 includes one or more elements of Co, V, Cr and Mo.

[0055] In any embodiment, in the positive electrode lithium supplement, the valence state of at least one metal element other than lithium is lower than its own highest oxidation valence state.

[0056] In any embodiment, the positive lithium supplement includes Li6CoO4, Li5FeO4, Li3VO4, Li2MoO3, Li2RuO3, Li2MnO3, Li2MnO2, Li2NiO2, Li2CuO2, Li2Cu k Ni 1- k M p O2 one or more; optionally, Li2Cu k Ni 1-p M pIn O2, 0<k<1, 0≤p<0.1.

[0057] In any embodiment, the mass proportion of the positive electrode lithium replenisher in the positive electrode film layer is 0.05%-15%, optionally 0.1%-10%, more optionally 1%-8%, and further optionally 1%-5%. Therefore, the content of the positive electrode lithium replenisher within the above range can compensate for the consumption of active lithium ions, so that the battery has a higher gram capacity. At the same time, the electrolyte additive of the present application can effectively capture R+ further generated by the oxidation decomposition products of the electrolyte, thereby effectively suppressing the thickening of the SEI film caused by the reduction of R+ at the negative electrode, suppressing the increase in the interface impedance of the negative electrode sheet, thereby improving the cycle performance, capacity and safety performance of the battery.

[0058] In any embodiment, the ratio of the mass proportion of the electrolyte additive in the electrolyte to the mass proportion of the positive electrode lithium replenisher in the positive electrode film layer is 0.00033-500, optionally 0.0025-40, and more optionally 0.04-5.

[0059] When the mass proportion of the compound in the electrolyte and the mass proportion of the positive electrode lithium replenisher in the positive electrode film layer are within the above range, the electrolyte additive can effectively capture R+ further generated by the electrolyte oxidation decomposition products, thereby effectively inhibiting the thickening of the SEI film caused by the reduction of R+ at the negative electrode, inhibiting the increase in the interface impedance of the negative electrode sheet, thereby improving the battery's cycle performance, capacity and safety performance.

[0060] In any embodiment, the positive electrode film layer further includes a positive electrode active material, and the positive electrode lithium supplement D v 50 Particle size and D of positive electrode active material v The ratio of the particle size to the particle size is 0.05-15, and can be 1-10, and more preferably 2-8.

[0061] Positive electrode lithium supplement D v 50 Particle size and positive electrode active material D v When the particle size ratio is within the above range, the contact area between the positive electrode lithium supplement and the electrolyte can be kept within a certain range, so as to improve the ion conductivity of the positive electrode sheet, thereby improving the capacity of the battery and the rate performance after storage, while also inhibiting the side reactions of the electrolyte and improving the cycle performance of the battery.

[0062] In any embodiment, the active specific surface area of ​​the positive electrode sheet is greater than 0 cm 2 / g and less than or equal to 25cm 2 / g, can be greater than 0cm 2 / g and less than or equal to 20cm 2 / g, more preferably greater than or equal to 0.5cm 2 / g and less than or equal to 20cm2 / g, further optionally greater than or equal to 2cm 2 / g and less than or equal to 10cm 2 / g.

[0063] The active specific surface area of ​​the positive electrode sheet within the above range helps to reduce the gas production during the first cycle of charging, improve the problems of black spots on the negative electrode interface and local lithium deposition on the negative electrode, thereby inhibiting the increase in the negative electrode interface impedance, improving the cycle performance of the battery, and also helping to reduce the polarization degree of the lithium-ion battery and increase the battery capacity.

[0064] A fourth aspect of the present application provides an electrical device comprising the battery of the third aspect of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] FIG1 is a schematic diagram of a secondary battery according to an embodiment of the present application.

[0066] FIG. 2 is an exploded view of the secondary battery according to the embodiment of the present application shown in FIG. 1 .

[0067] FIG3 is a schematic diagram of a battery module according to an embodiment of the present application.

[0068] FIG4 is a schematic diagram of a battery pack according to an embodiment of the present application.

[0069] FIG. 5 is an exploded view of the battery pack shown in FIG. 4 according to an embodiment of the present application.

[0070] FIG6 is a schematic diagram of an electric device using a secondary battery as a power source according to an embodiment of the present application.

[0071] Explanation of reference numerals: 1 battery pack; 2 upper case; 3 lower case; 4 battery module; 5 secondary battery; 51 housing; 52 electrode assembly; 53 top cover assembly. DETAILED DESCRIPTION

[0072] Below, with appropriate reference to the accompanying drawings, embodiments of the application of the compounds of the present application as electrolyte additives, electrolytes, batteries, and electrical devices are described in detail. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repeated descriptions of substantially identical structures may be omitted. This is to avoid unnecessary length in the following description and to facilitate understanding by those skilled in the art. In addition, the drawings and the following description are provided to enable those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0073] " range " disclosed in the present application is limited in the form of lower limit and upper limit, and given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of special range. The scope limited in this way can be to include end value or not include end value, and can be arbitrarily combined, that is, any lower limit can form a range with any upper limit combination. For example, if the scope of 60-120 and 80-110 is listed for specific parameters, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range value 1 and 2 are listed, and if the maximum range value 3,4 and 5 are listed, then the following range can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In this application, unless otherwise specified, the numerical range " ab " represents the abbreviation of any real number combination between a and b, wherein a and b are all real numbers. For example, a numerical range of "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is simply an abbreviation for these numerical combinations. Furthermore, when a parameter is expressed as an integer ≥ 2, this is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0074] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0075] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0076] Unless otherwise specified, all steps of the present application may be performed sequentially or randomly, preferably sequentially. For example, a method includes steps (a) and (b), which indicates that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, a method may further include step (c), which indicates that step (c) may be added to the method in any order, for example, the method may include steps (a), (b), and (c), or may include steps (a), (c), and (b), or may include steps (c), (a), and (b), etc.

[0077] Unless otherwise specified, the terms "include" and "comprising" used in this application may be open-ended or closed-ended. For example, "include" and "comprising" may indicate that other components not listed may also be included or that only the listed components are included.

[0078] Unless otherwise specified, the term "or" is used in this application to be inclusive. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, the condition "A or B" is satisfied if any of the following conditions are met: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0079] Unless otherwise specified, in this application, the term "C1-C6 alkyl" refers to a straight or branched chain alkyl group having 1 to 6 carbon atoms, such as C1-C4 alkyl, C1-C2 alkyl, C1 alkyl, C2 alkyl, C3 alkyl, C4 alkyl, C5 alkyl, or C6 alkyl. Specific examples include, but are not limited to, methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, and the like.

[0080] Unless otherwise specified, the term "C2-C10 alkynyl" as used herein refers to a straight or branched hydrocarbon group having 2-10 carbon atoms and at least one carbon-carbon triple bond. Examples include C2-C8 alkynyl, C2-C6 alkynyl, C2-C4 alkynyl, C2 alkynyl, C3 alkynyl, C5 alkynyl, C6 alkynyl, and C8 alkynyl. Specific examples include, but are not limited to, ethynyl, propynyl, and propargyl.

[0081] Unless otherwise specified, the term "C2-C10 alkenyl" in this application refers to a straight-chain or branched hydrocarbon group having 2-10 carbon atoms and at least one carbon-carbon double bond. For example, C2-C8 alkenyl, C2-C6 alkenyl, C2-C4 alkenyl, C2 alkenyl, C3 alkenyl, C5 alkenyl, C6 alkenyl, C7 alkenyl, or C8 alkenyl. Specific examples include, but are not limited to, ethenyl, propenyl, allyl, 1,3-butadienyl, and the like.

[0082] Unless otherwise specified, the term "C1-C6 alkoxy" as used herein refers to a group formed in the form of C1-C6 alkyl-O-, wherein "C1-C6 alkyl" is as defined above. Specific examples include, but are not limited to, methoxy, ethoxy, propoxy, isopropoxy, butoxy, 2-butoxy, isobutoxy, sec-butoxy, tert-butoxy, pentyloxy, and hexyloxy.

[0083] Unless otherwise specified, the term "C2-C10 alkenyloxy" as used herein refers to a group formed in the form of C2-C10 alkenyl-O-, wherein "C2-C10 alkenyl" is as defined above. Specific examples include, but are not limited to, vinyloxy, propenyloxy, and allyloxy.

[0084] Unless otherwise specified, the term "C2-C10 alkynyloxy" as used herein refers to a group formed in the form of C2-C10 alkynyl-O-, wherein "C2-C10 alkynyl" is as defined above. Specific examples include, but are not limited to, ethynyloxy, propynyloxy, and propargyloxy.

[0085] Unless otherwise specified, in the present application, the term "Dv50 particle size" refers to a particle size at which the cumulative volume reaches 50% from the smallest particle size side in a volume-based particle size distribution.

[0086] [Secondary battery]

[0087] Secondary batteries, also known as rechargeable batteries or storage batteries, are batteries that can be recharged to activate the active materials after discharge and continue to be used.

[0088] Typically, a secondary battery includes a positive electrode sheet, a negative electrode sheet, a separator, and an electrolyte. During the battery's charge and discharge process, active ions (such as lithium ions) are embedded and released back and forth between the positive and negative electrode sheets. The separator is set between the positive and negative electrode sheets, mainly to prevent the positive and negative electrodes from short-circuiting, while allowing active ions to pass through. The electrolyte between the positive and negative electrode sheets mainly plays the role of conducting active ions.

[0089] [Application of the compound as an electrolyte additive]

[0090] One embodiment of the present application provides the use of a compound represented by Formula I as an electrolyte additive;

[0091] in,

[0092] X is selected from O═P, Si and B;

[0093] n is selected from 3 and 4;

[0094] The n R groups are independently selected from hydroxyl, C1-C6 alkoxy, C2-C6 alkynyl, C2-C10 alkenyloxy (optionally C2-C6 alkenyloxy) and C2-C10 alkynyloxy (optionally C2-C6 alkynyloxy), and at least one of the n R groups includes an unsaturated bond.

[0095] The positive electrode lithium supplement undergoes an irreversible phase change during the first cycle of charging, generating oxygen free radicals, which may further generate oxygen. The oxygen free radicals and the oxygen that may be generated easily lead to oxidative decomposition of the electrolyte, and the oxidative decomposition products further generate R+ substances. The R+ substances are prone to undergo a reduction reaction in the negative electrode, causing the SEI film to thicken, resulting in increased interface impedance, deterioration of battery cycle performance, and even lithium plating, which also affects the battery capacity. The R+ substances may include H generated by the decomposition of the electrolyte salt caused by the decomposition of the solvent in the electrolyte. + and other by-products.

[0096] Although the mechanism is still unclear, the applicant unexpectedly discovered that the electrolyte additive of the present application can capture the R+ substance further generated by the electrolyte oxidation decomposition products, inhibit the reduction of the R+ substance in the negative electrode, thereby inhibiting the thickening of the SEI film caused by the reduction of the R+ substance, and further inhibiting the increase in interfacial impedance caused by the thickening of the SEI film, thereby improving the cycle performance of the battery and improving the capacity and safety performance of the battery.

[0097] In some embodiments, in Formula I, n R are independently selected from hydroxyl, C1-C6 alkoxy, C2-C6 alkynyl, Furthermore, at least one of the n R groups includes an unsaturated bond;

[0098] a, b, c and d are independently selected from 0, 1, 2, 3 and 4.

[0099] As a result, the thickening of the SEI film caused by the reduction of R+ substances in the negative electrode sheet is further inhibited, the interfacial impedance of the negative electrode sheet is further reduced, and the capacity and cycle performance of the battery are improved.

[0100] In some embodiments, in Formula I, n R groups are independently selected from hydroxy, methoxy, ethoxy, ethynyl, propargyl, vinyloxy, allyloxy, propenyloxy, ethynyloxy, propynyloxy, and propargyloxy, and at least one of the n R groups includes an unsaturated bond.

[0101] In some embodiments, in Formula I, n R groups are independently selected from hydroxyl, ethoxy, ethynyl, vinyloxy, allyloxy, propenyloxy, and ethynyloxy, and at least one of the n R groups includes an unsaturated bond.

[0102] In some embodiments, the compound is a compound of Formula II,

[0103] in,

[0104] R1 is selected from hydroxy, C1-C6 alkoxy, C2-C6 alkynyl, C2-C10 alkenyloxy (optionally C2-C6 alkenyloxy) and C2-C10 alkynyloxy (optionally C2-C6 alkynyloxy);

[0105] R2 and R3 are independently selected from H, C1-C6 alkyl, C2-C10 alkenyl (optionally C2-C6 alkenyl) and C2-C10 alkynyl (optionally C2-C6 alkynyl);

[0106] Furthermore, at least one group among R1, R2 and R3 includes an unsaturated bond.

[0107] The electrolyte additive shown in Formula II can capture the R+ species further generated by the electrolyte oxidation decomposition products, further inhibiting R+ from destroying the negative electrode SEI. The SEI film thickens due to the continuous reduction of the electrolyte negative electrode, reduces the interface impedance of the negative electrode, and improves the capacity, cycle performance and safety performance of the battery.

[0108] In some embodiments, in Formula II, R1 is selected from hydroxyl, C1-C6 alkoxy, C2-C6 alkynyl, R2 and R3 are independently selected from H, C1-C6 alkyl, a, b, c, d, e, f, g, and h are independently selected from 0, 1, 2, 3, and 4; and at least one of R1, R2, and R3 includes an unsaturated bond;

[0109] Optionally, in Formula II, R1 is selected from hydroxy, methoxy, ethoxy, ethynyl, propargyl, vinyloxy, allyloxy, propenyloxy, ethynyloxy, propynyloxy and propargyloxy; R2 and R3 are independently selected from H, methyl, ethyl, vinyl, allyl, propenyl, ethynyl, propynyl and propargyl; and at least one of R1, R2 and R3 includes an unsaturated bond.

[0110] As a result, the capture of R+ substances by electrolyte additives is improved, which further inhibits R+ from destroying the negative electrode SEI. The SEI film thickens due to the continuous reduction of the electrolyte negative electrode, which further reduces the interfacial impedance of the negative electrode sheet, thereby improving the capacity and cycle performance of the battery.

[0111] In some embodiments, in Formula II, R1 is selected from ethoxy, ethynyl, vinyloxy, allyloxy, propenyloxy and ethynyloxy; R2 and R3 are independently selected from H, ethyl, vinyl, allyl, propenyl and ethynyl; and at least one of R1, R2 and R3 includes an unsaturated bond.

[0112] In some embodiments, the compound is a compound of formula III,

[0113] in,

[0114] R4 is selected from hydroxy, C1-C6 alkoxy, C2-C6 alkynyl, C2-C10 alkenyloxy (optionally C2-C6 alkenyloxy) and C2-C10 alkynyloxy (optionally C2-C6 alkynyloxy);

[0115] R5, R6 and R7 are independently selected from H, C1-C6 alkyl, C2-C10 alkenyl (optionally C2-C6 alkenyl) and C2-C10 alkynyl (optionally C2-C6 alkynyl);

[0116] Furthermore, at least one group among R4, R5, R6 and R7 includes an unsaturated bond.

[0117] The electrolyte additive shown in Formula III can capture the R+ species further generated by the electrolyte oxidation decomposition products, further inhibiting R+ from destroying the negative electrode SEI. The SEI film thickens due to the continuous reduction of the electrolyte negative electrode, reduces the interfacial impedance of the negative electrode sheet, and improves the capacity, cycle performance and safety performance of the battery.

[0118] In some embodiments, in Formula III, R4 is selected from hydroxyl, C1-C6 alkoxy, C2-C6 alkynyl, R5, R6 and R7 are independently selected from H, C1-C6 alkyl, a, b, c, d, e, f, g, and h are independently selected from 0, 1, 2, 3, and 4; and at least one of R4, R5, R6, and R7 includes an unsaturated bond;

[0119] Optionally, R4 is selected from hydroxy, methoxy, ethoxy, ethynyl, propargyl, vinyloxy, allyloxy, propenyloxy, ethynyloxy, propynyloxy and propargyloxy; R5, R6 and R7 are independently selected from H, methyl, ethyl, vinyl, allyl, propenyl, ethynyl, propynyl and propargyl; and at least one of R4, R5, R6 and R7 includes an unsaturated bond.

[0120] As a result, the capture of R+ substances by electrolyte additives is improved, the thickening of SEI film caused by the reduction of R+ substances in the negative electrode sheet is further inhibited, and the interfacial impedance of the negative electrode sheet is further reduced, thereby improving the capacity and cycle performance of the battery.

[0121] In some embodiments, R4 is selected from hydroxy, ethoxy, ethynyl, vinyloxy, allyloxy and propenyloxy; R5, R6 and R7 are independently selected from H, ethyl, vinyl, allyl and propenyl; and at least one of R4, R5, R6 and R7 includes an unsaturated bond.

[0122] In some embodiments, the compound is a compound of formula IV,

[0123] in,

[0124] R8 is selected from hydroxy, C1-C6 alkoxy, C2-C6 alkynyl, C2-C10 alkenyloxy (optionally C2-C6 alkenyloxy) and C2-C10 alkynyloxy (optionally C2-C6 alkynyloxy);

[0125] R9 and R 10 Independently selected from H, C1-C6 alkyl, C2-C10 alkenyl (optionally C2-C6 alkenyl) and C2-C10 alkynyl (optionally C2-C6 alkynyl);

[0126] Moreover, R8, R9 and R 10 At least one of the groups includes an unsaturated bond.

[0127] The electrolyte additive shown in Formula IV can capture the R+ species further generated by the electrolyte oxidation decomposition products, further inhibiting R+ from destroying the negative electrode SEI. The SEI film thickens due to the continuous reduction of the electrolyte negative electrode, reduces the interfacial impedance of the negative electrode sheet, and improves the capacity, cycle performance and safety performance of the battery.

[0128] In some embodiments, in Formula IV, R8 is selected from hydroxy, C1-C6 alkoxy, C2-C6 alkynyl, R9 and R 10 Independently selected from H, C1-C6 alkyl, a, b, c, d, e, f, g, and h are independently selected from 0, 1, 2, 3, and 4; and R8, R9, and R 10 At least one of the groups includes an unsaturated bond;

[0129] Alternatively, in Formula IV, R8 is selected from hydroxy, methoxy, ethoxy, ethynyl, propargyl, vinyloxy, allyloxy, propenyloxy, ethynyloxy, propynyloxy and propargyloxy; R9 and R 10 are independently selected from H, methyl, ethyl, vinyl, allyl, propenyl, ethynyl, propynyl and propargyl; and R8, R9 and R 10 At least one of the groups includes an unsaturated bond.

[0130] As a result, the capture of R+ substances by electrolyte additives is improved, the thickening of SEI film caused by the reduction of R+ substances in the negative electrode sheet is further inhibited, and the interfacial impedance of the negative electrode sheet is further reduced, thereby improving the capacity and cycle performance of the battery.

[0131] In some embodiments, in Formula IV, R8 is selected from ethoxy, ethynyl, vinyloxy, allyloxy, and propenyloxy; R9 and R 10 are independently selected from ethyl, vinyl, allyl and propenyl; and R8, R9 and R 10 At least one of the groups includes an unsaturated bond.

[0132] In some embodiments, the structural formula of the propenyl group is

[0133] In some embodiments, the structural formula of the allyl group is

[0134] In some embodiments, the structural formula of the propynyl group is H3C-C≡C- * .

[0135] In some embodiments, the structural formula of the propargyl group is

[0136] In some embodiments, the structural formula of vinyloxy is

[0137] In some embodiments, the structural formula of the propenyloxy group is

[0138] In some embodiments, the structural formula of allyloxy is

[0139] In some embodiments, the structural formula of ethynyloxy is HC≡CO- * .

[0140] In some embodiments, the structural formula of propynyloxy is H3C-C≡CO- * .

[0141] In some embodiments, the structural formula of propargyloxy is

[0142] In some embodiments, the compound is selected from:

[0143] The numbers of the above compounds are shown in the following table.

[0144] The above compounds are used to further inhibit R+ from destroying the negative electrode SEI. The SEI film thickens due to continuous reduction of the electrolyte negative electrode, which reduces the interfacial impedance of the negative electrode sheet, thereby improving the capacity and cycle performance of the battery.

[0145] The preparation method of the compound represented by formula II of the present application (R2 and R3 are the same) refers to the following synthetic route:

[0146] Wherein, R1 and R2 are as defined above.

[0147] The preparation method of the compound represented by formula III of the present application refers to the following synthetic route:

[0148] Wherein, R4, R5, R6 and R7 are as defined above.

[0149] The preparation method of the compound represented by formula IV of the present application refers to the following synthetic route:

[0150] Among them, R8, R9 and R 10 The definition of is as described above.

[0151] There is no particular limitation on the solvent used in the above preparation method, as long as it does not hinder the reaction. Examples include, but are not limited to, ether solvents such as diethyl ether, tetrahydrofuran, and dioxane, and halogenated hydrocarbons.

[0152] The reaction temperature and time used in the above preparation method are determined by the properties of the reaction raw materials and solvent. The reaction temperature can usually be in the range of 20°C-100°C, and the reaction time can usually be in the range of 0.5h-48h.

[0153] The reaction raw materials used in the above preparation method are mostly conventional raw materials and can be directly purchased from the market.

[0154] The application of the aforementioned compound in the present application in an electrolyte or a battery; optionally, the electrolyte is an electrolyte for a battery containing a positive electrode lithium replenisher; optionally, the battery is a battery containing a positive electrode lithium replenisher.

[0155] [Electrolytes]

[0156] The present application provides an electrolyte comprising an electrolyte additive, wherein the electrolyte additive includes the aforementioned compound.

[0157] Therefore, the electrolyte additive used in this application can capture the R+ substance further generated by the oxidative decomposition products of the electrolyte, inhibit R+ from destroying the negative electrode SEI, and the thickening of the SEI film caused by the continuous reduction of the electrolyte negative electrode, thereby inhibiting the increase in the interface impedance of the negative electrode sheet caused by the thickening of the SEI film, thereby improving the cycle performance, capacity and safety performance of the battery.

[0158] In some embodiments, the electrolyte additive is added to the electrolyte by methods including, but not limited to, actively adding to the electrolyte, dissolving or seeping from the positive electrode into the electrolyte, dissolving or seeping from the negative electrode into the electrolyte, and dissolving or seeping from the separator into the electrolyte.

[0159] In some embodiments, the mass proportion W1 of the electrolyte additive in the electrolyte is 0.005%-25%, optionally 0.01%-20%, more optionally 0.1%-10%, and further optionally 2%-5%. This can further improve the cycle performance of the battery while maintaining a high battery capacity and enhancing the battery safety performance.

[0160] The electrolyte conducts ions between the positive and negative electrodes. For example, the electrolyte can be liquid, gel, or solid.

[0161] In some embodiments, the electrolyte is liquid.

[0162] In some embodiments, the electrolyte further comprises an electrolyte salt and a solvent.

[0163] In some embodiments, the type of electrolyte salt is not particularly limited and can be selected according to actual needs. Specifically, the electrolyte salt can be selected from LiN(C x F 2x+1 SO2)(C y F 2y+1 SO2), LiPF6, LiBF4, LiBOB, LiAsF6, Li(FSO2)2N, LiCF3SO3, and LiClO4, where x and y are natural numbers. The concentration range of the electrolyte salt is 0.5M to 2.5M, and can be optionally 0.7M to 2M.

[0164] In some embodiments, the type of solvent is not particularly limited and can be selected according to actual needs. Specifically, the solvent can also include one or more of other types of linear carbonates, cyclic carbonates, and carboxylates. Wherein, the type of linear carbonates, cyclic carbonates, and carboxylates is not specifically limited and can be selected according to actual needs. Preferably, the solvent can also include one or more of diethyl carbonate, dipropyl carbonate, ethyl methyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, ethylene carbonate, propylene carbonate, butylene carbonate, gamma-butyrolactone, methyl formate, ethyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, methyl propionate, and tetrahydrofuran.

[0165] In some embodiments, the electrolyte additives may optionally include additives with other functions, such as negative electrode film-forming additives, positive electrode film-forming additives, additives for improving battery overcharge performance, and additives for improving battery high or low temperature performance.

[0166] [Positive electrode]

[0167] The positive electrode sheet generally includes a positive electrode current collector and a positive electrode film layer provided on at least one surface of the positive electrode current collector, wherein the positive electrode film layer includes a positive electrode lithium supplement Li e MO g , wherein M includes one or more elements selected from the group consisting of Ni, Co, Fe, Mn, Zn, Mg, Ca, Cu, Sn, Mo, Ru, Ir, V, Nb, and Cr;

[0168] 2≤e≤6, optionally, e is 2, 3, 4, 5, or 6, and e can also be a decimal in the range of 2-6;

[0169] 2≤g≤4, optionally, g is 2, 3 or 4, and g can also be a decimal in the range of 2-4.

[0170] Therefore, the positive electrode lithium supplement agent used in this application undergoes an irreversible phase change during the first cycle of charging to produce oxygen free radicals, which may further generate oxygen. The oxygen free radicals and the possible generated oxygen cause the electrolyte to oxidatively decompose, and the decomposition products further generate R+. The electrolyte additive can effectively capture R+, inhibit the SEI film thickening caused by the continuous reduction of the electrolyte negative electrode caused by the destruction of the negative electrode SEI by R+, and inhibit the increase in the interface impedance of the negative electrode sheet, thereby improving the cycle performance, capacity and safety performance of the battery.

[0171] As an example, the positive electrode current collector has two surfaces opposite to each other in its thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive electrode current collector.

[0172] In some embodiments, the positive electrode current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer material base and a metal layer formed on at least one surface of the polymer material base. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0173] In some embodiments, the positive electrode lithium supplement includes one or more of Li2M1O2, Li2M2O3, Li3M3O4, Li5M4O4 and Li6M5O4, wherein M1 includes one or more elements of Ni, Co, Fe, Mn, Zn, Mg, Ca and Cu, M2 includes one or more elements of Mn, Sn, Mo, Ru and Ir, M3 includes one or more elements of V, Nb, Cr and Mo, M4 includes one or more elements of Fe, Cr, V and Mo, and M5 includes one or more elements of Co, V, Cr and Mo.

[0174] In some embodiments, in the positive electrode lithium supplement, the valence state of at least one metal element other than lithium is lower than its highest oxidation state.

[0175] In some embodiments, the highest oxidation state refers to the valence state obtained by losing or transferring all of the valence electrons (or outermost electrons) of an element.

[0176] In some embodiments, the positive lithium supplement includes Li6CoO4, Li5FeO4, Li3VO4, Li2MoO3, Li2RuO3, Li2MnO3, Li2MnO2, Li2NiO2, Li2CuO2, Li2Cu k Ni 1- k M p O2 one or more; optionally, Li2Cu k Ni 1-p M p In O2, 0<k<1, 0≤p<0.1.

[0177] In some embodiments, the mass proportion W2 of the positive electrode lithium supplement in the positive electrode film layer is 0.05%-15%, optionally 0.1%-10%, more optionally 1%-8%, and further optionally 1%-5%, for example, it can be 0.05%, 0.08%, 0.1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15% and the range of any of the above values.

[0178] Therefore, the content of the positive electrode lithium replenisher is within the above range, which can make up for the consumption of active lithium ions and make the battery have a higher gram capacity. At the same time, the electrolyte additive of the present application can effectively capture R+ further generated by the oxidation decomposition products of the electrolyte, thereby effectively inhibiting R+ from destroying the negative electrode SEI. The SEI film thickens due to the continuous reduction of the electrolyte negative electrode, which inhibits the increase of the interface impedance of the negative electrode sheet, thereby improving the cycle performance, capacity and safety performance of the battery.

[0179] In some embodiments, the mass ratio W1 of the electrolyte additive in the electrolyte and the mass ratio W2 of the positive electrode lithium supplement in the positive electrode film layer satisfy the following relationship: 0.00033≤W1 / W2≤500, optionally 0.0025≤W1 / W2≤40, more optionally 0.04≤W1 / W2≤5, W1 / W2 can be, for example, 0.00033, 0.001, 0.003, 0.005, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 10, 13, 15, 20, 25, 30, 40, 45, 50, and any range consisting of the above values.

[0180] When the mass proportion of the compound in the electrolyte and the mass proportion of the positive electrode lithium replenisher in the positive electrode film layer are within the above range, the electrolyte additive can effectively capture R+ further generated by the electrolyte oxidation decomposition products, thereby effectively inhibiting the thickening of the SEI film caused by the reduction of R+ at the negative electrode, inhibiting the increase in the interface impedance of the negative electrode sheet, thereby improving the battery's cycle performance, capacity and safety performance.

[0181] In some embodiments, the positive electrode film layer further comprises a positive electrode active material, and the D v 50 Particle size and D of positive electrode active material v The ratio of particle size to particle size is 0.05-15, and can be 1-10, or more preferably 2-8. For example, it can be 0.05, 0.07, 0.1, 0.5, 0.8, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, or any range thereof.

[0182] Positive electrode lithium supplement D v 50 Particle size and positive electrode active material D v When the particle size ratio is within the above range, the contact area between the positive electrode lithium supplement and the electrolyte can be kept within a certain range, so as to improve the ion conductivity of the positive electrode sheet, thereby improving the capacity of the battery and the rate performance after storage, while also inhibiting the side reactions of the electrolyte and improving the cycle performance of the battery.

[0183] In some embodiments, Dv The particle size can be measured by common methods in the art; for example, according to the method in GB / T 19077-2016 "Particle size distribution by laser diffraction method", the instrument used can be a laser particle size analyzer.

[0184] In some embodiments, the active specific surface area of ​​the positive electrode sheet is greater than 0 cm 2 / g and less than or equal to 25cm 2 / g, can be greater than 0cm 2 / g and less than or equal to 20cm 2 / g, more preferably greater than or equal to 0.5cm 2 / g and less than or equal to 20cm 2 / g, further optionally greater than or equal to 2cm 2 / g and less than or equal to 10cm 2 / g, for example, 0.01 cm 2 / g, 0.05cm 2 / g, 0.08cm 2 / g, 0.1cm 2 / g, 0.2cm 2 / g, 0.3cm 2 / g, 0.5cm 2 / g, 0.7cm 2 / g, 1cm 2 / g, 2cm 2 / g, 3cm 2 / g, 4cm 2 / g, 5cm 2 / g、6cm 2 / g、8cm 2 / g, 10cm 2 / g, 12cm 2 / g, 13cm 2 / g, 15cm 2 / g, 17cm 2 / g, 19cm 2 / g, 20cm 2 / g, 21cm 2 / g, 23cm 2 / g, 24cm 2 / g, 25cm 2 / g and any range consisting of the above numerical values.

[0185] The active specific surface area of ​​the positive electrode sheet within the above range helps to reduce the gas production during the first cycle of charging, improve the problems of black spots on the negative electrode interface and local lithium deposition on the negative electrode, thereby inhibiting the increase in the negative electrode interface impedance, improving the cycle performance of the battery, and also helping to reduce the polarization degree of the lithium-ion battery and increase the battery capacity.

[0186] In some embodiments, the active specific surface area of ​​the positive electrode sheet is the ratio of the active surface area of ​​the positive electrode sheet to the weight of the positive electrode sheet, and the unit can be, for example, cm 2 The active surface area of ​​the positive electrode refers to the effective active surface area on the positive electrode, which is generally measured by introducing an electrochemical redox couple as a probe molecule and measuring the electrochemical behavior.

[0187] In some embodiments, the testing method for the active surface area of ​​the positive electrode is generally as follows: when a certain potential is applied, electrons are transferred to the active sites on the surface of the positive electrode active material in the positive electrode plate through the current collector, and then the probe molecules undergo an oxidation-reduction reaction; by testing the cyclic voltammetry curve of the probe molecules at different scan rates on the surface of the positive electrode active material, the oxidation peak current and the reduction peak current are obtained, and the slope is obtained by fitting the oxidation peak current or the reduction peak current with the scan rate, and the active surface area of ​​the positive electrode plate is calculated according to the Randles-Sevick equation.

[0188] Specifically, the test method for the active surface area of ​​the positive electrode is as follows: the positive electrode plate to be tested, the negative electrode plate and the electrolyte containing the probe molecule are assembled into a button half-cell; in a room temperature environment, the button half-cell is tested using a Chenhua electrochemical workstation (model CHI660E) at different scan rates V in the range of 0.01mV / s to 3.50mV / s, and the scanning voltage range is 2.9V to 3.5V, and a series of oxidation peak current i p (oxidation) and reduction peak current i p (reduction); the square root of the scan rate V is used as the X-axis, and a series of oxidation peak currents i p As the Y axis, the slope K is obtained. According to the Randles Sevick equation i p =2.69×10 5 ×n 2 / 3 ×c×D 1 / 2 ×A×V 1 / 2 , we get the slope K = 2.69 × 10 5 ×n 2 / 3 ×c×D 1 / 2 ×A; where n is the number of electron transfers associated with the probe molecule type, and in this test method, n is 1; D is the diffusion coefficient, and in this test method, D is 2.1×10 -6 cm 2 / s; A is the active surface area of ​​the positive electrode; c is the concentration of probe molecules in the electrolyte. The active surface area A of the positive electrode is calculated according to the above formula.

[0189] The electrolyte in the above test method is a common electrolyte. For example, ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) can be mixed in a volume ratio of 1:1:1, and then the fully dried lithium salt LiPF6 is dissolved in a mixed organic solvent at a ratio of 1 mol / L.

[0190] The redox potential of the probe molecule in the above test method may be, for example, 2 V to 4 V. The concentration of the probe molecule may be, for example, 0.03 mol / L to 0.08 mol / L, and may be 0.05 mol / L.

[0191] In the above test method, the probe molecules include but are not limited to hexaammoniumruthenium, ferric chloride, and ferrocene.

[0192] In some embodiments, the positive electrode active material may adopt the positive electrode active material for batteries that is well known in the art. As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates with an olivine structure, lithium transition metal oxides, and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05O2) and its modified compounds. Examples of olivine-structured lithium-containing phosphates may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon.

[0193] In some embodiments, the positive electrode film layer may further optionally include a binder. As an example, the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), a vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, a tetrafluoroethylene-hexafluoropropylene copolymer, and a fluorine-containing acrylate resin.

[0194] In some embodiments, the positive electrode film layer may further include a conductive agent. For example, the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0195] In some embodiments, the positive electrode sheet can be prepared by the following method: the components for preparing the positive electrode sheet, such as the positive electrode active material, the conductive agent, the binder and any other components, are dispersed in a solvent (such as N-methylpyrrolidone) to form a positive electrode slurry; the positive electrode slurry is coated on the positive electrode current collector, and after drying, cold pressing and other processes, the positive electrode sheet can be obtained.

[0196] [Negative electrode]

[0197] The negative electrode sheet includes a negative electrode current collector and a negative electrode film layer provided on at least one surface of the negative electrode current collector, wherein the negative electrode film layer includes a negative electrode active material.

[0198] As an example, the negative electrode current collector has two surfaces opposite to each other in its thickness direction, and the negative electrode film layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0199] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. The composite current collector may include a polymer base layer and a metal layer formed on at least one surface of the polymer base material. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer base material (such as a base material of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0200] In some embodiments, the negative electrode active material may be a negative electrode active material for a battery that is well known in the art. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate. The silicon-based material may be selected from at least one of elemental silicon, silicon oxides, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxides, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0201] In some embodiments, the negative electrode film layer may further include a binder. For example, the binder may be selected from at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0202] In some embodiments, the negative electrode film layer may further include a conductive agent. For example, the conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0203] In some embodiments, the negative electrode film layer may optionally include other additives, such as a thickener (eg, sodium carboxymethyl cellulose (CMC-Na)).

[0204] In some embodiments, the negative electrode sheet can be prepared by the following method: the components for preparing the negative electrode sheet, such as the negative electrode active material, the conductive agent, the binder and any other components, are dispersed in a solvent (such as deionized water) to form a negative electrode slurry; the negative electrode slurry is coated on the negative electrode current collector, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained.

[0205] [Isolation film]

[0206] In some embodiments, the secondary battery further includes a separator. The present application has no particular limitation on the type of separator, and any known porous separator with good chemical and mechanical stability can be selected.

[0207] In some embodiments, the material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.

[0208] In some embodiments, the positive electrode sheet, the negative electrode sheet, and the separator can be formed into an electrode assembly through a winding process or a lamination process.

[0209] In some embodiments, the secondary battery may include an outer packaging that can be used to encapsulate the electrode assembly and the electrolyte.

[0210] In some embodiments, the outer packaging of the secondary battery can be a hard shell, such as a hard plastic shell, an aluminum shell, or a steel shell. Alternatively, the outer packaging of the secondary battery can be a soft shell, such as a pouch-type soft shell. The soft shell can be made of plastic, such as polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0211] The present application has no particular limitation on the shape of the secondary battery, which may be cylindrical, square, or any other shape. For example, FIG1 shows a secondary battery 5 with a square structure as an example.

[0212] In some embodiments, referring to FIG2 , the outer package may include a shell 51 and a cover plate 53. The shell 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity. The shell 51 has an opening connected to the receiving cavity, and the cover plate 53 can be covered on the opening to close the receiving cavity. The positive electrode sheet, the negative electrode sheet and the isolation membrane can be formed into an electrode assembly 52 through a winding process or a lamination process. The electrode assembly 52 is encapsulated in the receiving cavity. The electrolyte is infiltrated in the electrode assembly 52. ​​The number of electrode assemblies 52 contained in the secondary battery 5 can be one or more, and those skilled in the art can select according to specific actual needs.

[0213] In some embodiments, secondary batteries can be assembled into a battery module. The number of secondary batteries contained in the battery module can be one or more. The specific number can be selected by those skilled in the art according to the application and capacity of the battery module.

[0214] Figure 3 shows an example battery module 4. Referring to Figure 3 , within the battery module 4, multiple secondary batteries 5 may be arranged sequentially along the length of the battery module 4. Of course, any other arrangement is also possible. Furthermore, the multiple secondary batteries 5 may be secured together using fasteners.

[0215] Optionally, the battery module 4 may further include a housing having a receiving space, and the plurality of secondary batteries 5 are received in the receiving space.

[0216] In some embodiments, the battery modules described above may also be assembled into a battery pack. The battery pack may contain one or more battery modules, and the specific number may be selected by those skilled in the art based on the application and capacity of the battery pack.

[0217] Figures 4 and 5 illustrate an example battery pack 1. Referring to Figures 4 and 5 , the battery pack 1 may include a battery box and multiple battery modules 4 disposed within the battery box. The battery box comprises an upper case 2 and a lower case 3. The upper case 2 can be placed over the lower case 3 to form an enclosed space for accommodating the battery modules 4. The multiple battery modules 4 can be arranged in any manner within the battery box.

[0218] In addition, the present application also provides an electrical device, which includes at least one of the secondary battery, battery module, or battery pack provided in the present application. The secondary battery, battery module, or battery pack can be used as a power source for the electrical device, or as an energy storage unit for the electrical device. The electrical device may include mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but is not limited thereto.

[0219] As an electrical device, a secondary battery, a battery module or a battery pack can be selected according to its usage requirements.

[0220] Figure 6 shows an example of an electric device. This device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the high power and high energy density requirements of the secondary battery, a battery pack or battery module can be used.

[0221] [Example]

[0222] Below, the embodiment of the present application is described. The embodiment described below is exemplary and is only used to explain the present application, and is not to be construed as limiting the present application. Where specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. Reagents or instruments used that do not specify the manufacturer are conventional products that can be obtained commercially.

[0223] Example 1

[0224] 1. Preparation of positive electrode sheet: Lithium iron phosphate, positive electrode active material, and Li2Cu 0.6 Ni 0.4 O2, binder polyvinylidene fluoride (PVDF), and conductive agent acetylene black are dissolved in solvent N-methylpyrrolidone (NMP) in a mass ratio of 95:2:2:1, and are fully stirred and mixed to prepare a positive electrode slurry; the positive electrode slurry is evenly coated on the positive electrode current collector aluminum foil, and then dried, cold pressed, and cut to obtain the positive electrode sheet.

[0225] 2. Preparation of negative electrode sheets: Dissolve the negative electrode active material artificial graphite, conductive agent acetylene black, binder styrene-butadiene rubber (SBR), and thickener sodium carboxymethyl cellulose (CMC-Na) in deionized water at a mass ratio of 95:2:2:1, stir and mix thoroughly to prepare a negative electrode slurry; coat the negative electrode slurry on the negative electrode current collector copper foil, and then dry, cold press, and cut to obtain the negative electrode sheet.

[0226] 3. Isolation film: polypropylene film.

[0227] 4. Preparation of electrolyte: In an argon atmosphere glove box (H2O <0.1ppm, O2 <0.1ppm), ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DEC) were mixed in a volume ratio of 1:1:1. LiPF6 was then uniformly dissolved in the above solution, and compound 1-1 was added to obtain an electrolyte. The concentration of LiPF6 in the electrolyte was 1 mol / L, and the weight proportion of compound 1-1 in the electrolyte was 2%.

[0228] 5. Preparation of secondary batteries: stack the positive electrode sheet, separator, and negative electrode sheet in order, so that the separator is between the positive and negative electrode sheets to play an isolating role, and then wind them to obtain the electrode assembly; place the electrode assembly in the battery case, inject the electrolyte after drying, and then make the secondary battery through processes such as formation and static standing.

[0229] The secondary battery preparation methods of Examples 2-53 and Comparative Examples 1-2 are similar to those of Example 1. The different product parameters are detailed in Table 1.

[0230] Positive electrode lithium supplement Li2Cu 0.6 Ni 0.4 Preparation of O2:

[0231] Li2O, NiO, and CuO powders were weighed and ball-milled to achieve a uniform mixing ratio of Li, Ni, and Cu in the mixed powder. The molar ratio of Li, Ni, and Cu in the mixed powder was 2.05:0.4:0.6. The mixed powder was heated to 680°C in a nitrogen atmosphere at a heating rate of 3°C / min, held for 10 hours, and then naturally cooled. The sintered product was crushed and graded to obtain a graded product with a Dv50 particle size of 5 μm. The graded product was washed with anhydrous ethanol for 0.5 hours and dried in a forced air oven at 160°C for 12 hours.

[0232] Preparation of positive electrode lithium supplement Li2CuO2:

[0233] Except for not adding NiO and the molar ratio of Li and Cu elements in the mixed powder being 2.05:1, the others are the same as the positive electrode lithium supplement Li2Cu 0.6 Ni 0.4 The preparation method of O2 is the same.

[0234] Preparation of positive electrode lithium supplement Li2NiO2:

[0235] The nickel-based precursor Ni(OH)2 was obtained by coprecipitation. The precursor Ni(OH)2 and lithium oxide Li2O (purity >97%, Aldrich) were ball-milled at a molar ratio of Li / Ni = 3:1 for 5 hours at 500 rpm to obtain a mixed powder. The mixed powder was sintered in a nitrogen atmosphere at 250°C for 2 hours, 450°C for 2 hours, and then raised to 700°C at a heating rate of 1°C / min and sintered for 10 hours.

[0236] Preparation of positive electrode lithium supplement Li5FeO4:

[0237] Lithium oxide (purity >97%, Aldrich) and iron oxide (purity >99%, Aldrich) were mixed at a Li / Fe molar ratio of 5:1, pretreated at 450°C for 8 h under argon atmosphere, ground evenly, and then heated to 750°C at a rate of 5°C / min. The mixture was sintered at this temperature for 18 h and naturally cooled to room temperature.

[0238] Preparation of positive electrode lithium supplement Li6CoO4:

[0239] In a dry room, lithium oxide (purity >97%, Aldrich) and cobalt oxide (purity >99%, Aldrich) were mixed with a Li / Co elemental molar ratio of 6:1, ball-milled for 12 h, calcined at 700 °C for 12 h in an argon atmosphere, and naturally cooled to room temperature.

[0240] Test Case

[0241] (1) Dv50 particle size test:

[0242] According to GB / T 19077-2016 “Particle size distribution by laser diffraction method”, the particle size was determined using a Mastersizer 2000E laser particle size analyzer from Malvern Instruments Ltd., UK.

[0243] (2) Test of active specific surface area of ​​positive electrode:

[0244] ①Materials and reagents:

[0245] The negative electrode is a metal lithium sheet with a thickness of 0.4mm;

[0246] Preparation of the electrolyte: Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) are mixed in a volume ratio of 1:1:1, and then fully dried LiPF6 and the probe molecule ferrocene are dissolved in the mixed organic solvent to obtain an electrolyte with a LiPF6 concentration of 1 mol / L and a probe molecule concentration c of 0.05 mol / L; the redox potential of the probe molecule is 2V~4V.

[0247] ②Test method:

[0248] The positive electrode to be tested, the above-mentioned negative electrode and the electrolyte were assembled into a button half-cell; at room temperature, the button half-cell was tested using a Chenhua electrochemical workstation (model CHI660E) at different scan rates V in the range of 0.01mV / s to 3.50mV / s, and the scanning voltage range was 2.9V to 3.5V, and a series of oxidation peak currents i p (oxidation) and reduction peak current i p (reduction); the square root of the scan rate V is used as the X-axis, and a series of oxidation peak currents i p As the Y axis, the slope K is obtained. According to the Randles Sevick equation i p =2.69×10 5 ×n 2 / 3 ×c×D 1 / 2 ×A×V 1 / 2 , we get the slope K = 2.69 × 10 5 ×n 2 / 3 ×c×D 1 / 2 ×A; where n is the number of electron transfers associated with the probe molecule type, and in this test method, n is 1; D is the diffusion coefficient, and in this test method, D is 2.1×10 -6 cm 2 / s; A is the active surface area of ​​the positive electrode; c is the concentration of probe molecules in the electrolyte. The active surface area A of the positive electrode is calculated using the above formula. The active specific surface area of ​​the positive electrode is then calculated by dividing the active surface area A by the weight m of the positive electrode.

[0249] (3) Battery capacity test:

[0250] At 25°C, the battery was charged at a constant current of 0.33C to 3.65V, then charged at a constant voltage of 3.65V until the current was less than 0.05C. The lithium-ion battery was then discharged at a constant current of 0.33C to 2.5V, and its discharge capacity was recorded as C0 (mAh). The gram capacity of the battery is C0 / W3 (mAh / g), where W3 is the total mass (g) of the positive electrode active material and the positive electrode lithium supplement.

[0251] (4) Battery 45℃ cycle performance test:

[0252] At 45°C, charge the battery at a constant current of 1C to a voltage of 3.65V, then charge at a constant voltage of 3.65V to a current ≤ 0.05C, and then discharge the battery at a constant current of 1C to a voltage of 2.5V. This is one charge and discharge process, and the discharge capacity at this time is recorded as the discharge capacity of the battery's first cycle. Repeat the charge and discharge cycles in this way, calculate the battery cycle capacity retention rate according to the following formula, and record the number of cycles corresponding to the cycle capacity retention rate reaching 80%.

[0253] Battery cycle capacity retention rate (%) = (discharge capacity of the battery at the Nth cycle / discharge capacity of the battery at the first cycle) × 100%

[0254] (5) Test of the anode EIS impedance growth rate after the battery is cycled 50 times at 45°C:

[0255] Before the cycle test, the battery was charged to 50% SOC and then disassembled. The negative electrode plate was removed and assembled into a button half-cell of negative electrode, electrolyte and lithium plate. The button half-cell was placed on the electrochemical workstation, and the impedance curve was tested using an EIS impedance tester. The anode interface SEI film impedance R0 was calculated by the equivalent circuit fitting method. The test frequency range was 0.01-10kHz, and the disturbance voltage was set to 10mV.

[0256] At 45°C, the lithium-ion battery is charged at a constant current of 1C to a voltage of 3.65V, then charged at a constant voltage of 3.65V to a current ≤ 0.05C, and then the battery is discharged at a constant current of 1C to a voltage of 2.5V. This is a charge and discharge process. The lithium-ion battery is cycled 50 times according to this process, and then the negative electrode plate is disassembled according to the above method and the anode interface SEI film impedance Rt is tested after 50 cycles. The impedance growth rate is calculated according to the following formula.

[0257] Impedance growth rate (%) = 100% × (Rt-R0) / R0

[0258] Table 2: Performance test results of Examples 1-53 and Comparative Examples 1-2

[0259] From Table 2 we can see that:

[0260] Compared with Comparative Examples 1-2, the negative electrode interface impedance growth rate of the battery of the present application is significantly reduced, the battery capacity is significantly improved, and the battery cycle life is significantly extended.

[0261] Compared with Examples 40-41, the battery negative electrode interface impedance growth rate of Examples 2, 29-32, and 37-39 of the present application is significantly lower, the battery capacity is significantly higher, and the battery cycle life is significantly longer.

[0262] Compared with Example 42, the battery capacity of Examples 2 and 24-28 of the present application is significantly higher and the battery cycle life is significantly longer. Compared with Example 43, the growth rate of the negative electrode interface impedance of the battery of Examples 2 and 24-28 of the present application is significantly reduced and the battery cycle life is significantly longer.

[0263] Compared with Examples 52-53, the battery capacity of Examples 2 and 49-51 of the present application is significantly higher and the battery cycle life is significantly longer.

[0264] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the present application, any other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. Use of the compound represented by formula I as an electrolyte additive; in, Said X is selected from O=P, Si and B; The n is selected from 3 and 4; The n R groups are independently selected from hydroxyl, C1-C6 alkoxy, C2-C6 alkynyl, C2-C10 alkenyloxy and C2-C10 alkynyloxy, and at least one of the n R groups includes an unsaturated bond.

2. The use according to claim 1, wherein: n said R are independently selected from hydroxyl, C1-C6 alkoxy, C2-C6 alkynyl, Furthermore, at least one of the n R groups includes an unsaturated bond; The a, b, c and d are independently selected from 0, 1, 2, 3 and 4.

3. The use according to claim 1 or 2, wherein: The n R groups are independently selected from hydroxy, methoxy, ethoxy, ethynyl, propargyl, vinyloxy, allyloxy, propenyloxy, ethynyloxy, propynyloxy and propargyloxy, and at least one of the n R groups includes an unsaturated bond.

4. The use according to claim 1, wherein: The compound is a compound represented by formula II, in, The R1 is selected from hydroxyl, C1-C6 alkoxy, C2-C6 alkynyl, C2-C10 alkenyloxy and C2-C10 alkynyloxy; Said R2 and R3 are independently selected from H, C1-C6 alkyl, C2-C10 alkenyl and C2-C10 alkynyl; Furthermore, at least one of the groups of R1, R2 and R3 includes an unsaturated bond.

5. The use according to claim 4, wherein: The R1 is selected from hydroxyl, C1-C6 alkoxy, C2-C6 alkynyl, The R2 and R3 are independently selected from H, C1-C6 alkyl, The a, b, c, d, e, f, g and h are independently selected from 0, 1, 2, 3 and 4; and at least one of the R1, R2 and R3 includes an unsaturated bond; Optionally, R1 is selected from hydroxy, methoxy, ethoxy, ethynyl, propargyl, vinyloxy, allyloxy, propenyloxy, ethynyloxy, propynyloxy and propargyloxy; R2 and R3 are independently selected from H, methyl, ethyl, vinyl, allyl, propenyl, ethynyl, propynyl and propargyl; and at least one of R1, R2 and R3 includes an unsaturated bond.

6. The use according to claim 1, wherein: The compound is a compound represented by formula III, in, The R4 is selected from hydroxyl, C1-C6 alkoxy, C2-C6 alkynyl, C2-C10 alkenyloxy and C2-C10 alkynyloxy; Said R5, R6 and R7 are independently selected from H, C1-C6 alkyl, C2-C10 alkenyl and C2-C10 alkynyl; Furthermore, at least one of the groups of R4, R5, R6 and R7 includes an unsaturated bond.

7. The use according to claim 6, wherein: The R4 is selected from hydroxyl, C1-C6 alkoxy, C2-C6 alkynyl, The R5, R6 and R7 are independently selected from H, C1-C6 alkyl, The a, b, c, d, e, f, g and h are independently selected from 0, 1, 2, 3 and 4; and at least one of the R4, R5, R6 and R7 includes an unsaturated bond; Optionally, R4 is selected from hydroxy, methoxy, ethoxy, ethynyl, propargyl, vinyloxy, allyloxy, propenyloxy, ethynyloxy, propynyloxy and propargyloxy; R5, R6 and R7 are independently selected from H, methyl, ethyl, vinyl, allyl, propenyl, ethynyl, propynyl and propargyl; and at least one of R4, R5, R6 and R7 includes an unsaturated bond.

8. The use according to claim 1, wherein: The compound is a compound represented by formula IV, in, The R8 is selected from hydroxyl, C1-C6 alkoxy, C2-C6 alkynyl, C2-C10 alkenyloxy and C2-C10 alkynyloxy; The R9 and R 10 Independently selected from H, C1-C6 alkyl, C2-C10 alkenyl and C2-C10 alkynyl; Furthermore, R8, R9 and R 10 At least one of the groups includes an unsaturated bond.

9. The use according to claim 8, wherein: The R8 is selected from hydroxyl, C1-C6 alkoxy, C2-C6 alkynyl, The R9 and R 10 Independently selected from H, C1-C6 alkyl, The a, b, c, d, e, f, g and h are independently selected from 0, 1, 2, 3 and 4; and the R8, R9 and R 10 At least one of the groups includes an unsaturated bond; Optionally, the R8 is selected from hydroxy, methoxy, ethoxy, ethynyl, propargyl, vinyloxy, allyloxy, propenyloxy, ethynyloxy, propynyloxy and propargyloxy; the R9 and R 10 are independently selected from H, methyl, ethyl, vinyl, allyl, propenyl, ethynyl, propynyl and propargyl; and, said R8, R9 and R 10 At least one of the groups includes an unsaturated bond.

10. The use according to any one of claims 1 to 9, wherein: The compound is selected from:

11. An electrolyte comprising an electrolyte additive, wherein the electrolyte additive comprises the compound as claimed in any one of claims 1 to 10.

12. The electrolyte according to claim 11, wherein The mass proportion of the electrolyte additive in the electrolyte is 0.005%-25%, optionally 0.01%-20%, more optionally 0.1%-10%, further optionally 2%-5%.

13. A battery comprising an electrolyte additive or the electrolyte according to claim 11 or 12, wherein: The electrolyte additive comprises the compound described in any one of claims 1 to 10.

14. The battery according to claim 13, further comprising a positive electrode plate, the positive electrode plate comprising a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector, the positive electrode film layer comprising a positive electrode lithium supplement Li e MO g ,in, The M includes one or more elements selected from the group consisting of Ni, Co, Fe, Mn, Zn, Mg, Ca, Cu, Sn, Mo, Ru, Ir, V, Nb and Cr; 2≤e≤6, optionally, e is 2, 3, 4, 5 or 6; 2≤g≤4, optionally, g is 2, 3 or 4.

15. The battery according to claim 14, wherein The positive electrode lithium supplement includes one or more of Li2M1O2, Li2M2O3, Li3M3O4, Li5M4O4 and Li6M5O4, wherein M1 includes one or more elements of Ni, Co, Fe, Mn, Zn, Mg, Ca and Cu, M2 includes one or more elements of Mn, Sn, Mo, Ru and Ir, M3 includes one or more elements of V, Nb, Cr and Mo, M4 includes one or more elements of Fe, Cr, V and Mo, and M5 includes one or more elements of Co, V, Cr and Mo.

16. The battery according to claim 14 or 15, wherein: In the positive electrode lithium supplement, the valence state of at least one metal element other than lithium is lower than its own highest oxidation valence state.

17. The battery according to any one of claims 14 to 16, wherein The positive electrode lithium supplement is selected from Li6CoO4, Li5FeO4, Li3VO4, Li2MoO3, Li2RuO3, Li2MnO3, Li2MnO2, Li2NiO2, Li2CuO2 and Li2Cu k Ni 1-p M p One or more of O2; Optionally, the Li2Cu k Ni 1-p M p In O2, 0<k<1, 0≤p<0.

1.

18. The battery according to any one of claims 14 to 17, wherein The mass proportion of the positive electrode lithium supplement in the positive electrode film layer is 0.05%-15%, optionally 0.1%-10%, more optionally 1%-8%, further optionally 1%-5%.

19. The battery according to any one of claims 14 to 18, wherein The ratio of the mass proportion of the electrolyte additive in the electrolyte to the mass proportion of the positive electrode lithium supplement in the positive electrode film layer is 0.00033-500, optionally 0.0025-40, and more optionally 0.04-5.

20. The battery according to any one of claims 14 to 19, wherein The positive electrode film layer also includes a positive electrode active material, and the ratio of the Dv50 particle size of the positive electrode lithium supplement to the Dv50 particle size of the positive electrode active material is 0.05-15, optionally 1-10, and more optionally 2-8.

21. The battery according to any one of claims 14 to 20, wherein The active specific surface area of ​​the positive electrode sheet is greater than 0 cm 2 / g and less than or equal to 25cm 2 / g, can be selected to be greater than 0cm 2 / g and less than or equal to 20cm 2 / g, more preferably greater than or equal to 0.5cm 2 / g and less than or equal to 20cm 2 / g, further optionally greater than or equal to 2cm 2 / g and less than or equal to 10cm 2 / g.

22. An electrical device comprising the battery according to any one of claims 13 to 21.

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