battery

Abstract

The present invention relates to the technical field of batteries, and in particular to a battery. The battery comprises an electrolyte and a positive electrode sheet, the electrolyte comprises an ether nitrile compound, and the ether nitrile compound comprises a compound having the structure of NC-M1-O-M2; M2 is selected from -CN or a group comprising -O-N1-CN, and M1 and N1 are each independently selected from C1-C9 alkyl, C2-C9 alkenyl, C2-C9 alkynyl, and C2-C9 ether; based on the total weight of the electrolyte, the weight content of the ether nitrile compound is Awt%; the positive electrode sheet comprises a lithium cobalt oxide material and a carbon nanotube; and the median particle size Dv50 of the lithium cobalt oxide material is C, the unit of the median particle size Dv50 is μm, the diameter of the carbon nanotube is L, the unit of the diameter is nm, and the battery meets the condition: 0.25≤(A / (C+L))×100≤25. The battery has high cycle stability and good high-temperature storage performance.

Description

A battery Technical Field

[0001] The present disclosure relates to the technical field of batteries, and in particular to a battery. Background Art

[0002] Lithium-ion batteries are widely used in smart electronic devices, power systems, and large-scale energy storage systems due to their comprehensive advantages such as high energy density, good safety, and long cycle life. Currently, with consumers' increasing requirements for the "endurance" of electronic devices, how to further improve the energy density of lithium-ion batteries has become very critical. In order to effectively improve the energy density of batteries, the most important strategy is to increase the operating voltage of the battery. However, lithium-ion batteries will face problems such as electrolyte decomposition, positive electrode material phase change, and electrode-electrolyte interface side reactions at high voltages (above 4.45V), which will accelerate the battery capacity decay, resulting in poor cycle stability, gas production, and poor storage performance. Summary of the Invention

[0003] To address the technical challenges faced by batteries at high voltages, such as electrolyte decomposition, cathode material phase transitions, and electrode-electrolyte interface side reactions, which can lead to poor cycling stability, gas generation, and poor storage performance, the present disclosure provides a battery with high cycling stability and excellent high-temperature storage performance.

[0004] Research has found that by improving the stability of the electrolyte and the positive electrode, side reactions at the electrode-electrolyte interface can be reduced, thereby improving the battery's cycle stability and high-temperature storage performance.

[0005] Further in-depth research found that in order to improve the stability of the electrolyte and the positive electrode, compounds with specific structures can be added to the electrolyte and cooperated with the positive electrode to improve the stability of the electrolyte and the positive electrode.

[0006] To achieve the above objectives, the present disclosure provides a battery, comprising an electrolyte and a positive electrode sheet, the electrolyte comprising an ether nitrile compound, the ether nitrile compound comprising a compound having a structure of NC-M1-O-M2; wherein M2 is selected from -CN or a group comprising -O-N1-CN, M1 and N1 are each independently selected from a substituted or unsubstituted C1-C9 alkyl group, a substituted or unsubstituted C2-C9 alkenyl group, a substituted or unsubstituted C2-C9 alkynyl group, or a substituted or unsubstituted C2-C9 ether group; the substituted substituent is selected from one or more halogens; the weight content of the ether nitrile compound is Awt% based on the total weight of the electrolyte; the positive electrode sheet comprises a lithium cobalt oxide material and carbon nanotubes, the median particle size Dv50 of the lithium cobalt oxide material is C, in μm, and the diameter of the carbon nanotubes is L, in nm, and the battery satisfies the following conditions: 1.1≤(A / (C+L))×100≤20.

[0007] Through the above technical solution, the present disclosure has at least the following advantages compared with the prior art:

[0008] By adding ether nitrile compounds to the electrolyte and using specific lithium cobalt oxide materials and carbon nanotube materials, the stability of the electrolyte and the positive electrode can be improved by regulating the relationship between the ether nitrile compounds, lithium cobalt oxide materials and carbon nanotube materials, thereby improving the cycle stability of the battery at high voltage and the high-temperature storage performance.

[0009] Other features and advantages of the present disclosure will be described in detail in the following detailed description.

[0010] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein. DETAILED DESCRIPTION

[0011] The specific embodiments of the present disclosure are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure and are not intended to limit the present disclosure. In this article, unless otherwise specified, data ranges include endpoints.

[0012] The present disclosure provides a battery, comprising an electrolyte and a positive electrode sheet, the electrolyte comprising an ether nitrile compound, the ether nitrile compound comprising a compound having a structure of NC-M1-O-M2; wherein M2 is selected from -CN or a group comprising -O-N1-CN, M1 and N1 are each independently selected from a substituted or unsubstituted C1-C9 alkyl group, a substituted or unsubstituted C2-C9 alkenyl group, a substituted or unsubstituted C2-C9 alkynyl group, or a substituted or unsubstituted C2-C9 ether group; the substituted substituent is selected from one or more halogens; the weight content of the ether nitrile compound is Awt% based on the total weight of the electrolyte; the positive electrode sheet comprises a lithium cobalt oxide material and carbon nanotubes, the median particle size Dv50 of the lithium cobalt oxide material is C, in μm, and the diameter of the carbon nanotubes is L, in nm, and the battery satisfies the following conditions: 0.25≤(A / (C+L))×100≤25.

[0013] Adding an ether nitrile compound to the electrolyte can make the ether nitrile compound adhere to the positive electrode sheet including the lithium cobalt oxide material with a specific median particle size. The cyanide group in the ether nitrile compound interacts with metal ions such as cobalt ions in the positive electrode sheet, thereby reducing the dissolution of ions in the positive electrode sheet, thereby improving the stability of the positive electrode sheet. By mixing carbon nanotubes of a specific diameter with high chemical inertness and strong electron donating ability into the lithium cobalt oxide material with a specific Dv50, the dispersion of the lithium cobalt oxide material in the carbon nanotubes is promoted, and a good three-dimensional conductive path can be constructed between the lithium cobalt oxide materials. Through the adsorption of cyanide groups by carbon nanotubes, the adsorption effect of cyanide functional groups on the surface of the positive electrode sheet can be enhanced, so that the ether nitrile compound can be further attached to the surface of the positive electrode sheet, thereby improving the protection of the positive electrode sheet.

[0014] The battery is controlled to satisfy the following conditions: 0.25≤(A / (C+L))×100≤25 (for example, 0.25, 0.5, 1, 1.1, 1.5, 2, 5, 7, 10, 12, 15, 17, 20, 22, 25). This allows the ether nitrile compound to form a strong adsorption effect with the lithium cobalt oxide and the carbon nanotubes, thereby forming an efficient interaction relationship between the ether nitrile compound and the positive electrode sheet. The cyano group in the ether nitrile compound can directionally complex the active ions of the lithium cobalt oxide material (such as cobalt or other doped metal elements), thereby improving the structural stability of the lithium cobalt oxide material. At the same time, the introduction of carbon nanotubes with high chemical inertness and strong electron donating ability into the positive electrode sheet can enhance the adsorption of the carbon nanotubes on the cyano functional groups in the ether nitrile compound without causing other adverse reactions, thereby improving the stability of the electrolyte and the positive electrode sheet, thereby improving the cycle stability and high-temperature storage performance of the battery. When (A / (C+L))×100 is less than 0.25, the interaction between the ether nitrile compound and the carbon nanotubes is weak, and they cannot effectively complex the active ions in the lithium cobalt oxide material, resulting in the destruction of the lithium cobalt oxide material structure, degradation of the battery's cycle performance, gassing, reduced high-temperature storage performance, and decreased resistance to electrical abuse. When (A / (C+L))×100 is higher than 25, excessive ether nitrile compounds accumulate at the interface between the electrolyte and the positive electrode, deteriorating the battery's kinetic performance, resulting in low battery energy density and prolonged charging time.

[0015] By adding the above-mentioned ether nitrile compound with a specific structure to the electrolyte, and by synergizing the ether nitrile compound with a lithium cobalt oxide material of a specific median particle size and carbon nanotubes of a specific tube diameter, the battery has been able to achieve higher cycle stability and higher high-temperature storage performance than existing technologies.

[0016] When based on the total weight of the electrolyte, the weight content Awt% of the ether nitrile compound is 1.2wt%, the median particle size C of the lithium cobalt oxide material is 8μm, and the diameter L of the carbon nanotube is 2nm, (A / (C+L))×100=(1.2 / (8+2))×100=12.

[0017] In one example, the battery satisfies: 1.1≤(A / (C+L))×100≤20.

[0018] In one embodiment, the ether nitrile compound is C n -P m and / or having the structure represented by formula (I), Among them C nis a main chain with a straight chain structure, n is a positive integer of 1-4, P is a graft chain connected to the main chain C, m is a positive integer of 3-8, and the graft chains P in the ether polynitrile compound are each independently selected from -R2-O-R1-CN, wherein T1, T2, R1, and R2 are each independently selected from substituted or unsubstituted C1-C9 alkyl, substituted or unsubstituted C2-C9 alkenyl, substituted or unsubstituted C2-C9 alkynyl, substituted or unsubstituted C2-C9 ether group, and empty bond, and R1 and R2 are not empty bonds at the same time, and the substituted substituents are selected from one or more halogens.

[0019] C n It can be a main chain with a straight chain structure, n is a positive integer of 1-4, for example, 1, 2, 3, 4, then C n It can be -C-, -CC-, -CCC- or -CCCC.

[0020] P is a graft chain connected to the main chain C, that is, P can be connected to the C atom of the above C chain.

[0021] m can be a positive integer from 3 to 8, for example, 3, 4, 5, 6, 7, or 8.

[0022] In one embodiment, m>n. When m>n, the chain length of the ether nitrile compound is moderate, which facilitates the rotation of the molecule and its attachment to the positive electrode surface, and does not increase the viscosity of the electrolyte due to excessive chain length, thereby affecting the wettability.

[0023] The graft chains P in the ether polynitrile compound may be the same or different and are each independently selected from -R2-O-R1-CN.

[0024] T1, T2, R1, and R2 may be the same or different and are independently selected from substituted or unsubstituted C1-C9 alkyl, substituted or unsubstituted C2-C9 alkenyl, substituted or unsubstituted C2-C9 alkynyl, substituted or unsubstituted C2-C9 ether, and empty bonds, and R1 and R2 are not empty bonds at the same time.

[0025] In this disclosure, an empty bond means that there is no group or atomic group at that position. For example, if R1 is an empty bond, the O on one side is directly connected to the cyano group on the other side; if R2 is an empty bond, the O on one side is directly connected to the C on the main chain.

[0026] R1 and R2 are not empty keys at the same time, which means that the number of empty keys in R1 and R2 is less than 2, that is, when R1 is an empty key, R2 is not an empty key; when R2 is an empty key, R1 is not an empty key; R1 and R2 can be non-empty keys at the same time.

[0027] In one embodiment, the ether nitrile compound includes one or more structures represented by formula (I), formula (II), formula (III), formula (IV), formula (V) and formula (VI), Among them, T1, T2, R3, R4, R5, R6, R7, R8, R9, R 10 、R 11 、R 12 、R 13 、R 14 、R 15 、R 16 、R 17 、R 18 、R 19 、R 20 、R 21 、R 22 、R 23 、R 24 、R 25 、R 26 、R 27 、R 28 、R 29 、R 30 、R 31 、R 32 、R 33 、R 34 、R 35 、R 36 Each is independently selected from a substituted or unsubstituted C1-C9 alkyl, a substituted or unsubstituted C2-C9 alkenyl, a substituted or unsubstituted C2-C9 alkynyl, a substituted or unsubstituted C2-C9 ether group, and the substituted substituent is selected from one or more of halogen.

[0028] T1, T2, R3, R4, R5, R6, R7, R8, R9, R 10 、R 11 、R 12 、R 13 、R 14 、R 15 、R 16 、R 17 、R 18 、R 19 、R 20 、R 21 、R 22 、R 23 、R 24 、R 25 、R 26 、R 27 、R 28 、R 29 、R 30 、R 31 、R32 、R 33 、R 34 、R 35 、R 36 They may be the same or different, and are each independently selected from a substituted or unsubstituted C1-C9 alkyl group, a substituted or unsubstituted C2-C9 alkenyl group, a substituted or unsubstituted C2-C9 alkynyl group, or a substituted or unsubstituted C2-C9 ether group.

[0029] In the present disclosure, the expression "substituted or unsubstituted" means, for example, "substituted or unsubstituted C1-C9 alkyl", which means that the alkyl group may be substituted or may not be substituted by any substituent. When the alkyl group is substituted by a substituent, one H in the alkyl group may be substituted, multiple H groups may be substituted, or all H groups may be substituted.

[0030] The structural formulas of the ether nitrile compounds are shown in formula (I), formula (II), formula (III), formula (IV), formula (V) and formula (VI). It can be seen that T1, T2, R3, R4, R7, R8, R 10 、R 11 、R 13 、R 14 、R 16 、R 17 、R 18 、R 20 、R 21 、R 24 、R 26 、R 28 、R 29 、R 31 、R 32 、R 33 、R 34 、R 36 Both sides of the are connected to O atoms and cyano groups, R5, R6, R9, R 12 、R 15 、R 19 、R 22 、R 23 、R 25 、R 27 、R 30 、R 35 Both sides of the are connected to C atoms and cyano groups, so R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 、R 11 、R 12 、R 13 、R 14 、R 15 、R 16 、R 17 、R 18 、R19 、R 20 、R 21 、R 22 、R 23 、R 24 、R 25 、R 26 、R 27 、R 28 、R 29 、R 30 、R 31 、R 32 、R 33 、R 34 、R 35 、R 36 The selected alkyl, alkenyl, alkynyl, and ether groups can all satisfy the structures of formula (I), formula (II), formula (III), formula (IV), formula (V) and formula (VI). For example, if R1 is a methyl group, the structure of the methyl group is -CH2-.

[0031] The C1-C9 alkyl group is, for example, selected from methyl, ethyl, n-propyl, isopropyl, cyclopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, cyclobutyl, n-pentyl, isopentyl, tert-pentyl, neopentyl, cyclopentyl, 2,2-dimethylpropyl, 1-ethylpropyl, 1-methylbutyl, 2-methylbutyl, n-hexyl, isohexyl, 2-hexyl, 3-hexyl, cyclohexyl, 2-methylpentyl, 3-methylpentyl, 1,1,2-trimethylpropyl, 3,3-dimethylbutyl, n-heptyl, 2-heptyl, 3-heptyl, 2-methylhexyl, 3-methylhexyl, 4-methylhexyl, isoheptyl, cycloheptyl, n-octyl, cyclooctyl, and nonyl.

[0032] The C2-C9 alkenyl group is, for example, selected from vinyl, n-propenyl, isopropenyl, cyclopropenyl, n-butenyl, isobutenyl, sec-butenyl, tert-butenyl, cyclobutenyl, n-pentenyl, isopentenyl, tert-pentenyl, neopentenyl, cyclopentenyl, 2,2-dimethylpropenyl, 1-ethylpropenyl, 1-methylbutenyl, 2-methylbutenyl, n-hexenyl, isohexenyl, 2-hexenyl, 3-hexenyl, cyclohexenyl, 2-methylpentenyl, 3-methylpentenyl, 1,1,2-trimethylpropenyl, 3,3-dimethylbutenyl, n-heptenyl, 2-heptenyl, 3-heptenyl, 2-methylhexenyl, 3-methylhexenyl, 4-methylhexenyl, isoheptenyl, cycloheptenyl, n-octenyl, cyclooctenyl, and nonyl.

[0033] The C2-C9 alkynyl group is, for example, selected from ethynyl, n-propynyl, isopropynyl, n-butynyl, isobutynyl, sec-butynyl, tert-butynyl, n-pentynyl, isopentenyl, tert-pentynyl, neopentynyl, 2,2-dimethylpropynyl, 1-ethylpropynyl, 1-methylbutynyl, 2-methylbutynyl, n-hexynyl, isohexynyl, 2-hexynyl, 3-hexynyl, cyclohexynyl, 2-methylpentynyl, 3-methylpentynyl, 1,1,2-trimethylpropynyl, 3,3-dimethylbutynyl, n-heptynyl, 2-heptynyl, 3-heptynyl, 2-methylhexynyl, 3-methylhexynyl, 4-methylhexynyl, isoheptynyl, cycloheptynyl, n-octynyl, cyclooctynyl, and nonynyl.

[0034] The C2-C9 ether group is, for example, selected from ethyl ether, n-propyl ether, butyl ether, methyl ethyl ether, methyl propyl ether, isopropyl ether, ethyl propyl ether, and butyl amyl ether.

[0035] T1, T2, R3, R4, R5, R6, R7, R8, R9, R 10 、R 11 、R 12 、R 13 、R 14 、R 15 、R 16 、R 17 、R 18 、R 19 、R 20 、R 21 、R 22 、R 23 、R 24 、R 25 、R 26 、R 27 、R 28 、R 29 、R 30 、R 31 、R 32 、R 33 、R 34 、R 35 、R 36 may be the same or different, and are each independently selected from a substituted or unsubstituted C1-C5 alkyl group, a substituted or unsubstituted C2-C5 alkenyl group, a substituted or unsubstituted C2-C5 alkynyl group, or a substituted or unsubstituted C2-C5 ether group;

[0036] In one embodiment, the substituted substituent is selected from one or more halogens, which may be F, Cl, Br, or I.

[0037] In one embodiment, the substituted substituent is selected from F. When the substituted substituent is F, F can improve the oxidation resistance of the ether nitrile compound and prevent the functional group (cyano group) from decomposing to form an excessive interface film.

[0038] In one embodiment, the ether nitrile compound at least comprises a structure represented by formula (VI).

[0039] In one embodiment, the ether nitrile compound at least includes the structures represented by formula (V) and formula (VI).

[0040] In one embodiment, the ether nitrile compound at least includes the structures represented by formula (IV), formula (V) and formula (VI).

[0041] In one embodiment, the ether nitrile compound includes at least the structures represented by formula (II), formula (IV), formula (V) and formula (VI).

[0042] In one embodiment, the ether nitrile compound includes at least the structures represented by formula (II), formula (III), formula (IV), formula (V) and formula (VI).

[0043] In one embodiment, the ether nitrile compound has the structure represented by formula (I), formula (II), formula (III), formula (IV), formula (V) and formula (VI).

[0044] In one example, the ether nitrile compound includes one or more of the following structures:

[0045] The ether nitrile compound can be purchased commercially or prepared through conventional preparation processes.

[0046] According to a specific embodiment, based on the total weight of the electrolyte, the weight content Awt% of the ether nitrile compound is 0.1wt%-6wt% (for example, 0.1wt%, 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, 5wt%, 5.5wt%, 6wt%). When the weight content of the ether nitrile compound in the electrolyte is lower than 0.1wt%, the content of the ether nitrile compound is too little to protect the positive electrode interface, resulting in a decrease in battery performance and gas production in the battery cell; when the weight content of the ether nitrile compound in the electrolyte is higher than 6wt%, the content of the ether nitrile compound is too much, which will increase the viscosity of the electrolyte and deteriorate the rate performance of the battery. When the weight content of the ether nitrile compound in the electrolyte is within the above range, it is not only sufficient to protect the positive electrode interface, but also can make the viscosity of the electrolyte more moderate, thereby making the overall performance of the battery better.

[0047] In one embodiment, based on the total weight of the electrolyte, the weight content Awt% of the ether nitrile compound is 0.2wt%-3.5wt%. When the weight content of the ether nitrile compound in the electrolyte is limited to the above specific range, the overall performance of the battery can be further optimized.

[0048] In one example, the electrolyte includes a lithium salt, an organic solvent, and a functional additive.

[0049] In one example, the lithium salt includes one or more of lithium hexafluorophosphate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethylsulfonyl imide, lithium difluorobisoxalatophosphate, and lithium tetrafluoroborate.

[0050] In one embodiment, the weight content of the lithium salt is 10 wt% to 18 wt% (e.g., 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%) based on the total weight of the electrolyte. When the weight content of the lithium salt in the electrolyte is higher than 18 wt%, stress and damage inside the battery may be increased, resulting in a shortened cycle life of the battery. When the weight content of the lithium salt in the electrolyte is lower than 10 wt%, the discharge capacity of the battery may be affected.

[0051] In one example, based on the total weight of the electrolyte, the weight content of the lithium salt is 14 wt%-16 wt%.

[0052] In one example, the organic solvent includes an acid ester and / or a carboxylic acid ester; the carboxylic acid ester includes one or more of the following fluorinated or unsubstituted solvents: propyl acetate, n-butyl acetate, isobutyl acetate, n-amyl acetate, isoamyl acetate, propyl propionate, ethyl propionate, methyl butyrate, ethyl n-butyrate; the carbonate includes one or more of the following fluorinated or unsubstituted solvents: ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate.

[0053] In one example, based on the total weight of the electrolyte, the weight content of the organic solvent is 54 wt%-79 wt% (eg, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, 79 wt%).

[0054] In one embodiment, based on the total weight of the electrolyte, the weight content of the organic solvent is 60 wt % to 70 wt %.

[0055] In one embodiment, the electrolyte includes a functional additive. When the electrolyte includes the ether nitrile compound and the functional additive, the ether nitrile compound, lithium cobalt oxide material, and carbon nanotubes in the electrolyte not only improve the stability of the electrolyte and the positive electrode sheet, but the functional additive also promotes the formation of a stable and effective interface film on the electrode surface, increasing the ion transfer rate, thereby further improving the battery cycle and storage stability.

[0056] In one example, the functional additive includes one or more of a cyclic carbonate additive, a cyclic sultone additive, and a lithium salt additive.

[0057] In one embodiment, the cyclic carbonate additive includes one or more of fluoroethylene carbonate, vinylene carbonate, and vinyl ethylene carbonate. The cyclic carbonate additive can promote the formation of an effective solid electrolyte interface on the negative electrode surface, protect the negative electrode interface, and improve battery stability.

[0058] In one embodiment, the cyclic sultone additive includes one or more of 1,3-propane sultone, 1,3-propylene sultone, 2,4-butane sultone, and 1,4-butane sultone. The cyclic sultone additive can form an effective interfacial film on the positive electrode surface, facilitating the fixation of the ether nitrile compound on the film structure to complex metal ions and thereby improving the utilization rate of the ether nitrile compound.

[0059] In one embodiment, the lithium salt additive is selected from one or more of lithium difluorooxalatoborate, lithium difluorophosphate, and lithium difluorobisoxalatophosphate combined with lithium dioxalatoborate. The lithium salt additive is beneficial for adjusting the interfacial film composition of the negative electrode or positive electrode, forming a low-impedance interface containing boron or phosphorus, thereby reducing battery resistance.

[0060] In one example, based on the total weight of the electrolyte, the weight content of the functional additive is 10 wt%-30 wt% (eg, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%).

[0061] In one example, based on the total weight of the electrolyte, the weight content of the functional additive is 15 wt%-25 wt%.

[0062] In one example, the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer located on one side or both sides of the positive electrode current collector, wherein the positive electrode active material layer includes a lithium cobalt oxide material and a conductive material.

[0063] In one example, the lithium cobalt oxide material is lithium cobalt oxide that has been doped or coated.

[0064] In one embodiment, the chemical formula of the lithium cobalt oxide material is Li x Co z A y1 B y2 C y3 D y4 O2. Chemical formula Li x Co1-y1-y2-y3- y4 A y1 B y2 C y3 D y4 O2 satisfies the principle that the algebraic sum of the positive and negative valences of each element is zero.

[0065] Among them, 0.95≤x≤1.05 (for example, 0.95, 0.96, 0.97, 0.98, 0.98, 1, 1.01, 1.02, 1.03, 1.04, 1.05), 0≤y1≤0.1 (for example, 0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1), 0≤y2≤0.1 (for example, 0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06 , 0.07, 0.08, 0.09, 0.1), 0≤y3≤0.1 (for example, 0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1), 0≤y4≤0.1 (for example, 0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1), 0.6≤z≤1 (for example, 0.6, 0.7, 0.8, 0.9, 1). When y1, y2, y3 and y4 are all 0, the lithium cobalt oxide material is lithium cobalt oxide that has not been doped or coated. When y1, y2, y3 and y4 are not all 0, the lithium cobalt oxide material is lithium cobalt oxide that has been doped and coated.

[0066] In one example, A, B, C, and D are doping elements, and A, B, C, and D include one or more of Al, Mg, Mn, Cr, Ti, Zr, Y, La, B, and Ce.

[0067] In one embodiment, A, B, C, and D include one or more of Al, Mg, and Ti. When A, B, C, and D include these specific elements as doping elements, they can improve defects within the lithium cobalt oxide material particles and suppress structural phase transitions caused by electrochemical performance degradation during high-voltage charge and discharge.

[0068] In one example, based on the total weight of the lithium cobalt oxide material, the weight content of the doping element is 0.02wt%-0.1wt% (for example, 0.02wt%, 0.03wt%, 0.04wt%, 0.05wt%, 0.06wt%, 0.07wt%, 0.08wt%, 0.09wt%, 0.1wt%).

[0069] In one embodiment, based on the total weight of the lithium cobalt oxide material, the weight content of the doping element is 0.04 wt %-0.08 wt %.

[0070] In one embodiment, A, B, C, and D include one or more of Al, Mg, and Ti, and the weight content of the doping element is 0.04 wt% to 0.08 wt% based on the total weight of the lithium cobalt oxide material. When A, B, C, and D are selected from the above-mentioned specific elements as doping elements, and the weight content of the doping element in the lithium cobalt oxide material is within the above-mentioned range, the complexation of the lithium cobalt oxide material with the cyano group in the ether nitrile compound during high-voltage charge and discharge can be enhanced, thereby improving the cycle stability of the lithium cobalt oxide material.

[0071] In one embodiment, the surface of the lithium cobalt oxide has a coating layer.

[0072] In one embodiment, the coating layer has a thickness less than 50 nm (eg, 1 nm, 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 45 nm, 49 nm). When the coating layer has a thickness greater than or equal to 50 nm, it will hinder the conduction of lithium ions and increase the impedance of the battery.

[0073] In one example, the coating layer is selected from one or more of carbon materials, Al2O3, TiO2, ZrO2, MgO, CoO2, CoO, NiO, MnO2, Mn3O4, NbO3, Ta2O5, AlF3, MgF2, CuF2, AlPO3, Li3PO3, lithium lanthanum zirconium oxide (LLZO), lithium aluminum titanium phosphate (LATP), LiCoPO4, Zr3(PO4)4 and Li2PO3F.

[0074] In one embodiment, based on the total weight of the lithium cobalt oxide material, the weight content of the coating layer is 0 wt%-5 wt% (e.g., 0 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, 5 wt%). When the weight content of the coating layer is 0 wt%, it means that the lithium cobalt oxide material does not have a coating layer.

[0075] In one example, based on the total weight of the lithium cobalt oxide material, the weight content of the coating layer is 0.05 wt%-0.12 wt%.

[0076] In one example, based on the total weight of the lithium cobalt oxide material, the weight content of the coating layer is 0.05wt%-0.12wt%, and / or the doping element is Al element, and based on the total weight of the lithium cobalt oxide material, the weight content of Al element is 0.04wt%-0.08wt% (for example, 0.04wt%, 0.05wt%, 0.06wt%, 0.07wt%, 0.08wt%).

[0077] In one embodiment, the lithium cobalt oxide material is a doped and coated modified lithium cobalt oxide material, the doped and coated modified lithium cobalt oxide material has a core-shell structure, the core is the doped and coated modified lithium cobalt oxide material, wherein the chemical formula is Li x Co 1-y1 Al y1 O2, in the doped and modified lithium cobalt oxide material, the weight content of the doping element Al is 0.04wt%-0.08wt%, the shell is a coating layer formed of a carbon material, and the thickness of the coating layer is 20nm-50nm. In the doped and coated modified lithium cobalt oxide material, the weight content of the carbon material is 0.05wt%-0.12wt%. The doped and coated lithium cobalt oxide material with the above-mentioned specific structure can enhance the complexation between the cobalt and Al elements in the lithium cobalt oxide material and the cyano group in the ether nitrile compound, thereby improving the structural stability of the lithium cobalt oxide material and enhancing the cycle stability and high-temperature storage performance of the battery.

[0078] According to a specific embodiment, the median particle size Dv50 of the lithium cobalt oxide material is 8 μm-25 μm (e.g., 8 μm, 10 μm, 12 μm, 15 μm, 18 μm, 20 μm, 22 μm, 25 μm). In the present disclosure, the median particle size Dv50 can be measured by a particle size analyzer.

[0079] In one example, the median particle size Dv50 of the lithium cobalt oxide material is 13 μm-18 μm.

[0080] According to a specific embodiment, the diameter L of the carbon nanotubes is 0.5 nm-15 nm (for example, 0.5 nm, 1 nm, 1.5 nm, 2 nm, 3 nm, 5 nm, 7 nm, 10 nm, 12 nm, 15 nm).

[0081] In one example, the carbon nanotubes are single-walled carbon nanotubes.

[0082] In one example, the diameter of the single-walled carbon nanotube is 0.5 nm-2 nm.

[0083] In one embodiment, the aspect ratio of the single-walled carbon nanotubes is 500 to 2000. When the aspect ratio of the single-walled carbon nanotubes is within the above specific range, they can withstand large tensile and compressive forces, which is beneficial to increasing the strength of the electrode and the stability of the battery.

[0084] In one embodiment, the carbon nanotubes are single-walled carbon nanotubes, and the diameter of the single-walled carbon nanotubes is 1nm-2nm, and the aspect ratio of the single-walled carbon nanotubes is 500-2000. When the diameter and aspect ratio of the single-walled carbon nanotubes are limited to the above-mentioned specific ranges, the single-walled carbon nanotubes have a small diameter and a larger aspect ratio, and have better conductivity and greater flexibility, and can be better bent, twisted, or kinked. Their elastic modulus and tensile strength are significantly better than those of multi-walled carbon nanotubes. Therefore, the single-walled carbon nanotubes are easier to evenly disperse in the coating, while also facilitating uniform electron transmission. In addition, the single-walled carbon nanotubes can combine with more lithium cobalt oxide materials, facilitating the uniform adsorption of the ether nitrile compound on the positive electrode sheet, thereby significantly improving the battery's cyclability and capacity.

[0085] In one embodiment, the conductive material includes carbon nanotubes and a first conductive agent, and the weight ratio of the carbon nanotubes to the first conductive agent is (0.2-3):1 (e.g., 0.2:1, 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1). When the weight ratio of the carbon nanotubes to the first conductive agent is limited to the above-mentioned specific range, the first conductive agent can enhance the wetting effect of the electrolyte on the electrode, overcoming the problems of increased viscosity and poor wetting caused by the introduction of the ether nitrile compound.

[0086] In one example, the ratio of the weight of the carbon nanotubes to the weight of the first conductive agent is (0.5-2):1.

[0087] In one example, the first conductive agent includes one or more of conductive carbon black, acetylene black, Ketjen black, conductive graphite, and conductive carbon fiber.

[0088] According to a specific embodiment, based on the total weight of the positive electrode active material layer, the weight content of the lithium cobalt oxide material is 80 wt%-99.8 wt%, and the weight content of the conductive material is 0.1 wt%-10 wt%.

[0089] According to a specific embodiment, based on the total weight of the positive electrode active material layer, the weight content of the lithium cobalt oxide material is 90 wt %-99.6 wt %, and the weight content of the conductive material is 0.2 wt %-5 wt %.

[0090] In one example, the battery includes a negative electrode sheet.

[0091] In one example, the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer coated on one or both sides of the negative electrode current collector, wherein the negative electrode active material layer includes a negative electrode active material, a second conductive agent, and a second binder.

[0092] In one embodiment, the negative electrode active material includes graphite and optionally contains hard carbon, soft carbon, SiO x (0<x<2), Si graphite mixed material.

[0093] In one example, the second conductive agent includes one or more of conductive carbon black, acetylene black, Ketjen black, conductive graphite, conductive carbon fiber, and carbon nanotubes.

[0094] In one example, the second binder includes one or more of sodium carboxymethyl cellulose, styrene-butadiene latex, polytetrafluoroethylene, polyethylene oxide, and polyvinylidene fluoride.

[0095] In one example, based on the total weight of the negative electrode active material layer, the weight content of the negative electrode active material is 80wt%-99.8wt%, the weight content of the second conductive agent is 0.1wt%-10wt%, and the weight content of the second binder is 0.1wt%-10wt%.

[0096] In one example, based on the total weight of the negative electrode active material layer, the weight content of the negative electrode active material is 90wt%-99wt%, the weight content of the second conductive agent is 0.2wt%-5wt%, and the weight content of the second binder is 0.2wt%-5wt%.

[0097] The battery may be a lithium-ion battery.

[0098] The battery may be a lithium-ion secondary battery.

[0099] The present disclosure will be described in detail below through examples. The examples described in this disclosure are only a portion of the examples of the present disclosure, not all of the examples. Based on the examples in this disclosure, all other examples obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this disclosure.

[0100] The following examples are used to illustrate the electrolyte and positive electrode sheet of the present disclosure.

[0101] Example 1

[0102] (1) Preparation of ingredients

[0103] Electrolyte: 3 parts by weight of an ether nitrile compound (having the structure shown in Formula IV-2), 14 parts by weight of a lithium salt (LiPF6), 67 parts by weight of an organic solvent (including 8 parts by weight of ethylene carbonate (EC), 8 parts by weight of propylene carbonate (PC), 15 parts by weight of ethyl propionate (EP), and 36 parts by weight of propyl propionate (PP)), and 16 parts by weight of a functional additive (including 11.5 parts by weight of FEC, 4 parts by weight of 1,3-propane sultone, and 0.5 parts by weight of lithium difluorooxalatoborate).

[0104] Positive electrode sheet: positive electrode current collector (aluminum foil with a thickness of 10 μm), lithium cobalt oxide material (median particle size Dv is 15 μm) 97 parts by weight, conductive material (carbon nanotubes (single-walled carbon nanotubes, tube diameter L is 1.5 nm) 0.5 parts by weight, first conductive agent (conductive carbon black (Super P)) 0.5 parts by weight) 1 part by weight, first binder (polyvinylidene fluoride (PVDF 500)) 2 parts by weight.

[0105] (2) Preparation of electrolyte

[0106] In a glove box filled with argon (moisture <5ppm, oxygen <1ppm), the organic solvents are mixed evenly, lithium salt is slowly added to the mixed solution, and then the ether nitrile compound and functional additives are added and stirred evenly. After passing the moisture and free acid tests, the required electrolyte is obtained.

[0107] (3) Preparation of positive electrode

[0108] The lithium cobalt oxide material, the first binder, and the first conductive agent are mixed and added to an N-methylpyrrolidone (NMP) solvent. A uniform and fluid positive electrode slurry is then stirred in a blender. The positive electrode slurry is then evenly coated on one side of the positive electrode current collector and dried in a vacuum oven at 120°C for 8 hours. The desired positive electrode sheets are then produced by rolling and slitting.

[0109] Example 2 group

[0110] This group of examples is used to illustrate the effects of changing the content Awt% of the ether nitrile compound in the electrolyte.

[0111] This group of examples was carried out with reference to Example 1, except that the content Awt% of the ether nitrile compound in the electrolyte was changed. For details, see Tables 1-1 and 1-2.

[0112] Example 3 group

[0113] This set of examples is used to illustrate the effects of varying the specific selection of the ether nitrile compound.

[0114] This group of examples was carried out with reference to Example 1, except that the specific selection of the ether nitrile compound was changed. For details, see Tables 1-1 and 1-2.

[0115] Example 4 Group

[0116] This group of examples is used to illustrate the effects of changes in the median particle size of the lithium cobalt oxide material.

[0117] This group of examples was carried out with reference to Example 1, except that the median particle size of the lithium cobalt oxide material was changed. For details, see Tables 1-1 and 1-2.

[0118] Example 5 group

[0119] This group of examples is used to illustrate the impact produced when the specific selection of lithium cobalt oxide material is changed.

[0120] This group of examples is carried out with reference to Example 1, except that the specific selection of lithium cobalt oxide material is changed. For details, see Tables 1-1 and 1-2.

[0121] Example 6

[0122] This set of examples is used to illustrate the effects of changing the diameter L of carbon nanotubes.

[0123] This group of examples was carried out with reference to Example 1, except that the diameter L of the carbon nanotubes was changed. For details, see Tables 1-1 and 1-2.

[0124] Example 7 Group

[0125] This set of examples is used to illustrate the effects of changing the weight content of the functional additives in the electrolyte.

[0126] This group of examples was carried out with reference to Example 1, except that the weight content of the functional additives in the electrolyte was changed. For details, see Tables 1-1 and 1-2.

[0127] Example 8 Group

[0128] This group of examples is used to illustrate the effects of changing the weight ratio of the carbon nanotubes to the first conductive agent.

[0129] This group of examples was carried out with reference to Example 1, except that the weight ratio of the carbon nanotubes to the first conductive agent was changed. For details, see Tables 1-1 and 1-2.

[0130] Comparative Example 1

[0131] The same procedure was followed as in Example 1, except that no ether nitrile compound was added to the electrolyte. For details, see Tables 1-1 and 1-2.

[0132] Comparative Example 2

[0133] The same procedure was carried out as in Example 1, except that the weight content of the ether nitrile compound in the electrolyte was changed so that (A / (C+L))×100 was 0.5. For details, see Tables 1-1 and 1-2.

[0134] Comparative Example 3

[0135] The same procedure was followed as in Example 1, except that the median particle size of the lithium cobalt oxide material was changed so that (A / (C+L))×100 was 22. For details, see Tables 1-1 and 1-2.

[0136] Table 1-1

[0137] Table 1-2

[0138] * indicates the same as Example 1;

[0139] - means it does not exist.

[0140] Preparation Example

[0141] Batteries were prepared using the electrolytes and positive electrodes obtained in the examples and comparative examples in the following manners.

[0142] (1) Positive electrode

[0143] The positive electrode sheets obtained in the above embodiments and comparative examples were used respectively.

[0144] (2) Negative electrode

[0145] 97% natural graphite anode material, 0.5% single-walled carbon nanotube (SWCNT) conductive agent, 0.5% conductive carbon black (Super P) conductive agent, 0.5% sodium carboxymethyl cellulose (CMC) binder, and 1.5% styrene-butadiene rubber (SBR) binder are mixed in an aqueous phase and stirred in a blender to form a uniform and fluid anode slurry. Subsequently, the slurry is coated on the surface of the anode current collector copper foil, dried in a vacuum oven at 120°C for 8 hours, and then rolled and slit to obtain the desired anode sheets.

[0146] (3) Electrolyte

[0147] The electrolytes obtained in the above-mentioned embodiments and comparative examples were used respectively.

[0148] (4) Diaphragm

[0149] A composite layer of titanium oxide and polyvinylidene fluoride-hexafluoropropylene copolymer with a thickness of 2 μm is coated on a polyethylene separator with a thickness of 5 μm.

[0150] (5) Preparation of lithium-ion batteries

[0151] The positive electrode sheet of step (1), the separator of step (4), and the negative electrode sheet of step (2) are wound to obtain a bare cell without liquid injection; the bare cell is placed in an aluminum-plastic film package, and the electrolyte of step (3) is injected into the dried bare cell. After vacuum packaging, standing, forming, shaping, sorting and other processes, a lithium-ion battery is obtained.

[0152] Test Case

[0153] The batteries obtained in the examples and comparative examples were tested as follows:

[0154] (1) 25℃ cycle test

[0155] The battery was placed in an ambient temperature of (25±3)°C and charged at a constant current of 1C to 4.5V with a cut-off current of 0.05C. After the battery was fully charged, it was placed for 5 minutes and then discharged at a constant current of 0.5C to a cut-off voltage of 3.0V. The highest discharge capacity of the first three cycles was recorded as the initial capacity Q. When the cycle reached the required number of times, the last discharge capacity Q1 of the battery was recorded. The recorded results are shown in Table 2.

[0156] The calculation formula is as follows: Capacity retention rate (%) = Q1 / Q×100%.

[0157] (2) High temperature storage test

[0158] The obtained battery was charged at an ambient temperature of (25±3)°C and the thickness of the battery was measured at 100% SOC (H1). It was then stored at a high temperature of (85±3)°C for 8 hours. After storage, it was allowed to stand at room temperature for 1.5 hours, and the thickness of the battery after storage was measured again (H2).

[0159] The calculation formula is as follows: battery expansion rate (%) = (H2-H1) / H1×100%.

[0160] (3) Overcharge test

[0161] At 20±5°C, charge the battery to 4.6V at the maximum current (3.9C) set in the test software, maintain constant voltage for 7 hours, and then stop the test. The battery is considered passed if it does not catch fire, smoke, or explode. A total of 5 batteries are tested, and the results are expressed as "pass number / 5T", where "5P / 5T" means all 5 tests passed, and "3P / 5T" means 3 out of 5 tests passed.

[0162] (4) Over-discharge test

[0163] At 23±2°C, reverse the battery connection and charge at 1C for 90 minutes, then stop testing. The battery passes if it does not catch fire, smoke, or explode. Five batteries are tested, and the results are expressed as "pass count / 5T." "5P / 5T" means all five tests passed, and "3P / 5T" means three out of five tests passed.

[0164] The obtained results are recorded in Table 2.

[0165] Table 2

[0166] It can be seen from Table 2 that the 25°C capacity retention rate of the battery in the embodiment is significantly improved, the high-temperature storage expansion rate is significantly reduced, the overcharge test pass rate is significantly improved, the over-discharge test pass rate is significantly improved, and the rate performance is significantly improved, indicating that by making the battery meet: 0.25≤(A / (C+L))×100≤25, the cycle stability, high-temperature storage performance and rate performance of the battery are improved.

[0167] The preferred embodiments of the present disclosure are described in detail above, but the present disclosure is not limited thereto. Within the technical concept of the present disclosure, various simple variations of the technical solution of the present disclosure may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed by the present disclosure and fall within the scope of protection of the present disclosure.

Claims

1. A battery, characterized in that, The battery includes an electrolyte and a positive electrode sheet. The electrolyte includes an ether nitrile compound, and the ether nitrile compound includes a compound with the structure NC-M1-O-M2; wherein, M2 is selected from -CN or a group including -O-N1-CN, and M1 and N1 are each independently selected from a substituted or unsubstituted C1-C9 alkyl group, a substituted or unsubstituted C2-C9 alkenyl group, a substituted or unsubstituted C2-C9 alkynyl group, a substituted or unsubstituted C2-C9 ether group; the substituent of the substitution is selected from one or more of halogens; based on the total weight of the electrolyte, the weight content of the ether nitrile compound is Awt%; the positive electrode sheet includes a lithium cobaltate material and carbon nanotubes. The median particle size Dv50 of the lithium cobaltate material is C, with the unit of μm, and the tube diameter of the carbon nanotubes is L, with the unit of nm. Then, the battery satisfies: 0.25 ≤ (A / (C + L))×100 ≤ 25.

2. The battery according to claim 1, wherein The nitrile ether compound is C n -P m and / or has the structure shown in formula (I), where C n is a main chain with a straight-chain structure, n is a positive integer from 1 to 4, P is a graft chain connected to the main chain C, m is a positive integer from 3 to 8, and the graft chains P in the ether polynitrile compound are each independently selected from -R2-O-R1-CN, where T1, T2, R1, and R2 are each independently selected from substituted or unsubstituted C1-C9 alkyl groups, substituted or unsubstituted C2-C9 alkenyl groups, substituted or unsubstituted C2-C9 alkynyl groups, substituted or unsubstituted C2-C9 ether groups, and a null bond, and R1 and R2 are not simultaneously a null bond, and the substituents of the substitution are selected from one or more of halogens; and / or, m > n; and / or, the battery satisfies: 1.1 ≤ (A / (C + L))×100 ≤ 20.

3. The battery according to claim 1 or 2, wherein, The nitrile ether compounds include one or more of the structures represented by formula (Ⅰ), formula (Ⅱ), formula (ⅡⅠ), formula (Ⅳ), formula (Ⅴ) and formula (Ⅵ). Wherein, T1, T2, R3, R4, R5, R6, R7, R8, R9, R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , R 18 , R 19 , R 20 , R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 , R 28 , R 29 , R 30 , R 31 , R 32 , R 33 , R 34 , R 35 , R 36 are each independently selected from substituted or unsubstituted C1-C9 alkyl, substituted or unsubstituted C2-C9 alkenyl, substituted or unsubstituted C2-C9 alkynyl, substituted or unsubstituted C2-C9 ether group, and the substituents of the substituted group are selected from one or more of halogens.

4. The battery according to any one of claims 1-3, wherein, T1, T2, R3, R4, R5, R6, R7, R8, R9, R 10 、R 11 、R 12 、R 13 、R 14 、R 15 、R 16 、R 17 、R 18 、R 19 、R 20 、R 21 、R 22 、R 23 、R 24 、R 25 、R 26 、R 27 、R 28 、R 29 、R 30 、R 31 、R 32 、R 33 、R 34 、R 35 、R 36 each independently selected from substituted or unsubstituted C1-C5 alkyl, substituted or unsubstituted C2-C5 alkenyl, substituted or unsubstituted C2-C5 alkynyl, substituted or unsubstituted C2-C5 ether group; and / or, the substituent of the substitution is selected from F.

5. The battery according to any one of claims 1-4, wherein, The nitrile ether compound includes one or more of the following structures:

6. The battery according to any one of claims 1-5, wherein, Based on the total weight of the electrolyte, the weight content Awt% of the ether nitrile compound is 0.1wt% - 6wt%, preferably 0.2wt% - 3.5wt%.

7. The battery according to any one of claims 1-6, wherein, The electrolyte includes a functional additive, and the functional additive includes one or more of a cyclic carbonate additive, a cyclic sulfonic acid lactone additive, and a lithium salt additive.

8. The battery according to claim 7, wherein, Based on the total weight of the electrolyte, the weight content of the functional additive is 10wt% - 30wt%, preferably 15wt% - 25wt%.

9. The battery according to any one of claims 1-8, wherein, The chemical formula of the lithium cobaltate material is Li x Co z A y1 B y2 C y3 D y4 O2, where 0.95 ≤ x ≤ 1.05, 0 ≤ y1 ≤ 0.1, 0 ≤ y2 ≤ 0.1, 0 ≤ y3 ≤ 0.1, 0 ≤ y4 ≤ 0.1, and 0.6 ≤ z ≤ 1.

10. The battery according to claim 9, wherein, A, B, C, and D are doping elements, and A, B, C, and D each independently include one or more of Al, Mg, Mn, Cr, Ti, Zr, Y, La, B, and Ce. and / or, the surface of the lithium cobaltate has a coating layer.

11. The battery according to claim 10, wherein, The thickness of the coating layer < 50nm; and / or, the coating layer includes one or more of a carbon material, Al2O3, TiO2, ZrO2, MgO, CoO2, CoO, NiO, MnO2, Mn3O4, NbO3, Ta2O5, AlF3, MgF2, CuF2, AlPO3, Li3PO3, lithium lanthanum zirconium oxide (LLZO), lithium aluminum titanium phosphate (LATP), LiCoPO4, Zr3(PO4)4, and Li2PO3F. and / or, based on the total weight of the lithium cobaltate material, the weight content of the coating layer is 0wt% - 5wt%, preferably 0.05wt% - 0.12wt%.

12. The battery according to any one of claims 1-11, wherein, The median particle size Dv50 of the lithium cobaltate material is 8μm - 25μm, preferably 13μm - 18μm.

13. The battery according to claim 1 or 2, wherein, The tube diameter L of the carbon nanotubes is 0.5nm - 15nm; and / or, the carbon nanotubes include one or more of single-walled carbon nanotubes and multi-walled carbon nanotubes; and / or, the carbon nanotubes are single-walled carbon nanotubes.

14. The battery according to claim 13, wherein, The tube diameter L of the single-walled carbon nanotubes is 0.5nm - 2nm; and / or, the aspect ratio of the single-walled carbon nanotubes is 500 - 2000.

15. The battery according to any one of claims 1-14, wherein, The battery is a lithium-ion secondary battery.

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