WO2024066447A1 - 一种电解液和电池 - Google Patents

一种电解液和电池 Download PDF

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Publication number
WO2024066447A1
WO2024066447A1 PCT/CN2023/098200 CN2023098200W WO2024066447A1 WO 2024066447 A1 WO2024066447 A1 WO 2024066447A1 CN 2023098200 W CN2023098200 W CN 2023098200W WO 2024066447 A1 WO2024066447 A1 WO 2024066447A1
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Prior art keywords
lithium
additive
battery
electrolyte
positive electrode
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PCT/CN2023/098200
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English (en)
French (fr)
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邱亚明
王海
李素丽
李俊义
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珠海冠宇电池股份有限公司
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Publication of WO2024066447A1 publication Critical patent/WO2024066447A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0567—Liquid materials characterised by the additives
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/054—Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0088—Composites
    • H01M2300/0091—Composites in the form of mixtures
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present disclosure relates to the technical field of batteries, and in particular to an electrolyte and a battery.
  • Lithium-ion batteries are an indispensable part of various electronic products, electric vehicles, energy storage devices and other application fields. Compared with other energy storage methods, lithium-ion batteries have irreplaceable advantages, such as high energy density and long cycle life. With the rapid development of science and technology, lithium-ion batteries also need to achieve higher and higher energy density. Increasing the voltage of lithium-ion batteries is one of the most important ways.
  • the present disclosure provides an electrolyte and a battery.
  • the present disclosure can form a high-strength CEI (positive electrode electrolyte interface) rich in inorganic matter by oxidative decomposition of electrolyte additives at the positive electrode, thereby greatly reducing the side reactions of oxidative decomposition of the electrolyte and reducing the loss of positive electrode active materials under high temperature and high pressure, thereby achieving the improvement of high temperature and high pressure performance of the battery, and improving the cycle stability and high temperature stability of the battery.
  • CEI positive electrode electrolyte interface
  • the present disclosure provides an electrolyte solution, which includes an organic solvent, an electrolyte salt and an additive A;
  • the additive A is selenocyanate.
  • the additive A selenocyanate in the electrolyte provided by the present invention can be oxidatively decomposed at the positive electrode to form a high-strength CEI rich in non-polar materials, thereby greatly reducing the side reactions of the oxidative decomposition of the electrolyte and reducing the loss of active materials at the positive electrode of the battery under high temperature conditions, thereby improving the stability of the battery and significantly improving the high temperature and high pressure performance of the battery.
  • the selenocyanate is selected from at least one of potassium selenocyanate (KSeCN), sodium selenocyanate (NaSeCN) and lithium selenocyanate (LiSeCN).
  • the selenocyanate plays a role, and the selenocyanate can be oxidized and decomposed at the positive electrode to form CEI, thereby improving the stability of the battery.
  • the selenocyanate is potassium selenocyanate, but other selenocyanates (such as sodium selenocyanate, lithium selenocyanate, etc.) can also play a role in forming CEI.
  • film-forming additives can also be added to the electrolyte to form a passivation protective film on the surface of the positive electrode to reduce the direct contact between the electrolyte and the positive electrode material, but the improvement effect is not significant.
  • additive A can form a uniform passivation film with high mechanical strength, and by adding some substances that can coordinate with transition metals, the direct contact between the electrolyte and the transition metal can be further reduced to further reduce side reactions; further, the passivation film formed by additive A can strengthen the coordination effect between specific substances and transition metals, thereby further reducing side reactions.
  • the electrolyte further comprises an additive B, and the additive B is a trinitrile compound.
  • the additive A selenocyanate is oxidatively decomposed at the positive electrode to form a high-strength CEI rich in non-polar materials, and the additive B polynitrile compound is coordinated with the transition metal, thereby greatly reducing the side reactions of the oxidative decomposition of the electrolyte and reducing the loss of the positive electrode active material of the battery under high temperature conditions, thereby improving the stability of the battery and significantly improving the high temperature and high pressure performance of the battery.
  • the trinitrile compound is selected from glycerol trinitrile, 1,3,6-hexane trinitrile, 1,3,5-pentanetrinitrile At least one of nitrile, 1,2,3-propane tricarbonitrile, 1,2,6-hexane trinitrile, 1,2,3-tri(2-cyanoethoxy)propane, 1,2,4-tri(2-cyanoethoxy)butane, 1,1,1-tri(cyanoethoxymethylene)ethane, 1,1,1-tri(cyanoethoxymethylene)propane, 3-methyl-1,3,5-tri(cyanoethoxy)pentane, 1,2,7-tri(cyanoethoxy)heptane, 1,2,6-tri(cyanoethoxy)hexane and 1,2,5-tri(cyanoethoxy)pentane.
  • the trinitrile compound is glycerol trinitrile and/or 1,3,6-hexane trinitrile, but other trinitrile compounds can also play a role in coordinating with the transition metal.
  • the trinitrile compound is selected from at least one of glycerol trinitrile and 1,3,6-hexane trinitrile.
  • Glycerol trinitrile and/or 1,3,6-hexane trinitrile are relatively more stable and have better improvement on high voltage performance.
  • the content of additive A in the electrolyte is 0.1wt% to 2wt%, for example, 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1wt%, 1.1wt%, 1.2wt%, 1.3wt%, 1.4wt%, 1.5wt%, 1.6wt%, 1.7wt%, 1.8wt%, 1.9wt%, 2wt%, preferably, the content of additive A is 0.2wt% to 1.5wt%. If the content of additive A is too low, the effect is not obvious, and if the content is too high, it is easy to precipitate and affect the battery performance.
  • the content of the additive B is 0.1wt% to 5wt%; for example, 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1wt%, 1.1wt%, 1.2wt%, 1.3wt%, 1.4wt%, 1.5wt%, 1.6wt%, 1.7wt%, 1.8wt%, 1.9wt%, 2wt%, 2.2wt%, 2.4wt%, 2.5wt%, 2.6wt%, 2.8wt%, 3wt%, 3.3wt%, 3.5wt%, 3.8wt%, 4wt%, 4.2wt%, 4.5wt%, 4.8wt% or 5wt%; in the specific embodiment provided in the present disclosure, the content of the additive B is 2wt% to 4wt%. If the content of additive B is 2w
  • the electrolyte salt is a lithium salt or a sodium salt.
  • the lithium salt is selected from lithium hexafluorophosphate (LiPF 6 ), lithium difluorophosphate (LiPO 2 F 2 ), lithium difluorooxalatoborate (LiDFOB), lithium bis(fluorosulfonyl)imide (LiTFSI), lithium bis(trifluoromethylsulfonyl)imide, lithium difluorobis(oxalatophosphate), lithium tetrafluoroborate, lithium bis(oxalatoborate), hexafluorophosphate, lithium difluorophosphate, lithium difluoroborate, lithium difluoroborate, lithium difluorophosphate ...
  • the sodium salt is selected from at least one of NaPF 6 , NaClO 4 , NaAlCl 4 , NaFeCl 4 , NaSO 3 CF 3 , NaBCl 4 , NaNO 3 , NaPOF 4 , NaSCN, NaCN, NaAsF 6 , NaCF 3 CO 2 , NaSbF 6 , NaC 6 H 5 CO 2 , Na(CH 3 )C 6 H 4 SO 3 , NaHSO 4 and NaB(C 6 H 5 ) 4 .
  • the content of electrolyte salt in the electrolyte is 11 wt% to 18 wt%, for example, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt% or 18 wt%.
  • the organic solvent includes carbonate and/or carboxylate.
  • the carbonate is selected from at least one of the following solvents and fluorinated products thereof: ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate, diethyl carbonate (DEC) and ethyl methyl carbonate.
  • EC ethylene carbonate
  • PC propylene carbonate
  • DEC diethyl carbonate
  • ethyl methyl carbonate ethylene carbonate
  • solvents and fluorinated products thereof ethylene carbonate
  • PC propylene carbonate
  • DEC diethyl carbonate
  • ethyl methyl carbonate ethyl methyl carbonate
  • the carboxylic acid ester is selected from at least one of the following solvents and their fluorinated derivatives: propyl acetate, n-butyl acetate, isobutyl acetate, n-pentyl acetate, isopentyl acetate, propyl propionate (PP), ethyl propionate (EP), methyl butyrate and ethyl butyrate.
  • solvents and their fluorinated derivatives propyl acetate, n-butyl acetate, isobutyl acetate, n-pentyl acetate, isopentyl acetate, propyl propionate (PP), ethyl propionate (EP), methyl butyrate and ethyl butyrate.
  • the electrolyte further comprises an additive C, and the additive C is selected from at least one of cyclic carbonate additives, cyclic sultone additives, nitrile additives and lithium salt additives.
  • the additive C is selected from at least one of cyclic carbonate additives, cyclic sultone additives, nitrile additives and lithium salt additives.
  • the cyclic carbonate additive includes at least one of fluoroethylene carbonate, vinylene carbonate and vinylethylene carbonate.
  • the cyclic carbonate additive is fluoroethylene carbonate.
  • the cyclic sultone additive is at least one selected from 1,3-propane sultone, 1,3-propylene sultone, 2,4-butane sultone and 1,4-butane sultone.
  • the cyclic sultone additive is selected from at least one of 1,3-propane sultone and 1,3-propene sultone.
  • the nitrile additive is selected from succinonitrile, adiponitrile, glutaronitrile, 1,5-dicyanopentane, 1,6-Dicyanohexane, 1,7-Dicyanoheptane, 1,8-Dicyanooctane, 1,9-Dicyanononane, 1,10-Dicyanodecane, 1,12-Dicyanododecane, tetramethylsuccinonitrile, 2-methylglutaronitrile, 2,4-dimethylglutaronitrile, 2,2,4,4-tetramethylglutaronitrile, 1,4-dicyanopentane, 2,6-dicyanoheptane, 2,7-dicyanooctane, 2,8-dicyanononane, 1,6-dicyanodecane, 1,2-dicyanobenzene, 1,3-dicyanobenzene, 1,4-dicyanobenzene, 3,5-di
  • the nitrile additive is selected from at least one of succinonitrile and adiponitrile.
  • the lithium salt additive is selected from at least one of lithium difluorooxalatoborate, lithium difluorophosphate, lithium difluorobisoxalatophosphate and lithium dioxalatoborate.
  • the content of additive C in the electrolyte is less than or equal to 15wt%, for example, 0.001wt%, 0.005wt%, 0.01wt%, 0.05wt%, 0.1wt%, 0.5wt%, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt% or 15wt%.
  • the present disclosure also provides a battery, which includes the above-mentioned electrolyte.
  • the battery includes a lithium ion battery and/or a sodium ion battery.
  • the battery further includes a positive electrode sheet, a negative electrode sheet and a separator.
  • the battery is a lithium-ion battery.
  • the battery is a high voltage battery.
  • the charging cut-off voltage of the battery is above 4.48V, for example, 4.5V or 4.53V.
  • the charging cut-off voltage of the battery is above 4.5V.
  • the battery is a high High-voltage lithium cobalt oxide battery, high-voltage ternary battery or high-voltage lithium-manganese-rich battery.
  • the battery is a high voltage lithium cobalt oxide battery.
  • the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer coated on at least one side of the positive electrode current collector, and the positive electrode active material layer includes a positive electrode active material, a conductive agent and a binder.
  • the mass percentage of each component in the positive electrode active material layer is: 80wt% to 99.8wt% of the positive electrode active material, 0.1wt% to 10wt% of the conductive agent and 0.1wt% to 10wt% of the binder.
  • the mass percentage of each component in the positive electrode active material layer is: 90wt% to 99.6wt% of the positive electrode active material, 0.2wt% to 5wt% of the conductive agent and 0.2wt% to 5wt% of the binder.
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer coated on at least one side of the negative electrode current collector, and the negative electrode active material layer includes a negative electrode active material, the conductive agent and the binder.
  • the mass percentage of each component in the negative electrode active material layer is: 80wt% to 99.8wt% of the negative electrode active material, 0.1wt% to 10wt% of the conductive agent and 0.1wt% to 10wt% of the binder.
  • the mass percentage of each component in the negative electrode active material layer is: 90wt% to 99.6wt% of the negative electrode active material, 0.2wt% to 5wt% of the conductive agent and 0.2wt% to 5wt% of the binder.
  • the conductive agent is selected from at least one of conductive carbon black, acetylene black, Ketjen black, conductive graphite, conductive carbon fiber, carbon nanotubes, metal powder and carbon fiber.
  • the binder is selected from at least one of sodium carboxymethyl cellulose, styrene-butadiene latex, polytetrafluoroethylene and polyethylene oxide.
  • the positive electrode active material is selected from one or more of transition metal lithium oxide, lithium iron phosphate and lithium-rich manganese-based materials; the chemical formula of the transition metal lithium oxide is Li1 +xNiyCozM ( 1-yz) O2 , wherein -0.1 ⁇ x ⁇ 1; 0 ⁇ y ⁇ 1, 0 ⁇ z ⁇ 1, and 0 ⁇ y+z ⁇ 1; wherein M is one or more of Mg, Zn, Ga, Ba, Al, Fe, Cr, Sn, V, Mn, Sc, Ti, Nb, Mo and Zr.
  • the negative electrode active material includes a carbon-based negative electrode material.
  • the carbon-based negative electrode material includes at least one of artificial graphite, natural graphite, mesophase carbon microbeads, hard carbon and soft carbon.
  • the negative electrode active material may further include a silicon-based negative electrode material.
  • the silicon-based negative electrode material is selected from at least one of nano-silicon, silicon-oxygen negative electrode material (SiO x (0 ⁇ x ⁇ 2)) or silicon-carbon negative electrode material.
  • the mass ratio of the carbon-based negative electrode material to the silicon-based negative electrode material is (10:0) to (1:19), for example, 1:19, 1:18, 1:17, 1:16, 1:15, 1:14, 1:13, 1:12, 1:11, 1:10, 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2, 9:1 or 10:0.
  • the mass ratio of the carbon-based negative electrode material to the silicon-based negative electrode material is 10:0, which means that the silicon-based negative electrode material is not included in the negative electrode active material.
  • the battery further includes an outer packaging.
  • the preparation method of the battery is: stacking the positive electrode sheet, the isolation membrane and the negative electrode sheet to obtain a battery core, or stacking the positive electrode sheet, the isolation membrane and the negative electrode sheet and then winding them to obtain a battery core, placing the battery core in an outer package, and injecting electrolyte into the outer package to obtain the battery of the present disclosure.
  • the present invention has the following beneficial effects:
  • the electrolyte and the battery including the electrolyte provided by the present disclosure can form a high-strength CEI rich in non-polar materials through the oxidation and decomposition of the additive A selenocyanate at the positive electrode, and at the same time can coordinate with the transition metal through the additive B polynitrile compound, thereby greatly reducing the side reaction of the oxidation and decomposition of the electrolyte, and reducing the loss of the positive electrode active material of the battery under high temperature conditions, thereby improving the stability of the battery and significantly improving the high temperature and high pressure performance of the battery; the electrolyte obtained by adding additives A and additive B is more suitable for high voltage battery system, thereby increasing battery energy density.
  • Additive C mainly improves the negative electrode stability of the electrolyte through negative electrode film formation and can further enhance the positive electrode protection effect.
  • the present disclosure discloses an electrolyte and a battery.
  • Those skilled in the art can refer to the content of this article and appropriately improve the process parameters to achieve it. It is particularly important to point out that all similar substitutions and modifications are obvious to those skilled in the art, and they are all deemed to be included in the present disclosure.
  • the methods and applications of the present disclosure have been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit and scope of the present invention to implement and apply the technology disclosed in the present disclosure.
  • the batteries of Examples 1 to 9 and Comparative Examples 1 to 2 were prepared by the following steps:
  • the positive electrode active materials lithium cobalt oxide (LiCoO 2 ), polyvinylidene fluoride (PVDF), SP (super P) and carbon nanotubes (CNT) are mixed in a mass ratio of 96:2:1.5:0.5, N-methylpyrrolidone (NMP) is added, and the mixture is stirred under the action of a vacuum stirrer until the mixed system becomes a positive electrode active slurry with uniform fluidity; the positive electrode active slurry is evenly coated on both surfaces of an aluminum foil; the coated aluminum foil is dried, and then rolled and cut to obtain the desired positive electrode sheet.
  • NMP N-methylpyrrolidone
  • the negative electrode active materials artificial graphite, sodium carboxymethyl cellulose (CMC-Na), styrene-butadiene rubber, conductive carbon black (SP) and single-walled carbon nanotubes (SWCNTs) were mixed in a mass ratio of 96:1.5:1.5:0.95:0.05, and deionized water was added to obtain a negative electrode active slurry under the action of a vacuum mixer; the negative electrode active slurry was evenly coated on both surfaces of the copper foil; the coated copper foil was dried at room temperature and then transferred to an oven at 80°C for drying. 10h, and then cold pressed and cut to obtain the negative electrode sheet.
  • EC/PC/DEC/PP were mixed uniformly in a mass ratio of 10/20/40/30, and then 14.5wt% of fully dried lithium hexafluorophosphate (LiPF 6 ) based on the total mass of the electrolyte was quickly added thereto, and after dissolution, 8wt% of fluoroethylene carbonate (additive C 1 ) based on the total mass of the electrolyte, 2wt% of 1,3-propane sultone (additive C 2 ), 2wt% of succinonitrile (additive C 3 ), and the additives described in Table 1 were added, and the mixture was stirred uniformly. After passing the moisture and free acid tests, the desired electrolyte was obtained.
  • additive C 1 fluoroethylene carbonate
  • additive C 2 1,3-propane sultone
  • additive C 3 succinonitrile
  • the positive electrode sheet of step 1), the negative electrode sheet of step 2) and the separator are stacked in the order of positive electrode sheet, separator and negative electrode sheet, and then wound to obtain a battery cell; the battery cell is placed in an outer packaging aluminum foil, and the electrolyte of step 3) is injected into the outer packaging, and the battery is obtained through vacuum packaging, standing, forming, shaping, sorting and other processes.
  • the charge and discharge range of the disclosed battery is 3.0V-4.5V (i.e., the starting voltage is 3.0V and the end voltage is 4.5V) and 3.0V-4.53V (the starting voltage is 3.0V and the end voltage is 4.53V).
  • the batteries obtained in the above-mentioned embodiments and comparative examples were subjected to a 60°C high temperature storage performance test and a 45°C cycle performance test, respectively.
  • the test results are shown in Tables 2 and 3.
  • the batteries obtained in the above examples and comparative examples were charged at 25°C at a rate of 1C to a cut-off voltage, a cut-off current of 0.025C, and left to stand for 5 minutes.
  • the thickness of the lithium-ion battery was tested (this was the thickness before storage).
  • the fully charged battery cell/battery was placed in an open circuit at (60 ⁇ 2)°C for 35 days. After 35 days of storage, it was placed in an open circuit at room temperature for 2 hours.
  • the batteries obtained in the above embodiments and comparative examples were charged and discharged at 45°C at a rate of 1C within the charge and discharge cut-off voltage range, with a cut-off current of 0.025C.
  • the discharge capacity of the first week of the test was calculated as x 2 mAh, and the discharge capacity of the Nth cycle was calculated as y 2 mAh.
  • Example 1 in which potassium selenocyanate is added alone, the storage thickness expansion rate at 60°C is significantly smaller than that in Comparative Example 1, and the cycle capacity retention rate at 45°C is 80% and the number of cycles is also significantly larger than that in Comparative Example 1.
  • the electrolyte disclosed in the present invention to which selenocyanate and trinitrile compounds are added simultaneously can form a high-strength CEI rich in non-polar substances through selenocyanate oxidation decomposition at the positive electrode, and can also coordinate with the transition metal through the polynitrile compound, thereby greatly reducing the side reactions of the oxidative decomposition of the electrolyte and reducing the loss of the positive electrode active material of the battery under high temperature conditions, thereby improving the stability of the battery and significantly improving the high temperature and high pressure performance of the battery.

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Abstract

本公开涉及电池技术领域，具体涉及一种电解液和电池。该电解液包括有机溶剂、电解质盐和添加剂A；所述添加剂A为硒氰酸盐。本公开通过电解液添加剂在正极氧化分解形成富含无极质的高强度的CEI，同时可以通过添加剂B多腈化合物与过渡金属配位，从而大幅减少电解液的氧化分解的副反应，并降低高温高压下正极活性物质的损失，从而实现了电池高温高压性能的提升，提升了电池的循环稳定性和高温稳定性。

Description

一种电解液和电池 技术领域
本公开涉及电池技术领域，具体涉及一种电解液和电池。
背景技术
锂离子电池是各类电子产品、电动车辆、储能装置等应用领域不可或缺的部分，锂离子电池相对其他储能方法具备不可替代的优点，其具有高能量密度，长循环寿命等。科技发展日新月异，锂离子电池也需要实现愈来愈高的能量密度，提高锂离子电池的电压是最重要的途径之一。
目前商业化的消费类锂离子电池电压大部分为4.45V或更低，少部分产品已经高达4.48V。下一代的锂离子电池电压需要进一步提升到4.5V以上，在更高电压下，碳酸酯类和羧酸酯类作为主溶剂的商业化电解液更易氧化分解，因此电池的高温循环和高温存储性能更加难以满足商业化需求。为了实现4.5V以上锂离子电池的广泛商业化应用，需要开发有效的新型电解液添加剂，实现改善高电压锂离子电池的循环稳定性和高温性能的目的，从而实现4.5V高能量密度电池大规模商业化。
因此，开发一种能够改善4.5V以上高电压锂离子电池的循环和高温性能、减少电解液在正极侧的氧化分解的电解液，具有重要的现实意义。
发明内容
有鉴于此，本公开提供了一种电解液和电池。本公开可以通过电解液添加剂在正极氧化分解形成富含无机质的高强度的CEI(正极电解液界面)，从而大幅减少电解液的氧化分解的副反应，并降低高温高压下正极活性物质的损失，从而实现了电池高温高压性能的提升，提升了电池的循环稳定性和高温稳定性。
为了实现上述发明目的，本公开提供以下技术方案：
本公开提供了一种电解液，该电解液包括有机溶剂、电解质盐和添加剂A； 所述添加剂A为硒氰酸盐。
本公开提供的电解液中添加剂A硒氰酸盐可在正极氧化分解形成富含无极质的高强度的CEI，从而大幅减少电解液的氧化分解的副反应，并降低高温条件下电池正极活性物质的损失，从而提升电池的稳定性，显著改善电池的高温高压性能。
作为优选，所述硒氰酸盐选自硒氰酸钾(KSeCN)、硒氰酸钠(NaSeCN)和硒氰酸锂(LiSeCN)中的至少一种。在硒氰酸盐中起作用的是硒氰基，硒氰基可在正极氧化分解形成CEI，从而提升电池的稳定性。在本公开具体实施例中，所述硒氰酸盐为硒氰酸钾，但其它硒氰酸盐(如硒氰酸钠、硒氰酸锂等)可同样起到形成CEI的作用。
电解液在高电压条件下，需要面临正极表面高价过渡金属的强氧化作用，而高温会明显加剧副反应强度。目前，除了通过正极包覆和掺杂等方法改善正极本身对电解液的氧化分解，还可以在电解液中加入成膜添加剂，从而在正极表面形成一层钝化保护膜来减少电解液和正极材料的直接接触，但是改善效果并不显著。本发明的发明人发现，添加剂A的加入可以形成均匀且具有较高机械强度的钝化膜，并且通过加入一些可以和过渡金属配位的物质，能够进一步减少电解液和过渡金属的直接接触，来进一步降低副反应；进一步地，添加剂A所形成的钝化膜可以强化特定物质与过渡金属的配位作用，从而更进一步地降低副反应。
作为优选，所述电解液还包括添加剂B，所述添加剂B为三腈化合物。
当本公开提供的电解液包括添加剂A和添加剂B时，通过添加剂A硒氰酸盐在正极氧化分解形成富含无极质的高强度的CEI，同时通过添加剂B多腈化合物与过渡金属配位，从而大幅减少电解液的氧化分解的副反应，并降低高温条件下电池正极活性物质的损失，从而提升电池的稳定性，显著改善电池的高温高压性能。
作为优选，所述三腈化合物选自甘油三腈、1,3,6-己烷三腈、1,3,5-戊三甲 腈、1,2,3-丙三甲腈、1,2,6-己烷三腈、1,2,3-三(2-氰基乙氧基)丙烷、1,2,4-三(2-氰基乙氧基)丁烷、1,1,1-三(氰基乙氧基亚甲基)乙烷、1,1,1-三(氰基乙氧基亚甲基)丙烷、3-甲基-1,3,5-三(氰基乙氧基)戊烷、1,2,7-三(氰基乙氧基)庚烷、1,2,6-三(氰基乙氧基)己烷和1,2,5-三(氰基乙氧基)戊烷中的至少一种。在三腈化合物中起作用的是三个腈基，三个腈基与过渡金属配位，从而提升电池的稳定性。在本公开具体实施例中，所述三腈化合物为甘油三腈和/或1,3,6-己烷三腈，但其它三腈化合物可同样起到与过渡金属配位的作用。
优选地，所述三腈化合物选自甘油三腈和1,3,6-己烷三腈中的至少一种。甘油三腈和/或1,3,6-己烷三腈相对更加稳定，对高电压性能改善更佳。
作为优选，所述电解液中添加剂A的含量为0.1wt％～2wt％；例如为0.1wt％、0.2wt％、0.3wt％、0.4wt％、0.5wt％、0.6wt％、0.7wt％、0.8wt％、0.9wt％、1wt％、1.1wt％、1.2wt％、1.3wt％、1.4wt％、1.5wt％、1.6wt％、1.7wt％、1.8wt％、1.9wt％、2wt％；优选地，所述添加剂A的含量为0.2wt％～1.5wt％。添加剂A含量过低效果不明显，含量过高则容易析出沉淀影响电池性能。
作为优选，所述添加剂B的含量为0.1wt％～5wt％；例如为0.1wt％、0.2wt％、0.3wt％、0.4wt％、0.5wt％、0.6wt％、0.7wt％、0.8wt％、0.9wt％、1wt％、1.1wt％、1.2wt％、1.3wt％、1.4wt％、1.5wt％、1.6wt％、1.7wt％、1.8wt％、1.9wt％、2wt％、2.2wt％、2.4wt％、2.5wt％、2.6wt％、2.8wt％、3wt％、3.3wt％、3.5wt％、3.8wt％、4wt％、4.2wt％、4.5wt％、4.8wt％或5wt％；在本公开提供的具体实施例中，所述添加剂B的含量为2wt％～4wt％。添加剂B含量过低，与过渡金属配位覆盖过少，起不到较好改善效果；含量过高则导致阻抗较大。
作为优选，所述电解质盐为锂盐或钠盐。
在本公开提供的具体实施例中，所述锂盐选自六氟磷酸锂(LiPF6)、二氟磷酸锂(LiPO2F2)、二氟草酸硼酸锂(LiDFOB)、双氟磺酰亚胺锂(LiTFSI)、双三氟甲基磺酰亚胺锂、二氟双草酸磷酸锂、四氟硼酸锂、双草酸硼酸锂、六 氟锑酸锂、六氟砷酸锂、二(三氟甲基磺酰)亚胺锂、二(五氟乙基磺酰)亚胺锂、三(三氟甲基磺酰)甲基锂或二(三氟甲基磺酰)亚胺锂中的至少一种。
在本公开提供的具体实施例中，所述钠盐选自NaPF6、NaClO4、NaAlCl4、NaFeCl4、NaSO3CF3、NaBCl4、NaNO3、NaPOF4、NaSCN、NaCN、NaAsF6、NaCF3CO2、NaSbF6、NaC6H5CO2、Na(CH3)C6H4SO3、NaHSO4和NaB(C6H5)4中的至少一种。
作为优选，所述电解液中电解质盐的含量为11wt％～18wt％，例如为11wt％、12wt％、13wt％、14wt％、15wt％、16wt％、17wt％或18wt％。
在本公开提供的具体实施例中，所述有机溶剂包括碳酸酯和/或羧酸酯。
作为优选，所述碳酸酯选自下述溶剂及其氟代物中的至少一种：碳酸乙烯酯(EC)、碳酸丙烯酯(PC)、碳酸二甲酯、碳酸二乙酯(DEC)和碳酸甲乙酯。
作为优选，所述羧酸酯选自下述溶剂及其氟代物中的至少一种：乙酸丙酯、乙酸正丁酯、乙酸异丁酯、乙酸正戊酯、乙酸异戊酯、丙酸丙酯(PP)、丙酸乙酯(EP)、丁酸甲酯和正丁酸乙酯。
作为优选，所述电解液还包括添加剂C，所述添加剂C选自环状碳酸酯类添加剂、环状磺酸内酯类添加剂、腈类添加剂和锂盐型添加剂中的至少一种。
作为优选，所述环状碳酸酯类添加剂包括氟代碳酸乙烯酯、碳酸亚乙烯酯和碳酸乙烯亚乙酯中的至少一种。
在本公开提供的具体实施例中，所述环状碳酸酯类添加剂为氟代碳酸乙烯酯。
优选地，所述环状磺酸内酯类添加剂选自1,3-丙烷磺酸内酯、1,3-丙烯磺酸内酯、2,4-丁烷磺内酯和1,4-丁磺酸内酯中的至少一种。
在本公开提供的具体实施例中，所述环状磺酸内酯类添加剂选自1,3-丙烷磺酸内酯和1,3-丙烯磺酸内酯中的至少一种。
优选地，所述腈类添加剂选自丁二腈、己二腈、戊二腈、1,5-二氰基戊烷、 1,6-二氰基己烷、1,7-二氰基庚烷、1,8-二氰基辛烷、1,9-二氰基壬烷、1,10-二氰基癸烷、1,12-二氰基十二烷、四甲基丁二腈、2-甲基戊二腈、2,4-二甲基戊二腈、2,2,4,4-四甲基戊二腈、1,4-二氰基戊烷、2,6-二氰基庚烷、2,7-二氰基辛烷、2,8-二氰基壬烷、1,6-二氰基癸烷、1,2-二氰基苯、1,3-二氰基苯、1,4-二氰基苯、3,5-二氧杂-庚二腈、1,4-二(氰基乙氧基)丁烷、乙二醇二(2-氰基乙基)醚、二乙二醇二(2-氰基乙基)醚、三乙二醇二(2-氰基乙基)醚、四乙二醇二(2-氰基乙基)醚、3,6,9,12,15,18-六氧杂二十烷酸二腈、1,3-二(2-氰基乙氧基)丙烷、1,4-二(2-氰基乙氧基)丁烷、1,5-二(2-氰基乙氧基)戊烷、乙二醇二(4-氰基丁基)醚、1,4-二氰基-2-丁烯、1,4-二氰基-2-甲基-2-丁烯、1,4-二氰基-2-乙基-2-丁烯、1,4-二氰基-2,3-二甲基-2-丁烯、1,4-二氰基-2,3-二乙基-2-丁烯、1,6-二氰基-3-己烯、1,6-二氰基-2-甲基-3-己烯和1,6-二氰基-2-甲基-5-甲基-3-己烯中的至少一种。
在本公开提供的具体实施例中，所述腈类添加剂选自丁二腈和己二腈中的至少一种。
优选地，所述锂盐型添加剂选自二氟草酸硼酸锂、二氟磷酸锂、二氟二草酸磷酸锂和二草酸硼酸锂中的至少一种。
作为优选，所述电解液中添加剂C的含量小于等于15wt％，例如为0.001wt％、0.005wt％、0.01wt％、0.05wt％、0.1wt％、0.5wt％、1wt％、2wt％、3wt％、4wt％、5wt％、6wt％、7wt％、8wt％、9wt％、10wt％、11wt％、12wt％、13wt％、14wt％或15wt％。
本公开还提供了一种电池，该电池包括上述电解液。
所述电池包括锂离子电池和/或钠离子电池。
在本公开提供的具体实施例中，所述电池还包括正极片、负极片和隔离膜。
作为优选，所述电池为锂离子电池。
优选地，所述电池为高电压电池。在本公开提供的具体实施例中，所述电池的充电截止电压为4.48V以上，例如，4.5V或4.53V。在本公开提供的具体实施例中，所述电池的充电截止电压为4.5V以上。示例性地，所述电池为高 电压钴酸锂电池、高电压三元电池或者高电压富锂锰基电池。
更优选地，所述电池为高电压钴酸锂电池。
在本公开提供的具体实施例中，所述正极片包括正极集流体和涂覆在所述正极集流体至少一侧表面的正极活性物质层，所述正极活性物质层包括正极活性物质、导电剂和粘结剂。
在本公开提供的具体实施例中，所述正极活性物质层中各组分的质量百分含量为：80wt％～99.8wt％的所述正极活性物质、0.1wt％～10wt％的所述导电剂和0.1wt％～10wt％的所述粘结剂。
优选地，所述正极活性物质层中各组分的质量百分含量为：90wt％～99.6wt％的所述正极活性物质、0.2wt％～5wt％的所述导电剂和0.2wt％～5wt％的所述粘结剂。
在本公开提供的具体实施例中，所述负极片包括负极集流体和涂覆在所述负极集流体至少一侧表面的负极活性物质层，所述负极活性物质层包括负极活性物质、所述导电剂和所述粘结剂。
在本公开提供的具体实施例中，所述负极活性物质层中各组分的质量百分含量为：80wt％～99.8wt％的所述负极活性物质、0.1wt％～10wt％的所述导电剂和0.1wt％～10wt％的所述粘结剂。
优选地，所述负极活性物质层中各组分的质量百分含量为：90wt％～99.6wt％的所述负极活性物质、0.2wt％～5wt％的所述导电剂和0.2wt％～5wt％的所述粘结剂。
在本公开提供的具体实施例中，所述导电剂选自导电炭黑、乙炔黑、科琴黑、导电石墨、导电碳纤维、碳纳米管、金属粉和碳纤维中的至少一种。
在本公开提供的具体实施例中，所述粘结剂选自羧甲基纤维素钠、丁苯胶乳、聚四氟乙烯和聚氧化乙烯中的至少一种。
在本公开提供的具体实施例中，所述正极活性材料选自过渡金属锂氧化物、磷酸铁锂和富锂锰基材料中的一种或几种；所述过渡金属锂氧化物的化学式为 Li1+xNiyCozM(1-y-z)O2，其中，-0.1≤x≤1；0≤y≤1，0≤z≤1，且0≤y+z≤1；其中，M为Mg、Zn、Ga、Ba、Al、Fe、Cr、Sn、V、Mn、Sc、Ti、Nb、Mo和Zr中的一种或几种。
在本公开提供的具体实施例中，所述负极活性物质包括碳基负极材料。
在本公开提供的具体实施例中，所述碳基负极材料包括人造石墨、天然石墨、中间相碳微球、硬碳和软碳中的至少一种。
在本公开提供的具体实施例中，所述负极活性物质还可进一步包括硅基负极材料。
在本公开提供的具体实施例中，所述硅基负极材料选自纳米硅、硅氧负极材料(SiOx(0<x<2))或者硅碳负极材料中的至少一种。
在本公开提供的具体实施例中，所述负极活性物质中，所述碳基负极材料和所述硅基负极材料的质量比为(10:0)～(1:19)，例如为1:19、1:18、1:17、1:16、1:15、1:14、1:13、1:12、1:11、1:10、1:9、2:8、3:7、4:6、5:5、6:4、7:3、8:2、9:1或10:0。其中，所述碳基负极材料和所述硅基负极材料的质量比为10:0指的是：在所述负极活性物质中，不包括所述硅基负极材料。
在本公开提供的具体实施例中，所述电池还包括外包装。
在本公开提供的具体实施例中，所述电池的制备方法为：将正极片、隔离膜和负极片层叠设置得到电芯，或将正极片、隔离膜和负极片层叠设置后再进行卷绕设置得到电芯，将所述电芯置于外包装中，向所述外包装中注入电解液，得到本公开的电池。
与现有技术相比，本公开具有的有益效果为：
本公开提供的电解液及包括该电解液的电池可以通过添加剂A硒氰酸盐在正极氧化分解形成富含无极质的高强度的CEI，同时可以通过添加剂B多腈化合物与过渡金属配位，从而大幅减少电解液的氧化分解的副反应，并降低高温条件下电池正极活性物质的损失，从而提升电池的稳定性，显著改善电池的高温高压性能；通过添加添加剂A和添加剂B所得的电解液更适用于高电压 电池体系，从而提高电池能量密度。
添加剂C主要通过负极成膜改善电解液负极稳定性，并可进一步增强正极保护效果。
具体实施方式
本公开公开了一种电解液和电池，本领域技术人员可以借鉴本文内容，适当改进工艺参数实现。特别需要指出的是，所有类似的替换和改动对本领域技术人员来说是显而易见的，它们都被视为包括在本公开。本公开的方法及应用已经通过较佳实施例进行了描述，相关人员明显能在不脱离本发明内容、精神和范围内对本文所述的方法和应用进行改动或适当变更与组合，来实现和应用本公开技术。
下述实施例中所使用的实验方法如无特殊说明，均为常规方法；下述实施例中所用的试剂、材料等，如无特殊说明，均可从商业途径得到。
下面结合实施例，进一步阐述本公开：
实施例1～9及对比例1～2
实施例1～9及对比例1～2的电池通过以下步骤制备得到：
1)正极片制备
将正极活性材料钴酸锂(LiCoO2)、聚偏氟乙烯(PVDF)、SP(super P)和碳纳米管(CNT)按照96:2:1.5:0.5的质量比进行混合，加入N-甲基吡咯烷酮(NMP)，在真空搅拌机作用下搅拌，直至混合体系成均一流动性的正极活性浆料；将正极活性浆料均匀涂覆于铝箔的两个表面；将涂覆好的铝箔烘干，然后经过辊压、分切得到所需的正极片。
2)负极片制备
将负极活性材料人造石墨、羧甲基纤维素钠(CMC-Na)、丁苯橡胶、导电炭黑(SP)和单壁碳纳米管(SWCNTs)按照质量比96:1.5:1.5:0.95:0.05进行混合，加入去离子水，在真空搅拌机作用下获得负极活性浆料；将负极活性浆料均匀涂覆在铜箔的两个表面；将涂覆好的铜箔在室温下晾干，随后转移至80℃烘箱干燥 10h，然后经过冷压、分切得到负极片。
3)电解液的制备
在充满氩气的手套箱中(H2O＜0.1ppm，O2＜0.1ppm)，将EC/PC/DEC/PP按照10/20/40/30的质量比混合均匀，然后往其中快速加入基于电解液总质量14.5wt％的充分干燥的六氟磷酸锂(LiPF6)，溶解后加入基于电解液总质量8wt％的氟代碳酸乙烯酯(添加剂C1)，2wt％的1,3-丙烷磺内酯(添加剂C2)，2wt％的丁二腈(添加剂C3)，以及表1所述的添加剂，搅拌均匀，经过水分和游离酸检测合格后，得到所需的电解液。
4)电池的制备
将步骤1)的正极片、步骤2)的负极片和隔离膜按照正极片、隔离膜和负极片的顺序层叠设置后，再进行卷绕得到电芯；将电芯置于外包装铝箔中，将步骤3)的电解液注入外包装中，经过真空封装、静置、化成、整形、分选等工序，获得电池。本公开电池充放电范围为3.0V-4.5V(即起始电压为3.0V，截至电压为4.5V)和3.0V-4.53V(起始电压为3.0V，截止电压为4.53V)。
实施例10
与实施例3相比，电解液中未添加氟代碳酸乙烯酯、1,3-丙烷磺内酯和丁二腈。
对比例3
与实施例10相比，电解液中未添加添加剂A。
对比例4
与实施例10相比，电解液中未添加添加剂B。
表1实施例1～9和对比例1～2的电池中电解液添加剂的组成

电池性能测试
对上述实施例和对比例获得的电池分别进行60℃高温存储性能测试，以及45℃循环性能测试，测试结果见表2和表3。
1)60℃存储性能测试
将上述实施例和对比例获得的电池在25℃下按照1C的倍率充电到截止电压，截止电流0.025C，静置5min，测试锂离子电池的厚度(以此为存储前的厚度)。充满电的电芯/电池在(60±2)℃条件下开路搁置35天，储存35天后在室温条件下开路搁置2h，测存储后的冷厚度，计算锂离子电池厚度膨胀率：
厚度膨胀率＝[(存储后厚度-存储前厚度)/存储前厚度]×100％。
2)45℃循环性能测试
将上述实施例和对比例获得的电池在45℃下按照1C的倍率在充放电截止电压范围内进行充放电循环，截止电流0.025C，测试第1周的放电容量计为x2mAh，第N圈的放电容量计为y2mAh；第N周的容量除以第1周的容量，得到第N周的循环容量保持率R2＝y2/x2，当循环容量保持率R2降为80％以下时，记录此时的循环周数。
表2实施例1-9和对比例1-2的电池的性能测试结果

表3实施例10和对比例3-4的电池的性能测试结果
从表2可以看出，没有添加硒氰酸钾添加剂和三腈化合物的对比例1的60℃存储厚度膨胀率要明显大于其他组别，45℃循环容量保持率80％循环圈数要明显小于其他组别。
而单独添加三腈化合物的对比例2，其厚度60℃存储厚度膨胀率要明显大于其他实施例组别，45℃循环容量保持率80％循环圈数也要明显小于其他实施例组别(除实施例1外)。
单独添加硒氰酸钾的实施例1，其厚度60℃存储厚度膨胀率要明显小于对比例1，45℃循环容量保持率80％循环圈数也要明显大于对比例1。
通过实施例2-5可知，当同时添加硒氰酸钾添加剂和三腈化合物，随着硒氰酸钾添加量的增加，60℃存储35天厚度膨胀率在缓慢降低，而45℃循环容量保持率80％循环圈数则先快速增加后缓慢增加。这是由于硒氰酸钾越多，对正极保护越好，所以存储性能更好，但是，大量硒氰酸钾会导致阻抗过大，从而对循环性能改善降低。
通过实施例3、实施例6-7可知，当同时添加硒氰酸钾添加剂和三腈化合物， 随着1,3,6-己烷三腈的增加，60℃存储35天厚度膨胀率在逐渐降低，而45℃循环容量保持率80％循环圈数则先增加后下降。这是由于三腈化合物越多，对正极保护越好，所以存储性能更好，但是，大量三腈化合物会导致阻抗过大，从而对循环性能改善降低。
通过实施例8和9可以看出，无论采用1,3,6-己烷三腈还是甘油三腈，都可以达到类似的效果。
从表3可以看出，在不添加添加剂C的情况下，同时添加硒氰酸钾添加剂和三腈化合物后，60℃存储厚度膨胀率显著降低，45℃循环容量保持率80％循环圈数显著增加。
综上，本公开的同时添加有硒氰酸盐和三腈化合物后的电解液可通过硒氰酸盐在正极氧化分解形成富含无极质的高强度的CEI，同时可以通过多腈化合物与过渡金属配位，从而大幅减少电解液的氧化分解的副反应，并降低高温条件下电池正极活性物质的损失，从而提升电池的稳定性，显著改善电池的高温高压性能。
以上所述仅是本公开的优选实施方式，应当指出，对于本技术领域的普通技术人员来说，在不脱离本公开原理的前提下，还可以做出若干改进和润饰，这些改进和润饰也应视为本公开的保护范围。

Claims (15)

  1. 一种电解液，其特征在于，所述电解液包括有机溶剂、电解质盐和添加剂A；所述添加剂A为硒氰酸盐。
  2. 根据权利要求1所述的电解液，其特征在于，所述硒氰酸盐选自硒氰酸钾、硒氰酸钠和硒氰酸锂中的至少一种。
  3. 根据权利要求1或2所述的电解液，其特征在于，所述硒氰酸盐为硒氰酸钾。
  4. 根据权利要求1-3中任一项所述的电解液，其特征在于，所述电解液还包括添加剂B，所述添加剂B为三腈化合物；
    优选地，所述三腈化合物选自甘油三腈、1,3,6-己烷三腈、1,3,5-戊三甲腈、1,2,3-丙三甲腈、1,2,6-己烷三腈、1,2,3-三(2-氰基乙氧基)丙烷、1,2,4-三(2-氰基乙氧基)丁烷、1,1,1-三(氰基乙氧基亚甲基)乙烷、1,1,1-三(氰基乙氧基亚甲基)丙烷、3-甲基-1,3,5-三(氰基乙氧基)戊烷、1,2,7-三(氰基乙氧基)庚烷、1,2,6-三(氰基乙氧基)己烷和1,2,5-三(氰基乙氧基)戊烷中的至少一种；
    优选地，所述三腈化合物选自甘油三腈和1,3,6-己烷三腈中的至少一种。
  5. 根据权利要求1-4中任一项所述的电解液，其特征在于，所述电解液中所述添加剂A的含量为0.1wt％～2wt％；
    优选地，所述添加剂A的含量为0.2wt％～1.5wt％。
  6. 根据权利要求4或5所述的电解液，其特征在于，所述添加剂B的含量为0.1wt％～5wt％；
    优选地，所述添加剂B的含量为2wt％～4wt％。
  7. 根据权利要求1-6中任一项所述的电解液，其特征在于，所述电解质盐为锂盐或钠盐；
    和/或，所述锂盐选自六氟磷酸锂、二氟磷酸锂、二氟草酸硼酸锂、双氟磺酰亚胺锂、双三氟甲基磺酰亚胺锂、二氟双草酸磷酸锂、四氟硼酸锂、双草酸硼酸锂、六氟锑酸锂、六氟砷酸锂、二(三氟甲基磺酰)亚胺锂、二(五氟乙基磺酰)亚胺锂、三(三氟甲基磺酰)甲基锂或二(三氟甲基磺酰)亚胺锂中的至少一种；
    和/或，所述钠盐选自NaPF6、NaClO4、NaAlCl4、NaFeCl4、NaSO3CF3、NaBCl4、NaNO3、NaPOF4、NaSCN、NaCN、NaAsF6、NaCF3CO2、NaSbF6、 NaC6H5CO2、Na(CH3)C6H4SO3、NaHSO4和NaB(C6H5)4中的至少一种。
  8. 根据权利要求1-7中任一项所述的电解液，其特征在于，所述电解液中所述电解质盐的含量为11wt％～18wt％。
  9. 根据权利要求1-8中任一项所述的电解液，其特征在于，所述有机溶剂包括碳酸酯和/或羧酸酯；
    和/或，所述碳酸酯选自下述溶剂及其氟代物中的至少一种：碳酸乙烯酯、碳酸丙烯酯、碳酸二甲酯、碳酸二乙酯和碳酸甲乙酯；
    和/或，所述羧酸酯选自下述溶剂及其氟代物中的至少一种：乙酸丙酯、乙酸正丁酯、乙酸异丁酯、乙酸正戊酯、乙酸异戊酯、丙酸丙酯、丙酸乙酯、丁酸甲酯和正丁酸乙酯。
  10. 根据权利要求1-9中任一项所述的电解液，其特征在于，所述电解液还包括添加剂C，所述添加剂C选自环状碳酸酯类添加剂、环状磺酸内酯类添加剂、腈类添加剂和锂盐型添加剂中的至少一种；
    优选地，所述电解液中所述添加剂C的含量小于等于15wt％。
  11. 根据权利要求10所述的电解液，其特征在于，所述环状碳酸酯类添加剂包括氟代碳酸乙烯酯、碳酸亚乙烯酯和碳酸乙烯亚乙酯中的至少一种；
    和/或，所述环状磺酸内酯类添加剂选自1,3-丙烷磺酸内酯、1,3-丙烯磺酸内酯、2,4-丁烷磺内酯和1,4-丁磺酸内酯中的至少一种；
    和/或，所述腈类添加剂选自丁二腈、己二腈、戊二腈、1,5-二氰基戊烷、1,6-二氰基己烷、1,7-二氰基庚烷、1,8-二氰基辛烷、1,9-二氰基壬烷、1,10-二氰基癸烷、1,12-二氰基十二烷、四甲基丁二腈、2-甲基戊二腈、2,4-二甲基戊二腈、2,2,4,4-四甲基戊二腈、1,4-二氰基戊烷、2,6-二氰基庚烷、2,7-二氰基辛烷、2,8-二氰基壬烷、1,6-二氰基癸烷、1,2-二氰基苯、1,3-二氰基苯、1,4-二氰基苯、3,5-二氧杂-庚二腈、1,4-二(氰基乙氧基)丁烷、乙二醇二(2-氰基乙基)醚、二乙二醇二(2-氰基乙基)醚、三乙二醇二(2-氰基乙基)醚、四乙二醇二(2-氰基乙基)醚、3,6,9,12,15,18-六氧杂二十烷酸二腈、1,3-二(2-氰基乙氧基)丙烷、1,4-二(2-氰基乙氧基)丁烷、1,5-二(2-氰基乙氧基)戊烷、乙二醇二(4-氰基丁基)醚、1,4-二氰基-2-丁烯、1,4-二氰基-2-甲基-2-丁烯、1,4-二氰基-2-乙基-2-丁烯、1,4-二氰基-2,3-二甲基-2-丁烯、1,4-二氰基-2,3-二乙基-2-丁烯、1,6-二氰基-3-己烯、1,6-二氰基-2-甲基-3-己烯和1,6-二氰基-2-甲基-5-甲基-3-己烯中的至少一种；
    和/或，所述锂盐型添加剂选自二氟草酸硼酸锂、二氟磷酸锂、二氟二草酸磷酸锂和二草酸硼酸锂中的至少一种。
  12. 一种电池，其特征在于，所述电池包括权利要求1-11中任一项所述的电解液。
  13. 根据权利要求12所述的电池，其特征在于，所述电池还包括正极片、负极片和隔离膜；
    和/或，所述电池包括锂离子电池和/或钠离子电池；优选为锂离子电池。
  14. 根据权利要求12或13所述的电池，其特征在于，所述电池为高电压电池；
    和/或，所述电池的充电截止电压为4.5V以上；
    和/或，所述电池为高电压钴酸锂电池、高电压三元电池或者高电压富锂锰基电池；优选为高电压钴酸锂电池。
  15. 根据权利要求13或14所述的电池，其特征在于，所述正极片包括正极集流体和涂覆在所述正极集流体至少一侧表面的正极活性物质层，所述正极活性物质层包括正极活性物质、导电剂和粘结剂；优选地，所述正极活性物质层中各组分的质量百分含量为：80wt％～99.8wt％的所述正极活性物质、0.1wt％～10wt％的所述导电剂和0.1wt％～10wt％的所述粘结剂；
    和/或，所述负极片包括负极集流体和涂覆在所述负极集流体至少一侧表面的负极活性物质层，所述负极活性物质层包括负极活性物质、所述导电剂和所述粘结剂；优选地，所述负极活性物质层中各组分的质量百分含量为：80wt％～99.8wt％的所述负极活性物质、0.1wt％～10wt％的所述导电剂和0.1wt％～10wt％的所述粘结剂。
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