WO2023213329A1 - Electrolyte for lithium-rich manganese-based battery system, preparation method therefor, and lithium-rich manganese-based lithium ion battery containing same - Google Patents

Electrolyte for lithium-rich manganese-based battery system, preparation method therefor, and lithium-rich manganese-based lithium ion battery containing same Download PDF

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WO2023213329A1
WO2023213329A1 PCT/CN2023/097340 CN2023097340W WO2023213329A1 WO 2023213329 A1 WO2023213329 A1 WO 2023213329A1 CN 2023097340 W CN2023097340 W CN 2023097340W WO 2023213329 A1 WO2023213329 A1 WO 2023213329A1
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electrolyte
lithium
carbonate
mass fraction
ethyl
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PCT/CN2023/097340
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French (fr)
Chinese (zh)
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邹志群
曾汉民
李佐球
何巍
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湖北亿纬动力有限公司
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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
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy

Definitions

  • the present application relates to the field of lithium-ion batteries, such as a lithium-rich manganese-based battery system electrolyte, and in particular, a lithium-rich manganese-based battery system electrolyte and its preparation method and a lithium-rich manganese-based lithium ion battery containing the same.
  • lithium-ion batteries such as a lithium-rich manganese-based battery system electrolyte, and in particular, a lithium-rich manganese-based battery system electrolyte and its preparation method and a lithium-rich manganese-based lithium ion battery containing the same.
  • Lithium-rich layered oxides are promising high-energy-density cathode materials for next-generation lithium-ion batteries (LIBs).
  • high operating voltage causes traditional carbonate-based electrolytes to severely decompose on the surface of LLOs, forming an uneven, unstable and unprotected cathode-electrolyte interface (CEI), hindering Li+ diffusion and reducing electrochemical efficiency.
  • CLI cathode-electrolyte interface
  • it is also accompanied by side reactions such as the release of lattice oxygen, dissolution of transition metals (especially manganese), and irreversible structural transformation, which seriously weakens its electrochemical performance.
  • the lithium-rich manganese-based cathode material has a specific capacity of more than 250mAh/g in the range of about 2.0-4.8V, which is its most attractive performance feature. However, it has outstanding problems such as capacity fading and rapid voltage fading. Due to the poor thermal stability of lithium-rich materials, side reactions caused by the release of lattice oxygen and the dissolution of transition metal ions at high temperatures are more serious. Usually, surface coating or surface modification treatment of lithium-rich materials, such as Li 3 PO 4 , V 2 O 5, etc., is used to reduce zero loss and TMs dissolution during the cycle, weaken the interface reaction between the cathode material and the electrolyte, and achieve The effect of suppressing the capacity fading and voltage platform fading of lithium-rich materials. However, it is difficult to achieve uniform coating of the material, and there are still certain defects, making it difficult to effectively prevent the oxidation and decomposition of the electrolyte in the positive electrode.
  • CN 113299996A discloses a non-aqueous electrolyte for lithium-ion batteries with a ternary positive electrode material and a negative silicon-oxygen-carbon composite negative electrode material.
  • the solvent is composed of ethylene carbonate and ethyl methyl carbonate
  • the lithium salt is composed of lithium hexafluorophosphate and bisfluorosulfonyl. It is composed of lithium amine and lithium difluoroxalate borate.
  • the additives are composed of vinylene carbonate, fluoroethylene carbonate, 1,3-propanesultone, ethylene carbonate and lithium difluorophosphate to improve the positive and negative electrodes of the battery.
  • the stability of the film formation effectively inhibits the oxidative decomposition and high-temperature gas production of the positive and negative electrodes, improves the normal and high-temperature cycle life and high-temperature storage performance.
  • the performance improvement cannot be targeted at batteries suitable for lithium-rich manganese-based systems.
  • CN 110112465 A discloses a lithium-rich manganese-based cathode material system battery electrolyte and lithium-ion battery.
  • Additives include fluoroethylene carbonate, thiophene-2-methoxyboronic acid pinacol ester, and bis(2,2,2,-trifluoroethyl)carbonate.
  • the present application provides a lithium-rich manganese-based battery system electrolyte, a preparation method thereof, and a lithium-rich manganese-based lithium ion battery containing the electrolyte.
  • the electrolyte includes an organic solvent, a lithium salt and additives.
  • the additives include silicon-based borate functional additives and 1,3-propanesulfonate. Acid lactone and lithium difluorophosphate.
  • the silicon-based borate ester functional additives in the electrolyte in the embodiments of the present application have positive electrode film formation and HF removal effects, and improve the cycle capacity attenuation and voltage attenuation of the lithium-rich manganese-based battery system.
  • the electrolyte additive The efficiency of lithium insertion; on the other hand, using the above-mentioned film-forming additives that can remove HF and capture surface TMs and 0 functions can achieve a better CEI synergistic protection effect.
  • the silicon-based borate functional additive uses 1,3-propanesultone and lithium difluorophosphate. 1,3-propanesultone assists in film formation at the positive and negative electrodes, and has relatively good thermal stability. High, lithium difluorophosphate participates in the film formation of the positive and negative electrodes.
  • the silicon-based borate functional additives include any one or a combination of at least two of Formulas 1-16, where typical but non-limiting examples of the combination are: The combination of Formula 1 and Formula 2, the combination of Formula 2 and Formula 3, the combination of Formula 3 and Formula 4, the combination of Formula 5 and Formula 6, the combination of Formula 7, Formula 8 and Formula 9, Formula 10, Formula 11, Formula The combination of 12 and Formula 13, the combination of Formula 14 and Formula 2, the combination of Formula 15 and Formula 3, or the combination of Formula 16 and Formula 1, etc.
  • the additive further includes vinylene carbonate.
  • vinylene carbonate forms a film on the negative electrode.
  • the mass fraction of the silicon-based borate functional additive is 0.1-1% in terms of mass fraction, where the mass fraction can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%, etc., but are not limited to the listed values, and other unlisted values within this range are also applicable.
  • the silicon-based borate ester functional additives in the embodiments of this application have dual functions of film formation and HF removal. If the added amount is too small, the CEI film cannot be formed on the positive electrode and cannot achieve a good HF removal effect. Too much added amount will cause just The extreme film formation is too thick and the impedance is too large, resulting in increased performance degradation.
  • the mass fraction of vinylene carbonate in the electrolyte is 0-1%, where the mass fraction can be 0 , 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%, etc., but are not limited to the listed values, other unlisted values within the range are the same Be applicable.
  • vinylene carbonate forms a film on the negative electrode. If the added amount is too small, a dense SEI film cannot be formed, and if the added amount is too large, the impedance will be too high and the gas will be produced at high temperatures.
  • the 1,3-propanesultone accounts for 0.5-3% of the mass fraction of the electrolyte, in terms of mass fraction.
  • the mass fraction may be 0.5%, 0.8%, 1.0%, 1.2%, 1.4%, 1.6%, 1.8%, 2.0%, 2.2%, 2.4%, 2.6%, 2.8% or 3%, etc., but is not limited to those listed Value, other unlisted values within this value range are also applicable.
  • 1,3-propanesultone assists in film formation on the positive and negative electrodes, and has high thermal stability. If the added amount is too small, a dense SEI film cannot be formed on the negative electrode, and if the added amount is too much, excessive film formation will occur. The impedance is large, resulting in reduced cycle performance.
  • the mass fraction of the lithium difluorophosphate in the electrolyte is 0.5-1% in terms of mass fraction, where the mass fraction can be 0.5 %, 0.6%, 0.7%, 0.8%, 0.9% or 1.0%, etc., but are not limited to the listed values, and other unlisted values within this numerical range are also applicable.
  • lithium difluorophosphate participates in the film formation of the positive and negative electrodes. If the added amount is too small, a dense SEI film cannot be formed, and if the added amount is too large, it cannot be completely dissolved.
  • the additive in terms of mass fraction, is 1.1-5%, where the mass fraction can be 1.1%, 1.5%, 2.0%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5%, etc. , but not limited to the listed values, other unlisted values within this range are also applicable.
  • the organic solvent includes cyclic carbonate, chain carbonate and chain carboxylic acid ester.
  • the cyclic carbonate includes any one or a combination of at least two of ethylene carbonate, propylene carbonate, butylene carbonate or fluoroethylene carbonate, wherein the combination is typical but not Limiting examples are: a combination of ethylene carbonate and propylene carbonate, a combination of propylene carbonate and butylene carbonate, or a combination of butylene carbonate and fluoroethylene carbonate, and the like.
  • the chain carbonate includes dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, bis(2,2,2-trifluoroethyl) carbonate or methyltrifluoroethyl carbonate. Any one or a combination of at least two carbonates, wherein typical but non-limiting examples of the combination are: the combination of dimethyl carbonate and diethyl carbonate, the combination of diethyl carbonate and ethyl methyl carbonate, A combination of methyl ethyl carbonate and bis(2,2,2-trifluoroethyl) carbonate or a combination of bis(2,2,2-trifluoroethyl) carbonate and methyltrifluoroethyl carbonate.
  • the chain carboxylic acid esters include ethyl propionate, propyl propionate, butyl propionate, methyl butyrate, ethyl butyrate, ethyl difluoroacetate, and ethyl trifluoroacetate.
  • the cyclic carbonate, chain carbonate and chain carbonate are
  • the mass ratio of carboxylic acid ester is (20-40):(40-70):(10-30), wherein the mass ratio can be 20:70:10, 30:60:10, 40:50:10, 30:50:20, 30:40:30 or 40:40:20, etc., but are not limited to the listed values, and other unlisted values within this range are also applicable.
  • the mass fraction of the organic solvent in the electrolyte is 80-88.8%, where the mass fraction can be 80%, 81 %, 82%, 86%, 84%, 85%, 86%, 87%, 88% or 88.8%, etc., but are not limited to the listed values, and other unlisted values within this numerical range are also applicable.
  • the lithium salt includes any one or a combination of at least two of LiPF 6 , LiFSI, LiBOB or LiBF 4 , where typical but non-limiting examples of the combination are: LiPF 6 combination with LiFSI, LiFSI with LiBOB or LiBOB with LiBF 4 .
  • the mass fraction of the electrolyte is 100%
  • the mass fraction of the lithium salt in the electrolyte is 10-15%, where the mass fraction can be 10%, 11 %, 12%, 13%, 14% or 15%, etc., but are not limited to the listed values, and other unlisted values within this numerical range are also applicable.
  • the second object of the present application is to provide a method for preparing the electrolyte according to the first object.
  • the preparation method includes:
  • lithium salt is finally added for mixing to obtain the electrolyte.
  • the inert atmosphere includes an argon atmosphere.
  • the mixing temperature is 0-5°C, where the temperature can be 0°C, 1°C, 2°C, 3°C, 4°C or 5°C, etc., but is not limited to the listed values. Others not listed within this numerical range The same applies to the values of .
  • the third object of the present application is to provide a lithium-rich manganese-based lithium ion battery, which includes the electrolyte as described in one of the objects.
  • the lithium ion battery also includes a positive electrode piece and a negative electrode piece.
  • the active material of the negative electrode sheet is graphite.
  • the value of 0.5, 0.6, 0.7, 0.8, 0.9 or 1, etc. but are not limited to the listed values, and other unlisted values within the above numerical ranges are also applicable.
  • the lithium-ion battery prepared in this application solves the problem of rapid cycle capacity decay and voltage decay of the ternary lithium-rich manganese-based battery system by adjusting the electrolyte formula.
  • the electrolyte prepared in this application is used in lithium-ion batteries and has a high normal-temperature capacity retention rate.
  • the capacity retention rate can reach more than 80% after 1,000 cycles at 25°C, and the capacity retention rate can reach more than 82% after 500 cycles at 45°C. .
  • the electrolyte includes organic solvents, lithium salts and additives;
  • the mass fraction of the organic solvent in the electrolyte is 83.7%, which is composed of fluorinated ethylene carbonate, ethylene carbonate, diethyl carbonate, and ethyl 2,2,2-trifluoroacetate.
  • the total mass of the organic solvent is 100 In terms of %, fluoroethylene carbonate accounts for 10% of the mass fraction of the organic solvent, ethylene carbonate accounts for 10% of the mass fraction of the organic solvent, diethyl carbonate accounts for 70% of the mass fraction of the organic solvent, 2,2,2-trifluoro Ethyl acetate accounts for 10% of the mass fraction of the organic solvent.
  • the lithium salt is LiPF6, and its mass fraction in the electrolyte is 12.5%.
  • the additives include silicon-based borate functional additives, 1,3-propanesultone, lithium difluorophosphate and vinylene carbonate. Based on the mass fraction of the electrolyte being 100%, the proportion of vinylene carbonate in the electrolyte is The mass fraction of lithium difluorophosphate is 0.5%, the mass fraction of lithium difluorophosphate in the electrolyte is 1.0%, the mass fraction of 1,3-propanesultone in the electrolyte is 2.0%, and the silicon-based borate ester functional additive is shown in Formula 2 compound of The mass fraction in the electrolyte is 0.3%.
  • the electrolyte includes organic solvents, lithium salts and additives;
  • the mass fraction of the organic solvent in the electrolyte is 88.8%, which is composed of propylene carbonate, ethyl methyl carbonate and ethyl difluoroacetate. Based on the total mass of the organic solvent being 100%, propylene carbonate accounts for the mass fraction of the organic solvent. 20%, ethyl methyl carbonate accounts for 70% of the mass fraction of the organic solvent, and ethyl difluoroacetate accounts for 10% of the mass fraction of the organic solvent.
  • the lithium salt is LiFSI, and its mass fraction in the electrolyte is 10%.
  • the additives include silicon-based borate functional additives, 1,3-propanesultone, lithium difluorophosphate and vinylene carbonate. Based on the mass fraction of the electrolyte being 100%, the proportion of vinylene carbonate in the electrolyte is The mass fraction of lithium difluorophosphate is 0.1%, the mass fraction of lithium difluorophosphate in the electrolyte is 0.5%, the mass fraction of 1,3-propanesultone in the electrolyte is 0.5%, and the silicon-based borate ester functional additive is shown in Formula 5 compound of The mass fraction in the electrolyte is 0.1%.
  • the electrolyte includes organic solvents, lithium salts and additives;
  • the mass fraction of the organic solvent in the electrolyte is 80%, consisting of fluoroethylene carbonate, butylene carbonate, (2,2,2-trifluoroethyl) carbonate, and 4,4,4-trifluorobutyric acid.
  • Ethyl ester composition based on the total mass of the organic solvent being 100%, fluoroethylene carbonate accounts for 15% of the mass fraction of the organic solvent, butylene carbonate accounts for 15% of the mass fraction of the organic solvent, (2,2,2-tri Fluoroethyl carbonate accounts for 40% of the mass fraction of the organic solvent, and ethyl 4,4,4-trifluorobutyrate accounts for 30% of the mass fraction of the organic solvent.
  • the lithium salt is LiPF 6 , and its mass fraction in the electrolyte is 15%.
  • the additives include silicon-based borate functional additives, 1,3-propanesultone, lithium difluorophosphate and vinylene carbonate. Based on the mass fraction of the electrolyte being 100%, the proportion of vinylene carbonate in the electrolyte is The mass fraction of lithium difluorophosphate is 1%, the mass fraction of lithium difluorophosphate in the electrolyte is 1%, the mass fraction of 1,3-propanesultone in the electrolyte is 2%, and the silicon-based borate functional additive is shown in Formula 8 compound of The mass fraction in the electrolyte is 1%.
  • Example 1 except that no vinylene carbonate is added and the mass fraction of 1,3-propanesultone in the electrolyte is replaced from 2.0% to 2.5%, other conditions are the same as Example 1.
  • the mass fraction of the silicon-based borate functional additive in the electrolyte is replaced by 1.2%, and the mass fraction of 1,3-propanesultone in the electrolyte is replaced by 2.0% with 1.1%.
  • other conditions are the same as Example 1.
  • the mass fraction of lithium difluorophosphate in the electrolyte is replaced from 1.0% to 1.2%, and the mass fraction of 1,3-propanesultone in the electrolyte is replaced from 2.0% to 1.8%.
  • Other conditions are the same as Example 1.
  • the mass fraction of lithium difluorophosphate in the electrolyte is replaced from 1.0% to 0.3%, and the mass fraction of 1,3-propanesultone in the electrolyte is replaced from 2.0% to 2.7%.
  • Other conditions are the same as Example 1.
  • This embodiment is the same as Example 1 except that 10% ethyl 2,2,2-trifluoroacetate, which accounts for 10% of the organic solvent mass fraction, is replaced by 10% ethylene carbonate.
  • fluorinated ethylene carbonate accounts for 10% of the mass fraction of the organic solvent
  • ethylene carbonate accounts for 10% of the organic solvent
  • diethyl carbonate accounts for 70% of the organic solvent.
  • 2,2,2- Trifluoro The other conditions were the same as Example 1 except that ethyl acetate accounted for 10% of the mass fraction of the organic solvent and was replaced by fluoroethylene carbonate and accounted for 100% of the organic solvent.
  • Example 2 the other conditions are the same as Example 1 except that no silicon-based borate functional additive is added and the mass fraction of 1,3-propanesulactone in the electrolyte is replaced from 2.0% to 2.3%.
  • the specific preparation methods of lithium-ion batteries for testing include:
  • the test method is as follows
  • Capacity retention rate (%) of a lithium-ion battery after N cycles (discharge capacity of the Nth cycle/first discharge capacity) ⁇ 100%, where N is the number of cycles of the lithium-ion battery.
  • Capacity retention rate (%) of a lithium-ion battery after N cycles (discharge capacity of the Nth cycle/first discharge capacity) ⁇ 100%, where N is the number of cycles of the lithium-ion battery.
  • the average voltage (V) of the lithium-ion battery after N cycles the discharge energy of the N-th cycle/the discharge capacity of the N-th cycle, where N is the number of cycles of the lithium-ion battery.
  • Example 4 no vinylene carbonate was added, and the electrochemical performance of the battery decreased compared with Example 1.
  • Example 1 Compared with Example 1 and Example 5, too much silicon-based borate functional additive is added, and the electrochemical performance of the battery is reduced. Comparing Example 1 with Examples 6-7, it can be seen that if too much or too little lithium difluorophosphate is added, the electrochemical performance of the battery will decrease. Comparing Example 1 with Examples 8-9, it can be seen that in the electrolyte of this system, adding too much 1,3-propanesultone will have a negative impact on the normal temperature cycle performance of the battery. Comparing Example 1 and Example 10, it can be seen that if too little 1,3-propanesultone is added, the high-temperature performance of the battery will deteriorate.
  • Example 1 Comparing Example 1 and Examples 11-12, it can be seen that the electrochemical performance of the battery is optimal when the organic solvent in the electrolyte is a combination of cyclic carbonate, chain carbonate and chain carboxylate.
  • Comparing Comparative Example 1 and Example 1 in this application it can be seen that when silicon-based borate functional additives are added to the electrolyte, the normal and high-temperature cycles are significantly improved, which is attributed to the positive electrode film formation and acid removal effects of the functional additives.
  • the positive electrode interface is stabilized, Mn dissolution is inhibited, and the voltage platform decay is slowed down.
  • Comparing Example 1 and Comparative Example 2 it can be seen that Comparative Example 2 does not add silicon-based borate ester functional additives and does not add chain carboxylic acid esters to the organic solvent, so the electrochemical performance of the battery decreases.
  • Chain carboxylic acid esters have good oxidative stability, and the functional additives have the effect of stabilizing the chain carboxylic acid ester system, inhibiting the process of generating HF at high temperatures by the fluorocarboxylic acid esters in Example 1. Therefore, in this application, the ring
  • the electrochemical performance of the battery can be optimized by the synergistic use of organic solvents and additives such as linear carbonate, chain carbonate and chain carboxylate.

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Abstract

The application provides an electrolyte for a lithium-rich manganese-based battery system, a preparation method therefor, and a lithium-rich manganese-based lithium ion battery containing same. The electrolyte comprises an organic solvent, a lithium salt, and an additive. The additive comprises a silicon-based borate functional additive, 1,3-propane sultone, and lithium difluorophosphate. The lithium ion battery prepared in the present application solves the problem of high cycle capacity attenuation and voltage attenuation of the ternary lithium-rich manganese-based battery system by adjusting the formula of the electrolyte.

Description

富锂锰基电池体系电解液及其制备方法和含有其的富锂锰基锂离子电池Lithium-rich manganese-based battery system electrolyte and preparation method thereof, and lithium-rich manganese-based lithium ion battery containing the same
本申请要求在2022年07月27日提交中国专利局、申请号为202210891029.8的中国专利申请的优先权，以上申请的全部内容通过引用结合在本申请中。This application claims priority to the Chinese patent application with application number 202210891029.8, which was submitted to the China Patent Office on July 27, 2022. The entire content of the above application is incorporated into this application by reference.
技术领域Technical field
本申请涉及锂离子电池领域，例如一种富锂锰基电池体系电解液，尤其例如一种富锂锰基电池体系电解液及其制备方法和含有其的富锂锰基锂离子电池。The present application relates to the field of lithium-ion batteries, such as a lithium-rich manganese-based battery system electrolyte, and in particular, a lithium-rich manganese-based battery system electrolyte and its preparation method and a lithium-rich manganese-based lithium ion battery containing the same.
背景技术Background technique
富锂层状氧化物(LLOs)是用于下一代锂离子电池(LIBs)极有前途的高能量密度正极材料。然而，高工作电压导致传统碳酸酯基电解液在LLOs表面严重分解，形成不均匀、不稳定和无保护性的正极-电解液界面(CEI)，阻碍Li+扩散并降低电化学效率。同时，还伴随着晶格氧的释放、过渡金属(尤其是锰)的溶解以及不可逆的结构转变等副反应，严重削弱其电化学性能。富锂锰基正极材料在约2.0-4.8V区间内具有的超过250mAh/g的比容量是其最诱人的性能特点，但是其存在容量衰减、电压衰减较快等突出问题。由于富锂材料热稳定性较差，其高温下晶格氧的释放和过渡金属离子的溶出导致的副反应更为严重。通常，通过对富锂材料表面包覆或表面改性处理的方式，如Li3PO4、V2O5等，减少循环过程0损失和TMs溶出，减弱正极材料与电解液的界面反应，达到抑制富锂材料的容量衰减、电压平台衰减的效果。然而，对材料的包覆难以做到均匀一致，仍然存在一定缺陷，难以很好的阻隔电解液在正极的氧化分解。 Lithium-rich layered oxides (LLOs) are promising high-energy-density cathode materials for next-generation lithium-ion batteries (LIBs). However, high operating voltage causes traditional carbonate-based electrolytes to severely decompose on the surface of LLOs, forming an uneven, unstable and unprotected cathode-electrolyte interface (CEI), hindering Li+ diffusion and reducing electrochemical efficiency. At the same time, it is also accompanied by side reactions such as the release of lattice oxygen, dissolution of transition metals (especially manganese), and irreversible structural transformation, which seriously weakens its electrochemical performance. The lithium-rich manganese-based cathode material has a specific capacity of more than 250mAh/g in the range of about 2.0-4.8V, which is its most attractive performance feature. However, it has outstanding problems such as capacity fading and rapid voltage fading. Due to the poor thermal stability of lithium-rich materials, side reactions caused by the release of lattice oxygen and the dissolution of transition metal ions at high temperatures are more serious. Usually, surface coating or surface modification treatment of lithium-rich materials, such as Li 3 PO 4 , V 2 O 5, etc., is used to reduce zero loss and TMs dissolution during the cycle, weaken the interface reaction between the cathode material and the electrolyte, and achieve The effect of suppressing the capacity fading and voltage platform fading of lithium-rich materials. However, it is difficult to achieve uniform coating of the material, and there are still certain defects, making it difficult to effectively prevent the oxidation and decomposition of the electrolyte in the positive electrode.
CN 113299996A公开了一种三元正极材料与负极硅氧-碳复合负极材料锂离子电池用非水电解液，溶剂由碳酸乙烯酯、碳酸甲乙酯组成，锂盐由六氟磷酸锂、双氟磺酰亚胺锂和二氟草酸硼酸锂组成，添加剂由碳酸亚乙烯酯、氟代碳酸乙烯酯、1，3-丙磺酸内酯、碳酸乙烯亚乙酯和二氟磷酸锂组成，改善电池正负极成膜的稳定性，有效抑制正负极氧化分解与高温产气，提高常高温循环寿命，高温存储性能。但是性能的提升并不能针对适用于富锂锰基体系的电池。CN 113299996A discloses a non-aqueous electrolyte for lithium-ion batteries with a ternary positive electrode material and a negative silicon-oxygen-carbon composite negative electrode material. The solvent is composed of ethylene carbonate and ethyl methyl carbonate, and the lithium salt is composed of lithium hexafluorophosphate and bisfluorosulfonyl. It is composed of lithium amine and lithium difluoroxalate borate. The additives are composed of vinylene carbonate, fluoroethylene carbonate, 1,3-propanesultone, ethylene carbonate and lithium difluorophosphate to improve the positive and negative electrodes of the battery. The stability of the film formation effectively inhibits the oxidative decomposition and high-temperature gas production of the positive and negative electrodes, improves the normal and high-temperature cycle life and high-temperature storage performance. However, the performance improvement cannot be targeted at batteries suitable for lithium-rich manganese-based systems.
CN 110112465 A公开了一种富锂锰基正极材料体系电池用电解液及锂离子电池。添加剂包括氟代碳酸乙烯酯、噻吩-2-甲氧基硼酸频哪醇酯和二(2，2，2，-三氟乙基)碳酸酯。从而降低电池的阻抗，提高电池的高电压高温循环性能。但是对于电池在常温循环性能的提升上没有提高常温性能的优势。CN 110112465 A discloses a lithium-rich manganese-based cathode material system battery electrolyte and lithium-ion battery. Additives include fluoroethylene carbonate, thiophene-2-methoxyboronic acid pinacol ester, and bis(2,2,2,-trifluoroethyl)carbonate. Thereby reducing the impedance of the battery and improving the high voltage and high temperature cycle performance of the battery. However, there is no advantage in improving the normal temperature performance of the battery in terms of improving the normal temperature cycle performance.
因此，如何开发一种可应用于富锂锰基电池体系，明显提升电池常高温性能的电解液，是本领域重要的研究方向。Therefore, how to develop an electrolyte that can be applied to lithium-rich manganese-based battery systems and significantly improve the normal and high-temperature performance of batteries is an important research direction in this field.
发明内容Contents of the invention
以下是对本文详细描述的主题的概述。本概述并非是为了限制权利要求的保护范围。The following is an overview of the topics described in detail in this article. This summary is not intended to limit the scope of the claims.
本申请提供一种富锂锰基电池体系电解液及其制备方法和含有其的富锂锰基锂离子电池。The present application provides a lithium-rich manganese-based battery system electrolyte, a preparation method thereof, and a lithium-rich manganese-based lithium ion battery containing the electrolyte.
本申请采用以下技术方案：This application adopts the following technical solutions:
本申请的目的之一在于提供一种富锂锰基电池体系电解液，所述电解液包括有机溶剂、锂盐和添加剂，所述添加剂包括硅基硼酸酯类功能添加剂、1，3-丙磺酸内酯和二氟磷酸锂。 One of the purposes of this application is to provide a lithium-rich manganese-based battery system electrolyte. The electrolyte includes an organic solvent, a lithium salt and additives. The additives include silicon-based borate functional additives and 1,3-propanesulfonate. Acid lactone and lithium difluorophosphate.
本申请实施例中电解液中硅基硼酸酯类功能添加剂，具有正极成膜和除HF作用，改善了富锂锰基电池体系的循环容量衰减和电压衰减。一方面，电解液添加剂X在正极形成均匀、致密的CEI结构，将LLOs与电解液隔离，避免界面副反应，减少活性氧的释放，阻止TMs从TM层向Li层迁移，以保持脱锂/嵌锂的效率；另一方面，使用上述可去除HF并捕获表面TMs和0功能的成膜添加剂，可以获得更好的CEI协同保护效果。本申请实施例硅基硼酸酯类功能添加剂配合使用1，3-丙磺酸内酯和二氟磷酸锂，1，3-丙磺酸内酯在正、负极辅助成膜，且热稳定性较高，二氟磷酸锂参与正、负极成膜。The silicon-based borate ester functional additives in the electrolyte in the embodiments of the present application have positive electrode film formation and HF removal effects, and improve the cycle capacity attenuation and voltage attenuation of the lithium-rich manganese-based battery system. On the one hand, the electrolyte additive The efficiency of lithium insertion; on the other hand, using the above-mentioned film-forming additives that can remove HF and capture surface TMs and 0 functions can achieve a better CEI synergistic protection effect. In the embodiments of this application, the silicon-based borate functional additive uses 1,3-propanesultone and lithium difluorophosphate. 1,3-propanesultone assists in film formation at the positive and negative electrodes, and has relatively good thermal stability. High, lithium difluorophosphate participates in the film formation of the positive and negative electrodes.
作为本申请实施例可选的技术方案，所述硅基硼酸酯类功能添加剂包括如式1-16中的任意一种或至少两种的组合，其中所述组合典型但非限制性实例有：式1和式2的组合、式2和式3的组合、式3和式4的组合、式5和式6的组合、式7、式8和式9的组合、式10、式11、式12和式13的组合、式14和式2的组合、式15和式3的组合或式16和式1的组合等。

As an optional technical solution for the embodiments of this application, the silicon-based borate functional additives include any one or a combination of at least two of Formulas 1-16, where typical but non-limiting examples of the combination are: The combination of Formula 1 and Formula 2, the combination of Formula 2 and Formula 3, the combination of Formula 3 and Formula 4, the combination of Formula 5 and Formula 6, the combination of Formula 7, Formula 8 and Formula 9, Formula 10, Formula 11, Formula The combination of 12 and Formula 13, the combination of Formula 14 and Formula 2, the combination of Formula 15 and Formula 3, or the combination of Formula 16 and Formula 1, etc.

作为本申请实施例可选的技术方案，所述添加剂还包括碳酸亚乙烯酯。As an optional technical solution in the embodiment of the present application, the additive further includes vinylene carbonate.
本申请实施例中碳酸亚乙烯酯在负极成膜。In the embodiment of this application, vinylene carbonate forms a film on the negative electrode.
在一个实施例中，以所述电解液的质量为100％，按照质量分数计，所述硅基硼酸酯类功能添加剂的质量分数为0.1-1％，其中所述质量分数可以是0.1％、0.2％、0.3％、0.4％、0.5％、0.6％、0.7％、0.8％、0.9％或1％等，但不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用。In one embodiment, assuming that the mass of the electrolyte is 100%, the mass fraction of the silicon-based borate functional additive is 0.1-1% in terms of mass fraction, where the mass fraction can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%, etc., but are not limited to the listed values, and other unlisted values within this range are also applicable.
本申请实施例中硅基硼酸酯类功能添加剂具有成膜和除HF双功能，添加量过少不能在正极形成CEI膜，且起不到较好的除HF效果，添加量过多会带来正 极成膜过厚，阻抗太大导致性能衰减加剧。The silicon-based borate ester functional additives in the embodiments of this application have dual functions of film formation and HF removal. If the added amount is too small, the CEI film cannot be formed on the positive electrode and cannot achieve a good HF removal effect. Too much added amount will cause just The extreme film formation is too thick and the impedance is too large, resulting in increased performance degradation.
在一个实施例中，以所述电解液的质量为100％，按照质量分数计，所述碳酸亚乙烯酯占所述电解液的质量分数为0-1％，其中所述质量分数可以是0、0.1％、0.2％、0.3％、0.4％、0.5％、0.6％、0.7％、0.8％、0.9％或1％等，但不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用。In one embodiment, assuming that the mass of the electrolyte is 100%, in terms of mass fraction, the mass fraction of vinylene carbonate in the electrolyte is 0-1%, where the mass fraction can be 0 , 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%, etc., but are not limited to the listed values, other unlisted values within the range are the same Be applicable.
本申请实施例中碳酸亚乙烯酯在负极成膜，添加量过少不能形成致密的SEI膜，添加量过多会导致阻抗偏大且导致高温产气。In the embodiments of this application, vinylene carbonate forms a film on the negative electrode. If the added amount is too small, a dense SEI film cannot be formed, and if the added amount is too large, the impedance will be too high and the gas will be produced at high temperatures.
在一个实施例中，以所述电解液的质量为100％，按照质量分数计，所述1，3-丙磺酸内酯占所述电解液的质量分数为0.5-3％，其中所述质量分数可以是0.5％、0.8％、1.0％、1.2％、1.4％、1.6％、1.8％、2.0％、2.2％、2.4％、2.6％、2.8％或3％等，但不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用。In one embodiment, assuming that the mass of the electrolyte is 100%, the 1,3-propanesultone accounts for 0.5-3% of the mass fraction of the electrolyte, in terms of mass fraction. The mass fraction may be 0.5%, 0.8%, 1.0%, 1.2%, 1.4%, 1.6%, 1.8%, 2.0%, 2.2%, 2.4%, 2.6%, 2.8% or 3%, etc., but is not limited to those listed Value, other unlisted values within this value range are also applicable.
本申请实施例中1，3-丙磺酸内酯在正、负极辅助成膜，且热稳定性较高，添加量过少不能在负极形成致密的SEI膜，添加量过多会过度成膜阻抗较大，导致循环性能下降。In the embodiments of this application, 1,3-propanesultone assists in film formation on the positive and negative electrodes, and has high thermal stability. If the added amount is too small, a dense SEI film cannot be formed on the negative electrode, and if the added amount is too much, excessive film formation will occur. The impedance is large, resulting in reduced cycle performance.
在一个实施例中，以所述电解液的质量为100％，按照质量分数计，所述二氟磷酸锂占所述电解液的质量分数为0.5-1％，其中所述质量分数可以是0.5％、0.6％、0.7％、0.8％、0.9％或1.0％等，但不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用。In one embodiment, assuming that the mass of the electrolyte is 100%, the mass fraction of the lithium difluorophosphate in the electrolyte is 0.5-1% in terms of mass fraction, where the mass fraction can be 0.5 %, 0.6%, 0.7%, 0.8%, 0.9% or 1.0%, etc., but are not limited to the listed values, and other unlisted values within this numerical range are also applicable.
本申请实施例中二氟磷酸锂参与正、负极成膜，添加量过少不能形成致密的SEI膜，添加量过多不能完全溶解。In the embodiments of this application, lithium difluorophosphate participates in the film formation of the positive and negative electrodes. If the added amount is too small, a dense SEI film cannot be formed, and if the added amount is too large, it cannot be completely dissolved.
在一个实施例中，以所述电解液的质量为100％，按照质量分数计，所述添 加剂占所述电解液的质量分数为1.1-5％，其中所述质量分数可以是1.1％、1.5％、2.0％、2.5％、3％、3.5％、4％、4.5％或5％等，但不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用。In one embodiment, assuming that the mass of the electrolyte is 100%, in terms of mass fraction, the additive The mass fraction of additives in the electrolyte is 1.1-5%, where the mass fraction can be 1.1%, 1.5%, 2.0%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5%, etc. , but not limited to the listed values, other unlisted values within this range are also applicable.
作为本申请实施例可选的技术方案，所述有机溶剂包括环状碳酸酯、链状碳酸酯和链状羧酸酯。As an optional technical solution in the embodiment of the present application, the organic solvent includes cyclic carbonate, chain carbonate and chain carboxylic acid ester.
在一个实施例中，所述环状碳酸酯包括碳酸乙烯酯、碳酸丙烯酯、碳酸丁烯酯或氟代碳酸乙烯酯中的任意一种或至少两种的组合，其中所述组合典型但非限制性实例有：碳酸乙烯酯和碳酸丙烯酯的组合、碳酸丙烯酯和碳酸丁烯酯的组合或碳酸丁烯酯和氟代碳酸乙烯酯的组合等。In one embodiment, the cyclic carbonate includes any one or a combination of at least two of ethylene carbonate, propylene carbonate, butylene carbonate or fluoroethylene carbonate, wherein the combination is typical but not Limiting examples are: a combination of ethylene carbonate and propylene carbonate, a combination of propylene carbonate and butylene carbonate, or a combination of butylene carbonate and fluoroethylene carbonate, and the like.
在一个实施例中，所述链状碳酸酯包括碳酸二甲酯、碳酸二乙酯、碳酸甲乙酯、二(2，2，2-三氟乙基)碳酸酯或甲基三氟乙基碳酸酯中的任意一种或至少两种的组合，其中所述组合典型但非限制性实例有：碳酸二甲酯和碳酸二乙酯的组合、碳酸二乙酯和碳酸甲乙酯的组合、碳酸甲乙酯和二(2，2，2-三氟乙基)碳酸酯的组合或二(2，2，2-三氟乙基)碳酸酯和甲基三氟乙基碳酸酯的组合。In one embodiment, the chain carbonate includes dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, bis(2,2,2-trifluoroethyl) carbonate or methyltrifluoroethyl carbonate. Any one or a combination of at least two carbonates, wherein typical but non-limiting examples of the combination are: the combination of dimethyl carbonate and diethyl carbonate, the combination of diethyl carbonate and ethyl methyl carbonate, A combination of methyl ethyl carbonate and bis(2,2,2-trifluoroethyl) carbonate or a combination of bis(2,2,2-trifluoroethyl) carbonate and methyltrifluoroethyl carbonate.
在一个实施例中，所述链状羧酸酯包括丙酸乙酯、丙酸丙酯、丙酸丁酯、丁酸甲酯、丁酸乙酯、二氟乙酸乙酯、三氟乙酸乙酯、2，2，2-三氟乙酸乙酯、三氟丙酸乙酯或4，4，4-三氟丁酸乙酯中的任意一种或至少两种的组合，其中所述组合典型但非限制性实例有：丙酸乙酯和丙酸丙酯的组合、丙酸丁酯和丁酸甲酯的组合、丁酸乙酯和二氟乙酸乙酯的组合、二氟乙酸乙酯和三氟乙酸乙酯的组合、2，2，2-三氟乙酸乙酯和三氟丙酸乙酯的组合或三氟丙酸乙酯和4，4，4-三氟丁酸乙酯的组合等。In one embodiment, the chain carboxylic acid esters include ethyl propionate, propyl propionate, butyl propionate, methyl butyrate, ethyl butyrate, ethyl difluoroacetate, and ethyl trifluoroacetate. , any one or a combination of at least two of ethyl 2,2,2-trifluoroacetate, ethyl trifluoropropionate or 4,4,4-trifluorobutyrate, wherein the combination is typical but Non-limiting examples are: the combination of ethyl propionate and propyl propionate, the combination of butyl propionate and methyl butyrate, the combination of ethyl butyrate and ethyl difluoroacetate, ethyl difluoroacetate and trifluoroacetate. A combination of ethyl fluoroacetate, a combination of ethyl 2,2,2-trifluoroacetate and ethyl trifluoropropionate, or a combination of ethyl trifluoropropionate and ethyl 4,4,4-trifluorobutyrate, etc. .
作为本申请实施例可选的技术方案，所述环状碳酸酯、链状碳酸酯和链状 羧酸酯的质量比为(20-40)∶(40-70)∶(10-30)，其中所述质量比可以是20∶70∶10、30∶60∶10、40∶50∶10、30∶50∶20、30∶40∶30或40∶40∶20等，但不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用。As optional technical solutions in the embodiments of this application, the cyclic carbonate, chain carbonate and chain carbonate are The mass ratio of carboxylic acid ester is (20-40):(40-70):(10-30), wherein the mass ratio can be 20:70:10, 30:60:10, 40:50:10, 30:50:20, 30:40:30 or 40:40:20, etc., but are not limited to the listed values, and other unlisted values within this range are also applicable.
在一个实施例中，以电解液的质量分数为100％，按照质量分数计，所述有机溶剂占所述电解液的质量分数为80-88.8％，其中所述质量分数可以是80％、81％、82％、86％、84％、85％、86％、87％、88％或88.8％等，但不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用。In one embodiment, assuming that the mass fraction of the electrolyte is 100%, the mass fraction of the organic solvent in the electrolyte is 80-88.8%, where the mass fraction can be 80%, 81 %, 82%, 86%, 84%, 85%, 86%, 87%, 88% or 88.8%, etc., but are not limited to the listed values, and other unlisted values within this numerical range are also applicable.
作为本申请实施例可选的技术方案，所述锂盐包括LiPF6、LiFSI、LiBOB或LiBF4中的任意一种或至少两种的组合，其中所述组合典型但非限制性实例有：LiPF6和LiFSI的组合、LiFSI和LiBOB的组合或LiBOB和LiBF4的组合。As an optional technical solution in the embodiment of the present application, the lithium salt includes any one or a combination of at least two of LiPF 6 , LiFSI, LiBOB or LiBF 4 , where typical but non-limiting examples of the combination are: LiPF 6 combination with LiFSI, LiFSI with LiBOB or LiBOB with LiBF 4 .
在一个实施例中，以电解液的质量分数为100％，按照质量分数计，所述锂盐占所述电解液的质量分数为10-15％，其中所述质量分数可以是10％、11％、12％、13％、14％或15％等，但不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用。In one embodiment, assuming that the mass fraction of the electrolyte is 100%, the mass fraction of the lithium salt in the electrolyte is 10-15%, where the mass fraction can be 10%, 11 %, 12%, 13%, 14% or 15%, etc., but are not limited to the listed values, and other unlisted values within this numerical range are also applicable.
本申请的目的之二在于提供一种如目的之一所述的电解液的制备方法，所述制备方法包括：The second object of the present application is to provide a method for preparing the electrolyte according to the first object. The preparation method includes:
在惰性气氛下，向有机溶剂中加入添加剂后，最后加入锂盐进行混合，得到所述电解液。Under an inert atmosphere, after adding additives to the organic solvent, lithium salt is finally added for mixing to obtain the electrolyte.
作为本申请实施例可选的技术方案，所述惰性气氛包括氩气气氛。As an optional technical solution in the embodiment of the present application, the inert atmosphere includes an argon atmosphere.
在一个实施例中，所述混合的温度为0-5℃，其中所述温度可以是0℃、1℃、2℃、3℃、4℃或5℃等，但不仅限于所列举的数值，该数值范围内其他未列举 的数值同样适用。In one embodiment, the mixing temperature is 0-5°C, where the temperature can be 0°C, 1°C, 2°C, 3°C, 4°C or 5°C, etc., but is not limited to the listed values. Others not listed within this numerical range The same applies to the values of .
本申请的目的之三在于提供一种富锂锰基锂离子电池，所述富锂锰基锂离子电池包括如目的之一所述的电解液。The third object of the present application is to provide a lithium-rich manganese-based lithium ion battery, which includes the electrolyte as described in one of the objects.
所述锂离子电池还包括正极极片和负极极片。The lithium ion battery also includes a positive electrode piece and a negative electrode piece.
作为本申请实施例可选的技术方案，所述负极极片的活性物质为石墨。As an optional technical solution in the embodiment of the present application, the active material of the negative electrode sheet is graphite.
在一个实施例中，所述正极极片的活性物质为mLi2MnO3(1-m)LiMnxNiyCozO2，其中，0.3≤x＜0.5，0.3≤y＜0.5，0＜z≤0.3且x+y+z＝1，0＜m＜1。其中x的值可以是0.3、0.4或0.5等，y的值可以是0.3、0.4或0.5等，z的值可以是0.1、0.2或0.3等，m的值可以是0.1、0.2、0.3、0.4、0.5、0.6、0.7、0.8、0.9或1等，但不仅限于所列举的数值，上述各数值范围内其他未列举的数值同样适用。In one embodiment, the active material of the positive electrode sheet is mLi 2 MnO 3 (1-m)LiMn x Ni y Co z O 2 , where 0.3≤x<0.5, 0.3≤y<0.5, 0<z ≤0.3 and x+y+z=1, 0<m<1. where the value of 0.5, 0.6, 0.7, 0.8, 0.9 or 1, etc., but are not limited to the listed values, and other unlisted values within the above numerical ranges are also applicable.
本申请实施例所述的数值范围不仅包括上述例举的点值，还包括没有例举出的上述数值范围之间的任意的点值，限于篇幅及出于简明的考虑，本申请实施例不再穷尽列举所述范围包括的具体点值。The numerical ranges described in the embodiments of this application not only include the point values exemplified above, but also include any point values between the above numerical ranges that are not exemplified. Due to space limitations and for the sake of simplicity, the embodiments of this application do not The specific point values included in the stated range are then exhaustively enumerated.
本申请的有益效果为：The beneficial effects of this application are:
本申请制备的锂离子电池通过调整电解液配方，解决了三元富锂锰基电池体系循环容量衰减和电压衰减较快的问题。本申请制备的电解液应用于锂离子电池中，具有高的常高温容量保持率，在25℃循环1000次容量保持率可以达到80％以上，45℃循环500次容量保持率可以达到82％以上。The lithium-ion battery prepared in this application solves the problem of rapid cycle capacity decay and voltage decay of the ternary lithium-rich manganese-based battery system by adjusting the electrolyte formula. The electrolyte prepared in this application is used in lithium-ion batteries and has a high normal-temperature capacity retention rate. The capacity retention rate can reach more than 80% after 1,000 cycles at 25°C, and the capacity retention rate can reach more than 82% after 500 cycles at 45°C. .
在阅读并理解了详细描述后，可以明白其他方面。Other aspects will become apparent after reading and understanding the detailed description.
具体实施方式 Detailed ways
下面通过具体实施方式来进一步说明本申请的技术方案。The technical solutions of the present application will be further described below through specific implementations.
实施例1Example 1
本实施例提供一种电解液及其制备方法：This embodiment provides an electrolyte solution and a preparation method thereof:
电解液包括有机溶剂、锂盐和添加剂；The electrolyte includes organic solvents, lithium salts and additives;
有机溶剂在电解液中的质量分数为83.7％，由氟代碳酸乙烯酯、碳酸乙烯酯、碳酸二乙酯、2，2，2-三氟乙酸乙酯组成，以有机溶剂的总质量为100％计，氟代碳酸乙烯酯占有机溶剂的质量分数10％，碳酸乙烯酯占有机溶剂的质量分数10％，碳酸二乙酯占有机溶剂的质量分数70％，2，2，2-三氟乙酸乙酯占有机溶剂的质量分数10％。The mass fraction of the organic solvent in the electrolyte is 83.7%, which is composed of fluorinated ethylene carbonate, ethylene carbonate, diethyl carbonate, and ethyl 2,2,2-trifluoroacetate. The total mass of the organic solvent is 100 In terms of %, fluoroethylene carbonate accounts for 10% of the mass fraction of the organic solvent, ethylene carbonate accounts for 10% of the mass fraction of the organic solvent, diethyl carbonate accounts for 70% of the mass fraction of the organic solvent, 2,2,2-trifluoro Ethyl acetate accounts for 10% of the mass fraction of the organic solvent.
锂盐为LiPF6，其在电解液中的质量分数为12.5％。The lithium salt is LiPF6, and its mass fraction in the electrolyte is 12.5%.
添加剂包括硅基硼酸酯类功能添加剂、1，3-丙磺酸内酯、二氟磷酸锂和碳酸亚乙烯酯，以电解液的质量分数为100％计，碳酸亚乙烯酯在电解液中的质量分数0.5％，二氟磷酸锂在电解液中的质量分数1.0％，1，3-丙磺酸内酯在电解液中的质量分数2.0％，硅基硼酸酯类功能添加剂为式2所示的化合物在电解液中的质量分数0.3％。The additives include silicon-based borate functional additives, 1,3-propanesultone, lithium difluorophosphate and vinylene carbonate. Based on the mass fraction of the electrolyte being 100%, the proportion of vinylene carbonate in the electrolyte is The mass fraction of lithium difluorophosphate is 0.5%, the mass fraction of lithium difluorophosphate in the electrolyte is 1.0%, the mass fraction of 1,3-propanesultone in the electrolyte is 2.0%, and the silicon-based borate ester functional additive is shown in Formula 2 compound of The mass fraction in the electrolyte is 0.3%.
实施例2Example 2
本实施例提供一种电解液及其制备方法：This embodiment provides an electrolyte solution and a preparation method thereof:
电解液包括有机溶剂、锂盐和添加剂； The electrolyte includes organic solvents, lithium salts and additives;
有机溶剂在电解液中的质量分数为88.8％，由碳酸丙烯酯、碳酸甲乙酯和二氟乙酸乙酯组成，以有机溶剂的总质量为100％计，碳酸丙烯酯占有机溶剂的质量分数20％，碳酸甲乙酯占有机溶剂的质量分数70％，二氟乙酸乙酯占有机溶剂的质量分数10％。The mass fraction of the organic solvent in the electrolyte is 88.8%, which is composed of propylene carbonate, ethyl methyl carbonate and ethyl difluoroacetate. Based on the total mass of the organic solvent being 100%, propylene carbonate accounts for the mass fraction of the organic solvent. 20%, ethyl methyl carbonate accounts for 70% of the mass fraction of the organic solvent, and ethyl difluoroacetate accounts for 10% of the mass fraction of the organic solvent.
锂盐为LiFSI，其在电解液中的质量分数为10％。The lithium salt is LiFSI, and its mass fraction in the electrolyte is 10%.
添加剂包括硅基硼酸酯类功能添加剂、1，3-丙磺酸内酯、二氟磷酸锂和碳酸亚乙烯酯，以电解液的质量分数为100％计，碳酸亚乙烯酯在电解液中的质量分数0.1％，二氟磷酸锂在电解液中的质量分数0.5％，1，3-丙磺酸内酯在电解液中的质量分数0.5％，硅基硼酸酯类功能添加剂为式5所示的化合物在电解液中的质量分数0.1％。The additives include silicon-based borate functional additives, 1,3-propanesultone, lithium difluorophosphate and vinylene carbonate. Based on the mass fraction of the electrolyte being 100%, the proportion of vinylene carbonate in the electrolyte is The mass fraction of lithium difluorophosphate is 0.1%, the mass fraction of lithium difluorophosphate in the electrolyte is 0.5%, the mass fraction of 1,3-propanesultone in the electrolyte is 0.5%, and the silicon-based borate ester functional additive is shown in Formula 5 compound of The mass fraction in the electrolyte is 0.1%.
实施例3Example 3
本实施例提供一种电解液及其制备方法：This embodiment provides an electrolyte solution and a preparation method thereof:
电解液包括有机溶剂、锂盐和添加剂；The electrolyte includes organic solvents, lithium salts and additives;
有机溶剂在电解液中的质量分数为80％，由氟代碳酸乙烯酯、碳酸丁烯酯、(2，2，2-三氟乙基)碳酸酯、4，4，4-三氟丁酸乙酯组成，以有机溶剂的总质量为100％计，氟代碳酸乙烯酯占有机溶剂的质量分数15％，碳酸丁烯酯占有机溶剂的质量分数15％，(2，2，2-三氟乙基)碳酸酯占有机溶剂的质量分数40％，4，4，4-三氟丁酸乙酯占有机溶剂的质量分数30％。 The mass fraction of the organic solvent in the electrolyte is 80%, consisting of fluoroethylene carbonate, butylene carbonate, (2,2,2-trifluoroethyl) carbonate, and 4,4,4-trifluorobutyric acid. Ethyl ester composition, based on the total mass of the organic solvent being 100%, fluoroethylene carbonate accounts for 15% of the mass fraction of the organic solvent, butylene carbonate accounts for 15% of the mass fraction of the organic solvent, (2,2,2-tri Fluoroethyl carbonate accounts for 40% of the mass fraction of the organic solvent, and ethyl 4,4,4-trifluorobutyrate accounts for 30% of the mass fraction of the organic solvent.
锂盐为LiPF6，其在电解液中的质量分数为15％。The lithium salt is LiPF 6 , and its mass fraction in the electrolyte is 15%.
添加剂包括硅基硼酸酯类功能添加剂、1，3-丙磺酸内酯、二氟磷酸锂和碳酸亚乙烯酯，以电解液的质量分数为100％计，碳酸亚乙烯酯在电解液中的质量分数1％，二氟磷酸锂在电解液中的质量分数1％，1，3-丙磺酸内酯在电解液中的质量分数2％，硅基硼酸酯类功能添加剂为式8所示的化合物 在电解液中的质量分数1％。The additives include silicon-based borate functional additives, 1,3-propanesultone, lithium difluorophosphate and vinylene carbonate. Based on the mass fraction of the electrolyte being 100%, the proportion of vinylene carbonate in the electrolyte is The mass fraction of lithium difluorophosphate is 1%, the mass fraction of lithium difluorophosphate in the electrolyte is 1%, the mass fraction of 1,3-propanesultone in the electrolyte is 2%, and the silicon-based borate functional additive is shown in Formula 8 compound of The mass fraction in the electrolyte is 1%.
实施例4Example 4
本实施例除不添加碳酸亚乙烯酯，并将1，3-丙磺酸内酯在电解液中的质量分数由2.0％替换为2.5％外，其他条件均与实施例1相同。In this example, except that no vinylene carbonate is added and the mass fraction of 1,3-propanesultone in the electrolyte is replaced from 2.0% to 2.5%, other conditions are the same as Example 1.
实施例5Example 5
本实施例除将硅基硼酸酯类功能添加剂的在电解液中的质量分数替换为1.2％，并将1，3-丙磺酸内酯在电解液中的质量分数2.0％替换为1.1％外，其他条件均与实施例1相同。In this embodiment, the mass fraction of the silicon-based borate functional additive in the electrolyte is replaced by 1.2%, and the mass fraction of 1,3-propanesultone in the electrolyte is replaced by 2.0% with 1.1%. , other conditions are the same as Example 1.
实施例6Example 6
本实施例除将二氟磷酸锂在电解液的质量分数为1.0％替换为1.2％外，并将1，3-丙磺酸内酯在电解液中的质量分数2.0％替换为1.8％外，其他条件均与实施例1相同。In this embodiment, the mass fraction of lithium difluorophosphate in the electrolyte is replaced from 1.0% to 1.2%, and the mass fraction of 1,3-propanesultone in the electrolyte is replaced from 2.0% to 1.8%. Other conditions are the same as Example 1.
实施例7 Example 7
本实施例除将二氟磷酸锂在电解液的质量分数为1.0％替换为0.3％外，并将1，3-丙磺酸内酯在电解液中的质量分数2.0％替换为2.7％外，其他条件均与实施例1相同。In this embodiment, the mass fraction of lithium difluorophosphate in the electrolyte is replaced from 1.0% to 0.3%, and the mass fraction of 1,3-propanesultone in the electrolyte is replaced from 2.0% to 2.7%. Other conditions are the same as Example 1.
实施例8Example 8
本实施例除将1，3-丙磺酸内酯在电解液中的质量分数2.0％替换为3.0％外，并将有机溶剂在电解液中的质量分数替换为82.7％外，其他条件均与实施例1相同。In this example, except that the mass fraction of 1,3-propanesultone in the electrolyte is replaced from 2.0% to 3.0%, and the mass fraction of the organic solvent in the electrolyte is replaced by 82.7%, the other conditions are the same as those in the electrolyte. Same as Example 1.
实施例9Example 9
本实施例除将1，3-丙磺酸内酯在电解液中的质量分数2.0％替换为3.5％外，并将有机溶剂在电解液中的质量分数替换为82.2％外，其他条件均与实施例1相同。In this example, except that the mass fraction of 1,3-propanesultone in the electrolyte is replaced from 2.0% to 3.5%, and the mass fraction of the organic solvent in the electrolyte is replaced by 82.2%, the other conditions are the same as those in the electrolyte. Same as Example 1.
实施例10Example 10
本实施例除将1，3-丙磺酸内酯在电解液中的质量分数2.0％替换为0.2％外，并将有机溶剂在电解液中的质量分数替换为85.5％外，其他条件均与实施例1相同。In this example, except that the mass fraction of 1,3-propanesultone in the electrolyte is replaced from 2.0% to 0.2%, and the mass fraction of the organic solvent in the electrolyte is replaced by 85.5%, the other conditions are the same as those in the electrolyte. Same as Example 1.
实施例11Example 11
本实施例除将占有机溶剂质量分数10％的2，2，2-三氟乙酸乙酯替换为10％碳酸乙烯酯以外，其余与实施例1相同。This embodiment is the same as Example 1 except that 10% ethyl 2,2,2-trifluoroacetate, which accounts for 10% of the organic solvent mass fraction, is replaced by 10% ethylene carbonate.
实施例12Example 12
本实施例除将氟代碳酸乙烯酯占有机溶剂的质量分数10％、碳酸乙烯酯占有机溶剂的质量分数10％、碳酸二乙酯占有机溶剂的质量分数70％、2，2，2-三氟 乙酸乙酯占有机溶剂的质量分数10％，替换为氟代碳酸乙烯酯占有机溶剂的质量分数为100％外，其他条件均与实施例1相同。In this example, fluorinated ethylene carbonate accounts for 10% of the mass fraction of the organic solvent, ethylene carbonate accounts for 10% of the organic solvent, and diethyl carbonate accounts for 70% of the organic solvent. 2,2,2- Trifluoro The other conditions were the same as Example 1 except that ethyl acetate accounted for 10% of the mass fraction of the organic solvent and was replaced by fluoroethylene carbonate and accounted for 100% of the organic solvent.
对比例1Comparative example 1
本对比例除不添加硅基硼酸酯类功能添加剂外，并将1，3-丙磺酸内酯在电解液中的质量分数2.0％替换为2.3％外，其他条件均与实施例1相同。In this comparative example, the other conditions are the same as Example 1 except that no silicon-based borate functional additive is added and the mass fraction of 1,3-propanesulactone in the electrolyte is replaced from 2.0% to 2.3%.
对比例2Comparative example 2
本对比例除不添加剂硅基硼酸酯类功能添加剂，将占有机溶剂质量分数10％的2，2，2-三氟乙酸乙酯替换为10％碳酸乙烯酯外，并将1，3-丙磺酸内酯在电解液中的质量分数2.0％替换为2.3％外，其他条件均与实施例1相同。In this comparative example, there is no silicone borate functional additive, 2,2,2-ethyl trifluoroacetate, which accounts for 10% of the organic solvent mass fraction, is replaced with 10% ethylene carbonate, and 1,3-propane is used. The other conditions were the same as Example 1 except that the mass fraction of sultone in the electrolyte was replaced from 2.0% to 2.3%.
将实施例1-12和对比例1-2中的电解液应用于锂离子电池，用锂离子电池进行性能测试，测试结果如表1所示。The electrolytes in Examples 1-12 and Comparative Examples 1-2 were applied to lithium-ion batteries, and performance tests were performed on the lithium-ion batteries. The test results are shown in Table 1.
其中，测试用的锂离子电池的具体制备方法包括：Among them, the specific preparation methods of lithium-ion batteries for testing include:
将负极材料石墨、导电剂乙炔黑和粘结剂CMC、SBR按质量百分比94∶1∶2∶3制备成浆料涂覆于铜箔集流体上，真空烘干、制得负极极片；将正极材料0.25Li2MnO3·0.75LiMn0.375Ni0.375Co0.25O2、导电剂乙炔黑和粘结剂PVDF按质量比94∶3∶3制备成浆料涂覆于铝箔集流体上，真空烘干、制得正极极片。将正极极片、负极极片、Celgard2400隔膜以及实施例或对比例制备的电解液装配成软包电池，采用新威充放电测试柜进行电化学测试。Prepare the negative electrode material graphite, the conductive agent acetylene black and the binders CMC and SBR according to the mass percentage of 94:1:2:3 to form a slurry and apply it on the copper foil current collector, vacuum drying to prepare the negative electrode sheet; The cathode material 0.25Li 2 MnO 3 ·0.75LiMn 0.375 Ni 0.375 Co 0.25 O 2 , conductive agent acetylene black and binder PVDF are prepared in a mass ratio of 94:3:3 to form a slurry, coated on the aluminum foil current collector, and dried in a vacuum , prepare the positive electrode piece. The positive electrode plate, the negative electrode plate, the Celgard2400 separator and the electrolyte prepared in the examples or comparative examples were assembled into a soft-pack battery, and the Xinwei charge and discharge test cabinet was used for electrochemical testing.
测试实施例1-12和对比例1-2对应的锂离子电池的常高温循序性能，测试方法如下Test the normal and high temperature sequential performance of the lithium-ion batteries corresponding to Examples 1-12 and Comparative Examples 1-2. The test method is as follows
(1)常温循环性能测试： (1)Normal temperature cycle performance test:
在25℃下，将锂离子电池以0.5C(标称容量)恒流充电到电压为4.6V，然后以4.6V恒压充电至电流≤0.05C，搁置10min后，以1C恒流放电至截至电压2.8V，以上为一次充放电循环。将锂离子电池按照上述条件进行25℃下1000次充放电循环。At 25°C, charge the lithium-ion battery at a constant current of 0.5C (nominal capacity) until the voltage is 4.6V, then charge at a constant voltage of 4.6V until the current is ≤0.05C, leave it aside for 10 minutes, and then discharge it at a constant current of 1C until the current reaches 0.05C. The voltage is 2.8V, and the above is one charge and discharge cycle. The lithium-ion battery was subjected to 1000 charge and discharge cycles at 25°C according to the above conditions.
锂离子电池N次循环后的容量保持率(％)＝(第N次循环的放电容量/首次放电容量)×100％，N为锂离子电池的循环次数。Capacity retention rate (%) of a lithium-ion battery after N cycles = (discharge capacity of the Nth cycle/first discharge capacity) × 100%, where N is the number of cycles of the lithium-ion battery.
锂离子电池N次循环后的平均电压(V)＝第N次循环的放电能量/第N次循环的放电容量，N为锂离子电池的循环次数。：The average voltage (V) of the lithium-ion battery after N cycles = the discharge energy of the N-th cycle/the discharge capacity of the N-th cycle, where N is the number of cycles of the lithium-ion battery. :
(2)高温循环性能测试：(2) High temperature cycle performance test:
在45℃下，将锂离子电池以1.0C(标称容量)恒流充电到电压为4.6V，然后以4.6V恒压充电至电流≤0.05C，搁置10min后，以1C恒流放电至截至电压2.8V，以上为一次充放电循环。将锂离子电池按照上述条件进行45℃下500次充放电循环。At 45°C, charge the lithium-ion battery at a constant current of 1.0C (nominal capacity) until the voltage is 4.6V, then charge at a constant voltage of 4.6V until the current is ≤0.05C, leave it aside for 10 minutes, and then discharge it at a constant current of 1C until the current reaches 0.05C. The voltage is 2.8V, and the above is one charge and discharge cycle. The lithium-ion battery was subjected to 500 charge and discharge cycles at 45°C according to the above conditions.
锂离子电池N次循环后的容量保持率(％)＝(第N次循环的放电容量/首次放电容量)×100％，N为锂离子电池的循环次数。Capacity retention rate (%) of a lithium-ion battery after N cycles = (discharge capacity of the Nth cycle/first discharge capacity) × 100%, where N is the number of cycles of the lithium-ion battery.
锂离子电池N次循环后的平均电压(V)＝第N次循环的放电能量/第N次循环的放电容量，N为锂离子电池的循环次数。The average voltage (V) of the lithium-ion battery after N cycles = the discharge energy of the N-th cycle/the discharge capacity of the N-th cycle, where N is the number of cycles of the lithium-ion battery.
表1

Table 1

通过上述表格可以得到，实施例4没有添加碳酸亚乙烯酯，与实施例1相比电池的电化学性能下降，It can be seen from the above table that in Example 4, no vinylene carbonate was added, and the electrochemical performance of the battery decreased compared with Example 1.
实施例1和实施例5相比，硅基硼酸酯类功能添加剂添加过多，电池的电化学性能下降。实施例1和实施例6-7对比可知，二氟磷酸锂添加过多或过少，电池的电化学性能均会下降。实施例1和实施例8-9对比可知，在本体系电解液中，1，3-丙磺酸内酯添加过多，会对电池的常温循环性能产生负面影响。实施例1和实施例10对比可知，1，3-丙磺酸内酯添加过少，电池的高温性能变差。 Compared with Example 1 and Example 5, too much silicon-based borate functional additive is added, and the electrochemical performance of the battery is reduced. Comparing Example 1 with Examples 6-7, it can be seen that if too much or too little lithium difluorophosphate is added, the electrochemical performance of the battery will decrease. Comparing Example 1 with Examples 8-9, it can be seen that in the electrolyte of this system, adding too much 1,3-propanesultone will have a negative impact on the normal temperature cycle performance of the battery. Comparing Example 1 and Example 10, it can be seen that if too little 1,3-propanesultone is added, the high-temperature performance of the battery will deteriorate.
实施例1和实施例11-12对比可知，电解液中有机溶剂为环状碳酸酯、链状碳酸酯和链状羧酸酯的组合时，电池的电化学性能最佳。Comparing Example 1 and Examples 11-12, it can be seen that the electrochemical performance of the battery is optimal when the organic solvent in the electrolyte is a combination of cyclic carbonate, chain carbonate and chain carboxylate.
本申请中对比例1和实施例1对比可知，在电解液中添加硅基硼酸酯类功能添加剂，其常温和高温循环均有显著提高，归因于功能添加剂的正极成膜和除酸作用，稳定了正极界面，抑制了Mn溶出，减缓了电压平台衰减。Comparing Comparative Example 1 and Example 1 in this application, it can be seen that when silicon-based borate functional additives are added to the electrolyte, the normal and high-temperature cycles are significantly improved, which is attributed to the positive electrode film formation and acid removal effects of the functional additives. The positive electrode interface is stabilized, Mn dissolution is inhibited, and the voltage platform decay is slowed down.
实施例1和对比例2对比可知，对比例2不添加硅基硼酸酯类功能添加剂，并且有机溶剂中不添加链状羧酸酯，电池的电化学性能下降。链状羧酸酯具有良好的氧化稳定性，功能添加剂有稳定链状羧酸酯体系的作用，抑制了实施例1中氟代羧酸酯在高温下产生HF的过程，因此，本申请中环状碳酸酯、链状碳酸酯和链状羧酸酯有机溶剂和添加剂的协同配合使用，电池的电化学性能才能达到最佳。 Comparing Example 1 and Comparative Example 2, it can be seen that Comparative Example 2 does not add silicon-based borate ester functional additives and does not add chain carboxylic acid esters to the organic solvent, so the electrochemical performance of the battery decreases. Chain carboxylic acid esters have good oxidative stability, and the functional additives have the effect of stabilizing the chain carboxylic acid ester system, inhibiting the process of generating HF at high temperatures by the fluorocarboxylic acid esters in Example 1. Therefore, in this application, the ring The electrochemical performance of the battery can be optimized by the synergistic use of organic solvents and additives such as linear carbonate, chain carbonate and chain carboxylate.

Claims (10)

  1. 一种富锂锰基电池体系电解液，所述电解液包括有机溶剂、锂盐和添加剂，所述添加剂包括硅基硼酸酯类功能添加剂、1，3-丙磺酸内酯和二氟磷酸锂。A lithium-rich manganese-based battery system electrolyte, the electrolyte includes an organic solvent, a lithium salt and additives, the additives include silicon-based borate functional additives, 1,3-propanesultone and lithium difluorophosphate .
  2. 根据权利要求1所述的电解液，其中，所述硅基硼酸酯类功能添加剂包括如式1-16中的任意一种或至少两种的组合；

    The electrolyte according to claim 1, wherein the silicon-based borate functional additive includes any one or a combination of at least two of Formulas 1-16;

  3. 根据权利要求1或2所述的电解液，其中，所述添加剂还包括碳酸亚乙烯酯；The electrolyte according to claim 1 or 2, wherein the additive further includes vinylene carbonate;
    可选地，以所述电解液的质量为100％，按照质量分数计，所述硅基硼酸酯类功能添加剂的质量分数为0.1-1％；Optionally, assuming that the mass of the electrolyte is 100%, in terms of mass fraction, the mass fraction of the silicon-based borate functional additive is 0.1-1%;
    可选地，以所述电解液的质量为100％，按照质量分数计，所述碳酸亚乙烯酯占所述电解液的质量分数为0-1％；Optionally, assuming that the mass of the electrolyte is 100%, in terms of mass fraction, the mass fraction of vinylene carbonate in the electrolyte is 0-1%;
    可选地，以所述电解液的质量为100％，按照质量分数计，所述1，3-丙磺酸内酯占所述电解液的质量分数为0.5-3％；Optionally, assuming that the mass of the electrolyte is 100%, in terms of mass fraction, the mass fraction of 1,3-propanesultone in the electrolyte is 0.5-3%;
    可选地，以所述电解液的质量为100％，按照质量分数计，所述二氟磷酸锂占所述电解液的质量分数为0.5-1％；Optionally, assuming that the mass of the electrolyte is 100%, the mass fraction of the lithium difluorophosphate in the electrolyte is 0.5-1% in terms of mass fraction;
    可选地，以所述电解液的质量为100％，按照质量分数计，所述添加剂占所述电解液的质量分数为1.1-5％。Optionally, assuming that the mass of the electrolyte is 100%, the mass fraction of the additive in the electrolyte is 1.1-5%.
  4. 根据权利要求1-3任一项所述的电解液，其中，所述有机溶剂包括环状碳酸酯、链状碳酸酯和链状羧酸酯； The electrolyte solution according to any one of claims 1 to 3, wherein the organic solvent includes cyclic carbonate, chain carbonate and chain carboxylate;
    可选地，所述环状碳酸酯包括碳酸乙烯酯、碳酸丙烯酯、碳酸丁烯酯或氟代碳酸乙烯酯中的任意一种或至少两种的组合；Optionally, the cyclic carbonate includes any one or a combination of at least two of ethylene carbonate, propylene carbonate, butylene carbonate or fluoroethylene carbonate;
    可选地，所述链状碳酸酯包括碳酸二甲酯、碳酸二乙酯、碳酸甲乙酯、二(2，2，2-三氟乙基)碳酸酯或甲基三氟乙基碳酸酯中的任意一种或至少两种的组合；Alternatively, the chain carbonate includes dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, bis(2,2,2-trifluoroethyl) carbonate or methyltrifluoroethyl carbonate. Any one or a combination of at least two of them;
    可选地，所述链状羧酸酯包括丙酸乙酯、丙酸丙酯、丙酸丁酯、丁酸甲酯、丁酸乙酯、二氟乙酸乙酯、三氟乙酸乙酯、2，2，2-三氟乙酸乙酯、三氟丙酸乙酯或4，4，4-三氟丁酸乙酯中的任意一种或至少两种的组合。Alternatively, the chain carboxylic acid ester includes ethyl propionate, propyl propionate, butyl propionate, methyl butyrate, ethyl butyrate, ethyl difluoroacetate, ethyl trifluoroacetate, 2 , any one or a combination of at least two of ethyl 2,2-trifluoroacetate, ethyl trifluoropropionate or ethyl 4,4,4-trifluorobutyrate.
  5. 根据权利要求4所述的电解液，其中，所述环状碳酸酯、链状碳酸酯和链状羧酸酯的质量比为(20-40)∶(40-70)∶(10-30)；The electrolyte according to claim 4, wherein the mass ratio of the cyclic carbonate, chain carbonate and chain carboxylate is (20-40): (40-70): (10-30) ;
    可选地，以电解液的质量分数为100％，按照质量分数计，所述有机溶剂占所述电解液的质量分数为80-88.8％。Optionally, assuming that the mass fraction of the electrolyte is 100%, the organic solvent accounts for 80-88.8% of the mass fraction of the electrolyte.
  6. 根据权利要求1-5任一项所述的电解液，其中，所述锂盐包括LiPF6、LiFSI、LiBOB或LiBF4中的任意一种或至少两种的组合；The electrolyte according to any one of claims 1 to 5, wherein the lithium salt includes any one or a combination of at least two of LiPF 6 , LiFSI, LiBOB or LiBF 4 ;
    可选地，以电解液的质量分数为100％，按照质量分数计，所述锂盐占所述电解液的质量分数为10-15％。Optionally, assuming that the mass fraction of the electrolyte is 100%, the lithium salt accounts for 10-15% of the mass fraction of the electrolyte.
  7. 一种如权利要求1-6任一项所述的电解液的制备方法，所述制备方法包括：A method for preparing the electrolyte according to any one of claims 1 to 6, said preparation method comprising:
    在惰性气氛下，向有机溶剂中加入添加剂后，最后加入锂盐进行混合，得到所述电解液。Under an inert atmosphere, after adding additives to the organic solvent, lithium salt is finally added for mixing to obtain the electrolyte.
  8. 根据权利要求7所述的制备方法，其中，所述惰性气氛包括氩气气氛； The preparation method according to claim 7, wherein the inert atmosphere includes an argon atmosphere;
    可选地，所述混合的温度为0-5℃。Optionally, the mixing temperature is 0-5°C.
  9. 一种富锂锰基锂离子电池，所述富锂锰基锂离子电池包括如权利要求1-6任一项所述的电解液；A lithium-rich manganese-based lithium ion battery, the lithium-rich manganese-based lithium ion battery includes the electrolyte as described in any one of claims 1-6;
    所述锂离子电池还包括正极极片和负极极片。The lithium ion battery also includes a positive electrode piece and a negative electrode piece.
  10. 根据权利要求9所述的锂离子电池，其中，所述负极极片的活性物质为石墨；The lithium-ion battery according to claim 9, wherein the active material of the negative electrode sheet is graphite;
    可选地，所述正极极片的活性物质为mLi2MnO3·(1-m)LiMnxNiyCoz02，其中，0.3≤x＜0.5，0.3≤y＜0.5，0＜z≤0.3且x+y+z＝1，0＜m＜1。 Optionally, the active material of the positive electrode sheet is mLi 2 MnO 3 ·(1-m)LiMn x Ni y Co z 0 2 , where 0.3≤x<0.5, 0.3≤y<0.5, 0<z≤ 0.3 and x+y+z=1, 0<m<1.
PCT/CN2023/097340 2022-07-27 2023-05-31 Electrolyte for lithium-rich manganese-based battery system, preparation method therefor, and lithium-rich manganese-based lithium ion battery containing same WO2023213329A1 (en)

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