WO2020119808A1 - Électrolyte, batterie et dispositif - Google Patents

Électrolyte, batterie et dispositif Download PDF

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WO2020119808A1
WO2020119808A1 PCT/CN2019/125328 CN2019125328W WO2020119808A1 WO 2020119808 A1 WO2020119808 A1 WO 2020119808A1 CN 2019125328 W CN2019125328 W CN 2019125328W WO 2020119808 A1 WO2020119808 A1 WO 2020119808A1
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substituted
unsubstituted
formula
electrolyte
additive
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PCT/CN2019/125328
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English (en)
Chinese (zh)
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伊天成
***
钭舒适
蒋耀
梁成都
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宁德时代新能源科技股份有限公司
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Publication of WO2020119808A1 publication Critical patent/WO2020119808A1/fr

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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
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic electrolyte
    • 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

  • This application relates to the field of energy storage materials, in particular, to an electrolyte, battery, and device.
  • Lithium ion batteries are widely used in electric vehicles and consumer electronic products due to their advantages such as high energy density, high output power, long cycle life, and low environmental pollution.
  • the current demand for lithium ion batteries is: high voltage, high power, long cycle life, long storage life and excellent safety performance.
  • Lithium ion batteries are currently widely used electrolyte systems using lithium hexafluorophosphate as a conductive lithium salt and cyclic carbonate and/or chain carbonate as a solvent.
  • lithium hexafluorophosphate as a conductive lithium salt
  • cyclic carbonate and/or chain carbonate as a solvent.
  • the purpose of this application is to provide an electrolyte, a battery and a device, the electrolyte can improve the cycle performance and storage performance of the battery, especially improve the cycle performance and high-voltage cycle performance of the battery Storage performance.
  • the present application provides an electrolytic solution, which contains an organic solvent and an electrolyte salt, and the electrolytic solution further contains additive A and additive B.
  • the additive A is selected from one or more of the compounds represented by Formula I-1, Formula I-2, and Formula I-3.
  • R 1 , R 2 , R 3 , and R 4 are each independently selected from a hydrogen atom, a halogen atom, and a substituted or unsubstituted C 1 to C 12 alkane Group, substituted or unsubstituted C 1 -C 12 alkoxy group, substituted or unsubstituted C 1 -C 12 amine group, substituted or unsubstituted C 2 -C 12 alkenyl group, substituted or unsubstituted C 2 ⁇ C 12 alkynyl, substituted or unsubstituted C 6 to C 26 aryl, substituted or unsubstituted C 2 to C 12 heterocyclic, wherein the substituent is selected from halogen atom, nitrile group, C 1 to C 6 alkane One or more of C 2 to C 6 alkenyl
  • the additive B is selected from one or more of the compounds represented by Formula II-1 and Formula II-2.
  • a, b, c, and d are each independently selected from integers within 1 to 5
  • R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 and R 13 are each independently selected from a substituted or unsubstituted C 1 to C 10 alkylene group, a substituted or unsubstituted C 2 to C 10 alkenylene group, wherein the substituent is selected from a halogen atom and a nitrile
  • the present application provides a battery including the electrolyte described in the first aspect of the present application.
  • the present application provides an apparatus including the battery described in the second aspect of the present application.
  • the present application includes at least the following beneficial effects: the electrolyte of the present application contains a polynitrile six-membered nitrogen heterocyclic compound with a low oxidation potential, which can be formed on the surface of the positive electrode active material when the battery is formed
  • the stable complex layer effectively deactivates the surface of the positive electrode active material, inhibits its oxidation of the electrolyte, and reduces battery gas production;
  • the electrolyte of the present application also contains dinitrile or polynitrile compounds with ether bonds, which It can stably exist in the electrolyte for a long time, and it can repair the complex layer (formed by additive A) that is damaged during cycling or high-temperature storage at any time, reducing the dissolution of transition metal ions, greatly reducing the dissolution of the transition metal and depositing it on the negative electrode to SEI
  • the oxygen (-O-) in the molecular ether group will react with trace amounts of PF 5 and HF in the electrolyte, preventing
  • Corrosion of the surface of the positive electrode active material in the environment makes the surface of the positive electrode active material more durable during cycling and storage; therefore, the electrolyte of the present application can improve the cycle performance and storage performance of the battery, especially the high temperature and high temperature of the battery Cycle performance and storage performance under voltage.
  • the device of the present application includes the aforementioned battery, and therefore has at least the same advantages as the aforementioned battery.
  • Figure 1 shows the NMR carbon spectrum of compound A1.
  • Figure 2 shows the NMR carbon spectrum of the A2 compound.
  • Figure 3 is the NMR carbon spectrum of A3 compound.
  • FIG. 4 is a perspective view of an embodiment of a battery.
  • FIG. 5 is a perspective view of an embodiment of a battery module.
  • FIG. 6 is a perspective view of an embodiment of a battery pack.
  • FIG. 7 is an exploded view of FIG. 6.
  • FIG. 8 is a schematic diagram of an embodiment of a device with a battery as a power source.
  • the electrolytic solution according to the first aspect of the present application contains an organic solvent and an electrolyte salt, and the electrolytic solution further contains additive A and additive B.
  • the additive A is selected from one or more of the compounds represented by Formula I-1, Formula I-2, and Formula I-3.
  • R 1 , R 2 , R 3 , and R 4 are each independently selected from a hydrogen atom, a halogen atom, and a substituted or unsubstituted C 1 to C 12 alkane Group, substituted or unsubstituted C 1 -C 12 alkoxy group, substituted or unsubstituted C 1 -C 12 amine group, substituted or unsubstituted C 2 -C 12 alkenyl group, substituted or unsubstituted C 2 ⁇ C 12 alkynyl group, substituted or unsubstituted C 6 to C 26 aryl group, substituted or unsubstituted C 2 to C 12 heterocyclic group, wherein the substituent (here means substitution in “substituted or unsubstituted or unsubstituted
  • Additive A is a polynitrile six-membered nitrogen heterocyclic compound with a low oxidation potential.
  • the nitrogen atom in the nitrile group contains a lone pair of electrons. It has a strong complexation with the transition metal in the positive electrode active material and is used in the electrolyte. After that, it can be adsorbed on the surface of the positive electrode active material during the formation of the battery to form a loose porous protective film and effectively passivate the surface of the positive electrode active material.
  • the porous protective film not only can isolate the surface of the cathode active material from direct contact with the electrolyte without affecting the normal transmission of ions, but also can reduce the surface activity of the cathode active material while inhibiting a large number of side reactions on the surface of the cathode active material, thereby achieving Reduce the side reaction products and reduce the role of gas production.
  • Additive A has a special six-membered nitrogen heterocyclic structure.
  • the distance between the nitrile group and the nitrile group is closer to the distance between the transition metal and the transition metal on the surface of the positive electrode active material. It can maximize the complexation of the nitrile group and increase the number.
  • the nitrile group has a complexing effect, so compared with the conventional linear nitrile compound, the polynitrile six-membered nitrogen heterocyclic compound of the present application can have a better passivation effect.
  • the special six-membered nitrogen heterocyclic structure of Additive A can also lower the oxidation potential of the molecule, and can form a stable complex layer on the surface of the positive electrode active material when the battery is formed, improving the electrochemical performance of the entire battery system, such as reducing production. Gas, improve the cycle life under high temperature and high voltage, etc.
  • the mass percentage content of the additive A in the electrolyte is 0.1% to 10%. If the content of additive A is too low, the improvement effect on the electrolyte is not obvious; if the content of additive A is too high, the complex layer formed on the surface of the positive electrode active material adsorbed by it is too thick and dense, which affects the diffusion and migration of ions.
  • the positive electrode impedance is greatly increased, and it also causes the overall viscosity of the electrolyte to increase and the ionic conductivity to decrease. Therefore, the excessively high content affects the performance of the battery.
  • the upper limit of the content range of the additive A may be selected from 10%, 9%, 8%, 7%, 6%, 5%, 4.5%, 4%, 3.5%, 3%, 2.5%, 2% , 1.5%, 1%, 0.8%
  • the lower limit of the content range of the additive A can be optionally selected from 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0 %, 1.2%.
  • the mass percentage content of the additive A in the electrolyte is 0.1% to 3.5%.
  • the C 1 -C 12 alkyl group may be a chain alkyl group or a cyclic alkyl group.
  • the chain alkyl group may also be a linear or branched alkyl group.
  • the hydrogen on the ring of the cyclic alkyl group is also It may be further substituted with alkyl.
  • the preferred lower limit of the number of carbon atoms in the C 1 to C 12 alkyl group is 1, 2, 3, 4, and 5, and the preferred upper limit is 3, 4, 5, 6, 8, 10, and 12.
  • C 1 ⁇ C 10 alkyl is selected; further preferably, C 1 ⁇ C 6 chain alkyl, C 3 ⁇ C 8 cyclic alkyl is selected; still more preferably, C 1 ⁇ C 4 chain is selected.
  • Alkyl C 5 -C 7 cyclic alkyl.
  • Examples of the C 1 to C 12 alkyl group specifically include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, Isoamyl, neopentyl, hexyl, 2-methyl-pentyl, 3-methyl-pentyl, 1,1,2-trimethyl-propyl, 3,3-dimethyl-butyl, Heptyl, 2-heptyl, 3-heptyl, 2-methylhexyl, 3-methylhexyl, isoheptyl, octyl, nonyl, decyl.
  • C 1 -C 12 alkyl group contains an oxygen atom
  • it may be a C 1 -C 12 alkoxy group.
  • C 1 -C 10 alkoxy is selected; further preferably, C 1 -C 6 alkoxy is selected; still more preferably, C 1 -C 4 alkoxy is selected.
  • Examples of C 1 to C 12 alkoxy groups include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, t-butoxy, N-pentyloxy, isopentyloxy, cyclopentyloxy, cyclohexyloxy.
  • the C 2 -C 12 alkenyl group may be a cyclic alkenyl group or a chain alkenyl group, and the chain alkenyl group may be a linear alkenyl group or a branched alkenyl group.
  • the number of double bonds in the C 2 to C 12 alkenyl group is preferably one.
  • the preferred lower limit of the number of carbon atoms in the C 2 to C 12 alkenyl group is 2, 3, 4, and 5, and the preferred upper limit is 3, 4, 5, 6, 8, 10, and 12.
  • C 2 -C 10 alkenyl is selected; further preferably, C 2 -C 6 alkenyl is selected; still more preferably, C 2 -C 5 alkenyl is selected.
  • Examples of C 2 to C 12 alkenyl groups include vinyl, allyl, isopropenyl, pentenyl, cyclohexenyl, cycloheptenyl, and cyclooctenyl.
  • the C 2 -C 12 alkynyl group may be a cyclic alkynyl group or a chain alkynyl group, and the chain alkynyl group may be a linear alkynyl group or a branched alkynyl group.
  • the number of triple bonds in the C 2 to C 12 alkynyl group is preferably one.
  • the preferred lower limit of the number of carbon atoms in the C 2 to C 12 alkynyl group is 2, 3, 4, and 5, and the preferred upper limit is 3, 4, 5, 6, 8, 10, and 12.
  • C 2 to C 10 alkynyl is selected; further preferably, C 2 to C 6 alkynyl is selected; still more preferably, C 2 to C 5 alkynyl is selected.
  • Examples of C 2 to C 12 alkynyl groups include ethynyl, propargyl, isopropynyl, pentynyl, cyclohexynyl, cycloheptynyl, and cyclooctynyl groups.
  • the C 1 ⁇ C 12 amino group can be selected from Wherein R ', R "is selected from C 1 ⁇ C 12 alkyl group.
  • C 6 ⁇ C 26 aryl groups can be phenyl, phenalkyl, biphenyl, fused ring aromatic hydrocarbon groups (such as naphthyl, anthracenyl, phenanthrenyl), biphenyl and fused ring aromatic hydrocarbon groups can be further alkyl Or alkenyl substitution.
  • a C 6 -C 16 aryl group is selected; further preferably, a C 6 -C 14 aryl group is selected; still more preferably, a C 6 -C 9 aryl group is selected.
  • Examples of the C 6 -C 26 aryl group include phenyl, benzyl, biphenyl, p-tolyl, o-tolyl, m-tolyl, naphthyl, anthryl, and phenanthryl.
  • the hetero atom in the C 2 -C 12 heterocyclic group may be selected from one or more of oxygen, nitrogen, sulfur, phosphorus, and boron, and the hetero ring may be an aliphatic hetero ring or an aromatic hetero ring.
  • a C 2 -C 10 heterocyclic group is selected; further preferably, a C 2 -C 7 heterocyclic group is selected; still more preferably, a five-membered aromatic heterocyclic ring, a six-membered aromatic heterocyclic ring, and a benzo heterocyclic ring are selected.
  • C 2 to C 12 heterocyclic group specific examples include ethylene oxide, propylene oxide, ethylene sulfide, aziridine, ⁇ -propiolactone, furyl, Thienyl, pyrrolyl, thiazolyl, imidazolyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, indolyl, quinolinyl.
  • the halogen atom as a substituent may be one or more selected from a fluorine atom, a chlorine atom, and a bromine atom, preferably a fluorine atom.
  • the compound represented by Formula I-1 is a polycyanopyrimidine compound.
  • R 1 , R 2 , R 3 , and R 4 are each independently selected from a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, a substituted or unsubstituted C 1 to C 6 linear or branched alkyl group, and a substitution Or unsubstituted C 5 ⁇ C 9 cyclic alkyl, substituted or unsubstituted C 1 ⁇ C 6 alkoxy, substituted or unsubstituted C 1 ⁇ C 6 amino, substituted or unsubstituted C 2 ⁇ C 6 alkenyl, substituted or unsubstituted C 2 -C 6 alkynyl, substituted or unsubstituted C 6 -C 12 aryl, substituted or unsubstituted C 2 -C 12 heterocyclyl; further preferably, R 1 , R 2 , R 3 , and R 4 are each independently selected from a hydrogen atom, a fluorine atom,
  • x is preferably selected from integers of 0 to 6, further preferably selected from integers of 0 to 4, even more preferably selected from 0, 1, or 2.
  • y is preferably selected from integers of 0 to 6, further preferably selected from integers of 0 to 4, even more preferably selected from 0, 1 or 2.
  • n is preferably selected from 1 or 2.
  • R 1 and R 3 are the same group; further preferably, R 1 , R 3 and R 4 are all the same group.
  • R 1 and R 3 are all hydrogen atoms; further preferably, R 1 , R 3 and R 4 are all hydrogen atoms.
  • R 1 , R 2 , R 3 and R 4 are all hydrogen atoms, or R 1 , R 3 and R 4 are all hydrogen atoms and R 2 is selected from fluorine atom, chlorine atom, bromine atom, substituted or unsubstituted C 1 -C 6 linear or branched alkyl, substituted or unsubstituted C 1 -C 6 alkoxy.
  • the substituent is selected from one or more of halogen atoms, preferably, the substituent is selected from fluorine atoms.
  • the compound represented by Formula I-1 may be specifically selected from one or more of the following compounds, but the application is not limited thereto:
  • the compound represented by Formula I-2 is a polynitrile piperazine compound.
  • R 1 , R 2 , R 3 , and R 4 are each independently selected from a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, a substituted or unsubstituted C 1 to C 6 linear or branched alkyl group, and a substitution Or unsubstituted C 5 ⁇ C 9 cyclic alkyl, substituted or unsubstituted C 1 ⁇ C 6 alkoxy, substituted or unsubstituted C 1 ⁇ C 6 amino, substituted or unsubstituted C 2 ⁇ C 6 alkenyl, substituted or unsubstituted C 2 -C 6 alkynyl, substituted or unsubstituted C 6 -C 12 aryl, substituted or unsubstituted C 2 -C 12 heterocyclyl; further preferably, R 1 , R 2 , R 3 , and R 4 are each independently selected from a hydrogen atom, a fluorine atom,
  • x is preferably selected from integers of 0 to 6, further preferably selected from integers of 0 to 4, even more preferably selected from 0, 1, or 2.
  • y is preferably selected from integers of 0 to 6, further preferably selected from integers of 0 to 4, even more preferably selected from 0, 1 or 2.
  • n is preferably selected from 1 or 2.
  • R 1 , R 2 , R 3 , and R 4 are the same group, and further preferably, at least three of R 1 , R 2 , R 3 , and R 4 are the same group.
  • R 1 , R 2 , R 3 , and R 4 are hydrogen atoms; further preferably, at least three of R 1 , R 2 , R 3 , and R 4 are hydrogen atoms.
  • R 1 , R 2 , R 3 and R 4 are all hydrogen atoms, or three of R 1 , R 2 , R 3 and R 4 are hydrogen atoms and the remaining one is selected from fluorine atom, chlorine atom and bromine atom , Substituted or unsubstituted C 1 -C 6 linear or branched alkyl, substituted or unsubstituted C 1 -C 6 alkoxy.
  • the substituent is selected from one or more of halogen atoms, preferably, the substituent is selected from fluorine atoms.
  • the compound represented by Formula I-2 may be specifically selected from one or more of the following compounds, but the application is not limited thereto:
  • the compound represented by Formula I-3 is a polynitrile mesitazine compound.
  • R 1 , R 2 and R 3 are each independently selected from a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, a substituted or unsubstituted C 1 to C 6 linear or branched alkyl group, a substituted or unsubstituted C 5 ⁇ C 9 cyclic alkyl, substituted or unsubstituted C 1 ⁇ C 6 alkoxy, substituted or unsubstituted C 1 ⁇ C 6 amino, substituted or unsubstituted C 2 ⁇ C 6 alkenyl , Substituted or unsubstituted C 2 -C 6 alkynyl, substituted or unsubstituted C 6 -C 12 aryl, substituted or unsubstituted C 2 -C 12 heterocyclyl; further preferably, R 1 , R 2 And R 3 are each independently selected from a hydrogen atom, a fluorine atom, a chlorine atom, a
  • x is preferably selected from integers of 0 to 6, further preferably selected from integers of 0 to 4, even more preferably selected from 0, 1, or 2.
  • y is preferably selected from integers of 0 to 6, further preferably selected from integers of 0 to 4, even more preferably selected from 0, 1 or 2.
  • z is preferably selected from integers of 0 to 6, further preferably selected from integers of 0 to 4, even more preferably selected from 0, 1 or 2.
  • n is preferably selected from 1 or 2.
  • k is preferably selected from 1 or 2.
  • At least two of R 1 , R 2 and R 3 are the same group.
  • At least two of R 1 , R 2 and R 3 are hydrogen atoms.
  • R 1 , R 2 and R 3 are all hydrogen atoms, or two of R 1 , R 2 and R 3 are hydrogen atoms and the remaining one is selected from fluorine atom, chlorine atom, bromine atom, substituted or unsubstituted C 1 -C 6 linear or branched alkyl, substituted or unsubstituted C 1 -C 6 alkoxy.
  • the substituent is selected from one or more of halogen atoms, preferably, the substituent is selected from fluorine atoms.
  • the compound represented by Formula I-3 may be specifically selected from one or more of the following compounds, but the application is not limited thereto:
  • the additive B is selected from one or more of the compounds represented by Formula II-1 and Formula II-2.
  • a, b, c, and d are each independently selected from integers within 1 to 5
  • R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 and R 13 are each independently selected from a substituted or unsubstituted C 1 to C 10 alkylene group, a substituted or unsubstituted C 2 to C 10 alkenylene group, wherein the substituent (here means “substituted or In the case of unsubstituted, substitution occurs) one or more selected from halogen atoms, nitrile groups, C 1 to C 6 alkyl groups, C 2 to C 6 alkenyl groups, and C 1 to C 6 alkoxy groups.
  • Additive B is a dinitrile or polynitrile compound with an ether bond.
  • the nitrogen atom in this molecule contains a lone pair of electrons. It has a strong complexation with the transition metal in the positive electrode active material, and can be repaired at any time or stored at high temperature.
  • the complex layer (formed by additive A) that is destroyed during the process reduces the dissolution of transition metal ions and greatly reduces the damage to the SEI film deposited on the negative electrode after the transition metal dissolves; the oxygen (-O- ) It will also react with trace amounts of PF 5 and HF in the electrolyte to prevent the PF 5 and HF from corroding the surface of the cathode active material that is directly exposed to the electrolyte environment without forming a complex layer, so that the surface of the cathode active material Better durability during cycling and storage. Therefore, when the additive B is applied to the electrolyte, the battery can have better high-temperature and high-pressure cycle performance and storage performance.
  • the mass percentage content of the additive B in the electrolyte is 0.1% to 10%. If the content of additive B is too low, the effect of PF 5 and HF absorption is not obvious, and the surface of the bare positive electrode active material covered by the complex layer will still be corroded; if the content of additive B is too high, the surface of the positive electrode active material will form The complex layer is too thick and dense, and the impedance of the positive and negative electrodes is greatly increased, which affects the performance of the battery.
  • the upper limit of the content range of the additive B can be selected from 10%, 9%, 8%, 7%, 6%, 5%, 4.5%, 4%, 3.5%, 3%, 2.5%, 2% , 1.5%, 1%, 0.8%
  • the lower limit of the content range of the additive B can be optionally selected from 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%.
  • the mass percentage content of the additive B in the electrolyte is 0.1% to 5%.
  • the C 1 -C 10 alkylene group may be a linear alkylene group or a branched chain alkylene group.
  • the preferred lower limit of the number of carbon atoms in the C 1 -C 10 alkylene group is 1, 2, 3, preferably The upper limit of is 4, 5, 6, 7, 8, 9, 10.
  • C 1 to C 6 alkylene is selected; further preferably, C 2 to C 4 alkylene is selected.
  • Examples of C 1 to C 10 alkylene groups include methylene, ethylene, propylene, isopropylene, butylene, isobutylene, sec-butylene, and pentylene. , Akilidene.
  • the C 2 to C 10 alkenylene group may be a straight chain alkenylene group or a branched alkenylene group, and the number of double bonds in the C 2 to C 10 alkenylene group is preferably one.
  • the preferable lower limit of the number of carbon atoms in C 2 to C 12 alkenylene is 2, 3, 4, and 5, and the preferable upper limit is 4, 5, 6, 7, 8, 9, and 10.
  • C 2 to C 6 alkenylene is selected.
  • specific examples of the C 2 to C 10 alkenylene group specific examples include vinylidene group, allylene group, isopropenylene group, allylene group, and alkenylene group.
  • the halogen atom as a substituent may be one or more selected from a fluorine atom, a chlorine atom, and a bromine atom, preferably a fluorine atom.
  • the compound represented by Formula II-1 is a dinitrile compound having an ether bond.
  • a is selected from 1 or 2.
  • R 5 , R 6 , and R 7 are each independently selected from substituted or unsubstituted C 1 -C 6 alkylene, substituted or unsubstituted C 2 -C 6 alkenylene, wherein the substituent is selected from
  • the halogen atom is preferably a fluorine atom. More preferably, R 5 , R 6 , and R 7 are each independently selected from C 1 to C 6 alkylene and C 2 to C 6 alkenylene. Even more preferably, R 5 , R 6 , and R 7 are each independently selected from C 2 to C 4 alkylene.
  • the compound represented by Formula II-1 may be selected from 1,2-bis(cyanoethoxy)ethane, 1,2-bis(cyanopropoxy)ethane, 1,2-bis(cyanobutyl) Oxy)ethane, 1,3-bis(cyanoethoxy)propane, 1,3-bis(cyanopropoxy)propane, 1,3-bis(cyanobutoxy)propane, 1,4-bis (Cyanoethoxy)butane, 1,4-bis(cyanopropoxy)butane, 1,4-bis(cyanobutoxy)butane, 1,5-bis(cyanopropoxy)pentane , 1,6-bis (cyanopropyloxy) hexane in one or more.
  • the compound represented by Formula II-1 may be selected from 1,2-bis(cyanoethoxy)ethane, 1,2-bis(cyanopropoxy)ethane, 1,3-bis(cyano Ethoxy) propane, 1,4-bis(cyanopropoxy)butane, 1,5-bis(cyanopropoxy)pentane, 1,6-bis(cyanopropoxy)hexane Species or several species, the specific structure is as follows:
  • the compound represented by Formula II-2 is a polynitrile compound having an ether bond.
  • b, c, and d are each independently selected from 1 or 2.
  • R 8 , R 9 , R 10 , R 11 , R 12 and R 13 are each independently selected from substituted or unsubstituted C 1 ⁇ C 16 alkylene, substituted or unsubstituted C 2 ⁇ C 6 sub Alkenyl; wherein, the substituent is selected from halogen atoms, preferably fluorine atoms. More preferably, R 8 , R 9 , R 10 , R 11 , R 12 and R 13 are each independently selected from C 1 to C 6 alkylene and C 2 to C 6 alkenylene. Even more preferably, R 8 , R 9 , R 10 , R 11 , R 12 and R 13 are each independently selected from C 2 to C 4 alkylene.
  • the compound represented by Formula II-2 may be selected from 1,2,3-tris(cyanoethoxy)propane, 1,2,3-tris(cyanopropoxy)propane, 1,3,5- Tris(cyanoethoxy)pentane, 1,3,5-tris(cyanopropoxy)pentane, 1,2,6-tris(cyanoethoxy)hexane, 1,4,7-tri( One or more of cyanoethoxy) heptane, the specific structure is as follows:
  • the electrolyte may further contain additive C.
  • the additive C may be selected from cyclic carbonate compounds containing carbon-carbon unsaturated bonds, halogen-substituted cyclic carbonate compounds, sulfate compounds, sultone compounds, disulfonate compounds, sulfite compounds, aromatic compounds , Isocyanate compound, phosphazene compound, acid anhydride compound, phosphite compound, phosphate compound, borate compound one or more.
  • the mass percentage content of the additive C in the electrolyte is 0.01% to 30%.
  • the cyclic carbonate compound containing a carbon-carbon unsaturated bond may be selected from one or more of the compounds represented by Formula III-0.
  • R 20 is selected from C 1 -C 6 alkylene substituted with alkenyl or alkynyl on the branch, substituted or unsubstituted C 2 -C 6 linear alkenylene, wherein The group is selected from one or more of halogen atoms, C 1 to C 6 alkyl groups, and C 2 to C 6 alkenyl groups.
  • the cyclic carbonate compound containing a carbon-carbon unsaturated bond may be specifically selected from one or more of the following compounds, but the application is not limited thereto:
  • the halogen-substituted cyclic carbonate compound may be selected from one or more of the compounds represented by Formula III-1.
  • R 21 is selected from halogen-substituted C 1 -C 6 alkylene and halogen-substituted C 2 -C 6 alkenylene.
  • the halogen-substituted cyclic carbonate compound may be selected from fluoroethylene carbonate (abbreviated as FEC), fluoropropylene carbonate (abbreviated as FPC), trifluoropropylene carbonate (abbreviated as TFPC), trans Or one or more of cis-4,5-difluoro-1,3-dioxolane-2-one (hereinafter both are collectively referred to as "DFEC").
  • FEC fluoroethylene carbonate
  • FPC fluoropropylene carbonate
  • TFPC trifluoropropylene carbonate
  • DFEC trans Or one or more of cis-4,5-difluoro-1,3-dioxolane-2-one (hereinafter both are collectively referred to as "DFEC").
  • the sulfate compound is preferably a cyclic sulfate compound, and the cyclic sulfate compound may be selected from one or more of the compounds represented by Formula III-2.
  • R 22 is selected from substituted or unsubstituted C 1 -C 6 alkylene, substituted or unsubstituted C 2 -C 6 alkenylene, wherein the substituent is selected from halogen atom, C 1 One or more of -C 3 alkyl and C 2 -C 4 alkenyl.
  • R 22 is selected from a substituted or unsubstituted C 1 to C 4 alkylene group, a substituted or unsubstituted C 2 to C 4 alkenylene group, wherein the substituent is selected from a halogen atom , C 1 ⁇ C 3 alkyl, C 2 ⁇ C 4 alkenyl one or more.
  • the sulfate compound may be specifically selected from one or more of the following compounds, but the application is not limited thereto:
  • the sulfate compound is selected from one or more of vinyl sulfate (abbreviated as DTD), propylene sulfate (abbreviated as TMS), 4-methylethylene sulfate (abbreviated as PLS), specific structure as follows:
  • the sultone compound can be selected from one or more of the compounds represented by formula III-3.
  • R 23 is selected from substituted or unsubstituted C 1 -C 6 alkylene, substituted or unsubstituted C 2 -C 6 alkenylene, wherein the substituent is selected from halogen atom, C 1 One or more of -C 3 alkyl and C 2 -C 4 alkenyl.
  • R 23 is selected from substituted or unsubstituted C 1 -C 4 alkylene, substituted or unsubstituted C 2 -C 4 alkenylene, wherein the substituent is selected from halogen atoms , C 1 ⁇ C 3 alkyl, C 2 ⁇ C 4 alkenyl one or more.
  • the sultone compound may be specifically selected from one or more of the following compounds, but the application is not limited thereto:
  • the sultone compound may be selected from one or more of 1,3-propane sultone (abbreviated as PS) and 1,3-propene sultone (abbreviated as PES), specifically
  • PS 1,3-propane sultone
  • PES 1,3-propene sultone
  • R 24 , R 25 , R 26 , and R 27 are each independently selected from a hydrogen atom, a halogen atom, a substituted or unsubstituted C 1 to C 10 alkyl group, and a substituted or unsubstituted C 2 to C 10 alkenyl, wherein the substituent is one or more selected from halogen atoms, C 1 to C 3 alkyl, and C 2 to C 4 alkenyl.
  • R 24 , R 25 , R 26 , and R 27 are each independently selected from a hydrogen atom, a halogen atom, a substituted or unsubstituted C 1 to C 4 alkyl group, a substituted or unsubstituted C 2 -C 6 alkenyl group, wherein the substituent is one or more selected from halogen atom, C 1 -C 3 alkyl group, C 2 -C 4 alkenyl group.
  • the disulfonate compound may be specifically selected from one or more of the following compounds, but the application is not limited thereto:
  • the disulfonate compound may be selected from methylene disulfonate (abbreviated as MMDS), and the specific structure is as follows:
  • the sulfite compound is preferably a cyclic sulfite compound, and specifically can be selected from one or more of the compounds represented by Formula III-5.
  • R 28 is selected from substituted or unsubstituted C 1 -C 6 alkylene, substituted or unsubstituted C 2 -C 6 alkenylene, wherein the substituent is selected from halogen atom, C 1 One or more of -C 3 alkyl and C 2 -C 4 alkenyl.
  • R 28 is selected from substituted or unsubstituted C 1 -C 4 alkylene, substituted or unsubstituted C 2 -C 4 alkenylene, wherein the substituent is selected from halogen atoms , C 1 ⁇ C 3 alkyl, C 2 ⁇ C 4 alkenyl one or more.
  • the sulfite compound may be selected from one or more of vinyl sulfite (abbreviated as ES), propylene sulfite (abbreviated as PS), and butylene sulfite (abbreviated as BS).
  • ES vinyl sulfite
  • PS propylene sulfite
  • BS butylene sulfite
  • the aromatic compound may be selected from cyclohexylbenzene, fluorocyclohexylbenzene compound (1-fluoro-2-cyclohexylbenzene, 1-fluoro-3-cyclohexylbenzene, 1-fluoro-4-cyclohexylbenzene), tert-butyl Benzene, tert-amylbenzene, 1-fluoro-4-tert-butylbenzene, biphenyl, terphenyl (ortho, meta, para), diphenyl ether, fluorobenzene, difluorobenzene (ortho Position, meta position, para position), anisole, 2,4-difluoroanisole, partial hydride of terphenyl (1,2-dicyclohexylbenzene, 2-phenylbicyclohexyl, 1,2 -One or more of diphenylcyclohexane and o-cyclohexylbiphenyl
  • the aromatic compound may be selected from one or more of biphenyl, terphenyl (ortho, meta, para), fluorobenzene, cyclohexylbenzene, t-butylbenzene, t-pentylbenzene Further preferably, the aromatic compound may be selected from one or more of biphenyl, o-terphenyl, fluorobenzene, cyclohexylbenzene, and tert-amylbenzene.
  • the isocyanate compound may be selected from methyl isocyanate, ethyl isocyanate, butyl isocyanate, phenyl isocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, octamethylene diisocyanate, 1,4-phenylene diisocyanate
  • isocyanate 2-isocyanatoethyl acrylate, and 2-isocyanatoethyl methacrylate.
  • the isocyanate compound may be selected from one or more of hexamethylene diisocyanate, octamethylene diisocyanate, 2-isocyanatoethyl acrylate, 2-isocyanatoethyl methacrylate .
  • the phosphazene compound is preferably a cyclic phosphazene compound.
  • the cyclic phosphazene compound can be selected from one of methoxypentafluorocyclotriphosphazene, ethoxypentafluorocyclotriphosphazene, phenoxypentafluorocyclotriphosphazene, and ethoxyheptafluorocyclotetraphosphazenekind or several.
  • the cyclic phosphazene compound may be selected from one or more of methoxypentafluorocyclotriphosphazene, ethoxypentafluorocyclotriphosphazene, and phenoxypentafluorocyclotriphosphazene.
  • the cyclic phosphazene compound may be selected from methoxypentafluorocyclotriphosphazene or ethoxypentafluorocyclotriphosphazene.
  • the acid anhydride compound may be a linear acid anhydride or a cyclic acid anhydride.
  • the acid anhydride compound may be selected from one or more of acetic anhydride, propionic anhydride, succinic anhydride, maleic anhydride, 2-allyl succinic anhydride, glutaric anhydride, itaconic anhydride, 3-sulfo-propionic anhydride Species.
  • the acid anhydride compound may be selected from one or more of succinic anhydride, maleic anhydride, and 2-allyl succinic anhydride. Further preferably, the acid anhydride compound may be selected from one or both of succinic anhydride and 2-allyl succinic anhydride.
  • the phosphite compound may be selected from silane phosphite compounds, and specifically may be selected from one or more of the compounds represented by Formula III-6.
  • R 31 , R 32 , R 33 , R 34 , R 35 , R 36 , R 37 , R 38 , and R 39 are each independently selected from halogen-substituted or unsubstituted C 1 -C 6 alkane base.
  • the silane phosphite compound may be specifically selected from one or more of the following compounds, but the application is not limited thereto:
  • the phosphate compound may be selected from silane phosphate compounds, specifically one or more of the compounds represented by Formula III-7.
  • R 41 , R 42 , R 43 , R 44 , R 45 , R 46 , R 47 , R 48 , and R 49 are each independently selected from halogen-substituted or unsubstituted C 1 to C 6 alkyl base.
  • the silane phosphate compound may be specifically selected from one or more of the following compounds, but the application is not limited thereto:
  • the borate compound may be selected from silane borate compounds, specifically one or more of the compounds represented by Formula III-8.
  • R 51 , R 52 , R 53 , R 54 , R 55 , R 56 , R 57 , R 58 , and R 59 are each independently selected from halogen-substituted or unsubstituted C 1 to C 6 alkane base.
  • the silane borate compound may be specifically selected from one or more of the following compounds, but the application is not limited thereto:
  • the organic solvent used as the electrolyte in the embodiments of the present application is preferably a non-aqueous organic solvent.
  • the organic solvent used in the electrolyte as an embodiment of the present application may include cyclic carbonate and chain carbonate, which can further improve the cycle performance and storage performance under high temperature and high voltage, and it is easy to
  • the electrical conductivity is adjusted to a suitable range, which is more conducive to each additive to achieve a better film-forming effect.
  • the organic solvent used in the electrolyte as an example of the present application may further include a carboxylic acid ester, that is, the organic solvent according to the present application may include a mixture of cyclic carbonate, chain carbonate, and carboxylic acid ester.
  • Carboxylic acid esters have the characteristics of large dielectric constant and low viscosity, which can effectively prevent the association of ions and anions in the electrolyte, and at the same time have more advantages in ion conduction than cyclic carbonates and chain carbonates, especially at low temperatures The following can ensure that the electrolyte has good ion conduction characteristics.
  • the mass percentage content of the cyclic carbonate can be 15% to 55%, preferably 25% to 50%; the mass percentage content of the chain carbonate can be 15% to 74 %, preferably 25% to 70%; the mass percentage content of the carboxylic acid ester may be 0.1% to 70%, preferably 5% to 50%.
  • the cyclic carbonate may be selected from one or more of ethylene carbonate, propylene carbonate, 1,2-butene carbonate, and 2,3-butanediol carbonate. Further preferably, the cyclic carbonate may be one or more selected from ethylene carbonate and propylene carbonate.
  • the chain carbonate may be one or more asymmetric chain carbonates selected from ethyl methyl carbonate, methyl propyl carbonate, methyl isopropyl carbonate, methyl butyl carbonate, and ethyl propyl carbonate.
  • the chain carbonate can also be selected from dimethyl carbonate, diethyl carbonate, dipropyl carbonate, dibutyl carbonate, one or more symmetric chain carbonate; the chain carbonate can also be the above A mixture of asymmetric chain carbonates and symmetric chain carbonates.
  • the carboxylic acid ester may be selected from methyl pivalate, ethyl pivalate, propyl pivalate, butyl pivalate, methyl butyrate, ethyl butyrate, propyl butyrate, butyric acid
  • butyl ester methyl propionate, ethyl propionate, propyl propionate, butyl propionate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate.
  • Li salts-2 suitably selected from (CF 2 ) 2 (SO 2 ) 2 NLi (cyclic), (CF 2 ) 3 (SO 2 ) 2 NLi (cyclic) and LiC (SO one or more of the 2 CF 3) 3 "methyl imide or lithium salts.”
  • [Li salt-5] suitably selected from bis[oxalate-O,O'] lithium borate (LiBOB), difluoro[oxalate-O,O'] lithium borate, difluorobis[oxalic acid Root-O,O']Lithium Phosphate (LiPFO) and tetrafluoro[oxalate-O,O']Lithium Phosphate, one or more "lithium salt with oxalate ligand as positive ion", Among them, it is more preferably selected from LiBOB and LiPFO.
  • the lithium salt can be used alone or in combination.
  • the lithium salt is selected from LiPF 6 , LiPO 2 F 2 , Li 2 PO 3 F, LiBF 4 , LiSO 3 F, trifluoro((methanesulfonyl)oxy) lithium borate (LiTFMSB), bis[oxalic acid One or more of lithium-O,O'] lithium borate (LiBOB), difluorobis[oxalate-O,O'] lithium phosphate (LiPFO) and tetrafluoro[oxalate-O,O'] lithium phosphate Species.
  • the lithium salt is selected from LiPF 6 , LiBF 4 , LiSO 3 F, trifluoro((methanesulfonyl)oxy) lithium borate (LiTFMSB), LiPO 2 F 2 , bis[oxalate-O,O'] One or more of lithium borate (LiBOB) and difluorobis[oxalate-O,O'] lithium phosphate (LiPFO). Even more preferably, the lithium salt is LiPF 6 .
  • the preparation method of the electrolyte is not limited, and can be prepared according to a conventional electrolyte method.
  • the electrolyte of the first aspect of the present application preferably, has a conductivity of 4 mS/cm to 12 mS/cm at 25°C.
  • the additive A can be synthesized by the following method.
  • P20 aqueous solution with a concentration of 30% to 40% is added dropwise to the raw material P-1 within 20min to 60min and quickly stirred. After the completion of the dropwise addition, the solution is rapidly stirred for 15h to 30h, and stirred at 70°C to 90°C in an oil bath under reflux for 3h. 5h, to obtain colorless fuming viscous liquid intermediate product I-1-1; continue to add K 2 CO 3 , KI, anhydrous acetonitrile, quickly stir to form a solid-liquid mixed phase, quickly add raw materials at 40 °C ⁇ 60 °C P-3, continue to stir for 10h-20h, then cool to room temperature, and separate and purify to obtain the compound represented by Formula I-1.
  • the anhydrous sodium carbonate, the raw material P-4 and the raw material P-3 are mixed in absolute ethanol, and the reaction is stirred for 2h to 5h; the hot ethanol is repeatedly washed several times to obtain a crude product, and the compound represented by the formula I-2 is obtained by recrystallization.
  • the anhydrous sodium carbonate, the raw material P-5 and the raw material P-3 are mixed in absolute ethanol, and the reaction is stirred for 2h to 5h; the hot ethanol is repeatedly washed many times to obtain a crude product, and the compound represented by formula I-3 is obtained by recrystallization.
  • the battery according to the second aspect of the present application includes an electrode assembly and the electrolyte according to the first aspect of the present application, the electrode assembly includes a positive pole piece, a negative pole piece, and a separator. It should be noted that the battery according to the second aspect of the present application may be a lithium ion battery, a sodium ion battery, or a magnesium ion battery.
  • the positive pole piece contains a positive electrode active material capable of detaching and intercalating lithium ions
  • the negative pole piece contains a negative electrode active material capable of intercalating and detaching lithium ions
  • the positive electrode active material includes Li x1 Co y1 M 1-y1 O 2-z1 Q z1 , 0.5 ⁇ x1 ⁇ 1.2, 0.8 ⁇ y1 ⁇ 1.0, 0 ⁇ z1 ⁇ 0.1, M is selected From one or more of Al, Ti, Zr, Y, and Mg, Q is selected from one or more of F, Cl, and S.
  • the doping element M acts as a skeleton in the lithium cobalt oxide material, which can reduce cobalt
  • the lattice shape variation during the deep delithiation of the lithium acid material delays the degradation of the bulk structure of the lithium cobaltate material and improves the structural stability of the lithium ion battery when it is used at a high voltage greater than 4.2V.
  • the positive electrode active material may also include lithium nickel oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, the foregoing oxides obtained by adding other transition metals or non-transition metals One or more of the compounds.
  • the negative electrode active material includes soft carbon, hard carbon, artificial graphite, natural graphite, Si, SiO x2 , Si/C composite material, Si alloy, lithium titanate, and can form an alloy with lithium One or more of the metals, 0 ⁇ x2 ⁇ 2.
  • the positive pole piece contains a positive active material that can be extracted and inserted into sodium ions
  • the negative pole piece contains a negative active material that can be inserted and extracted from sodium ions
  • the positive electrode active material may be selected from sodium iron composite oxide (NaFeO 2 ), sodium cobalt composite oxide (NaCoO 2 ), sodium chromium composite oxide (NaCrO 2 ), sodium manganese composite oxide (NaMnO 2 ), sodium Nickel composite oxide (NaNiO 2 ), sodium nickel titanium composite oxide (NaNi 1/2 Ti 1/2 O 2 ), sodium nickel manganese composite oxide (NaNi 1/2 Mn 1/2 O 2 ), sodium iron manganese Composite oxide (Na 2/3 Fe 1/3 Mn 2/3 O 2 ), sodium nickel cobalt manganese composite oxide (NaNi 1/3 Co 1/3 Mn 1/3 O 2 ), sodium iron phosphate compound (NaFePO 4 ), sodium manganese phosphate compound (NaMnPO 4 ), sodium cobalt phosphate compound (NaCoPO 4 ), etc.
  • this application is not limited to these materials, and this application may also use other conventionally known materials that can be used as positive electrode active materials for sodium ion batteries.
  • the negative electrode active material may be selected from hard carbon, natural graphite, artificial graphite, soft carbon, carbon black, acetylene black, carbon nanotubes, graphene, carbon nanofibers, and other carbon materials.
  • examples of other negative electrode active materials include elements such as Si, Ge, Pb, In, Zn, H, Ca, Sr, Ba, Ru, and Rh which are alloyed with sodium, and oxidation containing these elements And carbides.
  • the positive pole piece contains a positive active material that can be extracted and inserted into magnesium ions
  • the negative pole piece contains a negative active material that can be inserted and extracted from magnesium ions.
  • the positive electrode active material may be selected from V 2 O 5 , MoO 3 , MnO 2 , TiS 2 , MoS 2 and the like
  • the negative electrode active material may be selected from metal magnesium, magnesium alloy, graphite and the like.
  • the separator is provided between the positive pole piece and the negative pole piece to play a role of isolation.
  • the specific type of the separator is not specifically limited, and may be any separator material used in existing batteries, such as polyethylene, polypropylene, polyvinylidene fluoride, and their multilayer composite films, but not limited to these .
  • the positive pole piece further includes a binder and a conductive agent.
  • the positive electrode slurry containing the positive electrode active material, the binder and the conductive agent is coated on the positive electrode current collector, and the positive electrode sheet is obtained after the positive electrode slurry is dried.
  • the types and contents of conductive agent and binder are not specifically limited, and can be selected according to actual needs.
  • the type of positive electrode current collector is also not subject to specific restrictions, and can be selected according to actual needs.
  • the negative pole piece further includes a binder and a conductive agent.
  • the negative electrode slurry containing the negative electrode active material, the binder and the conductive agent is coated on the negative electrode current collector, and the negative electrode sheet is obtained after the negative electrode slurry is dried.
  • the types and contents of conductive agent and binder are not specifically limited, and can be selected according to actual needs.
  • the type of negative electrode current collector is not subject to specific restrictions, and can be selected according to actual needs.
  • the charge cut-off voltage of the battery may be not less than 4.2V, that is, the battery may be used in a high voltage state not less than 4.2V.
  • the higher the valence state of the transition metal on the surface of the positive electrode active material the stronger the Coulomb interaction with the nitrile group in the additive A, that is, the greater the degree of additive A's corresponding protection.
  • the battery can operate in the range of 4.2V to 4.9V, and further preferably, the battery can operate in the range of 4.3V to 4.8V.
  • the battery of the second aspect of the present application may include an outer package for encapsulating the positive pole piece, the negative pole piece and the electrolyte.
  • the positive electrode sheet, the negative electrode sheet, and the separator may be laminated or wound to form a laminated structure electrode assembly or a wound structure electrode assembly.
  • the electrode assembly is packaged in an outer package; the electrolyte is infiltrated into the electrode assembly.
  • the number of electrode assemblies in the battery can be one or several, which can be adjusted according to requirements.
  • the battery of the second aspect of the present application may be either a hard case outer package or a flexible package. It is preferable to use a metal hard shell (for example, aluminum shell, steel shell, etc.) for the hard shell outer packaging.
  • the flexible packaging preferably uses a packaging bag as the battery outer packaging.
  • the packaging bag generally includes an accommodating portion and a sealing portion, wherein the accommodating portion is used to accommodate the electrode assembly and the electrolyte, and the sealing portion is used to seal the electrode assembly and the electrolyte.
  • the electrolyte described in the first aspect of the present application improves the performance of the flexible package battery more obviously, because the flexible package battery is prone to swell when in use, and this application can greatly reduce the gas production of the battery and avoid the shortening of the life of the flexible package battery.
  • FIG. 4 is a battery 5 of a square structure as an example.
  • the battery may be assembled into a battery module, and the number of batteries contained in the battery module may be multiple, and the specific number may be adjusted according to the application and capacity of the battery module.
  • FIG. 5 is a battery module 4 as an example.
  • a plurality of batteries 5 may be arranged in sequence along the length direction of the battery module 4. Of course, it can also be arranged in any other way. Further, the plurality of batteries 5 can be fixed by fasteners.
  • the battery module 4 may further include a housing having an accommodating space, and a plurality of batteries 5 are accommodated in the accommodating space.
  • the above battery modules can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be adjusted according to the application and capacity of the battery pack.
  • the battery pack 1 may include a battery box and a plurality of battery modules 4 provided in the battery box.
  • the battery case includes an upper case 2 and a lower case 3.
  • the upper case 2 can be covered on the lower case 3 and forms an enclosed space for accommodating the battery module 4.
  • the plurality of battery modules 4 can be arranged in the battery box in any manner.
  • an apparatus in a third aspect of the present application, includes the battery of the second aspect of the present application, and the battery provides power for the apparatus.
  • the device may be, but not limited to, mobile equipment (such as mobile phones, notebook computers, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf balls) Vehicles, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.
  • the device can select a battery, battery module or battery pack according to its usage requirements.
  • FIG. 8 is a device as an example.
  • the device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle.
  • a battery pack or battery module may be used.
  • the device may be a mobile phone, a tablet computer, a notebook computer, or the like.
  • the device is usually required to be thin and light, and a battery can be used as a power source.
  • batteries were prepared according to the following methods.
  • a mixed solution of ethylene carbonate (abbreviated as EC), ethyl methyl carbonate (abbreviated as EMC) and diethyl carbonate (abbreviated as DEC) is used as an organic solvent, wherein the mass ratio of EC, EMC and DEC is 1:1 :1.
  • the lithium salt is LiPF 6 , and the content of LiPF 6 is 12.5% of the total mass of the electrolyte.
  • Each additive is added according to the electrolyte composition shown in Table 1, wherein the content of each additive component is calculated relative to the total mass of the electrolyte.
  • additives A and B used in the examples and comparative examples are abbreviated as:
  • the positive electrode active material shown in Table 1, the binder PVDF, and the conductive agent acetylene black were mixed according to a mass ratio of 98:1:1, N-methylpyrrolidone was added, and stirred under the action of a vacuum mixer until stable and uniform, to obtain a positive electrode slurry ; Evenly coat the positive electrode slurry on the aluminum foil; dry the aluminum foil at room temperature and transfer to a 120°C blast oven to dry for 1h, and then cold press and cut to obtain the positive pole piece.
  • the lithium ion battery is first charged with a constant current of 1C to a voltage of 4.35V, further charged with a constant voltage of 4.35V to a current of 0.05C, and then discharged with a constant current of 1C to a voltage of 3.0V, which is a charge
  • the current discharge capacity is the first cycle discharge capacity.
  • the lithium-ion battery was subjected to 200 cycles of charge/discharge test according to the above method, and the discharge capacity at the 200th cycle was detected.
  • Capacity retention rate (%) after 200 cycles of the lithium ion battery (discharge capacity of the lithium ion battery after 200 cycles/discharge capacity of the first cycle of the lithium ion battery) ⁇ 100%.
  • the lithium ion battery is first charged with a constant current of 1C to a voltage of 4.35V, further charged with a constant voltage of 4.35V to a current of 0.05C, and then discharged with a constant current of 1C to a voltage of 3.0V, which is a charge
  • the current discharge capacity is the first cycle discharge capacity.
  • the lithium-ion battery was subjected to 200 cycles of charge/discharge test according to the above method, and the discharge capacity at the 200th cycle was detected.
  • Capacity retention rate (%) after 200 cycles of the lithium ion battery (discharge capacity of the lithium ion battery after 200 cycles/discharge capacity of the first cycle of the lithium ion battery) ⁇ 100%.
  • Lithium-ion battery thickness expansion rate (%) after storage at 85°C for 24 hours [(h 1 -h 0 )/h 0 ] ⁇ 100%.
  • the electrolyte of the present application contains the combined additive of additive A and additive B.
  • the additive A is a polynitrile six-membered nitrogen heterocyclic compound with a low oxidation potential, which can form a stable complex layer on the surface of the positive electrode active material when the battery is formed, effectively passivating the surface of the positive electrode active material and reducing the positive electrode
  • the surface activity of the active material isolates the direct contact between the electrolyte and the surface of the positive electrode active material, which greatly reduces the surface side reactions, and the lithium ions consumed in the side reactions are correspondingly reduced, that is, the consumption rate of reversible lithium ions is greatly reduced, and finally appears
  • the actual effect is that the lithium-ion battery cycle capacity retention rate has been greatly improved; some surface side reactions can produce gas, and the reduction of surface side reactions also means that the battery gas production is reduced.
  • Additive B is a dinitrile or polynitrile compound with an ether bond, which can stably exist in the electrolyte for a long time, and can repair the complex layer (formed by additive A) that is damaged during cycling or high-temperature storage at any time, reducing
  • the dissolution of transition metal ions greatly reduces the damage of the SEI film deposited on the negative electrode after the transition metal dissolution; the oxygen (-O-) in this type of molecular ether group will react with trace amounts of PF 5 and HF in the electrolyte to prevent PF 5.
  • the electrolyte of the present application can significantly improve the cycle performance and storage performance of the lithium ion battery under high temperature and high voltage.
  • the polynitrile six-membered nitrogen heterocyclic compound of the present application has a special six-membered nitrogen heterocyclic structure, and the distance between the nitrile group and the nitrile group is closer to the surface of the positive electrode active material The distance between the transition metal and the transition metal can maximize the complexation of the nitrile group, and allow a greater number of nitrile groups to exert the complexation.
  • the polynitrile six-membered nitrogen heterocyclic compound of the present application has a stronger covering effect on the transition metal on the surface of the positive electrode active material, has a better passivation effect on the surface of the positive electrode active material, and improves the cycle performance and storage performance of the lithium ion battery The effect is also more outstanding.
  • the examples of the present application also use metal ion M-doped lithium cobaltate material Li x1 Co y1 M 1-y1 O 2-z1 Q z1 as the positive electrode active material, doped Element M serves as a skeleton in the positive electrode active material, which can reduce the lattice deformation of the positive electrode active material during the deep delithiation process, delay the degradation of the bulk structure of the positive electrode active material, and greatly improve the lithium ion battery when used at high voltage Structural stability.
  • additive A When the addition amount of additive A is large, first, the complex layer formed by additive A adsorbed on the surface of the positive electrode active material is easy to be thicker and denser, which affects the diffusion and migration of lithium ions, and the impedance of the positive electrode is greatly increased; secondly, additive A is formed At the same time, the complex layer will consume lithium ions, resulting in the reduction of lithium ions that can be used for recycling. Finally, the higher amount of additive A will cause the overall viscosity of the electrolyte to increase and the ion conductivity to decrease. Finally, the lithium ion battery is at 25 °C and 45 The cycle capacity retention rate at °C showed a downward trend after reaching the best. Therefore, an appropriate amount of the additive A needs to be added, preferably 0.1% to 10.0%, and more preferably 0.1% to 3.5%.
  • an appropriate amount of the additive B needs to be added, and the addition is 0.1% to 10.0%, and more preferably 0.1% to 5.0%.

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Abstract

L'invention concerne un électrolyte, une batterie (5) et un dispositif. L'électrolyte contient un solvant organique et un sel d'électrolyte. L'électrolyte contient également un additif A et un additif B. L'additif A est un composé hétérocyclique azoté polycano à six chaînons ayant un potentiel d'oxydation inférieur, et l'additif B est un composé dinitrile ou polynitrile ayant une liaison éther. L'électrolyte peut améliorer les performances de cycle et les performances de stockage de la batterie (5), et améliore notamment les performances de cycle et les performances de stockage lorsque la batterie (5) est soumise à des températures élevées et à des tensions élevées.
PCT/CN2019/125328 2018-12-14 2019-12-13 Électrolyte, batterie et dispositif WO2020119808A1 (fr)

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