WO2022042374A1 - 锂离子电池非水电解液以及锂离子电池 - Google Patents

锂离子电池非水电解液以及锂离子电池 Download PDF

Info

Publication number
WO2022042374A1
WO2022042374A1 PCT/CN2021/113013 CN2021113013W WO2022042374A1 WO 2022042374 A1 WO2022042374 A1 WO 2022042374A1 CN 2021113013 W CN2021113013 W CN 2021113013W WO 2022042374 A1 WO2022042374 A1 WO 2022042374A1
Authority
WO
WIPO (PCT)
Prior art keywords
lithium ion
carbonate
aqueous electrolyte
ion battery
formula
Prior art date
Application number
PCT/CN2021/113013
Other languages
English (en)
French (fr)
Inventor
钱韫娴
胡时光
褚艳丽
康媛媛
Original Assignee
深圳新宙邦科技股份有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 深圳新宙邦科技股份有限公司 filed Critical 深圳新宙邦科技股份有限公司
Publication of WO2022042374A1 publication Critical patent/WO2022042374A1/zh

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—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
    • 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
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—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

  • the present invention relates to the technical field of lithium ion battery electrolyte, in particular to a lithium ion battery non-aqueous electrolyte and a lithium ion battery.
  • lithium-ion batteries Due to a series of advantages such as high operating voltage, high safety, long life, and no memory effect, lithium-ion batteries have made great progress in the field of portable electronic products. With the development of new energy vehicles, lithium-ion batteries have great application prospects in power supply systems for new energy vehicles.
  • electrolyte plays a crucial role in improving the energy density and cycle stability of lithium-ion batteries.
  • a series of reactions occur between the electrolyte and the electrode material to form a solid electrolyte interface film (SEI film) covering the surface of the electrode material. ).
  • SEI film solid electrolyte interface film
  • the unstable SEI film will lead to the continuous consumption and continuous reaction of the electrolyte, resulting in a series of irreversible by-products, resulting in an increase in the internal resistance of the battery, volume expansion, and even fire or explosion in severe cases, which is harmful to the safety of the battery. Sex poses great dangers. Therefore, the stability of the SEI film can determine the performance of Li-ion batteries.
  • Optimizing the composition of the electrolyte is an important method to improve the stability of the SEI film of lithium-ion batteries. Compared with organic solvents and lithium salts, the additive demand is small, the effect is significant, and the cost is low. Therefore, many researchers choose to use different film-forming additives (such as vinylene carbonate, fluoroethylene carbonate, ethylene ethylene carbonate) to improve the performance of the battery. D. Aurbach et al. studied the additive vinylene carbonate (VC) by electrochemical and spectroscopic methods, and found that VC can improve the cycle performance of the battery, especially the cycle performance at high temperature, and reduce the irreversible capacity.
  • VC additive vinylene carbonate
  • VC can polymerize on the graphite surface to form a polyalkyl lithium carbonate film, thereby inhibiting the reduction of solvent and salt anions.
  • GHWrodnigg et al. added 5 vol% ethylene sulfite (ES) or propylene sulfite (PS) to 1 mol/L LiClO 4 /PC, which can effectively prevent PC molecules from intercalating into the graphite electrode, and at the same time improve the electrolyte's performance. low temperature performance.
  • the reason may be that the reduction potential of ES is about 2V (vs. Li/Li + ), which can be reduced in preference to the solvent and form an SEI film on the surface of the graphite anode.
  • the purpose of the present invention is to overcome the problem of poor performance of lithium ion batteries in the prior art at high temperatures, and to provide a lithium ion battery non-aqueous electrolyte and a lithium ion battery prepared by using the electrolyte.
  • the battery can simultaneously improve the high-temperature storage and high-temperature cycle performance of the battery.
  • a first aspect of the present invention provides a non-aqueous electrolyte for a lithium ion battery
  • the non-aqueous electrolyte solution contains an organic solvent, a lithium salt, and a compound represented by the following formula (1) and/or formula (2):
  • R 1 -R 6 are each independently selected from hydrogen, alkyl or haloalkyl of 1-6 carbon atoms, ether group or haloether of 1-8 carbon atoms group, unsaturated hydrocarbon group of 2-6 carbon atoms or ester group of 1-6 carbon atoms.
  • the alkyl group of 1-6 carbon atoms is selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, neobutyl or tert-butyl.
  • the haloalkyl group of 1-6 carbon atoms is selected from the haloalkyl group of 1-6 carbon atoms in which at least one hydrogen in the alkyl group is replaced by a halogen element; more preferably, the halogen element is fluorine.
  • the unsaturated hydrocarbon group of 2-6 carbon atoms is selected from vinyl, propenyl, allyl, propynyl, propargyl, methylvinyl or methallyl.
  • the compound represented by the formula (1) is selected from one or more compounds having the following structures:
  • the compound represented by the formula (2) is selected from one or more compounds having the following structures:
  • the content of the compound represented by the formula (1) is 10 ppm or more of the total weight of the non-aqueous electrolyte of the lithium ion battery; more preferably, the content of the compound represented by the formula (1) is the lithium ion 10ppm-3% by weight of the total weight of the battery non-aqueous electrolyte.
  • the content of the compound represented by the formula (2) is 10 ppm-1 wt % of the total weight of the non-aqueous electrolyte of the lithium ion battery; more preferably, the content of the compound represented by the formula (2) is 10ppm-0.8% by weight of the total weight of the non-aqueous electrolyte of the lithium ion battery.
  • the organic solvent is a mixture of cyclic carbonate and chain carbonate.
  • the cyclic carbonate is selected from one or more of ethylene carbonate, propylene carbonate, butylene carbonate and butylene carbonate.
  • the chain carbonate is selected from one or more of dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate and propyl methyl carbonate.
  • the lithium salt is selected from LiPF 6 , LiBF 4 , LiPO 2 F 2 , LiTFSI, LiBOB, LiDFOB, LiTFSI, LiSbF 6 , LiAsF 6 , LiN(SO 2 CF 3 ) 2 , LiC(SO 2 CF 3 ) 3 and one or more of LiN( SO2F)2 .
  • the content of the lithium salt in the non-aqueous electrolyte of the lithium ion battery is 0.5-3 mol/L; more preferably, the content of the lithium salt in the non-aqueous electrolyte of the lithium ion battery is 0.7-1.5 mol/L.
  • the lithium salt is selected from LiPF 6 and/or LiPO 2 F 2 .
  • the non-aqueous electrolyte further comprises additives selected from one or more of unsaturated cyclic carbonates, fluorinated cyclic carbonates, cyclic sultones and cyclic sulfates .
  • the unsaturated cyclic carbonate is selected from one or more of vinylene carbonate, ethylene ethylene carbonate and methylene ethylene carbonate.
  • the fluorocyclic carbonate is selected from one or more of fluoroethylene carbonate, trifluoromethyl ethylene carbonate and difluoroethylene carbonate.
  • the cyclic sultone is selected from one or more of 1,3-propane sultone, 1,4-butane sultone and propenyl-1,3-sultone .
  • the cyclic sulfate is selected from vinyl sulfate, vinyl 4-methyl sulfate and one or more of.
  • the additive is vinylene carbonate, fluoroethylene carbonate, 1,3-propane sultone, and one or more of vinyl sulfate.
  • the content of the additive is 0.1-5 wt % of the total weight of the non-aqueous electrolyte of the lithium ion battery.
  • a second aspect of the present invention provides a lithium ion battery, the lithium ion battery comprising a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and the non-aqueous electrolyte for the lithium ion battery described in the first aspect of the present invention.
  • the active material of the positive electrode of the lithium ion battery is selected from LiNi x Co y M z L (1-xyz) O 2 , LiCo x' L (1-x') O 2 , LiNi x" L' y' M (2-x"-y') O 4 and one or more of Li z' MPO 4 ,
  • L is one or more of Al, Sr, Mg, Ti, Ca, Zr, Zn, Si and Fe;
  • L' is one or more of Co, Al, Sr, Mg, Ti, Ca, Zr, Zn, Si and Fe;
  • M is one or more of Fe, Al, Mn and Co;
  • the lithium ion battery non-aqueous electrolyte of the present invention when used and the lithium ion battery is further prepared, the capacity retention rate of the lithium ion battery during storage and use at high temperature can be significantly improved, and the thickness of the battery during storage can be effectively reduced. expansion rate.
  • a first aspect of the present invention provides a non-aqueous electrolyte for a lithium ion battery, the non-aqueous electrolyte comprising an organic solvent, a lithium salt, and a compound represented by the following formula (1) and/or formula (2):
  • R 1 -R 6 are each independently selected from hydrogen, alkyl or haloalkyl of 1-6 carbon atoms, ether group or haloether of 1-8 carbon atoms group, unsaturated hydrocarbon group of 2-6 carbon atoms or ester group of 1-6 carbon atoms.
  • the alkyl group of 1-6 carbon atoms is selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, neobutyl or tert-butyl.
  • the haloalkyl group of 1-6 carbon atoms is selected from the haloalkyl group of 1-6 carbon atoms in which at least one hydrogen in the alkyl group is replaced by a halogen element; more preferably, the halogen element is fluorine.
  • the unsaturated hydrocarbon group of 2-6 carbon atoms is selected from vinyl, propenyl, allyl, propynyl, propargyl, methylvinyl or methallyl.
  • the compound represented by the formula (1) is selected from one or more compounds having the following structures:
  • the compound represented by the formula (1) is selected from one or more compounds having the following structures:
  • the compound represented by the formula (1) can be synthesized according to the following method:
  • the compound represented by the formula (A) is reacted with the compound represented by the formula (B-1) and/or the formula (B-2) at -10°C to 20°C to obtain the formula ( 1) The compound represented.
  • R 1 -R 4 can be independently selected from hydrogen, alkyl or haloalkyl with 1-6 carbon atoms, ether group or halogen with 1-8 carbon atoms Substituted ether group, unsaturated hydrocarbon group of 2-6 carbon atoms or ester group of 1-6 carbon atoms.
  • the acid binding agent can be a conventional choice in the field, such as N,N-diisopropylethylamine (DIEA), pyridine and triethylamine, etc.
  • DIEA N,N-diisopropylethylamine
  • pyridine pyridine
  • triethylamine a conventional choice in the field
  • the acid binding agent The agent is triethylamine.
  • the target compound can be obtained by a conventional treatment method in the art, for example, the target compound can be obtained by a method such as column chromatography.
  • the compound represented by the formula (2) can be synthesized according to the following method: first, the compound represented by the following formula (C) is reacted with thionyl chloride at 30-60° C. to obtain the compound represented by the formula (D) compound; then, the compound represented by formula (D) is reacted with the compound represented by formula (E) under the condition of 0-60° C. to obtain the compound represented by formula (F); finally, the compound represented by formula (F) is placed in In the presence of ruthenium trichloride, the compound represented by formula (2) can be obtained after catalytic reaction with an oxidant at -10-50°C.
  • R 5 -R 6 can be independently selected from hydrogen, alkyl or haloalkyl of 1-6 carbon atoms, ether or halogenated ether of 1-8 carbon atoms, Unsaturated hydrocarbon group or ester group of 1-6 carbon atoms.
  • the oxidant can be a conventional choice in the art, preferably, the oxidant is one or more of sodium periodate, sodium hypochlorite and calcium hypochlorite.
  • the inventors of the present invention have found through intensive research that when the non-aqueous electrolyte of the lithium ion battery contains the compound represented by the formula (1) and/or the formula (2), the high temperature cycling and storage of the lithium ion battery Performance will be significantly improved. This may be because during the first charging process, the compound represented by the formula (1) or (2) can react on the electrode surface to form a passivation film, thereby inhibiting further decomposition of solvent molecules. In addition, the passivation film formed by it is resistant to high temperature and will not be damaged during high temperature cycling and storage, and the compound represented by the formula (1) or formula (2) can also repair the passivation film damaged due to high temperature. The other components in the battery can ensure the stability of the battery interface film at high temperature, and improve the high temperature cycle and high temperature storage performance of the battery.
  • the content of the compound represented by the formula (1) when used to prepare a non-aqueous electrolyte, may be 10 ppm or more of the total weight of the non-aqueous electrolyte of the lithium ion battery; preferably, the formula (1) The content of the indicated compound is 10 ppm to 3 wt % of the total weight of the non-aqueous electrolyte for the lithium ion battery.
  • the content of the compound represented by the formula (2) may be 10 ppm-1 wt % of the total weight of the non-aqueous electrolyte of the lithium ion battery; preferably, the content of the compound represented by the formula (2) is the lithium ion 10ppm-0.8% by weight of the total weight of the battery non-aqueous electrolyte.
  • the storage and cycle performance of the lithium ion battery at high temperature can be effectively improved.
  • the content of the compound represented by the formula (1) and/or the formula (2) is lower than this range, although there is a certain improvement effect, the effect is not obvious; when the formula (1) and/or the formula (2)
  • the storage and cycle performance of the lithium ion battery at high temperature will be adversely affected, which may be due to the higher content of the compound represented by formula (1) and/or formula (2) after adding , which increases the viscosity of the electrolyte, which further leads to an increase in the overall impedance of the battery, thereby reducing the storage and cycling performance at high temperatures.
  • the organic solvent in the non-aqueous electrolyte of the lithium ion battery can be various organic solvents commonly used in the field to prepare non-aqueous electrolytes, and is not particularly limited.
  • One or more of carbonates, carboxylates, ethers, and the like are used as the organic solvent.
  • the organic solvent is a mixture of cyclic carbonate and chain carbonate, when the organic solvent is selected from the mixture of cyclic carbonate and chain carbonate, the non-aqueous electrolyte can be Obtain higher dielectric constant and lower viscosity.
  • the cyclic carbonate is selected from one or more of ethylene carbonate, propylene carbonate and butylene carbonate;
  • the chain carbonate is selected from dimethyl carbonate, diethyl carbonate, One or more of methyl ethyl carbonate and methyl propyl carbonate.
  • the organic solvent is a mixture of ethylene carbonate (EC), diethyl carbonate (DEC) and ethyl methyl carbonate (EMC), and the content ratio of the three is 1:1:1, by using the above three compounds in the above ratio range as the organic solvent, the non-aqueous electrolyte can obtain higher conductivity, which is beneficial to improve the overall performance of the battery.
  • EC ethylene carbonate
  • DEC diethyl carbonate
  • EMC ethyl methyl carbonate
  • the lithium salt in the non-aqueous electrolyte of the lithium ion battery can use various lithium salts commonly used in the preparation of lithium ion batteries in the art, without special limitation, for example, LiPF 6 , LiPO 2 F 2 , LiBF can be selected 4.
  • LiPF 6 LiPO 2 F 2
  • LiBF can be selected 4.
  • LiBOB LiClO 4 , LiCF 3 SO 3 , LiDFOB, LiN(SO 2 CF 3 ) 2 , LiN(SO 2 F) 2 , LiTFSI, LiDFOB, and the like.
  • the lithium salt is selected from one or more of LiPF 6 , LiBF 4 , LiPO 2 F 2 , LiTFSI, LiBOB, LiDFOB and LiN(SO 2 F) 2 . More preferably, the lithium salt is selected from LiPF 6 and/or LiPO 2 F 2 .
  • the electrical conductivity of the non-aqueous electrolyte can be significantly improved, the performance of the lithium ion battery can be improved, and the production cost can be reduced.
  • the content of the lithium salt may be the usual content in lithium ion batteries in the art, and is not particularly limited.
  • the content of the lithium salt in the non-aqueous electrolyte of the lithium ion battery is 0.5-3 mol/L; preferably, the content of the lithium salt in the non-aqueous electrolyte of the lithium ion battery is 0.7-1.5 mol/L.
  • the content of the lithium salt is within this range, it can ensure that the electrical conductivity of the non-aqueous electrolyte is high and the overall performance of the battery is excellent.
  • the non-aqueous electrolyte of the lithium ion battery may further contain various additives commonly used in the art to improve the performance of lithium ion batteries,
  • additives for example, unsaturated cyclic carbonates, fluorinated cyclic carbonates, cyclic sultones, cyclic sulfates, and the like can be selected.
  • the unsaturated cyclic carbonate is selected from vinylene carbonate (CAS: 872-36-6), vinyl ethylene carbonate (CAS: 4427-96-7) and methylene carbonate One or more of vinyl esters (CAS: 124222-05-5).
  • the fluorinated cyclic carbonate is selected from fluoroethylene carbonate (CAS: 114435-02-8), trifluoromethyl ethylene carbonate (CAS: 167951-80-6), and difluoroethylene carbonate (CAS: 167951-80-6).
  • fluoroethylene carbonate CAS: 311810-76-1
  • the cyclic sultone is selected from 1,3-propane sultone (CAS: 1120-71-4), 1,4-butane sultone (CAS: 1633-83) -6) and one or more of propenyl-1,3-sultone (CAS: 21806-61-1).
  • the cyclic sulfate is selected from vinyl sulfate (CAS: 1072-53-3), 4-methyl vinyl sulfate (CAS: 5689-83-8) and one or more of.
  • the additives are vinylene carbonate (VC), fluoroethylene carbonate (FEC), 1,3-propane sultone (PS), and one or more of vinyl sulfate (DTD).
  • VC vinylene carbonate
  • FEC fluoroethylene carbonate
  • PS 1,3-propane sultone
  • DTD vinyl sulfate
  • the inventors of the present invention found that when the above-mentioned additives are further added to the lithium ion battery, they can play a synergistic effect with the compounds represented by formula (1) and/or formula (2), thereby further improving the comprehensive performance of the lithium ion battery.
  • a second lithium salt can be further added as an additive to improve the performance of the lithium ion battery.
  • a second lithium salt LiN(SO 2 F) 2 is added.
  • LiN(SO 2 F) 2 As an additive, by adding LiN(SO 2 F) 2 as an additive, the capacity retention rate and the capacity recovery rate of the lithium ion battery can be further improved.
  • the content of the additive can be the conventional content of various additives in the lithium ion battery in the art.
  • the content of the additive may be 0.1-5 wt % of the total weight of the non-aqueous electrolyte of the lithium ion battery; preferably, the content of the additive may be 0.1 of the total weight of the non-aqueous electrolyte of the lithium ion battery -3 wt%; more preferably, the content of the additive may be 0.5-1 wt% of the total weight of the non-aqueous electrolyte of the lithium ion battery.
  • a second aspect of the present invention provides a lithium ion battery comprising a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and the non-aqueous electrolyte for the lithium ion battery described in the first aspect of the present invention.
  • the active material of the positive electrode of the lithium ion battery can be selected from LiNi x Co y M z L (1-xyz) O 2 , LiCo x' L (1-x') O 2 , LiNi x" L' y One or more of ' M (2-x"-y') O 4 and Li z' MPO 4 , wherein L is one of Al, Sr, Mg, Ti, Ca, Zr, Zn, Si and Fe One or more; L' is one or more of Co, Al, Sr, Mg, Ti, Ca, Zr, Zn, Si and Fe; M is one or more of Fe, Al, Mn and Co Various; and 0 ⁇ x ⁇ 1, 0 ⁇ y ⁇ 1, 0 ⁇ z ⁇ 1, 0 ⁇ x+y+z ⁇ 1, 0 ⁇ x' ⁇ 1, 0.3 ⁇ x" ⁇ 0.6, 0.01 ⁇ y' ⁇ 0.2, 0.5 ⁇ z' ⁇ 1.
  • the active material of the positive electrode of the lithium ion battery can be represented by LiNi x Co y M z L (1-xyz) O 2 , where x can be 0.5, y can be 0.2, z can be 0.3, and M can be Mn, that is, the active material of the positive electrode of the lithium ion battery thus represented is LiNi 0.5 Co 0.2 Mn 0.3 O 2 .
  • the active material of the negative electrode can be selected from various materials commonly used in the negative electrode active material of lithium ion batteries in the art, without special limitation, for example, it can be metal lithium, graphite-like carbon material, hard carbon material, soft One or more of carbon materials, silicon-based, tin-based, antimony-based, aluminum-based, and transition metal compounds; in the present invention, preferably, the active material of the negative electrode is artificial graphite, natural graphite and silicon carbon. one or more.
  • the preparation of the positive electrode and the negative electrode of the lithium ion battery can be carried out according to the method commonly used in the art for preparing the positive electrode and the negative electrode of the lithium ion battery, and there is no particular limitation.
  • the active materials of the positive and negative electrodes can be mixed with a conductive agent and a binder, and the mixture can be dispersed in an organic solvent to prepare a slurry, and then the obtained slurry can be coated on a current collector and dried and rolled, etc. deal with.
  • the conductive agent, adhesive, organic solvent, current collector, etc. used can all be materials and substances commonly used in the art, which will not be repeated here.
  • the separator placed between the positive electrode and the negative electrode can be various materials commonly used as separators in the field, without particular limitation, for example, can be polyolefin separators, polyamide separators, polysulfone separators , one or more of polyphosphazene diaphragms, polyethersulfone diaphragms, polyetheretherketone diaphragms, polyetheramide diaphragms and polyacrylonitrile diaphragms; preferably, the diaphragms are selected from polyolefins Diaphragm and/or polyacrylonitrile type diaphragm.
  • the preparation of the lithium ion battery can be carried out by the "sandwich" method commonly used in the art.
  • a separator is placed between the positive plate and the negative plate coated with the active material, and then the whole is wound, Then, the coiled body is flattened and placed in a packaging bag to be vacuum-baked and dried to obtain a battery cell. Then, the electrolyte is injected into the battery core, vacuum-sealed and left to stand for formation.
  • This method is a conventional method in the art and will not be repeated here.
  • the compound represented by the formula (D-1) is reacted with the compound represented by the formula (E-1) at 0-60°C to obtain the compound represented by the formula (F-1); after that, the compound represented by the formula ( Compound 2 can be obtained after the compound shown in F-1) is catalyzed by ruthenium trichloride under the condition of -10-50°C with oxidants such as sodium periodate, sodium hypochlorite, calcium hypochlorite, etc.
  • Test Example 1 High temperature cycle performance test
  • the lithium-ion batteries prepared in the following examples and comparative examples were placed in an oven with a constant temperature of 45°C, and charged to 4.4V (LiNi 0.5 Co 0.2 Mn 0.3 O 2 /artificial graphite battery) or 4.2V (LiNi 0.5 Co 0.2 Mn 0.3 O 2 /artificial graphite battery) at a constant current of 1C.
  • the capacity retention rate for high temperature cycling is calculated as follows:
  • Capacity retention rate 300th discharge capacity/1st discharge capacity ⁇ 100%.
  • the lithium-ion batteries prepared in the following examples and comparative examples were charged to 4.4V (LiNi 0.5 Co 0.2 Mn 0.3 O 2 /artificial graphite battery) or 4.2V (LiNi 0.8 Co 0.15 Al 0.05 O) with 1C constant current and constant voltage at room temperature 2 /artificial graphite battery) or 4.48V (LiCoO2/artificial graphite battery) or 3.65V ( LiFePO4 /artificial graphite battery), measure the initial discharge capacity and initial battery thickness of the battery, and then store it at 60 °C for 30 days.
  • 4.4V LiNi 0.5 Co 0.2 Mn 0.3 O 2 /artificial graphite battery
  • 4.2V LiNi 0.8 Co 0.15 Al 0.05 O
  • LiFePO4 /artificial graphite battery LiFePO4 /artificial graphite battery
  • Battery capacity retention rate (%) retained capacity / initial capacity ⁇ 100%;
  • Thickness expansion ratio (%) (battery thickness after storage ⁇ initial battery thickness)/initial battery thickness ⁇ 100%.
  • the positive active material lithium nickel cobalt manganese oxide LiNi 0.5 Co 0.2 Mn 0.3 O 2 , the conductive agent conductive carbon black Super-P and the binder polyvinylidene fluoride (PVDF) are uniformly mixed in a weight ratio of 93:4:3 , and then disperse the obtained mixture in N-methyl-2-pyrrolidone (NMP) to obtain a positive electrode slurry; evenly coat the positive electrode slurry on both sides of the aluminum foil, dry, calender and vacuum dry, and use ultrasonic welding
  • NMP N-methyl-2-pyrrolidone
  • the negative active material artificial graphite, the conductive agent conductive carbon black Super-P, and the binder styrene-butadiene rubber (SBR) and carboxymethyl cellulose (CMC) are mixed uniformly according to the weight ratio of 94:1:2.5:2.5, and then Disperse the mixture in deionized water to obtain a negative electrode slurry; coat the negative electrode slurry on both sides of the copper foil, dry, calender and vacuum dry, and weld the nickel lead wires with an ultrasonic welder to obtain a negative electrode plate,
  • the thickness of the plates is 120-150 ⁇ m.
  • a three-layer separator with a thickness of 20 ⁇ m is placed between the positive plate and the negative plate, and then the sandwich structure composed of the positive plate, the negative plate and the separator is wound, and then the rolled body is flattened and placed in an aluminum foil packaging bag. Vacuum bake at 75°C for 48h to obtain the cell to be injected.
  • the electrolyte prepared in step 1) was injected into the battery cell prepared in step 4), and it was vacuum-sealed and left to stand for 24 hours;
  • routine formation of the first charging is carried out according to the following steps: 0.05C constant current charging for 180min, 0.2C constant current charging to 3.95V, secondary vacuum sealing, and then further charging with 0.2C current constant current to 4.4V, and shelving at room temperature for 24hrs After that, discharge to 3.0V with a constant current of 0.2C.
  • the difference is that the type and content of the compound represented by the formula (1) or formula (2) and other additives added to the positive electrode active material of the lithium ion battery, the non-aqueous electrolyte, and the other additives are different. shown in Table 1.
  • LiNi 0.8 Co 0.15 Al 0.05 O 2 /artificial graphite battery 0.05C constant current charging for 180min, 0.1C constant current charging for 180min, 0.2C constant current charging for 120min, and two It was sealed under vacuum, and then charged to 4.2V with a constant current and constant voltage of 0.2C, and the cut-off current was 0.05C. After leaving it at room temperature for 5 minutes, it was discharged to 3V with a constant current of 0.2C.
  • LiCoO 2 /artificial graphite battery formed by hot pressing, charged with 0.1C constant current for 45min, upper limit voltage 3.8V, pressure 8Kg/CC, charged with 0.2C constant current for 30min, upper limit voltage 4.4V, pressure 8Kg/CC, constant current at 0.5C Current charging for 75min, the upper limit voltage is 4.4V, the pressure is 8Kg/CC, the secondary vacuum sealing is carried out, and then it is further charged to 4.48V with a current constant current and voltage of 0.2C, and the cut-off current is 0.03C. Discharge to 3V.
  • LiFePO 4 /artificial graphite battery formed by hot pressing, charged with 0.03C constant current for 120min, upper limit voltage 3.65V, pressure 3Kg/CC, charged with 0.1C constant current for 60min, upper limit voltage 3.65V, pressure 3Kg/CC, constant current at 0.2C Current charging for 60min, upper limit voltage 3.65V, pressure 6Kg/CC, secondary vacuum sealing, and then further charging to 3.65V with 0.2C current constant current and constant voltage, cut-off current 0.05C, after 5min at room temperature, 0.2C constant current Discharge to 2.5V.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Inorganic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Secondary Cells (AREA)

Abstract

本发明涉及锂离子电池电解液技术领域，公开了一种锂离子电池非水电解液以及由此制备的锂离子电池。采用本发明提供的锂离子电池非水电解液进一步制备锂离子电池时，可以同时提高电池的高温存储及高温循环性能，有效降低电池在存储中的厚度膨胀率。

Description

锂离子电池非水电解液以及锂离子电池 技术领域
本发明涉及锂离子电池电解液技术领域，具体涉及一种锂离子电池非水电解液以及锂离子电池。
背景技术
因工作电压高、安全性高、寿命长、无记忆效应等一系列优点，锂离子电池在便携式电子产品领域中取得了长足的发展。随着新能源汽车的发展，锂离子电池在新能源汽车用动力电源系统中具有巨大的应用前景。
作为锂离子电池的血液，电解液对于提升锂离子电池的能量密度和循环稳定性等起着至关重要的作用。在锂离子电池的充放电过程中，伴随着Li +可逆地嵌入/脱嵌反应，电解液与电极材料会发生一系列的反应，形成一层覆盖于电极材料表面的固态电解质界面膜(SEI膜)。作为电子绝缘体和锂离子导体，稳定的SEI膜可以阻止电解液与电极材料的进一步接触，对锂离子电池的电化学性能和安全性能具有巨大的影响。反之，不稳定的SEI膜则会导致电解液的持续消耗与不断反应，生成一系列的不可逆的副产物，造成电池内阻增加、体积膨胀，严重时甚至会引发火灾或爆炸，对电池的安全性造成极大的隐患。因此，SEI膜的稳定性可以决定锂离子电池性能的好坏。
优化电解液的组成是提高锂离子电池的SEI膜稳定性的重要方法，相对于有机溶剂及锂盐而言，添加剂需求量少，效果显著，且成本较低，因此许多科研工作者选择使用不同的成膜添加剂(如碳酸亚乙烯酯，氟代碳酸乙烯酯，碳酸乙烯亚乙酯)来改善电池的各项性能。D.Aurbach等用电化学方法和谱学方法研究添加剂碳酸亚乙烯酯(VC)，发现VC能够提高电池的循环性能，尤其是可以提高电池在高温时的循环性能，并降低不可逆容量。其主要原因是VC可以在石墨表面发生聚合，生成聚烷基碳酸锂膜，从而抑制溶剂和盐阴离子的还原。G.H.Wrodnigg等在1mol/L的LiClO 4/PC中添加5体积％的亚硫酸乙烯酯(ES)或亚硫酸丙烯酯(PS)，可以有效地防止PC分子嵌入石墨电极，同时还可提高电解液的低温性能。其原因可能是ES的还原电位约为2V(vs.Li/Li +)，能够优先于溶剂还原，并在石墨负极表面形成SEI膜。
虽然上述研究对电池性能的改善起到了十分重要的作用，但是到目前为止，这方面的研究工作还不够成熟，例如关于提高锂离子电池工作温度范围的添加剂的报道不多，尤其是应用于提高锂离子电池高温性能方面的添加剂种类十分有限。
发明内容
本发明的目的是为了克服现有技术存在的锂离子电池在高温下性能不良的问题，提供一种锂离子电池非水电解液和采用该电解液制备的锂离子电池，采用该电解液制备的电池可以同时提高电池的高温存储及高温循环性能。
为了实现上述目的，本发明第一方面提供一种锂离子电池非水电解液，
所述非水电解液包含有机溶剂、锂盐以及由以下式(1)和/或式(2)表示的化合物：
Figure PCTCN2021113013-appb-000001
在式(1)和式(2)中，R 1-R 6各自独立地选自氢、1-6个碳原子的烷基或卤代烷基、1-8个碳原子的醚基或卤代醚基、2-6个碳原子的不饱和烃基或1-6个碳原子的酯基。
优选地，所述1-6个碳原子的烷基选自甲基、乙基、丙基、异丙基、丁基、异丁基、新丁基或叔丁基。
优选地，所述1-6个碳原子的卤代烷基选自烷基中至少一个氢被卤素元素取代的1-6个碳原子的卤代烷基；更优选地，所述卤素元素为氟。
优选地，所述2-6个碳原子的不饱和烃基选自乙烯基、丙烯基、烯丙基、丙炔基、炔丙基、甲基乙烯基或甲基烯丙基。
优选地，所述式(1)表示的化合物选自具有以下结构的化合物中的一种或多种：
Figure PCTCN2021113013-appb-000002
优选地，所述式(2)表示的化合物选自具有以下结构的化合物中的一种或多种：
Figure PCTCN2021113013-appb-000003
Figure PCTCN2021113013-appb-000004
优选地，所述式(1)表示的化合物的含量为所述锂离子电池非水电解液总重量的10ppm以上；更优选地，所述式(1)表示的化合物的含量为所述锂离子电池非水电解液总重量的10ppm-3重量％。
优选地，所述式(2)表示的化合物的含量为所述锂离子电池非水电解液总重量的10ppm-1重量％；更优选地，所述式(2)表示的化合物的含量为所述锂离子电池非水电解液总重量的10ppm-0.8重量％。
优选地，所述有机溶剂为环状碳酸酯和链状碳酸酯的混合物。
优选地，所述环状碳酸酯选自碳酸乙烯酯、碳酸丙烯酯、碳酸丁烯酯和碳酸丁烯酯中的一种或多种。
优选地，所述链状碳酸酯选自碳酸二甲酯、碳酸二乙酯、碳酸甲乙酯和碳酸甲丙酯中的一种或多种。
优选地，所述锂盐选自LiPF 6、LiBF 4、LiPO 2F 2、LiTFSI、LiBOB、LiDFOB、LiTFSI、LiSbF 6、LiAsF 6、LiN(SO 2CF 3) 2、LiC(SO 2CF 3) 3和LiN(SO 2F) 2中的一种或多种。
优选地，所述锂离子电池非水电解液中所述锂盐的含量为0.5-3mol/L；更优选地，所述锂离子电池非水电解液中所述锂盐的含量为0.7-1.5mol/L。
优选地，所述锂盐选自LiPF 6和/或LiPO 2F 2。
优选地，所述非水电解液进一步包含添加剂，所述添加剂选自不饱和环状碳酸酯、氟代环状碳酸酯、环状磺酸内酯和环状硫酸酯中的一种或多种。
优选地，所述不饱和环状碳酸酯选自碳酸亚乙烯酯、碳酸乙烯亚乙酯和亚甲基碳酸乙烯酯中的一种或多种。
优选地，所述氟代环状碳酸酯选自氟代碳酸乙烯酯、三氟甲基碳酸乙烯酯和双氟代碳酸乙烯酯中的一种或多种。
优选地，所述环状磺酸内酯选自1,3-丙烷磺内酯、1,4-丁烷磺内酯和丙烯基-1,3-磺酸内酯中的一种或多种。
优选地，所述环状硫酸酯选自硫酸乙烯酯、4-甲基硫酸乙烯酯和
Figure PCTCN2021113013-appb-000005
中的一种或多种。
更优选地，所述添加剂为碳酸亚乙烯酯、氟代碳酸乙烯酯、1,3-丙烷磺内酯、
Figure PCTCN2021113013-appb-000006
和硫酸乙烯酯中的一种或多种。
优选地，所述添加剂的含量为所述锂离子电池非水电解液总重量的0.1-5重量％。
本发明第二方面提供一种锂离子电池，所述锂离子电池包括正极、负极、置于正极和负极之间的隔膜以及本发明第一方面所述的锂离子电池非水电解液。
优选地，所述锂离子电池正极的活性材料选自LiNi xCo yM zL (1-x-y-z)O 2、LiCo x’L (1-x’)O 2、LiNi x”L’ y’M (2-x”-y’)O 4和Li z’MPO 4中的一种或多种，
其中，L为Al、Sr、Mg、Ti、Ca、Zr、Zn、Si和Fe中的一种或多种；
L’为Co、Al、Sr、Mg、Ti、Ca、Zr、Zn、Si和Fe中的一种或多种；
M为Fe、Al、Mn和Co中的一种或多种；
且0≤x≤1，0≤y≤1，0≤z≤1，0＜x+y+z≤1，0<x’≤1，0.3≤x”≤0.6，0.01≤y’≤0.2，0.5≤z’≤1。
通过上述技术方案，采用本发明的锂离子电池非水电解液并进一步制备锂离子电池时，可以显著提高锂离子电池在高温下存储和使用时的容量保持率，有效减少电池在存储中的厚度膨胀率。
具体实施方式
在本文中所披露的范围的端点和任何值都不限于该精确的范围或值，这些范围或值应当理解为包含接近这些范围或值的值。对于数值范围来说，各个范围的端点值之间、各个范围的端点值和单独的点值之间，以及单独的点值之间可以彼此组合而得到一个或多个新的数值范围，这些数值范围应被视为在本文中具体公开。
本发明第一方面提供一种锂离子电池非水电解液，所述非水电解液包含有机溶剂、锂盐以及由以下式(1)和/或式(2)表示的化合物：
Figure PCTCN2021113013-appb-000007
Figure PCTCN2021113013-appb-000008
在式(1)和式(2)中，R 1-R 6各自独立地选自氢、1-6个碳原子的烷基或卤代烷基、1-8个碳原子的醚基或卤代醚基、2-6个碳原子的不饱和烃基或1-6个碳原子的酯基。
根据本发明，优选地，所述1-6个碳原子的烷基选自甲基、乙基、丙基、异丙基、丁基、异丁基、新丁基或叔丁基。
优选地，所述1-6个碳原子的卤代烷基选自烷基中至少一个氢被卤素元素取代的1-6个碳原子的卤代烷基；更优选地，所述卤素元素为氟。
优选地，所述2-6个碳原子的不饱和烃基选自乙烯基、丙烯基、烯丙基、丙炔基、炔丙基、甲基乙烯基或甲基烯丙基。
根据本发明，优选地，所述式(1)表示的化合物选自具有以下结构的化合物中的一种或多种：
Figure PCTCN2021113013-appb-000009
Figure PCTCN2021113013-appb-000010
根据本发明，优选地，所述式(1)表示的化合物选自具有以下结构的化合物中的一种或多种：
Figure PCTCN2021113013-appb-000011
Figure PCTCN2021113013-appb-000012
本发明中，所述式(1)表示的化合物可以按照下述方法合成：
在缚酸剂的存在下，将式(A)表示的化合物与式(B-1)和/或式(B-2)表示的化合物在-10℃到20℃下反应，即可得到式(1)表示的化合物。
Figure PCTCN2021113013-appb-000013
其中，式(A)和式(B)中，R 1-R 4可以各自独立地选自氢、1-6个碳原子的烷基或卤代烷基、1-8个碳原子的醚基或卤代醚基、2-6个碳原子的不 饱和烃基或1-6个碳原子的酯基。
其中，所述缚酸剂可以为本领域的常规选择，例如可以为N,N-二异丙基乙胺(DIEA)、吡啶和三乙胺等，本发明中，优选地，所述缚酸剂为三乙胺。
另外，反应后通过本领域常规的处理方法得到目标化合物即可，例如可以通过柱层析等方法来获得目标化合物。
本发明中，所述式(2)表示的化合物可以按照下述方法合成：首先将以下式(C)表示的化合物与氯化亚砜在30-60℃下反应，得到式(D)表示的化合物；接着，将式(D)表示的化合物在0-60℃条件下与式(E)表示的化合物发生反应，得到式(F)所示化合物；最后，将式(F)所示化合物在三氯化钌的存在下，与氧化剂在-10-50℃的条件下经催化反应后，即可得到式(2)表示的化合物。
Figure PCTCN2021113013-appb-000014
其中，R 5-R 6可以各自独立地选自氢、1-6个碳原子的烷基或卤代烷基、1-8个碳原子的醚基或卤代醚基、2-6个碳原子的不饱和烃基或1-6个碳原子的酯基。
其中，所述氧化剂可以为本领域的常规选择，优选地，所述氧化剂为高碘酸钠、次氯酸钠和次氯酸钙中的一种或多种。
本发明的发明人经过深入的研究发现，当锂离子电池的非水电解液中含有所述式(1)和/或式(2)表示的化合物时，所述锂离子电池的高温循环和存储性能都会得到显著提高。这可能是由于在首次充电过程中，所述式(1)或(2)表示的化合物在电极表面能够发生反应形成钝化膜，从而抑制溶剂分子进一步分解。另外，由其形成的钝化膜耐高温，在高温循环以及存储过程中不会被破坏，而且所述式(1)或式(2)表示的化合物还可以修复因为高温而损坏的钝化膜中的其它成分，从而保证了电池的界面膜在高温下的稳定性，提升电池的高温循环和高温存储性能。
根据本发明，用于制备非水电解液时，所述式(1)表示的化合物的含量可以为所述锂离子电池非水电解液总重量的10ppm以上；优选地，所述式(1)表示的化合物的含量为所述锂离子电池非水电解液总重量的10ppm-3重量％。所述式(2)表示的化合物的含量可以为所述锂离子电池非水电解液总重量的10ppm-1重量％；优选地，所述式(2)表示的化合物的含量为所述锂离子电池非水电解液总重量的10ppm-0.8重量％。
当所述式(1)和/或式(2)表示的化合物的含量在此范围内时，可以有效改善锂离子电池在高温下的存储和循环性能。当所述式(1)和/或式(2)表示的化合物的含量低于此范围时，尽管也有一定的改善效果，但是作用不够明显；当所述式(1)和/或式(2)表示的化合物的含量高于此范围时，反而会使锂离子电池在高温下的存储和循环性能，这可能是由于较高含量式(1)和/或式(2)表示的化合物加入后，使得电解液的粘度增大，进一步导致电池的整体阻抗增加，从而降低高温下的存储和循环性能。
本发明中，所述锂离子电池非水电解液中的有机溶剂可以为本领域常用于制备非水电解液的各种有机溶剂，没有特别地限定，例如，可以使用环状碳酸酯、链状碳酸酯、羧酸酯和醚类等中的一种或多种作为有机溶剂。
根据本发明，优选地，所述有机溶剂为环状碳酸酯和链状碳酸酯的混合物，当所述有机溶剂选自环状碳酸酯和链状碳酸酯的混合物时，可以使非水电解液获得较高的介电常数和较低的粘度。更优选地，所述环状碳酸酯选自碳酸乙烯酯、碳酸丙烯酯和碳酸丁烯酯中的一种或多种；所述链状碳酸酯选自碳酸二甲酯、碳酸二乙酯、碳酸甲乙酯和碳酸甲丙酯中的一种或多种。
在本发明一个特别优选的实施方式中，所述有机溶剂为碳酸乙烯酯(EC)、碳酸二乙酯(DEC)和碳酸甲乙酯(EMC)三者的混合物，且三者的含量比例为1：1：1，通过使用在上述比例范围内的上述三种化合物作为有机溶剂，可以使非水电解液获得较高的电导率，有利于提高电池的综合性能。
根据本发明，所述锂离子电池非水电解液中的锂盐可以使用本领域常用于制备锂离子电池的各种锂盐，没有特别的限定，例如可以选择LiPF 6、LiPO 2F 2、LiBF 4、LiBOB、LiClO 4、LiCF 3SO 3、LiDFOB、LiN(SO 2CF 3) 2、LiN(SO 2F) 2、LiTFSI和LiDFOB等中的一种或多种。本发明中，优选地，所述锂盐选自LiPF 6、LiBF 4、LiPO 2F 2、LiTFSI、LiBOB、LiDFOB和LiN(SO 2F) 2中的一种或多种。更优选地，所述锂盐选自LiPF 6和/或LiPO 2F 2。当使用上述锂盐时，可以显著提高非水电解液的电导率，提升锂离子电池的性能，降低生产成本。
本发明中，所述锂盐的含量可以为本领域锂离子电池中的通常含量，没有特别的限定。本发明中，所述锂离子电池非水电解液中所述锂盐的含量为0.5-3mol/L；优选地，所述锂离子电池非水电解液中所述锂盐的含量为0.7-1.5mol/L。当所述锂盐的含量在此范围内时，可以保证非水电解液的电导率较高，电池综合性能优良。
本发明中，锂离子电池非水电解液中除含有上述式(1)和/或式(2)表示的化合物之外，还可以进一步含有本领域常用于提高锂离子电池性能的各种添加剂，作为这样的添加剂，例如：可以选自不饱和环状碳酸酯、氟代环状碳酸酯、环状磺酸内酯和环状硫酸酯等。
本发明中，优选地，所述不饱和环状碳酸酯选自碳酸亚乙烯酯(CAS：872-36-6)、碳酸乙烯亚乙酯(CAS：4427-96-7)和亚甲基碳酸乙烯酯(CAS：124222-05-5)中的一种或多种。
本发明中，优选地，所述氟代环状碳酸酯选自氟代碳酸乙烯酯(CAS：114435-02-8)、三氟甲基碳酸乙烯酯(CAS：167951-80-6)和双氟代碳酸乙烯酯(CAS：311810-76-1)中的一种或多种。
本发明中，优选地，所述环状磺酸内酯选自1,3-丙烷磺内酯(CAS：1120-71-4)、1,4-丁烷磺内酯(CAS：1633-83-6)和丙烯基-1,3-磺酸内酯(CAS：21806-61-1)中的一种或多种。
本发明中，优选地，所述环状硫酸酯选自硫酸乙烯酯(CAS：1072-53-3)、4-甲基硫酸乙烯酯(CAS：5689-83-8)和
Figure PCTCN2021113013-appb-000015
中的一种或多种。
本发明中，更优选地，所述添加剂为碳酸亚乙烯酯(VC)、氟代碳酸乙烯酯(FEC)、1,3-丙烷磺内酯(PS)、
Figure PCTCN2021113013-appb-000016
和硫酸乙烯酯(DTD)中的一种或多种。
本发明的发明人发现，当在锂离子电池中进一步添加上述添加剂时，可以与式(1)和/或式(2)表示的化合物发挥协同作用，从而进一步提升锂离子电池的综合性能。
另外，除上述添加剂之外，还可以进一步添加第二锂盐作为添加剂来提高锂离子电池的性能，例如，在本发明一个优选的实施方式中，添加第二锂盐LiN(SO 2F) 2作为添加剂，通过添加作为添加剂的LiN(SO 2F) 2，可以进一步提高锂离子电池的容量保持率和容量恢复率。
本发明中，所述添加剂的含量可以为本领域各种添加剂在锂离子电池中的常规含量。例如，所述添加剂的含量可以为所述锂离子电池非水电解液总重量的0.1-5重量％；优选地，所述添加剂的含量可以为所述锂离子电池非 水电解液总重量的0.1-3重量％；更优选地，所述添加剂的含量可以为所述锂离子电池非水电解液总重量的0.5-1重量％。
本发明第二方面提供一种锂离子电池，该锂离子电池包括正极、负极、置于正极和负极之间的隔膜以及本发明第一方面所述的锂离子电池非水电解液。
根据本发明，所述锂离子电池正极的活性材料可以选自LiNi xCo yM zL (1-x-y-z)O 2、LiCo x’L (1-x’)O 2、LiNi x”L’ y’M (2-x”-y’)O 4和Li z’MPO 4中的一种或多种，其中，L为Al、Sr、Mg、Ti、Ca、Zr、Zn、Si和Fe中的一种或多种；L’为Co、Al、Sr、Mg、Ti、Ca、Zr、Zn、Si和Fe中的一种或多种；M为Fe、Al、Mn和Co中的一种或多种；且0≤x≤1，0≤y≤1，0≤z≤1，0＜x+y+z≤1，0<x’≤1，0.3≤x”≤0.6，0.01≤y’≤0.2，0.5≤z’≤1。
例如，所述锂离子电池正极的活性材料可以用LiNi xCo yM zL (1-x-y-z)O 2来表示，其中，x可以为0.5，y可以为0.2，z可以为0.3，M可以为Mn，即，由此表示的所述锂离子电池正极的活性材料为LiNi 0.5Co 0.2Mn 0.3O 2。
根据本发明，所述负极的活性材料可以选自本领域常用于锂离子电池负极活性材料中的各种材料，没有特别的限定，例如可以为金属锂、石墨类碳材料、硬碳材料、软碳材料、硅基、锡基、锑基、铝基、过渡金属化合物中的一种或多种；本发明中，优选地，所述负极的活性材料为人造石墨、天然石墨和硅碳中的一种或多种。
本发明中，所述锂离子电池正极和负极的制备可以按照本领域常用于制备锂离子电池正极和负极的方法进行，没有特别的限制。例如，可以将正负极的活性材料与导电剂和粘接剂混合，并将混合物分散于有机溶剂，制得浆料，之后将所得浆料涂覆于集流体上并进行干燥和延压等处理。所用导电剂、粘接剂、有机溶剂和集流体等均可采用本领域常用的材料和物质，此处不再赘述。
根据本发明，所述置于正极和负极之间的隔膜可以为本领域常用作隔膜的各种材料，没有特别的限定，例如，可以为聚烯烃类隔膜、聚酰胺类隔膜、聚砜类隔膜、聚磷腈类隔膜、聚醚砜类隔膜、聚醚醚酮类隔膜、聚醚酰胺类隔膜和聚丙烯腈类隔膜中的一种或多种；优选地，所述隔膜选自聚烯烃类隔膜和/或聚丙烯腈类隔膜。
本发明中，所述锂离子电池的制备可以采用本领域常用的“三明治”法进行，例如，在涂覆有活性材料的正极板和负极板之间放置隔膜，然后将其整体进行卷绕，再将卷绕体压扁后放入包装袋内真空烘烤干燥，得到电芯，接着，将电解液注入电芯中，真空封装并静置之后进行化成即可。此方法为 本领域的常规方法，此处不再赘述。
以下将通过实施例对本发明进行详细描述。以下实施例中，如无特别说明，所用材料均为市售品。
以下实施例中，以化合物2为代表的式(2)表示的化合物的制备方法如下：
Figure PCTCN2021113013-appb-000017
在搅拌下，将式(D-1)表示的化合物在0-60℃条件下与式(E-1)表示的化合物发生反应，得到式(F-1)所示化合物；之后，将式(F-1)所示化合物与高碘酸钠、次氯酸钠、次氯酸钙等氧化剂在-10-50℃的条件下经三氯化钌催化后，即可得到化合物2。
Figure PCTCN2021113013-appb-000018
以下实施例中，以化合物7为代表的式(1)表示的化合物的制备方法如下：
在搅拌下，在缚酸剂三乙胺的存在下，将式(A-1)表示的化合物与式(B-3)表示的化合物在-10℃-20℃下反应，即可得到化合物7。
测试例1：高温循环性能测试
将以下实施例和对比例制备的锂离子电池置于恒温45℃的烘箱中，以1C的电流恒流充电至4.4V(LiNi 0.5Co 0.2Mn 0.3O 2/人造石墨电池)或4.2V(LiNi 0.8Co 0.15Al 0.05O 2/人造石墨电池)或4.48V(LiCoO 2/人造石墨电池)或3.65V(LiFePO 4/人造石墨电池)，再恒压充电至电流下降至0.02C，然后以1C恒流放电至3.0V(LiNi 0.5Co 0.2Mn 0.3O 2/人造石墨电池，LiNi 0.8Co 0.15Al 0.05O 2/人造石墨电池，LiCoO 2/人造石墨电池)或以1C恒流放电至2.5V(LiFePO 4/人造石墨电池)，如此循环300次，记录第1次的放电容量和第300次的放电容量。
按下式计算高温循环的容量保持率：
容量保持率＝第300次的放电容量/第1次的放电容量×100％。
测试例2：高温存储性能测试
将以下实施例和对比例制备的锂离子电池在常温下用1C恒流恒压充至4.4V(LiNi 0.5Co 0.2Mn 0.3O 2/人造石墨电池)或4.2V(LiNi 0.8Co 0.15Al 0.05O 2/人造石墨电池)或4.48V(LiCoO 2/人造石墨电池)或3.65V(LiFePO 4/人造石墨电池)，测量电池初始放电容量及初始电池厚度，然后在60℃环境中储存30天后，以1C恒流放电至3.0V(LiNi 0.5Co 0.2Mn 0.3O 2/人造石墨电池，LiNi 0.8Co 0.15Al 0.05O 2/人造石墨电池，LiCoO 2/人造石墨电池)，或以1C恒流 放电至2.5V(LiFePO 4//人造石墨电池)，测量此时电池的保持容量和恢复容量及储存后电池厚度，计算电池容量保持率、容量恢复率和厚度膨胀率，计算公式如下：
电池容量保持率(％)＝保持容量/初始容量×100％；
电池容量恢复率(％)＝恢复容量/初始容量×100％；
厚度膨胀率(％)＝(储存后电池厚度-初始电池厚度)/初始电池厚度×100％。
实施例1
1)锂离子电池非水电解液的制备
将碳酸乙烯酯(EC)、碳酸二乙酯(DEC)和碳酸甲乙酯(EMC)按重量比为EC:DEC:EMC＝1:1:1进行混合，然后加入六氟磷酸锂(LiPF 6)至摩尔浓度为1mol/L，再加入非水电解液总重量10ppm的化合物1；
2)正极板的制备
将正极活性材料锂镍钴锰氧化物LiNi 0.5Co 0.2Mn 0.3O 2、导电剂导电碳黑Super-P和粘结剂聚偏二氟乙烯(PVDF)按照93:4:3的重量比均匀混合，然后将所得混合物分散于N-甲基-2-吡咯烷酮(NMP)中，得到正极浆料；将正极浆料均匀涂布在铝箔的两面上，经烘干、压延和真空干燥，并用超声波焊机焊上铝制引出线后得到正极板，极板的厚度为120-150μm。
3)负极板的制备
将负极活性材料人造石墨、导电剂导电碳黑Super-P、以及粘结剂丁苯橡胶(SBR)和羧甲基纤维素(CMC)按照94:1:2.5:2.5的重量比混合均匀，然后将混合物分散于去离子水中，得到负极浆料；将负极浆料涂布在铜箔的两面上，经过烘干、压延和真空干燥，并用超声波焊机焊上镍制引出线后得到负极板，极板的厚度为120-150μm。
4)电芯的制备
在正极板和负极板之间放置厚度为20μm的三层隔离膜，然后将正极板、负极板和隔膜组成的三明治结构进行卷绕，再将卷绕体压扁后放入铝箔包装袋，在75℃下真空烘烤48h，得到待注液的电芯。
5)电芯的注液和化成
在露点为-40℃以下的手套箱中，将步骤1)制备的电解液注入步骤4)制备的电芯中，经真空封装后静置24h；
然后按以下步骤进行首次充电的常规化成：0.05C恒流充电180min，0.2C恒流充电至3.95V，进行二次真空封口，然后进一步以0.2C的电流恒流充电至4.4V，常温搁置24hr后，以0.2C的电流恒流放电至3.0V。
实施例2-29以及对比例1-10
按照实施例1的方法进行，不同的是，锂离子电池的正极活性材料、非水电解液中添加的式(1)或式(2)表示的化合物和其他添加剂的种类与含量不同，具体如表1所示。
另外，不同正极活性材料的化成方法不同，具体地，LiNi 0.8Co 0.15Al 0.05O 2/人造石墨电池：0.05C恒流充电180min，0.1C恒流充电180min，0.2C恒流充电120min，进行二次真空封口，然后进一步以0.2C的电流恒流恒压充电至4.2V，截止电流0.05C，常温搁置5min后，以0.2C恒流放电至3V。
LiCoO 2/人造石墨电池：采用热压化成，以0.1C恒流充45min上限电压3.8V，压力8Kg/CC，以0.2C恒流充电30min上限电压4.4V，压力8Kg/CC，以0.5C恒流充电75min上限电压4.4V，压力8Kg/CC，进行二次真空封口，然后进一步以0.2C的电流恒流恒压充电至4.48V，截止电流0.03C，常温搁置5min后，以0.2C恒流放电至3V。
LiFePO 4/人造石墨电池：采用热压化成，以0.03C恒流充120min上限电压3.65V，压力3Kg/CC，以0.1C恒流充电60min上限电压3.65V，压力3Kg/CC，以0.2C恒流充电60min上限电压3.65V，压力6Kg/CC，进行二次真空封口，然后进一步以0.2C的电流恒流恒压充电至3.65V，截止电流0.05C，常温搁置5min后，以0.2C恒流放电至2.5V。
实施例1-29及对比例1-10制备的锂离子电池的相关性能如表1所示。
表1
Figure PCTCN2021113013-appb-000019
Figure PCTCN2021113013-appb-000020
注：表1中/表示未添加相应物质。
通过实施例1-8以及对比例1的结果可以看出，当锂离子电池非水电解液中含有本发明式(1)或式(2)表示的化合物时，与未使用上述化合物的对比例相比，可以显著提高锂离子电池在高温下的存储和循环性能。
另外，由实施例4、实施例9-14以及对比例2-7的结果对比可知，当在锂离子电池的非水电解液中进一步添加其他添加剂(碳酸亚乙烯酯、氟代碳酸乙烯酯、1,3-丙烷磺内酯、
Figure PCTCN2021113013-appb-000021
硫酸乙烯酯和LiN(SO 2F) 2)时，可 以进一步提高锂离子电池的在高温下循环和存储的性能。
由表1还可以看出，增加化合物1的添加量(参考实施例1和实施例4)可以显著提高锂离子电池的容量保持率和容量恢复率，但是，当化合物1的添加量继续增加时(参考实施例7和实施例8)，反而会降低锂离子电池的性能。
通过实施例15-29以及对比例8-10的结果可以看出，除正极活性材料LiNi 0.5Co 0.2Mn 0.3O 2之外，当锂离子电池正极活性材料为LiNi 0.8Co 0.15Al 0.05O 2、LiCoO 2以及LiFePO 4，且非水电解液中含有本发明提供的式(1)和/或式(2)表示的化合物时，所得锂离子电池的高温循环和存储性能均可得到显著的提高。
以上详细描述了本发明的优选实施方式，但是，本发明并不限于此。在本发明的技术构思范围内，可以对本发明的技术方案进行多种简单变型，包括各个技术特征以任何其它的合适方式进行组合，这些简单变型和组合同样应当视为本发明所公开的内容，均属于本发明的保护范围。

Claims (10)

  1. 一种锂离子电池非水电解液，其特征在于，所述非水电解液包含有机溶剂、锂盐以及由以下式(1)和/或式(2)表示的化合物：
    Figure PCTCN2021113013-appb-100001
    在式(1)和式(2)中，R 1-R 6各自独立地选自氢、1-6个碳原子的烷基或卤代烷基、1-8个碳原子的醚基或卤代醚基、2-6个碳原子的不饱和烃基或1-6个碳原子的酯基。
  2. 根据权利要求1所述的锂离子电池非水电解液，其中，所述1-6个碳原子的烷基选自甲基、乙基、丙基、异丙基、丁基、异丁基、新丁基或叔丁基；
    优选地，所述1-6个碳原子的卤代烷基选自烷基中至少一个氢被卤素元素取代的1-6个碳原子的卤代烷基；
    更优选地，所述卤素元素为氟；
    优选地，所述2-6个碳原子的不饱和烃基选自乙烯基、丙烯基、烯丙基、丙炔基、炔丙基、甲基乙烯基或甲基烯丙基。
  3. 根据权利要求1或2所述的锂离子电池非水电解液，其中，所述式(1)的化合物选自具有以下结构的化合物中的一种或多种：
    Figure PCTCN2021113013-appb-100002
  4. 根据权利要求1或2所述的锂离子电池非水电解液，其中，所述式(2)的化合物选自具有以下结构的化合物中的一种或多种：
    Figure PCTCN2021113013-appb-100003
    Figure PCTCN2021113013-appb-100004
  5. 根据权利要求1-4中任意一项所述的锂离子电池非水电解液，其中，所述式(1)表示的化合物的含量为所述锂离子电池非水电解液总重量的10ppm以上；
    优选地，所述式(1)表示的化合物的含量为所述锂离子电池非水电解液总重量的10ppm-3重量％；
    优选地，所述式(2)表示的化合物的含量为所述锂离子电池非水电解液总重量的10ppm-1重量％；
    优选地，所述式(2)表示的化合物的含量为所述锂离子电池非水电解液总重量的10ppm-0.8重量％。
  6. 根据权利要求1-4中任意一项所述的锂离子电池非水电解液，其中，所述有机溶剂为环状碳酸酯和链状碳酸酯的混合物；
    优选地，所述环状碳酸酯选自碳酸乙烯酯、碳酸丙烯酯、碳酸丁烯酯和碳酸丁烯酯中的一种或多种；
    优选地，所述链状碳酸酯选自碳酸二甲酯、碳酸二乙酯、碳酸甲乙酯和碳酸甲丙酯中的一种或多种。
  7. 根据权利要求1-4中任意一项所述的锂离子电池非水电解液，其中，所述锂盐选自LiPF 6、LiBF 4、LiPO 2F 2、LiTFSI、LiBOB、LiDFOB、LiTFSI、LiSbF 6、LiAsF 6、LiN(SO 2CF 3) 2、LiC(SO 2CF 3) 3和LiN(SO 2F) 2中的一种或多种，
    优选地，所述锂离子电池非水电解液中所述锂盐的含量为0.5-3mol/L；
    优选地，所述锂盐选自LiPF 6和/或LiPO 2F 2；
    优选地，所述锂离子电池非水电解液中所述锂盐的含量为0.7-1.5mol/L。
  8. 根据权利要求1-4中任意一项所述的锂离子电池非水电解液，其中， 所述锂离子电池非水电解液进一步包含添加剂，所述添加剂选自不饱和环状碳酸酯、氟代环状碳酸酯、环状磺酸内酯和环状硫酸酯中的一种或多种；
    优选地，所述不饱和环状碳酸酯选自碳酸亚乙烯酯、碳酸乙烯亚乙酯和亚甲基碳酸乙烯酯中的一种或多种；
    优选地，所述氟代环状碳酸酯选自氟代碳酸乙烯酯、三氟甲基碳酸乙烯酯和双氟代碳酸乙烯酯中的一种或多种；
    优选地，所述环状磺酸内酯选自1,3-丙烷磺内酯、1,4-丁烷磺内酯和丙烯基-1,3-磺酸内酯中的一种或多种；
    优选地，所述环状硫酸酯选自硫酸乙烯酯、4-甲基硫酸乙烯酯和
    Figure PCTCN2021113013-appb-100005
    中的一种或多种；
    更优选地，所述添加剂为碳酸亚乙烯酯、氟代碳酸乙烯酯、1,3-丙烷磺内酯、
    Figure PCTCN2021113013-appb-100006
    和硫酸乙烯酯中的一种或多种；
    优选地，所述添加剂的含量为所述锂离子电池非水电解液总重量的0.1-5重量％。
  9. 一种锂离子电池，其特征在于，所述锂离子电池包括正极、负极、置于正极和负极之间的隔膜以及权利要求1-8中任意一项所述的锂离子电池非水电解液。
  10. 根据权利要求9所述的锂离子电池，其特征在于，所述锂离子电池正极的活性材料选自LiNi xCo yM zL (1-x-y-z)O 2、LiCo x’L (1-x’)O 2、LiNi x”L’ y’M (2-x”-y’)O 4和Li z’MPO 4中的一种或多种，
    其中，L为Al、Sr、Mg、Ti、Ca、Zr、Zn、Si和Fe中的一种或多种；
    L’为Co、Al、Sr、Mg、Ti、Ca、Zr、Zn、Si和Fe中的一种或多种；
    M为Fe、Al、Mn和Co中的一种或多种；
    且0≤x≤1，0≤y≤1，0≤z≤1，0＜x+y+z≤1，0<x’≤1，0.3≤x”≤0.6，0.01≤y’≤0.2，0.5≤z’≤1。
PCT/CN2021/113013 2020-08-31 2021-08-17 锂离子电池非水电解液以及锂离子电池 WO2022042374A1 (zh)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202010899847.3 2020-08-31
CN202010899847.3A CN114122493A (zh) 2020-08-31 2020-08-31 锂离子电池非水电解液以及锂离子电池

Publications (1)

Publication Number Publication Date
WO2022042374A1 true WO2022042374A1 (zh) 2022-03-03

Family

ID=80354588

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2021/113013 WO2022042374A1 (zh) 2020-08-31 2021-08-17 锂离子电池非水电解液以及锂离子电池

Country Status (2)

Country Link
CN (1) CN114122493A (zh)
WO (1) WO2022042374A1 (zh)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116830298A (zh) * 2022-04-29 2023-09-29 宁德时代新能源科技股份有限公司 二次电池、电池模块、电池包和用电装置

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103053060A (zh) * 2010-08-05 2013-04-17 和光纯药工业株式会社 非水系电解液和使用其的非水系电解液电池
CN103107355A (zh) * 2013-02-03 2013-05-15 宁德新能源科技有限公司 锂离子电池及其电解液
JP2016029650A (ja) * 2014-07-17 2016-03-03 三菱化学株式会社 非水系電解液及びそれを用いた非水系電解液電池
CN105474452A (zh) * 2013-09-25 2016-04-06 三井化学株式会社 电池用非水电解液及锂二次电池
WO2017069278A1 (ja) * 2015-10-23 2017-04-27 宇部興産株式会社 非水電解液及びそれを用いた蓄電デバイス

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103053060A (zh) * 2010-08-05 2013-04-17 和光纯药工业株式会社 非水系电解液和使用其的非水系电解液电池
CN103107355A (zh) * 2013-02-03 2013-05-15 宁德新能源科技有限公司 锂离子电池及其电解液
CN105474452A (zh) * 2013-09-25 2016-04-06 三井化学株式会社 电池用非水电解液及锂二次电池
JP2016029650A (ja) * 2014-07-17 2016-03-03 三菱化学株式会社 非水系電解液及びそれを用いた非水系電解液電池
WO2017069278A1 (ja) * 2015-10-23 2017-04-27 宇部興産株式会社 非水電解液及びそれを用いた蓄電デバイス

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116830298A (zh) * 2022-04-29 2023-09-29 宁德时代新能源科技股份有限公司 二次电池、电池模块、电池包和用电装置

Also Published As

Publication number Publication date
CN114122493A (zh) 2022-03-01

Similar Documents

Publication Publication Date Title
WO2022042373A1 (zh) 锂离子电池
WO2019119766A1 (zh) 一种非水电解液及锂离子电池
EP3483972B1 (en) Non-aqueous electrolyte solution for lithium-ion battery, and lithium-ion battery using the same
EP4231406A1 (en) Secondary battery
WO2023241428A1 (zh) 一种锂离子电池
WO2024037187A1 (zh) 一种锂离子电池
WO2023246279A1 (zh) 一种锂二次电池
WO2021238052A1 (zh) 一种锂离子二次电池的电解液及其应用
WO2021238531A1 (zh) 一种非水电解液及锂离子电池
WO2022042374A1 (zh) 锂离子电池非水电解液以及锂离子电池
CN111384438B (zh) 一种锂离子电池非水电解液及锂离子电池
CN112310474A (zh) 锂离子电池非水电解液及包含该电解液的锂离子电池
WO2023016412A1 (zh) 一种非水电解液及电池
CN113611911B (zh) 一种锂离子电池
CN113871712B (zh) 锂离子电池电解液及其制备方法和锂离子电池
WO2023016411A1 (zh) 一种非水电解液及电池
CN111384439A (zh) 一种非水电解液及锂离子电池
WO2023279953A1 (zh) 一种非水电解液及电池
WO2022218145A1 (zh) 一种非水电解液及锂离子电池
CN111490292B (zh) 非水电解液功能添加剂、非水电解液及锂离子电池
WO2022143190A1 (zh) 一种非水电解液及电池
EP4243146A1 (en) Lithium ion battery non-aqueous electrolyte and lithium ion battery
CN112310466B (zh) 锂离子电池非水电解液及包含该电解液的锂离子电池
CN114447430A (zh) 锂离子电池
CN110247116A (zh) 一种锂离子电池非水电解液及使用该电解液的锂离子电池

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 21860212

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 21860212

Country of ref document: EP

Kind code of ref document: A1