CN116779961A - Lithium ion battery electrolyte, lithium ion battery and vehicle - Google Patents
Lithium ion battery electrolyte, lithium ion battery and vehicle Download PDFInfo
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- CN116779961A CN116779961A CN202310308312.8A CN202310308312A CN116779961A CN 116779961 A CN116779961 A CN 116779961A CN 202310308312 A CN202310308312 A CN 202310308312A CN 116779961 A CN116779961 A CN 116779961A
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- ion battery
- lithium ion
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- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims abstract description 80
- 229910001416 lithium ion Inorganic materials 0.000 title claims abstract description 80
- 239000003792 electrolyte Substances 0.000 title claims abstract description 72
- 150000001875 compounds Chemical class 0.000 claims abstract description 78
- -1 nitrile compound Chemical class 0.000 claims abstract description 38
- 239000007774 positive electrode material Substances 0.000 claims abstract description 9
- 125000004432 carbon atom Chemical group C* 0.000 claims abstract description 8
- 125000000217 alkyl group Chemical group 0.000 claims abstract description 4
- 125000002947 alkylene group Chemical group 0.000 claims abstract description 4
- 229910052744 lithium Inorganic materials 0.000 claims description 22
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 18
- 229910003002 lithium salt Inorganic materials 0.000 claims description 14
- 159000000002 lithium salts Chemical class 0.000 claims description 14
- 239000000654 additive Substances 0.000 claims description 10
- 230000000996 additive effect Effects 0.000 claims description 10
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 claims description 8
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 claims description 8
- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 claims description 7
- 239000006183 anode active material Substances 0.000 claims description 7
- BTBUEUYNUDRHOZ-UHFFFAOYSA-N Borate Chemical compound [O-]B([O-])[O-] BTBUEUYNUDRHOZ-UHFFFAOYSA-N 0.000 claims description 6
- VAYTZRYEBVHVLE-UHFFFAOYSA-N 1,3-dioxol-2-one Chemical compound O=C1OC=CO1 VAYTZRYEBVHVLE-UHFFFAOYSA-N 0.000 claims description 5
- 239000002131 composite material Substances 0.000 claims description 5
- VUPKGFBOKBGHFZ-UHFFFAOYSA-N dipropyl carbonate Chemical compound CCCOC(=O)OCCC VUPKGFBOKBGHFZ-UHFFFAOYSA-N 0.000 claims description 5
- KKQAVHGECIBFRQ-UHFFFAOYSA-N methyl propyl carbonate Chemical compound CCCOC(=O)OC KKQAVHGECIBFRQ-UHFFFAOYSA-N 0.000 claims description 5
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 claims description 5
- SBLRHMKNNHXPHG-UHFFFAOYSA-N 4-fluoro-1,3-dioxolan-2-one Chemical compound FC1COC(=O)O1 SBLRHMKNNHXPHG-UHFFFAOYSA-N 0.000 claims description 4
- 239000003125 aqueous solvent Substances 0.000 claims description 4
- VEWLDLAARDMXSB-UHFFFAOYSA-N ethenyl sulfate;hydron Chemical compound OS(=O)(=O)OC=C VEWLDLAARDMXSB-UHFFFAOYSA-N 0.000 claims description 4
- IGILRSKEFZLPKG-UHFFFAOYSA-M lithium;difluorophosphinate Chemical compound [Li+].[O-]P(F)(F)=O IGILRSKEFZLPKG-UHFFFAOYSA-M 0.000 claims description 4
- 229910052710 silicon Inorganic materials 0.000 claims description 4
- 229910018040 Li 1+x Ni Inorganic materials 0.000 claims description 3
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 claims description 3
- 239000000956 alloy Substances 0.000 claims description 3
- 239000003575 carbonaceous material Substances 0.000 claims description 3
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 claims description 3
- MHCFAGZWMAWTNR-UHFFFAOYSA-M lithium perchlorate Chemical compound [Li+].[O-]Cl(=O)(=O)=O MHCFAGZWMAWTNR-UHFFFAOYSA-M 0.000 claims description 3
- 229910001486 lithium perchlorate Inorganic materials 0.000 claims description 3
- 229910001496 lithium tetrafluoroborate Inorganic materials 0.000 claims description 3
- QSZMZKBZAYQGRS-UHFFFAOYSA-N lithium;bis(trifluoromethylsulfonyl)azanide Chemical compound [Li+].FC(F)(F)S(=O)(=O)[N-]S(=O)(=O)C(F)(F)F QSZMZKBZAYQGRS-UHFFFAOYSA-N 0.000 claims description 3
- 150000002736 metal compounds Chemical class 0.000 claims description 3
- 150000004767 nitrides Chemical class 0.000 claims description 3
- 239000010703 silicon Substances 0.000 claims description 3
- 239000002153 silicon-carbon composite material Substances 0.000 claims description 3
- QQUZYDCFSDMNPX-UHFFFAOYSA-N ethene;4-methyl-1,3-dioxolan-2-one Chemical compound C=C.CC1COC(=O)O1 QQUZYDCFSDMNPX-UHFFFAOYSA-N 0.000 claims 1
- 230000000052 comparative effect Effects 0.000 description 18
- 230000000694 effects Effects 0.000 description 11
- 238000002360 preparation method Methods 0.000 description 10
- 230000006872 improvement Effects 0.000 description 8
- 238000000926 separation method Methods 0.000 description 7
- 238000012360 testing method Methods 0.000 description 7
- 239000002904 solvent Substances 0.000 description 5
- 239000011267 electrode slurry Substances 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 238000011056 performance test Methods 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- IQPQWNKOIGAROB-UHFFFAOYSA-N isocyanate group Chemical group [N-]=C=O IQPQWNKOIGAROB-UHFFFAOYSA-N 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 150000002825 nitriles Chemical class 0.000 description 3
- 229910052723 transition metal Inorganic materials 0.000 description 3
- RNFJDJUURJAICM-UHFFFAOYSA-N 2,2,4,4,6,6-hexaphenoxy-1,3,5-triaza-2$l^{5},4$l^{5},6$l^{5}-triphosphacyclohexa-1,3,5-triene Chemical compound N=1P(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP=1(OC=1C=CC=CC=1)OC1=CC=CC=C1 RNFJDJUURJAICM-UHFFFAOYSA-N 0.000 description 2
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 241001391944 Commicarpus scandens Species 0.000 description 2
- 229910013075 LiBF Inorganic materials 0.000 description 2
- 229910013870 LiPF 6 Inorganic materials 0.000 description 2
- 229910019142 PO4 Inorganic materials 0.000 description 2
- 239000002033 PVDF binder Substances 0.000 description 2
- 239000011149 active material Substances 0.000 description 2
- 239000010405 anode material Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 239000001768 carboxy methyl cellulose Substances 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 239000003063 flame retardant Substances 0.000 description 2
- 125000000524 functional group Chemical group 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 239000012948 isocyanate Substances 0.000 description 2
- 150000002513 isocyanates Chemical class 0.000 description 2
- VDVLPSWVDYJFRW-UHFFFAOYSA-N lithium;bis(fluorosulfonyl)azanide Chemical compound [Li+].FS(=O)(=O)[N-]S(F)(=O)=O VDVLPSWVDYJFRW-UHFFFAOYSA-N 0.000 description 2
- 230000014759 maintenance of location Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 2
- 239000010452 phosphate Substances 0.000 description 2
- 239000002985 plastic film Substances 0.000 description 2
- 229920006255 plastic film Polymers 0.000 description 2
- 239000002861 polymer material Substances 0.000 description 2
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 230000002195 synergetic effect Effects 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- ABRVLXLNVJHDRQ-UHFFFAOYSA-N [2-pyridin-3-yl-6-(trifluoromethyl)pyridin-4-yl]methanamine Chemical compound FC(C1=CC(=CC(=N1)C=1C=NC=CC=1)CN)(F)F ABRVLXLNVJHDRQ-UHFFFAOYSA-N 0.000 description 1
- DPXJVFZANSGRMM-UHFFFAOYSA-N acetic acid;2,3,4,5,6-pentahydroxyhexanal;sodium Chemical compound [Na].CC(O)=O.OCC(O)C(O)C(O)C(O)C=O DPXJVFZANSGRMM-UHFFFAOYSA-N 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 229910021383 artificial graphite Inorganic materials 0.000 description 1
- 125000004429 atom Chemical group 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000002041 carbon nanotube Substances 0.000 description 1
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 1
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 239000006258 conductive agent Substances 0.000 description 1
- 239000011889 copper foil Substances 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000009831 deintercalation Methods 0.000 description 1
- 239000008367 deionised water Substances 0.000 description 1
- 229910021641 deionized water Inorganic materials 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- BVWQQMASDVGFGI-UHFFFAOYSA-N ethene propyl hydrogen carbonate Chemical compound C(CC)OC(O)=O.C=C BVWQQMASDVGFGI-UHFFFAOYSA-N 0.000 description 1
- CYEDOLFRAIXARV-UHFFFAOYSA-N ethyl propyl carbonate Chemical compound CCCOC(=O)OCC CYEDOLFRAIXARV-UHFFFAOYSA-N 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 238000009830 intercalation Methods 0.000 description 1
- 230000002687 intercalation Effects 0.000 description 1
- 230000037427 ion transport Effects 0.000 description 1
- 125000001810 isothiocyanato group Chemical group *N=C=S 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 238000011076 safety test Methods 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 235000019812 sodium carboxymethyl cellulose Nutrition 0.000 description 1
- 229920001027 sodium carboxymethylcellulose Polymers 0.000 description 1
- 230000002269 spontaneous effect Effects 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- 238000010189 synthetic method Methods 0.000 description 1
- 239000002341 toxic gas Substances 0.000 description 1
- 238000009461 vacuum packaging Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
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
- H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
- H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
- H01M10/0566—Liquid materials
- H01M10/0567—Liquid materials characterised by the additives
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—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
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
The invention belongs to the field of lithium ion batteries, and particularly relates to a lithium ion battery electrolyte and a lithium ion battery. The lithium ion battery electrolyte provided by the invention comprises a first compound and a second compound, wherein the structure of the first compound is shown as follows:wherein R is 1 、R 2 、R 3 Each independently selected from alkyl groups having 1 to 4 carbon atoms; r is R 4 Selected from alkylene groups having 1 to 5 carbon atoms; the second compound is a nitrile compound. The lithium ion battery electrolyte provided by the embodiment of the invention can eliminate HF and H generated under high temperature conditions 2 O, can effectively prevent HF and H 2 O attacks CEI and the surface of the positive electrode material, and improves the temperatureThe stability of the interface of the positive electrode is improved, so that the thermal stability of the lithium ion battery is improved, and meanwhile, the lithium ion battery can keep good electrochemical performance.
Description
Technical Field
The invention belongs to the technical field of energy storage, and particularly relates to lithium ion battery electrolyte, and further relates to a lithium ion battery, in particular to a vehicle.
Background
Lithium ion batteries have the advantages of high voltage, high energy density and long cycle life, and along with the continuous popularization of electric vehicles, lithium ion power batteries also become one of the secondary batteries with the widest application range. With the progress of technology and the widening of application fields, more demands are put on batteries in addition to energy density. Recently, the spontaneous combustion phenomenon of the automobile using the lithium ion battery is frequently exposed, so that the safety performance of the lithium ion battery needs to be further improved, the safety concern in the heart of a purchaser is eliminated, and the market share of the lithium ion battery automobile is improved.
Generally, a commercial lithium ion battery consists of a cathode, an anode, a separator, and an electrolyte. When the local temperature of the lithium ion battery increases, there is a possibility that the reaction inside the battery is out of control, so that a large amount of toxic gas may be generated. In addition, the electrolyte lithium salt in the electrolyte at high temperature also has an unstable factor, is easily decomposed into HF in the presence of trace water, causes the acidity of the electrolyte to be increased, and damages the electrode material to form potential safety hazards. Researchers are continually trying to improve on the positive electrode, the negative electrode, the electrolyte, the separator material and the battery structure to seek a solution for improving the safety performance of the lithium ion battery, and after a great deal of research work, the electrolyte of the lithium ion battery is found to be important for the safety performance of the battery.
At present, the safety performance of the lithium ion battery is improved mainly by adding the flame-retardant additive into the electrolyte, and the commonly used flame-retardant additive is a phosphate additive, but the phosphate substance has the problems of high viscosity, low solubility of lithium salt, poor compatibility with a negative electrode and the like, so that the electrochemical performance of the lithium ion battery can be reduced, the electrochemical stability of the phosphorus-containing substance is poor, the decomposition is easy to occur, and the safety and the electrochemical performance of the lithium ion battery cannot be considered.
Therefore, research and improvement are needed for the electrolyte of the lithium ion battery to effectively improve the safety performance of the lithium ion battery and simultaneously maintain good electrochemical performance of the lithium ion battery.
Disclosure of Invention
The present invention aims to solve at least one of the technical problems in the related art to some extent. To this end, embodiments of the present invention provide a lithium ion battery electrolyte capable of eliminating HF and H generated under high temperature conditions 2 And O, thereby improving the stability of the positive electrode interface at high temperature and improving the thermal stability of the lithium ion battery.
The lithium ion battery electrolyte provided by the embodiment of the invention comprises a first compound and a second compound, wherein the structure of the first compound is as follows:
wherein R is 1 、R 2 、R 3 Each independently selected from alkyl groups having 1 to 4 carbon atoms; r is R 4 Selected from alkylene groups having 1 to 5 carbon atoms
The second compound is a nitrile compound.
The lithium ion battery electrolyte provided by the embodiment of the invention has the advantages and technical effects that:
1. in the embodiment of the invention, the silicon-oxygen bond of the first compound is easy to break and capture HF and H 2 O, and isocyanate can also absorb HF and H 2 O, when the cell is heated, the two functional groups in the first compound can doubly eliminate HF and H generated under the high temperature condition 2 O, can effectively block HF and H 2 O attacks CEI and the surface of the positive electrode material, so that the stability of the positive electrode interface at high temperature is improved, and the thermal stability of the lithium ion battery is improved;
2. in the embodiment of the invention, the nitrile compound of the second compound can be complexed with the transition metal element through the lone pair electron, so that the stability of the positive electrode interface is improved;
3. according to the embodiment of the invention, the first compound and the second compound nitrile compound are added into the electrolyte at the same time, so that a synergistic effect can be achieved between the first compound and the second compound nitrile compound, the thermal safety performance of the battery core can be remarkably improved, and the lithium ion battery can maintain good high-low temperature performance.
In some embodiments, the electrolyte comprises 0.15-2% by mass of the first compound and 0.3-3% by mass of the second compound, preferably 0.2-1.5% by mass of the first compound and 0.5-2% by mass of the second compound.
In some embodiments, the first compound comprises at least one of the following compounds:
in some embodiments, the second compound comprises at least one of the following compounds:
in some embodiments, the electrolyte further comprises a negative electrode additive, wherein the negative electrode additive comprises at least one of fluoroethylene carbonate, vinylene carbonate, vinyl sulfate.
In some embodiments, the electrolyte further comprises a lithium salt, preferably the lithium salt comprises at least one of lithium hexafluorophosphate, lithium difluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium perchlorate, lithium bis-fluorosulfonyl imide, lithium bis-trifluoromethanesulfonyl imide, lithium bis-oxalato borate, or lithium difluorooxalato borate, and the concentration of the lithium salt in the electrolyte is 0.7 to 1.3mol/L.
In some embodiments, the electrolyte further comprises a non-aqueous solvent comprising at least one of a cyclic carbonate compound or a chain ester compound, preferably the carbonate compound comprises at least one of Ethylene Carbonate (EC), propylene Carbonate (PC), and the chain ester compound comprises at least one of diethyl carbonate (DEC), methyl ethyl carbonate (EMC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl Propyl Carbonate (MPC), ethylene Propyl Carbonate (EPC), or Methyl Ethyl Carbonate (MEC).
The embodiment of the invention also provides a lithium ion battery, which comprises a positive electrode, a negative electrode, a separation film and the electrolyte.
The lithium ion battery provided by the embodiment of the invention has all technical characteristics of the lithium ion battery electrolyte provided by the embodiment of the invention, so that the lithium ion battery provided by the embodiment of the invention has all advantages and technical effects, and the details are not repeated here.
In some embodiments, the positive electrode comprises a positive electrode active material that is a layered lithium composite oxide having the general formula Li 1+x Ni a Co b Mn (1-a-b) O 2 Wherein, -0.1 is less than or equal to x is less than or equal to 0.2; a is more than or equal to 0.5 and less than or equal to 1, b is more than or equal to 0.05 and less than or equal to 0.5; the anode includes an anode active material including at least one of a carbon material, a metal compound, an oxide, a sulfide, silicon, a silicon-carbon composite, a nitride of lithium, a lithium metal, an alloy material, or a polymer material.
The embodiment of the invention also provides a vehicle comprising the lithium ion battery.
The vehicle in the embodiment of the present invention has all the technical features of the lithium ion battery in the embodiment of the present invention, so that all the advantages and technical effects of the lithium ion battery in the embodiment of the present invention are provided, and are not described herein.
Detailed Description
The following detailed description of embodiments of the invention is exemplary and intended to be illustrative of the invention and not to be construed as limiting the invention.
The lithium ion battery electrolyte provided by the embodiment of the invention comprises a first compound and a nitrile compound, wherein the structure of the first compound is shown as follows:
wherein R is 1 、R 2 、R 3 Each independently selected from alkyl groups having 1 to 4 carbon atoms; r is R 4 Selected from alkylene groups having 1 to 5 carbon atoms.
In the lithium ion battery electrolyte provided by the embodiment of the invention, the silicon oxygen bond of the first compound is easy to break and capture HF and H 2 O, and isocyanate can also absorb HF and H 2 O, at electricityWhen the core is heated, the two functional groups in the first compound can doubly eliminate HF and H generated under high temperature condition 2 O, can effectively prevent HF and H 2 O attacks CEI and the surface of the positive electrode material, so that the stability of the positive electrode interface at high temperature is improved, and the thermal stability of the lithium ion battery is improved; in the embodiment of the invention, the nitrile compound of the second compound can be complexed with the transition metal element through the lone pair electron, so that the stability of the positive electrode interface is improved; in the embodiment of the invention, the first compound and the nitrile compound are added into the electrolyte at the same time, so that a synergistic effect can be achieved between the first compound and the nitrile compound, the thermal safety performance of the battery core can be obviously improved, and meanwhile, the lithium ion battery can maintain good high-low temperature performance.
In some embodiments, preferably, the mass content of the first compound in the electrolyte is 0.15-2%, such as 0.15%, 0.3%, 0.5%, 0.8%, 1.0%, 1.2%, 1.5%, 1.8%, 2.0%, etc.; the mass content of the second compound is 0.3 to 3%, for example, 0.3%, 0.5%, 0.8%, 1.0%, 1.2%, 1.5%, 1.8%, 2.0%, 2.2%, 2.5%, 2.8%, 3.0%, etc. Further preferably, the mass content of the first compound is 0.2 to 1.5%, and the mass content of the second compound is 0.5 to 2%.
In the embodiment of the invention, the mass content of the first compound and the second compound in the electrolyte is preferably selected, and if the content of the first compound is low, the effective elimination of HF and H generated at high temperature is not facilitated 2 When the content of the first compound is too high, the improvement effect is not obviously improved along with the further improvement of the content; if the nitrile content of the second compound is low, the second compound is unfavorable for being fully complexed with the transition metal element, and when the nitrile content of the second compound is too high, the improvement effect is not obviously improved along with the further improvement of the nitrile content. Therefore, in the embodiment of the invention, the contents of the first compound and the second compound in the electrolyte are limited in the preferred ranges, so that the best effect can be achieved, the waste of raw materials is avoided, and the production cost is favorably controlled.
In some embodiments, preferably, the first compound comprises at least one of the following compounds:
in some embodiments, preferably, the second compound nitrile compound includes at least one of the following compounds:
in some embodiments, preferably, the electrolyte further comprises a negative electrode additive, wherein the negative electrode additive comprises at least one of fluoroethylene carbonate (FEC), vinylene Carbonate (VC), and vinyl sulfate (DTD).
In the embodiment of the invention, a negative electrode additive can be further added into the electrolyte to further improve the capacity, the cycle performance and the low-temperature performance of the lithium ion battery.
In some embodiments, preferably, the electrolyte further comprises a lithium salt. Further preferably, the lithium salt comprises lithium hexafluorophosphate (LiPF 6 ) Lithium difluorophosphate (LiPO) 2 F 2 ) Lithium tetrafluoroborate (LiBF) 4 ) Lithium hexafluoroarsenate, lithium perchlorate, lithium bis (fluorosulfonyl) imide (LiLSI), lithium bis (trifluoromethylsulfonyl) imide (LiTFSI), lithium bis (oxalato) borate (LiB (C) 2 O 4 ) 2 ) And lithium difluorooxalato borate (LiBF) 2 (C 2 O 4 ) At least one of). Further preferably, the content of the lithium salt is 0.7 to 1.3mol/L, for example, 0.7mol/L, 0.8mol/L, 0.9mol/L, 1.0mol/L, 1.1mol/L, 1.2mol/L, 1.3mol/L, etc.
The electrolyte serves as one of the important components in the lithium ion battery, and serves as an ion transport function between the positive electrode and the negative electrode, while the lithium salt serves as a key component of the electrolyte, which is an important factor determining the performance of the electrolyte. In the embodiment of the invention, the lithium salt is added into the electrolyte, so that the electrolyte has higher conductivity, and meanwhile, the embodiment of the invention prefers the lithium salt which can be adopted, so that the performance of the lithium ion battery is further improved.
In some embodiments, preferably, the electrolyte further comprises a non-aqueous solvent, wherein the non-aqueous solvent comprises at least one of a cyclic carbonate compound, a chain ester compound. Further preferably, the carbonate compound includes at least one of Ethylene Carbonate (EC), propylene Carbonate (PC); the chain ester compound includes at least one of diethyl carbonate (DEC), methyl ethyl carbonate (EMC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl Propyl Carbonate (MPC), ethyl Propyl Carbonate (EPC), and Methyl Ethyl Carbonate (MEC).
In the embodiment of the invention, the nonaqueous solvent is added into the electrolyte, and the type of nonaqueous solvent is optimized, so that the solvent has better compatibility with other components of the electrolyte, and the first compound, the second compound nitrile compound, the negative electrode additive, the lithium salt and the like can be well dispersed in the solvent to form uniform electrolyte, thereby improving the safety performance of the lithium ion battery.
The embodiment of the invention also provides a lithium ion battery, which comprises a positive electrode, a negative electrode, a separation film and the electrolyte.
The lithium ion battery provided by the embodiment of the invention has all technical characteristics of the lithium ion battery electrolyte provided by the embodiment of the invention, so that all advantages and technical effects brought by the lithium ion electrolyte provided by the embodiment of the invention are provided, and the details are not repeated here.
In some embodiments, preferably, the positive electrode includes a positive electrode current collector and a positive electrode active material layer on a surface thereof, the positive electrode active material layer including a positive electrode active material and a conductive agent, wherein the positive electrode active material is a layered lithium composite oxide. Further preferably, the layered lithium composite oxide has the general formula of Li 1+x Ni a Co b Mn( 1-a-b )O 2 Wherein, -0.1 is less than or equal to x is less than or equal to 0.2; a is more than or equal to 0.5 and less than or equal to 1, b is more than or equal to 0.05 and less than or equal to 0.5.
In the embodiment of the invention, the anode material is further optimized, which is beneficial to improving the performance of the lithium ion battery.
In some embodiments, preferably, the anode includes an anode current collector and an anode active material layer on the anode current collector, wherein the anode active material layer includes an anode material capable of absorbing and releasing lithium. Further preferably, the anode active material includes at least one of a carbon material, a metal compound, an oxide, a sulfide, silicon, a silicon-carbon composite, a nitride of lithium, a lithium metal, an alloy material, and a polymer material.
In the embodiment of the invention, the anode active material is optimized, the physical and chemical structure properties of the anode active material have decisive influence on the intercalation and deintercalation of lithium ions, the active material which is easy to deintercalate the lithium ions is used, the structure change of the active material is small during charge and discharge circulation, and the small change is reversible, thereby being beneficial to prolonging the charge and discharge circulation life of the lithium ion battery.
The embodiment of the invention also provides a vehicle comprising the lithium ion battery.
The vehicle of the embodiment of the present invention has all technical features of the lithium ion battery of the embodiment of the present invention, so that all advantages and technical effects brought by the lithium ion of the embodiment of the present invention are provided, and are not described herein.
The present invention will be described in detail with reference to specific examples.
The chemicals used in the examples and comparative examples described below are commercially available or are obtained by prior art synthetic methods.
Preparation of lithium ion battery
Example 1
Preparation of electrolyte: mixing Ethylene Carbonate (EC) and diethyl carbonate (EMC) according to a weight ratio of 3:7 under argon, adding 0.3wt% of ethylene carbonate (VC), adding 1-2 (first compound) and 2-2 (second nitrile compound) with a mass content of 1.0%, and addingLiPF 6 Uniformly mixing to form electrolyte, wherein LiPF 6 1.15mol/L followed by 1wt% of vinyl sulfate (DTD), wherein each content is based on the total mass of the electrolyte.
Preparation of positive electrode: liNi is added to 0.8 Co 0.1 Mn 0.1 (NCM 622), conductive carbon (SP), carbon Nanotubes (CNTs), and polyvinylidene fluoride (PVDF) according to about 96:1:0.5:2.5 weight percent is mixed in solvent N-methyl pyrrolidone, and the mixture is stirred uniformly to obtain positive electrode slurry. And (3) taking aluminum foil as a positive electrode current collector, baking the positive electrode current collector coated with the positive electrode slurry at 120 ℃ for 1 hour, and then carrying out cold pressing, cutting and slitting to prepare the positive electrode.
Preparation of the negative electrode: artificial graphite, sodium carboxymethyl cellulose (CMC) and Styrene Butadiene Rubber (SBR) were mixed according to about 96:2:2, mixing the materials in deionized water in a weight ratio, and uniformly stirring to obtain the negative electrode slurry. The copper foil is adopted as a negative electrode current collector, the negative electrode current collector coated with the negative electrode slurry is baked for 1 hour at 120 ℃, and then cold pressing, cutting and slitting are carried out to prepare the negative electrode.
Assembling a lithium ion battery: and (3) taking a polyethylene film as a separation film, sequentially stacking the positive electrode, the separation film and the negative electrode, enabling the separation film to be positioned in the middle of the positive electrode and the negative electrode to play a role of separation, then winding and loading the separation film into an aluminum plastic film, drying the aluminum plastic film at 80 ℃, injecting prepared electrolyte, and carrying out the procedures of vacuum packaging, standing, formation, shaping and the like to finish the preparation of the lithium ion battery.
Examples 2 to 10
The same preparation method as in example 1 was carried out, except that the kinds and amounts of the first compound and the second compound were different, and the specific kinds and amounts used are shown in Table 1.
Comparative example 1
Comparative example 1 was the same as the preparation method of example 1, except that the first compound and the second compound were not added to the electrolyte.
Comparative example 2
Comparative example 2 was the same as the preparation method of example 1, except that only the first compound 1-1 having a mass fraction of 2.0% was added to the electrolyte.
Comparative example 3
Comparative example 3 was the same as the production method of example 1, except that only 2.0% by mass of nitrile compound 2-1 was added to the electrolyte.
Comparative example 4
Comparative example 4 was the same as the preparation method of example 1, except that the first compound added to the electrolyte was different. The structure of the added first compound is as follows:
comparative example 5
Comparative example 5 was the same as the preparation method of example 1, except that the first compound added to the electrolyte was different. The structure of the added first compound is as follows:
(II) Performance test
1. The lithium ion batteries prepared in examples 1 to 10 and comparative examples 1 to 5 were subjected to thermal safety performance test, the test results are shown in table 1, and the test conditions are as follows:
placing the lithium ion battery finished product in an incubator at 25 ℃ for standing for 30 minutes, charging to 4.25V at a constant charging rate of 1.0 ℃, then charging to 0.05C at a constant voltage, and standing for 5 minutes; placing the battery into a test cabinet, heating at a heating rate of 2 ℃/min, and keeping for 30min when the temperature reaches 135 ℃; if the battery leaks, catches fire and explodes, the battery is considered to be invalid, if the battery does not pass through, the passing rate of the battery is counted:
lithium ion thermal safety pass rate (%) =number of pass cells/total number of test cells×100%
2. The lithium ion batteries prepared in examples 1 to 10 and comparative examples 1 to 5 were subjected to high and low temperature performance tests, the test results are shown in table 1, and the test conditions are as follows:
placing the lithium ion battery finished product in an incubator at 25 ℃ for standing for 30 minutes, charging to 4.25V at a constant charging rate of 1.0C, then charging to 0.05C at a constant voltage, standing for 5 minutes, discharging to 2.8V at 0.2C, and recording the discharge capacity D0; standing for 30min, charging to 4.25V at constant charging rate of 1.0C, then charging to 0.05C at constant voltage, and standing for 5 min; the battery is put into a test cabinet, stored for 24 hours at a high temperature of 60 ℃, then stored for 24 hours at a low temperature of-10 ℃, discharged to 2.8V at 0.2C, and the discharge capacity D1 is recorded:
capacity retention (%) =d1/d0×100%
TABLE 1 electrolyte formulation and thermal safety test results
As can be seen from the data in Table 1, in comparative example 1, the first compound and the second compound of the present invention were not added, and the thermal safety was poor, and the passing rate was 0%. In comparative examples 2 and 3, only one of the first compound and the second compound of the present invention was added, and although there was some improvement in the thermal safety performance of the lithium battery as compared with comparative example 1, the improvement effect was limited and the passing rate was not higher than 30%. In comparative example 4, the first compound added with the electrolyte was introduced with an isothiocyanato group, and contained no isocyanate group, and was not effective in absorbing HF and H 2 O, the thermal safety passing rate can only reach 50%, and the capacity retention rate in the high-low temperature performance test is only 58.1%. In comparative example 5, unlike the first compound added to the electrolyte of example 1, although it also contains an isocyanate group and a siloxane bond, the isocyanate group is directly bonded to the Si atom, and the safety performance is lowered as compared with example 1, and the thermal safety passing rate can be only 60%.
According to the embodiment 1-10 of the invention, the first compound and the second compound are added into the electrolyte, so that the safety performance of the lithium ion battery is effectively improved, the thermal safety passing rate can reach more than 70%, particularly the thermal safety passing rates of the embodiment 3, 4, 5, 7, 9 and 10 can reach 100%, and the lithium ion battery prepared by the embodiment 1-10 of the invention keeps good high-low temperature performance. Meanwhile, the embodiment of the invention further prefers the addition amounts of the first compound and the second compound, and as can be seen from the embodiments 3, 6 and 7, when the first compound is added to a certain content, the thermal safety of the battery can reach 100%, and the improvement effect of the addition amount on the thermal safety is not increased continuously; likewise, it can be seen from examples 8 to 10 that when the nitrile compound as the second compound is added to a certain content, the thermal safety of the lithium battery can already reach 100%, and the effect of improving the thermal safety is not further increased by further increasing the amount. Therefore, in the embodiment of the present invention, the mass content of the first compound is preferably 0.2 to 1.5%, and the mass content of the second compound is preferably 0.5 to 2%.
For purposes of this disclosure, the terms "one embodiment," "some embodiments," "example," "a particular example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.
While the above embodiments have been shown and described, it should be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives, and variations of the above embodiments may be made by those of ordinary skill in the art without departing from the scope of the invention.
Claims (10)
1. The lithium ion battery electrolyte is characterized by comprising a first compound and a second compound, wherein the structural formula of the first compound is shown as follows:
wherein R is 1 、R 2 、R 3 Each independently selected from alkyl groups having 1 to 4 carbon atoms; r is R 4 Selected from alkylene groups having 1 to 5 carbon atoms;
the second compound is a nitrile compound.
2. The lithium ion battery electrolyte according to claim 1, wherein the mass content of the first compound is 0.15 to 2% and the mass content of the second compound is 0.3 to 3% in the electrolyte.
3. The lithium ion battery electrolyte according to claim 1 or 2, wherein the first compound comprises at least one of the following compounds:
4. the lithium ion battery electrolyte according to claim 1 or 2, wherein the second compound comprises at least one of the following compounds:
5. the lithium ion battery electrolyte of claim 1, wherein the electrolyte further comprises a negative electrode additive comprising at least one of fluoroethylene carbonate, vinylene carbonate, and vinyl sulfate.
6. The lithium ion battery electrolyte of claim 1, wherein the electrolyte further comprises a lithium salt comprising at least one of lithium hexafluorophosphate, lithium difluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium perchlorate, lithium difluorosulfonimide, lithium bistrifluoromethane sulfonimide, lithium bisoxalato borate, or lithium difluorooxalato borate, and wherein the concentration of the lithium salt in the electrolyte is 0.7 to 1.3mol/L.
7. The lithium ion battery electrolyte of claim 1, wherein the electrolyte further comprises a non-aqueous solvent comprising at least one of a cyclic carbonate compound or a chain ester compound, wherein the carbonate compound comprises at least one of ethylene carbonate, propylene carbonate, and wherein the chain ester compound comprises at least one of diethyl carbonate, methylethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylene propylene carbonate, or methylethyl carbonate.
8. A lithium ion battery comprising a positive electrode, a negative electrode, a separator and the electrolyte of any one of claims 1 to 7.
9. The lithium ion battery of claim 8, wherein the positive electrode comprises a positive electrode active material that is a layered lithium composite oxide having the general formula Li 1+x Ni a Co b Mn (1-a-b) O 2 Wherein, -0.1 is less than or equal to x is less than or equal to 0.2; a is more than or equal to 0.5 and less than or equal to 1, b is more than or equal to 0.05 and less than or equal to 0.5; and/or the anode comprises an anode active material comprising a carbon material, a metal compound, an oxide, a sulfide, silicon, a silicon-carbon composite, a nitride of lithium, a lithium metal, an alloy material, or a polyAt least one of the composite materials.
10. A vehicle comprising a lithium-ion battery according to claim 8 or 9.
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