CN114094186B - Non-aqueous electrolyte and battery comprising same - Google Patents
Non-aqueous electrolyte and battery comprising same Download PDFInfo
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- CN114094186B CN114094186B CN202111389041.0A CN202111389041A CN114094186B CN 114094186 B CN114094186 B CN 114094186B CN 202111389041 A CN202111389041 A CN 202111389041A CN 114094186 B CN114094186 B CN 114094186B
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- 239000011255 nonaqueous electrolyte Substances 0.000 title claims abstract description 25
- -1 2-propyne-1-yl 1H-imidazole-1-carboxylate Chemical compound 0.000 claims abstract description 43
- XWHSAYMNCUQFFI-UHFFFAOYSA-N 3-(cyanomethylsulfonyl)propanenitrile Chemical compound N#CCS(=O)(=O)CCC#N XWHSAYMNCUQFFI-UHFFFAOYSA-N 0.000 claims abstract description 28
- 239000008151 electrolyte solution Substances 0.000 claims abstract description 24
- GZKHDVAKKLTJPO-UHFFFAOYSA-N ethyl 2,2-difluoroacetate Chemical compound CCOC(=O)C(F)F GZKHDVAKKLTJPO-UHFFFAOYSA-N 0.000 claims abstract description 16
- 239000013538 functional additive Substances 0.000 claims abstract description 11
- 239000000654 additive Substances 0.000 claims description 31
- 230000000996 additive effect Effects 0.000 claims description 29
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 claims description 16
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 claims description 14
- SBLRHMKNNHXPHG-UHFFFAOYSA-N 4-fluoro-1,3-dioxolan-2-one Chemical compound FC1COC(=O)O1 SBLRHMKNNHXPHG-UHFFFAOYSA-N 0.000 claims description 13
- 150000005676 cyclic carbonates Chemical class 0.000 claims description 12
- FKRCODPIKNYEAC-UHFFFAOYSA-N ethyl propionate Chemical compound CCOC(=O)CC FKRCODPIKNYEAC-UHFFFAOYSA-N 0.000 claims description 8
- UHOPWFKONJYLCF-UHFFFAOYSA-N 2-(2-sulfanylethyl)isoindole-1,3-dione Chemical compound C1=CC=C2C(=O)N(CCS)C(=O)C2=C1 UHOPWFKONJYLCF-UHFFFAOYSA-N 0.000 claims description 5
- 150000001733 carboxylic acid esters Chemical class 0.000 claims description 4
- 229910003002 lithium salt Inorganic materials 0.000 claims description 4
- 159000000002 lithium salts Chemical class 0.000 claims description 4
- YKYONYBAUNKHLG-UHFFFAOYSA-N n-Propyl acetate Natural products CCCOC(C)=O YKYONYBAUNKHLG-UHFFFAOYSA-N 0.000 claims description 4
- 239000011356 non-aqueous organic solvent Substances 0.000 claims description 4
- 229940090181 propyl acetate Drugs 0.000 claims description 4
- NQPDZGIKBAWPEJ-UHFFFAOYSA-N valeric acid Chemical compound CCCCC(O)=O NQPDZGIKBAWPEJ-UHFFFAOYSA-N 0.000 claims description 4
- 150000007942 carboxylates Chemical class 0.000 claims description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 claims 1
- 239000003792 electrolyte Substances 0.000 abstract description 15
- 238000000034 method Methods 0.000 abstract description 6
- 230000008569 process Effects 0.000 abstract description 6
- 238000007600 charging Methods 0.000 abstract description 3
- 230000002195 synergetic effect Effects 0.000 abstract description 3
- 238000007086 side reaction Methods 0.000 abstract description 2
- 238000007599 discharging Methods 0.000 abstract 2
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical group [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 12
- 229910001416 lithium ion Inorganic materials 0.000 description 12
- 239000000203 mixture Substances 0.000 description 9
- 229910052744 lithium Inorganic materials 0.000 description 7
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 6
- 238000002360 preparation method Methods 0.000 description 6
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 5
- 229910052782 aluminium Inorganic materials 0.000 description 5
- 229940021013 electrolyte solution Drugs 0.000 description 5
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- 239000011248 coating agent Substances 0.000 description 4
- 238000000576 coating method Methods 0.000 description 4
- 239000002131 composite material Substances 0.000 description 4
- 239000011267 electrode slurry Substances 0.000 description 4
- 239000011888 foil Substances 0.000 description 4
- 239000007773 negative electrode material Substances 0.000 description 4
- 239000007774 positive electrode material Substances 0.000 description 4
- 239000002904 solvent Substances 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 230000009471 action Effects 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000010439 graphite Substances 0.000 description 3
- 229910002804 graphite Inorganic materials 0.000 description 3
- 230000006872 improvement Effects 0.000 description 3
- 230000002265 prevention Effects 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 229910013872 LiPF Inorganic materials 0.000 description 2
- 229910013870 LiPF 6 Inorganic materials 0.000 description 2
- 101150058243 Lipf gene Proteins 0.000 description 2
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 2
- 239000002033 PVDF binder Substances 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- 239000006230 acetylene black Substances 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 239000011230 binding agent Substances 0.000 description 2
- 239000006258 conductive agent Substances 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- 239000010954 inorganic particle Substances 0.000 description 2
- 229910052749 magnesium Inorganic materials 0.000 description 2
- 239000012528 membrane Substances 0.000 description 2
- 239000002905 metal composite material Substances 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 238000011056 performance test Methods 0.000 description 2
- 229920005569 poly(vinylidene fluoride-co-hexafluoropropylene) Polymers 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 2
- 230000009257 reactivity Effects 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- 239000010936 titanium Substances 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 2
- 229910052723 transition metal Inorganic materials 0.000 description 2
- 229910052726 zirconium Inorganic materials 0.000 description 2
- BTBUEUYNUDRHOZ-UHFFFAOYSA-N Borate Chemical compound [O-]B([O-])[O-] BTBUEUYNUDRHOZ-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229910018040 Li 1+x Ni Inorganic materials 0.000 description 1
- 229910012820 LiCoO Inorganic materials 0.000 description 1
- 229910012851 LiCoO 2 Inorganic materials 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-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
- 239000000956 alloy Substances 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000003575 carbonaceous material Substances 0.000 description 1
- 239000001768 carboxy methyl cellulose Substances 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000010277 constant-current charging Methods 0.000 description 1
- 239000011889 copper foil Substances 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 239000008367 deionised water Substances 0.000 description 1
- 229910021641 deionized water Inorganic materials 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- QHGJSLXSVXVKHZ-UHFFFAOYSA-N dilithium;dioxido(dioxo)manganese Chemical compound [Li+].[Li+].[O-][Mn]([O-])(=O)=O QHGJSLXSVXVKHZ-UHFFFAOYSA-N 0.000 description 1
- 238000003411 electrode reaction Methods 0.000 description 1
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000007770 graphite material Substances 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910001496 lithium tetrafluoroborate Inorganic materials 0.000 description 1
- IGILRSKEFZLPKG-UHFFFAOYSA-M lithium;difluorophosphinate Chemical compound [Li+].[O-]P(F)(F)=O IGILRSKEFZLPKG-UHFFFAOYSA-M 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 1
- 229910052706 scandium Inorganic materials 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000002210 silicon-based material Substances 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 235000019812 sodium carboxymethyl cellulose Nutrition 0.000 description 1
- 229920001027 sodium carboxymethylcellulose Polymers 0.000 description 1
- 239000007784 solid electrolyte Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000002562 thickening agent Substances 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- 239000011366 tin-based material Substances 0.000 description 1
- 238000009461 vacuum packaging Methods 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
- 229910052725 zinc Inorganic materials 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
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/058—Construction or manufacture
-
- 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
-
- 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
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 provides a non-aqueous electrolyte and a battery comprising the same, wherein cyanoethylsulfonyl acetonitrile, 2-propyne-1-yl 1H-imidazole-1-carboxylate and ethyl difluoroacetate are used as electrolyte functional additives, the three functional additives can act on a positive interface and a negative interface in a synergistic manner to form a stable interface film, so that the interior of the battery is always kept in a stable state in the charging and discharging circulation process, and based on the stable state, the electrode/electrolyte interface with high stability can effectively inhibit the side reaction of the electrolyte in the charging and discharging circulation process of the battery, improve the circulation stability of the battery, and a battery comprising the nonaqueous electrolytic solution can maintain a stable internal state under overcharge conditions thanks to the highly stable interfacial film, the cycle performance of the battery can be obviously improved, and the prepared battery has excellent overcharge resistance.
Description
Technical Field
The invention belongs to the technical field of batteries, and particularly relates to a non-aqueous electrolyte and a battery comprising the same.
Background
With the advent of the era of electric vehicles, as energy carriers and power sources on electric vehicle systems, the development of batteries has attracted more and more attention, and especially, the improvement of safety performance has become the focus of battery development.
The battery is taken as a complex whole, and each internal part assembly plays a decisive role in the safety performance of the battery; the electrode/electrolyte interface is used as a place where electrode reaction occurs, and plays a decisive role in the performance of the battery, the stable electrode/electrolyte interface can enable the interior of the battery to be kept in a stable state in a long-term charge-discharge cycle process or under an extreme environment condition, on the contrary, the unstable electrode/electrolyte interface can cause decomposition of electrolyte components and increase of interface impedance, so that the cycle life of the battery can be influenced, and safety problems such as fire, explosion and the like caused by gas expansion and large charge-discharge temperature rise can be caused.
Disclosure of Invention
The invention provides a non-aqueous electrolyte and a battery comprising the same, wherein the non-aqueous electrolyte is beneficial to the formation of an SEI (solid electrolyte interface) film with stable performance on a positive electrode interface and a negative electrode interface, so that the battery can realize the remarkable improvement of the cycle life under the normal temperature condition and also has excellent overcharge resistance.
The purpose of the invention is realized by the following technical scheme:
a nonaqueous electrolyte solution comprising a nonaqueous organic solvent, an electrolytic lithium salt, and a functional additive; the functional additive comprises a first additive, a second additive and a third additive, wherein the first additive is cyanoethylsulfonyl acetonitrile, the second additive is 2-propyn-1-yl 1H-imidazole-1-carboxylate, and the third additive is ethyl difluoroacetate;
the mass ratio m of the cyanoethylsulfonyl acetonitrile to the 2-propyne-1-yl 1H-imidazole-1-carboxylic ester to the ethyl difluoroacetate Cyanoethylsulfonylacetonitrile + 2-propyn-1-yl 1H-imidazole-1-carboxylic acid ester :m Difluoroacetic acid ethyl ester The following relationships are satisfied:
m cyanoethylsulfonylacetonitrile + 2-propyn-1-yl 1H-imidazole-1-carboxylic acid ester :m Difluoroacetic acid ethyl ester ＝1:(2～4)；
The mass ratio m of the cyanoethylsulfonyl acetonitrile to the 2-propyn-1-yl 1H-imidazole-1-carboxylic ester Cyanoethylsulfonyl acetonitrile :m 2-propyn-1-yl 1H-imidazole-1-carboxylic acid esters The following relationships are satisfied:
m cyanoethyl sulfonyl acetonitrile :m 2-propyn-1-yl 1H-imidazole-1-carboxylic acid esters ＝1:(1～2)。
In the present invention, m Cyanoethylsulfonylacetonitrile + 2-propyn-1-yl 1H-imidazole-1-carboxylic acid ester The mass percentage of the sum of the mass of the cyanoethylsulfonyl acetonitrile and the mass of the 2-propyn-1-yl 1H-imidazole-1-carboxylic ester to the total mass of the nonaqueous electrolyte is; m is Difluoroacetic acid ethyl ester Is the mass of ethyl difluoroacetateAccounting for the total mass of the non-aqueous electrolyte; m is a unit of Cyanoethyl sulfonyl acetonitrile The mass percentage of the cyanoethyl sulfonyl acetonitrile in the total mass of the non-aqueous electrolyte is; m is 2-propyn-1-yl 1H-imidazole-1-carboxylic acid esters The mass of the 2-propyn-1-yl 1H-imidazole-1-carboxylate accounts for the mass percentage of the total mass of the nonaqueous electrolyte.
The nonaqueous electrolytic solution of the present invention, m Cyanoethyl sulfonyl acetonitrile 0.1 to 1.0 wt.%, preferably 0.1 to 0.5 wt.%, for example 0.1 wt.%, 0.2 wt.%, 0.3 wt.%, 0.4 wt.%, 0.5 wt.%, 0.6 wt.%, 0.7 wt.%, 0.8 wt.%, 0.9 wt.% or 1 wt.%.
The nonaqueous electrolytic solution of the present invention, m 2-propyn-1-yl 1H-imidazole-1-carboxylic acid esters 0.1 to 2.0 wt.%, preferably 0.1 to 1.0 wt.%, for example 0.1 wt.%, 0.2 wt.%, 0.3 wt.%, 0.4 wt.%, 0.5 wt.%, 0.6 wt.%, 0.7 wt.%, 0.8 wt.%, 0.9 wt.%, 1 wt.%, 1.1 wt.%, 1.2 wt.%, 1.3 wt.%, 1.4 wt.%, 1.5 wt.%, 1.6 wt.%, 1.7 wt.%, 1.8 wt.%, 1.9 wt.% or 2 wt.%.
The nonaqueous electrolytic solution of the present invention, m Difluoroacetic acid ethyl ester 0.1 to 10.0 wt.%, preferably 0.1 to 6.0 wt.%, for example 0.1 wt.%, 0.2 wt.%, 0.3 wt.%, 0.4 wt.%, 0.5 wt.%, 0.6 wt.%, 0.7 wt.%, 0.8 wt.%, 0.9 wt.%, 1 wt.%, 1.1 wt.%, 1.2 wt.%, 1.3 wt.%, 1.4 wt.%, 1.5 wt.%, 1.6 wt.%, 1.7 wt.%, 1.8 wt.%, 1.9 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, 5 wt.%, 6 wt.%, 7 wt.%, 8 wt.%, 9 wt.% or 10 wt.%.
As mentioned above, the mass ratio m of cyanoethylsulfonylacetonitrile to 2-propyn-1-yl 1H-imidazole-1-carboxylate Cyanoethyl sulfonyl acetonitrile :m 2-propyn-1-yl 1H-imidazole-1-carboxylic acid esters The following relation is satisfied:
m cyanoethylsulfonyl acetonitrile :m 2-propyn-1-yl 1H-imidazole-1-carboxylic acid esters ＝1:(1～2)；
In particular, m Cyanoethylsulfonyl acetonitrile :m 2-propyn-1-yl 1H-imidazole-1-carboxylic acid esters May be 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9 or 1:2.
As mentioned above, the mass ratio m of cyanoethylsulfonylacetonitrile, 2-propyn-1-yl 1H-imidazole-1-carboxylate and ethyl difluoroacetate Cyanoethylsulfonylacetonitrile + 2-propyn-1-yl 1H-imidazole-1-carboxylic acid ester :m Difluoroacetic acid ethyl ester The following relation is satisfied:
m cyanoethylsulfonylacetonitrile + 2-propyn-1-yl 1H-imidazole-1-carboxylic acid ester :m Difluoroacetic acid ethyl ester ＝1:(2～4)；
In particular, m Cyanoethylsulfonylacetonitrile + 2-propyn-1-yl 1H-imidazole-1-carboxylic acid ester :m Difluoroacetic acid ethyl ester May be 1:2, 1:2.5, 1:3, 1:3.5 or 1: 4.
According to the nonaqueous electrolytic solution of the present invention, the nonaqueous organic solvent includes at least one of a cyclic carbonate and a linear carboxylate.
According to the nonaqueous electrolytic solution of the present invention, the cyclic carbonate includes at least one of ethylene carbonate, propylene carbonate, and fluoroethylene carbonate.
Preferably, the cyclic carbonate includes ethylene carbonate, propylene carbonate, and fluoroethylene carbonate.
According to the nonaqueous electrolytic solution of the present invention, the linear carboxylic acid ester includes at least one of ethyl propionate, propyl propionate, and propyl acetate.
Preferably, the linear carboxylic acid ester comprises ethyl propionate, propyl acetate.
According to the nonaqueous electrolytic solution of the present invention, the mass ratio m of the ethylene carbonate, the propylene carbonate and the fluorinated cyclic carbonate is Ethylene carbonate + propylene carbonate :m Fluoroethylene carbonate According to the relation:
m ethylene carbonate + propylene carbonate :m Fluoroethylene carbonate ＝1:(1～2)；
In particular, m Ethylene carbonate + propylene carbonate :m Fluoroethylene carbonate Can be 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9 or 1: 2;
wherein m is Ethylene carbonate + propylene carbonate Is ethylene carbonate and carbonic acidThe mass sum of the propylene ester accounts for the mass percentage of the total mass of the non-aqueous electrolyte; m is Fluoroethylene carbonate The mass percentage of the fluorinated cyclic carbonate accounts for the total mass of the non-aqueous electrolyte.
According to the nonaqueous electrolytic solution of the present invention, the electrolytic lithium salt is selected from one or more of the following compounds: lithium difluorophosphate, lithium hexafluorophosphate, lithium difluorooxalato borate, lithium tetrafluoroborate, lithium difluorooxalato phosphate, lithium bistrifluoromethanesulfonylimide.
According to the nonaqueous electrolytic solution of the present invention, the content of the electrolytic lithium salt is 14.0 to 17.0 wt%, for example, 14 wt%, 15 wt%, 16 wt%, or 17 wt% of the total mass of the nonaqueous electrolytic solution.
The invention also provides a battery which comprises the nonaqueous electrolyte.
According to the battery of the present invention, the battery is a lithium ion battery.
According to the battery of the invention, the battery further comprises a positive plate containing the positive active material, a negative plate containing the negative active material, and a separator.
According to the battery, the positive active material is one or more selected from layered lithium transition metal composite oxides, lithium manganate, lithium cobaltate and mixed ternary materials;
wherein the chemical formula of the layered lithium transition metal composite oxide is Li 1+x Ni y Co z M (1-y-z) Y 2 Wherein x is more than or equal to-0.1 and less than or equal to 1; y is more than or equal to 0 and less than or equal to 1, z is more than or equal to 0 and less than or equal to 1, and y + z is more than or equal to 0 and less than or equal to 1; wherein M is one or more of Mg, Zn, Ga, Ba, Al, Fe, Cr, Sn, V, Mn, Sc, Ti, Nb, Mo and Zr; y is one or more of O, F, P, S.
Preferably, the positive active material is LiCoO 2 Or LiCoO which is doped and coated by one or more elements of Al, Mg, Ti and Zr 2 。
According to the battery of the invention, the negative active material is selected from one or more of carbon-based materials, silicon-based materials, tin-based materials or their corresponding alloy materials.
Preferably, the negative active material is selected from a graphite material, a graphite composite material containing 1 to 10 wt% of silica, or a graphite composite material containing 1 to 10 wt% of silicon.
According to the battery, the isolation film comprises a substrate and a composite layer coated on the substrate and comprising inorganic particles and polymers, and the thickness of the composite layer is 1-5 microns.
According to the battery of the present invention, the inorganic particles are titanium oxide, and the polymer is a polyvinylidene fluoride-hexafluoropropylene copolymer.
According to the battery of the present invention, the charge cut-off voltage of the battery is 4.45V or more.
The invention has the beneficial effects that:
the invention provides a non-aqueous electrolyte and a battery comprising the same, wherein cyanoethylsulfonyl acetonitrile, 2-propyne-1-yl 1H-imidazole-1-carboxylate and ethyl difluoroacetate are used as electrolyte functional additives, the three functional additives can act on a positive interface and a negative interface in a synergistic manner to form a stable interface film, so that the interior of the battery is always kept in a stable state in the charge-discharge cycle process, and on the basis, the electrode/electrolyte interface with high stability can effectively inhibit the side reaction of the electrolyte in the charge-discharge cycle process of the battery, improve the cycle stability of the battery, and a battery comprising the nonaqueous electrolytic solution can maintain a stable internal state under overcharge conditions thanks to the highly stable interfacial film, the cycle performance of the battery can be obviously improved, and the prepared battery has excellent overcharge resistance.
Detailed Description
The present invention will be described in further detail with reference to specific examples. It is to be understood that the following examples are only illustrative and explanatory of the present invention and should not be construed as limiting the scope of the present invention. It is intended that all modifications and equivalents of the technical aspects of the present invention be included within the scope of the present invention without departing from the spirit and scope of the technical aspects of the present invention.
The following table gives the english abbreviations corresponding to the solvents used in the examples of the present application:
| name of solvent | English abbreviation |
| Ethylene carbonate | EC |
| Propylene carbonate | PC |
| Fluoroethylene carbonate | FEC |
Examples 1 to 14 and comparative examples 1 to 9
(1) Preparation of positive plate
Mixing a positive electrode active material Lithium Cobaltate (LCO), a binder polyvinylidene fluoride (PVDF) and a conductive agent acetylene black according to a mass ratio of 97:1.5:1.5, adding N-methyl pyrrolidone (NMP), and stirring under the action of a vacuum stirrer until a mixed system becomes a uniform and fluid positive electrode slurry; uniformly coating the positive electrode slurry on a current collector aluminum foil; baking the coated aluminum foil in 5 sections of baking ovens with different temperature gradients, drying the aluminum foil in a baking oven at 120 ℃ for 8 hours, and rolling and cutting to obtain the required positive plate.
(2) Preparation of negative plate
Mixing a negative electrode active material graphite, a thickening agent sodium carboxymethyl cellulose (CMC-Na), a binder styrene butadiene rubber and a conductive agent acetylene black according to a mass ratio of 97:1:1:1, adding deionized water, and obtaining negative electrode slurry under the action of a vacuum stirrer; uniformly coating the negative electrode slurry on the high-strength carbon-coated copper foil to obtain a pole piece; and (3) airing the obtained pole piece at room temperature, transferring the pole piece to an oven at 80 ℃ for drying for 10h, and then rolling and slitting to obtain the negative pole piece.
(3) Preparation of electrolyte
In a glove box filled with inert gas (argon) (H) 2 O＜0.1ppm，O 2 < 0.1ppm), ethylene carbonate and propyl propionate in a mass ratio of 1:3 were uniformly mixed, and then sufficiently dried lithium hexafluorophosphate (LiPF) was rapidly added thereto 6 ) Control of LiPF 6 The mass percent of the mixture in the non-aqueous electrolyte is 14.5 wt.%, the mixture is uniformly stirred, functional additives (the content of specific components is shown in table 1) are added, the mixture is uniformly stirred again, and the non-aqueous electrolyte is obtained after the water and free acid are detected to be qualified.
(4) Preparation of the separator
An 8-micron-thick coating (the coating comprises titanium oxide and polyvinylidene fluoride-hexafluoropropylene copolymer in a mass ratio of 1: 1) polyethylene isolating film is selected.
(5) Preparation of lithium ion battery
Stacking the prepared positive plate, the prepared isolating membrane and the prepared negative plate in sequence to ensure that the isolating membrane is positioned between the positive plate and the negative plate to play an isolating role, and then obtaining a naked battery cell without liquid injection through winding; and placing the bare cell in an outer packaging foil, injecting the prepared corresponding electrolyte into the dried bare cell, and performing vacuum packaging, standing, formation, shaping, sorting and other processes to obtain the corresponding lithium ion battery.
And (3) performance testing:
(1) and (3) testing the 25 ℃ cycle life of the lithium ion battery:
and (3) placing the battery obtained correspondingly in a constant temperature environment at 25 ℃ to perform charge-discharge test at a rate of 1C/1C, wherein the cut-off voltage range is 3.0V-4.48V, the charge-discharge cycle is performed for 1000 times, and the cycle discharge capacity is recorded and divided by the discharge capacity of the first cycle to obtain the cycle capacity retention rate.
(2) And (3) testing the overcharge resistance of the lithium ion battery at 25 ℃ under 3C-5V:
and (3) carrying out constant current charging to 5V at the rate of 3C at the temperature of 25 ℃, keeping the constant voltage of 5V for 8h, and observing whether the battery explodes or fires. If the battery is not exploded or ignited, the battery is judged as PASS, otherwise, the battery is FAIL.
TABLE 1 information on nonaqueous electrolytes of lithium ion batteries of examples 1 to 14 and comparative examples 1 to 9
Table 2 results of performance test of lithium ion batteries of examples 1 to 14 and comparative examples 1 to 9
As shown in the results of table 2, the use of the base electrolyte in comparative example 1 exhibited poor cycle life and failure occurred on the overcharge performance test. In comparative examples 2 to 5, when the first additive, the second additive and the third additive were not simultaneously added, the cycle life and the overcharge prevention performance of the battery could not be effectively improved. In comparative examples 6 to 9, the three additives were added simultaneously, but the specific ratio as set forth in the present application was not satisfied, and it was still difficult to obtain a significant effect on the improvement of the cycle life and the overcharge prevention performance of the battery. In summary, the inventors speculate that: on one hand, the first additive, the second additive and the third additive are simultaneously used as electrode interface film forming additives, and the composition and the structure of a formed interface film can be optimized only by meeting a certain proportional relation, so that the effect of obviously improving the performance of the battery is realized; on the other hand, the three components are used as functional additives with film forming reactivity, the respective reactions have certain influence on each other, and the reactivity has a decisive influence on the final film forming effect. Therefore, in the embodiment of the present application, when the nonaqueous electrolytic solution contains the first additive, the second additive, and the third additive at the same time, and the following specific ratio relationship is satisfied: m is First additive :m Second additive ＝1:(1～2)；m First additive + second additive :m Third additive The cycle life and the overcharge prevention performance of the lithium ion battery are obviously improved as 1 to 4, and the data results of the examples 1 to 14 in the table 2 show.
Further, the inventors found that when the cyclic carbonate in the nonaqueous electrolytic solution is optimized, the synergistic film-forming action of the first additive, the second additive, and the third additive can be made more effective in improving the cycle life and overcharge performance of the lithium ion battery, and thus proposed the following examples.
Examples 15 to 23
The other preparation process is the same as example 1 except that (3) the electrolyte is prepared as follows:
in a glove box filled with inert gas (argon) (H) 2 O＜0.1ppm，O 2 < 0.1ppm), a cyclic carbonate (specific component contents shown in Table 3) and propyl propionate were mixed in a mass ratio of 1:3, and then sufficiently dried lithium hexafluorophosphate (LiPF) was rapidly added thereto 6 ) Control of LiPF 6 The mass percent of the mixture in the non-aqueous electrolyte is 14.5 wt.%, the mixture is uniformly stirred, functional additives (0.5% of cyanoethylsulfonyl acetonitrile, 0.8% of 2-propyn-1-yl 1H-imidazole-1-carboxylic ester and 5% of ethyl difluoroacetate) are added, the mixture is uniformly stirred again, and the non-aqueous electrolyte is obtained after the water and free acid detection is qualified.
TABLE 3 solvent composition for non-aqueous electrolyte solutions of lithium ion batteries of examples 15-23
As can be seen from table 3, the composition of the solvent in the nonaqueous electrolyte solution is particularly important for the performance of the lithium ion battery, and particularly, the selection of the cyclic carbonate organic solvent plays a crucial role in the formation of the SEI film. In the present invention, by adjusting the components in the cyclic carbonate to satisfy the following ratio relationship: m is Ethylene carbonate + propylene carbonate :m Fluoroethylene carbonate (1-2) that can preferably elevate the electrode/electrolyte interfaceStability, thereby more remarkably improving the cycle life and overcharge resistance of the lithium ion battery.
In conclusion, the nonaqueous electrolyte solution scheme and the battery using the nonaqueous electrolyte solution scheme provided by the invention have excellent charging performance, realize improved cycle life and show extremely high application value. The above is a specific description of possible embodiments of the invention, but does not limit the scope of the invention.
Claims (11)
1. A nonaqueous electrolyte solution comprising a nonaqueous organic solvent, an electrolytic lithium salt, and a functional additive; the functional additive comprises a first additive, a second additive and a third additive, wherein the first additive is cyanoethylsulfonyl acetonitrile, the second additive is 2-propyn-1-yl 1H-imidazole-1-carboxylic ester, and the third additive is ethyl difluoroacetate;
the mass ratio m of the cyanoethylsulfonyl acetonitrile to the 2-propyne-1-yl 1H-imidazole-1-carboxylic ester to the ethyl difluoroacetate Cyanoethylsulfonylacetonitrile + 2-propyn-1-yl 1H-imidazole-1-carboxylic acid ester :m Difluoroacetic acid ethyl ester The following relation is satisfied:
m cyanoethylsulfonylacetonitrile + 2-propyn-1-yl 1H-imidazole-1-carboxylic acid ester :m Difluoroacetic acid ethyl ester =1:(2~4)；
The mass ratio m of the cyanoethylsulfonyl acetonitrile to the 2-propyn-1-yl 1H-imidazole-1-carboxylic ester Cyanoethyl sulfonyl acetonitrile :m 2-propyn-1-yl 1H-imidazole-1-carboxylic acid esters The following relationships are satisfied:
m cyanoethyl sulfonyl acetonitrile :m 2-propyn-1-yl 1H-imidazole-1-carboxylic acid esters =1:(1~2)。
2. The nonaqueous electrolytic solution of claim 1, wherein m is Cyanoethyl sulfonyl acetonitrile 0.1 to 1.0 wt%.
3. The nonaqueous electrolytic solution of claim 2, wherein m is Cyanoethylsulfonyl acetonitrile 0.1 to 0.5 wt%.
4. The nonaqueous electrolytic solution of claim 1, wherein m is 2-propyn-1-yl 1H-imidazole-1-carboxylic acid esters 0.1 to 2.0 wt%.
5. The nonaqueous electrolytic solution of claim 4, wherein m is 2-propyn-1-yl 1H-imidazole-1-carboxylic acid esters 0.1 to 1.0 wt%.
6. The nonaqueous electrolytic solution of claim 1, wherein m is Difluoroacetic acid ethyl ester 0.1 to 10.0 wt%.
7. The nonaqueous electrolytic solution of claim 6, wherein m is Difluoroacetic acid ethyl ester 0.1 to 6.0 wt%.
8. The nonaqueous electrolytic solution of any one of claims 1 to 7, wherein the nonaqueous organic solvent includes at least one of a cyclic carbonate and a linear carboxylate; the cyclic carbonate comprises at least one of ethylene carbonate, propylene carbonate and fluoroethylene carbonate;
the linear carboxylic ester comprises at least one of ethyl propionate, propyl propionate and propyl acetate.
9. The nonaqueous electrolytic solution of claim 8, wherein the cyclic carbonate includes ethylene carbonate, propylene carbonate, and fluoroethylene carbonate; the linear carboxylic ester comprises ethyl propionate, propyl propionate and propyl acetate.
10. The nonaqueous electrolytic solution of claim 8, wherein the mass ratio m of the ethylene carbonate, the propylene carbonate and the fluorocyclic carbonate is Ethylene carbonate + propylene carbonate :m Fluoroethylene carbonate The following relation is satisfied:
m ethylene carbonate + propylene carbonate :m Fluoroethylene carbonate =1:(1~2)。
11. A battery comprising the nonaqueous electrolytic solution of any one of claims 1 to 10.
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| WO2019243351A1 (en) * | 2018-06-18 | 2019-12-26 | Centre National De La Recherche Scientifique | New electrolyte composition for sodium-ion battery |
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