CN114094190B - Electrolyte and preparation method and application thereof - Google Patents
Electrolyte and preparation method and application thereof Download PDFInfo
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- CN114094190B CN114094190B CN202111396428.9A CN202111396428A CN114094190B CN 114094190 B CN114094190 B CN 114094190B CN 202111396428 A CN202111396428 A CN 202111396428A CN 114094190 B CN114094190 B CN 114094190B
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- electrolyte
- lithium
- carbonate
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- additive
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- 239000003792 electrolyte Substances 0.000 title claims abstract description 126
- 238000002360 preparation method Methods 0.000 title abstract description 30
- -1 sultone compound Chemical class 0.000 claims abstract description 64
- 239000000654 additive Substances 0.000 claims abstract description 32
- 239000003960 organic solvent Substances 0.000 claims abstract description 32
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 claims abstract description 30
- 230000000996 additive effect Effects 0.000 claims abstract description 30
- 229910001416 lithium ion Inorganic materials 0.000 claims abstract description 30
- 238000000034 method Methods 0.000 claims abstract description 20
- 229910003002 lithium salt Inorganic materials 0.000 claims abstract description 19
- 159000000002 lithium salts Chemical class 0.000 claims abstract description 19
- VAYTZRYEBVHVLE-UHFFFAOYSA-N 1,3-dioxol-2-one Chemical compound O=C1OC=CO1 VAYTZRYEBVHVLE-UHFFFAOYSA-N 0.000 claims description 27
- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 claims description 18
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 claims description 18
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 claims description 18
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 claims description 18
- IGILRSKEFZLPKG-UHFFFAOYSA-M lithium;difluorophosphinate Chemical compound [Li+].[O-]P(F)(F)=O IGILRSKEFZLPKG-UHFFFAOYSA-M 0.000 claims description 17
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 claims description 9
- 125000000217 alkyl group Chemical group 0.000 claims description 9
- 239000001257 hydrogen Substances 0.000 claims description 9
- 229910052739 hydrogen Inorganic materials 0.000 claims description 9
- 239000007773 negative electrode material Substances 0.000 claims description 9
- 150000002431 hydrogen Chemical class 0.000 claims description 8
- 239000006258 conductive agent Substances 0.000 claims description 7
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 claims description 7
- 239000000126 substance Substances 0.000 claims description 7
- 239000011883 electrode binding agent Substances 0.000 claims description 6
- FKRCODPIKNYEAC-UHFFFAOYSA-N ethyl propionate Chemical compound CCOC(=O)CC FKRCODPIKNYEAC-UHFFFAOYSA-N 0.000 claims description 6
- 239000007774 positive electrode material Substances 0.000 claims description 6
- 239000008151 electrolyte solution Substances 0.000 claims description 5
- 229910052736 halogen Inorganic materials 0.000 claims description 5
- 150000002367 halogens Chemical class 0.000 claims description 5
- 239000000463 material Substances 0.000 claims description 5
- 238000002156 mixing Methods 0.000 claims description 5
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 claims description 5
- CDUWJQGFRQTJHB-UHFFFAOYSA-N 1,3,2-dioxathiole 2,2-dioxide Chemical compound O=S1(=O)OC=CO1 CDUWJQGFRQTJHB-UHFFFAOYSA-N 0.000 claims description 4
- 125000006374 C2-C10 alkenyl group Chemical group 0.000 claims description 4
- 125000005865 C2-C10alkynyl group Chemical group 0.000 claims description 4
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 claims description 4
- SJHAYVFVKRXMKG-UHFFFAOYSA-N 4-methyl-1,3,2-dioxathiolane 2-oxide Chemical compound CC1COS(=O)O1 SJHAYVFVKRXMKG-UHFFFAOYSA-N 0.000 claims description 3
- NVJBFARDFTXOTO-UHFFFAOYSA-N diethyl sulfite Chemical compound CCOS(=O)OCC NVJBFARDFTXOTO-UHFFFAOYSA-N 0.000 claims description 3
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 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
- VDVLPSWVDYJFRW-UHFFFAOYSA-N lithium;bis(fluorosulfonyl)azanide Chemical compound [Li+].FS(=O)(=O)[N-]S(F)(=O)=O VDVLPSWVDYJFRW-UHFFFAOYSA-N 0.000 claims description 3
- FSSPGSAQUIYDCN-UHFFFAOYSA-N 1,3-Propane sultone Chemical compound O=S1(=O)CCCO1 FSSPGSAQUIYDCN-UHFFFAOYSA-N 0.000 claims description 2
- 125000001797 benzyl group Chemical group [H]C1=C([H])C([H])=C(C([H])=C1[H])C([H])([H])* 0.000 claims description 2
- 229910001496 lithium tetrafluoroborate Inorganic materials 0.000 claims description 2
- 229920006395 saturated elastomer Polymers 0.000 claims description 2
- SYRDSFGUUQPYOB-UHFFFAOYSA-N [Li+].[Li+].[Li+].[O-]B([O-])[O-].FC(=O)C(F)=O Chemical compound [Li+].[Li+].[Li+].[O-]B([O-])[O-].FC(=O)C(F)=O SYRDSFGUUQPYOB-UHFFFAOYSA-N 0.000 claims 1
- DEUISMFZZMAAOJ-UHFFFAOYSA-N lithium dihydrogen borate oxalic acid Chemical compound B([O-])(O)O.C(C(=O)O)(=O)O.C(C(=O)O)(=O)O.[Li+] DEUISMFZZMAAOJ-UHFFFAOYSA-N 0.000 claims 1
- 230000014759 maintenance of location Effects 0.000 abstract description 14
- 230000008569 process Effects 0.000 abstract description 12
- 238000007599 discharging Methods 0.000 abstract description 8
- 238000007086 side reaction Methods 0.000 abstract description 6
- 230000006866 deterioration Effects 0.000 abstract description 5
- 230000002035 prolonged effect Effects 0.000 abstract description 4
- 238000013461 design Methods 0.000 abstract description 3
- 238000003756 stirring Methods 0.000 description 14
- 230000000052 comparative effect Effects 0.000 description 12
- 239000012046 mixed solvent Substances 0.000 description 10
- 238000012360 testing method Methods 0.000 description 7
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 6
- 239000003292 glue Substances 0.000 description 6
- 229910052744 lithium Inorganic materials 0.000 description 6
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 5
- 239000000243 solution Substances 0.000 description 5
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 4
- 239000002002 slurry Substances 0.000 description 4
- 239000002000 Electrolyte additive Substances 0.000 description 3
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 3
- RWRDLPDLKQPQOW-UHFFFAOYSA-N Pyrrolidine Chemical group C1CCNC1 RWRDLPDLKQPQOW-UHFFFAOYSA-N 0.000 description 3
- 239000002041 carbon nanotube Substances 0.000 description 3
- 229910021393 carbon nanotube Inorganic materials 0.000 description 3
- 230000008859 change Effects 0.000 description 3
- 229910010272 inorganic material Inorganic materials 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 238000011160 research Methods 0.000 description 3
- 229920003048 styrene butadiene rubber Polymers 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- SBLRHMKNNHXPHG-UHFFFAOYSA-N 4-fluoro-1,3-dioxolan-2-one Chemical compound FC1COC(=O)O1 SBLRHMKNNHXPHG-UHFFFAOYSA-N 0.000 description 2
- BTBUEUYNUDRHOZ-UHFFFAOYSA-N Borate Chemical compound [O-]B([O-])[O-] BTBUEUYNUDRHOZ-UHFFFAOYSA-N 0.000 description 2
- KAKZBPTYRLMSJV-UHFFFAOYSA-N Butadiene Chemical compound C=CC=C KAKZBPTYRLMSJV-UHFFFAOYSA-N 0.000 description 2
- 239000002174 Styrene-butadiene Substances 0.000 description 2
- 125000003342 alkenyl group Chemical group 0.000 description 2
- 125000000304 alkynyl group Chemical group 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 238000013329 compounding Methods 0.000 description 2
- 238000005336 cracking Methods 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- BBLSYMNDKUHQAG-UHFFFAOYSA-L dilithium;sulfite Chemical compound [Li+].[Li+].[O-]S([O-])=O BBLSYMNDKUHQAG-UHFFFAOYSA-L 0.000 description 2
- 239000010439 graphite Substances 0.000 description 2
- 229910002804 graphite Inorganic materials 0.000 description 2
- GLNWILHOFOBOFD-UHFFFAOYSA-N lithium sulfide Chemical compound [Li+].[Li+].[S-2] GLNWILHOFOBOFD-UHFFFAOYSA-N 0.000 description 2
- PYLWMHQQBFSUBP-UHFFFAOYSA-N monofluorobenzene Chemical compound FC1=CC=CC=C1 PYLWMHQQBFSUBP-UHFFFAOYSA-N 0.000 description 2
- 239000011255 nonaqueous electrolyte Substances 0.000 description 2
- 238000011056 performance test Methods 0.000 description 2
- 125000003386 piperidinyl group Chemical group 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 238000007873 sieving Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 125000002153 sulfur containing inorganic group Chemical group 0.000 description 2
- GWAOOGWHPITOEY-UHFFFAOYSA-N 1,5,2,4-dioxadithiane 2,2,4,4-tetraoxide Chemical compound O=S1(=O)CS(=O)(=O)OCO1 GWAOOGWHPITOEY-UHFFFAOYSA-N 0.000 description 1
- 125000004973 1-butenyl group Chemical group C(=CCC)* 0.000 description 1
- 125000004974 2-butenyl group Chemical group C(C=CC)* 0.000 description 1
- 125000003903 2-propenyl group Chemical group [H]C([*])([H])C([H])=C([H])[H] 0.000 description 1
- 125000001494 2-propynyl group Chemical group [H]C#CC([H])([H])* 0.000 description 1
- 125000004975 3-butenyl group Chemical group C(CC=C)* 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910013075 LiBF Inorganic materials 0.000 description 1
- 229910010707 LiFePO 4 Inorganic materials 0.000 description 1
- 229910013872 LiPF Inorganic materials 0.000 description 1
- 101150058243 Lipf gene Proteins 0.000 description 1
- 239000002033 PVDF binder Substances 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
- 230000002378 acidificating effect Effects 0.000 description 1
- HSFWRNGVRCDJHI-UHFFFAOYSA-N alpha-acetylene Natural products C#C HSFWRNGVRCDJHI-UHFFFAOYSA-N 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 125000003277 amino group Chemical group 0.000 description 1
- 239000003125 aqueous solvent Substances 0.000 description 1
- 125000002393 azetidinyl group Chemical group 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 125000000480 butynyl group Chemical group [*]C#CC([H])([H])C([H])([H])[H] 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000003575 carbonaceous material Substances 0.000 description 1
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 1
- 239000001768 carboxy methyl cellulose Substances 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- XTHPWXDJESJLNJ-UHFFFAOYSA-M chlorosulfate Chemical group [O-]S(Cl)(=O)=O XTHPWXDJESJLNJ-UHFFFAOYSA-M 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000001351 cycling effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 239000008367 deionised water Substances 0.000 description 1
- 229910021641 deionized water Inorganic materials 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000007580 dry-mixing Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 125000002534 ethynyl group Chemical group [H]C#C* 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 206010016766 flatulence Diseases 0.000 description 1
- 125000000524 functional group Chemical group 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 150000002484 inorganic compounds Chemical class 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 125000000959 isobutyl group Chemical group [H]C([H])([H])C([H])(C([H])([H])[H])C([H])([H])* 0.000 description 1
- 125000001972 isopentyl group Chemical group [H]C([H])([H])C([H])(C([H])([H])[H])C([H])([H])C([H])([H])* 0.000 description 1
- 125000001449 isopropyl group Chemical group [H]C([H])([H])C([H])(*)C([H])([H])[H] 0.000 description 1
- 229910052808 lithium carbonate Inorganic materials 0.000 description 1
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 1
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 1
- 125000001570 methylene group Chemical group [H]C([H])([*:1])[*:2] 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 125000004108 n-butyl group Chemical group [H]C([H])([H])C([H])([H])C([H])([H])C([H])([H])* 0.000 description 1
- 125000003136 n-heptyl group Chemical group [H]C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])* 0.000 description 1
- 125000001280 n-hexyl group Chemical group C(CCCCC)* 0.000 description 1
- 125000000740 n-pentyl group Chemical group [H]C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])* 0.000 description 1
- 125000004123 n-propyl group Chemical group [H]C([H])([H])C([H])([H])C([H])([H])* 0.000 description 1
- 125000001971 neopentyl group Chemical group [H]C([*])([H])C(C([H])([H])[H])(C([H])([H])[H])C([H])([H])[H] 0.000 description 1
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 description 1
- MHYFEEDKONKGEB-UHFFFAOYSA-N oxathiane 2,2-dioxide Chemical compound O=S1(=O)CCCCO1 MHYFEEDKONKGEB-UHFFFAOYSA-N 0.000 description 1
- 125000002255 pentenyl group Chemical group C(=CCCC)* 0.000 description 1
- 125000005981 pentynyl group Chemical group 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 229920006254 polymer film Polymers 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 1
- 239000004810 polytetrafluoroethylene Substances 0.000 description 1
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 1
- 125000004368 propenyl group Chemical group C(=CC)* 0.000 description 1
- 125000002568 propynyl group Chemical group [*]C#CC([H])([H])[H] 0.000 description 1
- 150000003254 radicals Chemical class 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000006479 redox reaction Methods 0.000 description 1
- 230000008439 repair process Effects 0.000 description 1
- 238000007142 ring opening reaction Methods 0.000 description 1
- 238000007790 scraping Methods 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
- 238000003860 storage Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 125000000999 tert-butyl group Chemical group [H]C([H])([H])C(*)(C([H])([H])[H])C([H])([H])[H] 0.000 description 1
- 125000003554 tetrahydropyrrolyl group Chemical group 0.000 description 1
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 1
- 229920002554 vinyl polymer Polymers 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
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Inorganic Chemistry (AREA)
- Secondary Cells (AREA)
Abstract
The invention provides an electrolyte, a preparation method and an application thereof, wherein the electrolyte comprises a lithium salt, an additive and an organic solvent; the additive comprises a sultone compound with a structure shown in a formula I. Through the design of the components, particularly, the sultone compound with a specific structure is used as an additive, so that a compact, stable and elastic SEI film is formed in the charging and discharging processes of the battery, the lithium ion conductivity of the SEI film is improved, the impedance can be effectively reduced, the occurrence of side reactions is reduced, the consumption and the deterioration of the electrolyte in the using process are reduced, the internal resistance of the electrolyte is reduced, the capacity retention rate is high, the normal-temperature and high-temperature cycle performance of the battery is obviously improved, and the service life of the battery is prolonged.
Description
Technical Field
The invention belongs to the technical field of lithium ion batteries, and particularly relates to an electrolyte and a preparation method and application thereof.
Background
With the increasing energy awareness of the public society, the development and efficient utilization of energy are becoming global concerns, and various battery systems are in the process of being operated to meet the increasing demands of electric vehicles and large-scale energy storage. In the portable electronic devices which are concerned at present, the lithium ion battery is preferred due to the advantages of high energy, high density, flexible and light design, longer service life than the similar batteries and the like, but the insufficient endurance mileage is still one of the key problems restricting the rapid development of the lithium battery industry. In order to improve the performance of the lithium ion battery, a small amount of additive is usually added to the electrolyte solution, so that an organic insoluble and stable Solid Electrolyte Interface (SEI) film is preferentially formed on the surface of the negative electrode, and the negative electrode material can be prevented from directly contacting with the electrolyte solution to generate side reactions, thereby effectively improving the cycle performance of the lithium battery.
Currently, many researches are focused on electrolyte additives and electrolyte performance researches, for example, CN108666619A discloses an electrolyte, which comprises lithium salt, electrolyte solvent and additives, wherein the additives are olefin compounds and derivatives thereof, which have a structure similar to butadiene, and double bond carbon is connected with halogen, the reduction decomposition potential is higher than that of carbonate electrolyte solvent, and a protective film can be preferentially formed on the surface of a negative electrode to prevent further reduction decomposition of the electrolyte; the protective film is a polymer film, has elasticity, can ensure the volume change of the negative electrode in the lithium releasing and embedding process without cracking, prevents the redox reaction of the electrolyte at the negative electrode, and protects the electrolyte from being excessively consumed, thereby improving the performance of the negative electrode lithium battery. CN105633460A discloses a lithium ion secondary battery and an electrolyte thereof, wherein the electrolyte comprises an organic solvent, a lithium salt and an additive, the additive is a glycidyl ester compound, which can improve the ion conductivity of an SEI film, and the formed SEI film has lower impedance, thus improving the high-temperature storage performance and cycle performance of the lithium ion secondary battery. CN107887645A discloses a lithium ion battery non-aqueous electrolyte and a lithium ion battery, wherein the lithium ion battery non-aqueous electrolyte comprises a lithium salt, a non-aqueous solvent and an additive, and the additive is chlorosulfonate; the battery prepared from the electrolyte has low flatulence degree, and simultaneously shows good cycle performance and rate performance. Besides, the electrolyte additives commonly used in the industry at present include Vinylene Carbonate (VC), fluoroethylene carbonate (FEC), vinylene carbonate (VEC), fluorobenzene (FB), and the like.
Although the electrolyte additive in the prior art improves the cycle performance of the battery from the aspects of film forming property, impedance reduction and the like of the SEI film, acidic substances (such as hydrofluoric acid) generated by side reactions of the electrolyte in the middle and later periods of normal-temperature cycle and high-temperature cycle still damage the structure of the SEI film, and the repair of the SEI film also accelerates the consumption of the electrolyte, and causes the phenomena of cycle performance deterioration and the like.
Therefore, it is a research focus in the field to develop an electrolyte with excellent performance to improve the normal temperature and high temperature cycle performance of a lithium ion battery.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide the electrolyte and the preparation method and application thereof, and the electrolyte can effectively reduce the impedance, improve the normal-temperature and high-temperature cycle performance of the battery and improve the capacity retention rate by adopting the additive with a specific structure and compounding the additive with other components.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the present invention provides an electrolyte comprising a lithium salt, an additive, and an organic solvent; the additive comprises a sultone compound with a structure shown in a formula I:
in the formula I, R 1 、R 2 Each independently selected from any one of C1-C10 straight chain or branched chain alkyl, C2-C10 alkenyl, C2-C10 alkynyl or phenyl.
In the formula I, the compound is shown in the specification,
represents R 1 And R 2 Not linked or linked by chemical bonds to form a ring; the ring is a C2-C6 saturated azacyclic ring.
In the formula I, A is CH or N.
In the formula I, R 3 Selected from hydrogen, C1-C10 straight chain or branched chain alkyl, C2-C10 alkenyl, C2-C10 alkynyl or
Any one of the above; wherein, represents the linking site of the group, m represents the number of methylene groups, is an integer of 0 to 3, and may be, for example, 0, 1, 2 or 3; when n is 0, it means that the benzene ring is bonded to A by a single bond.
In the formula I, R 4 Is selected from any one of hydrogen, halogen and C1-C10 straight chain or branched chain alkyl.
The electrolyte provided by the invention comprises a sultone compound with a structure shown in formula I as an additive, and the additive is compounded with other components, so that the additive can be rapidly decomposed and a compact and stable SEI film is formed on the surface of a negative electrode in the charge and discharge processes of a lithium ion battery, wherein the electrolyte comprises a sulfur-containing inorganic compound (for example, a sulfur-containing inorganic compound)Such as lithium sulfide, lithium sulfite, etc.; the sultone bond in the sultone compound with the structure shown in the formula I is broken to form a ring-opening cyclic anionic free radical and-SO 2 Radical or-SO 3 A group which generates lithium sulfite or further reduces to generate lithium sulfide), and the existence of the inorganic compound can improve the overall lithium ion conductivity of the SEI film; meanwhile, the additive can preferentially carry out electrochemical polymerization on the surface of the cathode, so that the SEI film has excellent elasticity, can adapt to the volume change of carbon materials in the charge and discharge processes to avoid cracking as far as possible, effectively isolates the cathode from the electrolyte, avoids direct contact of the cathode and the electrolyte and reduces the occurrence of side reactions. Moreover, an SEI film formed on the surface of the negative electrode by the additive also contains a basic functional group (amino group), so that hydrofluoric acid generated in a circulation process, particularly a high-temperature circulation process can be effectively captured, the consumption and the deterioration of an electrolyte in a use process are reduced, the circulation performance of the battery is improved, the capacity retention rate is improved, and the service life of the battery is prolonged.
In the present invention, the C1 to C10 linear or branched alkyl groups may be C1, C2, C3, C4, C5, C6, C7, C8, C9, C10 linear or branched alkyl groups, which exemplarily include but are not limited to: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl or n-decyl, and the like.
The C2 to C10 alkenyl groups may each be a C2, C3, C4, C5, C6, C7, C8, C9, C10 straight or branched alkenyl group including at least one-C = C-bond, including, by way of example but not limitation: vinyl, propenyl, allyl, 1-butenyl, 2-butenyl, 3-butenyl, pentenyl, or the like.
The C2 to C10 alkynyl groups may each be a C2, C3, C4, C5, C6, C7, C8, C9, C10 straight or branched chain alkynyl group including at least one-C ≡ C-bond, including, by way of example but not limited to: ethynyl, propynyl, propargyl, butynyl, pentynyl, and the like.
In the present invention, R is 1 And R 2 Not linked or linked by chemical bonds to form a ring; when R is 1 And R 2 When the ring is linked by a chemical bond, it forms a C2-C6 saturated nitrogen heterocycle with N, for example a saturated nitrogen heterocycle that may be C2, C3, C4, C5, or C6, including, but not limited to: a piperidine ring, a tetrahydropyrrole ring, or an azetidine ring, etc.
Preferably, said R is 1 、R 2 Each independently being methyl, ethyl or phenyl.
Said R is 1 And R 2 Are not connected or connected into C4-C5 saturated nitrogen heterocycles (piperidine ring or tetrahydropyrrole ring) through chemical bonds.
Preferably, said R is 3 Selected from hydrogen, methyl or benzyl.
Preferably, said R is 4 Selected from hydrogen, halogen or methyl, more preferably hydrogen or chlorine.
Preferably, the sultone compound has a structure as shown in any one of formula II, formula III, formula IV, formula V, or formula VI:
preferably, the content of the sultone compound in the electrolyte is 0.1 to 1.0% by mass, for example, 0.15%, 0.2%, 0.25%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 0.95%, and specific values therebetween are not exhaustive, and for brevity and conciseness, the present invention does not include the specific values included in the range, and more preferably 0.3 to 0.8%.
As a preferred technical scheme of the invention, the mass percentage content of the sultone compound in the electrolyte is 0.1-1%, and more preferably 0.3-0.8%; if the content of the sultone compound in the electrolyte is too low, the formation and the performance of an SEI film can be influenced, so that the impedance of the electrolyte cannot be effectively reduced, and the cycle performance of the battery is reduced; if the content of the sultone compound in the electrolyte is too high, not only is no further improvement effect achieved, but also an SEI film is too thick, and the internal resistance of the battery is increased.
Preferably, the amount of the lithium salt in the electrolyte is 10 to 20% by mass, for example, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, 15%, 16%, 17%, 18%, 19% or 19.5%, and the specific values therebetween are not exhaustive, and for brevity and conciseness, the invention does not include the specific values included in the range, and more preferably 12 to 16%.
In the present invention, the lithium salt is a lithium salt commonly used in the art, and includes an inorganic lithium salt and/or an organic lithium salt.
Preferably, the lithium salt is selected from lithium hexafluorophosphate (LiPF) 6 ) Lithium perchlorate (LiClO) 4 ) Lithium tetrafluoroborate (LiBF) 4 ) Lithium difluorophosphate (LiPO) 2 F 2 ) Any one or a combination of at least two of lithium bis (oxalato) borate (LiBOB), lithium difluoro (oxalato) borate (LiODFB), or lithium bis (fluorosulfonyl) imide (LiFSI).
Preferably, the lithium salt comprises lithium hexafluorophosphate and optionally lithium difluorophosphate.
Preferably, the electrolyte solution contains 12 to 14% by mass of lithium hexafluorophosphate, for example, 12.2%, 12.5%, 12.8%, 13%, 13.2%, 13.5% or 13.8%, and the specific values therebetween are not exhaustive, for reasons of brevity and simplicity.
Preferably, the electrolyte contains lithium difluorophosphate in an amount of 0.5 to 2% by mass, for example, 0.6%, 0.8%, 1%, 1.1%, 1.3%, 1.5%, 1.7% or 1.9%, and specific values therebetween, for reasons of brevity and clarity, the invention is not intended to be exhaustive of the specific values included in the ranges.
Preferably, the additive also comprises vinylene sulfate and/or Vinylene Carbonate (VC), and more preferably vinylene carbonate.
Preferably, the electrolyte contains 0.5 to 4% by mass of vinylene sulfate, for example 0.6%, 0.8%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5% or 3.8%, and the specific values therebetween are not exhaustive, but for reasons of brevity and clarity.
Preferably, the content of vinylene carbonate in the electrolyte is 0.5-4% by mass, for example, 0.6%, 0.8%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5% or 3.8%, and specific values therebetween are not exhaustive, but rather for reasons of brevity and clarity.
As a preferred technical scheme of the invention, the additive comprises a sultone compound with a structure shown in formula I and Vinylene Carbonate (VC), and the two are compounded, so that a more compact and stable SEI film is formed, the ionic conductivity and elasticity of the SEI film are improved, the contact between a negative electrode and an electrolyte in a battery is effectively avoided, the occurrence of side reactions is reduced, the consumption and the deterioration of the electrolyte in the using process are reduced, and the performance of the battery is improved; the SEI film formed by VC contains a polyalkyl lithium carbonate compound, the toughness of the SEI film can be further enhanced by the macromolecular alkyl chain of the polymer, and the additive comprises a sultone compound with a structure shown in formula I and VC in a compounding manner, so that the cycling stability of the battery is improved.
Preferably, the organic solvent is selected from any one of or a combination of at least two of Ethylene Carbonate (EC), propylene Carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl Methyl Carbonate (EMC), propylene Sulfite (PS), ethyl Acetate (EA), ethyl Propionate (EP), diethyl sulfite (DES), or 1, 3-propane sultone (1, 3-PS); more preferably a combination of at least two of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, or ethyl methyl carbonate; still more preferred is a combination of ethylene carbonate, propylene carbonate, diethyl carbonate and ethyl methyl carbonate.
Preferably, the electrolyte contains 15 to 25% by weight of ethylene carbonate, for example, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23% or 24%, and the specific values therebetween are not exhaustive for the invention, and for brevity and conciseness.
Preferably, the electrolyte contains 0.001 to 5% by mass of propylene carbonate, for example, 0.002%, 0.005%, 0.008%, 0.01%, 0.03%, 0.05%, 0.08%, 0.1%, 0.3%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, or 4.5%, and specific values therebetween are not intended to be exhaustive, and for the sake of brevity and conciseness, and the invention does not include the range of specific values.
Preferably, the electrolyte solution contains 15 to 20% by mass of diethyl carbonate, for example, 15.5%, 16%, 16.5%, 17%, 17.5%, 18%, 18.5%, 19% or 19.5%, and specific values therebetween, which are not exhaustive, for reasons of brevity and conciseness.
Preferably, the percentage by mass of the ethyl methyl carbonate in the electrolyte is 40 to 45%, for example, 40.5%, 41%, 41.5%, 42%, 42.5%, 43%, 43.5%, 44% or 44.5%, and specific values therebetween, which are limited by space and for brevity, are not exhaustive, and the specific values included in the range are not included.
In a second aspect, the present invention provides a method for preparing the electrolyte according to the first aspect, the method comprising: and mixing lithium salt, an additive and an organic solvent to obtain the electrolyte.
In a third aspect, the present invention provides a lithium ion battery, which includes a positive electrode plate, a negative electrode plate, an electrolyte, and a diaphragm disposed between the positive electrode plate and the negative electrode plate; the electrolyte is the electrolyte according to the first aspect.
Preferably, the lithium ion battery further comprises a casing, and the positive pole piece, the negative pole piece, the electrolyte and the diaphragm are accommodated in the casing.
Preferably, the positive pole piece comprises a positive pole current collector and a positive pole material.
Preferably, the positive electrode material includes a combination of a positive electrode active material, a positive electrode binder, and optionally a conductive agent.
Preferably, the negative electrode sheet includes a negative electrode current collector and a negative electrode material.
Preferably, the negative electrode material includes a combination of a negative electrode active material, a negative electrode binder, and a conductive agent.
In the present invention, the positive electrode material (positive electrode active material, positive electrode binder, and conductive agent) and the negative electrode material (negative electrode active material, negative electrode binder, and conductive agent) are conventional materials in the art, and are not described in detail for brevity.
Compared with the prior art, the invention has the following beneficial effects:
according to the electrolyte provided by the invention, through the design of components, particularly, a sultone compound with a specific structure is used as an additive, a compact, stable and elastic SEI film is formed in the charging and discharging processes of a battery, the lithium ion conductivity of the SEI film is improved, the impedance can be effectively reduced, the occurrence of side reactions is reduced, the consumption and the deterioration of the electrolyte in the using process are reduced, the normal-temperature and high-temperature cycle performance of the battery is improved, the internal resistance of the battery is reduced to 0.85-0.88 m omega, the capacity retention rate is improved, the capacity retention rate of the lithium ion battery is reduced to 94.7-95.3% after being cycled for 1000 cycles at 25 ℃, the expansion rate is less than 0.04%, the capacity retention rate of the lithium ion battery after being cycled for 1000 cycles at 45 ℃ is greater than 91%, 91.4-93.3%, the expansion rate is less than or equal to 0.24%, and the service life of the battery is prolonged.
Detailed Description
The technical solution of the present invention is further explained by the following embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.
Example 1
The embodiment provides an electrolyte and a preparation method thereof, wherein the electrolyte comprises the following components in percentage by mass: 12.5% of lithium hexafluorophosphate, 0.5% of lithium difluorophosphate, a sultone compound (a structure shown in formula II,
) 0.5 percent of vinylene carbonate, and the balance of organic solvent; the organic solvent is a mixed solvent of ethylene carbonate, propylene carbonate, ethyl methyl carbonate and diethyl carbonate in a mass ratio of (5).
The preparation method of the electrolyte comprises the following steps: and uniformly mixing lithium hexafluorophosphate, lithium difluorophosphate, a sultone compound, vinylene carbonate and an organic solvent according to the formula amount to obtain the electrolyte.
Example 2
This example provides an electrolyte and a method for preparing the same, which are different from example 1 only in that the sultone compound has a structure represented by formula III
Example 3
This example provides an electrolyte and a method for preparing the same, which are different from example 1 only in that the sultone compound has a structure represented by formula IV
Other components, ratios and preparation methods are the same as those of example 1.
Example 4
This example provides an electrolyte and a method for preparing the same, which are different from example 1 only in that the sultone compound has a structure represented by formula V
Other components, ratios and preparation methods are the same as those of example 1.
Example 5
This example provides an electrolyte and a method for preparing the same, which are different from example 1 only in that the sultone compound has a structure represented by formula VI
Other components, proportions and preparation methods are the same as those in example 1。
Example 6
The embodiment provides an electrolyte and a preparation method thereof, wherein the electrolyte comprises the following components in percentage by mass: 12.5% of lithium hexafluorophosphate, 0.5% of a sultone compound (a structure shown in a formula II), 3% of vinylene carbonate and the balance of an organic solvent; the organic solvent is a mixed solvent of ethylene carbonate, propylene carbonate, ethyl methyl carbonate and diethyl carbonate in a mass ratio of (5).
The preparation method of the electrolyte comprises the following steps: and uniformly mixing lithium hexafluorophosphate, a sultone compound, vinylene carbonate and an organic solvent according to the formula amount to obtain the electrolyte.
Example 7
The embodiment provides an electrolyte and a preparation method thereof, wherein the electrolyte comprises the following components in percentage by mass: 12.5% of lithium hexafluorophosphate, 0.5% of lithium difluorophosphate, 3.5% of a sultone compound (a structure shown in a formula II) and the balance of an organic solvent; the organic solvent is a mixed solvent of ethylene carbonate, propylene carbonate, ethyl methyl carbonate and diethyl carbonate in a mass ratio of 5.
The preparation method of the electrolyte comprises the following steps: and uniformly mixing lithium hexafluorophosphate, lithium difluorophosphate, a sultone compound and an organic solvent according to the formula amount to obtain the electrolyte.
Example 8
The embodiment provides an electrolyte and a preparation method thereof, wherein the electrolyte comprises the following components in percentage by mass: 12.5% of lithium hexafluorophosphate, 0.5% of lithium difluorophosphate, 0.3% of a sultone compound (a structure shown in a formula II), 3.2% of vinylene carbonate and the balance of an organic solvent; the organic solvent is a mixed solvent of ethylene carbonate, propylene carbonate, ethyl methyl carbonate and diethyl carbonate in a mass ratio of 5; the preparation method is the same as that of example 1.
Example 9
The embodiment provides an electrolyte and a preparation method thereof, wherein the electrolyte comprises the following components in percentage by mass: 12.5% of lithium hexafluorophosphate, 0.5% of lithium difluorophosphate, 1% of a sultone compound (a structure shown in a formula II), 2.5% of vinylene carbonate and the balance of an organic solvent; the organic solvent is a mixed solvent of ethylene carbonate, propylene carbonate, ethyl methyl carbonate and diethyl carbonate in a mass ratio of 5; the preparation method is the same as that of example 1.
Comparative example 1
The comparative example provides an electrolyte and a preparation method thereof, wherein the electrolyte comprises the following components in percentage by mass: 12.5% of lithium hexafluorophosphate, 0.5% of lithium difluorophosphate, 3% of vinylene carbonate and the balance of organic solvent; the organic solvent is a mixed solvent of ethylene carbonate, propylene carbonate, ethyl methyl carbonate and diethyl carbonate in a mass ratio of 5; the preparation method is the same as that of example 1.
Comparative example 2
The comparative example provides an electrolyte and a preparation method thereof, wherein the electrolyte comprises the following components in percentage by mass: 12.5% of lithium hexafluorophosphate, 0.5% of lithium difluorophosphate, 3.5% of vinylene carbonate and the balance of an organic solvent; the organic solvent is a mixed solvent of ethylene carbonate, propylene carbonate, ethyl methyl carbonate and diethyl carbonate in a mass ratio of 5; the preparation method is the same as that of example 1.
Comparative example 3
The comparative example provides an electrolyte and a preparation method thereof, and the electrolyte comprises the following components in percentage by mass: 12.5% of lithium hexafluorophosphate, 3% of vinylene carbonate and the balance of an organic solvent; the organic solvent is a mixed solvent of ethylene carbonate, propylene carbonate, ethyl methyl carbonate and diethyl carbonate in a mass ratio of (5); the preparation method is the same as that of example 1.
Comparative example 4
The embodiment provides an electrolyte and a preparation method thereof, wherein the electrolyte comprises the following components in percentage by mass: 12.5% of lithium hexafluorophosphate, 0.5% of lithium difluorophosphate, 0.5% of 1, 4-butanesultone, 3% of vinylene carbonate and the balance of organic solvent; the organic solvent is a mixed solvent of ethylene carbonate, propylene carbonate, ethyl methyl carbonate and diethyl carbonate in a mass ratio of (5); the preparation method is the same as that of example 1.
Comparative example 5
The embodiment provides an electrolyte and a preparation method thereof, wherein the electrolyte comprises the following components in percentage by mass: 12.5% of lithium hexafluorophosphate, 0.5% of lithium difluorophosphate, 0.5% of methylene methanedisulfonate, 3% of vinylene carbonate and the balance of an organic solvent; the organic solvent is a mixed solvent of ethylene carbonate, propylene carbonate, ethyl methyl carbonate and diethyl carbonate in a mass ratio of 5; the preparation method is the same as in example 1.
Application example
A lithium ion battery, the lithium iron phosphate battery model is square aluminum shell-105 Ah, the normal temperature capacity distribution is 107-110 Ah, the charging and discharging voltage range is 2.5-3.2V, and the normal temperature 1C multiplying power is circulated continuously; the electrolyte comprises a positive pole piece, a negative pole piece, electrolyte and a diaphragm, wherein the electrolyte is respectively provided by embodiments 1-8 and comparative examples 1-4; the preparation method comprises the following steps:
(1) Preparing a positive pole piece: liFePO 4 : SP (conductive carbon black): CNT (carbon nanotube): PVDF (polytetrafluoroethylene) =95.0:2.0:0.5:2.5; preparing glue by using the anode, wherein the solid content of the glue solution is 1.327 percent; the first step of adding LiFePO 4 The SP and the NMP revolve at 25r/min, disperse at 500r/min, stir for 10min, then revolve at 25r/min, disperse at 1000 +/-50 r/min, stir for 90min at 45 ℃; secondly, adding conductive agent CNT slurry, revolving for 25r/min, dispersing for 1000r/min, keeping the vacuum degree at 0.080kPa, and stirring for 60min at 45 ℃; thirdly, adding the positive glue solution, revolving for 25r/min, dispersing for 2500r/min, keeping the vacuum degree at 0.080kPa, and stirring for 90min at 45 ℃; the fourth step is a viscosity adjusting step, NMP (N-methyl pyrrolidone) is added to adjust the viscosity of the slurry; fifthly, slowly stirring and revolving for 15r/min, dispersing for 500r/min, stirring for 0.5h under the vacuum degree of 0.080kPa, cooling, ensuring the discharging viscosity of the anode to be 20000mPa & s and the fineness to be less than or equal to 15 mu m, and scraping the deposited materials on the stirring cylinder wall and the stirring rod in time in each step. Sieving, coating, cold pressing and cutting to obtain a positive pole piece;
(2) Preparing a negative pole piece: graphite: SP: CMC (sodium carboxymethylcellulose): SBR (styrene butadiene rubber) =95.5:1.5:1.2:1.8; preparing glue at the negative electrode, wherein the solid content of the glue solution is 8%, adding graphite and SP in the first step, performing dry mixing and revolution for 20r/min, dispersing for 1000r/min, and stirring for 1h; secondly, adding 50 percent of negative pole slurry, revolving for 20r/min, dispersing for 1000r/min, and stirring for 1.5h; thirdly, adding the other 50 percent of negative pole glue solution, revolving for 25r/min, dispersing for 2000r/min, keeping the vacuum degree at 0.085kPa, and stirring for 1h; the fourth step is a viscosity adjusting step, deionized water is added to adjust the viscosity of the slurry; and fifthly, adding a water system dispersant SBR, revolving for 25r/min, dispersing for 800r/min, keeping the vacuum degree at 0.085kPa, and stirring for 1 h. The discharging viscosity of the negative electrode is guaranteed to be 4000 mPas, the fineness is less than or equal to 20 mu m, and the deposited materials on the wall of the stirring cylinder and the stirring rod are scraped in time in each step. And sieving, coating, cold pressing and cutting to obtain the negative pole piece.
(3) And assembling the positive pole piece, the negative pole piece and the diaphragm, and then injecting electrolyte to prepare the lithium ion battery.
The performance test of the lithium ion battery is carried out by the following method:
(1) Internal resistance: taking 3 lithium ion batteries to be tested respectively, and carrying out charge-discharge cycle test on the lithium ion batteries by 0.5C (55A) current for 13 circles on a macro battery test cabinet in a constant temperature box at 25 ℃, wherein the charge-discharge voltage interval is 2.5-3.65V; then discharging to 50% of the total capacity, discharging for 10s with 1C (110A) current, and recording the voltage change before and after discharging; internal resistance = voltage difference before and after discharge/discharge current.
(2) Capacity retention ratio: taking 3 lithium ion batteries to be tested respectively, and carrying out charge-discharge cycle test on the lithium ion batteries by using 1C (110A) current for 1000 circles on a macro battery test cabinet in a constant temperature box at the temperature of 25 ℃/45 ℃, wherein the charge-discharge voltage interval is 2.5-3.65V; capacity retention was calculated for 1000 cycles at 25 ℃ and 45 ℃ respectively: capacity retention = discharge capacity at 1000 cycles/first discharge capacity × 100%.
(3) Expansion ratio: the thickness of the battery before the cycle and the thickness of the battery after 1000 cycles were measured, respectively, and the expansion rate = (the thickness of the battery after 1000 cycles-the thickness of the battery before the cycle test)/the thickness of the battery before the cycle test × 100%.
The test results are shown in table 1:
TABLE 1
According to the performance test data in the table 1, the sultone compound with a specific structure is adopted as the additive in the electrolyte provided by the invention, so that the impedance can be effectively reduced, the internal resistance is reduced to 0.85-0.88 m omega, the capacity retention rate is high, the capacity retention rate is 94.7-95.3% after 1000 cycles of 25 ℃, the expansion rate is less than 0.04%, and the expansion rate is 0.02-0.03%; the capacity retention rate of 1000 cycles at 45 ℃ is 91.4-93.3%, the expansion rate is 0.15-0.24%, the normal temperature and high temperature cycle performance of the lithium ion battery is effectively improved, and the service life of the battery is prolonged. Meanwhile, compared with an electrolyte (example 7) in which a single-component sultone compound is used as an additive, the electrolyte (for example, examples 1 to 5) containing a combination of a sultone compound having a specific structure and vinylene carbonate is more favorable for improving the capacity retention rate and the cycle performance of a battery, and has better normal-temperature and high-temperature cyclicity.
Compared with example 1, if the electrolyte does not contain the sultone compound additive with the structure shown in formula I (comparative examples 1 and 3) in the invention, even if the amount of vinylene carbonate (comparative example 2) is increased, the impedance cannot be effectively reduced, so that the capacity retention rate of the battery after multiple cycles is low, and the cycle performance is deteriorated.
Compared to example 1, if the sultone compound additive having the structure shown in I of the present invention is replaced with other sultone compounds (comparative examples 4 and 5), trace amount of water during the cycle cannot be effectively captured, the SEI film structure is gradually broken down, thereby deteriorating the cycle performance and generating much gas.
The applicant states that the present invention is illustrated by the above examples to describe an electrolyte and a preparation method and application thereof, but the present invention is not limited to the above examples, i.e. it is not meant that the present invention must be implemented by the above examples. It should be understood by those skilled in the art that any modification of the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.
Claims (28)
1. An electrolyte, characterized in that the electrolyte comprises a lithium salt, an additive and an organic solvent; the additive comprises a sultone compound with a structure shown in a formula I:
wherein R is 1 、R 2 Each independently selected from any one of C1-C10 straight chain or branched chain alkyl, C2-C10 alkenyl, C2-C10 alkynyl or phenyl;
a is CH or N;
R 3 selected from hydrogen, C1-C10 straight chain or branched chain alkyl, C2-C10 alkenyl, C2-C10 alkynyl or
Any one of the above;
* Represents the linking site of the group, and m is an integer of 0 to 3;
R 4 is selected from any one of hydrogen, halogen and C1-C10 straight chain or branched chain alkyl.
2. The electrolyte of claim 1, wherein R is 1 、R 2 Each independently is methyl, ethyl or phenyl; the R is 1 And R 2 Is not connected or connected by chemical bonds to form C4-C5 saturated nitrogen heterocycles.
3. The electrolyte of claim 1, wherein R is 3 Selected from hydrogen, methyl or benzyl.
4. The electrolyte of claim 1, wherein R is 4 Selected from hydrogen, halogen or methyl.
5. The electrolyte of claim 1, wherein the sultone compound has a structure according to any one of formula II, formula III, formula IV, formula V, or formula VI:
6. the electrolyte according to claim 1, wherein the sultone compound is contained in the electrolyte in an amount of 0.1 to 1.0% by mass.
7. The electrolyte according to claim 6, wherein the mass percentage of the sultone compound in the electrolyte is 0.3-0.8%.
8. The electrolyte according to claim 1, wherein the lithium salt is present in the electrolyte in an amount of 10 to 20% by mass.
9. The electrolyte of claim 8, wherein the lithium salt is present in the electrolyte in an amount of 12 to 16% by weight.
10. The electrolyte of claim 1, wherein the lithium salt is selected from any one of or a combination of at least two of lithium hexafluorophosphate, lithium perchlorate, lithium tetrafluoroborate, lithium difluorophosphate, lithium dioxalate borate, lithium difluorooxalate borate, or lithium bis (fluorosulfonyl) imide.
11. The electrolyte of claim 10, wherein the lithium salt comprises lithium hexafluorophosphate and optionally lithium difluorophosphate.
12. The electrolyte according to claim 10, wherein the lithium hexafluorophosphate is present in an amount of 12 to 14% by mass.
13. The electrolyte of claim 10, wherein the lithium difluorophosphate is present in the electrolyte in an amount of 0.5 to 2% by weight.
14. The electrolyte of claim 1, wherein the additive further comprises vinylene sulfate and/or vinylene carbonate.
15. The electrolyte of claim 14, wherein the electrolyte contains 0.5 to 4% by mass of vinylene sulfate.
16. The electrolyte according to claim 14, wherein the vinylene carbonate is present in the electrolyte in an amount of 0.5-4% by mass.
17. The electrolyte of claim 1, wherein the organic solvent is selected from any one of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, propylene sulfite, ethyl acetate, ethyl propionate, diethyl sulfite, or 1, 3-propane sultone, or a combination of at least two thereof.
18. The electrolyte of claim 17, wherein the organic solvent is a combination of at least two of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, or ethyl methyl carbonate.
19. The electrolyte of claim 18, wherein the electrolyte contains 15-25% by weight of ethylene carbonate.
20. The electrolyte of claim 18, wherein the propylene carbonate is present in the electrolyte in an amount of 0.001 to 5% by weight.
21. The electrolyte according to claim 18, wherein the electrolyte comprises 15-20% by weight of diethyl carbonate.
22. The electrolyte of claim 18, wherein the mass percentage of ethyl methyl carbonate in the electrolyte is 40-45%.
23. A method of preparing the electrolyte of any of claims 1-22, comprising: and mixing lithium salt, an additive and an organic solvent to obtain the electrolyte.
24. A lithium ion battery is characterized by comprising a positive pole piece, a negative pole piece, electrolyte and a diaphragm arranged between the positive pole piece and the negative pole piece; the electrolyte solution according to any one of claims 1 to 22.
25. The lithium ion battery of claim 24, wherein the positive pole piece comprises a positive current collector and a positive material.
26. The lithium ion battery of claim 25, wherein the positive electrode material comprises a combination of a positive electrode active material, a positive electrode binder, and optionally a conductive agent.
27. The lithium ion battery of claim 24, wherein the negative electrode tab comprises a negative electrode current collector and a negative electrode material.
28. The lithium ion battery of claim 27, wherein the negative electrode material comprises a combination of a negative electrode active material, a negative electrode binder, and a conductive agent.
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| JP2009245829A (en) * | 2008-03-31 | 2009-10-22 | Sanyo Electric Co Ltd | Nonaqueous electrolyte and nonaqueous electrolyte secondary battery containing nonaqueous electrolyte |
| CN102914929A (en) * | 2011-08-05 | 2013-02-06 | 三星电子株式会社 | Electrochromic device |
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| Synthesis of N,N -disubstituted cis and trans 4-amino-3-chloro-3,4,5,6,7,8-hexahydro-1,2-benzoxathiin 2,2-dioxides, and 4-amino-5,6,7,8-tetrahydro-1,2-benzoxathiin 2,2-dioxides;Alberto Bargagna et al.;《Journal of heterocyclic chemistry》;19831231;第20卷;全文 * |
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