CN118507827A - Electrolyte, lithium ion battery and electric equipment - Google Patents
Electrolyte, lithium ion battery and electric equipment Download PDFInfo
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- CN118507827A CN118507827A CN202410125059.7A CN202410125059A CN118507827A CN 118507827 A CN118507827 A CN 118507827A CN 202410125059 A CN202410125059 A CN 202410125059A CN 118507827 A CN118507827 A CN 118507827A
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- electrolyte
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- additive
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- 239000003792 electrolyte Substances 0.000 title claims abstract description 106
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims abstract description 27
- 229910001416 lithium ion Inorganic materials 0.000 title claims abstract description 27
- 239000000654 additive Substances 0.000 claims abstract description 91
- 230000000996 additive effect Effects 0.000 claims abstract description 79
- 125000003118 aryl group Chemical group 0.000 claims abstract description 25
- 229910003002 lithium salt Inorganic materials 0.000 claims abstract description 12
- 159000000002 lithium salts Chemical class 0.000 claims abstract description 12
- 239000003960 organic solvent Substances 0.000 claims abstract description 9
- -1 benzopyrrolyl group Chemical group 0.000 claims description 21
- SBLRHMKNNHXPHG-UHFFFAOYSA-N 4-fluoro-1,3-dioxolan-2-one Chemical compound FC1COC(=O)O1 SBLRHMKNNHXPHG-UHFFFAOYSA-N 0.000 claims description 20
- 125000003545 alkoxy group Chemical group 0.000 claims description 10
- 229910052744 lithium Inorganic materials 0.000 claims description 10
- 125000004093 cyano group Chemical group *C#N 0.000 claims description 9
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 claims description 8
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 8
- 125000003342 alkenyl group Chemical group 0.000 claims description 8
- 125000000304 alkynyl group Chemical group 0.000 claims description 8
- 150000005676 cyclic carbonates Chemical class 0.000 claims description 8
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 claims description 7
- 125000000753 cycloalkyl group Chemical group 0.000 claims description 7
- 125000001424 substituent group Chemical group 0.000 claims description 7
- 125000005843 halogen group Chemical group 0.000 claims description 6
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 claims description 6
- 125000003107 substituted aryl group Chemical group 0.000 claims description 4
- 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 claims description 3
- VMZOBROUFBEGAR-UHFFFAOYSA-N tris(trimethylsilyl) phosphite Chemical compound C[Si](C)(C)OP(O[Si](C)(C)C)O[Si](C)(C)C VMZOBROUFBEGAR-UHFFFAOYSA-N 0.000 claims description 3
- BAASCWKOCWNWKR-UHFFFAOYSA-N 1,3,2-dioxathiole 2-oxide Chemical compound O=S1OC=CO1 BAASCWKOCWNWKR-UHFFFAOYSA-N 0.000 claims description 2
- SJHAYVFVKRXMKG-UHFFFAOYSA-N 4-methyl-1,3,2-dioxathiolane 2-oxide Chemical compound CC1COS(=O)O1 SJHAYVFVKRXMKG-UHFFFAOYSA-N 0.000 claims description 2
- 229910019142 PO4 Inorganic materials 0.000 claims description 2
- 125000005428 anthryl group Chemical group [H]C1=C([H])C([H])=C2C([H])=C3C(*)=C([H])C([H])=C([H])C3=C([H])C2=C1[H] 0.000 claims description 2
- 125000000499 benzofuranyl group Chemical group O1C(=CC2=C1C=CC=C2)* 0.000 claims description 2
- 125000004196 benzothienyl group Chemical group S1C(=CC2=C1C=CC=C2)* 0.000 claims description 2
- 150000001875 compounds Chemical class 0.000 claims description 2
- 125000002704 decyl 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])C([H])([H])C([H])([H])C([H])([H])* 0.000 claims description 2
- 125000004988 dibenzothienyl group Chemical group C1(=CC=CC=2SC3=C(C21)C=CC=C3)* 0.000 claims description 2
- VEWLDLAARDMXSB-UHFFFAOYSA-N ethenyl sulfate;hydron Chemical compound OS(=O)(=O)OC=C VEWLDLAARDMXSB-UHFFFAOYSA-N 0.000 claims description 2
- 125000003983 fluorenyl group Chemical group C1(=CC=CC=2C3=CC=CC=C3CC12)* 0.000 claims description 2
- 125000001261 isocyanato group Chemical group *N=C=O 0.000 claims description 2
- 125000001624 naphthyl group Chemical group 0.000 claims description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims description 2
- 239000010452 phosphate Substances 0.000 claims description 2
- 239000007784 solid electrolyte Substances 0.000 abstract description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 35
- 229910052759 nickel Inorganic materials 0.000 description 17
- 239000002904 solvent Substances 0.000 description 15
- 239000000463 material Substances 0.000 description 12
- 238000003860 storage Methods 0.000 description 11
- 230000000052 comparative effect Effects 0.000 description 10
- 239000007774 positive electrode material Substances 0.000 description 9
- 238000012360 testing method Methods 0.000 description 8
- 230000000694 effects Effects 0.000 description 7
- 238000000034 method Methods 0.000 description 7
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 6
- 229910013870 LiPF 6 Inorganic materials 0.000 description 6
- 125000000217 alkyl group Chemical group 0.000 description 6
- 125000001297 nitrogen containing inorganic group Chemical group 0.000 description 6
- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 description 5
- 210000004027 cell Anatomy 0.000 description 5
- 239000007789 gas Substances 0.000 description 5
- 125000005842 heteroatom Chemical group 0.000 description 5
- 239000011572 manganese Substances 0.000 description 5
- 230000003647 oxidation Effects 0.000 description 5
- 238000007254 oxidation reaction Methods 0.000 description 5
- 239000011230 binding agent Substances 0.000 description 4
- 239000006258 conductive agent Substances 0.000 description 4
- 238000000354 decomposition reaction Methods 0.000 description 4
- 230000014759 maintenance of location Effects 0.000 description 4
- 239000007773 negative electrode material Substances 0.000 description 4
- 238000007086 side reaction Methods 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- KFDQGLPGKXUTMZ-UHFFFAOYSA-N [Mn].[Co].[Ni] Chemical compound [Mn].[Co].[Ni] KFDQGLPGKXUTMZ-UHFFFAOYSA-N 0.000 description 3
- 150000001408 amides Chemical class 0.000 description 3
- 150000008430 aromatic amides Chemical class 0.000 description 3
- 238000007599 discharging Methods 0.000 description 3
- 230000002349 favourable effect Effects 0.000 description 3
- 238000004770 highest occupied molecular orbital Methods 0.000 description 3
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- IQPQWNKOIGAROB-UHFFFAOYSA-N isocyanate group Chemical group [N-]=C=O IQPQWNKOIGAROB-UHFFFAOYSA-N 0.000 description 3
- 238000002386 leaching Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- BQCIDUSAKPWEOX-UHFFFAOYSA-N 1,1-Difluoroethene Chemical compound FC(F)=C BQCIDUSAKPWEOX-UHFFFAOYSA-N 0.000 description 2
- VAYTZRYEBVHVLE-UHFFFAOYSA-N 1,3-dioxol-2-one Chemical compound O=C1OC=CO1 VAYTZRYEBVHVLE-UHFFFAOYSA-N 0.000 description 2
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 102100028667 C-type lectin domain family 4 member A Human genes 0.000 description 2
- 101000766908 Homo sapiens C-type lectin domain family 4 member A Proteins 0.000 description 2
- 229910002991 LiNi0.5Co0.2Mn0.3O2 Inorganic materials 0.000 description 2
- 230000006978 adaptation Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000001768 carboxy methyl cellulose Substances 0.000 description 2
- 230000021615 conjugation Effects 0.000 description 2
- 210000001787 dendrite Anatomy 0.000 description 2
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 238000003487 electrochemical reaction Methods 0.000 description 2
- 125000004185 ester group Chemical group 0.000 description 2
- 229910052731 fluorine Inorganic materials 0.000 description 2
- 238000009616 inductively coupled plasma Methods 0.000 description 2
- 238000004768 lowest unoccupied molecular orbital Methods 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 229910021645 metal ion Inorganic materials 0.000 description 2
- DVSDBMFJEQPWNO-UHFFFAOYSA-N methyllithium Chemical compound C[Li] DVSDBMFJEQPWNO-UHFFFAOYSA-N 0.000 description 2
- 239000012046 mixed solvent Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000006864 oxidative decomposition reaction Methods 0.000 description 2
- 238000011056 performance test Methods 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 description 2
- 230000002195 synergetic effect Effects 0.000 description 2
- BHZCMUVGYXEBMY-UHFFFAOYSA-N trilithium;azanide Chemical compound [Li+].[Li+].[Li+].[NH2-] BHZCMUVGYXEBMY-UHFFFAOYSA-N 0.000 description 2
- 238000001291 vacuum drying Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- ZZXUZKXVROWEIF-UHFFFAOYSA-N 1,2-butylene carbonate Chemical compound CCC1COC(=O)O1 ZZXUZKXVROWEIF-UHFFFAOYSA-N 0.000 description 1
- LOURZMYQPMDBSR-UHFFFAOYSA-N 1,3,2-dioxathiane 2-oxide Chemical compound O=S1OCCCO1 LOURZMYQPMDBSR-UHFFFAOYSA-N 0.000 description 1
- ZCYVEMRRCGMTRW-UHFFFAOYSA-N 7553-56-2 Chemical group [I] ZCYVEMRRCGMTRW-UHFFFAOYSA-N 0.000 description 1
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical group [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- WKBOTKDWSSQWDR-UHFFFAOYSA-N Bromine atom Chemical group [Br] WKBOTKDWSSQWDR-UHFFFAOYSA-N 0.000 description 1
- 101150085274 CLEC4A gene Proteins 0.000 description 1
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229910019549 CoyMzO2 Inorganic materials 0.000 description 1
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 1
- 229910018068 Li 2 O Inorganic materials 0.000 description 1
- 229910012851 LiCoO 2 Inorganic materials 0.000 description 1
- 229910013716 LiNi Inorganic materials 0.000 description 1
- 229910013825 LiNi0.33Co0.33Mn0.33O2 Inorganic materials 0.000 description 1
- 229910011328 LiNi0.6Co0.2Mn0.2O2 Inorganic materials 0.000 description 1
- 229910015872 LiNi0.8Co0.1Mn0.1O2 Inorganic materials 0.000 description 1
- 229910001228 Li[Ni1/3Co1/3Mn1/3]O2 (NCM 111) Inorganic materials 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- BUGBHKTXTAQXES-UHFFFAOYSA-N Selenium Chemical group [Se] BUGBHKTXTAQXES-UHFFFAOYSA-N 0.000 description 1
- HMDDXIMCDZRSNE-UHFFFAOYSA-N [C].[Si] Chemical compound [C].[Si] HMDDXIMCDZRSNE-UHFFFAOYSA-N 0.000 description 1
- CVTZKFWZDBJAHE-UHFFFAOYSA-N [N].N Chemical group [N].N CVTZKFWZDBJAHE-UHFFFAOYSA-N 0.000 description 1
- 229960001413 acetanilide Drugs 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
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 239000010405 anode material Substances 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 229910021383 artificial graphite Inorganic materials 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 235000010290 biphenyl Nutrition 0.000 description 1
- 150000004074 biphenyls Chemical class 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 239000002041 carbon nanotube Substances 0.000 description 1
- 229910021393 carbon nanotube Inorganic materials 0.000 description 1
- 239000003575 carbonaceous material Substances 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 1
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 125000001309 chloro group Chemical group Cl* 0.000 description 1
- 239000011889 copper foil Substances 0.000 description 1
- 125000000113 cyclohexyl group Chemical group [H]C1([H])C([H])([H])C([H])([H])C([H])(*)C([H])([H])C1([H])[H] 0.000 description 1
- 125000001511 cyclopentyl group Chemical group [H]C1([H])C([H])([H])C([H])([H])C([H])(*)C1([H])[H] 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 230000000593 degrading effect Effects 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000005868 electrolysis reaction Methods 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 125000001153 fluoro group Chemical group F* 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 239000007770 graphite material Substances 0.000 description 1
- 125000001072 heteroaryl group Chemical group 0.000 description 1
- 125000004051 hexyl group Chemical group [H]C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])* 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 229910052740 iodine Inorganic materials 0.000 description 1
- 230000002427 irreversible effect Effects 0.000 description 1
- 229910000625 lithium cobalt oxide 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
- FRMOHNDAXZZWQI-UHFFFAOYSA-N lithium manganese(2+) nickel(2+) oxygen(2-) Chemical compound [O-2].[Mn+2].[Ni+2].[Li+] FRMOHNDAXZZWQI-UHFFFAOYSA-N 0.000 description 1
- 229910001386 lithium phosphate Inorganic materials 0.000 description 1
- DVATZODUVBMYHN-UHFFFAOYSA-K lithium;iron(2+);manganese(2+);phosphate Chemical compound [Li+].[Mn+2].[Fe+2].[O-]P([O-])([O-])=O DVATZODUVBMYHN-UHFFFAOYSA-K 0.000 description 1
- BFZPBUKRYWOWDV-UHFFFAOYSA-N lithium;oxido(oxo)cobalt Chemical compound [Li+].[O-][Co]=O BFZPBUKRYWOWDV-UHFFFAOYSA-N 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000011325 microbead Substances 0.000 description 1
- 229910021382 natural graphite Inorganic materials 0.000 description 1
- 150000002825 nitriles Chemical class 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 125000004433 nitrogen atom Chemical group N* 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 125000004430 oxygen atom Chemical group O* 0.000 description 1
- 125000004437 phosphorous atom Chemical group 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 125000003367 polycyclic group Chemical group 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000007790 scraping Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 229910052711 selenium Inorganic materials 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 235000019812 sodium carboxymethyl cellulose Nutrition 0.000 description 1
- 229920001027 sodium carboxymethylcellulose Polymers 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 125000005017 substituted alkenyl group Chemical group 0.000 description 1
- 125000005415 substituted alkoxy group Chemical group 0.000 description 1
- 125000000547 substituted alkyl group Chemical group 0.000 description 1
- 125000004426 substituted alkynyl group Chemical group 0.000 description 1
- 125000005346 substituted cycloalkyl group Chemical group 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 125000004434 sulfur atom Chemical group 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
- 239000002562 thickening agent Substances 0.000 description 1
- TWQULNDIKKJZPH-UHFFFAOYSA-K trilithium;phosphate Chemical compound [Li+].[Li+].[Li+].[O-]P([O-])([O-])=O TWQULNDIKKJZPH-UHFFFAOYSA-K 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
- 238000009736 wetting Methods 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
- 229910052727 yttrium 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
-
- 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 application provides an electrolyte, a lithium ion battery and electric equipment, wherein the electrolyte comprises lithium salt, an organic solvent and an additive shown as a formula (I):
Description
Technical Field
The application relates to the technical field of lithium ion batteries, in particular to electrolyte, a lithium ion battery and electric equipment.
Background
The traditional commercial lithium battery electrolyte is easy to be subjected to oxidative decomposition in a high-voltage environment, so that the electrolyte is consumed rapidly, the metal ions of the anode material are dissolved out rapidly, the surface impedance of the anode is increased, and the cycle performance and the safety performance of the battery are seriously reduced. Therefore, there is a need to develop lithium ion battery electrolytes that can withstand high voltages without degrading battery performance.
Disclosure of Invention
In view of the above, the application provides an electrolyte, a lithium ion battery and electric equipment, wherein the fluorinated aromatic amide additive contained in the electrolyte can respectively generate a stable anode electrolyte interface (CEI) film and a solid electrolyte interface (solid electrolyte interface, SEI) film on the surfaces of the anode and the cathode of the battery, and the battery adopting the electrolyte has better high-voltage stability and high-voltage cycle performance.
Specifically, the first aspect of the application provides an electrolyte comprising a lithium salt, an organic solvent, and an additive as shown in formula (I):
in formula (I), ar is selected from substituted or unsubstituted aryl.
The electrolyte is introduced with the fluoro aromatic amide additive shown in the formula (I), the additive can be reduced on the surface of a negative electrode in preference to a solvent to form a compact and stable SEI film, the stable CEI film is formed on the surface of a positive electrode in preference to the oxidation of the solvent, the consumption of the solvent can be reduced, the high-pressure resistance of the electrolyte is improved, and the SEI film and the CEI film also contain nitrogen-containing inorganic components with high ionic conductivity generated by the decomposition of the additive, so that the interface condition of the positive electrode/negative electrode and the electrolyte can be effectively improved by the CEI film and the SEI film, the interface impedance is reduced, the high-voltage stability, the high-voltage cycle performance and the coulombic efficiency of a battery are effectively improved, the gas expansion of the battery is reduced, and the like.
The second aspect of the application provides a lithium ion battery comprising the electrolyte provided in the first aspect of the application. Specifically, the battery comprises a battery shell, an electric core and electrolyte, wherein the electric core and the electrolyte are contained in the battery shell. The battery cell comprises a positive pole piece, a negative pole piece and a diaphragm positioned between the positive pole piece and the negative pole piece.
The battery has good high-voltage resistance, excellent high-temperature storage property and high-voltage cycle performance, and good high-temperature expansion property, so that the battery has high safety performance and long service life.
The third aspect of the application provides electric equipment, which comprises the lithium ion battery provided by the second aspect of the application. The lithium ion battery can supply power for the electric equipment.
Detailed Description
The high nickel ternary positive electrode material generally has a charge cutoff voltage of 4.5V (vs. Li/li+) or more, and when charged to 4.5V, it produces a large amount of strongly oxidizing Ni 4+. The traditional commercial lithium ion electrolyte mainly comprises a carbonate solvent and lithium salt (such as lithium hexafluorophosphate), when the voltage exceeds 4.5V, ni 4+ dissolved out from the positive electrode oxidizes the carbonate solvent, active lithium and the electrolyte are consumed, byproducts (such as water and other proton products) generated by rapid consumption of the electrolyte can accelerate the performance degradation of the electrolyte, the dissolution of metal ions in the high-nickel ternary positive electrode material is accelerated, the structural collapse of the positive electrode material is even caused, the interface film generated on the surfaces of the positive electrode and the negative electrode of the electrolyte is damaged, the impedance of the surface of the positive electrode is increased, and finally the gas expansion and the rapid capacity decay of the battery are caused. In addition, the high-nickel ternary positive electrode material is easy to generate oxygen evolution phenomenon under high potential, further accelerates the oxidative decomposition and gas generation of electrolyte, and finally leads to poor stability, increased impedance and reduced battery performance of the electrode interface film.
The replacement of the electrolyte solvent having a high oxidation resistance or the replacement of the lithium salt which generates less or no hydrofluoric acid can improve the high voltage resistance of the electrolyte, but the ionic conductivity of the electrolyte is lost or the viscosity of the electrolyte is excessively high, which affects the performance of the battery. The high voltage resistance of the electrolyte can be improved to a certain extent by introducing high voltage additives (such as nitriles, fluoroesters and the like) into the conventional electrolyte, but the electrolyte is difficult to generate a stable interface film on the surface of the positive electrode, and the cycle performance of the battery under a high voltage environment is limited to improve. In view of the above, the application provides an electrolyte with good high voltage resistance and without affecting the performance of a battery, and a lithium ion battery and electric equipment using the electrolyte.
The electrolyte provided by the embodiment of the application comprises the following components: lithium salt, organic solvent, and fluoroaromatic amide additive of formula (I):
in formula (I), ar is selected from substituted or unsubstituted aryl.
The fluorinated aromatic amide additive shown in the formula (I) is introduced into the electrolyte, and the conjugation effect formed between tertiary ammonia nitrogen atoms in the structure of the additive and aryl Ar and carbonyl-C (=O) -can reduce the Lowest Unoccupied Molecular Orbital (LUMO) energy of the additive, and according to the front line orbit theory, the reduction potential of the additive is higher, and the additive can be reduced on the surface of a negative electrode in preference to a solvent to form a compact and stable SEI film, so that the consumption of the solvent of the electrolyte is reduced, the interface condition of the negative electrode and the electrolyte (such as preventing the contact of the electrolyte and the negative electrode from generating side reaction) is improved, the high-temperature storage expansion rate and the gas yield of a battery are further reduced, and the high-voltage stability, the circulation performance and the safety performance of the battery are improved. Meanwhile, the conjugation effect can also improve the Highest Occupied Molecular Orbital (HOMO) energy of the additive, so that the additive can be oxidized on the surface of a positive electrode in preference to a solvent to form a stable CEI film, and the CEI film can prevent dissolution of nickel element in the nickel-containing ternary positive electrode material, prevent oxidation and decomposition of the solvent caused by contact of Ni 4+ with the solvent, and reduce damage of Ni 4+ to the SEI film, thereby improving the high-voltage stability and the cycle performance (particularly the cycle performance under high temperature and high voltage) of the battery.
In addition, the additive can be decomposed to form nitrogen-containing inorganic components with high plasma conductivity, such as methyl lithium (CH 3 Li) and lithium nitride (Li 3 N), in the electrochemical reaction process, and the nitrogen-containing inorganic components can enable interface impedance of the SEI film and the CEI film to be lower, so that the cycle performance of the battery is better improved, and the polarization degree of the battery, the multiplying power performance of the battery and the like are reduced; in addition, the SEI film containing the nitrogen-containing inorganic component has more stable structure and good ion conductivity, is favorable for uniform deposition of lithium ions on the surface of the negative electrode, reduces the forms of lithium dendrites and porous lithium, inhibits irreversible reaction caused by growth of the lithium dendrites, and improves the coulomb efficiency of the battery.
Therefore, the electrolyte has good high voltage resistance, less consumption of organic solvent under high voltage and less side reaction between the electrolyte and the positive electrode/negative electrode, and further the electrolyte can reduce gas production and volume expansion of the battery and improve the cycle performance, safety performance and coulombic efficiency of the battery. In addition, the fluorinated aromatic amide has good solubility in electrolyte solvents (particularly carbonate solvents), has less influence on the viscosity of the electrolyte when being added into the electrolyte, and provides a more effective way for introducing nitrogen-containing inorganic components with high ionic conductivity into SEI and CEI films.
In the present application, the substituted or unsubstituted aryl group may be either an aryl group having no ring heteroatom or a heteroaryl group having a ring heteroatom. Wherein the ring hetero atom may be one or more of nitrogen atom, oxygen atom, sulfur atom, selenium atom, boron atom, phosphorus atom, etc. In some embodiments of the application, the substituted or unsubstituted aryl group may comprise a substituted or unsubstituted phenyl group, or a substituted or unsubstituted fused ring aryl group. It will be appreciated that fused ring aryl groups may or may not contain ring heteroatoms.
Wherein the substituted or unsubstituted condensed ring aryl group may include one or more of a substituted or unsubstituted benzothienyl group, a substituted or unsubstituted benzofuranyl group, a substituted or unsubstituted benzopyrrolyl group, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted dibenzothienyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted anthryl group, a substituted or unsubstituted fluorenyl group, and a substituted or unsubstituted spirofluorenyl group, but is not limited thereto.
In some embodiments of the application, ar is substituted or unsubstituted phenyl. Under the condition, the additive shown in the formula (I) is easier to synthesize, and is easier to reduce at the negative electrode to form a stable SEI film with high ionic conductivity, so that the electrolyte containing the SEI film can ensure better battery cycle performance.
When Ar is a substituted or unsubstituted phenyl group, the additive represented by formula (I) may be represented by:
Wherein R 1、R2、R3、R4、R5 is independently selected from a hydrogen atom, or a substituent on a phenyl group. When R 1 to R 5 are each a hydrogen atom, ar is an unsubstituted phenyl group.
In an embodiment of the present application, the substituent in the substituted aryl group includes at least one of a halogen atom, a cyano group (-CN), an isothiocyano group (-NCS), an isocyanate group (-NCO), a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, and a substituted or unsubstituted aryl group. In the above formula (I-a), R 1、R2、R3、R4、R5 is independently selected from at least one of a hydrogen atom, a halogen atom, a cyano group (-CN), an isothiocyano group (-NCS), an isocyanato group (-NCO), a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, and a substituted or unsubstituted aryl group. Wherein the halogen atom includes one or more of fluorine atom (F), chlorine atom (Cl), bromine atom (Br), iodine atom (I). Cycloalkyl groups may or may not contain ring heteroatoms.
The introduction of different substituents in the aryl can obtain more structurally different additives of the formula (I), so that the adjustment of reduction potential/oxidation potential of the additives can be realized, and the requirements of different scenes can be met. In an embodiment of the application, the substituents in the substituted aryl groups do not include ester groups. The additive of the formula (I) does not contain ester groups, so that inorganic components with poor ion conductivity (such as Li 2 O, li 2CO3 and the like) are not formed in the electrochemical reaction process, but nitrogen-containing inorganic components with high ion conductivity such as methyl lithium (CH 3 Li) and lithium nitride (Li 3 N) are formed in a decomposition mode, and the impedance of SEI films and CEI films is reduced more favorably.
In an embodiment of the present application, the substituent groups in the substituted alkyl group, the substituted alkoxy group, the substituted alkenyl group, and the substituted alkynyl group are independently selected from at least one of a halogen atom, a cyano group (-CN), an isothiocyano group (-NCS), an isocyanate group (-NCO), a substituted or unsubstituted alkoxy group, and a substituted or unsubstituted aryl group; the substituent in the substituted cycloalkyl group and the substituted aryl group is independently selected from at least one of a halogen atom, a cyano group (-CN), an isothiocyano group (-NCS), an isocyanate group (-NCO), a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, and a substituted or unsubstituted aryl group.
In an embodiment of the present application, the substituted or unsubstituted alkyl group is a substituted or unsubstituted C 1～C10 alkyl group, and further may be a substituted or unsubstituted C 1～C6 alkyl group, a substituted or unsubstituted C 1～C4 alkyl group, or the like. Wherein the substituted or unsubstituted alkoxy is a substituted or unsubstituted C 1～C10 alkoxy, and further may be a substituted or unsubstituted C 1～C6 alkoxy, a substituted or unsubstituted C 1～C4 alkoxy, or the like. wherein the substituted or unsubstituted cycloalkyl is a substituted or unsubstituted C 3～C10 cycloalkyl, such as specifically substituted or unsubstituted cyclopentyl, substituted or unsubstituted cyclohexyl, and the like. Wherein the substituted or unsubstituted alkenyl group is a substituted or unsubstituted C 2～C10 alkenyl group, and further may be a substituted or unsubstituted C 2～C6 alkenyl group, a substituted or unsubstituted C 2～C4 alkenyl group, or the like. Wherein the substituted or unsubstituted alkynyl is a substituted or unsubstituted C 2～C10 alkynyl, and further may be a substituted or unsubstituted C 2～C6 alkynyl, a substituted or unsubstituted C 2～C4 alkynyl, or the like. Wherein the substituted or unsubstituted aryl is a substituted or unsubstituted C 6～C30 aryl, which may be a monocyclic aryl or a polycyclic aryl; Polycyclic aryl groups may be fused or non-fused (e.g., biphenyls). In some embodiments, the substituted or unsubstituted aryl group may be a substituted or unsubstituted C 6～C20 aryl group, a substituted or unsubstituted C 6～C12 aryl group, or the like. The carbon atoms of the alkyl, alkoxy, cycloalkyl, alkenyl, alkynyl and aryl which are substituted or unsubstituted are limited to a certain range, so that the solubility of the additive of the formula (I) in an organic solvent is proper, the viscosity of the electrolyte is within a proper range, and the wettability of the electrolyte containing the additive is not obviously influenced.
In some embodiments of the present application, the fluoroaromatic amide additive of formula (I) is selected from one or more of the following compounds:
Wherein the additive represented by the formula (i-1) may be referred to as 2, 2-fluoro-N-methyl-N-acetanilide. The additive represented by the formula (i-2) may be referred to as 2, 2-trifluoro-N- (4-isocyanatophenyl) -N-methylacetamide. The additive represented by the formula (i-3) may be referred to as 2, 2-trifluoro-N- (4-cyanophenyl) -N-methylacetamide. The additive represented by the formula (i-4) may be referred to as 2, 2-trifluoro-N- (3-fluorophenyl) -N-methylacetamide. The additive represented by the formula (i-5) may be referred to as 2, 2-trifluoro-N- (4-isothiocyanatophenyl) -N-methylacetamide. The additive represented by the formula (i-6) may be referred to as N- (3, 5-difluoro-4-allylphenyl) -2, 2-trifluoro-N-methylacetamide. The additive represented by the formula (i-7) may be referred to as N- (2-benzothienyl) -2, 2-trifluoro-N-methylacetamide.
In an embodiment of the application, the total mass percentage of the additive shown in the formula (I) in the electrolyte is 0.1-10%. The concentration of the additive shown in the formula (I) in the electrolyte is controlled within a proper range, so that SEI films and CEI films with proper thickness can be generated. Illustratively, the total mass percent of the additive of formula (I) in the electrolyte is 0.2%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, etc. In some embodiments, the total mass percent in the additive electrolyte of formula (I) is 3-8%. The additive can be used for forming SEI films and CEI films, so that capacity retention rate of high-voltage cycle of the battery is improved more effectively, the leaching amount of nickel element of the positive electrode is reduced, high-temperature storage stability is improved, and the problem that the performance of the battery is affected due to the fact that the SEI films and CEI films are too thick is avoided.
In some embodiments of the application, the electrolyte further comprises conventional film forming additives. Conventional film forming additives are mainly used for forming a solid electrolyte interface film on the surface of an electrode, and preventing side reactions of electrolysis and electrolyte. Wherein the conventional film-forming additive may include one or more of fluoroethylene carbonate (FEC), ethylene carbonate (VEC), vinylene Carbonate (VC), vinylene sulfite (ES), vinyl sulfate (DTD), and Methylene Methane Disulfonate (MMDS). The additive shown in the formula (I) in the embodiment of the application is added into an electrolyte system containing a conventional film-forming additive, and the matching effect of the two additives on an SEI film formed by a negative electrode is good. In some embodiments, the conventional film-forming additive is FEC. FEC can form a thin but stable SEI film with low resistance on the negative electrode surface.
In an embodiment of the present application, the mass percentage of the conventional film forming additive in the electrolyte is 0.1% -10%. Illustratively, the mass percent may be 0.2%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, etc. In some embodiments, the mass percent of conventional film-forming additives is preferably 3%. The interface stability between the battery electrode and the electrolyte can be improved well by a proper amount of conventional film forming additive.
In some embodiments of the application, the mass of the additive of formula (I) is 0.03 to 3.33 times the mass of the conventional film-forming additive. The two additives are matched in proper proportion to generate synergistic effect, and the synergistic effect can be superior to that of solvent to generate a more stable and compact SEI film on the surface of the negative electrode of the battery, thereby being more beneficial to improving the electrochemical performance, particularly the cycle performance, of the battery. Specifically, the additive shown in the formula (I) is 0.05, 0.17, 0.33, 0.67, 1, 1.33, 1.67, 2, 2.33, 2.67, 3, 3.2 and the like by mass of the conventional film forming additive. In some embodiments, the additive of formula (I) is 1-3 times the mass of the conventional film-forming additive, and further may be 1-2.67 times.
The additive shown in the formula (I) has the most remarkable effect of improving the tolerance of the electrolyte to high voltage (namely, being used as a high-voltage additive) and also has the effect of improving the film forming effect of the electrode interface film. In some embodiments of the application, other high pressure additives are also included in the electrolyte. Wherein the other high pressure additives include one or more of propylene sulfite (1, 3-Propylene Sulfite, PS), tripropynyl phosphate (TPP), tris (trimethylsilyl) phosphite (TMSP). The introduction of these additives also contributes to the stability of the above electrolyte at high voltages.
In an embodiment of the present application, the organic solvent in the electrolyte includes cyclic carbonates and linear carbonates. The cyclic carbonate has high dielectric constant and low viscosity, and the combination of the cyclic carbonate and the linear carbonate is favorable for improving the overall ionic conductivity of the electrolyte, and the cyclic carbonate can also participate in the formation of an SEI film, so that the occurrence of negative electrode side reaction is effectively prevented. In some embodiments of the application, the linear carbonate has a mass that is 1 to 2.5 times the mass of the cyclic carbonate. In this case, the electrolyte is more conducive to both the combined viscosity and good ionic conductivity.
Wherein the cyclic carbonate may include one or more of Ethylene Carbonate (EC), propylene Carbonate (PC), butylene carbonate, and the linear carbonate includes at least one of diethyl carbonate (DEC), dimethyl carbonate (DMC), and methyl ethyl carbonate (EMC). In some embodiments, the organic solvent is a mixture of EC and DEC in a mass ratio of 3:7, i.e., 1:2.3.
In an embodiment of the present application, the lithium salt in the above electrolyte includes lithium hexafluorophosphate (LiPF 6). Lithium hexafluorophosphate has a large LUMO-HOMO energy band, has strong chemical stability and oxidation resistance, and is low in price and most widely applied. The molar concentration of lithium hexafluorophosphate in the electrolyte may be 0.1mol/L to 1.2mol/L, for example, specifically 0.2mol/L, 0.5mol/L, 0.6mol/L, 0.8mol/L, 1.0mol/L, 1.1mol/L, etc. The LiPF 6 of a proper concentration is favorable for the exertion of the battery performance. In some embodiments, the molar concentration of LiPF 6 can be 1.0mol/L.
In some embodiments of the application, the lithium salt further comprises one or both of lithium bis-fluorosulfonyl imide (LiFSI) or lithium bis-trifluoromethanesulfonyl imide (LiTFSI). The two lithium salts have low fluorine content, are not easy to decompose to generate hydrofluoric acid, are used as further supplement to LiPF 6, can reduce the amount of hydrofluoric acid generated by the decomposition of the whole lithium salt, and are beneficial to improving the high temperature resistance of the electrolyte.
The first embodiment of the application also provides a lithium ion battery, which comprises the electrolyte provided by the embodiment of the application. The lithium ion battery containing the electrolyte has good high-voltage resistance, good high-temperature storage stability (low expansion degree of the battery at high temperature), good normal-temperature cycle performance, high-pressure cycle performance and the like.
The lithium ion battery can comprise a battery shell, a battery core accommodated in the battery shell and the electrolyte, wherein the battery core comprises a positive electrode plate, a negative electrode plate and a diaphragm positioned between the positive electrode plate and the negative electrode plate. The preparation method of the battery comprises the following steps: and sequentially stacking the positive electrode plate, the diaphragm and the negative electrode plate to prepare a battery core, accommodating the battery core in a battery shell, injecting the electrolyte, and sealing the battery shell to prepare the battery.
In the application, the negative pole piece, the positive pole piece and the diaphragm are all conventional choices in the field of batteries. The negative electrode plate comprises a negative electrode current collector and a negative electrode material layer arranged on the negative electrode current collector, wherein the negative electrode material layer can comprise a negative electrode active material, a binder and an optional conductive agent. Illustratively, the negative electrode active material includes, but is not limited to, artificial graphite, natural graphite, mesophase Carbon Microbeads (MCMB), silicon carbon materials, and the like. Similarly, the positive electrode tab includes a positive electrode current collector and a positive electrode material layer disposed on the positive electrode current collector. The positive electrode material layer includes a positive electrode active material, a binder, and optionally a conductive agent.
In some embodiments of the present application, the positive electrode active material may include a nickel-containing ternary material. Wherein, the structural general formula of the nickel-containing ternary material can be expressed as LiNi xCoyMzO2, x is more than or equal to 0.33 and less than or equal to 0.98,0< y <1,0< z <1, and x+y +z=1; m is at least one metal element from subgroup III to V, for example M is at least one selected from Mn, al, zr, ti, Y, sr and W, etc. When the value of x is higher, for example, x is more than or equal to 0.50 and less than or equal to 0.98, the nickel-containing ternary material can be called a high nickel ternary material, and the specific capacity of the high nickel ternary material is higher. Further, x may be in a range of 0.70.ltoreq.x.ltoreq.0.98, 0.70.ltoreq.x.ltoreq.0.90, 0.80.ltoreq.x.ltoreq.0.90, or 0.83.ltoreq.x.ltoreq.0.88, etc. In some embodiments, the nickel-containing ternary material is a nickel cobalt manganese ternary material (i.e., M is Mn, described above). Illustratively, the nickel-manganese-cobalt ternary material includes materials such as LiNi 0.33Co0.33Mn0.33O2 (abbreviated as NCM 111), LNi 0.4Co0.2Mn0.4O2 (abbreviated as NCM 424), liNi 0.5Co0.2Mn0.3O2 (abbreviated as NCM 523), liNi 0.6Co0.2Mn0.2O2 (abbreviated as NCM 622), liNi 0.8Co0.1Mn0.1O2 (abbreviated as NCM 811), liNi 0.85Co0.075Mn0.075O2, and the like.
It should be noted that the electrolyte provided in the embodiment of the present application may not be limited to a battery system in which the positive electrode is a ternary material containing nickel, but may also be applied to a lithium phosphate system (such as lithium iron phosphate, lithium manganese iron phosphate, etc.), a lithium cobalt oxide (LiCoO 2, LCO) system, a lithium nickel manganese oxide (LMNO) system, a lithium-rich manganese-based material system, etc.
The embodiment of the application also provides electric equipment, which comprises the lithium ion battery. The lithium ion battery can supply power for the electric equipment.
In the embodiment of the application, the electric equipment can be a 3C product (such as a mobile phone, a notebook computer, a tablet computer, a pen input type computer, an electronic book player, a wearable device and the like), or an electric vehicle (such as an electric automobile, an electric motorcycle, an electric bicycle and the like) and the like. In addition, the lithium ion battery provided by the embodiment of the application can also be used in an energy storage system.
The following examples are provided to further illustrate embodiments of the application.
Example 1
A preparation method of a lithium ion battery comprises the following steps:
(1) Preparing an electrolyte: 120g of Ethylene Carbonate (EC) and 280g of diethyl carbonate (DEC) are mixed to obtain a mixed solvent, 60g of lithium hexafluorophosphate (LiPF 6) is added to the mixed solvent to make the molar concentration of LiPF 6 be 1.0mol/L, and then 13.8g of film forming additive-fluoroethylene carbonate (FEC) and 23g of additive shown in the formula (i-1) are added, and the mixture is stirred until all solid matters are completely dissolved, so that the required electrolyte is obtained. Wherein the types and contents of the additives in the electrolyte are shown in table 1. The concentration of FEC in the electrolyte of example 1 was 3wt% and the concentration of the additive represented by formula (i-1) was 5wt%.
(2) Preparing a negative electrode plate: 100 parts of graphite material, 1 part of conductive agent Super-p,1.5 parts of thickener sodium carboxymethyl cellulose (CMC) and 2.5 parts of binder styrene-butadiene rubber (SBR) are mixed into uniform paste, and uniformly coated on a negative electrode current collector copper foil, and vacuum drying is carried out at 80 ℃ for 24 hours to obtain a negative electrode plate.
(3) Preparing a positive electrode plate: 100 parts by weight of ternary nickel manganese cobalt material LiNi 0.5Co0.2Mn0.3O2 (NCM 523), 2 parts of carbon nano tubes, 1 part of conductive agent Super-p and 2 parts of binder vinylidene fluoride (PVDF) are mixed into uniform paste, and uniformly coated on an anode current collector aluminum foil, and vacuum drying is carried out at 80 ℃ for 24 hours to obtain an anode plate.
(4) Assembling and forming a battery: and in an argon glove box with the water content less than 5ppm, sequentially stacking the positive electrode plate, the diaphragm and the negative electrode plate, winding the positive electrode plate, the diaphragm and the negative electrode plate into a bare cell, loading the bare cell into a battery shell, welding, and then injecting 1.6g of the electrolyte into the battery shell to seal the battery shell to prepare the soft-package lithium ion battery with the model SL 582736.
The soft package battery is formed by the following specific processes: the battery electrode sheet was first charged to 1.5V at a current of 40mA (0.05C) and held at 1.5V for 10 hours to allow adequate wetting. After the constant voltage was completed, the battery was initially charged at a small current of 8mA (C/100) for 10 hours to form a stable and dense SEI film, then charged at a current of 40mA (0.05C) to 4.35V, and then discharged to 3.0V.
Examples 2 to 11
Referring to the method of example 1, the electrolytes and lithium ion batteries of examples 2 to 11 were prepared in the proportions shown in table 1.
Comparative example 1
An electrolyte which differs from example 1 in that: the electrolyte does not contain film forming additive FEC and the fluoro aromatic amide additive provided by the application.
Referring to the method of example 1, the electrolyte of comparative example 1 was prepared into a lithium ion battery.
Comparative example 2
An electrolyte which differs from example 1 in that: the electrolyte does not contain the fluoro aromatic amide additive provided by the application.
Referring to the method of example 1, the electrolyte of comparative example 2 was prepared into a lithium ion battery.
Table 1 additive composition in each electrolyte
| Electrolyte numbering | Additive agent |
| Example 1 | 5Wt% of an additive of formula (I-1) and +3wt% of FEC |
| Example 2 | 5Wt% of an additive of formula (I-2) and +3wt% of FEC |
| Example 3 | 5Wt% of an additive of formula (I-3) and +3wt% of FEC |
| Example 4 | 5Wt% of an additive of formula (I-4) and +3wt% of FEC |
| Example 5 | 5Wt% of an additive of formula (I-5) and +3wt% of FEC |
| Example 6 | 5Wt% of an additive of formula (I-6) and +3wt% of FEC |
| Example 7 | 5Wt% of an additive of formula (I-7) and +3wt% of FEC |
| Example 8 | 3Wt% of an additive of formula (I-1) plus 3% FEC |
| Example 9 | 8Wt% of an additive of formula (I-1) plus 3% FEC |
| Example 10 | 10Wt% of an additive of formula (I-1) plus 3% FEC |
| Example 11 | 0.05Wt% of an additive of formula (I-1) plus 3% FEC |
| Comparative example 1 | Without any means for |
| Comparative example 2 | 3% FEC |
The lithium ion batteries prepared in examples 1 to 11 and comparative examples 1 to 2 were respectively subjected to the following performance tests:
(1) High temperature storage expansion rate test: and (3) charging each battery after formation at 0.5C, wherein the cut-off voltage is 4.5V, and stopping charging until the current is less than 0.02C at a constant voltage of 4.5V, thereby obtaining the full-charge battery. And (3) respectively placing all the batteries in a full-electricity state in a constant-temperature oven at 60 ℃ for 5 days, measuring the thicknesses of the batteries before and after storage by using a vernier caliper, subtracting the thickness of the batteries before storage from the thickness of the batteries after storage, and dividing the obtained thickness difference by the thickness of the batteries before storage to obtain the percentage of expansion of the batteries.
(2) And (3) testing the leaching amount of nickel: and disassembling the battery after the high-temperature expansion rate test is completed, taking out a negative electrode plate, soaking the negative electrode plate in a solvent DMC, airing the negative electrode plate, scraping powder, and sending the collected powder into an inductively coupled plasma spectrometer (Inductive coupled plasma emission spectrometer, ICP) of the Sieimer product for test to obtain the nickel content dissolved from the positive electrode to the negative electrode.
(3) And (3) testing high-voltage cycle performance of the battery: the air bags of the respective cells were subtracted and vacuum-sealed, and then placed in an incubator at 25 ℃, charge and discharge cycles were performed 300 times at a current of 1C between 2.75V and 4.5V, respectively, and the percentage obtained by dividing the discharge capacity of each cell at 300 th cycle by the initial discharge capacity at 1 st cycle was recorded as the capacity retention rate. The ratio of the discharge capacity to the charge capacity of each battery at the 1 st cycle was recorded as the first coulombic efficiency.
(4) And (3) testing direct current internal resistance of the battery: charging each battery after 300 times of circulation in the above (3) to 4.5V, discharging to 50% SOC, standing for 2h, measuring the instantaneous voltage U 1 of the battery at the last 1s of the above 2h, discharging for 30 seconds with a constant current I 0 of 1.5C, and measuring the instantaneous voltage U 2 of 30 seconds of discharging; the dc internal resistance (direct current INTERNAL RESISTANCE, DCIR) of the battery is calculated by the following formula: dcir= (U 1-U2)/I0.
Each of the above-described tests was performed on 10 batteries of each example or comparative example, and the test results of each group were an average value of 10 batteries and are summarized in table 2.
Table 2 results of performance test of each battery
As can be known from the comparison of examples 1-11 and comparative examples 1-2, the introduction of the fluoroaromatic amide additive of formula (I) provided by the embodiment of the application into the electrolyte can reduce the expansion rate of a full-charge battery during high-temperature storage, i.e. can improve the safety performance of the battery in a high-temperature environment; meanwhile, the nickel element can be effectively reduced from dissolving out from the positive electrode when the full-charge battery is stored at high temperature, the capacity retention rate of the battery in the circulating process of 4.5V full-charge high voltage is improved, and the service life of the battery is prolonged. In particular, the batteries of examples 1 to 10 also had higher initial coulombic efficiency at room temperature and lower DCIR value than the batteries of comparative examples 1 to 2.
Further, as is clear from the comparison between examples 1, 8 to 11, when the mass percentage of the additive represented by the formula (I) in the electrolyte is more than 0.05%, for example, in the range of 1 to 10%, the effect of improving each of the above-mentioned properties of the battery is more remarkable. Particularly, when the content of the additive is in the range of 3-8%, the battery can better give consideration to lower high-temperature storage expansion rate, lower positive electrode nickel element leaching amount and higher normal-temperature circulation capacity retention rate.
While the foregoing is directed to exemplary embodiments of the present application, it will be appreciated by those skilled in the art that various modifications and adaptations can be made thereto without departing from the principles of the present application, and such modifications and adaptations are intended to be comprehended within the scope of the present application.
Claims (14)
1. An electrolyte, characterized in that the electrolyte comprises a lithium salt, an organic solvent, and an additive represented by formula (I):
in formula (I), ar is selected from substituted or unsubstituted aryl.
2. The electrolyte of claim 1 wherein the substituted or unsubstituted aryl comprises a member selected from the group consisting of substituted or unsubstituted phenyl, and substituted or unsubstituted fused ring aryl;
wherein the substituted or unsubstituted fused ring aryl group comprises one or more of a substituted or unsubstituted benzothienyl group, a substituted or unsubstituted benzofuranyl group, a substituted or unsubstituted benzopyrrolyl group, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted dibenzothienyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted anthryl group, a substituted or unsubstituted fluorenyl group, and a substituted or unsubstituted spirofluorenyl group.
3. The electrolyte according to claim 1 or 2, wherein the substituent in the substituted aryl group comprises at least one of a halogen atom, a cyano group, an isothiocyano group, an isocyanato group, a substituted or unsubstituted C 1～C10 alkyl group, a substituted or unsubstituted C 1～C10 alkoxy group, a substituted or unsubstituted C 3～C10 cycloalkyl group, a substituted or unsubstituted C 2～C10 alkenyl group, a substituted or unsubstituted C 2～C10 alkynyl group, and a substituted or unsubstituted C 6～C30 aryl group.
4. The electrolyte of any one of claims 1 to 3, wherein the additive of formula (I) is selected from one or more of the following compounds:
5. the electrolyte according to any one of claims 1 to 4, wherein the additive represented by the formula (I) is present in the electrolyte in an amount of 0.1 to 10% by mass.
6. The electrolyte of any one of claims 1-5, wherein the electrolyte further comprises a conventional film-forming additive; wherein the conventional film forming additive comprises one or more of fluoroethylene carbonate, ethylene carbonate, vinylene sulfite, vinyl sulfate, and methylene methane disulfonate.
7. The electrolyte of claim 6 wherein the conventional film-forming additive is present in the electrolyte in an amount of 0.1% to 10% by mass.
8. The electrolyte of claim 6 wherein the mass of said additive of formula (I) is 0.03 to 3.33 times the mass of said conventional film-forming additive.
9. The electrolyte of any one of claims 1-8, further comprising a high pressure additive; wherein the high pressure additive comprises one or more of propylene sulfite, tripropylester phosphate and tri (trimethylsilyl) phosphite.
10. The electrolyte of claim 1 wherein the organic solvent comprises a cyclic carbonate and a linear carbonate; wherein the mass of the linear carbonate is 1 to 2.5 times the mass of the cyclic carbonate.
11. The electrolyte of claim 1 wherein the lithium salt comprises lithium hexafluorophosphate.
12. The electrolyte of claim 11 wherein the lithium salt further comprises one or more of lithium bis-fluorosulfonyl imide, lithium bis-trifluoromethanesulfonyl imide.
13. A lithium ion battery, characterized in that it comprises an electrolyte according to any one of claims 1-12.
14. A powered device comprising the lithium-ion battery of claim 13.
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