CN117423904A - Electrolyte and battery - Google Patents
Electrolyte and battery Download PDFInfo
- Publication number
- CN117423904A CN117423904A CN202311626966.1A CN202311626966A CN117423904A CN 117423904 A CN117423904 A CN 117423904A CN 202311626966 A CN202311626966 A CN 202311626966A CN 117423904 A CN117423904 A CN 117423904A
- Authority
- CN
- China
- Prior art keywords
- electrolyte
- additive
- lithium
- battery
- phosphate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000003792 electrolyte Substances 0.000 title claims abstract description 95
- 239000000654 additive Substances 0.000 claims abstract description 85
- 230000000996 additive effect Effects 0.000 claims abstract description 79
- -1 cyclic phosphate compound Chemical class 0.000 claims abstract description 58
- 239000003960 organic solvent Substances 0.000 claims abstract description 35
- 229910003002 lithium salt Inorganic materials 0.000 claims abstract description 33
- 159000000002 lithium salts Chemical class 0.000 claims abstract description 33
- 229910052731 fluorine Inorganic materials 0.000 claims abstract description 23
- 229910019142 PO4 Inorganic materials 0.000 claims abstract description 19
- 239000010452 phosphate Substances 0.000 claims abstract description 19
- 239000012948 isocyanate Substances 0.000 claims abstract description 15
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 8
- 125000004991 fluoroalkenyl group Chemical group 0.000 claims abstract description 7
- 125000003709 fluoroalkyl group Chemical group 0.000 claims abstract description 7
- 125000004178 (C1-C4) alkyl group Chemical group 0.000 claims abstract description 6
- 125000006656 (C2-C4) alkenyl group Chemical group 0.000 claims abstract description 6
- 125000006650 (C2-C4) alkynyl group Chemical group 0.000 claims abstract description 5
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 claims abstract description 5
- 150000004756 silanes Chemical class 0.000 claims abstract description 3
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 24
- 229910052744 lithium Inorganic materials 0.000 claims description 24
- 150000001875 compounds Chemical class 0.000 claims description 14
- 229910000077 silane Inorganic materials 0.000 claims description 13
- BTBUEUYNUDRHOZ-UHFFFAOYSA-N Borate Chemical compound [O-]B([O-])[O-] BTBUEUYNUDRHOZ-UHFFFAOYSA-N 0.000 claims description 8
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims description 8
- 150000002513 isocyanates Chemical class 0.000 claims description 6
- 239000005057 Hexamethylene diisocyanate Substances 0.000 claims description 5
- RRAMGCGOFNQTLD-UHFFFAOYSA-N hexamethylene diisocyanate Chemical compound O=C=NCCCCCCN=C=O RRAMGCGOFNQTLD-UHFFFAOYSA-N 0.000 claims description 5
- YZYKZHPNRDIPFA-UHFFFAOYSA-N tris(trimethylsilyl) borate Chemical compound C[Si](C)(C)OB(O[Si](C)(C)C)O[Si](C)(C)C YZYKZHPNRDIPFA-UHFFFAOYSA-N 0.000 claims description 5
- QJMMCGKXBZVAEI-UHFFFAOYSA-N tris(trimethylsilyl) phosphate Chemical compound C[Si](C)(C)OP(=O)(O[Si](C)(C)C)O[Si](C)(C)C QJMMCGKXBZVAEI-UHFFFAOYSA-N 0.000 claims description 5
- 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 5
- HKLZIJGDTNSHBI-UHFFFAOYSA-N C[SiH](C)C.N=C=O Chemical compound C[SiH](C)C.N=C=O HKLZIJGDTNSHBI-UHFFFAOYSA-N 0.000 claims description 4
- FSIJKGMIQTVTNP-UHFFFAOYSA-N bis(ethenyl)-methyl-trimethylsilyloxysilane Chemical compound C[Si](C)(C)O[Si](C)(C=C)C=C FSIJKGMIQTVTNP-UHFFFAOYSA-N 0.000 claims description 4
- 229910003473 lithium bis(trifluoromethanesulfonyl)imide Inorganic materials 0.000 claims description 4
- 229910001496 lithium tetrafluoroborate Inorganic materials 0.000 claims description 4
- QSZMZKBZAYQGRS-UHFFFAOYSA-N lithium;bis(trifluoromethylsulfonyl)azanide Chemical compound [Li+].FC(F)(F)S(=O)(=O)[N-]S(=O)(=O)C(F)(F)F QSZMZKBZAYQGRS-UHFFFAOYSA-N 0.000 claims description 4
- RBQRWNWVPQDTJJ-UHFFFAOYSA-N methacryloyloxyethyl isocyanate Chemical compound CC(=C)C(=O)OCCN=C=O RBQRWNWVPQDTJJ-UHFFFAOYSA-N 0.000 claims description 4
- WKWOFMSUGVVZIV-UHFFFAOYSA-N n-bis(ethenyl)silyl-n-trimethylsilylmethanamine Chemical compound C[Si](C)(C)N(C)[SiH](C=C)C=C WKWOFMSUGVVZIV-UHFFFAOYSA-N 0.000 claims description 4
- DGTNSSLYPYDJGL-UHFFFAOYSA-N phenyl isocyanate Chemical compound O=C=NC1=CC=CC=C1 DGTNSSLYPYDJGL-UHFFFAOYSA-N 0.000 claims description 4
- UFHILTCGAOPTOV-UHFFFAOYSA-N tetrakis(ethenyl)silane Chemical compound C=C[Si](C=C)(C=C)C=C UFHILTCGAOPTOV-UHFFFAOYSA-N 0.000 claims description 4
- DVKJHBMWWAPEIU-UHFFFAOYSA-N toluene 2,4-diisocyanate Chemical compound CC1=CC=C(N=C=O)C=C1N=C=O DVKJHBMWWAPEIU-UHFFFAOYSA-N 0.000 claims description 4
- ALQLPWJFHRMHIU-UHFFFAOYSA-N 1,4-diisocyanatobenzene Chemical compound O=C=NC1=CC=C(N=C=O)C=C1 ALQLPWJFHRMHIU-UHFFFAOYSA-N 0.000 claims description 3
- OVBFMUAFNIIQAL-UHFFFAOYSA-N 1,4-diisocyanatobutane Chemical compound O=C=NCCCCN=C=O OVBFMUAFNIIQAL-UHFFFAOYSA-N 0.000 claims description 3
- MHCFAGZWMAWTNR-UHFFFAOYSA-M lithium perchlorate Chemical compound [Li+].[O-]Cl(=O)(=O)=O MHCFAGZWMAWTNR-UHFFFAOYSA-M 0.000 claims description 3
- 229910001486 lithium perchlorate Inorganic materials 0.000 claims description 3
- HAMGRBXTJNITHG-UHFFFAOYSA-N methyl isocyanate Chemical compound CN=C=O HAMGRBXTJNITHG-UHFFFAOYSA-N 0.000 claims description 3
- 239000007983 Tris buffer Substances 0.000 claims description 2
- 229920002554 vinyl polymer Polymers 0.000 claims description 2
- 238000003860 storage Methods 0.000 abstract description 25
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 22
- 229910001416 lithium ion Inorganic materials 0.000 description 22
- 238000012360 testing method Methods 0.000 description 16
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 description 14
- 238000007599 discharging Methods 0.000 description 12
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 11
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 description 11
- 239000011737 fluorine Substances 0.000 description 11
- 230000014759 maintenance of location Effects 0.000 description 11
- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 description 8
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 description 8
- TWQULNDIKKJZPH-UHFFFAOYSA-K trilithium;phosphate Chemical compound [Li+].[Li+].[Li+].[O-]P([O-])([O-])=O TWQULNDIKKJZPH-UHFFFAOYSA-K 0.000 description 8
- 239000007789 gas Substances 0.000 description 7
- 229910001386 lithium phosphate Inorganic materials 0.000 description 7
- 239000007774 positive electrode material Substances 0.000 description 7
- 230000008901 benefit Effects 0.000 description 6
- 125000004432 carbon atom Chemical group C* 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 6
- 239000007773 negative electrode material Substances 0.000 description 6
- 102100028667 C-type lectin domain family 4 member A Human genes 0.000 description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 5
- 101000766908 Homo sapiens C-type lectin domain family 4 member A Proteins 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 5
- 238000000354 decomposition reaction Methods 0.000 description 5
- 125000001153 fluoro group Chemical group F* 0.000 description 5
- ZHPNWZCWUUJAJC-UHFFFAOYSA-N fluorosilicon Chemical compound [Si]F ZHPNWZCWUUJAJC-UHFFFAOYSA-N 0.000 description 5
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 4
- 125000000304 alkynyl group Chemical group 0.000 description 4
- 239000006227 byproduct Substances 0.000 description 4
- 230000007797 corrosion Effects 0.000 description 4
- 238000005260 corrosion Methods 0.000 description 4
- RTZKZFJDLAIYFH-UHFFFAOYSA-N ether Substances CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 4
- 230000006872 improvement Effects 0.000 description 4
- 238000002156 mixing Methods 0.000 description 4
- 239000002002 slurry Substances 0.000 description 4
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 description 3
- RJUFJBKOKNCXHH-UHFFFAOYSA-N Methyl propionate Chemical compound CCC(=O)OC RJUFJBKOKNCXHH-UHFFFAOYSA-N 0.000 description 3
- 125000003342 alkenyl group Chemical group 0.000 description 3
- 125000000217 alkyl group Chemical group 0.000 description 3
- 239000011230 binding agent Substances 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 239000006258 conductive agent Substances 0.000 description 3
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 description 3
- 150000002170 ethers Chemical class 0.000 description 3
- 230000002349 favourable effect Effects 0.000 description 3
- 230000002401 inhibitory effect Effects 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 229940017219 methyl propionate Drugs 0.000 description 3
- 238000007151 ring opening polymerisation reaction Methods 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 230000002195 synergetic effect Effects 0.000 description 3
- XCGWLSWJFSFGKT-UHFFFAOYSA-N tris[ethenyl(dimethyl)silyl] phosphate Chemical compound C=C[Si](C)(C)OP(=O)(O[Si](C)(C)C=C)O[Si](C)(C)C=C XCGWLSWJFSFGKT-UHFFFAOYSA-N 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- WNXJIVFYUVYPPR-UHFFFAOYSA-N 1,3-dioxolane Chemical compound C1COCO1 WNXJIVFYUVYPPR-UHFFFAOYSA-N 0.000 description 2
- YEJRWHAVMIAJKC-UHFFFAOYSA-N 4-Butyrolactone Chemical compound O=C1CCCO1 YEJRWHAVMIAJKC-UHFFFAOYSA-N 0.000 description 2
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 239000002033 PVDF binder Substances 0.000 description 2
- XBDQKXXYIPTUBI-UHFFFAOYSA-M Propionate Chemical compound CCC([O-])=O XBDQKXXYIPTUBI-UHFFFAOYSA-M 0.000 description 2
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 description 2
- HMDDXIMCDZRSNE-UHFFFAOYSA-N [C].[Si] Chemical compound [C].[Si] HMDDXIMCDZRSNE-UHFFFAOYSA-N 0.000 description 2
- 230000003044 adaptive effect Effects 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 239000006183 anode active material Substances 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 239000003575 carbonaceous material Substances 0.000 description 2
- 239000001768 carboxy methyl cellulose Substances 0.000 description 2
- 239000011889 copper foil Substances 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 230000006378 damage Effects 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- FKRCODPIKNYEAC-UHFFFAOYSA-N ethyl propionate Chemical compound CCOC(=O)CC FKRCODPIKNYEAC-UHFFFAOYSA-N 0.000 description 2
- 239000011888 foil Substances 0.000 description 2
- GAEKPEKOJKCEMS-UHFFFAOYSA-N gamma-valerolactone Chemical compound CC1CCC(=O)O1 GAEKPEKOJKCEMS-UHFFFAOYSA-N 0.000 description 2
- 239000010439 graphite Substances 0.000 description 2
- 229910002804 graphite Inorganic materials 0.000 description 2
- 125000001183 hydrocarbyl group Chemical group 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 2
- 150000003949 imides Chemical class 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- IQPQWNKOIGAROB-UHFFFAOYSA-N isocyanate group Chemical group [N-]=C=O IQPQWNKOIGAROB-UHFFFAOYSA-N 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- KKQAVHGECIBFRQ-UHFFFAOYSA-N methyl propyl carbonate Chemical compound CCCOC(=O)OC KKQAVHGECIBFRQ-UHFFFAOYSA-N 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 238000011056 performance test Methods 0.000 description 2
- 229910052698 phosphorus Inorganic materials 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 238000006467 substitution reaction Methods 0.000 description 2
- HHVIBTZHLRERCL-UHFFFAOYSA-N sulfonyldimethane Chemical compound CS(C)(=O)=O HHVIBTZHLRERCL-UHFFFAOYSA-N 0.000 description 2
- 125000002023 trifluoromethyl group Chemical group FC(F)(F)* 0.000 description 2
- 238000009966 trimming Methods 0.000 description 2
- 238000001291 vacuum drying Methods 0.000 description 2
- 238000003466 welding Methods 0.000 description 2
- 125000006002 1,1-difluoroethyl group Chemical group 0.000 description 1
- PEMRKDDXYZHSMU-UHFFFAOYSA-N 1-fluoro-2-(2-fluoroethoxy)ethane Chemical compound FCCOCCF PEMRKDDXYZHSMU-UHFFFAOYSA-N 0.000 description 1
- MHLLQRDUPCIDMR-UHFFFAOYSA-N 2-(2,2-difluoroethoxy)-1,1-difluoroethane Chemical compound FC(F)COCC(F)F MHLLQRDUPCIDMR-UHFFFAOYSA-N 0.000 description 1
- UPXMMKAMIKNCSS-UHFFFAOYSA-N 2-(trifluoromethylsulfonyl)propane Chemical compound CC(C)S(=O)(=O)C(F)(F)F UPXMMKAMIKNCSS-UHFFFAOYSA-N 0.000 description 1
- LJPCNSSTRWGCMZ-UHFFFAOYSA-N 3-methyloxolane Chemical compound CC1CCOC1 LJPCNSSTRWGCMZ-UHFFFAOYSA-N 0.000 description 1
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 1
- 229910013733 LiCo Inorganic materials 0.000 description 1
- 229910012851 LiCoO 2 Inorganic materials 0.000 description 1
- 229910011570 LiFe 1-x Inorganic materials 0.000 description 1
- 229910010707 LiFePO 4 Inorganic materials 0.000 description 1
- 229910015643 LiMn 2 O 4 Inorganic materials 0.000 description 1
- 229910014689 LiMnO Inorganic materials 0.000 description 1
- 229910002991 LiNi0.5Co0.2Mn0.3O2 Inorganic materials 0.000 description 1
- 239000004695 Polyether sulfone Substances 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 229920000388 Polyphosphate Polymers 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- ZJPPTKRSFKBZMD-UHFFFAOYSA-N [Li].FS(=N)F Chemical compound [Li].FS(=N)F ZJPPTKRSFKBZMD-UHFFFAOYSA-N 0.000 description 1
- OBNDGIHQAIXEAO-UHFFFAOYSA-N [O].[Si] Chemical class [O].[Si] OBNDGIHQAIXEAO-UHFFFAOYSA-N 0.000 description 1
- KXKVLQRXCPHEJC-UHFFFAOYSA-N acetic acid trimethyl ester Natural products COC(C)=O KXKVLQRXCPHEJC-UHFFFAOYSA-N 0.000 description 1
- DPXJVFZANSGRMM-UHFFFAOYSA-N acetic acid;2,3,4,5,6-pentahydroxyhexanal;sodium Chemical compound [Na].CC(O)=O.OCC(O)C(O)C(O)C(O)C=O DPXJVFZANSGRMM-UHFFFAOYSA-N 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 150000001408 amides Chemical class 0.000 description 1
- 239000004760 aramid Substances 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 229920003235 aromatic polyamide Polymers 0.000 description 1
- 239000002041 carbon nanotube Substances 0.000 description 1
- 229910021393 carbon nanotube Inorganic materials 0.000 description 1
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 1
- 150000007942 carboxylates Chemical class 0.000 description 1
- 150000001733 carboxylic acid esters Chemical class 0.000 description 1
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 1
- 238000003421 catalytic decomposition reaction Methods 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 230000010261 cell growth Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 150000005676 cyclic carbonates Chemical class 0.000 description 1
- 150000004292 cyclic ethers Chemical class 0.000 description 1
- 125000004122 cyclic group Chemical group 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
- 125000001028 difluoromethyl group Chemical group [H]C(F)(F)* 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 239000008151 electrolyte solution Substances 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- UGWBARXDYRKUDV-UHFFFAOYSA-N fluoro(fluoromethylsulfonyl)methane Chemical compound FCS(=O)(=O)CF UGWBARXDYRKUDV-UHFFFAOYSA-N 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 229910021385 hard carbon Inorganic materials 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000002905 metal composite material Substances 0.000 description 1
- 125000001570 methylene group Chemical group [H]C([H])([*:1])[*:2] 0.000 description 1
- 239000012046 mixed solvent Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 238000007344 nucleophilic reaction Methods 0.000 description 1
- 125000006340 pentafluoro ethyl group Chemical group FC(F)(F)C(F)(F)* 0.000 description 1
- 125000004437 phosphorous atom Chemical group 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 229920006393 polyether sulfone Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920006254 polymer film Polymers 0.000 description 1
- 229920000098 polyolefin Polymers 0.000 description 1
- 239000001205 polyphosphate Substances 0.000 description 1
- 235000011176 polyphosphates Nutrition 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
- 238000002360 preparation method Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000002153 silicon-carbon composite material Substances 0.000 description 1
- 235000019812 sodium carboxymethyl cellulose Nutrition 0.000 description 1
- 229920001027 sodium carboxymethylcellulose Polymers 0.000 description 1
- 229910021384 soft carbon Inorganic materials 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 229910000314 transition metal oxide Inorganic materials 0.000 description 1
- 150000003624 transition metals Chemical class 0.000 description 1
- 238000009461 vacuum packaging Methods 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
- PAPBSGBWRJIAAV-UHFFFAOYSA-N ε-Caprolactone Chemical compound O=C1CCCCCO1 PAPBSGBWRJIAAV-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
- H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
- H01M10/0566—Liquid materials
- H01M10/0567—Liquid materials characterised by the additives
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M2300/00—Electrolytes
- H01M2300/0017—Non-aqueous electrolytes
- H01M2300/0025—Organic electrolyte
-
- 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)
- Physics & Mathematics (AREA)
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Abstract
The invention provides an electrolyte and a battery, wherein the electrolyte comprises lithium salt, an organic solvent, a first additive and a second additive; the first additive includes a cyclic phosphate compound having a structure represented by formula 1, wherein R 1 、R 2 、R 3 、R 4 Each independently selected from H, F, phenyl, C1-C4 alkyl, C2-C4 alkenyl, C2-C4 alkynyl, C1-C4 fluoroalkyl, C2-C4 fluoroalkenyl, C2-C4 fluoroalkynyl, and n is 0-4; the second additive comprises isocyanate compounds and/or silane compounds. The electrolyte provided by the invention can reduce the impedance of the battery, so that the battery can improve the cycle, storage and safety performance under high and low temperature conditions.
Description
Technical Field
The invention relates to an electrolyte, in particular to an electrolyte and a battery, and belongs to the technical field of lithium ion batteries.
Background
In recent years, various portable electronic devices, new energy electric vehicles and energy storage systems have been rapidly developed and widely applied, and the demand for lithium ion batteries with high energy density, long cycle life, safe use and good multiplying power characteristics has been increasing.
However, since the electrolyte itself, the electrode/electrolyte interface, and the interfacial film generated by the electrolyte at the electrode surface in the lithium ion battery all cause an increase in the battery impedance, resulting in an increase in the electrochemical and concentration polarization of the battery, thereby deteriorating the electrochemical performance of the lithium ion battery under different temperature conditions.
In addition, when the lithium ion battery is applied in a high-temperature environment, the lithium ion battery is easy to have problems of aggravation of side reaction, gas production by decomposition of electrolyte and the like, and the high-temperature cycle performance, the high-temperature storage performance and the safety performance of the battery are deteriorated.
Therefore, there is a need to develop an electrolyte that is compatible with reducing battery impedance while optimizing capacity retention of the battery under low temperature conditions, cycle performance under normal and high temperature conditions, and storage and safety performance under high temperature conditions.
Disclosure of Invention
The present invention provides an electrolyte capable of reducing the impedance of a battery so that the battery can exhibit excellent low-temperature discharge performance, normal-temperature and high-temperature cycle performance, high-temperature storage performance and safety performance.
The invention provides a battery which has the advantages of long cycle life and high capacity retention rate under different temperature conditions, and has high storage performance and excellent safety performance under high temperature.
The invention provides an electrolyte, which comprises lithium salt, an organic solvent, a first additive and a second additive; the first additive includes a cyclic phosphate compound having a structure represented by formula 1:
wherein R is 1 、R 2 、R 3 、R 4 Each independently selected from H, F, phenyl, C1-C4 alkyl, C2-C4 alkenyl, C2-C4 alkynyl, C1-C4 fluoroalkyl, C2-C4 fluoroalkenyl, C2-C4 fluoroalkynyl, and n is 0-4;
the second additive comprises isocyanate compounds and/or silane compounds.
The electrolyte as described above, wherein the first additive includes a compound having a structure represented by formulas 2 to 5:
the electrolyte as described above, wherein the isocyanate-based compound includes at least one of methyl isocyanate, phenyl isocyanate, isocyanatoethyl methacrylate, tetramethylene diisocyanate, hexamethylene diisocyanate, p-phenylene diisocyanate, 2, 4-toluene diisocyanate, and trimethylsilane isocyanate; the silane compound comprises at least one of tetravinyl silane, divinyl tetramethyl disilazane, divinyl tetramethyl disiloxane, tris (trimethylsilyl) borate, tris (trimethylsilyl) phosphate, tris (trimethylsilyl) phosphite and tris (vinyl dimethyl silyl) phosphate.
The electrolyte comprises the first additive, wherein the mass percentage of the first additive in the electrolyte is 0.1-4%.
The electrolyte as described above, wherein the mass ratio of the first additive to the second additive is 1:0.2-2.
The electrolyte as described above, wherein the lithium salt comprises at least one of lithium hexafluorophosphate, lithium hexafluoroarsenate, lithium perchlorate, lithium tetrafluoroborate, lithium bisoxalato borate, lithium difluorooxalato borate, lithium difluorodioxaato phosphate, lithium tetrafluorooxalato phosphate, lithium bisfluorosulfonyl imide, and lithium bis (trifluoromethanesulfonyl) imide.
The electrolyte comprises the lithium salt, wherein the mass percentage of the lithium salt in the electrolyte is 7-20%.
The electrolyte comprises the organic solvent, wherein the mass percentage of the organic solvent in the electrolyte is 60-92%.
The electrolyte as described above, wherein the electrolyte comprises the following components in percentage by mass:
10-15% of lithium salt, 81-89% of organic solvent, 0.1-3% of first additive and 0.03-1% of second additive.
The invention also provides a battery comprising an electrolyte as described above.
The electrolyte provided by the invention limits the selection of the first additive and the second additive in the electrolyte, the first additive and the second additive cooperate to participate in constructing the interfacial film rich in fluorine-amide, fluorine-silicon, fluorine-containing lithium phosphate and other components, the electrolyte has the characteristics of uniform thickness, compact structure, corrosion resistance and high temperature stability, and the P=O bond is favorable for Li + The second additive helps to consume active oxygen, active hydrogen and H in the electrolyte 2 And O, the harm of impurity byproducts to the battery is reduced, and the low-temperature discharge performance, normal-temperature cycle performance, high-temperature storage performance and safety performance of the battery are further improved.
The battery of the present invention is prepared based on the electrolyte as described above, and has improved capacity retention under low temperature conditions, excellent cycle performance at normal and high temperatures, and high storage and safety properties at high temperatures.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the technical solutions in the embodiments of the present invention will be clearly and completely described in the following in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention provides an electrolyte, which comprises lithium salt, an organic solvent, a first additive and a second additive; the first additive includes a cyclic phosphate compound having a structure represented by formula 1:
wherein R is 1 、R 2 、R 3 、R 4 Each independently selected from H, F, phenyl, C1-C4 alkyl, C2-C4 alkenyl, C2-C4 alkynyl, C1-C4 fluoroalkyl, C2-C4 fluoroalkenyl, C2-C4 fluoroalkynyl, and n is 0-4; the second additive comprises isocyanate compound and/or silane compound.
The electrolyte of the invention comprises lithium salt and organic solvent, the invention does not limit the choice of lithium salt, as long as the electrolyte with stable and good lithium conducting performance can be prepared, for example, the lithium salt can be selected from lithium hexafluorophosphate, lithium difluorosulfimide, lithium bisoxalato borate, lithium tetrafluoroborate, lithium difluorooxalato borate, lithium bistrifluoromethylsulfonimide and the like; likewise, the choice of the organic solvent is not particularly limited in the present invention, as long as the lithium salt is completely dissolved to prepare a stable electrolyte, and for example, the organic solvent may be selected from carbonates, carboxylates, ethers, and the like.
The invention also includes a first additive and a second additive, the first additive being a cyclic phosphate compound, wherein R 1 、R 2 、R 3 、R 4 Each independently selected from H, F, phenyl, C1-C4 alkyl, C2-C4 alkenyl, C2-C4 alkynyl, C1-C4 fluoroalkyl, C2-C4 fluoroalkenyl, C2-C4 fluoroalkynyl, and n is 0-4. H, F of the present invention refers to a hydrogen atom and a fluorine atom. The C1-C4 alkyl group in the present invention means an alkyl group having 1 to 4 carbon atoms; C2-C4 alkenyl refers to alkenyl with 2-4 carbon atoms; the alkynyl of C2-C4 refers to alkynyl with 2-4 carbon atoms; C1-C4 fluoroalkyl means an alkyl group having 1 to 4 carbon atoms and having a fluorine atomThe method comprises the steps of carrying out a first treatment on the surface of the C2-C4 fluoroalkenyl refers to an alkenyl group having 2-4 carbon atoms and having a fluorine atom; C2-C4 fluoroalkynyl refers to an alkynyl group having 2-4 carbon atoms and having a fluorine atom; n is 0 to 4, meaning that 0 to 4 methylene groups are included in formula 1. When an alkyl, alkenyl or alkynyl group having a specific carbon number is specified, all geometric isomers having that carbon number are included. When R is 1 、R 2 、R 3 、R 4 When each is independently selected from the group consisting of a C1-C4 fluoroalkyl group, a C2-C4 fluoroalkenyl group, and a C2-C4 fluoroalkynyl group, any hydrogen atom in the hydrocarbon group may be substituted with a fluorine atom, and the number of substitution with a fluorine atom is not limited, for example, a monofluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a 1, 1-difluoroethyl group, a 1, 2-difluoroethyl group, a 2, 2-trifluoroethyl group, a pentafluoroethyl group 2, 3-tetrafluoropropyl, 2,2,2,3,3,3-hexafluoropropyl, 1, 3-hexafluoroisopropyl 2, 2-difluorovinyl, trifluorovinyl, 3-trifluoropropynyl, and the like.
The second additive of the present invention comprises an isocyanate-based compound and/or a silane-based compound. The isocyanate compound of the present invention is a compound having an isocyanate group (-n=c=o) in its molecular structure, and the isocyanate compound of the present invention is not particularly limited and may be selected from, for example, 2, 4-toluene diisocyanate, phenyl isocyanate, isocyanatoethyl methacrylate, trimethylsilane isocyanate, hexamethylene diisocyanate, and the like. The silane compound of the present invention is a compound containing a hydrocarbon substituent group with silicon as the center, and the silane compound of the present invention is not excessively selected, and may be selected from, for example, tetravinylsilane, divinyl tetramethyldisilazane, divinyl tetramethyldisiloxane, tris (trimethylsilyl) borate, tris (trimethylsilyl) phosphate, tris (trimethylsilyl) phosphite, tris (vinyldimethylsilyl) phosphate, and the like. Isocyanate-based compounds and/or silane-based compounds are generally used as high temperature type additives, which have a certain advantage in improving the high temperature performance of the battery, but isocyanate-based additives and silane-based additives have very significant drawbacks, namely, cause an increase in the battery resistance, and have negative effects on the low temperature discharge and high temperature resistance of the battery. The silane compound containing P or B, including tri (trimethylsilyl) borate, tri (trimethylsilyl) phosphate, tri (trimethylsilyl) phosphite and tri (vinyldimethylsilyl) phosphate, has relatively small impedance, but is very strict in water management and control of the battery core, and serious gas production is caused by a little careless, so that the influence on low temperature and high temperature performance of the battery is very serious, and even potential safety hazards are generated.
According to the scheme provided by the invention, after the electrolyte is applied to the lithium ion battery, the impedance of the lithium ion battery is low, and the low-temperature discharge performance, the cycle performance at normal temperature and high temperature, the high-temperature storage performance and the safety performance are excellent. The inventor analyzes the principle, and the cyclic phosphate compound has good improvement effect on the problem of increased battery impedance, has the advantage of preferential reaction relative to electrolyte solvent components due to lower reduction potential, wherein the five-membered cyclic structure is easy to participate in film formation through ring opening polymerization, and the introduced trifluoromethyl is favorable for generating a fluorine-containing lithium phosphate structure, so that the p=o bond rich in an interface film is endowed, and the electrolyte solution has excellent effects of reducing the impedance of the interface film and improving the stability of the battery; when the first additive and the second additive are compounded, the isocyanate groups or short-chain silane functional groups in the second additive can be utilized to consume active oxygen, active hydrogen and H in the electrolyte 2 O, reducing consumption and damage of these impurity byproducts to organic solvents, electrode interfacial film components, and electrode material structures in the electrolyte, the first additive may provide significant improvements in respect of the defect of increased resistance caused by the second additive; the two groups of additives are jointly participated in producing the interfacial film containing fluorine-amide, fluorine-silicon, fluorine-containing lithium phosphate and other components, so that the interfacial film has the characteristics of uniform film thickness, compact structure, corrosion resistance and high-temperature stability, wherein P=O bond contributes to Li + Has excellent effects of improving ionic conductivity of an interfacial film and reducing interface impedance of an electrode, and finally realizes high capacity retention, low battery impedance and little gas expansion of a battery under high and low temperature conditions; in addition, the central phosphorus atom of the cyclic phosphate compound reacts with TM-O of the positive electrode, so that the catalytic activity of the TM-O is reduced, and the excessive reaction in the positive electrode active material is inhibitedThe dissolution of the transition metal plays a very important role in improving the cycle and storage performance of the battery under high temperature conditions.
Comprehensive analysis proves that the first additive and the second additive have good synergistic effect, and have remarkable advantages in optimizing high-low temperature performance and improving overall performance of the battery.
In one embodiment, the first additive includes a compound having a structure represented by formulas 2-5:
the four compounds can more efficiently carry out ring-opening polymerization reaction to generate more stable fluorine-containing lithium phosphate, can more efficiently generate synergistic effect with the second additive to form a more stable and compact SEI film, and has good improvements in the aspects of reducing battery impedance, inhibiting electrolyte decomposition, improving battery capacity retention, inhibiting gas production and the like, and simultaneously can more easily carry out nucleophilic reaction with TM-O to reduce the catalytic decomposition of TM-O on the electrolyte, so that the battery has more excellent low-temperature discharge performance, normal-temperature cycle performance, high-temperature storage performance and safety performance.
In one embodiment, the isocyanate-based compound includes at least one of methyl isocyanate, phenyl isocyanate, isocyanatoethyl methacrylate, tetramethylene diisocyanate, hexamethylene diisocyanate, p-phenylene diisocyanate, 2, 4-toluene diisocyanate, and trimethylsilane isocyanate; the silane compound comprises at least one of tetravinyl silane, divinyl tetramethyl disilazane, divinyl tetramethyl disiloxane, tris (trimethylsilyl) borate, tris (trimethylsilyl) phosphate, tris (trimethylsilyl) phosphite and tris (vinyl dimethylsilyl) phosphate. When the isocyanate compound and the silane compound are selected from the above compounds, the synergistic reaction of the second additive and the cyclic phosphate compound is more efficient, and a more uniform, more compact and more stable SEI film of fluorine-amide, fluorine-silicon, fluorine-containing lithium phosphate and other components is generated, so that the impedance of the battery is reduced to a greater extent, and the problems of reaction of byproducts and organic solvents in the electrolyte and decomposition and gas production of the organic solvents can be suppressed to a greater extent, thereby further improving the low-temperature discharge, normal temperature/high temperature cycle performance, high temperature storage performance and safety performance of the battery.
In a specific embodiment, the first additive is present in the electrolyte in an amount of 0.1-4% by mass, i.e. 0.1-4 g of the first additive is included per hundred grams of electrolyte, and may specifically be selected from the group consisting of 0.1%, 0.2%, 0.5%, 1%, 2%, 4% or any two thereof. In the range, the first additive is more favorable for ring-opening polymerization to participate in film formation, the generated fluorine-containing lithium phosphate has good lithium ion conducting characteristic, the SEI film constructed by the first additive and the second additive is more uniform, compact and corrosion-resistant, the impedance of the battery can be reduced in the maximum extent, and the decomposition and gas production of the organic solvent are inhibited, so that the low-temperature discharge and normal-temperature/high-temperature cycle performance, the high-temperature storage performance and the safety performance of the battery are comprehensively improved.
In one embodiment, the mass ratio of the first additive to the second additive is 1:0.2-2. When the mass ratio of the first additive to the second additive is in the above range, the ratio of the components constituting the film of the cyclic phosphate compound to the isocyanate compound/silane compound is most balanced, and the increase in battery impedance due to the excessive amount of the second additive and the increase in by-products in the electrolyte due to the excessive amount of the organic fluorine component are not caused, and the stability of the electrolyte is not affected. The proportion of the two groups of additives is controlled to promote the two groups of additives to participate in constructing the interfacial film rich in fluorine-amide, fluorine-silicon, fluorine-containing lithium phosphate and other components, and the interfacial film has the characteristics of uniform thickness, compact structure, corrosion resistance and high-temperature stability, so that the capacity retention, impedance and safety performance of the battery under different temperature conditions have better improvement effects.
In one embodiment, the lithium salt comprises at least one of lithium hexafluorophosphate, lithium hexafluoroarsenate, lithium perchlorate, lithium tetrafluoroborate, lithium bisoxalato borate, lithium difluorooxalato borate, lithium difluorodioxaato phosphate, lithium tetrafluorooxalato phosphate, lithium bisfluorosulfonyl imide, lithium bis (trifluoromethanesulfonyl) imide. When the lithium salt is selected from the lithium salts, the lithium salts can fully play the role of the lithium salts, and the electrolyte with high ion conductivity and good stability is prepared, so that the lithium ion battery has excellent performance.
In a specific embodiment, the mass percentage of lithium salt in the electrolyte is 7-20%, i.e. 7-20 g of lithium salt is included in each hundred grams of electrolyte, and may specifically be selected from the range of 7%, 10%, 15%, 20% or any two thereof. When the mass percentage of the lithium salt is in the above range, the lithium salt can be completely and sufficiently dissolved in the electrolyte, so that the electrolyte can be more stable and has higher ionic conductivity, the viscosity of the electrolyte is moderate, and lithium ions can rapidly migrate in the electrolyte, so that the battery has better normal-temperature cycle performance, high-temperature cycle performance and high-temperature storage performance. Preferably, the mass percentage of the lithium salt in the electrolyte is 10-15%, and in the range, the lithium salt plays a larger role in the electrolyte, and the ionic conductivity of the electrolyte is higher, so that the low-temperature discharge performance, the normal-temperature cycle performance, the high-temperature cycle performance and the high-temperature storage performance of the battery are better.
In a specific embodiment, the mass percentage of the organic solvent in the electrolyte is 60-92%, i.e. 60-92 g of organic solvent is included in each hundred grams of electrolyte, and may specifically be selected from the range of 60%, 70%, 80%, 92% or any two thereof. When the organic solvent is in the above range, the organic solvent can sufficiently dissolve the lithium salt and the additive to prepare an electrolyte with high stability and high lithium conductivity, and the viscosity of the electrolyte is suitable to prepare an electrolyte with excellent electrochemical properties. Preferably, the mass percentage of the organic solvent in the electrolyte is 65-85%, and when the mass percentage of the organic solvent is within the range, the stability and the lithium guiding performance of the electrolyte are higher, and the viscosity is more suitable, so that the normal temperature cycle performance, the high temperature cycle performance and the high temperature storage performance of the electrolyte are better.
The present invention is not limited to a specific choice of the organic solvent, and the organic solvent may be any solvent commonly used in the art, for example, the organic solvent includes at least one of carbonate compounds, carboxylate compounds, ether compounds, and sulfone compounds. Wherein the carbonate compound comprises at least one of cyclic carbonates such as Ethylene Carbonate (EC), propylene Carbonate (PC) and linear carbonates such as dimethyl carbonate (DMC), ethylmethyl carbonate (EMC), diethyl carbonate (DEC) and methylpropyl carbonate (MPC); the carboxylic ester compound comprises at least one of cyclic carboxylic esters such as gamma-butyrolactone, gamma-valerolactone and epsilon-caprolactone and linear carboxylic esters such as methyl acetate, ethyl acetate, methyl propionate and ethyl propionate; the ether compound is at least one selected from chain ethers such as diethyl ether, di (2-fluoroethyl) ether, and di (2, 2-difluoroethyl) ether, and cyclic ethers such as tetrahydrofuran, 3-methyltetrahydrofuran, 1, 3-dioxolane, and 1, 4-dioxolane; the sulfone compound comprises at least one of dimethyl sulfone, fluoromethyl sulfone, trifluoromethyl isopropyl sulfone and other sulfone compounds.
In a preferred embodiment, the organic solvent comprises Ethylene Carbonate (EC), propylene Carbonate (PC), diethyl carbonate (DEC) and methyl propionate (PP), wherein the mass ratio of ethylene carbonate, propylene carbonate, diethyl carbonate and methyl propionate is 1 (1-10): 1-10. When the organic solvent is in the preferred range, the lithium salt, the first additive and the second additive are more adaptive to the organic solvent, so that the functions of the first additive and the second additive can be exerted to a greater extent, the impedance of the battery is further reduced, and the low-temperature discharge, the normal-temperature cycle performance, the high-temperature cycle performance and the high-temperature storage performance of the battery are further improved to a greater extent.
In a preferred embodiment, the organic solvent comprises Ethylene Carbonate (EC), diethyl carbonate (DEC) and ethylmethyl carbonate (EMC), wherein the mass ratio of ethylene carbonate, diethyl carbonate and ethylmethyl carbonate is 1 (0.1-10): 0.1-10. When the organic solvent is in this range, the lithium salt, the first additive and the second additive can exert their effects to a greater extent, so that the battery exhibits superior low-temperature discharge, normal-temperature cycle performance, high-temperature cycle performance and high-temperature storage performance.
In a preferred embodiment, the organic solvent comprises Ethylene Carbonate (EC), propylene Carbonate (PC) and Ethyl Methyl Carbonate (EMC), wherein the mass ratio of ethylene carbonate, propylene carbonate and ethyl methyl carbonate is 1 (0.1-10): 0.1-10. In this preferred range, the battery has lower impedance, and the lithium ion battery can exhibit better normal temperature cycle performance, high temperature cycle performance, and high temperature storage performance.
In one embodiment, the electrolyte comprises the following components in percentage by mass: 10-15% of lithium salt, 81-89% of organic solvent, 0.1-3% of first additive and 0.03-1% of second additive. When each component in the electrolyte is in the above range, the lithium salt, the first additive and the second additive are more adaptive, so that the generated SEI film is more compact and stable and has better lithium conducting performance, thereby reducing the impedance of the battery to a greater extent, further inhibiting the decomposition and gas production of the organic solvent, and further comprehensively improving the discharge performance, the cycle performance, the high-temperature storage performance and the safety performance of the battery under the high-low temperature condition.
The present invention is not limited to the method for preparing the electrolyte, and in one embodiment, the lithium salt, the organic solvent, the first additive, and the second additive may be mixed in a predetermined ratio.
The invention also provides a battery, which comprises the electrolyte. The battery has the advantages of low impedance, high low-temperature discharge rate, excellent normal temperature and high temperature cycle performance, long high-temperature storage time, low high-temperature expansion rate and the like.
In a specific embodiment, besides the electrolyte provided by the invention, the electrolyte further comprises a positive electrode plate, a negative electrode plate and a diaphragm, and specifically:
the positive electrode sheet comprises a positive electrode current collector and a positive electrode active material layer arranged on the surface of the positive electrode current collector, wherein the positive electrode active material layer comprises a positive electrode active material, a conductive agent and a binder, the positive electrode current collector is generally aluminum foil, and the positive electrode active material is selected from transition metal oxides of lithium, such as LiCoO 2 、LiMn 2 O 4 、LiMnO 2 、Li 2 MnO 4 、LiFePO 4 、Li 1+a Mn 1-x M x O 2 、LiCo 1-x M x O 2 、LiFe 1-x M x PO 4 、Li 2 Mn 1-x O 4 M is selected from one or more of Ni, co, mn, al, cr, mg, zr, mo, V, ti, B, F, a is more than or equal to 0 and less than or equal to 0.2, and x is more than or equal to 0<1。
The negative electrode sheet comprises a negative electrode current collector and a negative electrode active material layer arranged on the surface of the negative electrode current collector, wherein the negative electrode active material layer comprises a negative electrode active material, a conductive agent and a binder, the negative electrode current collector is generally copper foil, and the negative electrode active material is one or more selected from carbonaceous materials, silicon carbon materials, alloy materials and lithium-containing metal composite oxides, such as graphite, soft carbon, hard carbon, silicon-oxygen compounds, silicon-carbon composites, lithium titanate and the like.
The separator is a separator which is well known in the art, can be used in a battery and is stable to the electrolyte used, and may include one or more of polyolefin, aromatic polyamide, polytetrafluoroethylene, polyether sulfone, and may be specifically set as needed.
Hereinafter, the present invention will be described in further detail with reference to specific examples.
Example 1
The electrolyte provided by the implementation comprises: the lithium hexafluorophosphate comprises 12.5% by mass of lithium salt, wherein the organic solvent comprises ethylene carbonate, methyl ethyl carbonate and dimethyl carbonate, the mass ratio of the ethylene carbonate to the methyl ethyl carbonate is 1:1:1, the first additive is a cyclic phosphate compound shown as a formula 2, the mass percentage of the first additive is 0.5%, the second additive is hexamethylene diisocyanate, the mass percentage of the second additive is 0.05%, and the mass ratio of the first additive to the second additive is 1:0.1.
the preparation method of the electrolyte of the embodiment comprises the following steps: preparing electrolyte in a BRADN glove box, filling argon with the purity of 99.999%, controlling the water content in the glove box to be less than or equal to 0.1ppm, controlling the temperature in the glove box to be in a room temperature state, fully mixing ethylene carbonate, methyl ethyl carbonate and dimethyl carbonate, adding a first additive and a second additive, fully mixing, finally mixing lithium hexafluorophosphate in a mixed solvent, and uniformly mixing to obtain the electrolyte.
The electrolyte formulations provided in examples 2-30 and comparative examples 1-7 were substantially the same as in example 1, and the specific parameters are shown in Table 1.
TABLE 1 composition of electrolytes provided in examples 1 to 30 and comparative examples 1 to 7
Test example 1
The electrolytes provided in examples 1 to 30 and comparative examples 1 to 7 were prepared with positive electrode sheets, negative electrode sheets and separators to obtain lithium ion batteries, specifically: the positive electrode active material LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM 523), conductive carbon black SuperP, carbon nanotubes and PVDF (polyvinylidene fluoride) are dispersed in NMP according to the mass ratio of 96.3:2:0.5:1.2 to obtain anode active material layer slurry; uniformly coating the slurry of the positive electrode active material layer on the surface of an aluminum foil of a positive electrode current collector, drying at 85 ℃, cold pressing, trimming, cutting pieces, slitting, vacuum drying at 95 ℃ for 12 hours, and spot welding the tab to obtain a positive electrode plate with the surface density of 33mg/cm 2 。
Dispersing negative electrode active material graphite, conductive carbon black SuperP of a conductive agent, sodium carboxymethylcellulose (CMC) serving as a dispersing agent and SBR serving as a binding agent in deionized water according to a mass ratio of 95:1.5:1.5:2, and uniformly stirring to obtain negative electrode active material layer slurry; uniformly coating the slurry of the anode active material layer on the surface of the anode current collector copper foil, drying at 85 ℃, cold pressing, trimming, cutting, slitting, vacuum drying at 85 ℃ for 12 hours, and spot-welding the tab to obtain an anode pole piece with the surface density19.3mg/cm 2 。
And (3) selecting a polyethylene porous polymer film with the thickness of 16 mu m as a base material, and respectively coating polyvinylidene fluoride with the thickness of 2 mu m on two sides of the base material to obtain the diaphragm.
And sequentially stacking the prepared positive electrode plate, negative electrode plate and diaphragm, placing the diaphragm between the positive electrode plate and the negative electrode plate, winding to obtain a bare cell with a theoretical capacity of 1800mAh, placing the bare cell in an outer package, vacuum baking at 75 ℃ for 10 hours, injecting the electrolyte into the cell, and performing vacuum packaging, standing, formation, aging, capacity division and other procedures to prepare the lithium ion battery.
Test example 2
The lithium ion batteries including the electrolytes prepared in examples 1 to 30 and comparative examples 1 to 7 were subjected to battery performance tests as follows:
and (3) performing normal-temperature cycle test at 25 ℃: charging to 4.35V at 25deg.C under constant current of 1.0C, charging to off current of 0.05C under constant voltage of 4.35V, discharging the battery to 2.75V under constant current of 1.0C, repeating the charging and discharging steps for 1000 weeks, and testing to record discharge capacity C of 1000 th cycle 1000 And discharge capacity C at cycle 1 1 Cycle retention η at 25 ℃ 1 ＝C 1000 /C 1 *100％。
-10 ℃ low temperature discharge test: charging to 4.35V at 25deg.C under constant current of 1.0C, charging to off current of 0.05C under constant voltage of 4.35V, discharging to 2.75V under constant current of 0.5C, and recording discharge capacity as C 2 . Charging to 4.35V at 25deg.C constant current and constant voltage of 4.35V to cut-off current of 0.05C, transferring the battery to-10deg.C, standing for 240min, discharging to 2.75V at 0.5C constant current, and recording discharge capacity as C 3 Discharge capacity retention rate eta at-10 DEG C 2 ＝C 3 /C 2 *100％。
And (3) high-temperature cycle test at 45 ℃): charging to 4.35V at 45deg.C under constant current of 1.0C, charging to cut-off current of 0.05C under constant voltage of 4.35V, discharging the battery to 2.75V under constant current of 1.0C, repeating the charging and discharging steps for 600 weeks, and testing to record discharge capacity C of 600 th cycle 600 And cycle 1Discharge capacity C of (2) 4 Cycle retention η at 45 ℃ 3 ＝C 600 /C 4 *100％。
Storage test at 60℃for 30 days: charging to 4.35V at 25deg.C under constant current of 1.0C, charging to off current of 0.05C under constant voltage of 4.35V, discharging to 2.75V under constant current of 1.0C, and recording discharge capacity as C 5 . Charging to 4.35V at 25deg.C constant current, charging to off current of 0.05C at constant voltage of 4.35V, transferring to 60deg.C, standing for 30 days, discharging to 2.75V at 1.0C constant current, and recording discharge capacity as C 6 Capacity retention η at 60 ℃ for 30 days 4 ＝C 6 /C 5 *100％。
Initial DCIR test: charging the lithium ion battery to 4.35V at 25 ℃ with a constant current of 1.0C, charging the lithium ion battery to a cut-off current of 0.05C with a constant voltage of 4.35V, discharging the battery with a constant current of 1.0C for 30min, discharging with a constant current of 2.0C for 10s after the battery is placed for 1h, and calculating a DCIR impedance value of the battery under 50% SOC, wherein the recorded value is D 1 。
High temperature DCIR test: charging the lithium ion battery to 4.35V at 25 ℃ under a constant current of 1.0C, charging the lithium ion battery to a cut-off current of 0.05C under a constant voltage of 4.35V, discharging the battery for 30min under the constant current of 1.0C, discharging the battery for 10s under the constant current of 2.0C after the battery is placed for 1h, calculating DCIR (direct current) under the SOC of 50% of the battery, wherein the recorded value is D 2 . The battery which is subjected to the 60 ℃ high-temperature 30-day storage test is charged to 4.35V at the constant current of 1.0 ℃ at the temperature of 25 ℃, the constant voltage is charged to 0.05C at the constant voltage of 4.35V, then the battery is discharged for 30min at the constant current of 1.0 ℃, after the battery is placed for 1h, the battery is discharged for 10s at the constant current of 2.0C, the DCIR under the 50% SOC of the battery is calculated, and the record value is D 3 . Battery impedance change rate eta 5 ＝D 3 /D 2 *100％。
High temperature storage expansion rate test: charging the lithium ion battery to 4.35V at 25 ℃ with a constant current of 1.0C, charging the lithium ion battery to a cut-off current of 0.05C with a constant voltage of 4.35V, testing the thickness of the battery after the battery is charged, and recording the value as T 0 . The battery after the storage test at the high temperature of 60 ℃ for 30 days is subjected to the battery thickness test, and the recorded value is T 1 . Cell expansion ratio eta 6 ＝(T 1 -T 0 )/T 0 *100％。
The test results are shown in Table 2.
TABLE 2 results of Performance test of examples 1-30 and comparative examples 1-7
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As can be seen from table 2:
from comparison of examples 1 to 30 and comparative examples 1 to 7, it was confirmed that the interfacial film having a fluorine-containing lithium phosphate, a fluorine-containing amide/fluorine-silicon compound and a polyphosphate, which was constructed by reacting a cyclic phosphate compound with an isocyanate compound/silane compound, had excellent lithium ion conductive properties, and not only effectively reduced the impedance of the battery, suppressed the gassing phenomenon of the battery at high temperatures, and greatly improved the storage capacity retention of the battery at high temperatures and the cycle performance at normal and high temperatures.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.
Claims (10)
1. An electrolyte comprising a lithium salt, an organic solvent, a first additive, and a second additive; the first additive includes a cyclic phosphate compound having a structure represented by formula 1:
wherein R is 1 、R 2 、R 3 、R 4 Each independently selected from H, F, phenyl, C1-C4 alkyl, C2-C4 alkenyl, C2-C4 alkynyl, C1-C4 fluoroalkyl, C2-C4 fluoroalkenyl, C2-C4 fluoroalkynyl, and n is 0-4;
the second additive comprises isocyanate compounds and/or silane compounds.
2. The electrolyte of claim 1, wherein the first additive comprises a compound having a structure represented by formulas 2 to 5:
3. the electrolyte according to claim 1 or 2, wherein the isocyanate-based compound includes at least one of methyl isocyanate, phenyl isocyanate, isocyanatoethyl methacrylate, tetramethylene diisocyanate, hexamethylene diisocyanate, p-phenylene diisocyanate, 2, 4-toluene diisocyanate, and trimethylsilane isocyanate; the silane compound comprises at least one of tetravinyl silane, divinyl tetramethyl disilazane, divinyl tetramethyl disiloxane, tris (trimethylsilyl) borate, tris (trimethylsilyl) phosphate, tris (trimethylsilyl) phosphite and tris (vinyl dimethyl silyl) phosphate.
4. The electrolyte according to any one of claims 1 to 3, wherein the first additive is present in the electrolyte in an amount of 0.1 to 4% by mass.
5. The electrolyte of any one of claims 1-4 wherein the mass ratio of the first additive to the second additive is 1:0.2-2.
6. The electrolyte of any one of claims 1-5 wherein the lithium salt comprises at least one of lithium hexafluorophosphate, lithium hexafluoroarsenate, lithium perchlorate, lithium tetrafluoroborate, lithium bis (oxalato) borate, lithium difluorooxalato borate, lithium difluorodioxaato phosphate, lithium tetrafluorooxalato phosphate, lithium bis (trifluoromethanesulfonyl) imide, and lithium bis (trifluoromethanesulfonyl) imide.
7. The electrolyte according to any one of claims 1 to 6, wherein the mass percentage of the lithium salt in the electrolyte is 7 to 20%.
8. The electrolyte according to any one of claims 1 to 7, wherein the mass percentage of the organic solvent in the electrolyte is 60 to 92%.
9. The electrolyte according to any one of claims 1 to 8, wherein the electrolyte comprises, in mass percent:
10-15% of lithium salt, 81-89% of organic solvent, 0.1-3% of first additive and 0.03-1% of second additive.
10. A battery, characterized in that it comprises the electrolyte according to any one of claims 1-9.
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| CN117712488B (en) * | 2024-02-04 | 2024-05-24 | 深圳海辰储能科技有限公司 | Electrolyte, secondary battery containing same, battery pack and electric equipment |
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