CN117543109A - Lithium supplementing material, positive electrode plate, secondary battery and electronic equipment - Google Patents
Lithium supplementing material, positive electrode plate, secondary battery and electronic equipment Download PDFInfo
- Publication number
- CN117543109A CN117543109A CN202210924684.9A CN202210924684A CN117543109A CN 117543109 A CN117543109 A CN 117543109A CN 202210924684 A CN202210924684 A CN 202210924684A CN 117543109 A CN117543109 A CN 117543109A
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- CN
- China
- Prior art keywords
- lithium
- supplementing
- positive electrode
- battery
- supplementing material
- 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
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- 239000000463 material Substances 0.000 title claims abstract description 289
- 229910052744 lithium Inorganic materials 0.000 title claims abstract description 267
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 title claims abstract description 265
- 230000001502 supplementing effect Effects 0.000 title claims abstract description 194
- 239000000126 substance Substances 0.000 claims abstract description 8
- 239000002245 particle Substances 0.000 claims description 71
- 239000011149 active material Substances 0.000 claims description 49
- 239000003792 electrolyte Substances 0.000 claims description 19
- 239000007772 electrode material Substances 0.000 abstract description 6
- 230000006378 damage Effects 0.000 abstract description 4
- 238000000354 decomposition reaction Methods 0.000 description 64
- 238000012360 testing method Methods 0.000 description 64
- YNQRWVCLAIUHHI-UHFFFAOYSA-L dilithium;oxalate Chemical compound [Li+].[Li+].[O-]C(=O)C([O-])=O YNQRWVCLAIUHHI-UHFFFAOYSA-L 0.000 description 53
- 239000011259 mixed solution Substances 0.000 description 51
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 50
- 239000007774 positive electrode material Substances 0.000 description 44
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 description 42
- 230000000052 comparative effect Effects 0.000 description 39
- 239000010410 layer Substances 0.000 description 35
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 30
- -1 sulfate radical Chemical class 0.000 description 29
- 150000002500 ions Chemical class 0.000 description 24
- IIPYXGDZVMZOAP-UHFFFAOYSA-N lithium nitrate Chemical compound [Li+].[O-][N+]([O-])=O IIPYXGDZVMZOAP-UHFFFAOYSA-N 0.000 description 24
- 238000002156 mixing Methods 0.000 description 22
- 238000000034 method Methods 0.000 description 21
- 239000000203 mixture Substances 0.000 description 21
- 238000002360 preparation method Methods 0.000 description 19
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 18
- 150000001875 compounds Chemical class 0.000 description 18
- 239000007789 gas Substances 0.000 description 17
- 235000006408 oxalic acid Nutrition 0.000 description 16
- 229910052760 oxygen Inorganic materials 0.000 description 16
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 15
- 229910002651 NO3 Inorganic materials 0.000 description 15
- 239000006258 conductive agent Substances 0.000 description 15
- 229910001416 lithium ion Inorganic materials 0.000 description 15
- 239000002033 PVDF binder Substances 0.000 description 13
- 239000011230 binding agent Substances 0.000 description 13
- INHCSSUBVCNVSK-UHFFFAOYSA-L lithium sulfate Inorganic materials [Li+].[Li+].[O-]S([O-])(=O)=O INHCSSUBVCNVSK-UHFFFAOYSA-L 0.000 description 13
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 13
- RBTVSNLYYIMMKS-UHFFFAOYSA-N tert-butyl 3-aminoazetidine-1-carboxylate;hydrochloride Chemical compound Cl.CC(C)(C)OC(=O)N1CC(N)C1 RBTVSNLYYIMMKS-UHFFFAOYSA-N 0.000 description 13
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 12
- 239000011267 electrode slurry Substances 0.000 description 11
- 238000001704 evaporation Methods 0.000 description 11
- 238000000227 grinding Methods 0.000 description 11
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 10
- 239000006230 acetylene black Substances 0.000 description 10
- 230000015572 biosynthetic process Effects 0.000 description 10
- 238000004519 manufacturing process Methods 0.000 description 10
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 9
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 9
- 230000009286 beneficial effect Effects 0.000 description 9
- 229910017604 nitric acid Inorganic materials 0.000 description 9
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 description 8
- 229910012851 LiCoO 2 Inorganic materials 0.000 description 8
- 238000000576 coating method Methods 0.000 description 8
- 239000013078 crystal Substances 0.000 description 8
- 239000013543 active substance Substances 0.000 description 7
- 239000010405 anode material Substances 0.000 description 7
- 239000011248 coating agent Substances 0.000 description 7
- 238000010586 diagram Methods 0.000 description 7
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 6
- 239000002253 acid Substances 0.000 description 6
- 229910052799 carbon Inorganic materials 0.000 description 6
- 238000007599 discharging Methods 0.000 description 6
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- 239000013589 supplement Substances 0.000 description 6
- 230000009469 supplementation Effects 0.000 description 6
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 5
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 description 5
- 125000004432 carbon atom Chemical group C* 0.000 description 5
- 125000004122 cyclic group Chemical group 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 239000010408 film Substances 0.000 description 5
- YPJKMVATUPSWOH-UHFFFAOYSA-N nitrooxidanyl Chemical compound [O][N+]([O-])=O YPJKMVATUPSWOH-UHFFFAOYSA-N 0.000 description 5
- 125000004430 oxygen atom Chemical group O* 0.000 description 5
- 230000010287 polarization Effects 0.000 description 5
- 239000002904 solvent Substances 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- YEJRWHAVMIAJKC-UHFFFAOYSA-N 4-Butyrolactone Chemical compound O=C1CCCO1 YEJRWHAVMIAJKC-UHFFFAOYSA-N 0.000 description 4
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 4
- 229910002091 carbon monoxide Inorganic materials 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 description 4
- 229910021389 graphene Inorganic materials 0.000 description 4
- 239000011229 interlayer Substances 0.000 description 4
- 230000002427 irreversible effect Effects 0.000 description 4
- 229910003002 lithium salt Inorganic materials 0.000 description 4
- 159000000002 lithium salts Chemical class 0.000 description 4
- 239000012528 membrane Substances 0.000 description 4
- 125000004434 sulfur atom Chemical group 0.000 description 4
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 3
- 229910013872 LiPF Inorganic materials 0.000 description 3
- 101150058243 Lipf gene Proteins 0.000 description 3
- 239000004743 Polypropylene Substances 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 229910052786 argon Inorganic materials 0.000 description 3
- 239000002134 carbon nanofiber Substances 0.000 description 3
- 229910021393 carbon nanotube Inorganic materials 0.000 description 3
- 239000002041 carbon nanotube Substances 0.000 description 3
- 239000011889 copper foil Substances 0.000 description 3
- 150000004292 cyclic ethers Chemical class 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 230000002349 favourable effect Effects 0.000 description 3
- 239000011888 foil Substances 0.000 description 3
- 238000004817 gas chromatography Methods 0.000 description 3
- 229910002804 graphite Inorganic materials 0.000 description 3
- 239000010439 graphite Substances 0.000 description 3
- 230000002687 intercalation Effects 0.000 description 3
- 238000009830 intercalation Methods 0.000 description 3
- 238000004255 ion exchange chromatography Methods 0.000 description 3
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 3
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical class C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 3
- YQCIWBXEVYWRCW-UHFFFAOYSA-N methane;sulfane Chemical compound C.S YQCIWBXEVYWRCW-UHFFFAOYSA-N 0.000 description 3
- 238000011056 performance test Methods 0.000 description 3
- 229920001155 polypropylene Polymers 0.000 description 3
- 239000007784 solid electrolyte Substances 0.000 description 3
- 230000002195 synergetic effect Effects 0.000 description 3
- 238000001291 vacuum drying Methods 0.000 description 3
- VAYTZRYEBVHVLE-UHFFFAOYSA-N 1,3-dioxol-2-one Chemical compound O=C1OC=CO1 VAYTZRYEBVHVLE-UHFFFAOYSA-N 0.000 description 2
- JWUJQDFVADABEY-UHFFFAOYSA-N 2-methyltetrahydrofuran Chemical compound CC1CCCO1 JWUJQDFVADABEY-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 description 2
- XTHFKEDIFFGKHM-UHFFFAOYSA-N Dimethoxyethane Chemical compound COCCOC XTHFKEDIFFGKHM-UHFFFAOYSA-N 0.000 description 2
- 229910000733 Li alloy Inorganic materials 0.000 description 2
- 229910012820 LiCoO Inorganic materials 0.000 description 2
- 229910000572 Lithium Nickel Cobalt Manganese Oxide (NCM) Inorganic materials 0.000 description 2
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 2
- 229910019142 PO4 Inorganic materials 0.000 description 2
- 239000004952 Polyamide Substances 0.000 description 2
- 239000002174 Styrene-butadiene Substances 0.000 description 2
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 2
- YWJVFBOUPMWANA-UHFFFAOYSA-H [Li+].[V+5].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O Chemical compound [Li+].[V+5].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O YWJVFBOUPMWANA-UHFFFAOYSA-H 0.000 description 2
- 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 2
- 125000000129 anionic group Chemical group 0.000 description 2
- 239000001768 carboxy methyl cellulose Substances 0.000 description 2
- SBZXBUIDTXKZTM-UHFFFAOYSA-N diglyme Chemical compound COCCOCCOC SBZXBUIDTXKZTM-UHFFFAOYSA-N 0.000 description 2
- QHGJSLXSVXVKHZ-UHFFFAOYSA-N dilithium;dioxido(dioxo)manganese Chemical compound [Li+].[Li+].[O-][Mn]([O-])(=O)=O QHGJSLXSVXVKHZ-UHFFFAOYSA-N 0.000 description 2
- NKDDWNXOKDWJAK-UHFFFAOYSA-N dimethoxymethane Chemical compound COCOC NKDDWNXOKDWJAK-UHFFFAOYSA-N 0.000 description 2
- VUPKGFBOKBGHFZ-UHFFFAOYSA-N dipropyl carbonate Chemical compound CCCOC(=O)OCCC VUPKGFBOKBGHFZ-UHFFFAOYSA-N 0.000 description 2
- 239000002270 dispersing agent Substances 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 description 2
- 239000003365 glass fiber Substances 0.000 description 2
- 229910021385 hard carbon Inorganic materials 0.000 description 2
- 238000003475 lamination Methods 0.000 description 2
- 239000001989 lithium alloy Substances 0.000 description 2
- 229910000625 lithium cobalt oxide Inorganic materials 0.000 description 2
- MHCFAGZWMAWTNR-UHFFFAOYSA-M lithium perchlorate Chemical compound [Li+].[O-]Cl(=O)(=O)=O MHCFAGZWMAWTNR-UHFFFAOYSA-M 0.000 description 2
- 229910001486 lithium perchlorate Inorganic materials 0.000 description 2
- 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 2
- ILXAVRFGLBYNEJ-UHFFFAOYSA-K lithium;manganese(2+);phosphate Chemical compound [Li+].[Mn+2].[O-]P([O-])([O-])=O ILXAVRFGLBYNEJ-UHFFFAOYSA-K 0.000 description 2
- BFZPBUKRYWOWDV-UHFFFAOYSA-N lithium;oxido(oxo)cobalt Chemical compound [Li+].[O-][Co]=O BFZPBUKRYWOWDV-UHFFFAOYSA-N 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 239000011572 manganese Substances 0.000 description 2
- KKQAVHGECIBFRQ-UHFFFAOYSA-N methyl propyl carbonate Chemical compound CCCOC(=O)OC KKQAVHGECIBFRQ-UHFFFAOYSA-N 0.000 description 2
- 125000004433 nitrogen atom Chemical group N* 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 2
- 239000010452 phosphate Substances 0.000 description 2
- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 2
- 229920000058 polyacrylate Polymers 0.000 description 2
- 229920002239 polyacrylonitrile Polymers 0.000 description 2
- 229920002647 polyamide Polymers 0.000 description 2
- 239000004926 polymethyl methacrylate Substances 0.000 description 2
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 2
- 239000004810 polytetrafluoroethylene Substances 0.000 description 2
- 229920001289 polyvinyl ether Polymers 0.000 description 2
- 239000001267 polyvinylpyrrolidone Substances 0.000 description 2
- 229920000036 polyvinylpyrrolidone Polymers 0.000 description 2
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 description 2
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 description 2
- 238000004445 quantitative analysis Methods 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 235000019812 sodium carboxymethyl cellulose Nutrition 0.000 description 2
- 229920001027 sodium carboxymethylcellulose Polymers 0.000 description 2
- 229910021384 soft carbon Inorganic materials 0.000 description 2
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 2
- LSGOVYNHVSXFFJ-UHFFFAOYSA-N vanadate(3-) Chemical compound [O-][V]([O-])([O-])=O LSGOVYNHVSXFFJ-UHFFFAOYSA-N 0.000 description 2
- 125000005287 vanadyl group Chemical group 0.000 description 2
- SPEUIVXLLWOEMJ-UHFFFAOYSA-N 1,1-dimethoxyethane Chemical compound COC(C)OC SPEUIVXLLWOEMJ-UHFFFAOYSA-N 0.000 description 1
- LEEANUDEDHYDTG-UHFFFAOYSA-N 1,2-dimethoxypropane Chemical compound COCC(C)OC LEEANUDEDHYDTG-UHFFFAOYSA-N 0.000 description 1
- WNXJIVFYUVYPPR-UHFFFAOYSA-N 1,3-dioxolane Chemical compound C1COCO1 WNXJIVFYUVYPPR-UHFFFAOYSA-N 0.000 description 1
- XKTYXVDYIKIYJP-UHFFFAOYSA-N 3h-dioxole Chemical compound C1OOC=C1 XKTYXVDYIKIYJP-UHFFFAOYSA-N 0.000 description 1
- ZZLCFHIKESPLTH-UHFFFAOYSA-N 4-Methylbiphenyl Chemical compound C1=CC(C)=CC=C1C1=CC=CC=C1 ZZLCFHIKESPLTH-UHFFFAOYSA-N 0.000 description 1
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- BTBUEUYNUDRHOZ-UHFFFAOYSA-N Borate Chemical compound [O-]B([O-])[O-] BTBUEUYNUDRHOZ-UHFFFAOYSA-N 0.000 description 1
- 239000006245 Carbon black Super-P Substances 0.000 description 1
- 229910000846 In alloy Inorganic materials 0.000 description 1
- 229910000799 K alloy Inorganic materials 0.000 description 1
- 229910015013 LiAsF Inorganic materials 0.000 description 1
- 229910013075 LiBF Inorganic materials 0.000 description 1
- 229910013528 LiN(SO2 CF3)2 Inorganic materials 0.000 description 1
- 229910013024 LiNi0.5Mn1.5O2 Inorganic materials 0.000 description 1
- 229910013870 LiPF 6 Inorganic materials 0.000 description 1
- 229910000528 Na alloy Inorganic materials 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 229910000676 Si alloy Inorganic materials 0.000 description 1
- 229910001128 Sn alloy Inorganic materials 0.000 description 1
- 229920002125 Sokalan® Polymers 0.000 description 1
- CKUAXEQHGKSLHN-UHFFFAOYSA-N [C].[N] Chemical compound [C].[N] CKUAXEQHGKSLHN-UHFFFAOYSA-N 0.000 description 1
- JFBZPFYRPYOZCQ-UHFFFAOYSA-N [Li].[Al] Chemical compound [Li].[Al] JFBZPFYRPYOZCQ-UHFFFAOYSA-N 0.000 description 1
- ZVLDJSZFKQJMKD-UHFFFAOYSA-N [Li].[Si] Chemical compound [Li].[Si] ZVLDJSZFKQJMKD-UHFFFAOYSA-N 0.000 description 1
- FBDMTTNVIIVBKI-UHFFFAOYSA-N [O-2].[Mn+2].[Co+2].[Ni+2].[Li+] Chemical compound [O-2].[Mn+2].[Co+2].[Ni+2].[Li+] FBDMTTNVIIVBKI-UHFFFAOYSA-N 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 150000001450 anions Chemical class 0.000 description 1
- 229910021383 artificial graphite Inorganic materials 0.000 description 1
- 125000004429 atom Chemical group 0.000 description 1
- MTAZNLWOLGHBHU-UHFFFAOYSA-N butadiene-styrene rubber Chemical compound C=CC=C.C=CC1=CC=CC=C1 MTAZNLWOLGHBHU-UHFFFAOYSA-N 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 230000001186 cumulative effect Effects 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 239000011263 electroactive material Substances 0.000 description 1
- 238000000921 elemental analysis Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- NBVXSUQYWXRMNV-UHFFFAOYSA-N fluoromethane Chemical compound FC NBVXSUQYWXRMNV-UHFFFAOYSA-N 0.000 description 1
- LHJOPRPDWDXEIY-UHFFFAOYSA-N indium lithium Chemical compound [Li].[In] LHJOPRPDWDXEIY-UHFFFAOYSA-N 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 239000003273 ketjen black Substances 0.000 description 1
- 239000004816 latex Substances 0.000 description 1
- 229920000126 latex Polymers 0.000 description 1
- 150000002641 lithium Chemical class 0.000 description 1
- AMXOYNBUYSYVKV-UHFFFAOYSA-M lithium bromide Chemical compound [Li+].[Br-] AMXOYNBUYSYVKV-UHFFFAOYSA-M 0.000 description 1
- KWGKDLIKAYFUFQ-UHFFFAOYSA-M lithium chloride Chemical compound [Li+].[Cl-] KWGKDLIKAYFUFQ-UHFFFAOYSA-M 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
- OBTSLRFPKIKXSZ-UHFFFAOYSA-N lithium potassium Chemical compound [Li].[K] OBTSLRFPKIKXSZ-UHFFFAOYSA-N 0.000 description 1
- VVNXEADCOVSAER-UHFFFAOYSA-N lithium sodium Chemical compound [Li].[Na] VVNXEADCOVSAER-UHFFFAOYSA-N 0.000 description 1
- 229910001496 lithium tetrafluoroborate Inorganic materials 0.000 description 1
- UIDWHMKSOZZDAV-UHFFFAOYSA-N lithium tin Chemical compound [Li].[Sn] UIDWHMKSOZZDAV-UHFFFAOYSA-N 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910021382 natural graphite Inorganic materials 0.000 description 1
- 239000007773 negative electrode material Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 150000002895 organic esters Chemical class 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920000139 polyethylene terephthalate Polymers 0.000 description 1
- 239000005020 polyethylene terephthalate Substances 0.000 description 1
- 229920000098 polyolefin Polymers 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
- 239000011115 styrene butadiene Substances 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- BDHFUVZGWQCTTF-UHFFFAOYSA-M sulfonate Chemical compound [O-]S(=O)=O BDHFUVZGWQCTTF-UHFFFAOYSA-M 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 150000008053 sultones Chemical class 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—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
- 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
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/136—Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
- H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/621—Binders
- H01M4/622—Binders being polymers
- H01M4/623—Binders being polymers fluorinated polymers
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/624—Electric conductive fillers
- H01M4/625—Carbon or graphite
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Abstract
The application provides a lithium supplementing material, a positive electrode plate, a secondary battery and electronic equipment, wherein the lithium supplementing material comprises a chemical formula of Li 2 (C 2 O 4 ) a (SO 4 ) b (NO 3 ) c Wherein a+b+0.5c=1, 0 < a < 1, b.gtoreq.0, c.gtoreq.0. The lithium supplementing material has a lower lithium removing potential, and can remove active lithium under a low potential, so that the active lithium consumed during primary charging is supplemented, the damage of high-voltage charging to the electrode material structure is avoided, and the capacity and the cycle performance of the battery are improved.
Description
Technical Field
The application relates to the technical field of secondary batteries, in particular to a lithium supplementing material, a positive electrode plate, a secondary battery and electronic equipment.
Background
Lithium secondary batteries have been widely used in end products (smart phones, digital cameras, notebook computers, electric vehicles, etc.) due to their high energy density, high operating voltage, long service life, low self-discharge rate, environmental friendliness, and the like.
During the first charge of a lithium secondary battery, the formation of a solid electrolyte film (SEI) on the surface of the negative electrode consumes a large amount of active lithium, resulting in a decrease in the first coulombic efficiency and capacity of the battery, and thus lithium supplementation of the lithium secondary battery is required. However, the existing lithium supplementing material has higher lithium removing potential, is only suitable for a high-voltage lithium ion battery system, and can cause irreversible change of the structure of an electrode material due to higher charging voltage for a common lithium ion battery, so that the structural stability of the electrode material and the cycle performance of the battery are reduced. Therefore, it is necessary to develop a lithium supplementing material having a low lithium removal potential to reduce the damage of high voltage to the electrode material and to extend the service life of the battery.
Disclosure of Invention
In view of this, this application provides a lithium supplementing material, and this lithium supplementing material has lower delithiation potential, can deviate from active lithium under low potential to the active lithium who consumes when supplementing first charge avoids the destruction of high voltage charging to electrode material structure, improves the capacity and the cycle performance of battery.
The first aspect of the present application provides a lithium supplementing material comprising a compound of formula Li 2 (C 2 O 4 ) a (SO 4 ) b (NO 3 ) c Wherein a+b+0.5c=1, 0 < a < 1, b.gtoreq.0, c.gtoreq.0.
According to the lithium oxalate material, a certain amount of doping ions (sulfate radical and/or nitrate radical) are added into the lithium oxalate, so that the crystal layer spacing of the lithium oxalate can be enlarged, the crystal structure of the lithium oxalate becomes loose, the intermolecular acting force is reduced, the polarization voltage required by the decomposition of the lithium supplementing material is reduced, the lithium removing potential of the lithium supplementing material is reduced, and the lithium supplementing under low charging voltage is realized.
Optionally, the ratio of a to (b+0.5c) is greater than or equal to 9.
Alternatively, b > 0 and c > 0.
Optionally, 0 < b < c.
Alternatively, 1 < c/b < 10.
Optionally, the particle size of the lithium supplementing material is 1 nm-20 μm.
Optionally, the particle size of the lithium supplementing material is 0.1-5 μm.
In a second aspect, the present application provides a positive electrode sheet comprising an active material and a lithium supplementing material as described in the first aspect of the present application.
Optionally, the positive electrode sheet includes a current collector and an active material layer disposed on the current collector, and the active material layer includes the active material and the lithium supplementing material.
Optionally, the positive electrode plate includes a current collector, a positive electrode material layer and a lithium supplementing layer which are sequentially arranged, the positive electrode material layer includes the active material, and the lithium supplementing layer includes the lithium supplementing material.
Optionally, the mass ratio of the lithium supplementing material to the active material is 1 (5-1000).
Optionally, the mass ratio of the lithium supplementing material to the active material is 1 (10-100).
Optionally, the mass ratio of the lithium supplementing material to the active material is 1 (20-50).
Optionally, the active material includes one or more of lithium iron phosphate, lithium cobalt oxide, lithium manganate, ternary materials, lithium manganese phosphate, lithium manganese iron phosphate, lithium vanadium phosphate, lithium vanadyl phosphate, lithium vanadate, and lithium-rich manganese-based materials.
Optionally, the active material layer contains 80% -99.9% of active material by mass.
Optionally, the mass percentage of the lithium supplementing material in the active material layer is 0.1% -15%.
Optionally, the active material layer further includes a conductive agent and a binder.
Optionally, the binder comprises one or more of polyvinylidene fluoride, polytetrafluoroethylene, polyhexafluoropropylene, styrene-butadiene rubber, sodium carboxymethyl cellulose, polyvinylpyrrolidone, polyvinyl ether, polymethyl methacrylate, polyamide, polyacrylonitrile, and polyacrylate.
Optionally, the conductive agent includes one or more of acetylene black, carbon nanotubes, carbon nanofibers, activated carbon, and graphene.
In a third aspect, the present application provides a secondary battery comprising a positive electrode, a negative electrode, a separator and an electrolyte, wherein the positive electrode comprises a positive electrode sheet according to the second aspect of the present application.
In a fourth aspect, the present application provides an electronic device, including the positive electrode sheet according to the third aspect of the present application.
Drawings
Fig. 1 is a schematic view of a secondary battery according to an embodiment of the present application;
fig. 2 is a charge-discharge graph of the test cells of examples 1-4;
FIG. 3 is a charge-discharge graph of the test cells of examples 6-9;
FIG. 4 is a charge-discharge graph of the test cells of examples 11-13;
FIG. 5 is a charge-discharge graph of the test cells of comparative examples 1-2;
fig. 6 is a graph showing the cycle performance of the secondary battery S1 of example 14 and the secondary battery DS1 of comparative example 1;
Fig. 7 is a graph showing the cycle performance of the secondary battery S8 of example 21 and the secondary battery DS1 of comparative example 1;
fig. 8 is a graph showing the cycle performance of the secondary battery S15 of example 28 and the secondary battery DS1 of comparative example 1;
fig. 9 is a gas production comparison diagram of the secondary battery S1 of example 14 and the secondary battery DS1 of comparative example 1;
fig. 10 is a gas production comparison chart of the secondary battery S8 of example 21 and the secondary battery DS1 of comparative example 1;
fig. 11 is a gas production comparison diagram of the secondary battery S15 of example 28 and the secondary battery DS1 of comparative example 1.
Detailed Description
The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by one of ordinary skill in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application.
Existing lithium supplementing materials such as lithium oxalate (Li 2 C 2 O 4 ) The decomposition lithium removal voltage is as high as 4.7V, and is only suitable for high-voltage lithium ion battery systems, such as high-voltage positive electrode material LiNi 0.5 Mn 1.5 O 2 The operating voltage of the (lithium nickel manganese oxide) is 4.7-4.8V. However, for most positive electrode materials, the decomposition lithium removal voltage value of 4.7V of the lithium supplementing material is far from the charging cut-off voltage of Gao Yuzheng electrode materials, and the higher the charging voltage is, the larger the irreversible change of the positive electrode material structure is, the lower the structural stability of the positive electrode material is, and the cycle performance of the battery is poor; however, if the battery is charged at a lower potential, the lithium supplementing material cannot fully remove lithium, so that the lithium supplementing effect is poor, the coulomb efficiency of the first charge of the battery is lower, and the capacity of the battery is not facilitated; in addition, as lithium oxalate is unlikely to react completely in the formation process, in some high-voltage battery systems, unreacted lithium oxalate is easy to react and generate gas in the subsequent cycle process, and the safety performance of the battery is reduced. In this regard, the present application provides a lithium supplementing material having a low decomposition potential, which is suitable for most of the current positive electrode materials, and is beneficial to realizing effective lithium supplementation of a battery, thereby improving the capacity and cycle performance of the battery.
The lithium supplementing material provided by the application comprises a chemical formula of Li 2 (C 2 O 4 ) a (SO 4 ) b (NO 3 ) c Wherein a+b+0.5c=1, i.e. the anionic composition satisfies the charge neutrality principle, 0 < a < 1, b.gtoreq.0, c.gtoreq.0, and b and c are not simultaneously 0. In the lithium supplementing material, ion NO is doped 3 - And/or SO 4 2- Contains arc inOxygen atom to electron and C 2 O 4 2- Has electrostatic force between carbon atoms polarized by oxygen atoms, so that the doping ions are in Li 2 C 2 O 4 Is inserted between layers, doping oxygen atoms and C in the ion 2 O 4 2- Has electrostatic repulsive force between oxygen atoms to lead Li 2 C 2 O 4 The crystal structure of (C) becomes loose and intermolecular forces become weaker, so Li 2 (C 2 O 4 ) a (SO 4 ) b (NO 3 ) c The polarization voltage required by decomposition is reduced, and the lithium supplementing material has lower decomposition potential; in addition to NO 3 - And/or SO 4 2- The doping of the lithium supplementing material can also improve the conductivity of the lithium supplementing material and promote the decomposition of the lithium supplementing material.
In some embodiments of the present application, the lithium-supplementing material has an average particle size of 1nm to 20 μm. The average particle size of the lithium supplementing material may be, but is not limited to, specifically 1nm, 10nm, 50nm, 0.1 μm, 0.3 μm, 0.5 μm, 0.8 μm, 1 μm, 2 μm, 3 μm, 5 μm. In some embodiments, the lithium-compensating material has an average particle size of 0.1 μm to 5 μm. The average particle size of the lithium supplementing material can be measured by a particle size distribution instrument, and the D50 particle size of the lithium supplementing material is obtained by testing, namely the average particle size of the lithium supplementing material, wherein the D50 particle size refers to the particle size corresponding to the cumulative particle size distribution percentage of the lithium supplementing material reaching 50%. In some embodiments, the particle size of the lithium-compensating material is 0.3 μm to 1 μm. The particle size of the lithium supplementing material is controlled to be favorable for fully contacting the lithium supplementing material with the positive electrode material, so that uniform lithium supplementing is realized, and in addition, the lithium supplementing material can be fully contacted with the conductive agent, so that the decomposition rate of the lithium supplementing material is accelerated, the lithium supplementing material is ensured to be decomposed under a lower potential, the lithium supplementing material is fully decomposed before the charging cut-off voltage, and active lithium is fully released to exert the maximum lithium supplementing. In addition, the lithium supplementing material with the particle size distribution is easy to prepare, has good particle dispersibility, has good stability in air, and is not easy to absorb water and deteriorate, so that effective lithium supplementing of the battery is realized.
In some embodiments of the present application, a compound Li 2 (C 2 O 4 ) a (SO 4 ) b (NO 3 ) c Wherein a has a value of 0.9 or more and less than 1, and b+0.5c has a value of 0.1 or less, i.e., a ratio of a to b+0.5c is 9 or more. The value of a can be, but is not limited to, specifically 0.9, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99 or 0.999. The value of b+0.5c may be, but is not limited to, 0.1, 0.09, 0.08, 0.07, 0.06, 0.05, 0.04, 0.03, 0.02, 0.01 or 0.001. The ratio of a to b+0.5c may be, but is not limited to, in particular 9, 9.5, 10, 10.5, 11, 13, 15, 18, 20, 22, 25, 30, 35 or 40. The control of the value of a or b+0.5c is to control the doping ion NO 3 - And/or SO 4 2- When the doping amount of the doping ions is 0, the material is lithium oxalate, the theoretical mass specific capacity of the lithium oxalate is 526mAh/g, but the decomposition lithium removal potential of the lithium oxalate is high, and the compatibility with the charge cut-off voltage of a conventional battery is poor. The application found that a small amount of NO was added to lithium oxalate 3 - And/or SO 4 2- The decomposition potential of lithium oxalate can be reduced, along with the increase of the content of doped ions, the decomposition potential of the material can be continuously reduced, when the value of a is more than or equal to 0.9 and less than 1, the effect of expanding the lattice spacing of lithium oxalate by doped ions is enough to ensure that the lithium supplementing material has lower decomposition potential, the battery is charged at a lower potential for the first time and has no influence on the positive electrode active substance, electrolyte and other battery components basically, so that the battery has good stability, and when the value of b+0.5c is less than or equal to 0.1, the content of doped ions is lower, the influence of doped ions on the positive electrode material can be reduced, and the positive electrode material can be orderly deintercalated.
In the application, the lithium supplementing material can decompose to generate active lithium under the decomposition potential so as to realize lithium supplementing. Specifically, during the first charge of the secondary battery, li 2 (C 2 O 4 ) a (SO 4 ) b (NO 3 ) c Self-decomposition can be realized in a charge-discharge set interval, and the decomposition product is active lithium Li + And carbon dioxide gas CO 2 NO and small amounts of NO 3 - And-Or SO 4 2- . Active lithium Li + Active lithium consumed by solid electrolyte film (SEI) formed on the surface of the negative electrode can be supplemented, so that the battery capacity is improved, and gas generated in the decomposition process can be safely discharged during initial charge, so that the performance of the battery is not affected.
The lithium supplementing material can be divided into a first lithium supplementing material, a second lithium supplementing material and a third lithium supplementing material according to the type of the doping ions, wherein the first lithium supplementing material comprises a compound with a chemical formula of Li 2 (C 2 O 4 ) a (SO 4 ) b Of (2), i.e. Li 2 (C 2 O 4 ) a (SO 4 ) b (NO 3 ) c In the compound, 0 < a < 1, b > 0, c=0, and a+b=1; the second lithium supplementing material comprises a compound with a chemical formula of Li 2 (C 2 O 4 ) a (NO 3 ) c Of (2), i.e. Li 2 (C 2 O 4 ) a (SO 4 ) b (NO 3 ) c In the compound, 0 < a < 1, b=0, c > 0, a+0.5c=1; the third lithium supplementing material comprises a compound with a chemical formula of Li 2 (C 2 O 4 ) a (SO 4 ) b (NO 3 ) c 0 < a < 1, b > 0, c > 0, a+b+0.5c=1.
For the first lithium supplementing material, the compound Li 2 (C 2 O 4 ) a (SO 4 ) b Anion C in (B) 2 O 4 2- And SO 4 2- The valence states of (2) are-2, and C 2 O 4 2- And SO 4 2- SO that the relative molecular masses of (2) are similar 4 2- Has little influence on the lithium supplementing capacity, i.e. Li 2 (C 2 O 4 ) a (SO 4 ) b The lithium-supplementing capacity is similar to that of lithium oxalate; lithium sulfate and lithium oxalate belong to monoclinic system, SO 4 2- O and C containing lone pair electrons 2 O 4 2- With electrostatic forces between C polarized by oxygen atoms, SO that SO 4 2- In Li 2 C 2 O 4 Is inserted between the layers of the sheet-like structure,SO 4 2- the radius of S atom is larger, and the SO of tetrahedral structure 4 2- Has a certain radial length, thereby expanding Li 2 C 2 O 4 To make Li 2 C 2 O 4 The crystal structure of the lithium ion battery is loosened, the intermolecular acting force is weakened, the polarization voltage required by the decomposition of the lithium ion battery material is reduced, and the material decomposition potential is further reduced; in addition to that, SO 4 2- The valence state of the S element is the highest valence state which can be achieved by the S element, and the S element is difficult to continuously decompose under high voltage, so that the residual components of the lithium supplementing material after battery formation are mainly lithium sulfate, and the lithium sulfate is not decomposed in the subsequent battery cycle, thereby being beneficial to improving the safety of the battery.
In some embodiments of the present application, a compound Li 2 (C 2 O 4 ) a (SO 4 ) b Wherein, the value of a is more than or equal to 0.9 and less than 1, and the value of b is less than or equal to 0.1, namely the ratio of a to b is more than or equal to 9. The value of control a or b is control SO 4 2- Is added to the substrate. In the present application, a small amount of SO is doped in lithium oxalate 4 2- The decomposition potential of lithium oxalate can be reduced, and along with SO 4 2- The decomposition potential of the material is also continuously reduced when the content is increased, and when the value of x is more than or equal to 0.9 and less than 1, the doped ions SO 4 2- The effect of expanding the interlayer spacing of the lithium oxalate lattice is enough to ensure that the lithium supplementing material has lower decomposition potential, and charging is basically not influenced on anode active substances, electrolyte and other battery components when the lithium supplementing material is charged at lower potential, SO that the battery has good stability, and when the value of b is less than or equal to 0.1, SO is ensured 4 2- The content of the lithium ion doped anode material is low, the influence of doped ions on the anode material can be reduced, and the anode material can be ensured to orderly deintercalate lithium.
For the second lithium supplementing material, the compound Li 2 (C 2 O 4 ) a (NO 3 ) c Anionic NO in (3) 3 - Relative molecular mass of C 2 O 4 2- Lower, so NO 3 - The doping of the lithium-supplementing material can reduce the relative molecular mass of the whole lithium-supplementing material and improve the lithium-supplementing gram capacity of the lithium-supplementing material; NO (NO) 3 - O and C containing lone pair electrons 2 O 4 2- With electrostatic forces between C polarized by oxygen atoms such that NO 3 - In Li 2 C 2 O 4 NO of sheet structure 3 - Li intercalation 2 C 2 O 4 Can enlarge Li in the crystal lattice 2 C 2 O 4 To make Li 2 C 2 O 4 The crystal structure of (a) becomes loose, the intermolecular force becomes weak, the polarization voltage required for decomposing the lithium supplementing material becomes small, the material decomposition potential is reduced, and NO 3 - Wherein N has a radius less than C 2 O 4 2- The radius of C in the reactor is more beneficial to NO 3 - The intercalation of lithium oxalate in the radial direction is improved; in addition to NO 3 - The valence state of the element N is the highest valence state which can be achieved by the element N, and the element N is difficult to continuously decompose under high voltage, so that the residual components of the lithium supplementing material after battery formation are mainly lithium nitrate, and the lithium nitrate is not decomposed in the subsequent battery cycle, thereby being beneficial to improving the safety of the battery.
In some embodiments of the present application, a compound Li 2 (C 2 O 4 ) a (NO 3 ) c Wherein, the value of a is more than or equal to 0.9 and less than 1, and the value of c is less than or equal to 0.2, namely the ratio of a to c is more than or equal to 4.5. The value of control a or c is control NO 3 - The research of the application shows that a small amount of NO is doped in the lithium oxalate 3 - The decomposition potential of lithium oxalate can be reduced, and the lithium oxalate can be decomposed along with NO 3 - The decomposition potential of the material is also continuously reduced when the content is increased, and when the value of x is more than or equal to 0.9 and less than 1, the ion NO is doped 3 - The effect of expanding the interlayer spacing of the lithium oxalate lattice is enough to ensure that the lithium supplementing material has lower decomposition potential, and charging is basically not influenced on anode active substances, electrolyte and other battery components when being charged at lower potential, thereby ensuring electricity The pool has good stability, and when the value of c is less than or equal to 0.2, NO 3 - The content of the lithium ion doped anode material is low, the influence of doped ions on the anode material can be reduced, and the anode material can be ensured to orderly deintercalate lithium.
In the application, the second lithium supplementing material has better lithium supplementing performance than the first lithium supplementing material, and specifically, the compound Li 2 (C 2 O 4 ) a (NO 3 ) c The ionic valence state of the nitrate radical is-1, relative to the compound Li 2 (C 2 O 4 ) a (SO 4 ) b The sulfate ion with medium-2 valence has smaller binding of nitrate to lithium ion, so that the lithium ion is easier to be extracted, and the lithium ion is more easily extracted from the lithium ion-ion complex Li 2 (C 2 O 4 ) a (SO 4 ) b And the compound Li 2 (C 2 O 4 ) a (NO 3 ) c When the values of a in the two compounds are the same, the number of nitrate ions is twice that of sulfate ions, and more nitrate ions are more beneficial to reducing the decomposition potential of lithium oxalate, so that the damage of high voltage to active materials is reduced, and the stability of the battery is improved.
For the third lithium supplementing material, the compound Li 2 (C 2 O 4 ) a (SO 4 ) b (NO 3 ) c Contains doped ion NO 3 - And SO 4 2- ，NO 3 - And SO 4 2- Can be matched with each other to ensure that the lithium supplementing material has low decomposition potential and good conductivity. In particular, tetrahedrally structured SOs 4 2- The radial dimension is larger, the interlayer acting force of lithium oxalate can be greatly reduced in the layered structure of the lithium oxalate, but the radial conductivity of the lithium supplementing material can be reduced to a certain extent, and the NO with a sheet structure 3 - Can be filled between lithium oxalate layers, is favorable for improving the radial conductivity of lithium oxalate, thereby accelerating the decomposition rate of the lithium supplementing material, ensuring that the lithium supplementing material can be decomposed under lower potential, ensuring that the lithium supplementing material is fully decomposed before the charging cut-off voltage and is fully releasedActive lithium is produced to exert the greatest lithium supplementation.
In some embodiments of the present application, a compound Li 2 (C 2 O 4 ) a (SO 4 ) b (NO 3 ) c Wherein a has a value of 0.9 or more and less than 1, and b+0.5c has a value of 0.1 or less, i.e., a ratio of 0.9 or more to b+0.5c. In some embodiments of the present application, 0 < b < c, that is, the doping amount of nitrate ions is greater than the doping amount of sulfate ions, and in some examples, the ratio of the doping amount of nitrate ions to the doping amount of sulfate ions is 1-10, that is, 1 < c/b < 10, and the value of c/b may be, but not limited to, 1, 3, 5, 7, 9 or 10. The control of the relative molar ratio of nitrate ions and sulfate ions is beneficial to coordinating the performances of the nitrate ions and the sulfate ions, so that the compound has low decomposition potential and good conductivity at the same time, and active lithium is released to the greatest extent to realize lithium supplementation.
In the embodiment of the application, the decomposition potential of the lithium supplementing material is smaller than or equal to 4.6V, the decomposition potential can be well compatible with the charge cut-off voltage of a conventional battery, the positive electrode active substance, the electrolyte and other battery components cannot be influenced, and meanwhile, the lithium supplementing material can be guaranteed to fully decompose and release active lithium to compensate the active lithium consumed by the solid electrolyte film (SEI) formed by the negative electrode, so that a good lithium supplementing effect is achieved. In some embodiments of the present application, the decomposition potential of the lithium-supplementing material is greater than or equal to 4.4V and less than or equal to 4.6V, where the decomposition potential is applicable to most of the positive electrode materials, such as lithium iron phosphate (charge cutoff voltage 3.8V), lithium nickel cobalt manganese oxide (NCM, charge cutoff voltage 4.35V), and the use of the lithium-supplementing material can avoid irreversible structural changes of the positive electrode material under the condition of long-time high charge voltage on the premise of ensuring sufficient lithium supplementation, thereby improving stability and cycle performance of the battery.
The lithium supplementing material provided by the application has lower decomposition potential and higher lithium supplementing capacity. Li (Li) 2 (C 2 O 4 ) a (SO 4 ) b (NO 3 ) c The introduction of the medium doping ions leads the interlayer spacing of the crystal layer of the lithium oxalate to be enlarged and the crystal structure to be looseThe intermolecular forces are weakened, the polarization voltage required for decomposing the lithium-supplementing material becomes small, and the decomposition potential of the material is lowered. The lithium supplementing material is added into the battery, so that decomposition and lithium removal under the condition of low voltage can be realized, lithium supplementation of the battery is realized, irreversible structural change of the positive electrode material under the condition of continuous high charging voltage is avoided, and the stability and the cycle performance of the battery are improved. In addition, the decomposition voltage of the lithium supplementing material can be matched with the highest charge cut-off voltage bearable by a battery system by adjusting the content of doped ions and the particle size of the material so as to obtain larger lithium supplementing capacity on the premise of not influencing the battery system.
The lithium supplementing material can be prepared by different methods, and the specific preparation method is not limited. In some embodiments, a method of preparing a lithium-supplementing material includes: dissolving oxalic acid and sulfuric acid in water, adding lithium hydroxide into the solution to obtain mixed solution of lithium oxalate and lithium sulfate, evaporating and crystallizing the mixed solution at 40-100 ℃ to obtain Li 2 (C 2 O 4 ) a (SO 4 ) b ·zH 2 O, li is then 2 (C 2 O 4 ) a (SO 4 ) b ·zH 2 O is dried in vacuum at 100 ℃ to 200 ℃ to obtain Li 2 (C 2 O 4 ) a (SO 4 ) b . In some embodiments, a method of preparing a lithium-supplementing material includes: dissolving oxalic acid and nitric acid in water, adding lithium hydroxide into the solution to obtain a mixed solution of lithium oxalate and lithium nitrate, and evaporating and crystallizing the mixed solution at 40-100 ℃ to obtain Li 2 (C 2 O 4 ) a (NO 3 ) c ·zH 2 O, li is then 2 (C 2 O 4 ) a (NO 3 ) c ·zH 2 O is dried in vacuum at 100 ℃ to 200 ℃ to obtain Li 2 (C 2 O 4 ) a (NO 3 ) c . In some embodiments, a method of preparing a lithium-supplementing material includes: dissolving oxalic acid, nitric acid and sulfuric acid in water, and adding lithium hydroxide into the solution to obtain a mixed solution of lithium oxalate, lithium sulfate and lithium nitrateEvaporating and crystallizing the mixed solution at 40-100 ℃ to obtain Li 2 (C 2 O 4 ) a (SO 4 ) b (NO 3 ) c ·zH 2 O, li is then 2 (C 2 O 4 ) a (SO 4 ) b (NO 3 ) c ·zH 2 O is dried in vacuum at 100 ℃ to 200 ℃ to obtain Li 2 (C 2 O 4 ) a (SO 4 ) b (NO 3 ) c . It should be noted that, because of the low solubility of lithium oxalate (5.85%), when oxalic acid is added to water, the concentration of oxalic acid in the solution is low to ensure that lithium oxalate does not precipitate.
The preparation method of the lithium supplementing material is simple, raw materials are easy to obtain, the production cost is low, mass production can be easily carried out, and the lithium supplementing material can be widely applied to industrial production.
The application also provides a positive electrode plate, which comprises an active material and the lithium supplementing material.
In some embodiments of the present application, the active material includes one or more of lithium iron phosphate, lithium cobalt oxide, lithium manganate, ternary materials, lithium manganese phosphate, lithium manganese iron phosphate, lithium vanadium phosphate, lithium vanadyl phosphate, lithium vanadate, and lithium-rich manganese-based materials. The lithium supplementing material has low decomposition potential, and can supplement lithium in a lower voltage interval, so that the lithium supplementing material can be compatible with most of positive electrode materials, inhibit structural change of the positive electrode materials under high voltage and prolong the cycle performance of the battery.
In some embodiments of the present application, the mass ratio of the lithium supplementing material to the active material is 1 (5-1000), i.e., the addition amount of the lithium supplementing material to the active material is 0.1% -20%. The mass ratio of the lithium-supplementing material to the active material may specifically be, but is not limited to, 1:5, 1:10, 1:15, 1:20, 1:50, 1:80, 1:100, 1:200, 1:400, 1:600, 1:800, or 1:1000. In some embodiments of the present application, the mass ratio of the lithium supplementing material to the active material is 1 (10-100), i.e., the adding amount of the lithium supplementing material to the active material is 1% -10%. In some embodiments of the present application, the mass ratio of the lithium supplementing material to the active material is 1 (20-50), i.e., the addition amount of the lithium supplementing material to the active material is 2% -5%. The control of the addition amount of the lithium supplementing material can ensure that the lithium supplementing material fully supplements lithium for the battery, improves the initial efficiency of the battery, is beneficial to controlling the time of the formation process and reduces the occurrence of side reactions.
In some embodiments of the present application, the positive electrode tab includes a current collector and an active material layer disposed on the current collector, the active material layer including an active material and a lithium supplementing material. In some embodiments of the present application, the active material layer further includes a conductive agent and a binder, wherein the conductive agent may be one or more of acetylene black, carbon nanotubes, carbon nanofibers, activated carbon, and graphene, and the binder may be one or more of polyvinylidene fluoride, polytetrafluoroethylene, polyhexafluoropropylene, styrene-butadiene rubber, sodium carboxymethyl cellulose, polyvinylpyrrolidone, polyvinyl ether, polymethyl methacrylate, polyamide, polyacrylonitrile, and polyacrylate.
In some embodiments of the present application, the active material is present in the active material layer in an amount of 80% to 99% by mass. The mass percentage of the active material in the active material layer may be, but is not limited to, 80%, 85%, 89%, 90%, 93%, 95%, 98%, or 99% in particular. In some embodiments of the present application, the mass percentage of the lithium supplementing material in the active material layer is 0.1% -15%. The mass percentage of the lithium supplementing material in the active material layer may be, but not limited to, 0.1%, 1%, 3%, 5%, 10% or 15%. In some embodiments of the present application, the mass percentage of the binder in the active material layer is 0.1% to 15%. In some embodiments of the present application, the conductive agent is present in the active material layer in an amount of 0.1% to 20% by mass.
The application also provides a preparation method of the positive electrode plate, and in some embodiments, the preparation method of the positive electrode plate comprises a direct mixing method, wherein the direct mixing method comprises the following steps: mixing a lithium supplementing material, a positive electrode material, a conductive agent, a binder and a solvent to form positive electrode slurry, coating the positive electrode slurry on the surface of a current collector, and drying to obtain the positive electrode plate.
In some embodiments of the present application, the positive electrode sheet includes a current collector, a positive electrode material layer and a lithium supplementing layer that set gradually, the positive electrode material layer includes an active material, and the lithium supplementing layer includes a lithium supplementing material. In some embodiments of the present application, the positive electrode material layer includes an active material, a conductive agent, and a binder, and the lithium supplementing layer includes a lithium supplementing material, a conductive agent, and a binder. In some embodiments, the method of preparing the positive electrode sheet includes a coating method comprising: mixing a positive electrode material, a conductive agent, a binder and a solvent to form positive electrode slurry, coating the positive electrode slurry on the surface of a current collector to form a positive electrode material layer, coating a lithium supplementing material, the conductive agent and the binder on the surface of the positive electrode material layer, and forming a lithium supplementing layer on the surface of the positive electrode material layer to obtain the positive electrode plate.
The application also provides a secondary battery comprising a positive electrode, a negative electrode, a diaphragm and electrolyte, wherein the positive electrode comprises a positive electrode plate. Referring to fig. 1, fig. 1 is a schematic structural diagram of a secondary battery according to an embodiment of the present application. The secondary battery includes a positive electrode 10, a negative electrode 20, a separator 30, and an electrolyte 40. When the secondary battery is charged, lithium ions are separated from the positive electrode 10 and deposited to the negative electrode 20 after passing through the electrolyte 40; during discharge, lithium ions are extracted from the negative electrode 20, and then inserted into the positive electrode 10 through the electrolyte 40. The secondary battery provided by the application has higher capacity and cycle performance due to the adoption of the positive electrode plate. In some embodiments of the present application, the secondary battery comprises a lithium secondary battery.
In some embodiments of the present application, the negative electrode of the secondary battery includes one or more of a carbon-based negative electrode and a lithium negative electrode. Wherein the carbon-based negative electrode may include one or more of graphite, hard carbon, soft carbon, and graphene; the lithium negative electrode may include metallic lithium or a lithium alloy, and the lithium alloy may be specifically at least one of a lithium silicon alloy, a lithium sodium alloy, a lithium potassium alloy, a lithium aluminum alloy, a lithium tin alloy, and a lithium indium alloy. In some embodiments of the present application, the current collector of the negative electrode comprises copper foil, and the negative electrode active material comprises one or more of natural graphite, artificial graphite, hard carbon, and soft carbon; the binder comprises one or more of polyacrylic acid (PAA), polyvinylidene fluoride (PVDF), carboxymethyl cellulose (CMC), and styrene-butadiene latex (SBR); the conductive agent comprises one or more of acetylene black, ketjen black, super-P, carbon nanotubes, carbon nanofibers, activated carbon and graphene. In the present application, the preparation method of the negative electrode may employ any method known in the art.
In this application, the separator of the secondary battery may be any separator known to those skilled in the art, for example, the separator may be one or more of a polyolefin microporous film, polyethylene terephthalate, polyethylene felt, glass fiber felt, or ultra fine glass fiber paper.
In the present application, the electrolyte of the secondary battery includes a solution of an electrolyte lithium salt in a nonaqueous solvent. In an embodiment of the present application, the electrolyte lithium salt includes lithium hexafluorophosphate (LiPF 6 ) Lithium perchlorate (LiClO) 4 ) Lithium tetrafluoroborate (LiBF) 4 ) Lithium hexafluoroarsenate (LiAsF) 6 ) Lithium hexafluorosilicate (Li) 2 SiF 6 ) Lithium tetraphenyl borate (LiB (C) 6 H5) 4 ) Lithium chloride (LiCl), lithium bromide (LiBr), lithium chloroaluminate (LiAlCl) 4 ) Lithium fluorocarbon sulfonate (LiC (SO) 2 CF 3 ) 3 )、LiCH 3 SO 3 、LiN(SO 2 CF 3 ) 2 And LiN (SO) 2 C 2 F 5 ) 2 One or more of the following. In some embodiments of the present application, the nonaqueous solvent includes one or more of a chain acid ester and a cyclic acid ester. In some embodiments of the present application, the chain acid ester includes one or more of dimethyl carbonate (DMC), diethyl carbonate (DEC), ethylmethyl carbonate (EMC), methylpropyl carbonate (MPC), and dipropyl carbonate (DPC). In some embodiments of the present application, the chain acid esters include fluorine-, sulfur-, or unsaturated bond-containing chain organic esters. In some embodiments of the present application, the cyclic acid ester includes one or more of Ethylene Carbonate (EC), propylene Carbonate (PC), vinylene Carbonate (VC), gamma-butyrolactone (gamma-BL), and sultone. In some embodiments of the present application, the cyclic acid esters include fluorine-, sulfur-or unsaturated bond-containing cyclic organic esters. In some embodiments of the present application, the nonaqueous solvent includes one or more of a chain ether and a cyclic ether solution. In some embodiments of the present application, the cyclic ethers include Tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-MeTHF), 1, 3-Dioxolane (DOL), and 4-methyl-1, 3-dioctane One or more of the oxolane (4-MeDOL). In some embodiments of the present application, the cyclic ether includes a fluorine-, sulfur-or unsaturated bond-containing cyclic organic ether. In some embodiments of the present application, the chain ether includes one or more of Dimethoxymethane (DMM), 1, 2-Dimethoxyethane (DME), 1, 2-Dimethoxypropane (DMP), and Diglyme (DG). In some embodiments of the present application, the chain ether includes a fluorine-, sulfur-or unsaturated bond-containing chain organic ether. In the embodiment of the application, the concentration of the electrolyte lithium salt in the electrolyte is 0.1mol/L to 15mol/L. In some embodiments of the present application, the concentration of the lithium salt of the electrolyte is 1mol/L to 10mol/L.
In the embodiment of the application, the battery can be prepared by adopting any one of lamination process or winding process. In some embodiments of the present application, the battery is fabricated using a lamination process.
The application also provides electronic equipment, and the electronic equipment comprises the secondary battery provided by the application, and the secondary battery supplies power for the electronic equipment.
The technical scheme of the application is further described in the following several embodiments.
Example 1
A preparation method of the lithium supplementing material comprises the following steps:
mixing oxalic acid and sulfuric acid according to a molar ratio of 9:1 to obtain a mixed solution, adding lithium hydroxide into the mixed solution to obtain a mixed solution of lithium oxalate and lithium sulfate, and evaporating and crystallizing the mixed solution at 60 ℃ to obtain Li 2 (C 2 O 4 ) 0.9 (SO 4 ) 0.1 ·zH 2 O, li is 2 (C 2 O 4 ) 0.9 (SO 4 ) 0.1 ·zH 2 O is dried in vacuum at 150 ℃ to obtain anhydrous Li 2 (C 2 O 4 ) 0.9 (SO 4 ) 0.1 For Li 2 (C 2 O 4 ) 0.9 (SO 4 ) 0.1 Grinding is carried out to obtain the lithium supplementing material with the average particle diameter of 0.3 mu m.
In order to test the decomposition voltage of the obtained lithium supplementing material, a test battery is prepared by taking the lithium supplementing material as a battery anode material, and the preparation method of the test battery is as follows:
acetylene black is used as a conductive agent, polyvinylidene fluoride (PVDF) is used as a binder, N-methylpyrrolidone (NMP) is used as a dispersing agent, the materials for supplementing lithium are uniformly mixed according to the mass ratio of acetylene black to PVDF to NMP=85:10:5:50 to obtain positive electrode slurry, aluminum foil is used as a current collector for coating, and then the positive electrode slurry is placed in a 120 ℃ oven for vacuum drying for 24 hours, and then pressed into tablets and rolled and cut to obtain the positive electrode plate. 1mol/L LiPF (lithium ion battery) with lithium metal sheet as negative electrode and cellgard 2400 polypropylene porous membrane as diaphragm 6 The mixed solution (volume ratio=1:1) of Ethylene Carbonate (EC) and dimethyl carbonate (DMC) is an electrolyte; the assembly of the test cell was completed in an argon-filled glove box to give test cell sample C1.
Example 2
A preparation method of the lithium supplementing material comprises the following steps:
mixing oxalic acid and sulfuric acid according to a molar ratio of 92:8 to obtain a mixed solution, adding lithium hydroxide into the mixed solution to obtain a mixed solution of lithium oxalate and lithium sulfate, and evaporating and crystallizing the mixed solution at 60 ℃ to obtain Li 2 (C 2 O 4 ) 0.92 (SO 4 ) 0.08 ·zH 2 O, li is 2 (C 2 O 4 ) 0.92 (SO 4 ) 0.08 ·zH 2 O is dried in vacuum at 150 ℃ to obtain anhydrous Li 2 (C 2 O 4 ) 0.92 (SO 4 ) 0.08 For Li 2 (C 2 O 4 ) 0.92 (SO 4 ) 0.08 Grinding is carried out to obtain the lithium supplementing material with the average particle diameter of 0.3 mu m.
To test the decomposition voltage of the obtained lithium-compensating material, a test battery was prepared using the lithium-compensating material as a battery positive electrode material, and a test battery sample C2 was obtained in the same manner as in example 1.
Example 3
A preparation method of the lithium supplementing material comprises the following steps:
mixing oxalic acid and sulfuric acid according to a molar ratio of 96:4 to obtain a mixed solution, and adding lithium hydroxide into the mixed solution to obtain lithium oxalate and lithium sulfateEvaporating and crystallizing the mixed solution at 60 ℃ to obtain Li 2 (C 2 O 4 ) 0.96 (SO 4 ) 0.04 ·zH 2 O, li is 2 (C 2 O 4 ) 0.96 (SO 4 ) 0.04 ·zH 2 O is dried in vacuum at 150 ℃ to obtain anhydrous Li 2 (C 2 O 4 ) 0.96 (SO 4 ) 0.04 For Li 2 (C 2 O 4 ) 0.96 (SO 4 ) 0.04 Grinding is carried out to obtain the lithium supplementing material with the average particle diameter of 0.3 mu m.
To test the decomposition voltage of the obtained lithium-compensating material, a test battery was prepared using the lithium-compensating material as a battery positive electrode material, and a test battery sample C3 was obtained in the same manner as in example 1.
Example 4
A preparation method of the lithium supplementing material comprises the following steps:
mixing oxalic acid and sulfuric acid according to a molar ratio of 4:1 to obtain a mixed solution, adding lithium hydroxide into the mixed solution to obtain a mixed solution of lithium oxalate and lithium sulfate, and evaporating and crystallizing the mixed solution at 60 ℃ to obtain Li 2 (C 2 O 4 ) 0.8 (SO 4 ) 0.2 ·zH 2 O, li is 2 (C 2 O 4 ) 0.8 (SO 4 ) 0.2 ·zH 2 O is dried in vacuum at 150 ℃ to obtain anhydrous Li 2 (C 2 O 4 ) 0.8 (SO 4 ) 0.2 For Li 2 (C 2 O 4 ) 0.8 (SO 4 ) 0.2 Grinding is carried out to obtain the lithium supplementing material with the average particle diameter of 0.3 mu m.
To test the decomposition voltage of the obtained lithium-compensating material, a test battery was prepared using the lithium-compensating material as a battery positive electrode material, and a test battery sample C4 was obtained in the same manner as in example 1.
Example 5
The composition of the lithium-supplementing material in example 5 was the same as in example 1, except that the average particle size of the lithium-supplementing material in example 5 was 500. Mu.m. Test cell C5 was prepared in the same manner as in example 1.
Example 6
A preparation method of the lithium supplementing material comprises the following steps:
mixing oxalic acid and nitric acid according to a molar ratio of 9:2 to obtain a mixed solution, adding lithium hydroxide into the mixed solution to obtain a mixed solution of lithium oxalate and lithium nitrate, and evaporating and crystallizing the mixed solution at 60 ℃ to obtain Li 2 (C 2 O 4 ) 0.9 (NO 3 ) 0.2 ·zH 2 O, li is 2 (C 2 O 4 ) 0.9 (NO 3 ) 0.2 ·zH 2 O is dried in vacuum at 150 ℃ to obtain anhydrous Li 2 (C 2 O 4 ) 0.9 (NO 3 ) 0.2 For Li 2 (C 2 O 4 ) 0.9 (NO 3 ) 0.2 Grinding is carried out to obtain the lithium supplementing material with the average particle diameter of 0.3 mu m.
To test the decomposition voltage of the obtained lithium-compensating material, a test battery was prepared using the lithium-compensating material as a battery positive electrode material, and a test battery sample C6 was obtained in the same manner as in example 1.
Example 7
A preparation method of the lithium supplementing material comprises the following steps:
mixing oxalic acid and nitric acid according to a molar ratio to obtain a mixed solution, adding lithium hydroxide into the mixed solution to obtain a mixed solution of lithium oxalate and lithium nitrate, and evaporating and crystallizing the mixed solution at 60 ℃ to obtain Li 2 (C 2 O 4 ) 0.92 (NO 3 ) 0.16 ·zH 2 O, li is 2 (C 2 O 4 ) 0.92 (NO 3 ) 0.16 ·zH 2 O is dried in vacuum at 150 ℃ to obtain anhydrous Li 2 (C 2 O 4 ) 0.92 (NO 3 ) 0.16 For Li 2 (C 2 O 4 ) 0.92 (NO 3 ) 0.16 Grinding is carried out to obtain the lithium supplementing material with the average particle diameter of 0.3 mu m.
To test the decomposition voltage of the obtained lithium-compensating material, a test battery was prepared using the lithium-compensating material as a battery positive electrode material, and a test battery sample C7 was obtained in the same manner as in example 1.
Example 8
A preparation method of the lithium supplementing material comprises the following steps:
mixing oxalic acid and nitric acid according to a molar ratio to obtain a mixed solution, adding lithium hydroxide into the mixed solution to obtain a mixed solution of lithium oxalate and lithium nitrate, and evaporating and crystallizing the mixed solution at 60 ℃ to obtain Li 2 (C 2 O 4 ) 0.96 (NO 3 ) 0.08 ·zH 2 O, li is 2 (C 2 O 4 ) 0.96 (NO 3 ) 0.08 ·zH 2 O is dried in vacuum at 150 ℃ to obtain anhydrous Li 2 (C 2 O 4 ) 0.96 (NO 3 ) 0.08 For Li 2 (C 2 O 4 ) 0.96 (NO 3 ) 0.08 Grinding is carried out to obtain the lithium supplementing material with the average particle diameter of 0.3 mu m.
To test the decomposition voltage of the obtained lithium-compensating material, a test battery was prepared using the lithium-compensating material as a battery positive electrode material, and a test battery sample C8 was obtained in the same manner as in example 1.
Example 9
A preparation method of the lithium supplementing material comprises the following steps:
mixing oxalic acid and nitric acid according to a molar ratio to obtain a mixed solution, adding lithium hydroxide into the mixed solution to obtain a mixed solution of lithium oxalate and lithium nitrate, and evaporating and crystallizing the mixed solution at 60 ℃ to obtain Li 2 (C 2 O 4 ) 0.8 (NO 3 ) 0.4 ·zH 2 O, li is 2 (C 2 O 4 ) 0.8 (NO 3 ) 0.4 ·zH 2 O is dried in vacuum at 150 ℃ to obtain anhydrous Li 2 (C 2 O 4 ) 0.8 (NO 3 ) 0.4 For Li 2 (C 2 O 4 ) 0.8 (NO 3 ) 0.4 Grinding is carried out to obtain the lithium supplementing material with the average particle diameter of 0.3 mu m.
To test the decomposition voltage of the obtained lithium-compensating material, a test battery was prepared using the lithium-compensating material as a battery positive electrode material, and a test battery sample C9 was obtained in the same manner as in example 1.
Example 10
The lithium-supplementing material in example 10 had the same composition as in example 1, and was Li 2 (C 2 O 4 ) 0.9 (NO 3 ) 0.2 The difference is that the lithium supplementing material of example 10 has an average particle size of 500 μm. Test cell C10 was prepared in the same manner as in example 1.
Example 11
A preparation method of the lithium supplementing material comprises the following steps:
mixing oxalic acid, nitric acid and sulfuric acid according to a mole ratio to obtain a mixed solution, adding lithium hydroxide into the mixed solution to obtain a mixed solution of lithium oxalate, lithium sulfate and lithium nitrate, and evaporating and crystallizing the mixed solution at 60 ℃ to obtain Li 2 (C 2 O 4 ) 0.9 (SO 4 ) 0.06 (NO 3 ) 0.08 ·zH 2 O, li is 2 (C 2 O 4 ) 0.9 (SO 4 ) 0.06 (NO 3 ) 0.08 ·zH 2 O is dried in vacuum at 150 ℃ to obtain anhydrous Li 2 (C 2 O 4 ) 0.9 (SO 4 ) 0.06 (NO 3 ) 0.08 For Li 2 (C 2 O 4 ) 0.9 (SO 4 ) 0.06 (NO 3 ) 0.08 Grinding is carried out to obtain the lithium supplementing material with the average particle diameter of 0.3 mu m.
To test the decomposition voltage of the obtained lithium-compensating material, a test battery was prepared using the lithium-compensating material as a battery positive electrode material, and a test battery sample C11 was obtained in the same manner as in example 1.
Example 12
A preparation method of the lithium supplementing material comprises the following steps:
mixing oxalic acid, nitric acid and sulfuric acid according to a mole ratio to obtain a mixed solution, and adding lithium hydroxide into the mixed solution to obtain lithium oxalate,The mixed solution of lithium sulfate and lithium nitrate is evaporated and crystallized at 60 ℃ to obtain Li 2 (C 2 O 4 ) 0.9 (SO 4 ) 0.09 (NO 3 ) 0.02 ·zH 2 O, li is 2 (C 2 O 4 ) 0.9 (SO 4 ) 0.09 (NO 3 ) 0.02 ·zH 2 O is dried in vacuum at 150 ℃ to obtain anhydrous Li 2 (C 2 O 4 ) 0.9 (SO 4 ) 0.09 (NO 3 ) 0.02 For Li 2 (C 2 O 4 ) 0.9 (SO 4 ) 0.09 (NO 3 ) 0.02 Grinding is carried out to obtain the lithium supplementing material with the average particle diameter of 0.3 mu m.
To test the decomposition voltage of the obtained lithium-compensating material, a test battery was prepared using the lithium-compensating material as a battery positive electrode material, and a test battery sample C12 was obtained in the same manner as in example 1.
Example 13
A preparation method of the lithium supplementing material comprises the following steps:
mixing oxalic acid, nitric acid and sulfuric acid according to a mole ratio to obtain a mixed solution, adding lithium hydroxide into the mixed solution to obtain a mixed solution of lithium oxalate, lithium sulfate and lithium nitrate, and evaporating and crystallizing the mixed solution at 60 ℃ to obtain Li 2 (C 2 O 4 ) 0.9 (SO 4 ) 0.01 (NO 3 ) 0.18 ·zH 2 O, li is 2 (C 2 O 4 ) 0.9 (SO 4 ) 0.01 (NO 3 ) 0.18 ·zH 2 O is dried in vacuum at 150 ℃ to obtain anhydrous Li 2 (C 2 O 4 ) 0.9 (SO 4 ) 0.01 (NO 3 ) 0.18 For Li 2 (C 2 O 4 ) 0.9 (SO 4 ) 0.01 (NO 3 ) 0.18 Grinding is carried out to obtain the lithium supplementing material with the average particle diameter of 0.3 mu m.
To test the decomposition voltage of the obtained lithium-compensating material, a test battery was prepared using the lithium-compensating material as a battery positive electrode material, and a test battery sample C13 was obtained in the same manner as in example 1.
Example 14
The composition and particle size of the lithium-supplementing material in example 14 were the same as those in example 1, i.e., the lithium-supplementing material was Li having an average particle size of 0.3 μm 2 (C 2 O 4 ) 0.9 (SO 4 ) 0.1 。
In order to test the lithium supplementing effect of the lithium supplementing material in the battery, the lithium supplementing material and the positive electrode material are prepared into a secondary battery, and the preparation method of the secondary battery is as follows:
by LiCoO 2 LiCoO is used as a positive electrode material 2 Mixing the active material with a lithium supplementing material according to the mass ratio of 96.4:3.6, taking acetylene black as a conductive agent, taking polyvinylidene fluoride (PVDF) as a binder and N-methyl pyrrolidone (NMP) as a dispersing agent, uniformly mixing the active material with the acetylene black and the PVDF in the mass ratio of NMP=85:10:5:50 to obtain positive electrode slurry, coating the positive electrode slurry by taking aluminum foil as a current collector, then placing the positive electrode slurry in a 120 ℃ oven for vacuum drying for 24 hours, tabletting and rolling to obtain the positive electrode sheet.
Graphite, carboxymethyl cellulose (CMC) and Styrene Butadiene Rubber (SBR) are mixed according to the mass ratio of 100:3:2, and are coated on copper foil, dried, rolled and cut to obtain the negative plate.
1mol/L LiPF using cellgard 2400 polypropylene porous membrane as membrane 6 The mixed solution (volume ratio=1:1) of Ethylene Carbonate (EC) and dimethyl carbonate (DMC) is an electrolyte; the assembly of the secondary battery was completed in a glove box filled with argon gas, to obtain a secondary battery sample S1.
Example 15
The composition and particle size of the lithium-supplementing material in example 15 were the same as those in example 2, i.e., the lithium-supplementing material was Li having an average particle size of 0.3 μm 2 (C 2 O 4 ) 0.92 (SO 4 ) 0.08 。
A secondary battery sample S2 was prepared in the same manner as in example 14.
Example 16
The composition and particle size of the lithium-supplementing material in example 16 were the same as those in example 3, namely, the lithium-supplementing materialThe material is Li with average grain diameter of 0.3 mu m 2 (C 2 O 4 ) 0.96 (SO 4 ) 0.04 。
A secondary battery sample S3 was produced in the same manner as in example 14.
Example 17
The composition and particle size of the lithium-supplementing material in example 17 were the same as those in example 4, namely, the lithium-supplementing material was Li having an average particle size of 0.3 μm 2 (C 2 O 4 ) 0.8 (SO 4 ) 0.2 。
A secondary battery sample S4 was produced in the same manner as in example 14.
Example 18
The composition and particle size of the lithium-supplementing material in example 18 were the same as those in example 5, i.e., the lithium-supplementing material was Li having an average particle size of 500. Mu.m 2 (C 2 O 4 ) 0.9 (SO 4 ) 0.1 。
A secondary battery sample S5 was produced in the same manner as in example 14.
Example 19
The composition and particle size of the lithium-supplementing material in example 19 were the same as those in example 14, namely, the lithium-supplementing material was Li having an average particle size of 0.3 μm 2 (C 2 O 4 ) 0.9 (SO 4 ) 0.1 . The difference from example 14 is that example 19 is LiCoO 2 And mixing the active material with a lithium supplementing material according to the mass ratio of 90:10, and preparing a secondary battery sample S6 by adopting the same method as in the example 14.
Example 20
The composition and particle size of the lithium-supplementing material in example 20 were the same as those in example 14, i.e., the lithium-supplementing material was Li having an average particle size of 0.3 μm 2 (C 2 O 4 ) 0.9 (SO 4 ) 0.1 . The difference from example 7 is that example 14 is LiCoO 2 And mixing the active material with a lithium supplementing material according to the mass ratio of 99:1, and preparing a secondary battery sample S7 by adopting the same method as in the example 14.
Example 21
Implementation of the embodimentsThe composition and particle size of the lithium-supplementing material in example 21 were the same as those in example 6, namely, the lithium-supplementing material was Li having an average particle size of 0.3 μm 2 (C 2 O 4 ) 0.9 (NO 3 ) 0.2 。
A secondary battery sample S8 was produced in the same manner as in example 14.
Example 22
The composition and particle size of the lithium-supplementing material in example 22 were the same as those in example 7, i.e., the lithium-supplementing material was Li having an average particle size of 0.3 μm 2 (C 2 O 4 ) 0.92 (NO 3 ) 0.16 。
A secondary battery sample S9 was produced in the same manner as in example 14.
Example 23
The composition and particle size of the lithium-supplementing material in example 23 were the same as those in example 8, i.e., the lithium-supplementing material was Li having an average particle size of 0.3 μm 2 (C 2 O 4 ) 0.96 (NO 3 ) 0.08 。
A secondary battery sample S10 was produced in the same manner as in example 14.
Example 24
The composition and particle size of the lithium-supplementing material in example 24 were the same as those in example 9, i.e., the lithium-supplementing material was Li having an average particle size of 0.3 μm 2 (C 2 O 4 ) 0.8 (NO 3 ) 0.4 。
A secondary battery sample S11 was produced in the same manner as in example 14.
Example 25
The composition and particle size of the lithium-supplementing material in example 25 were the same as those in example 10, i.e., the lithium-supplementing material was Li having an average particle size of 500. Mu.m 2 (C 2 O 4 ) 0.9 (NO 3 ) 0.2 。
A secondary battery sample S12 was produced in the same manner as in example 14.
Example 26
The composition and particle size of the lithium-supplementing material in example 26 were the same as those in example 21, i.e., the lithium-supplementing material was Li having an average particle size of 0.3 μm 2 (C 2 O 4 ) 0.9 (NO 3 ) 0.2 . The difference from example 21 is that example 26 is LiCoO 2 And mixed with a lithium supplementing material in a mass ratio of 90:10 to obtain an active material, a secondary battery sample S13 was prepared in the same manner as in example 21.
Example 27
The composition and particle size of the lithium-supplementing material in example 27 were the same as those in example 21, i.e., the lithium-supplementing material was Li having an average particle size of 0.3 μm 2 (C 2 O 4 ) 0.9 (NO 3 ) 0.2 . The difference from example 21 is that example 27 is LiCoO 2 And mixed with a lithium supplementing material in a mass ratio of 99:1 to obtain an active material, and a secondary battery sample S14 was prepared in the same manner as in example 21.
Example 28
The composition and particle size of the lithium-supplementing material in example 28 were the same as those in example 11, i.e., the lithium-supplementing material was Li having an average particle size of 0.3 μm 2 (C 2 O 4 ) 0.9 (SO 4 ) 0.06 (NO 3 ) 0.08 。
A secondary battery sample S15 was produced in the same manner as in example 14.
Example 29
The composition and particle size of the lithium-supplementing material in example 29 were the same as those in example 12, namely, the lithium-supplementing material was Li having an average particle size of 0.3 μm 2 (C 2 O 4 ) 0.9 (SO 4 ) 0.09 (NO 3 ) 0.02 。
A secondary battery sample S16 was produced in the same manner as in example 14.
Example 30
The composition and particle size of the lithium-supplementing material in example 30 were the same as those in example 13, i.e., the lithium-supplementing material was Li having an average particle size of 0.3 μm 2 (C 2 O 4 ) 0.9 (SO 4 ) 0.01 (NO 3 ) 0.18 。
A secondary battery sample S17 was produced in the same manner as in example 14.
Example 31
The composition and particle size of the lithium-supplementing material in example 31 were the same as those in example 28, i.e., the lithium-supplementing material was Li having an average particle size of 0.3 μm 2 (C 2 O 4 ) 0.9 (SO 4 ) 0.06 (NO 3 ) 0.08 . The difference from example 28 is that the secondary battery of example 31 was produced as follows:
by LiCoO 2 The preparation method comprises the steps of uniformly mixing acetylene black and PVDF and NMP=100:2:3:40 in a mass ratio to obtain positive electrode slurry, coating an aluminum foil as a current collector, drying to obtain a positive electrode material layer, uniformly mixing acetylene black and PVDF and NMP=5:2:3:40 in a mass ratio to obtain lithium supplementing slurry, coating the lithium supplementing slurry on the surface of the positive electrode material layer, vacuum drying in a 120 ℃ oven for 24 hours, tabletting, and rolling to obtain the positive electrode plate.
Graphite, carboxymethyl cellulose (CMC) and Styrene Butadiene Rubber (SBR) are mixed according to the mass ratio of 100:3:2, and are coated on copper foil, dried, rolled and cut to obtain the negative plate.
Polypropylene porous membrane is used as a diaphragm, and 1mol/L LiPF is used 6 The mixed solution (volume ratio=1:1) of Ethylene Carbonate (EC) and dimethyl carbonate (DMC) is an electrolyte; the assembly of the secondary battery was completed in a glove box filled with argon gas, to obtain a secondary battery sample S9.
To highlight the beneficial effects of the present application, the following comparative examples are set forth.
Comparative example 1
The lithium supplementing material in comparative example 1 was lithium oxalate having an average particle diameter of 0.3. Mu.m, li 2 C 2 O 4 。
A lithium supplementing material was prepared as a test battery, number of which was DC1, in the same manner as in example 1.
A secondary battery sample DS1 was prepared by using the lithium-compensating material and the positive electrode material in the same manner as in example 14.
Comparative example 2
The lithium supplementing material in comparative example 2 was lithium oxalate having an average particle diameter of 500. Mu.m, li 2 C 2 O 4 。
A lithium supplementing material was prepared as a test battery, number DC2, in the same manner as in example 1.
A secondary battery sample DS2 was prepared by using the lithium-compensating material and the positive electrode material in the same manner as in example 14.
Comparative example 3
The secondary battery of comparative example 3 was not added with a lithium supplementing material, and the positive electrode sheet was prepared from LiCoO 2 LiCoO is used as a positive electrode material 2 Uniformly mixing acetylene black, PVDF and NMP according to the mass ratio of 85:10:5:50 to obtain positive electrode slurry, preparing a positive electrode plate, and preparing a secondary battery sample DS3 by adopting the same method as in example 14.
Effect examples
In order to support the beneficial effects brought by the technical scheme of the embodiment of the application, the following tests are provided:
1) The lithium-compensating materials of examples 1 to 4 were subjected to elemental quantitative analysis using a carbon-sulfur analyzer to obtain the molar ratio of carbon atoms to sulfur atoms (carbon-sulfur ratio) in the lithium-compensating materials, i.e., the relative doping amounts of the lithium-compensating materials, and the test results are shown in table 1.
TABLE 1 relative doping levels of lithium-supplementing materials of examples 1-4
| Experimental group | Carbon to sulfur ratio |
| Example 1 | 18.36 |
| Example 2 | 24.23 |
| Example 3 | 48.36 |
| Example 4 | 8.52 |
The lithium supplement materials of examples 6 to 9 were subjected to quantitative elemental analysis by ion chromatography and gas chromatography, respectively, to determine Li of the same mass 2 (C 2 O 4 ) a (NO 3 ) c Middle NO 3 - Is not limited by the amount of substance and Li 2 (C 2 O 4 ) a (NO 3 ) c CO and CO after decomposition 2 Further, the molar ratio (carbon-nitrogen ratio) of carbon atoms to nitrogen atoms in the lithium-compensating material, that is, the relative doping amount of the lithium-compensating material was obtained, and the test results are shown in table 2.
TABLE 2 relative doping levels of lithium-supplementing materials of examples 6-9
| Experimental group | Carbon to nitrogen ratio |
| Example 6 | 9.15 |
| Example 7 | 11.95 |
| Example 8 | 24.10 |
| Example 9 | 4.16 |
The lithium-supplementing materials of examples 11 to 13 were subjected to elemental quantitative analysis by a carbon-sulfur analyzer, ion chromatography and gas chromatography, respectively, to obtain molar ratios of carbon atoms and sulfur atoms in the lithium-supplementing materials, and the same mass of Li was measured by ion chromatography and gas chromatography 2 (C 2 O 4 ) a (SO 4 ) b (NO 3 ) c Middle NO 3 - Is not limited by the amount of substance and Li 2 (C 2 O 4 ) a (NO 3 ) c CO and CO after decomposition 2 The two test results are combined to obtain the mole ratio of carbon atoms, nitrogen atoms and sulfur atoms in the lithium supplementing material, the mole ratio of a to (b+0.5c) is obtained through conversion, and the test results are shown in table 3.
TABLE 3 relative doping levels of lithium-supplementing materials of examples 11-13
| Experimental group | a/(b+0.5c) |
| Example 11 | 18.17 |
| Example 12 | 18.23 |
| Example 13 | 18.09 |
2) The lithium supplement materials of examples 1 to 13 and comparative examples 1 to 2 were subjected to decomposition performance test, and the decomposition performance of the lithium supplement materials included two aspects: the lithium-free active lithium capacity is the first lithium-free specific capacity, and the lithium-free potential is decomposed, namely the first charging voltage platform. The lower the decomposition platform voltage is, the higher the lithium removal specific capacity is, and the better the lithium supplementing performance of the lithium supplementing material is.
Taking the test batteries of examples 1-13 and comparative examples 1-2, performing a specific charge/discharge capacity test on a charge/discharge tester, testing the specific charge of the lithium supplement material, namely, the lithium removal of the working electrode, specifically, setting the battery in a charging state, namely, the lithium removal of the working electrode, wherein the charging current density is 0.1C, stopping the operation when the battery is charged to a cutoff voltage of 4.6V or 4.8V, calculating the specific charge of the first time, setting the battery in a discharging state, namely, the lithium intercalation of the working electrode, after the first lithium removal is finished, setting the discharging current density to 0.1C, finishing the discharging when the discharging is finished to the cutoff voltage of 3V, and calculating the specific charge of the first time, wherein the specific charge of the first discharging (mAh/g) =the mass of the first discharging capacity/active substance; theoretical first lithium removal specific capacity (mAh/g) =theoretical Li total removal capacity/mass of active substance; first delithiation specific capacity (mAh/g) =first delithiation capacity/mass of active substance.
Referring to fig. 2-5, fig. 2 is a charge-discharge curve diagram of the test battery of examples 1-4, fig. 3 is a charge-discharge curve diagram of the test battery of examples 6-9, fig. 4 is a charge-discharge curve diagram of the test battery of examples 11-13, fig. 5 is a charge-discharge curve diagram of the test battery of comparative examples 1-2, and fig. 2-5 show the Capacity of the battery in mAh, the Voltage in V. In the first charging process, the lithium supplementing material starts to decompose and release active lithium under a certain voltage platform, and the decomposition voltage and the first lithium removal specific capacity of the lithium supplementing material are recorded, and the test results of the test batteries of each example and the comparative example are shown in table 4.
TABLE 4 decomposition Property Table of lithium Material for examples 1-13 and comparative examples 1-2
As can be seen from FIGS. 2 to 5 and Table 4, the decomposition voltages of the lithium supplementing materials of comparative example 1 and comparative example 2 are both largeAt or equal to 4.7V, the lithium supplementing material of the application is added with doping ions SO 4 2- And/or NO 3 - Therefore, the lithium ion doped anode has lower lithium removing potential, and along with the increase of the content of doped ions, the decomposition potential of the lithium-supplementing material is also reduced, and when the lithium-supplementing material is applied to a secondary battery, the lithium supplementing material of the secondary battery can fully release active lithium during the first charge, thereby improving the content of active lithium which is practically available. In addition, as can be seen from the comparison of C5 and C1 and the comparison of C10 and C6 in table 2, the particle size of the lithium supplementing material also affects the decomposition voltage, and the lithium supplementing material with smaller particle size has lower decomposition voltage than the lithium supplementing material with larger particle size; as can be seen from the comparison of C11, C1 and C6, when nitrate radical and sulfate radical are co-doped, the synergistic effect of the nitrate radical and the sulfate radical is more favorable for reducing the decomposition voltage of the material and improving the practically available active lithium capacity.
3) The secondary battery samples of examples 14 to 31 and comparative examples 1 to 3 were subjected to battery performance test for the purpose of verifying the lithium supplementing effect of the lithium supplementing material, and the charge and discharge regimes during the test were: the charge cutoff voltage was 4.55V and the discharge cutoff voltage was 2.00V, and the first charge capacity and the first discharge capacity of each secondary battery sample were recorded, and the first cycle efficiency of the secondary battery was obtained, and the test results thereof are shown in table 5.
Table 5 secondary battery performance tables of examples 14 to 31 and comparative examples 1 to 3
As can be seen from Table 5, the secondary battery of comparative example 3 was not added with a lithium supplementing material, its positive electrode material LiCoO 2 The capacity of the first charge exertion is 845.5mAh, the generation of the negative electrode SEI film consumes about 10.65% of active lithium, so that only 755.5mAh can be back-intercalated in the first discharge, and the lithium supplementing materials added in other experiments can decompose in the charging process to provide active lithium, so that the first effect is improved, however, the lithium supplementing materials of comparative examples 1 and 2 cannot sufficiently decompose in the charging voltage range due to higher decomposition voltage, so that the lithium supplementing effect is limited, and the battery circulatesThe ring performance is poor. In addition, the lithium-supplementing materials in example 17 (cell S4) and example 24 (cell S11) have higher doped ion content, and the sulfate ion or nitrate ion generated by the reaction may form a new crystalline phase structure together with the lithium ion on the positive electrode material due to lower solubility of lithium sulfate or lithium nitrate in the organic solvent, thereby affecting the performance of the cell; in example 19 (battery S6) and example 26 (battery S13), the content of the lithium-replenishing material relative to the positive electrode material was too high, and although sufficient lithium replenishment was achieved to improve the first cycle efficiency of the battery, the energy density of the battery was also reduced; in example 20 (battery S7) and example 27 (battery S14), the content of the lithium supplementing material relative to the positive electrode material was low, the energy density of the battery was high, but the lithium supplementing effect was also slightly poor; the lithium supplementing material in the embodiment 28 (the battery S15) contains nitrate ions and sulfate ions, and the co-doping synergistic effect of the nitrate and the sulfate enables the lithium supplementing material to have good lithium supplementing effect, and compared with the embodiment 29 (the battery S16) and the embodiment 30 (the battery S17), the embodiment 28 (the battery S15) has moderate molar ratio of the nitrate to the sulfate, so that good synergistic effect of the nitrate and the sulfate can be realized, and further the lithium supplementing effect of the lithium supplementing material is improved.
4) The secondary battery samples of examples and comparative examples were subjected to cycle performance test, and the charge and discharge regimes during the test were: the charge cut-off voltage is 4.45V, the discharge cut-off voltage is 2.75V, the charge and discharge current is 1C, and the charge and discharge are set for 500 times of circulation. Referring to fig. 6, fig. 6 is a graph comparing the cycle performance of the secondary battery S1 of example 14 and that of the secondary battery DS1 of comparative example 1, and as can be seen from fig. 6, the secondary battery of comparative example 1 using lithium oxalate as the lithium supplementing material has a capacity retention rate of only 30% after 500 cycles and an apparent capacity of unstable in the previous 100 cycles, because unreacted lithium oxalate slowly reacts and generates gas during the cycle after the formation, so that the material on the electrode sheet is loosened, and the electroactive material loses electrical contact with the conductive agent, resulting in capacity decrease. Example 14 use and Li 2 (C 2 O 4 ) 0.9 (SO 4 ) 0.1 As the secondary battery of the lithium supplementing material, the oxalate in the lithium supplementing material reacts more fully during the formation periodDividing into remaining doping ions SO 4 2- No reaction occurs, and the cycle performance is relatively good. Therefore, the sulfate radical doped in lithium oxalate can reduce the decomposition voltage of the material and improve the cycle performance of the battery.
Referring to fig. 7, fig. 7 is a graph comparing the cycle performance of the secondary battery S8 of example 21 and the secondary battery DS1 of comparative example 1, and as can be seen from fig. 7, example 21 employs Li 2 (C 2 O 4 ) 0.9 (NO 3 ) 0.2 The secondary battery as the lithium-supplementing material had better cycle performance than the secondary battery of comparative example 1, in particular, since the oxalate in the lithium-supplementing material reacted more fully during formation, while the remaining doped ion NO 3 - No reaction occurs, and the cycle performance is relatively good. Therefore, the nitrate radical doped in lithium oxalate can reduce the decomposition voltage of the material and improve the cycle performance of the battery.
Referring to fig. 8, fig. 8 is a graph comparing the cycle performance of the secondary battery S15 of example 28 with that of the secondary battery DS1 of comparative example 1, and as can be seen from fig. 8, li is used in example 28 2 (C 2 O 4 ) 0.9 (SO 4 ) 0.06 (NO 3 ) 0.08 The secondary battery as a lithium supplementing material had better cycle performance than the secondary battery of comparative example 1.
5) The secondary battery samples of the examples and the comparative examples were subjected to a cyclic gassing test, and the charge and discharge regimes during the test were as follows: the charge cut-off voltage is 4.45V, the discharge cut-off voltage is 2.75V, the charge and discharge current is 1C, the charge and discharge are set for 500 cycles, and when the cycle is carried out for 50 times, the battery is taken down and the gas production amount is measured by adopting a drainage method. Referring to fig. 9, fig. 9 is a graph comparing the gas production of the secondary battery S1 of example 14 and that of the secondary battery DS1 of comparative example 1, and as can be seen from fig. 9, in the case of comparable battery capacity, the secondary battery cycle gas production of comparative example 1 using lithium oxalate as a lithium supplementing material is significantly higher than that of the secondary battery of example 14 of the present application. This is due to the lithium supplementing material Li of example 14 2 (C 2 O 4 ) 0.9 (SO 4 ) 0.1 The valence state of S element in the medium doped ion sulfate ion is as followsThe highest valence state of the lithium-supplementing material is difficult to decompose continuously under high voltage, and the residual components of the lithium-supplementing material after formation mainly are lithium sulfate, so that the lithium-supplementing material cannot decompose continuously in subsequent battery cycles, and the circulating gas yield is reduced.
Referring to fig. 10, fig. 10 is a graph showing comparison of the gas production of the secondary battery S8 of example 21 and the secondary battery DS1 of comparative example 1, and it can be seen from fig. 10 that in the case of comparable battery capacity, the secondary battery cycle gas production of comparative example 1 using lithium oxalate as the lithium supplementing material is significantly higher than that of the secondary battery of example 21 of the present application, because of the lithium supplementing material Li of example 21 2 (C 2 O 4 ) 0.9 (NO 3 ) 0.2 The valence state of N element in the medium doped ion nitrate is the highest valence state which can be achieved by the medium doped ion nitrate, the medium doped ion nitrate is difficult to decompose continuously under high voltage, the residual component of the lithium supplementing material after formation is mainly lithium nitrate, and the medium doped ion nitrate cannot decompose continuously in the subsequent battery cycle, so that the circulating gas yield is reduced.
Referring to fig. 11, fig. 11 is a graph comparing the gassing of secondary battery S15 of example 28 with that of secondary battery DS1 of comparative example 1, and as can be seen from fig. 11, example 28 employs Li 2 (C 2 O 4 ) 0.9 (SO 4 ) 0.06 (NO 3 ) 0.08 The secondary battery as a lithium supplementing material had a lower cycle gas yield than the secondary battery of comparative example 1.
The foregoing is a preferred embodiment of the present application and is not to be construed as limiting the scope of the present application. It should be noted that modifications and adaptations to the principles of the present application may occur to one skilled in the art and are intended to be comprehended within the scope of the present application.
Claims (10)
1. A lithium supplementing material is characterized by comprising a chemical formula of Li 2 (C 2 O 4 ) a (SO 4 ) b (NO 3 ) c Wherein a+b+0.5c=1, 0 < a < 1, b.gtoreq.0, c.gtoreq.0.
2. The lithium-supplementing material according to claim 1, wherein a ratio of a to (b+0.5c) is 9 or more.
3. The lithium-supplementing material according to claim 1 or 2, wherein b > 0 and c > 0.
4. A lithium-supplementing material according to any one of claims 1 to 3, wherein 1 < c/b < 10.
5. The lithium-supplementing material according to any one of claims 1 to 4, wherein an average particle diameter of the lithium-supplementing material is 1nm to 20 μm.
6. A positive electrode sheet comprising an active material and the lithium supplementing material according to any one of claims 1 to 5.
7. The positive electrode tab of claim 6, wherein the positive electrode tab comprises a current collector and an active material layer disposed on the current collector, the active material layer comprising the active material and the lithium-compensating material;
Or the positive pole piece comprises a current collector, a positive pole material layer and a lithium supplementing layer which are sequentially arranged, wherein the positive pole material layer comprises the active material, and the lithium supplementing layer comprises the lithium supplementing material.
8. The positive electrode sheet according to claim 6, wherein the mass ratio of the lithium supplementing material to the active material is 1 (5-1000).
9. A secondary battery comprising a positive electrode, a negative electrode, a separator, and an electrolyte, wherein the positive electrode comprises the positive electrode sheet according to any one of claims 6 to 8.
10. An electronic device, characterized in that the electronic device comprises the secondary battery according to claim 9.
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