CN118142560A - Catalyst, composite lithium supplementing material, and preparation method and application thereof - Google Patents
Catalyst, composite lithium supplementing material, and preparation method and application thereof Download PDFInfo
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- CN118142560A CN118142560A CN202410242266.0A CN202410242266A CN118142560A CN 118142560 A CN118142560 A CN 118142560A CN 202410242266 A CN202410242266 A CN 202410242266A CN 118142560 A CN118142560 A CN 118142560A
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- lithium
- carbon
- catalyst
- metal compound
- carbon material
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- 239000000463 material Substances 0.000 title claims abstract description 256
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 title claims abstract description 240
- 229910052744 lithium Inorganic materials 0.000 title claims abstract description 240
- 239000003054 catalyst Substances 0.000 title claims abstract description 187
- 239000002131 composite material Substances 0.000 title claims abstract description 88
- 230000001502 supplementing effect Effects 0.000 title claims abstract description 75
- 238000002360 preparation method Methods 0.000 title claims abstract description 21
- 239000003575 carbonaceous material Substances 0.000 claims abstract description 202
- 150000002736 metal compounds Chemical class 0.000 claims abstract description 116
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 101
- 125000005842 heteroatom Chemical group 0.000 claims abstract description 88
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 29
- 229910021393 carbon nanotube Inorganic materials 0.000 claims description 67
- 239000002041 carbon nanotube Substances 0.000 claims description 65
- 238000002156 mixing Methods 0.000 claims description 29
- 229910052751 metal Inorganic materials 0.000 claims description 26
- 239000002184 metal Substances 0.000 claims description 26
- 239000007774 positive electrode material Substances 0.000 claims description 26
- 238000011068 loading method Methods 0.000 claims description 23
- 239000012702 metal oxide precursor Substances 0.000 claims description 21
- 239000002245 particle Substances 0.000 claims description 19
- 239000011247 coating layer Substances 0.000 claims description 13
- 125000000524 functional group Chemical group 0.000 claims description 13
- 239000002994 raw material Substances 0.000 claims description 13
- 229910052755 nonmetal Inorganic materials 0.000 claims description 10
- 238000001354 calcination Methods 0.000 claims description 9
- 229920000049 Carbon (fiber) Polymers 0.000 claims description 8
- 239000004917 carbon fiber Substances 0.000 claims description 8
- 230000007547 defect Effects 0.000 claims description 8
- 229910044991 metal oxide Inorganic materials 0.000 claims description 8
- 150000004706 metal oxides Chemical class 0.000 claims description 8
- 229910021389 graphene Inorganic materials 0.000 claims description 5
- 239000011149 active material Substances 0.000 claims description 4
- 239000006229 carbon black Substances 0.000 claims description 4
- 239000003273 ketjen black Substances 0.000 claims description 4
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 4
- 229910052976 metal sulfide Inorganic materials 0.000 claims description 3
- 239000002243 precursor Substances 0.000 claims description 3
- 150000001721 carbon Chemical group 0.000 claims description 2
- 230000003197 catalytic effect Effects 0.000 abstract description 44
- 238000000354 decomposition reaction Methods 0.000 abstract description 16
- 230000002829 reductive effect Effects 0.000 abstract description 11
- 229940125797 compound 12 Drugs 0.000 description 63
- 125000004433 nitrogen atom Chemical group N* 0.000 description 26
- 125000004429 atom Chemical group 0.000 description 25
- 238000000034 method Methods 0.000 description 19
- 230000000052 comparative effect Effects 0.000 description 18
- 239000000126 substance Substances 0.000 description 18
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 15
- 229910001416 lithium ion Inorganic materials 0.000 description 15
- 125000004432 carbon atom Chemical group C* 0.000 description 12
- 238000006243 chemical reaction Methods 0.000 description 12
- 239000010410 layer Substances 0.000 description 10
- 230000008569 process Effects 0.000 description 9
- 230000000694 effects Effects 0.000 description 8
- 239000002253 acid Substances 0.000 description 7
- 239000003795 chemical substances by application Substances 0.000 description 7
- 238000001035 drying Methods 0.000 description 7
- 238000005406 washing Methods 0.000 description 7
- 238000007600 charging Methods 0.000 description 6
- 238000011065 in-situ storage Methods 0.000 description 6
- 238000006557 surface reaction Methods 0.000 description 6
- 229910052796 boron Inorganic materials 0.000 description 5
- 238000006555 catalytic reaction Methods 0.000 description 5
- 239000011248 coating agent Substances 0.000 description 5
- 238000000576 coating method Methods 0.000 description 5
- 229910052750 molybdenum Inorganic materials 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 4
- 229910019142 PO4 Inorganic materials 0.000 description 4
- 230000008901 benefit Effects 0.000 description 4
- 239000008367 deionised water Substances 0.000 description 4
- 229910021641 deionized water Inorganic materials 0.000 description 4
- 239000003792 electrolyte Substances 0.000 description 4
- 238000000227 grinding Methods 0.000 description 4
- 229910052760 oxygen Inorganic materials 0.000 description 4
- 238000006479 redox reaction Methods 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- 230000002195 synergetic effect Effects 0.000 description 4
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 description 3
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 239000011230 binding agent Substances 0.000 description 3
- 238000005229 chemical vapour deposition Methods 0.000 description 3
- 238000005253 cladding Methods 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 239000006258 conductive agent Substances 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- YNQRWVCLAIUHHI-UHFFFAOYSA-L dilithium;oxalate Chemical compound [Li+].[Li+].[O-]C(=O)C([O-])=O YNQRWVCLAIUHHI-UHFFFAOYSA-L 0.000 description 3
- 230000006872 improvement Effects 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
- 239000011572 manganese Chemical group 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 3
- 239000010452 phosphate Substances 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- 125000004434 sulfur atom Chemical group 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 2
- 229920001661 Chitosan Polymers 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- 229910013870 LiPF 6 Inorganic materials 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 235000014787 Vitis vinifera Nutrition 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- APUPEJJSWDHEBO-UHFFFAOYSA-P ammonium molybdate Chemical compound [NH4+].[NH4+].[O-][Mo]([O-])(=O)=O APUPEJJSWDHEBO-UHFFFAOYSA-P 0.000 description 2
- 239000011609 ammonium molybdate Substances 0.000 description 2
- 229940010552 ammonium molybdate Drugs 0.000 description 2
- 235000018660 ammonium molybdate Nutrition 0.000 description 2
- 229910003481 amorphous carbon Inorganic materials 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000009835 boiling Methods 0.000 description 2
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- 239000012018 catalyst precursor Substances 0.000 description 2
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- 238000001914 filtration Methods 0.000 description 2
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- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 2
- AMWRITDGCCNYAT-UHFFFAOYSA-L hydroxy(oxo)manganese;manganese Chemical compound [Mn].O[Mn]=O.O[Mn]=O AMWRITDGCCNYAT-UHFFFAOYSA-L 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 230000000670 limiting effect Effects 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 229940071125 manganese acetate Drugs 0.000 description 2
- UOGMEBQRZBEZQT-UHFFFAOYSA-L manganese(2+);diacetate Chemical compound [Mn+2].CC([O-])=O.CC([O-])=O UOGMEBQRZBEZQT-UHFFFAOYSA-L 0.000 description 2
- 239000011259 mixed solution Substances 0.000 description 2
- 229910017604 nitric acid Inorganic materials 0.000 description 2
- 125000004437 phosphorous atom Chemical group 0.000 description 2
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- 239000011164 primary particle Substances 0.000 description 2
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- 238000001179 sorption measurement Methods 0.000 description 2
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- 229910052717 sulfur Inorganic materials 0.000 description 2
- 229910052720 vanadium Inorganic materials 0.000 description 2
- IXPNQXFRVYWDDI-UHFFFAOYSA-N 1-methyl-2,4-dioxo-1,3-diazinane-5-carboximidamide Chemical compound CN1CC(C(N)=N)C(=O)NC1=O IXPNQXFRVYWDDI-UHFFFAOYSA-N 0.000 description 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 1
- 125000003184 C60 fullerene group Chemical group 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- CTENFNNZBMHDDG-UHFFFAOYSA-N Dopamine hydrochloride Chemical compound Cl.NCCC1=CC=C(O)C(O)=C1 CTENFNNZBMHDDG-UHFFFAOYSA-N 0.000 description 1
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 description 1
- 229910011763 Li2 O Inorganic materials 0.000 description 1
- 229910011017 Li2CoO2 Inorganic materials 0.000 description 1
- 229910003349 Li2CuO2 Inorganic materials 0.000 description 1
- 229910010077 Li2MnO2 Inorganic materials 0.000 description 1
- 229910008722 Li2NiO2 Inorganic materials 0.000 description 1
- 229910001216 Li2S Inorganic materials 0.000 description 1
- 229910010699 Li5FeO4 Inorganic materials 0.000 description 1
- 229910010648 Li6CoO4 Inorganic materials 0.000 description 1
- 229910010889 Li6ZnO4 Inorganic materials 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- 229910016759 Ni0.5Mn1.5O4 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- 239000002033 PVDF binder Substances 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- 229920001328 Polyvinylidene chloride Polymers 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 241000219095 Vitis Species 0.000 description 1
- 235000009754 Vitis X bourquina Nutrition 0.000 description 1
- 235000012333 Vitis X labruscana Nutrition 0.000 description 1
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- PFYQFCKUASLJLL-UHFFFAOYSA-N [Co].[Ni].[Li] Chemical compound [Co].[Ni].[Li] PFYQFCKUASLJLL-UHFFFAOYSA-N 0.000 description 1
- HFCVPDYCRZVZDF-UHFFFAOYSA-N [Li+].[Co+2].[Ni+2].[O-][Mn]([O-])(=O)=O Chemical compound [Li+].[Co+2].[Ni+2].[O-][Mn]([O-])(=O)=O HFCVPDYCRZVZDF-UHFFFAOYSA-N 0.000 description 1
- QRVIVVYHHBRVQU-UHFFFAOYSA-H [Li+].[V+5].[O-]P([O-])(F)=O.[O-]P([O-])(F)=O.[O-]P([O-])(F)=O Chemical compound [Li+].[V+5].[O-]P([O-])(F)=O.[O-]P([O-])(F)=O.[O-]P([O-])(F)=O QRVIVVYHHBRVQU-UHFFFAOYSA-H 0.000 description 1
- 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 1
- XHCLAFWTIXFWPH-UHFFFAOYSA-N [O-2].[O-2].[O-2].[O-2].[O-2].[V+5].[V+5] Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[V+5].[V+5] XHCLAFWTIXFWPH-UHFFFAOYSA-N 0.000 description 1
- 239000006230 acetylene black Substances 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 1
- 239000001768 carboxy methyl cellulose Substances 0.000 description 1
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 1
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 1
- 238000003421 catalytic decomposition reaction Methods 0.000 description 1
- 239000010406 cathode material Substances 0.000 description 1
- 229910000428 cobalt oxide Inorganic materials 0.000 description 1
- IVMYJDGYRUAWML-UHFFFAOYSA-N cobalt(ii) oxide Chemical compound [Co]=O IVMYJDGYRUAWML-UHFFFAOYSA-N 0.000 description 1
- 238000010280 constant potential charging Methods 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
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- 238000005336 cracking Methods 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- QHGJSLXSVXVKHZ-UHFFFAOYSA-N dilithium;dioxido(dioxo)manganese Chemical compound [Li+].[Li+].[O-][Mn]([O-])(=O)=O QHGJSLXSVXVKHZ-UHFFFAOYSA-N 0.000 description 1
- 229960001149 dopamine hydrochloride Drugs 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 239000008151 electrolyte solution Substances 0.000 description 1
- 230000003628 erosive effect Effects 0.000 description 1
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 238000003837 high-temperature calcination Methods 0.000 description 1
- 239000001866 hydroxypropyl methyl cellulose Substances 0.000 description 1
- 235000010979 hydroxypropyl methyl cellulose Nutrition 0.000 description 1
- 229920003088 hydroxypropyl methyl cellulose Polymers 0.000 description 1
- UFVKGYZPFZQRLF-UHFFFAOYSA-N hydroxypropyl methyl cellulose Chemical compound OC1C(O)C(OC)OC(CO)C1OC1C(O)C(O)C(OC2C(C(O)C(OC3C(C(O)C(O)C(CO)O3)O)C(CO)O2)O)C(CO)O1 UFVKGYZPFZQRLF-UHFFFAOYSA-N 0.000 description 1
- 229910052909 inorganic silicate Inorganic materials 0.000 description 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 230000002427 irreversible effect Effects 0.000 description 1
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 description 1
- 229910052808 lithium carbonate Inorganic materials 0.000 description 1
- PEXNRZDEKZDXPZ-UHFFFAOYSA-N lithium selenidolithium Chemical compound [Li][Se][Li] PEXNRZDEKZDXPZ-UHFFFAOYSA-N 0.000 description 1
- DVATZODUVBMYHN-UHFFFAOYSA-K lithium;iron(2+);manganese(2+);phosphate Chemical compound [Li+].[Mn+2].[Fe+2].[O-]P([O-])([O-])=O DVATZODUVBMYHN-UHFFFAOYSA-K 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 229910052748 manganese Chemical group 0.000 description 1
- 229940082328 manganese acetate tetrahydrate Drugs 0.000 description 1
- CESXSDZNZGSWSP-UHFFFAOYSA-L manganese(2+);diacetate;tetrahydrate Chemical compound O.O.O.O.[Mn+2].CC([O-])=O.CC([O-])=O CESXSDZNZGSWSP-UHFFFAOYSA-L 0.000 description 1
- 238000003801 milling Methods 0.000 description 1
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- 229910000476 molybdenum oxide Inorganic materials 0.000 description 1
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 1
- 229910000480 nickel oxide Inorganic materials 0.000 description 1
- 229910000484 niobium oxide Inorganic materials 0.000 description 1
- URLJKFSTXLNXLG-UHFFFAOYSA-N niobium(5+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Nb+5].[Nb+5] URLJKFSTXLNXLG-UHFFFAOYSA-N 0.000 description 1
- 235000006408 oxalic acid Nutrition 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000006864 oxidative decomposition reaction Methods 0.000 description 1
- PQQKPALAQIIWST-UHFFFAOYSA-N oxomolybdenum Chemical compound [Mo]=O PQQKPALAQIIWST-UHFFFAOYSA-N 0.000 description 1
- GNRSAWUEBMWBQH-UHFFFAOYSA-N oxonickel Chemical compound [Ni]=O GNRSAWUEBMWBQH-UHFFFAOYSA-N 0.000 description 1
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- 229910052698 phosphorus Inorganic materials 0.000 description 1
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- 239000004810 polytetrafluoroethylene Substances 0.000 description 1
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- 229910052721 tungsten Inorganic materials 0.000 description 1
- 238000001291 vacuum drying Methods 0.000 description 1
- 229910001935 vanadium oxide Inorganic materials 0.000 description 1
- 125000005287 vanadyl group Chemical group 0.000 description 1
- 230000003313 weakening effect Effects 0.000 description 1
Landscapes
- Catalysts (AREA)
Abstract
The invention provides a catalyst, a composite lithium supplementing material, a preparation method and application thereof, wherein the catalyst comprises a carbon material and a metal compound; wherein, the carbon material is doped with hetero atoms of non-carbon elements; and metal compounds are grown on the carbon material. The invention also provides a composite lithium supplementing material, which comprises the lithium-rich material and the catalyst, wherein the catalyst is combined with the lithium-rich material. The catalyst provided by the invention can solve the problems of low catalytic activity or poor conductivity of the catalyst. The composite lithium supplementing material provided by the invention can load more catalysts, and the catalytic effect of the catalysts on the lithium-rich material is enhanced, so that the decomposition voltage of the lithium-rich material is reduced more obviously.
Description
Technical Field
The invention relates to the technical field of secondary batteries, in particular to a catalyst, a composite lithium supplementing material, a preparation method and application thereof.
Background
In the first charge and discharge process of the battery, the electrolyte can undergo a reduction decomposition reaction on the surface of the negative electrode, and a layer of solid electrolyte interface film (SEI film) is formed, and a large amount of active lithium is consumed by the generation of the SEI film, so that the actual energy density of the battery is reduced compared with a theoretical calculation value. In the cyclic charge and discharge process of the battery, active lithium is continuously consumed by cracking and crushing of positive electrode active material particles, thickening and repairing of an SEI film, so that the cyclic performance of the battery is continuously reduced. In order to further improve the energy density and the cycle performance of the battery, the problems of low energy density, low first-turn efficiency, poor cycle life and the like of the battery can be effectively relieved by adding the lithium supplementing material into the positive electrode plate.
However, the existing lithium supplementing material has the problems of higher decomposition voltage, poor conductivity and the like, so that the lithium supplementing material cannot fully release lithium ions under the low-voltage condition, and the transmission path of electrons and ions in the lithium supplementing material is longer, so that the dynamic performance is poor. Therefore, a catalyst is added to the existing lithium supplementing material to reduce the lithium removal potential of the lithium rich material in the lithium supplementing material. However, most catalysts have limited catalytic activity, and it is difficult to achieve the desired effect, and the catalyst has limited improvement in conductivity of the lithium-rich material, so how to provide a catalyst having high catalytic activity and conductivity becomes critical.
Disclosure of Invention
The invention aims to provide a catalyst, a composite lithium supplementing material, a preparation method and application thereof, and solves the problems of low catalytic activity or poor conductivity of the catalyst.
In order to achieve the purpose of the invention, the invention provides the following technical scheme:
In a first aspect, the present invention provides a catalyst comprising a carbon material and a metal compound; wherein, the carbon material is doped with hetero atoms of non-carbon elements; and the metal compound grows on the carbon material.
The catalyst provided by the application comprises a carbon material and a metal compound, wherein hetero atoms are doped in the carbon material, and the metal compound grows on the carbon material, and has the following advantages: 1) The catalyst has conductivity and catalytic capability, and only catalytic compounds exist in the existing catalytic material, so that the catalytic material only provides catalytic capability, the application combines the carbon material and the metal compound, and the catalyst has conductivity by utilizing the high conductivity of the carbon material, so that no conductive material is required to be added after the catalyst is combined with the lithium-rich material; 2) The carbon material in the catalyst has higher conductivity and catalytic activity, and the heteroatom doping can change the electronic structure and chemical property of the carbon material, so that the conductivity, catalytic activity and the like of the carbon material are improved, and compared with the pure carbon material in the prior art, the doped carbon material can have a synergistic effect with a metal compound, so that the comprehensive performance of the catalyst is improved; 3) The metal compound directly grows on the carbon material, the manufacturing process is simple, the bonding strength of the metal compound and the carbon material is high, and compared with a composite catalyst simply mixed in the prior art, the metal compound is not easy to fall off from the carbon material, so that the catalyst has high stability in use; 4) The metal compound is loaded on the carbon material in a direct growth mode, so that larger metal compound loading capacity can be obtained on the carbon material, and compared with a physical mixing mode, the metal compound is easier to form a close-packed structure, and is more densely attached, so that the loading capacity of the metal compound on the carbon material is increased, and therefore, the metal compound content in the catalyst provided by the application is higher, and the catalytic efficiency is higher.
In one embodiment, the loading of the metal compound per unit area of the carbon material is greater than or equal to 10wt%.
In a second aspect, the present invention provides a composite lithium-supplementing material comprising a lithium-rich material and the catalyst provided in the first aspect, the catalyst being associated with the lithium-rich material.
The catalyst provided by the embodiment of the invention is combined with the lithium-rich material to obtain the composite lithium-supplementing material, and the composite lithium-supplementing material has the following effects: 1) The lithium-rich material can be provided with a high-loading catalyst, and the catalyst-based structure has the advantages that the metal compound content in the catalyst is higher, so that more catalysts are arranged in the composite lithium-rich material under the same volume, the catalysis effect of the catalyst on the lithium-rich material is enhanced, and the decomposition voltage drop of the lithium-rich material is more obvious; 2) The combination of the lithium-rich material and the catalyst is tighter, and because the carbon material in the catalyst can provide larger specific surface area, the carbon material has more active sites, the lithium-rich material, the carbon material and the metal compound are firmly combined together by utilizing intermolecular acting force, the metal compound is not easy to fall off from the carbon material, and the whole catalyst is not easy to fall off from the lithium-rich material, so that the catalytic effect of the catalyst is enhanced in the process of catalyzing the lithium-rich material by the catalyst, and the decomposition voltage of the lithium-rich material can be further reduced.
In one embodiment, the heteroatom of the non-carbon element comprises a nonmetallic heteroatom that is chemically bonded to a carbon atom of the carbon material.
In one embodiment, the heteroatom of the non-carbon element further comprises a metal heteroatom, the metal heteroatom being covalently bonded to the non-metal heteroatom.
In one embodiment, the nonmetallic heteroatom includes at least one of an N atom, a P atom, an S atom, a B atom.
In one embodiment, the metal heteroatom includes at least one of a Mo atom, a Co atom, and a Mn atom.
In one embodiment, the carbon material has active sites that include carbon surface defects and/or functional groups to which the metal compound is bound.
In one embodiment, the carbon material has a three-dimensional network structure, and the metal compound is bonded to a carbon skeleton of the carbon material of the three-dimensional network structure.
In one embodiment, the mass ratio of the carbon material to the metal compound is 100: (10-150).
In one embodiment, the non-carbon heteroatoms are present in an amount of 0.1wt% to 5wt% of the carbon material.
In one embodiment, the carbon material comprises at least one of carbon nanotubes, carbon fibers, graphene, carbon black, ketjen black.
In one embodiment, the metal compound includes at least one of a metal oxide, a metal carbide, and a metal sulfide.
In one embodiment, the catalyst is coated on the outer surface of the lithium-rich material and forms a coating layer.
In one embodiment, the D50 particle size of the lithium-rich material is 100nm to 10 μm.
In one embodiment, the mass ratio of the catalyst in the composite lithium supplementing material is 5-40 wt%.
In a third aspect, the present invention also provides a method for preparing a composite lithium supplementing material, including: mixing and reacting a carbon material and a heteroatom raw material of a non-carbon element to obtain a carbon material doped with a heteroatom of the non-carbon element; mixing and reacting the carbon material and a metal oxide precursor to obtain a catalyst, wherein the metal oxide precursor is converted into a metal compound and grows on the carbon material; and mixing and calcining the catalyst and the lithium-rich material together to obtain the composite lithium-supplementing material.
According to the preparation method of the composite lithium supplementing material, the heteroatom is doped in the carbon material, and the metal oxide precursor is utilized to convert the metal compound in situ, so that the catalyst can have conductivity and catalytic capability at the same time; and through heteroatom doping, the carbon material in the catalyst has higher conductivity and catalytic activity, and the doped carbon material can play a synergistic effect with a metal compound, so that the comprehensive performance of the catalyst is improved.
In a fourth aspect, the present invention further provides a positive electrode material, where the positive electrode material includes a positive electrode active material and a lithium supplementing material, and the lithium supplementing material includes the composite lithium supplementing material according to the first aspect, or the positive electrode material includes a composite lithium supplementing material obtained by the preparation method of the composite lithium supplementing material according to the second aspect.
In a fifth aspect, the present invention also provides a secondary battery comprising a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode, the positive electrode comprising the positive electrode material of the third aspect.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the description below are only some embodiments of the invention, and that other drawings can be obtained from them without inventive effort for a person skilled in the art.
FIG. 1 is a schematic view of the appearance of a catalyst according to one embodiment;
FIG. 2 is a schematic illustration of a heteroatom attached to a carbon material of one embodiment;
FIG. 3 is an SEM of a catalyst of one embodiment;
FIG. 4 is a schematic cross-sectional view of a composite lithium-supplementing material of an embodiment;
FIG. 5 is a flow chart of the preparation of a composite lithium-supplementing material according to one embodiment;
fig. 6 is a flow chart of the preparation of a composite lithium-supplementing material according to another embodiment.
Detailed Description
The following description of the embodiments of the present invention 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 embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, are intended to fall within the scope of the present invention.
It will be understood that when an element is referred to as being "fixed to" another element, it can be directly on the other element or intervening elements may also be present. When a component is considered to be "connected" to another component, it can be directly connected to the other component or intervening components may also be present.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.
Some embodiments of the present invention are described in detail below with reference to the accompanying drawings. The following embodiments and features of the embodiments may be combined with each other without conflict.
The invention provides a catalyst 10, please refer to fig. 1 and 3, comprising a carbon material 11 and a metal compound, wherein the carbon material 11 is doped with hetero atoms other than carbon; and a metal compound 12 is grown on the carbon material 11.
Specifically, the catalyst 10 acts on the lithium-rich material to catalyze the reduction of the delithiation potential of the lithium-rich material and to increase the electrical conductivity of the lithium-rich material. It will be appreciated that the catalyst 10 may be mixed with and in contact with a lithium-rich material to achieve a catalytic effect. The carbon material 11 in the catalyst 10 may be used to increase the electron conductivity and ion conductivity of the lithium-rich material, and the metal compound 12 in the catalyst 10 may be used to decrease the delithiation potential of the lithium-rich material, such that the lithium-rich material may release lithium ions at a lower potential.
In one embodiment, the carbon material 11 includes at least one of carbon nanotubes, carbon fibers, graphene, carbon black, ketjen black. It will be appreciated that the specific form of the carbon material 11 is not limited and includes amorphous carbon and amorphous carbon, and the primary purpose of the carbon material 11 is to increase the electrical conductivity of the catalyst 10 and thus the electrical conductivity of the composite material after the catalyst 10 is mixed with the lithium-rich material.
Optionally, the carbon material 11 is doped with heteroatoms of non-carbon elements, which may be non-metallic heteroatoms or metallic heteroatoms. The heteroatoms may be attached to carbon atoms in the carbon material 11 by chemical bonds. Doping the carbon material 11 with heteroatoms may increase the conductivity of the carbon material 11, thereby increasing the conductivity of the catalyst 10, compared to the common carbon material 11, and may increase the conductivity of the lithium-rich material after the catalyst 10 is combined with the lithium-rich material.
In addition, the carbon material 11 doped by the hetero atoms can be endowed with catalytic capability and has higher catalytic activity. For example, the boron doped carbon material 11 has excellent catalytic performance and can be used for oxidation reaction and the like. Furthermore, the heteroatom-doped carbon material 11 also has mechanical properties that are superior to those of the pure carbon material 11. For example, boron atom doped carbon nanotubes are harder, have better toughness and have higher compressive strength than pure carbon nanotubes; the sulfur atom doped carbon nano tube has good toughness and flexural modulus, and the nitrogen atom doped carbon nano tube has higher mechanical strength and heat resistance.
Alternatively, the heteroatom-doped carbon material 11 may be prepared by a variety of methods, such as physical milling mixing, chemical vapor deposition, arc discharge, laser evaporation, and the like.
In one embodiment, the metal compound 12 includes at least one of a metal oxide, a metal carbide, and a metal sulfide. Alternatively, the metal compound 12 may have a granular structure.
In a specific embodiment, the metal compound 12 is a metal oxide, and the chemical formula of the metal oxide includes A xOy, A includes at least one of Mo, W, V, ti, fe, co, ni, mn, cr, cu, zn, 1.ltoreq.x.ltoreq.3, 1.ltoreq.y.ltoreq.3. For example, the metal compound may include manganese oxide, nickel oxide, cobalt oxide, iron oxide, titanium oxide, molybdenum oxide, vanadium oxide, or niobium oxide.
Alternatively, the metal compound 12 is grown on the carbon material 11, wherein the grown metal compound 12 and the carbon material 11 may be connected by chemical bonds, or may be connected without chemical bonds therebetween. Wherein, no chemical bond is formed between the metal compound 12 and the carbon material 11, and the metal compound 12 and the carbon material 11 may be connected by intermolecular force. For example, the metal compound 12 may be formed by in situ reaction of a metal oxide precursor. It should be explained that the in situ reaction formation is as follows: the metal oxide precursor (e.g., hydroxide or salt) is first combined with the carbon material 11, and then sintered at a high temperature to convert the metal oxide precursor into the metal compound 12, where the spatial position of the metal compound 12 is unchanged compared with the metal oxide precursor.
In a specific example, for the preparation of MnO from manganese acetate, manganese acetate is first adsorbed on carbon material 11, then hydrolyzed to form Mn (OH) 2, then washed, dried and calcined, and Mn (OH) 2 is decomposed to MnO. Of course, precursors to other metal oxides may also be employed in other embodiments.
The catalyst 10 provided by the application comprises a carbon material 11 and a metal compound 12, wherein hetero atoms are doped in the carbon material 11, and the metal compound 12 grows on the carbon material 11, and the catalyst 10 provided by the application has the following advantages: 1) The catalyst 10 has conductivity and catalytic capability at the same time, only catalytic compounds exist in the existing catalytic materials, so the catalytic materials only provide catalytic capability, the application combines the carbon material 11 and the metal compound 12, and the catalyst 10 has conductivity by utilizing the high conductivity of the carbon material 11, and after the catalyst 10 is combined with the lithium-rich material, no conductive material is needed to be added; 2) The carbon material 11 in the catalyst 10 has higher conductivity and catalytic activity, and the heteroatom doping can change the electronic structure and chemical property of the carbon material 11, so that the conductivity, catalytic activity and the like of the carbon material 11 are improved, and compared with the pure carbon material 11 in the prior art, the doped carbon material 11 can have a synergistic effect with the metal compound 12, so that the comprehensive performance of the catalyst 10 is improved; 3) The manufacturing process that the metal compound 12 grows on the carbon material 11 directly is simple, and the bonding strength of the metal compound 12 and the carbon material 11 is high, compared with the composite catalyst 10 simply mixed in the prior art, the metal compound 12 provided by the application is not easy to fall off from the carbon material 11, so that the stability of the catalyst 10 in use is high; 4) By directly growing the metal compound 12 on the carbon material 11, a larger load of the metal compound 12 on the carbon material 11 can be obtained, and compared with a physical mixing mode, the grown metal compound 12 is easier to form a close-packed structure, and the metal compound 12 is more densely attached, so that the load of the metal compound 12 on the carbon material 11 is increased, and therefore, the content of the metal compound 12 in the catalyst 10 provided by the application is higher, and the catalytic efficiency is higher.
In one embodiment, the loading of the metal compound 12 per unit area of the carbon material 11 is greater than or equal to 10wt%. Alternatively, the loading amount of the metal compound 12 per unit area of the carbon material 11 may be 10wt%, 12wt%, 15wt%, 20wt%, 30wt%, 50wt%, 100wt%, or the like.
In the catalyst provided by the invention, the content of the metal compound 12 is more (obviously more than the catalyst amount in the prior art), because the metal compound 12 grows on the carbon material 11 in situ, compared with a physical mixing mode, the bulk density of the grown metal compound 12 on the carbon material 11 is higher, and the metal compound 12 is more densely attached, so that the content of the metal compound 12 in unit area is higher (can exceed 10 wt%); and the carbon material 11 has a large number of active sites, so that the adhesion strength of the metal compound 12 is higher, the metal compound 12 is not easy to fall off in mixing or transportation, and the load of the metal compound 12 is not easy to be reduced.
Satisfying the loading amount of the metal compound 12 per unit area of the carbon material 11 within the above-described range can ensure that the catalyst 10 as a whole is homogeneous, the distribution of the metal compound 12 on the carbon material 11 is uniform, and the content of the metal compound 12 is moderate. When the loading amount of the metal compound 12 per unit area of the carbon material 11 is less than the above range, the metal compound 12 in the catalyst 10 is small, and it is difficult to perform an effective catalytic function.
In one embodiment, the present invention provides a composite lithium supplementing material, please refer to fig. 4, comprising: a lithium-rich material 20 and the catalyst 10 in the above embodiments, the catalyst 10 being combined with the lithium-rich material 20.
In particular, the lithium-rich material 20 may be used for lithium supplementation, and the lithium-rich material 20 may be in the form of particles, including spheres or spheroids. The lithium-rich material 20 may be primary particles or secondary particles formed by aggregation of primary particles. Lithium (Li) in the lithium-rich material 20 can be released and migrate to the battery negative electrode during the first charge process to counteract irreversible lithium loss caused by formation of the SEI film, thereby improving the total capacity and energy density of the battery.
In some embodiments, the lithium-rich material comprises a higher decomposition voltage lithium-supplementing material, including predominantly lithium-supplementing materials with a delithiation potential above 4V, such as Li 2C2O4 (delithiation potential 4.7V), li 2 O (delithiation potential 4.5V), li 2O2 (delithiation potential 4.3V), liOH (delithiation potential 4.8V), li 4SiO4 (delithiation potential 4.5V), li 3PO4 (delithiation potential exceeding 4V), li 2CO3 (delithiation potential 4.7V), li 5FeO4 (delithiation potential 4V). The lithium-rich materials have higher capacity, but the lithium-rich materials require higher charging voltage for lithium removal, so that the technical problem of high platform voltage exists, meanwhile, the higher voltage also causes the lithium-supplementing material to generate oxygen when the lithium ion battery is charged and discharged for the first time, and the generated oxygen is further oxidized to cause the oxidative decomposition of electrolyte, so that the safety of the lithium ion battery is reduced and the performance is reduced. The lithium supplementing materials with higher decomposition voltages are difficult to compound with conventional cathode materials (such as lithium iron phosphate with a lithium removal potential of about 3.5V), so that the wide application of the lithium supplementing materials is limited. Therefore, the invention can effectively reduce the decomposition voltage of the lithium-rich material by utilizing the catalysis of the metal compound and further strengthening the catalysis of the metal compound through the conductivity of the carbon material, thereby improving the utilization rate of the lithium-rich material with higher decomposition voltage; in addition, the carbon material combined on the lithium-rich material strengthens the connection strength of the lithium-rich material and the catalyst through the combination effect of the active sites on the surface of the carbon material, so that the catalyst is not easy to fall off from the lithium-rich material, the stability of the catalyst is high, and the catalysis effect on the lithium-rich material is stronger.
Optionally, the lithium supplementing material may further include a binary lithium supplementing agent and/or a ternary lithium supplementing agent. It is understood that the above catalyst can be combined with the lithium-supplementing agents to reduce the decomposition voltage of the lithium-supplementing agents or to improve the conductivity of the lithium-supplementing agents. The corresponding chemical formula of the binary lithium supplementing agent is Li x2My2, wherein M is at least one element in S, P, N, F, B, O, se, te, x2 is more than or equal to 1 and less than or equal to 5, and y2 is more than or equal to 0. The dual lithium supplement includes, but is not limited to, at least one of Li 3N、Li2S、LiF、Li3P、Li2Se、Li2 O.
Optionally, the ternary lithium supplementing agent has a corresponding chemical formula of Li aMbOc, wherein M is at least one element of Fe, ni, mn, cu, zn, co, cr, zr, sb, ti, V, mo, sn and the like, a is more than or equal to 1 and less than or equal to 8, b is more than 0 and less than or equal to 0, and c is more than 0 and less than 7. In particular embodiments, the lithium-rich material may be at least one of Li5FeO4、Li6MnO4、Li6CoO4、Li6ZnO4、Li2NiO2、Li2CuO2、Li2CoO2、Li2MnO2、Li2Ni0.5Mn1.5O4、Li2NidCu(1-d)O2(0＜d＜1), etc.
The above-mentioned lithium-rich material 20 may be undoped or doped-modified, or may be surface-coated, pre-lithiated, or the like. In the case of using the lithium-rich material 20 as the positive electrode active material in the embodiment of the present invention, the lithium-rich material 20 may be a combination of the above-listed lithium-rich material 20 and a conventional positive electrode material such as lithium iron phosphate or ternary positive electrode material.
Alternatively, the catalyst 10 in combination with the lithium-rich material 20 may be: the catalyst 10 is bonded to the outer surface of the lithium-rich material 20, e.g., the catalyst 10 completely encapsulates or semi-encapsulates the lithium-rich material 20; or the lithium-rich material 20 is bonded to the outer surface of the catalyst 10, for example, the lithium-rich material 20 completely encapsulates or semi-encapsulates the catalyst 10.
The catalyst 10 provided by the embodiment is combined with the lithium-rich material 20 to obtain the composite lithium-supplementing material, so that the catalyst has the following effects: 1) The lithium-rich material 20 can be provided with a high-loading catalyst 10, and because the content of the metal compound 12 in the catalyst 10 is higher based on the structure of the catalyst 10, the composite lithium-rich material provided by the invention is provided with more catalysts 10 in the lithium-rich material under the same volume, and the catalytic action of the catalyst 10 on the lithium-rich material 20 is enhanced, so that the decomposition voltage of the lithium-rich material 20 is reduced more obviously; 2) The combination of the lithium-rich material 20 and the catalyst 10 is tighter, and since the carbon material 11 in the catalyst 10 can provide a larger specific surface area, the carbon material 11 has more active sites, the lithium-rich material 20, the carbon material 11 and the metal compound 12 are firmly combined together by using intermolecular forces, the metal compound 12 is not easy to fall off from the carbon material 11, and the whole catalyst 10 is not easy to fall off from the lithium-rich material 20, so that the catalytic effect of the catalyst 10 is enhanced in the process of catalyzing the lithium-rich material 20 by the catalyst 10, and the decomposition voltage of the lithium-rich material 20 can be further reduced.
In one embodiment, referring to fig. 2, the heteroatoms of the non-carbon element include nonmetallic heteroatoms, which are chemically bonded to carbon atoms of the carbon material 11.
Specifically, the nonmetallic heteroatom includes at least one of an N atom, a P atom, an S atom, and a B atom. Furthermore, nonmetallic heteroatoms are capable of forming single-, double-or triple-bond chemical bonds with carbon atoms.
The purpose of adopting nonmetallic heteroatom doping is to improve the conductivity of the carbon material 11, and can make the carbon material 11 catalytic, so as to improve the comprehensive performance of the carbon material 11. In addition, the non-metal hetero atoms are adopted to dope the carbon material 11, so that the surface structure defects and the surface area of the carbon material 11 can be increased, more active sites are exposed, and the subsequent growth of the metal compound 12 is facilitated.
In one embodiment, referring to fig. 2, the heteroatoms of the non-carbon element further include metal heteroatoms, which are covalently linked to the non-metal heteroatoms.
Specifically, the metal heteroatom includes at least one of Mo atom, co atom, mn atom. Furthermore, the metal heteroatom is capable of forming a covalent bond with the nonmetallic heteroatom.
The purpose of doping modification with metal heteroatoms is to increase the conductivity of the carbon material 11 while increasing the stability of the carbon material 11 in the ORR reaction (redox reaction) and providing more active sites; the catalytic lithium-rich material decomposition also involves valence changes, and belongs to the category of redox reactions, so that metal heteroatoms are beneficial to the decomposition of the lithium-rich material; in addition, more active sites are also more beneficial to the growth of the late catalyst 10.
In one embodiment, the carbon material 11 has active sites that include carbon surface defects and/or functional groups to which the metal compound 12 is bound.
Specifically, on the basis of the above embodiment, the metal oxide precursor is first bound to the active site of the carbon material 11, and then reacts in situ on the active site to form the metal compound 12. The active sites include carbon surface defects and/or functional groups, wherein the carbon surface defects are from heteroatom doping, i.e., defects in chemical bonds between portions of the carbon atoms after doping, and defects in metal heteroatoms; the functional groups come from the carbon material 11 itself, either attached or post-treated.
For example, the carbon material 11 may be provided with a part of functional groups, specifically oxygen-containing functional groups, such as graphene oxide. Or the doped carbon material 11 is subjected to surface functionalization treatment so that the surface of the carbon material 11 can have rich functional groups. In a specific embodiment, the doped carbon material 11 may be washed in an acid solution to increase the functional groups and active sites on the surface thereof. Then, the metal oxide precursor is again supported on the treated carbon material 11.
Optionally, the functional group is a carboxyl group, which has an advantage of facilitating adsorption and loading of the metal compound 12 on the carbon material 11, thereby increasing the loading of the catalyst 10.
By subjecting the carbon material 11 to the surface functionalization treatment, the number of surface functional groups and adsorption sites of the metal compound 12 can be increased, thereby increasing the loading amount of the metal compound 12.
In one embodiment, the carbon material 11 has a three-dimensional network structure, and the metal compound 12 is bonded to the carbon skeleton of the carbon material 11 of the three-dimensional network structure.
Specifically, the carbon material 11 may be carbon nanotubes or carbon fibers, and a plurality of carbon nanotubes or carbon fibers are interwoven to form a three-dimensional network structure, so that each carbon nanotube or carbon fiber forms the carbon skeleton. Then, at least one carbon nanotube or carbon fiber may have a metal compound 12 bonded thereto; it will be appreciated that the metal compound 12 and carbon nanotubes or carbon fibers form a structure similar to grape and grape vine.
The carbon material 11 with the three-dimensional network three-dimensional structure has larger specific surface area, and on one hand, the carbon material is easier to modify, so that doped hetero atoms can be more uniformly distributed on each carbon skeleton; on the other hand, the surface of the carbon material 11 can form more active sites, thereby increasing the loading amount of the metal compound 12, and the connection strength therebetween.
In one embodiment, the carbon material 11 is bonded to a portion or all of the outer surface of the metal compound 12, such that the carbon material 11 provides a half-or full-coating of the metal compound 12.
Specifically, based on the above embodiment, the carbon material 11 may be carbon black or ketjen black, and most of the carbon material 11 is in powder form, and may be mixed with the metal oxide precursor, so that the carbon material 11 is coated on the outer surface of the precursor. Of course, the specific style of the cladding is not limited, and may be a half-cladding or full-cladding structure.
In one embodiment, the mass ratio of the carbon material 11 to the metal compound 12 is 100: (10-150). Alternatively, the mass ratio of the carbon material 11 to the metal compound 12 may be 100:10、100:20、100:30、100:40、100:50、100:60、100:70、100:80、100:90、100:100、100:110、100:120、100:130、100:140、100:150., and the mass ratio of the carbon material 11 to the metal compound 12 may be 100: (10-120), 100: (10-100), 100: (10-80).
Satisfying the mass ratio of the carbon material 11 and the metal compound 12 within the above range can ensure that the catalyst 10 has a high decomposition voltage catalytic ability and a suitable conductivity. When the ratio of the carbon material 11 is larger than the above range, the carbon material 11 is excessive, and although the electrical conductivity of the catalyst 10 is enhanced, the ability of the catalyst 10 to reduce the catalytic decomposition voltage becomes weak, and when the catalyst 10 and the lithium-rich material are mixed, the reduction in the decomposition voltage of the lithium-rich material is limited. When the mass ratio of the metal compound 12 is larger than the above range, the electrical conductivity of the catalyst 10 becomes poor, resulting in deterioration of the electrical conductivity of the lithium-rich material.
In one embodiment, the doping amount of the hetero atoms on the carbon material 11 is 0.1wt% to 5wt%. Alternatively, the doping amount of the hetero atom on the carbon material 11 may be 0.1wt%, 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, 5wt%.
The doping amount of the hetero atoms on the carbon material 11 is within the above range, and structural stability of the carbon material 11 can be ensured while ensuring improvement of conductivity and catalytic activity of the carbon material 11. When the doping amount of the hetero atoms on the carbon material 11 is smaller than the above range, the conductivity of the carbon material 11 tends to be an undoped state, and the content of the grown bond metal compound 12 on the carbon material 11 is small, resulting in weaker catalytic activity. When the doping amount of the hetero atoms on the carbon material 11 is larger than the above range, chemical bonds of the carbon atoms are mainly connected to the hetero atoms, resulting in weakening of the connection strength between the carbon atoms of the carbon material 11 and deterioration of the structural stability of the carbon material 11.
In one embodiment, the number of catalysts 10 is plural, and the plural catalysts 10 are distributed on the outer surface of the lithium-rich material 20.
Specifically, the catalyst 10 and the lithium-rich material 20 may each be in the form of a sphere or a particle like sphere, and the outer surface of the lithium-rich material 20 may be distributed with a plurality of catalysts 10. The plurality of catalysts 10 form a discontinuous, punctiform distribution on the outer surface of the lithium-rich material 20. The catalyst 10 may be independently distributed on the outer surface of the lithium-rich material 20 to form a discontinuous structure, and the particles of the catalyst 10 are independent of each other.
It will be appreciated that, in addition to the above embodiment, the structure of the catalyst 10 may be such that the carbon material 11 is coated with the metal compound 12, so the resulting catalyst 10 may also be in the form of particles.
In one embodiment, the catalyst 10 is coated on the outer surface of the lithium-rich material 20 and forms a coating.
Specifically, the composite lithium supplementing material comprises an inner core and a coating layer, wherein the coating layer is coated on the outer surface of the inner core; wherein the inner core comprises a lithium-rich material 20 and the coating comprises the catalyst 10. The mode that the catalyst 10 coats the lithium-rich material 20 is adopted, so that the catalyst 10 is used as a packaging coating layer, and on one hand, the catalyst 10 can exert the maximum catalytic effect; on the other hand, the coating layer can reduce the erosion of external water vapor to the lithium-rich material 20 and reduce the gas production of the material in the core, so as to improve the electrochemical performance of the composite lithium-supplementing material.
In one embodiment, the catalyst 10 is a three-dimensional network structure and is coated on the outer surface of the lithium-rich material 20.
Specifically, in the above embodiment, the outer surface of the lithium-rich material 20 is covered with a fishing net-shaped covering layer, and the covering layer is composed of the carbon material 11 having a three-dimensional network structure and the metal compound 12 grown on the carbon material 11.
In one embodiment, the D50 particle size of the lithium-rich material 20 is 100nm to 10 μm. Alternatively, the D50 particle size of the lithium-rich material 20 may be 100nm, 500nm, 800nm, 1 μm, 2 μm, 3 μm, 5 μm, 7 μm, 8 μm, 9 μm, 10 μm. Alternatively, the D50 particle size of the lithium-rich material 20 is 800nm to 10 μm, 1 μm to 10 μm, 2 μm to 10 μm.
Meeting the particle size of the lithium-rich material 20 within the above range can ensure the catalytic effect of the catalyst 10 on the lithium-rich material 20, improve the release efficiency of lithium ions, and reduce the difficulty of preparing the material. When the particle diameter of the lithium-rich material 20 is smaller than the above range, the difficulty in preparing the lithium-rich material 20 increases, and the lithium-rich material 20 is severely agglomerated and is not easily dispersed to be combined with the catalyst 10. When the particle diameter of the lithium-rich material 20 is greater than the above range, the catalytic effect of the catalyst 10 on the lithium-rich material 20 is reduced, and the release path of lithium ions is longer, affecting the delithiation efficiency of the material.
In one embodiment, the mass ratio of the catalyst 10 in the composite lithium supplementing material is 5-40 wt%. Alternatively, the mass ratio of the catalyst 10 in the composite lithium supplementing material is 5wt%, 10wt%, 12wt%, 14wt%, 16wt%, 18wt%, 20wt%, 22wt%, 24wt%, 26wt%, 28wt%, 30wt%, 35wt%, 40wt%. Optionally, the mass ratio of the catalyst 10 in the composite lithium supplementing material is 10-40 wt%, 10-35 wt% and 10-30 wt%.
The mass ratio of the catalyst 10 in the composite lithium supplementing material is within the above range, so that the catalytic effect of the catalyst 10 on the lithium rich material 20 can be ensured, and the lithium ion capacity of the composite lithium supplementing material can be satisfied. When the mass ratio of the catalyst 10 in the composite lithium supplementing material is smaller than the above range, too small a catalyst 10 results in poor catalytic effect, and the lithium releasing voltage of the lithium rich material 20 is limited to drop. When the mass ratio of the catalyst 10 in the composite lithium supplementing material is greater than the above range, the catalyst 10 is excessive, and the lithium capacity is reduced because the catalyst 10 does not contribute lithium ions.
In one embodiment, the present invention further provides a method for preparing a composite lithium-supplementing material, please refer to fig. 5, which includes:
And step S10, mixing and reacting the carbon material and the heteroatom raw material of the non-carbon element to obtain the carbon material doped with the heteroatom of the non-carbon element.
And step S20, mixing and reacting the carbon material and the metal oxide precursor to obtain the catalyst, and converting the metal oxide precursor into a metal compound and growing on the carbon material.
And step S30, mixing and calcining the catalyst and the lithium-rich material together to obtain the composite lithium-supplementing material.
Optionally, in step S10, the type of the carbon material may be referred to as provided in the above embodiment, which is not described herein. Heteroatom sources include nonmetallic heteroatom sources and/or metallic heteroatom sources.
Optionally, in step S10, the process method of mixing the carbon material and the heteroatom raw material of the non-carbon element includes, but is not limited to, physical grinding mixing, chemical vapor deposition, arc discharge, laser evaporation, etc.
Optionally, in step S20, the metal oxide precursor includes carbonate, sulfate, phosphate, nitrate, organic salt, hydroxide, and the like, and is not particularly limited.
Optionally, in step S20, the process method of the mixing reaction of the carbon material and the metal oxide precursor includes, but is not limited to, physical grinding mixing, high temperature calcination, chemical vapor deposition, atomic deposition, or the like.
Alternatively, the catalyst may be coated on the outer surface of the lithium-rich material to form a coating layer. The type of the lithium-rich material may refer to the above embodiments, and will not be described herein.
Optionally, the calcination environment in the above steps is under an inert atmosphere, and the inert atmosphere includes at least one of nitrogen, argon, helium and the like.
In one embodiment, referring to fig. 6, the preparation method of the composite lithium supplementing material may further specifically include the following steps:
And S11, mixing and reacting the carbon material and a nonmetallic heteroatom raw material to obtain the nonmetallic heteroatom doped carbon material.
And step S12, mixing and reacting the carbon material and the metal heteroatom raw material to obtain the nonmetal heteroatom and metal heteroatom co-doped carbon material, wherein the metal heteroatom and the nonmetal heteroatom are connected through a covalent bond.
And step S21, performing surface functionalization treatment on the carbon material.
And S22, mixing and reacting the carbon material subjected to surface functionalization treatment with a metal oxide precursor to obtain the catalyst.
And S31, mixing and calcining the catalyst and the lithium-rich material together to obtain the composite lithium-supplementing material.
Optionally, in step S11, the nonmetallic heteroatom raw material may be urea, ammonia, dopamine hydrochloride, or the like.
Optionally, in step S11, the carbon material and the nonmetallic heteroatom raw material are mixed and reacted, specifically including: mixing a carbon material and a nonmetallic heteroatom raw material to form a solution, drying to obtain a solid mixture, and grinding the solid mixture to obtain the nonmetallic heteroatom doped carbon material.
Alternatively, in step S12, the metal heteroatom raw material may be an organic metal salt, such as ammonium molybdate, ammonium cobaltate, or the like.
Optionally, in step S12, the carbon material and the metal heteroatom raw material are mixed and reacted, specifically including: mixing a non-metal heteroatom doped carbon material with a metal heteroatom raw material in a solvent, reacting at a high temperature, cooling, drying, and calcining at a high temperature to obtain the non-metal heteroatom and metal heteroatom co-doped carbon material.
Optionally, in step S12, the carbon material and the metal heteroatom raw material may be reacted at a high temperature for 6h to 10h, and the reaction temperature may be 100 ℃ to 200 ℃.
Optionally, in step S12, the product after the reaction is calcined at a high temperature for 8-15 hours, and the calcining temperature may be 600-900 ℃.
Optionally, in step S21, the surface functionalization treatment is performed on the carbon material, specifically including: adding the doped carbon material into the treatment liquid, boiling, stirring, filtering and drying to obtain the heteroatom doped carbon material with the surface functionalized treatment.
Alternatively, in step S21, the treatment liquid may be an acid or alkali solution, including but not limited to nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid, oxalic acid, sodium hydroxide, lithium hydroxide, and the like.
Optionally, in step S22, the surface functionalized carbon material and the metal oxide precursor are mixed and reacted, specifically including: adding a carbon material and a metal oxide precursor into a solvent together, uniformly mixing, transferring to a reaction kettle, reacting at a high temperature, cooling, drying, and calcining at a high temperature to convert the metal oxide precursor into a metal compound, thereby obtaining the catalyst.
Optionally, in step S22, the carbon material and the metal oxide precursor may be reacted at a high temperature for 8 to 15 hours, and the reaction temperature may be 80 to 200 ℃.
Optionally, in step S22, the product after the reaction is calcined at a high temperature for 3 to 10 hours, and the calcination temperature may be 600 to 900 ℃.
According to the preparation method of the catalyst, the heteroatom is doped in the carbon material, and the metal oxide precursor is utilized to convert the metal compound in situ, so that the catalyst can have conductivity and catalytic capability at the same time; and through heteroatom doping, the carbon material in the catalyst has higher conductivity and catalytic activity, and the doped carbon material can play a synergistic effect with a metal compound, so that the comprehensive performance of the catalyst is improved.
In addition, the application also increases the surface functional groups and active sites of the carbon material by acid washing the carbon material, and then grows the metal compound on the surface of the conductive carbon material, thereby increasing the intermolecular acting force between the metal compound and the carbon material. Then sintering the catalyst and the lithium-rich material together, and coating the catalyst on the surface of the lithium-rich material, wherein the catalyst contains conductive carbon material, so that no additional carbon material is needed. Thereby firmly combining the metal compound, the carbon material and the lithium-rich material together, and reducing the lithium removal potential of the lithium-rich material.
In one embodiment, the invention also provides a positive electrode material, which comprises a positive electrode active material and a lithium supplementing material. The lithium supplementing material includes the composite lithium supplementing material provided in the above embodiment mode. Alternatively, the positive electrode active material may be a phosphate positive electrode active material or a ternary positive electrode active material, and in a specific embodiment, the positive electrode active material includes one or more of lithium cobaltate, lithium manganate, lithium iron phosphate, lithium manganese iron phosphate, lithium vanadium phosphate, lithium vanadyl phosphate, lithium vanadium fluorophosphate, lithium titanate, lithium nickel cobalt manganate, and lithium nickel cobalt aluminate.
In one embodiment, the content of the composite lithium supplementing material in the positive electrode material can be controlled to be 1-6% of the mass of the positive electrode active material. The ratio can exactly compensate the loss of active lithium in the first charging process of the battery. If the addition amount of the composite lithium supplementing material in the positive electrode material is too low, the lost active lithium in the positive electrode active material cannot be fully supplemented, which is unfavorable for improving the energy density, capacity retention rate and the like of the battery. If the addition amount of the composite lithium supplementing material in the positive electrode active material is too high, the original reversible capacity is occupied, and the cost is increased. In some embodiments, the mass percentage of the composite lithium-supplementing material in the positive electrode material may be 1%, 2%, 4%, 6%, etc.
In one embodiment, the invention also provides a positive electrode sheet, which comprises a current collector and an active material layer arranged on the current collector, wherein the active material layer comprises the composite lithium supplementing material in any one of the embodiments. Or the active material layer comprises the composite lithium supplementing material obtained by the preparation method of the composite lithium supplementing material in the embodiment.
In one embodiment, the positive electrode plate comprises a positive electrode current collector, the positive electrode current collector is provided with a positive electrode active layer, the positive electrode active layer comprises positive electrode active materials, composite lithium supplementing materials, conductive agents, binders and the like, the materials are not particularly limited, and proper materials can be selected according to actual application requirements. The positive electrode current collector includes, but is not limited to, any one of copper foil and aluminum foil. The conductive agent comprises one or more of graphite, carbon black, acetylene black, graphene, carbon fiber, C60 and carbon nano tube, and the content of the conductive agent in the positive electrode active layer is 3-5 wt%. The binder comprises one or more of polyvinylidene chloride, soluble polytetrafluoroethylene, styrene-butadiene rubber, hydroxypropyl methyl cellulose, carboxymethyl cellulose, polyvinyl alcohol, acrylonitrile copolymer, sodium alginate, chitosan and chitosan derivatives, and the content of the binder in the positive electrode active layer is 2-4wt%.
In one embodiment, the invention also provides a secondary battery, which comprises a negative electrode plate, a diaphragm and the positive electrode plate. The positive electrode plate comprises the composite positive electrode material.
The technical scheme of the invention is described in detail by specific examples.
Example 1
The embodiment provides a catalyst and a composite lithium supplementing material.
The composite lithium supplementing material comprises a catalyst (MnO@CNT) and a lithium rich material (Li 2C2O4), wherein the catalyst is coated on the outer surface of the lithium rich material. Wherein, the CNT (carbon nanotube) is doped with N atoms and Mo atoms, the N atoms are connected with C atoms of the CNT through chemical bonds, and the N atoms are connected with Mo atoms through covalent bonds.
Wherein the doping amount of the N atoms and the Mo atoms on the CNT is 2wt%; the mass ratio of CNT to MnO is 100:66.7; the loading of MnO on the CNTs was 40wt%; the D50 particle size of the lithium-rich material is 3 mu m; the thickness of the coating layer is 100nm; the mass ratio of the catalyst when mixed with the lithium-rich material was 20wt%.
The preparation method of the composite catalyst and the composite lithium supplementing material comprises the following steps:
(1) 40ml of ethanol was added to 2.0g of CNT and 6.0g of urea to form a mixed solution, and then the sample was ground at 600rpm for 4 hours to obtain N-atom doped CNT.
(2) 2.0G of ammonium molybdate and 2.0g N atom doped CNT are dissolved together in 30ml of deionized water, and after being stirred uniformly, transferred into a reaction kettle and maintained at 160 ℃ for 8 hours. Cooling to room temperature, taking out, washing with deionized water, drying, and heating at 800 ℃ for 10 hours in an inert atmosphere in a tube furnace to obtain the Mo atom (modified) N atom doped CNT.
(3) Dispersing 2.0g of doped CNT into 40ml of 60% concentrated nitric acid, magnetically stirring and boiling for 2 hours, filtering, washing and drying to obtain the doped CNT with surface functionalization treatment.
(4) Adding 1g of the surface functionalized doped CNT and 10g of manganese acetate tetrahydrate into a mixed solution of 30ml of deionized water and 20ml of ethanol, uniformly mixing, transferring into a reaction kettle, maintaining at 120 ℃ for 12 hours, recovering to room temperature, washing with deionized water, and drying to obtain a catalyst precursor loaded on carbon.
(5) And placing the obtained CNT loaded with the catalyst precursor in a tube furnace, and maintaining the temperature at 600 ℃ for 5 hours under an inert atmosphere to obtain the MnO@CNT.
(6) Then, 0.15g of MnO@CNT obtained was mixed with 0.85g of Li 2C2O4 by means of grinding and a refiner, and then maintained at 400℃for 5 hours under an inert atmosphere, to obtain a composite lithium supplementing material.
Example 2
The embodiment provides a catalyst and a composite lithium supplementing material.
The composite lithium supplementing material comprises a catalyst (MnO@CNT) and a lithium rich material (Li 2C2O4), wherein the catalyst is coated on the outer surface of the lithium rich material. Wherein, only N atoms are doped in the CNTs (carbon nanotubes), and the N atoms are connected with C atoms of the CNTs through chemical bonds.
Wherein the doping amount of the N atoms on the CNT is 0.8wt%; the mass ratio of CNT to MnO is 100:51.5, mnO loading on CNT was 34wt%; the D50 particle size of the lithium-rich material is 3 mu m; the thickness of the coating layer is 180nm; the mass ratio of the catalyst when mixed with the lithium-rich material was 20wt%.
The preparation method of this example 2 differs from that of example 1 in that: the CNT is doped with only N element and not with metal element.
Example 3
The embodiment provides a catalyst and a composite lithium supplementing material.
The composite lithium supplementing material comprises a catalyst (MnO@CNT) and a lithium rich material (Li 2C2O4), wherein the catalyst is coated on the outer surface of the lithium rich material. Wherein Mo atoms are doped in the CNT (carbon nanotube), and the Mo atoms are connected with C atoms of the CNT through chemical bonds.
Wherein the doping amount of Mo atoms on the CNT is 1.2wt%; the mass ratio of CNT to MnO is 100:42.9, mnO loading on the CNTs of 30wt%; the D50 particle size of the lithium-rich material is 3 mu m; the thickness of the coating layer is 200nm; the mass ratio of the catalyst when mixed with the lithium-rich material was 20wt%.
The preparation method of this example 3 differs from that of example 1 in that: the CNT is doped with Mo only and not with N.
Example 4
The embodiment provides a catalyst and a composite lithium supplementing material.
The composite lithium supplementing material comprises a catalyst (MnO@CNT) and a lithium rich material (Li 2C2O4), wherein the catalyst is coated on the outer surface of the lithium rich material. Wherein, the CNT (carbon nanotube) is doped with N atoms and Mo atoms, the N atoms are connected with C atoms of the CNT through chemical bonds, and the N atoms are connected with Mo atoms through covalent bonds.
Wherein the doping amount of the N atoms and the Mo atoms on the CNT is 1.3wt%; the mass ratio of CNT to MnO is 100:25, mnO loading on the CNT was 20wt%; the D50 particle size of the lithium-rich material is 3 mu m; the thickness of the coating layer is 200nm; the mass ratio of the catalyst when mixed with the lithium-rich material was 20wt%.
The preparation method of this example 4 differs from that of example 1 in that: the CNT was not acid washed.
Example 5
The embodiment provides a catalyst and a composite lithium supplementing material.
The composite lithium supplementing material comprises a catalyst (MnO@CNT) and a lithium rich material (Li 2C2O4), wherein the catalyst is coated on the outer surface of the lithium rich material. Wherein, the CNT (carbon nanotube) is doped with N atoms and Mo atoms, the N atoms are connected with C atoms of the CNT through chemical bonds, and the N atoms are connected with Mo atoms through covalent bonds.
Wherein the doping amount of the N atoms and the Mo atoms on the CNT is 2wt%; the mass ratio of CNT to NiO is 100:47.1, the loading of NiO on CNT was 32wt%; the D50 particle size of the lithium-rich material is 3 mu m; the thickness of the coating layer is 160nm; the mass ratio of the catalyst when mixed with the lithium-rich material was 20wt%.
The preparation method of this example 5 differs from that of example 1 in that: the metal compound in the catalyst is changed from MnO to NiO.
Example 6
The embodiment provides a catalyst and a composite lithium supplementing material.
The composite lithium supplementing material comprises a catalyst (MnO@CNT) and a lithium rich material (Li 2CO3), wherein the catalyst is coated on the outer surface of the lithium rich material. Wherein, the CNT (carbon nanotube) is doped with N atoms and Mo atoms, the N atoms are connected with C atoms of the CNT through chemical bonds, and the N atoms are connected with Mo atoms through covalent bonds.
Wherein the doping amount of the N atoms and the Mo atoms on the CNT is 2wt%; the mass ratio of CNT to MnO is 100:66.7; the loading of MnO on the CNTs was 40wt%; the D50 particle size of the lithium-rich material is 5 mu m; the thickness of the coating layer is 140nm; the mass ratio of the catalyst when mixed with the lithium-rich material was 20wt%.
The preparation method of this example 6 differs from that of example 1 in that: and replacing lithium oxalate as a lithium-rich material with lithium carbonate as a lithium-rich material.
Comparative example 1
This comparative example provides a lithium-rich material (Li 2C2O4).
Comparative example 2
This comparative example provides a lithium-rich material (Li 2CO3).
Comparative example 3
This comparative example provides a composite lithium-supplementing material comprising MnO and Li 2C2O4, mnO and Li 2C2O4 simply mixed.
Comparative example 4
This comparative example provides a composite lithium-supplementing material comprising CNT and Li 2C2O4, CNT and Li 2C2O4 simply mixed.
Comparative example 5
This comparative example provides a composite lithium-supplementing material comprising MnO, CNT and Li 2C2O4, with simple mixing of MnO, CNT and Li 2C2O4.
The composite lithium-supplementing materials provided in examples 1 to 6 and the composite lithium-supplementing materials provided in comparative examples 1 to 5 were assembled into a positive electrode sheet and a lithium ion battery, respectively, according to the following methods:
positive pole piece: the composite lithium supplementing material, SP and PVDF are mixed according to the following ratio of 90:4: mixing the homogenized positive electrode slurry according to the mass ratio of 6, coating the positive electrode slurry on the surface of an aluminum foil, vacuum drying overnight at 110 ℃, and rolling to obtain a positive electrode plate;
Negative pole piece: a lithium sheet;
Electrolyte solution: mixing ethylene carbonate and ethylmethyl carbonate in a volume ratio of 3:7, and adding LiPF 6 to form an electrolyte, wherein the concentration of LiPF 6 is 1mol/L;
A diaphragm: a polypropylene microporous separator;
And (3) assembling a lithium ion battery: and assembling the button type lithium ion full battery in an inert atmosphere glove box according to the assembling sequence of the negative electrode plate, the diaphragm, the electrolyte and the positive electrode plate.
Each lithium ion battery assembled in the above lithium ion battery example was subjected to electrochemical performance test under the following conditions:
Charging at 0.1C with a cut-off voltage of 4.7V; constant voltage charging was performed at 4.7V. After the charging process was completed, the mixture was allowed to stand for 10 minutes to discharge at a rate of 0.1C, and the cut-off voltage was 2.5V.
Electron conductivity test: the resistivity of the positive electrode lithium-supplementing material in each example and comparative example is obtained through test calculation by a four-probe method, and the electronic conductivity is obtained by taking the reciprocal of the resistivity.
The test results of the above composite lithium supplementing materials and lithium batteries are shown in the following table 1:
TABLE 1 test results for examples and comparative examples
As can be seen from the test results of example 1 and comparative example 1 in table 1, the composite lithium-compensating material prepared in example 1 has a much higher initial charge specific capacity and an electron conductivity than those of the lithium oxalate common in comparative example 1, and the composite lithium-compensating material in example 1 has a lower charge voltage plateau than those of the lithium oxalate common in comparative example 1. According to the scheme provided by the invention, the electronic conductivity of the material can be improved on the basis of reducing the charging voltage platform of the lithium-rich material, so that the capacity of the material can be fully released, and the matching degree of battery use is improved. Therefore, the electrochemical performance of the composite lithium supplementing material provided by the invention is far higher than that of the existing common lithium-rich material.
From the test results of examples 1 to 3 in table 1, it can be seen that the performance of the composite lithium supplementing material can be further improved by doping non-carbon heteroatoms (metal heteroatoms or non-metal heteroatoms) in the carbon material. In example 2, a metal element (Mo atom) was not doped, and in example 3, a non-metal element (N atom) was not doped, so that the active sites on the carbon materials of example 2 and example 3 were smaller than those of example 1, and the carbon materials of example 2 were weaker in the ORR reaction (redox reaction) than those of example 1, so that the catalysts of example 2 and example 3 were smaller in metal oxide loading than those of example 1 on the one hand, and were also weaker in catalytic redox reaction than those of example 1.
From the test results of example 1 and example 4 in table 1, it can be seen that the acid washing has an effect on the performance of the catalyst. Because acid washing can increase the surface functional groups and active sites of the carbon material, then the metal compound grows on the surface of the carbon material, and intermolecular acting force between the metal compound and the carbon material is increased. Therefore, the catalyst has stronger catalysis effect, the catalyst loading capacity in the obtained composite lithium supplementing material is higher, the corresponding first-time charging specific capacity is higher, the voltage platform is lower, and the electronic conductivity is also higher.
From the test results of example 1, example 5 and example 6 in table 1, it can be seen that different metal oxides as catalysts and different lithium-rich materials are suitable for this improvement. Comparing the example 1 with the example 5, it can be seen that different metal compounds can be used as catalysts to reduce the lithium removal potential of the lithium-rich material, so as to increase the initial charge specific capacity and the electron conductivity; from the lithium ion battery performance of comparative example 1 and example 6, it can be seen that the method is applicable to different lithium-rich material systems.
From the test results of examples 1 and 1, and examples 6 and 2 in table 1, it can be seen that the performance is significantly improved after doping the high loading catalyst grown on the carbon surface, regardless of whether Li 2C2O4 or Li 2CO3 is used as the lithium-rich material, demonstrating the feasibility of elemental doping and acid washing of CNTs and growing metal compounds on their surfaces as catalysts.
The lithium ion battery performance of comparative examples 1,3, 4 and 5, it can be seen that if the metal compound catalyst, the conductive carbon material and the lithium-rich material are mechanically mixed together only, the combination between the three is not strong enough, so that the performance is not better than the catalyst grown on the surface of carbon even though the components are uniformly mixed, thereby explaining the necessity of a method of doping modifying the carbon material and growing the catalyst on the surface thereof.
In the description of the embodiments of the present invention, it should be noted that, the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," and the like refer to the orientation or positional relationship described based on the drawings, which are merely for convenience of description and simplification of the description, and do not indicate or imply that the apparatus or element in question must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention.
The above disclosure is only a preferred embodiment of the present invention, and it should be understood that the scope of the invention is not limited thereto, but all or part of the procedures for implementing the above embodiments can be modified by one skilled in the art according to the scope of the appended claims.
Claims (10)
1. A catalyst, comprising:
a carbon material doped with heteroatoms of non-carbon elements; and
A metal compound grown on the carbon material.
2. The catalyst of claim 1, wherein the loading of the metal compound on the carbon material is greater than or equal to 10wt%.
3. A composite lithium supplementing material, comprising:
A lithium-rich material; and
The catalyst of claim 1 or 2, in combination with the lithium-rich material.
4. The composite lithium-compensating material of claim 3 wherein the heteroatom of the non-carbon element comprises a nonmetallic heteroatom that is chemically bonded to a carbon atom of the carbon material.
5. The composite lithium-compensating material of claim 4 wherein the heteroatom of the non-carbon element further comprises a metal heteroatom, the metal heteroatom being covalently bonded to the non-metal heteroatom.
6. A composite lithium-supplementing material according to claim 3, wherein the surface of the carbon material has active sites comprising carbon surface defects and/or functional groups, the metal compound being bound to the active sites; and/or
The carbon material has a carbon skeleton with a three-dimensional network structure, and the metal compound is combined on the carbon skeleton;
the carbon material comprises at least one of carbon nano tube, carbon fiber, graphene, carbon black and ketjen black; and/or
The metal compound comprises at least one of metal oxide, metal carbide and metal sulfide; and/or
The mass ratio of the carbon material to the metal compound is 100: (10-150);
The doping amount of the heteroatom of the non-carbon element on the carbon material is 0.1-5 wt%.
7. The composite lithium-supplementing material according to claim 3, wherein,
The catalyst is coated on the outer surface of the lithium-rich material and forms a coating layer; and/or the number of the groups of groups,
The D50 particle size of the lithium-rich material is 100 nm-10 mu m; and/or
The mass ratio of the catalyst in the composite lithium supplementing material is 5-40 wt%.
8. The preparation method of the composite lithium supplementing material is characterized by comprising the following steps of:
mixing and reacting a carbon material and a heteroatom raw material of a non-carbon element to obtain a carbon material doped with a heteroatom of the non-carbon element;
Mixing and reacting the carbon material and a metal compound precursor to convert the metal oxide precursor into a metal compound and grow the metal compound on the carbon material to obtain a catalyst;
And mixing and calcining the catalyst and the lithium-rich material together to obtain the composite lithium-supplementing material.
9. A positive electrode material, wherein the positive electrode material comprises an active material and a lithium supplementing material, the lithium supplementing material comprises the composite lithium supplementing material according to any one of claims 3 to 7, or comprises the composite lithium supplementing material obtained by the preparation method of the composite lithium supplementing material according to claim 8.
10. A secondary battery comprising a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode, the positive electrode comprising the positive electrode material according to claim 9.
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