CN115347254A - Composite positive electrode lithium supplement additive and preparation method and application thereof - Google Patents
Composite positive electrode lithium supplement additive and preparation method and application thereof Download PDFInfo
- Publication number
- CN115347254A CN115347254A CN202210793701.XA CN202210793701A CN115347254A CN 115347254 A CN115347254 A CN 115347254A CN 202210793701 A CN202210793701 A CN 202210793701A CN 115347254 A CN115347254 A CN 115347254A
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- China
- Prior art keywords
- positive electrode
- lithium
- lithium supplement
- electrode lithium
- additive
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Links
- 229910052744 lithium Inorganic materials 0.000 title claims abstract description 345
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 title claims abstract description 340
- 239000013589 supplement Substances 0.000 title claims abstract description 292
- 239000000654 additive Substances 0.000 title claims abstract description 151
- 230000000996 additive effect Effects 0.000 title claims abstract description 145
- 239000002131 composite material Substances 0.000 title claims abstract description 138
- 238000002360 preparation method Methods 0.000 title claims abstract description 33
- 239000000463 material Substances 0.000 claims abstract description 169
- 239000002245 particle Substances 0.000 claims abstract description 97
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 claims abstract description 93
- 229910052808 lithium carbonate Inorganic materials 0.000 claims abstract description 93
- 239000011247 coating layer Substances 0.000 claims abstract description 87
- 239000010410 layer Substances 0.000 claims description 68
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 32
- 239000003513 alkali Substances 0.000 claims description 32
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 30
- 238000006243 chemical reaction Methods 0.000 claims description 28
- 238000000034 method Methods 0.000 claims description 27
- 238000004806 packaging method and process Methods 0.000 claims description 24
- 229910052799 carbon Inorganic materials 0.000 claims description 22
- 230000008569 process Effects 0.000 claims description 18
- 239000001569 carbon dioxide Substances 0.000 claims description 16
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 16
- 230000002829 reductive effect Effects 0.000 claims description 12
- 239000002243 precursor Substances 0.000 claims description 9
- 239000002344 surface layer Substances 0.000 claims description 7
- 238000011065 in-situ storage Methods 0.000 claims description 6
- 229910052742 iron Inorganic materials 0.000 claims description 5
- 230000002441 reversible effect Effects 0.000 claims description 5
- 229910000314 transition metal oxide Inorganic materials 0.000 claims description 5
- 229910052710 silicon Inorganic materials 0.000 claims description 4
- 238000005245 sintering Methods 0.000 claims description 4
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 claims description 3
- 229910052718 tin Inorganic materials 0.000 claims description 3
- 229910052796 boron Inorganic materials 0.000 claims description 2
- 229910052802 copper Inorganic materials 0.000 claims description 2
- 229910052731 fluorine Inorganic materials 0.000 claims description 2
- 229910052757 nitrogen Inorganic materials 0.000 claims description 2
- 229910052760 oxygen Inorganic materials 0.000 claims description 2
- 229910052698 phosphorus Inorganic materials 0.000 claims description 2
- 229910052706 scandium Inorganic materials 0.000 claims description 2
- 229910052717 sulfur Inorganic materials 0.000 claims description 2
- 229910052727 yttrium Inorganic materials 0.000 claims description 2
- 239000003054 catalyst Substances 0.000 claims 1
- 230000000694 effects Effects 0.000 abstract description 26
- 238000003860 storage Methods 0.000 abstract description 10
- 238000004519 manufacturing process Methods 0.000 abstract description 6
- 239000011248 coating agent Substances 0.000 abstract description 5
- 238000000576 coating method Methods 0.000 abstract description 5
- 239000008187 granular material Substances 0.000 abstract description 5
- 230000002195 synergetic effect Effects 0.000 abstract 1
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 32
- 229910001416 lithium ion Inorganic materials 0.000 description 32
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 27
- 238000005538 encapsulation Methods 0.000 description 21
- 239000011532 electronic conductor Substances 0.000 description 14
- 239000010416 ion conductor Substances 0.000 description 14
- 230000000052 comparative effect Effects 0.000 description 12
- 239000010949 copper Substances 0.000 description 11
- 238000002156 mixing Methods 0.000 description 8
- IUVCFHHAEHNCFT-INIZCTEOSA-N 2-[(1s)-1-[4-amino-3-(3-fluoro-4-propan-2-yloxyphenyl)pyrazolo[3,4-d]pyrimidin-1-yl]ethyl]-6-fluoro-3-(3-fluorophenyl)chromen-4-one Chemical compound C1=C(F)C(OC(C)C)=CC=C1C(C1=C(N)N=CN=C11)=NN1[C@@H](C)C1=C(C=2C=C(F)C=CC=2)C(=O)C2=CC(F)=CC=C2O1 IUVCFHHAEHNCFT-INIZCTEOSA-N 0.000 description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 7
- 239000007789 gas Substances 0.000 description 7
- 230000001965 increasing effect Effects 0.000 description 7
- 239000000203 mixture Substances 0.000 description 7
- 239000007774 positive electrode material Substances 0.000 description 7
- 238000007599 discharging Methods 0.000 description 6
- 239000011261 inert gas Substances 0.000 description 6
- 229910052759 nickel Inorganic materials 0.000 description 6
- 239000000126 substance Substances 0.000 description 6
- 238000001354 calcination Methods 0.000 description 5
- 239000006258 conductive agent Substances 0.000 description 5
- 150000002500 ions Chemical class 0.000 description 5
- 230000002427 irreversible effect Effects 0.000 description 5
- 239000011164 primary particle Substances 0.000 description 5
- 239000010405 anode material Substances 0.000 description 4
- 239000010406 cathode material Substances 0.000 description 4
- 239000003795 chemical substances by application Substances 0.000 description 4
- 239000011258 core-shell material Substances 0.000 description 4
- 229910021389 graphene Inorganic materials 0.000 description 4
- 239000012535 impurity Substances 0.000 description 4
- JXGGISJJMPYXGJ-UHFFFAOYSA-N lithium;oxido(oxo)iron Chemical compound [Li+].[O-][Fe]=O JXGGISJJMPYXGJ-UHFFFAOYSA-N 0.000 description 4
- 239000011163 secondary particle Substances 0.000 description 4
- 239000007784 solid electrolyte Substances 0.000 description 4
- 230000001502 supplementing effect Effects 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 description 3
- 238000002441 X-ray diffraction Methods 0.000 description 3
- 239000011230 binding agent Substances 0.000 description 3
- 239000013078 crystal Substances 0.000 description 3
- 239000003792 electrolyte Substances 0.000 description 3
- 230000007613 environmental effect Effects 0.000 description 3
- 229910002804 graphite Inorganic materials 0.000 description 3
- 239000010439 graphite Substances 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 239000002002 slurry Substances 0.000 description 3
- 238000001228 spectrum Methods 0.000 description 3
- 229920001661 Chitosan Polymers 0.000 description 2
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical compound [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 description 2
- 239000005751 Copper oxide Substances 0.000 description 2
- 239000002228 NASICON Substances 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- 230000002411 adverse Effects 0.000 description 2
- 238000005273 aeration Methods 0.000 description 2
- 229910003481 amorphous carbon Inorganic materials 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 229910021393 carbon nanotube Inorganic materials 0.000 description 2
- 239000002041 carbon nanotube Substances 0.000 description 2
- 239000003575 carbonaceous material Substances 0.000 description 2
- 239000004020 conductor Substances 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 229910000431 copper oxide Inorganic materials 0.000 description 2
- 230000001351 cycling effect Effects 0.000 description 2
- 239000011267 electrode slurry Substances 0.000 description 2
- 239000002223 garnet Substances 0.000 description 2
- 230000016507 interphase Effects 0.000 description 2
- 230000000670 limiting effect Effects 0.000 description 2
- FUJCRWPEOMXPAD-UHFFFAOYSA-N lithium oxide Chemical compound [Li+].[Li+].[O-2] FUJCRWPEOMXPAD-UHFFFAOYSA-N 0.000 description 2
- 229910001947 lithium oxide Inorganic materials 0.000 description 2
- 230000014759 maintenance of location Effects 0.000 description 2
- -1 polytetrafluoroethylene Polymers 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 239000000243 solution Substances 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
- 125000003184 C60 fullerene group Chemical group 0.000 description 1
- 229920000049 Carbon (fiber) Polymers 0.000 description 1
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 1
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 description 1
- 229910018091 Li 2 S Inorganic materials 0.000 description 1
- 229910020719 Li0.33 La0.56 Inorganic materials 0.000 description 1
- 229910003055 Li0.33 La0.57 TiO3 Inorganic materials 0.000 description 1
- 229910021102 Li0.5La0.5TiO3 Inorganic materials 0.000 description 1
- 229910009178 Li1.3Al0.3Ti1.7(PO4)3 Inorganic materials 0.000 description 1
- 229910009274 Li1.4Al0.4Ti1.6 (PO4)3 Inorganic materials 0.000 description 1
- 101150058243 Lipf gene Proteins 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
- 229910004283 SiO 4 Inorganic materials 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 229910006406 SnO 2 At Inorganic materials 0.000 description 1
- 238000003917 TEM image Methods 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- PFYQFCKUASLJLL-UHFFFAOYSA-N [Co].[Ni].[Li] Chemical compound [Co].[Ni].[Li] PFYQFCKUASLJLL-UHFFFAOYSA-N 0.000 description 1
- SRGLWJQVIKHOTJ-UHFFFAOYSA-N [Cu].[Ni].[Li] Chemical compound [Cu].[Ni].[Li] SRGLWJQVIKHOTJ-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
- 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
- 239000006230 acetylene black Substances 0.000 description 1
- 230000004931 aggregating effect Effects 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 238000000498 ball milling Methods 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052793 cadmium Inorganic materials 0.000 description 1
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 description 1
- 239000006229 carbon black Substances 0.000 description 1
- 239000004917 carbon fiber Substances 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
- 238000012512 characterization method Methods 0.000 description 1
- 238000000975 co-precipitation Methods 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
- 150000001875 compounds Chemical class 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000006866 deterioration 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
- 238000009826 distribution Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000011883 electrode binding agent Substances 0.000 description 1
- 239000008151 electrolyte solution Substances 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 description 1
- 238000009422 external insulation Methods 0.000 description 1
- DWYMPOCYEZONEA-UHFFFAOYSA-L fluoridophosphate Chemical compound [O-]P([O-])(F)=O DWYMPOCYEZONEA-UHFFFAOYSA-L 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 230000014509 gene expression Effects 0.000 description 1
- 229910001385 heavy metal Inorganic materials 0.000 description 1
- 150000002430 hydrocarbons Chemical class 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
- 229910000664 lithium aluminum titanium phosphates (LATP) Inorganic materials 0.000 description 1
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 1
- 230000003446 memory effect Effects 0.000 description 1
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000007773 negative electrode material Substances 0.000 description 1
- 229910000480 nickel oxide Inorganic materials 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- GNRSAWUEBMWBQH-UHFFFAOYSA-N oxonickel Chemical compound [Ni]=O GNRSAWUEBMWBQH-UHFFFAOYSA-N 0.000 description 1
- 238000005192 partition Methods 0.000 description 1
- 239000012466 permeate Substances 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 1
- 239000004810 polytetrafluoroethylene Substances 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 235000019422 polyvinyl alcohol Nutrition 0.000 description 1
- 239000005033 polyvinylidene chloride Substances 0.000 description 1
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 239000000661 sodium alginate Substances 0.000 description 1
- 235000010413 sodium alginate Nutrition 0.000 description 1
- 229940005550 sodium alginate Drugs 0.000 description 1
- 238000003980 solgel method Methods 0.000 description 1
- 238000001694 spray drying Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 description 1
- 229910001887 tin oxide Inorganic materials 0.000 description 1
- 238000001291 vacuum drying Methods 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- 125000005287 vanadyl group Chemical group 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Images
Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D15/00—Lithium compounds
- C01D15/08—Carbonates; Bicarbonates
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/362—Composites
- H01M4/366—Composites as layered products
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
- H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
- H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
- H01M2004/028—Positive electrodes
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Inorganic Chemistry (AREA)
- Materials Engineering (AREA)
- Composite Materials (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
The application discloses a composite anode lithium supplement additive and a preparation method and application thereof. The composite positive electrode lithium supplement additive comprises positive electrode lithium supplement material particles, wherein a lithium carbonate coating layer is combined on the surface of the positive electrode lithium supplement material particles, and the lithium carbonate coating layer coats the positive electrode lithium supplement material particles. This application composite anode mends lithium additive sets up the lithium carbonate coating through including anodal lithium material granule surface for contain anodal lithium material granule and keep apart with the external world, guarantee the stability of the lithium effect of mending of composite anode lithium additive, in addition with the high-purity contain and play synergistic effect between the anodal lithium material granule, give this application composite anode mends excellent processing and storage performance of lithium additive. The preparation method of the composite anode lithium supplement additive can ensure that the prepared composite anode lithium supplement additive has stable structure and electrochemical performance, and has high efficiency and production cost saving.
Description
Technical Field
The application belongs to the field of secondary batteries, and particularly relates to a composite positive electrode lithium supplement additive and a preparation method and application thereof.
Background
The oil energy crisis problems in the 60 and 70 th 20 th century forced people to find new alternative new energy sources, with the increasing awareness of environmental protection and energy crisis. Lithium ion batteries are considered to be one of the most promising energy sources because of their advantages of high operating voltage and energy density, relatively small self-discharge level, no memory effect, no pollution from heavy metal elements such as lead and cadmium, and ultra-long cycle life.
In the first charging process of the lithium ion battery, the surface of the negative electrode is usually accompanied by the formation of a solid electrolyte film SEI (solid electrolyte film), and the process consumes a large amount of Li + Meaning Li extracted from the cathode material + Part of the energy is irreversibly consumed, and the reversible specific capacity of the corresponding battery core is reduced. The cathode material, especially silicon-based cathode material, further consumes Li + Causing lithium loss of the anode material and reducing the first coulombic efficiency and the battery capacity of the battery. As in lithium ion battery systems using graphite cathodes, the first charge consumes about 10% of the lithium source. The depletion of the positive lithium source is further exacerbated when high specific capacity anode materials are employed, such as alloys (silicon, tin, etc.), oxides (silicon oxide, tin oxide) and amorphous carbon anodes.
In order to solve the problem of low coulombic efficiency caused by irreversible loss of the negative electrode, the requirement of high energy density can be met by supplementing lithium to the positive electrode besides pre-lithiating the negative electrode material and the pole piece. As the theoretical capacity of the lithium-rich iron-based material reported at present is up to 867mAh/g, the working voltage window is consistent with that of the conventional lithium ion battery, and the lithium-rich iron-based material does not participate in the electrochemical process at the later stage, so that the lithium-rich iron-based material is a lithium supplement additive with wide prospect. The other part of the positive electrode disclosed is added with lithium material Li 5 FeO 4 The material is prepared by a sol-gel method, and has the characteristics of large charge capacity and small discharge capacity when being used as a lithium supplement material of the anode of the lithium ion battery, but the material has harsh environmental adaptability, and the surface layer has large residual alkali and is difficult to process. In the other disclosed carbon-coated lithium ferrite material, a carbon source is adopted for carrying out gas phase coating to isolate the external environment, so that the contact between the lithium ferrite and water in the air is relieved, and the stability of the material is improved; nevertheless, the coating is always difficult to completely isolate from water in the air, leading to deterioration and failure of the material. And residual alkali still exists in the coating layer or between the coating layer and the interface of the lithium ferrite nucleus body, so that the lithium ferrite nucleus is difficult to process.
Disclosure of Invention
The application aims to overcome the defects in the prior art, and provides a composite anode lithium supplement additive and a preparation method thereof, so as to solve the technical problems of non-ideal lithium supplement effect and processability caused by unstable lithium supplement or high residual alkali content of the existing composite anode lithium supplement additive.
Another object of the present invention is to provide a positive electrode and a secondary battery including the same, which solve the technical problems of the prior secondary battery that the first coulomb efficiency and the battery capacity are not ideal.
In order to achieve the above object, in a first aspect of the present application, a composite positive electrode lithium supplement additive is provided. The composite positive electrode lithium supplement additive comprises positive electrode lithium supplement material particles, wherein a lithium carbonate coating layer is further combined on the surface of the positive electrode lithium supplement material particles, the lithium carbonate coating layer coats the positive electrode lithium supplement material particles, and lithium carbonate is generated by reaction of residual alkali contained in the positive electrode lithium supplement material particles.
In a second aspect of the present application, a method for preparing the composite positive electrode lithium supplement additive of the present application is provided. The preparation method of the composite positive electrode lithium supplement additive comprises the following steps:
providing a granular positive electrode lithium supplement material;
and carrying out thermal reaction treatment on the positive electrode lithium supplement material in a carbon dioxide atmosphere, and generating a lithium carbonate coating layer on the surface of the positive electrode lithium supplement material at least to obtain the composite positive electrode lithium supplement additive.
The third aspect of this application provides a positive pole, and this application positive pole includes the mass flow body and combines at the anodal active layer on mass flow body surface, and the anodal active layer is adulterated with this application and is mended the lithium additive or by the compound anodal lithium additive of this application preparation method preparation of mending lithium additive.
In a fourth aspect of the present application, a secondary battery is provided. The secondary battery comprises a positive plate and a negative plate, wherein the positive plate is the positive electrode of the secondary battery.
Compared with the prior art, the method has the following technical effects:
the positive electrode lithium supplement material particles contained in the composite positive electrode lithium supplement additive are rich in lithium, so that the composite positive electrode lithium supplement additive can provide rich lithium, and can be used as a sacrificial agent in the first circle of charging process to release all lithium ions as soon as possible for supplementing irreversible lithium ions consumed by a negative electrode to form an SEI (solid electrolyte interphase) film, so that the abundance of the lithium ions in a battery system is maintained, and the first effect and the whole electrochemical performance of the battery are improved. And the positive electrode lithium supplement material particles have high purity and low residual alkali content, so that the composite positive electrode lithium supplement additive has an excellent lithium supplement effect. Meanwhile, the lithium carbonate coating layer contained in the composite positive electrode lithium supplement additive can effectively play a role in protecting the particles containing the positive electrode lithium supplement material, so that the particles containing the positive electrode lithium supplement material are isolated from moisture and carbon dioxide in the outside, the stability of the lithium supplement effect of the composite positive electrode lithium supplement additive is ensured, and the particles containing the high-purity positive electrode lithium supplement material play a role in synergism, so that the composite positive electrode lithium supplement additive is endowed with excellent processing and storage performances.
The preparation method of the composite positive electrode lithium supplement additive can effectively prepare the core-shell structure composite positive electrode lithium supplement additive with the lithium carbonate coating layer, and the prepared composite positive electrode lithium supplement additive is low in residual alkali content or can eliminate the residual alkali content, so that the prepared composite positive electrode lithium supplement additive has excellent lithium supplement effect and good processing and storage performance. In addition, the preparation method of the composite anode lithium supplement additive can ensure that the prepared composite anode lithium supplement additive has stable structure and electrochemical performance, and has high efficiency and production cost saving.
The positive electrode contains the composite positive electrode lithium supplement additive, so that the components contained in the electrode active layer of the positive electrode are uniformly dispersed, the film layer quality is high, and the electrode plate has excellent electrochemical performance. In the process of charging and discharging, the contained composite positive electrode lithium supplement additive can be used as a lithium source and used as a sacrificial agent in the first circle of charging process to supplement irreversible lithium ions consumed by an SEI (solid electrolyte interphase) film formed by a negative electrode, so that the abundance of the lithium ions in a battery system is maintained, and the first effect and the whole electrochemical performance of the battery are improved.
The secondary battery contains the anode, so that the lithium ion battery has excellent first charge capacity, battery capacity and cycle performance, long service life and stable electrochemical performance.
Drawings
In order to more clearly illustrate the detailed description of the present application or the technical solutions in the prior art, the drawings needed to be used in the detailed description of the present application or the prior art description will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1 is a schematic flow chart of a method for preparing a composite positive electrode lithium supplement additive according to an embodiment of the present disclosure;
FIG. 2 is a TEM image of a composite positive electrode lithium supplement additive of example A1 of the present application;
fig. 3 is an XRD spectrum of the composite positive electrode lithium supplement additive of example A1 herein.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the present application more clearly apparent, the present application is further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
In this application, the term "and/or" describes an association relationship of associated objects, meaning that there may be three relationships, e.g., a and/or B, which may mean: a is present alone, A and B are present simultaneously, and B is present alone. Wherein A and B can be singular or plural. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship.
In the present application, "at least one" means one or more, "a plurality" means two or more. "at least one of the following" or similar expressions refer to any combination of these items, including any combination of the singular or plural items. For example, "at least one (one) of a, b, or c," or "at least one (one) of a, b, and c," may each represent: a, b, c, a-b (i.e. a and b), a-c, b-c, or a-b-c, wherein a, b, and c can be single or multiple respectively.
It should be understood that, in various embodiments of the present application, the sequence numbers of the above-mentioned processes do not mean the execution sequence, some or all of the steps may be executed in parallel or executed sequentially, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.
The terminology used in the embodiments of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in the examples of this application and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
The weight of the related components mentioned in the specification of the embodiments of the present application may not only refer to the specific content of each component, but also refer to the proportional relationship of the weight of each component, and therefore, the proportional enlargement or reduction of the content of the related components according to the specification of the embodiments of the present application is within the scope disclosed in the specification of the embodiments of the present application. Specifically, the mass described in the specification of the embodiments of the present application may be a mass unit known in the chemical industry field such as μ g, mg, g, kg, etc.
The terms "first" and "second" are used for descriptive purposes only and are used for distinguishing purposes such as substances from one another, and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. For example, a first XX may also be referred to as a second XX, and similarly, a second XX may also be referred to as a first XX, without departing from the scope of embodiments of the present application. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.
In a first aspect, embodiments of the present application provide a composite positive electrode lithium supplement additive. The composite positive electrode lithium supplement additive in the embodiment of the application is of a core-shell structure, and specifically comprises positive electrode lithium supplement material particles and a lithium carbonate coating layer combined on the surfaces of the positive electrode lithium supplement material particles, wherein the lithium carbonate coating layer coats the positive electrode lithium supplement material particles. That is, the particles of the positive electrode lithium-containing material constitute a lithium-rich core, and the lithium carbonate coating layer constitutes a shell layer or at least one of the shell layers. Wherein the lithium carbonate is generated by the reaction of residual alkali contained in the positive electrode lithium supplement material-containing particles. In this way, since the positive electrode-containing lithium supplement material particles form a lithium-rich core body in the composite positive electrode lithium supplement additive of the embodiment of the present application, the positive electrode-containing lithium supplement material particles provide a lithium source for supplementing lithium, thereby ensuring that the composite positive electrode lithium supplement additive of the embodiment of the present application can provide abundant lithium during the first charging process, and the lithium is added into an electrode as an additive, and can be used as a "sacrificial agent" during the first charging process, so that all lithium ions contained in the composite positive electrode lithium supplement additive can be released as soon as possible, and the lithium ions are used for supplementing irreversible lithium ions consumed by the negative electrode to form an SEI film.
Meanwhile, the anode lithium supplement material contained in the anode lithium supplement material-containing particles can be a conventional anode lithium supplement material or a newly developed anode lithium supplement material. In an embodiment, the positive electrode lithium supplement material may be a ternary lithium supplement material or a binary lithium supplement material. For example, the positive electrode lithium-supplementing material can include lithium-rich transition metal oxide and Li w A、Li 1+a+ b Al a M b N c Ti 2-a-b-c (PO 4 ) 3 At least one of; wherein w is more than 0 and less than or equal to 5, A is at least one element of C, N, O, P, S, F, B and Se, N is selected from at least one of Si, ge and Sn, M is selected from at least one of Sc, ga, Y and La, B is more than or equal to 0 and less than or equal to 0.5, C is more than or equal to 0 and less than or equal to 0.5, and a + B is more than or equal to 0 and less than or equal to 0.5. When the positive electrode lithium-supplementing material comprises a lithium-rich transition metal oxide, the lithium-rich transition metal oxide comprises Li 2+ y Ni 1-x Q x O 2 Wherein x is more than or equal to 0 and less than or equal to 1, y is more than or equal to 0.2 and less than or equal to 0.2, and Q comprises at least one of Cu, co, mg, zn, mn, al, zr, ti and Fe. In a specific embodiment, li 2+y Ni 1-x Q x O 2 May be Li 2 NiO 2 ，Li 2+y Ni 1-x Cu x O 2 And the like. In the other partsIn a specific embodiment, the positive electrode lithium-supplementing material contained in the positive electrode lithium-supplementing material-containing particles may include, but not exclusively, a positive electrode lithium-supplementing material having a chemical formula of Li 2 MnO 2 、Li 6 MnO 4 、jLiFeO 2 ·kLi 2 O·lM d O e 、Li 6 CoO 4 、Li 2 NiO 2 、Li 4 SiO 4 、Li 2 S、Li 3 N、Li 8 SnO 6 、Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 At least one of (1). Wherein, the chemical formula is jLiFeO 2 ·kLi 2 O·lQ d O e Wherein j + k is more than or equal to 0.98, l is less than or equal to 0.02, k/j is more than or equal to 1.8 and less than or equal to 2.1, e/d is more than or equal to 1 and less than or equal to 2.5, and Q is at least one of Ni, co, mn, ti, al, cu, V and Zr. The positive electrode lithium supplement materials are rich in lithium, and can release lithium ions in the first circle of charging process to play an effective lithium supplement role. When the positive electrode lithium supplement materials also contain reversible lithium, the positive electrode lithium supplement materials can be used as positive electrode active materials after the lithium supplement effect is completed, so that the composite positive electrode lithium supplement additive disclosed by the embodiment of the application can improve the first charge-discharge performance, can be used as the positive electrode active materials, and has higher reversible capacity.
In an embodiment, the positive electrode lithium supplement material-containing particles may be at least one of primary particles and secondary particles. The D50 particle diameter of the positive electrode lithium-supplementing material-containing particles may be 0.5 to 30 μm, more preferably 0.5 to 25 μm, and still more preferably 1 to 15 μm. When the positive electrode lithium supplement material-containing particles are primary particles, the D50 particle size of the primary particles is 20-300nm; when the positive electrode lithium-containing material particles are secondary particles, the D50 particle diameter of the secondary particles is 0.5 to 30 μm. Wherein, the secondary particles are agglomerated particles formed by aggregating more than one primary particles. By controlling the particle size form and the particle size of the particles containing the positive electrode lithium supplement material, the processability of the composite positive electrode lithium supplement additive in the preparation of lithium battery slurry is improved on the basis of providing rich lithium ions, wherein more lithium can be extracted from the composite positive electrode lithium supplement additive with smaller primary particle size.
In the above embodiments, the content of the cathode lithium supplement material contained in the cathode lithium supplement material-containing particles can be controlled and increased by the conditions of the preparation process, for example, in the embodiments, the content of the cathode lithium supplement material contained in the cathode lithium supplement material-containing particles can be controlled to be greater than or equal to 75%, and further can be 95% and less than 100%. Namely, the purity of the positive electrode lithium-supplementing material particles can be controlled to be more than 95%. In particular, as described below, when the lithium carbonate coating layer included in the composite positive electrode lithium supplement additive of the embodiments of the present invention is formed in situ by a thermal reaction between a carbon source and a positive electrode lithium supplement material serving as positive electrode lithium supplement material particles, impurities, in particular residual alkali impurities, in the positive electrode lithium supplement material particles can be further reduced, and the purity of the positive electrode lithium supplement material particles can be improved, thereby improving the lithium supplement effect, the processing and the storage performance, and the like of the composite positive electrode lithium supplement additive of the embodiments of the present invention.
In addition, although the particles of the positive electrode lithium supplement material in the above embodiments are rich in lithium, they are unstable in water and carbon dioxide, and they are liable to react with water and carbon dioxide, thereby reducing the lithium supplement effect, processability and storability of the composite positive electrode lithium supplement additive in the embodiments of the present application. Meanwhile, the existing lithium supplement materials generally contain residual alkali formed by processing, and the residual alkali can further reduce the processing performance of the lithium supplement materials, for example, the viscosity of the lithium supplement materials containing the residual alkali is increased sharply, and the lithium supplement materials gel rapidly and lose fluidity, so that the subsequent processing treatment cannot be carried out. Therefore, in addition to the positive electrode lithium supplement material-containing particles in the above examples, the lithium carbonate coating layer contained in the composite positive electrode lithium supplement additive in the above examples was coated on the positive electrode lithium supplement material particles, and the lithium carbonate was generated by the reaction of the residual alkali contained in the positive electrode lithium supplement material-containing particles. Therefore, the lithium carbonate coating layer can effectively protect the particles containing the positive electrode lithium supplement material, so that the particles containing the positive electrode lithium supplement material are isolated from moisture and carbon dioxide in the outside particularly, and the content of residual alkali in the particles containing the positive electrode lithium supplement material is effectively reduced. Due to the existence of the lithium carbonate coating layer and the forming mode of the lithium carbonate coating layer, the content of the particles containing the positive electrode lithium supplement material, particularly the residual alkali on the surface, is at least effectively reduced or the residual alkali can be basically eliminated, so that the processing difficulty caused by the residual alkali is effectively avoided, namely the composite positive electrode lithium supplement additive in the embodiment of the application has excellent processing performance, and the gram capacity exertion of the composite positive electrode lithium supplement additive is stimulated. Based on the above-mentioned effect of the lithium carbonate coating layer, the lithium carbonate coating layer is preferably a dense coating layer to improve the protective effect of the particles containing the positive electrode lithium supplement material and to improve the effect of the particles containing the positive electrode lithium supplement material on insulating adverse factors such as moisture and carbon dioxide in the outside during storage or processing.
In the examples, the thickness of the lithium carbonate coating layer may be controlled to be 1 to 200nm, more preferably 1 to 100nm, and still more preferably 5 to 30nm. The lithium carbonate coating layer with the thickness in the range can improve the external insulation and protection effects of the lithium carbonate coating layer.
In an embodiment, the lithium carbonate coating layer may be formed in situ by a thermal reaction between a carbon source and a positive electrode lithium supplement material serving as the positive electrode lithium supplement material particles. Therefore, on one hand, the content of residual alkali contained in the positive electrode lithium supplement material, particularly the content of residual alkali on the surface of particles can be effectively reduced, and the adverse effects of residual alkali on the lithium supplement, storage, processing and other performances of the particles containing the positive electrode lithium supplement material are avoided; on the other hand, the bonding strength between the lithium carbonate coating layer and the particles containing the positive electrode lithium supplement material is effectively enhanced through in-situ growth of the lithium carbonate coating layer, and the structural stability of the composite positive electrode lithium supplement additive in the embodiment of the application is improved.
In a further embodiment, the surface layer of the positive electrode lithium supplement material particles is also doped with lithium carbonate, and the content of the doped lithium carbonate is gradually decreased along the direction from the surface of the positive electrode lithium supplement material particles to the interior of the particles. Further, for example, in the process that the lithium carbonate coating layer is formed in situ by thermally reacting the carbon source with the positive electrode lithium supplement material as the positive electrode lithium supplement material particles, by controlling the thermal reaction, lithium carbonate is gradually formed as the surface residual alkali of the positive electrode lithium supplement material particles is gradually reacted with the carbon source, lithium carbonate gradually permeates into the surface layer of the positive electrode lithium supplement material particles, and lithium carbonate formed on the surface of the positive electrode lithium supplement material particles forms the lithium carbonate coating layer, and desirably forms a dense lithium carbonate coating layer. In this way, the lithium carbonate with the gradient content is doped in the surface layer of the positive electrode lithium supplement material particles, so that the residual alkali content of the positive electrode lithium supplement material particles can be further reduced, the lithium supplement effect, the storage and processing performance of the particles are improved, and the bonding strength of the lithium carbonate coating layer and the positive electrode lithium supplement material particles is improved.
Based on the above examples, the total mass content of lithium carbonate in the lithium supplement additive for the composite positive electrode in the examples of the present application may be controlled to be 0.1 to 10wt%, and further may be 0.3 to 5wt%. The content of the residual alkali in the composite positive electrode lithium supplement additive is further reduced by controlling the content of the lithium carbonate, so that the lithium supplement effect, the processing and storage performances and the like of the composite positive electrode lithium supplement additive in the embodiment of the application are further improved, and the gram capacity of the composite positive electrode lithium supplement additive is stimulated to play.
In a further embodiment, based on the composite positive electrode lithium supplement additive in each of the above embodiments, the composite positive electrode lithium supplement additive in the embodiment of the present application further includes a functional encapsulation layer, the functional encapsulation layer is laminated and bonded on the outer surface of the lithium carbonate coating layer facing away from the positive electrode lithium supplement material particles, and the functional encapsulation layer covers the lithium carbonate coating layer. The related properties of the composite positive electrode lithium supplement additive in the embodiment of the application, such as electron conductivity and/or ion conductivity, can be improved by additionally arranging the functional packaging layer, so that the conductivity or lithium ion conductivity of the composite positive electrode lithium supplement additive in the embodiment of the application is improved. And the lithium ion battery can also play a role in synergism with the lithium carbonate coating layer, such as the effect of isolating the external environment and the performance synergism such as the effect of lithium supplement, and the like, so that the electrochemical performance related to the composite positive electrode lithium supplement additive in the embodiment of the application is improved. In an embodiment, the functional encapsulation layer may be an electronic conductor encapsulation layer or an ionic conductor encapsulation layer or a composite layer structure formed by the electronic conductor encapsulation layer and the ionic conductor encapsulation layer. When the functional packaging layer comprises the electronic conductor packaging layer and the ion conductor packaging layer at the same time, the lithium carbonate coating layer is coated on the electronic conductor packaging layer or the ion conductor packaging layer.
When the functional packaging layer contains the electronic conductor packaging layer, the electronic conductor packaging layer can enhance the electronic conductivity of the functional packaging layer, so that the electronic conductivity of the composite positive electrode lithium supplement additive is enhanced, and the internal impedance of the electrode is favorably reduced; meanwhile, during and after the release of the positive electrode lithium supplement material-containing particles as a sacrificial material, the electronic conductor packaging layer can be reused, and the auxiliary effect of the conductive agent is achieved in the electrode. In an embodiment, the thickness of the electronic conductor encapsulation layer may be 1-100nm, further 1-50nm, and further 2-20nm. In other embodiments, the mass content of the electron conductor encapsulation layer in the lithium supplement additive for the composite positive electrode is 0.1-30%, further 0.1-10%, and more preferably 0.5-5%.
In an embodiment, the material of the electronic conductor encapsulation layer includes at least one of a carbon material and a conductive oxide. In particular embodiments, the carbon material includes at least one of amorphous carbon, carbon nanotubes, graphite, carbon black, graphene, and the like. In a specific embodiment, the conductive oxide may include In 2 O 3 、ZnO、SnO 2 At least one of (1). The electronic conductivity of the electronic conductor packaging layer can be further improved by adjusting the thickness and the material of the electronic conductor packaging layer.
When the functional packaging layer contains the ion conductor packaging layer, the ion conductor packaging layer can enhance the ion conductivity of the functional packaging, so that the ion conductivity of the composite positive electrode lithium supplement additive is enhanced, the lithium ions of a karyon are transported outwards, the separation efficiency of the composite positive electrode lithium supplement additive can be improved, and the lithium supplement effect of the composite positive electrode lithium supplement additive is improved. Meanwhile, after the lithium ion is released by the positive electrode lithium supplement material-containing particles as a sacrificial product, the ion conductor packaging layer can be utilized secondarily, and the auxiliary effect of enhancing ion transmission is achieved in the electrode. In an embodiment, the thickness of the ion conductor encapsulation layer may be 1-200nm, further 1-50nm, and further 2-20nm. In another embodiment, the material of the ion conductor encapsulation layer includes at least one of perovskite type, NASICON type, and garnet type. In a specific embodiment, the perovskite type comprises Li 3x La 2/3-x TiO 3 (LLTO), in particular Li 0.5 La 0.5 TiO 3 、Li 0.33 La 0.57 TiO 3 、Li 0.29 La 0.57 TiO 3 、Li 0.33 Ba 0.25 La 0.39 TiO 3 、(Li 0.33 La 0.56 ) 1.005 Ti 0.99 Al 0.01O3 、Li 0.5 La 0.5 Ti 0.95 Zr 0.05 O 3 Etc., of the NASICON type such as but not limited to Li 1.4 Al 0.4 Ti 1.6 (PO 4 ) 3 (LATP), garnet type comprising Li 7 La 3 Zr 2 O 12 (LLZO)、Li 6·4 La 3 Zr 1·4 Ta 0·6 O 12 ，Li 6.5 La 3 Zr 1.5 Ta 0.5 O 12 At least one of (1). The ionic conductivity of the ion conductor encapsulation layer 23 can be further improved by adjusting the thickness and material thereof.
In addition, according to the requirement, the outer surface of the functional encapsulation layer may further include other layer structures, for example, a coating layer such as a conductive organic substance may be included, for example, a composite coating layer structure is formed with at least one of the electronic conductor encapsulation layer and the ionic conductor encapsulation layer. For example, when the other coating layers include a conductive organic coating layer, the conductive organic coating layer is coated on the outer surface of the electronic conductor packaging layer and the ion conductor packaging layer.
Based on the above embodiments, it is detected that the D50 particle size of the composite positive electrode lithium supplement additive in the embodiments of the present application substantially satisfies: 1 μm to 30 μm, and further 2 μm to 25 μm. Further, the composite positive electrode lithium supplement additive in the embodiment of the application has excellent electrochemical properties, for example, the first charge gram capacity of the composite positive electrode lithium supplement additive is more than 420, further 420-480mAh/g, and the reversible capacity of the composite positive electrode lithium supplement additive is more than 120, further 120-190mAh/g. The BET specific surface of the composite anode lithium supplement additive is 0.1-40m 2 /g。
In a second aspect, embodiments of the present application also provide a preparation method of the above composite positive electrode lithium supplement additive. The preparation process flow of the composite positive electrode lithium supplement additive in the embodiment of the application is shown in fig. 1, and comprises the following steps:
s01: providing a granular positive electrode lithium supplement material;
s02: and carrying out thermal reaction treatment on the positive electrode lithium supplement material in a carbon dioxide atmosphere, and generating a lithium carbonate coating layer on the surface of the positive electrode lithium supplement material at least to obtain the composite positive electrode lithium supplement additive.
The particulate positive electrode lithium supplement material in step S01 is a material that forms particles containing the positive electrode lithium supplement material contained in the composite positive electrode lithium supplement additive according to the example of the above application. The lithium carbonate coating layer in step S02 is also a lithium carbonate coating layer contained in the composite positive electrode lithium supplement additive in the example of the above application. Therefore, the particulate positive electrode lithium supplement material in step S01 and the lithium carbonate coating layer in step S02 have the relevant properties including the material type, which are as described in the foregoing application, and the positive electrode lithium supplement material-containing particles and the lithium carbonate coating layer contained in the composite positive electrode lithium supplement additive in the embodiment are not repeated for saving the description of the application.
In an embodiment, the particulate positive electrode lithium supplement material in step S01 may be prepared according to an existing preparation method of a corresponding positive electrode material, or may be prepared according to an improved method. In a specific embodiment, the particulate positive electrode lithium supplement material is formed by calcining a corresponding positive electrode lithium supplement material precursor in a protective atmosphere. The calcination treatment can be determined according to the performance of a precursor of the corresponding positive electrode lithium supplement material, for example, when the material is a nickel-based lithium-rich lithium supplement material, the calcination treatment can be to preserve the temperature of the precursor mixture of the nickel-based lithium-rich lithium supplement material at 400-500 ℃ for 200-300min in an inert gas atmosphere, and then to calcine the mixture for 600-720min at 650-750 ℃ to obtain the nickel-based lithium-rich lithium supplement material.
In step S02, during the thermal reaction treatment, the carbon dioxide atmosphere reacts with residual alkali contained in the particulate positive electrode lithium supplement material, particularly residual alkali on the surface or on the surface layer, to generate lithium carbonate. In the examples, the temperature of the thermal reaction treatment is 250 to 300 ℃. At the temperature, the lithium carbonate generation reaction efficiency between the carbon dioxide and the residual alkali can be effectively improved. The time of the thermal reaction treatment should be at least as long as the lithium carbonate coating layer is formed on the surface of the particulate positive electrode lithium supplement material, that is, the residual alkali on the surface is sufficiently reacted to form lithium carbonate as much as possible. Further, the thickness or/and density of the lithium carbonate coating layer can be controlled by controlling the time of the thermal reaction treatment, and the doping content and gradient distribution depth of the lithium carbonate in the surface layer of the granular positive electrode lithium supplement material can be further controlled, for example, the thermal reaction treatment is carried out at the temperature of 250-300 ℃ for 1-30min.
In an embodiment, the carbon dioxide in the thermal reaction treatment may further include C 1 -C 4 Alcohols of (2) C 1 -C 4 Ethers of (2) and (C) 1 -C 4 Ketones of (2), C 1 -C 4 At least one of the hydrocarbon compounds of (a). The carbon sources can effectively react with residual alkali to generate lithium carbonate. In the examples, the carbon dioxide atmosphere is to convert the CO 2 The anode lithium-doped material is introduced into the thermal reaction treatment environment at a constant flow rate and surrounds the anode lithium-doped material to perform sufficient thermal reaction treatment. Wherein the CO is 2 Should ensure that the CO is present 2 Fully contacts with the anode lithium supplement material and reacts, namely ensures CO 2 The reaction is carried out in excess, for example, at a rate of 0.4L/min, but not exclusively.
Or in another embodiment, when the positive electrode lithium supplement material in the step S01 is ensured to be in the preparation process, and the precursor of the positive electrode lithium supplement material contains a carbonate component, the positive electrode lithium supplement material is formed by sintering the precursor containing the carbonate, and CO generated in the sintering process is collected 2 A gas; when the temperature of the positive electrode lithium supplement material to be generated is reduced to the thermal reaction treatment, the collected CO is treated 2 The gas is introduced into the environment where the positive electrode lithium-doped material is located to form a carbon dioxide atmosphere, and a thermal reaction treatment is performed. Thus, energy consumption and raw materials can be saved, the cost is reduced, and the environmental protection is improved.
After step S03, if necessary, another layer structure may be further formed on the surface of the coating layer containing lithium carbonate after the heat treatment in step S02, for example, the other layer structure may be an electron conductor encapsulation layer and an ion conductor encapsulation layer contained in the composite positive electrode lithium supplement additive in the embodiment of the above application, and may further include a coating layer such as a conductive organic substance. When the other coating layers comprise conductive organic coating layers, the conductive organic coating layers are coated on the outer surfaces of the electronic conductor packaging layers or the ion conductor packaging layers. The forming method can also adopt the methods of in-situ mixing treatment, spray drying and the like.
Therefore, the preparation method of the composite positive electrode lithium supplement additive in the embodiment of the present application can effectively prepare the composite positive electrode lithium supplement additive with the core-shell structure, specifically, the composite positive electrode lithium supplement additive containing the lithium carbonate coating layer to coat the positive electrode lithium supplement material particles is prepared, the content of residual alkali in the prepared composite positive electrode lithium supplement additive is low or the residual alkali is eliminated, the compactness of the functional encapsulation layer is improved, the composite positive electrode lithium supplement additive has the excellent lithium supplement effect and good processing and storage performances of the composite positive electrode lithium supplement additive in the embodiment of the present application, and the relevant performances of the composite positive electrode lithium supplement additive prepared by optimizing the materials and process conditions of the positive electrode lithium supplement material particles and the lithium carbonate coating layer or the further functional encapsulation layer can be controlled. In addition, the preparation method of the composite anode lithium supplement additive can ensure that the prepared composite anode lithium supplement additive has stable structure and electrochemical performance, and has high efficiency and production cost saving.
In a third aspect, an embodiment of the present application further provides a positive electrode. The positive electrode of the embodiment of the application comprises a current collector and a positive active layer combined on the surface of the current collector, wherein the positive active layer is doped with the composite positive lithium supplement additive of the embodiment of the application. Since the positive electrode of the embodiment of the present application contains the composite positive electrode lithium supplement additive of the embodiment of the present application, during charging and discharging, the composite positive electrode lithium supplement additive contained in the positive electrode plays the above role, and can be used as a lithium source to be consumed first as a "sacrificial agent" during the first cycle of charging, so as to supplement irreversible lithium ions consumed by the negative electrode to form an SEI film, thereby maintaining the abundance of lithium ions in a battery system, and improving the first effect and the overall electrochemical performance of the battery.
In one embodiment, the mass content of the composite positive electrode lithium supplement additive in the positive electrode active layer in the embodiment of the application can be 0.1-15wt%; further, it may be 1 to 5wt%. The positive active layer comprises a positive active material, a binder and a conductive agent besides the composite positive lithium supplement additive, wherein the binder can be a common electrode binder, such as 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 derivative. In the embodiment of the present application, the conductive agent may be a commonly used conductive agent, such as one or more of graphite, carbon black, acetylene black, graphene, carbon fiber, C60, and carbon nanotube. The positive active material may include one or more of lithium cobaltate, lithium manganate, lithium iron phosphate, lithium vanadium phosphate, lithium vanadyl fluorophosphate, lithium titanate, lithium nickel cobalt manganate, and lithium nickel cobalt aluminate.
In an embodiment, the preparation process of the positive electrode may be: mixing the positive electrode active material, the composite positive electrode lithium supplement additive, the conductive agent and the binder to obtain electrode slurry, coating the electrode slurry on a current collector, and drying, rolling, die-cutting and the like to prepare the positive electrode piece.
In a fourth aspect, embodiments of the present application further provide a secondary battery. The secondary battery of the embodiment of the present application includes necessary components such as a positive electrode sheet, a negative electrode sheet, a separator, and an electrolyte, and of course, includes other necessary or auxiliary components. The positive plate is the positive electrode in the embodiment of the present application, that is, the positive active layer contained in the positive plate contains the composite positive lithium supplement additive in the embodiment of the present application.
Because the secondary battery of the embodiment of the application contains the composite positive electrode lithium supplement additive of the embodiment of the application, the secondary battery of the embodiment of the application has excellent lithium supplement performance or further has ion conductivity and/or electron conductivity, and the first charge capacity, the battery capacity and the cycle performance of the secondary battery are endowed, the service life is long, and the electrochemical performance is stable.
The composite positive electrode lithium supplement additive, the preparation method and the application thereof, etc. in the embodiments of the present application are illustrated by a plurality of specific examples below.
1. The embodiment of the composite positive electrode lithium supplement additive and the preparation method thereof comprises the following steps:
example A1
This example provides a composite positive electrode lithium supplement additive anda method for preparing the same. The composite positive electrode lithium supplement additive comprises Li 2 NiO 2 Lithium-supplementing material particles and coated Li 2 NiO 2 A lithium carbonate coating layer of the lithium supplement material particles.
The preparation method of the composite positive electrode lithium supplement additive comprises the following steps:
s1, mixing lithium carbonate and a nickel source material obtained by coprecipitation according to the proportion that Li to Ni =2.0-2.2:1 to obtain a uniform precursor mixture;
s2, preserving the temperature of the precursor mixture at 400 ℃ for 200-min in an inert gas atmosphere, and then heating to 750 ℃ and calcining for 720min to obtain Li 2 NiO 2 Ni-based lithium-rich anode material and collecting CO in tail gas of tube furnace 2 A gas;
s3, when the temperature is cooled to 300 ℃ along with the furnace, introducing the collected CO into the tubular furnace at the speed of 0.4L/min 2 The gas length reaches 25min 2 Firstly, the lithium carbonate reacts with the residual lithium oxide impurities to generate the lithium carbonate doped in Li 2 NiO 2 In (5), with increasing aeration time, product Li 2 NiO 2 Externally forming a dense layer of Li 2 CO 3 A shell, which is coated with Li 2 NiO 2 And (3) granules.
S4, cooling to room temperature in an inert gas atmosphere to obtain the nickel-based lithium-rich cathode material Li with the core-shell structure 2 NiO 2 @Li 2 CO 3 。
Detected, li 2 NiO 2 The D50 particle diameter of the lithium-supplementing material particles is 1.35 mu m, and the specific surface area is 0.35m 2 The thickness of the lithium carbonate coating layer is 10nm.
Example A2
The embodiment provides a composite positive electrode lithium supplement additive and a preparation method thereof. Compared with the composite positive electrode lithium supplement additive in the embodiment 1, the composite positive electrode lithium supplement additive is characterized in that a compact carbon coating layer is further coated on the outer surface of the lithium carbonate coating layer.
The preparation method of the composite positive electrode lithium supplement additive comprises the following steps:
steps S1 to S3 are the same as steps S1 to S3 in embodiment 1;
s4, under the inert gas atmosphere, mixing the positive electrode lithium supplement additive and the graphene source in the step S3 according to the mass ratio of 100:2, preserving the heat for 80min at 500 ℃ after mixing treatment, thereby generating a carbon coating layer on the surface of the lithium carbonate coating layer to obtain Li 2 NiO 2 @Li 2 CO 3 @C。
The thickness of the lithium carbonate coating layer is 10.5nm and the thickness of the carbon coating layer is 15nm.
Example A3
The embodiment provides a composite positive electrode lithium supplement additive and a preparation method thereof. The composite positive electrode lithium supplement additive comprises Li 2 Ni 0.5 Cu 0.5 O 2 Lithium-supplementing material particles and coated Li 2 Ni 0.5 Cu 0.5 O 2 A lithium carbonate coating layer for covering the lithium supplement material particles, and a carbon layer for covering the lithium carbonate coating layer.
The preparation method of the composite positive electrode lithium supplement additive comprises the following steps:
s1, fully mixing lithium hydroxide, nickel oxide and copper oxide materials according to the proportion of Li to Ni to Cu = 2;
s2, preserving the temperature of the precursor mixture at 450 ℃ for 250min under the inert gas atmosphere, heating to 7000 ℃, calcining for 650min, and cooling along with the furnace to obtain the lithium nickel copper anode material Li 2 N 0.5 Cu 0.5 O 2 ；
S3, when the temperature is cooled to 300 ℃ along with the furnace, introducing the collected CO into the tubular furnace at the speed of 0.4L/min 2 The gas length can reach 30min 2 Firstly, the lithium carbonate reacts with the residual lithium oxide impurities to generate the lithium carbonate doped in Li 2 Ni 0.5 Cu 0.5 O 2 In (5), with increasing aeration time, product Li 2 Ni 0.5 Cu 0.5 O 2 Externally forming a dense layer of Li 2 CO 3 A shell, which is coated with Li 2 Ni 0.5 Cu 0.5 O 2 And (3) granules.
S4, adding the lithium to the positive electrode in the step S3 in an inert gas atmosphereThe additive and the graphene carbon source are mixed according to the mass ratio of 100:2, preserving the heat for 80min at 500 ℃ after mixing treatment, thereby generating a carbon coating layer on the surface of the lithium carbonate coating layer to obtain Li 2 Ni 0.5 Cu 0.5 O 2 @Li 2 CO 3 @C。
By detection, li 2 Ni 0.5 Cu 0.5 O 2 The D50 particle diameter of the lithium supplement material particles is 1.40 mu m, the thickness of the lithium carbonate coating layer is 9.8nm, and the thickness of the carbon coating layer is 14nm.
Example A4
The embodiment provides a composite positive electrode lithium supplement additive and a preparation method thereof. The composite positive electrode lithium supplement additive comprises Li 2 Ni 0.5 Co 0.5 O 2 Lithium-supplementing material particles and coated Li 2 Ni 0.5 Co 0.5 O 2 A lithium carbonate coating layer for covering the lithium supplement material particles, and a carbon layer for covering the lithium carbonate coating layer.
This example is different from example 3 only in that the copper oxide in step S1 is cobalt oxide, and other conditions and parameters are completely the same as those in example 3.
Detected, li 2 Ni 0.5 Co 0.5 O 2 The D50 particle diameter of the lithium supplement material particles is 1.35 mu m, the thickness of the lithium carbonate coating layer is 11nm, and the thickness of the carbon coating layer is 15nm.
Comparative example A1
The comparative example provides a positive electrode lithium supplement additive and a method of making the same. The positive electrode lithium supplement additive contained no lithium carbonate coating layer, compared to the composite positive electrode lithium supplement additive in example 1.
The preparation method of the composite positive electrode lithium supplement additive comprises the following steps:
refer to steps S1 to S2 in example 1.
Comparative example A2
The comparative example provides a positive electrode lithium supplement additive and a method of making the same. The positive electrode lithium supplement additive did not contain a lithium carbonate coating layer and a carbon layer, as compared with the composite positive electrode lithium supplement additive in example 3.
The preparation method of the composite positive electrode lithium supplement additive comprises the following steps:
refer to steps S1 to S2 in example 3.
Comparative example A3
The comparative example provides a positive electrode lithium supplement additive and a method of making the same. The positive electrode lithium supplement additive contained no lithium carbonate coating layer and no carbon layer, compared to the composite positive electrode lithium supplement additive in example 4.
The preparation method of the composite positive electrode lithium supplement additive comprises the following steps:
refer to steps S1 to S2 in example 4.
2. The lithium ion battery comprises the following embodiments:
the present examples A1 to A4 and the comparative examples A1 to A3 respectively provide a lithium ion battery. The lithium ion batteries are assembled into the lithium ion batteries according to the following methods:
positive plate: the composite positive electrode lithium supplement additives provided in examples A1 to A4 and comparative examples A1 to A3 were used as the positive electrode lithium supplement additives of examples B1 to B4 and comparative examples B1 to B3 of the lithium ion battery, respectively, the composite positive electrode lithium supplement additive was mixed with lithium cobaltate at a mass ratio of 5: 95 to obtain a mixture, and the mixture was mixed with polyvinylidene fluoride and SP-Li at a ratio of 95:3:2, mixing, ball-milling and stirring to obtain positive slurry, coating the positive slurry on the surface of an aluminum foil, rolling, and carrying out vacuum drying at 110 ℃ overnight to obtain a positive pole piece;
negative electrode: a lithium metal sheet;
electrolyte solution: ethylene carbonate and ethyl methyl carbonate were mixed in a volume ratio of 3 6 Forming an electrolyte, liPF 6 The concentration of (A) is 1mol/L;
diaphragm: polypropylene microporous partition;
assembling the lithium ion battery: and assembling the lithium ion battery in an inert atmosphere glove box according to the assembling sequence of the lithium metal sheet, the diaphragm, the electrolyte and the positive plate.
3. Correlation performance testing
1. Relevant testing of composite positive electrode lithium supplement additives
1.1 TEM analysis of the composite anode lithium supplement additive:
the composite positive electrode lithium supplement additives provided in the above examples A1 to A4 and comparative examples A1 to A3 were respectively subjected to TEM analysis, wherein the TEM of example A1 is shown in fig. 2. As can be seen from fig. 2, the lithium carbonate coating layer can be uniformly coated on the surface of the lithium supplement material, and it is described that the carbon source can sufficiently react with the residual alkali on the surface of the lithium supplement material by the thermal reaction treatment, so that a thin and uniform coating layer can be formed on the surface of the lithium supplement material.
1.2X-ray diffraction (XRD) characterization of composite positive electrode lithium supplement additive:
XRD analysis was performed on the composite positive electrode lithium supplement additives provided in examples A1 to A4 and comparative examples A1 to A3, respectively, wherein XRD of example A1 is shown in fig. 3.
As can be seen from the XRD spectrum, the XRD spectrum peaks of the lithium supplement additive in example A1 are matched with Li with unit cell of binary orthorhombic phase structure and space group of crystal structure of Immm in a crystal structure database 2 NiO 2 The standard peak position of the material is shown in fig. 3, because the lithium carbonate coating layer has a small content, the peak intensity is weak, and the position of part of the peak is associated with Li 2 NiO 2 Overlapping; other examples provide that the XRD patterns of the lithium supplement additives are similar to those of fig. 3, and the peaks of the XRD patterns all match the binary orthorhombic structure of the unit cells in the crystal structure database.
2. The lithium ion battery comprises the following embodiments:
the electrochemical performance of each lithium ion battery assembled in the embodiment of the lithium ion battery is tested, and the test conditions are as follows:
and charging the button cell to 4.3V at a constant current and constant voltage of 0.05C, discharging to 2.8V at a cut-off current of 0.01C, standing for 5min, discharging at a rate of 0.05C, charging to 4.3V at a constant current and constant voltage of 0.2C, discharging to 2.8V at a cut-off current of 0.01C, standing for 5min, and discharging at a rate of 0.2C, and circulating for 100 circles.
The test results are shown in table 1 below:
TABLE 1
As can be seen from table 1, the thicknesses of the lithium carbonate coating layers in the examples B1 to B2 are all around 10nm, the first charge gram specific capacities are all over 169mAh/g, the gram capacities are increased by 20 to 27mAh/g, and the capacity retention rates are also over 90% after cycling for 100 cycles at a rate of 0.2C, while in the comparative examples B1 to B2, since the positive electrode lithium supplement material not coated with lithium carbonate is included, the first charge gram specific capacity average value is lower than 167mAh/g, the gram capacities are also increased by 14 to 17mAh/g, and the capacity retention rates are only around 86% after cycling for 100 cycles at a rate of 0.2C, which indicates that the composite lithium supplement positive electrode material prepared by the present application has excellent lithium supplement effects and good processing and storage properties, and gives the present application excellent electrochemical properties to the electrode sheet.
The above examples only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present application. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, and these are all within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (12)
1. The composite positive electrode lithium supplement additive comprises positive electrode lithium supplement material particles, and is characterized in that: and a lithium carbonate coating layer is combined on the surface of the positive electrode lithium supplement material-containing particles, the positive electrode lithium supplement material-containing particles are coated by the lithium carbonate coating layer, and the lithium carbonate is generated by the reaction of residual alkali contained in the positive electrode lithium supplement material-containing particles.
2. The composite positive electrode lithium supplement additive according to claim 1, wherein: the lithium carbonate coating layer is a compact coating layer; and/or
The thickness of the lithium carbonate coating layer is 1-200nm and/or
The lithium carbonate coating layer is formed by in-situ generation of a carbon source and a positive electrode lithium supplement material serving as the positive electrode lithium supplement material particles through a thermal reaction.
3. The composite positive electrode lithium supplement additive according to claim 1 or 2, wherein: and lithium carbonate is also doped in the surface layer of the positive electrode lithium supplement material particles, and the content of the doped lithium carbonate is gradually reduced along the direction from the surface of the positive electrode lithium supplement material particles to the interior of the particles.
4. The composite positive electrode lithium supplement additive according to claim 1 or 2, wherein: the positive electrode lithium supplement material contained in the positive electrode lithium supplement material particles comprises lithium-rich transition metal oxide and Li w A、Li 1+x+y Al x M y N z Ti 2-x-y-z (PO 4 ) 3 Wherein w is more than 0 and less than or equal to 5, A is at least one element of C, N, O, P, S, F, B and Se, N is selected from at least one of Si, ge and Sn, M is selected from at least one of Sc, ga, Y and La, B is more than or equal to 0 and less than or equal to 0.5, C is more than or equal to 0 and less than or equal to 0.5, and a + B is more than or equal to 0 and less than or equal to 0.5; and/or
The D50 particle size of the positive electrode lithium supplement material particles is 0.5-30 mu m; and/or
The content of the anode lithium supplement material contained in the anode lithium supplement material particles is greater than or equal to 75% and less than 100%.
5. The composite positive electrode lithium supplement additive according to claim 4, wherein: the lithium-rich transition metal oxide comprises Li 2+y Ni 1-x Q x O 2 Wherein x is more than or equal to 0 and less than or equal to 1, y is more than or equal to 0.2 and less than or equal to 0.2, and Q comprises at least one of Cu, co, mg, zn, mn, al, zr, ti and Fe.
6. The composite positive electrode lithium supplement additive according to any one of claims 1, 2, and 5, wherein: and a functional packaging layer is combined on the outer surface of the lithium carbonate coating layer deviating from the positive electrode lithium supplement material particles, and the functional packaging layer coats the lithium carbonate coating layer.
7. The composite positive electrode lithium supplement additive according to any one of claims 1, 2, and 5, wherein: the D50 particle size of the composite positive electrode lithium supplement additive is 1-30 mu m; and/or
The first charge gram capacity of the composite positive electrode lithium supplement additive is more than 420 mAh/g; and/or
The reversible capacity of the composite anode lithium supplement additive is more than 120 mAh/g; and/or
The BET specific surface area of the composite anode lithium supplement additive is 0.1-40m 2 /g。
8. A preparation method of the composite positive electrode lithium supplement additive comprises the following steps:
providing a granular positive electrode lithium supplement material;
and carrying out thermal reaction treatment on the positive electrode lithium supplement material in a carbon dioxide atmosphere, and generating a lithium carbonate coating layer on the surface of at least the positive electrode lithium supplement material to obtain the composite positive electrode lithium supplement additive.
9. The method for preparing a catalyst according to claim 8, wherein the temperature of the thermal reaction treatment is 250 to 300 ℃; and/or
The carbon dioxide atmosphere is that carbon dioxide is led into the thermal reaction treatment environment at a certain flow rate and surrounds the positive electrode lithium supplement material; and/or
The positive electrode lithium supplement material is formed by sintering a precursor containing carbonate and collecting CO generated in the sintering process 2 A gas; when the temperature of the anode lithium supplement material to be generated is reduced to the thermal reaction treatment, the collected CO is 2 And introducing gas into the environment where the positive electrode lithium supplement material is located to form the carbon dioxide atmosphere, and performing the thermal reaction treatment.
10. A positive electrode comprises a current collector and a positive active layer combined on the surface of the current collector, and is characterized in that: the positive electrode active layer is doped with the composite positive electrode lithium supplement additive according to any one of claims 1 to 7 or the composite positive electrode lithium supplement additive prepared by the preparation method according to any one of claims 8 to 9.
11. The positive electrode according to claim 10, wherein the composite positive electrode lithium supplement additive is contained in the positive electrode active layer in an amount of 0.1 to 15wt%.
12. A secondary battery comprises a positive plate and a negative plate, and is characterized in that: the positive electrode sheet is the positive electrode according to any one of claims 10 to 11.
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