CN116845195A - Carbon-coated positive electrode material, preparation method thereof and lithium ion battery - Google Patents
Carbon-coated positive electrode material, preparation method thereof and lithium ion battery Download PDFInfo
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- CN116845195A CN116845195A CN202310789705.5A CN202310789705A CN116845195A CN 116845195 A CN116845195 A CN 116845195A CN 202310789705 A CN202310789705 A CN 202310789705A CN 116845195 A CN116845195 A CN 116845195A
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- Prior art keywords
- carbon
- equal
- positive electrode
- electrode material
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 290
- 229910052799 carbon Inorganic materials 0.000 title claims abstract description 278
- 239000007774 positive electrode material Substances 0.000 title claims abstract description 243
- 238000002360 preparation method Methods 0.000 title claims abstract description 39
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims abstract description 17
- 229910001416 lithium ion Inorganic materials 0.000 title claims abstract description 17
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims abstract description 185
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 119
- 238000000576 coating method Methods 0.000 claims abstract description 114
- 239000011248 coating agent Substances 0.000 claims abstract description 103
- 239000010410 layer Substances 0.000 claims abstract description 92
- 239000003575 carbonaceous material Substances 0.000 claims abstract description 44
- 239000010405 anode material Substances 0.000 claims abstract description 24
- 239000002344 surface layer Substances 0.000 claims abstract description 11
- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 6
- 239000000463 material Substances 0.000 claims description 82
- 238000000034 method Methods 0.000 claims description 55
- 239000002245 particle Substances 0.000 claims description 52
- 239000010406 cathode material Substances 0.000 claims description 41
- 238000005245 sintering Methods 0.000 claims description 39
- 239000013078 crystal Substances 0.000 claims description 30
- 239000002243 precursor Substances 0.000 claims description 30
- 239000000203 mixture Substances 0.000 claims description 23
- 238000002156 mixing Methods 0.000 claims description 22
- 230000008569 process Effects 0.000 claims description 21
- 239000007790 solid phase Substances 0.000 claims description 21
- 239000012298 atmosphere Substances 0.000 claims description 20
- 230000014759 maintenance of location Effects 0.000 claims description 18
- 229910052796 boron Inorganic materials 0.000 claims description 16
- 238000012360 testing method Methods 0.000 claims description 14
- 229910003002 lithium salt Inorganic materials 0.000 claims description 13
- 159000000002 lithium salts Chemical class 0.000 claims description 13
- 238000007580 dry-mixing Methods 0.000 claims description 12
- 238000007873 sieving Methods 0.000 claims description 12
- 229910017052 cobalt Inorganic materials 0.000 claims description 11
- 239000010941 cobalt Substances 0.000 claims description 11
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 11
- 238000004519 manufacturing process Methods 0.000 claims description 11
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 10
- 239000011247 coating layer Substances 0.000 claims description 10
- 238000005056 compaction Methods 0.000 claims description 10
- 229910052751 metal Inorganic materials 0.000 claims description 10
- 239000002184 metal Substances 0.000 claims description 10
- 229910052757 nitrogen Inorganic materials 0.000 claims description 10
- 239000001301 oxygen Substances 0.000 claims description 10
- 229910052760 oxygen Inorganic materials 0.000 claims description 10
- 230000007704 transition Effects 0.000 claims description 10
- 229910052727 yttrium Inorganic materials 0.000 claims description 10
- 238000010438 heat treatment Methods 0.000 claims description 9
- 238000011049 filling Methods 0.000 claims description 8
- 150000002222 fluorine compounds Chemical class 0.000 claims description 8
- 229910052698 phosphorus Inorganic materials 0.000 claims description 8
- 150000003568 thioethers Chemical class 0.000 claims description 8
- 229910021393 carbon nanotube Inorganic materials 0.000 claims description 7
- 239000002041 carbon nanotube Substances 0.000 claims description 7
- 239000011164 primary particle Substances 0.000 claims description 7
- 229910052748 manganese Inorganic materials 0.000 claims description 6
- 239000002345 surface coating layer Substances 0.000 claims description 6
- 238000005303 weighing Methods 0.000 claims description 6
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 5
- 230000001590 oxidative effect Effects 0.000 claims description 4
- 238000010998 test method Methods 0.000 claims description 3
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 claims description 2
- 239000006230 acetylene black Substances 0.000 claims description 2
- 229910021383 artificial graphite Inorganic materials 0.000 claims description 2
- 239000002134 carbon nanofiber Substances 0.000 claims description 2
- 239000006232 furnace black Substances 0.000 claims description 2
- 239000010439 graphite Substances 0.000 claims description 2
- 229910002804 graphite Inorganic materials 0.000 claims description 2
- 229910021385 hard carbon Inorganic materials 0.000 claims description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 claims description 2
- 239000003273 ketjen black Substances 0.000 claims description 2
- 230000000630 rising effect Effects 0.000 claims description 2
- 229910021384 soft carbon Inorganic materials 0.000 claims description 2
- 239000003792 electrolyte Substances 0.000 abstract description 14
- 230000003647 oxidation Effects 0.000 abstract description 3
- 238000007254 oxidation reaction Methods 0.000 abstract description 3
- 239000011162 core material Substances 0.000 description 75
- 230000000052 comparative effect Effects 0.000 description 22
- 238000000498 ball milling Methods 0.000 description 19
- 230000000704 physical effect Effects 0.000 description 17
- 239000000243 solution Substances 0.000 description 16
- 239000000843 powder Substances 0.000 description 13
- 238000006243 chemical reaction Methods 0.000 description 10
- 239000008139 complexing agent Substances 0.000 description 10
- 239000000758 substrate Substances 0.000 description 10
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 9
- 239000011572 manganese Substances 0.000 description 9
- 239000011324 bead Substances 0.000 description 8
- 239000012716 precipitator Substances 0.000 description 7
- 239000012266 salt solution Substances 0.000 description 7
- 238000000975 co-precipitation Methods 0.000 description 6
- 238000001035 drying Methods 0.000 description 6
- 238000005406 washing Methods 0.000 description 6
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 description 5
- 230000001276 controlling effect Effects 0.000 description 5
- 230000007797 corrosion Effects 0.000 description 5
- 238000005260 corrosion Methods 0.000 description 5
- 238000001914 filtration Methods 0.000 description 5
- 239000007788 liquid Substances 0.000 description 5
- 238000005070 sampling Methods 0.000 description 5
- 238000001878 scanning electron micrograph Methods 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 4
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 4
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 4
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 4
- 239000002585 base Substances 0.000 description 4
- 150000001875 compounds Chemical class 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 229910052744 lithium Inorganic materials 0.000 description 4
- 238000012216 screening Methods 0.000 description 4
- 238000001179 sorption measurement Methods 0.000 description 4
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 3
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 3
- 235000011114 ammonium hydroxide Nutrition 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 229910000361 cobalt sulfate Inorganic materials 0.000 description 3
- 229940044175 cobalt sulfate Drugs 0.000 description 3
- KTVIXTQDYHMGHF-UHFFFAOYSA-L cobalt(2+) sulfate Chemical compound [Co+2].[O-]S([O-])(=O)=O KTVIXTQDYHMGHF-UHFFFAOYSA-L 0.000 description 3
- 239000002131 composite material Substances 0.000 description 3
- 238000001514 detection method Methods 0.000 description 3
- 229940099596 manganese sulfate Drugs 0.000 description 3
- 239000011702 manganese sulphate Substances 0.000 description 3
- 235000007079 manganese sulphate Nutrition 0.000 description 3
- SQQMAOCOWKFBNP-UHFFFAOYSA-L manganese(II) sulfate Chemical compound [Mn+2].[O-]S([O-])(=O)=O SQQMAOCOWKFBNP-UHFFFAOYSA-L 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 229910044991 metal oxide Inorganic materials 0.000 description 3
- 239000011268 mixed slurry Substances 0.000 description 3
- LGQLOGILCSXPEA-UHFFFAOYSA-L nickel sulfate Chemical compound [Ni+2].[O-]S([O-])(=O)=O LGQLOGILCSXPEA-UHFFFAOYSA-L 0.000 description 3
- 229910000363 nickel(II) sulfate Inorganic materials 0.000 description 3
- 238000006722 reduction reaction Methods 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- 238000003786 synthesis reaction Methods 0.000 description 3
- 229910001428 transition metal ion Inorganic materials 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 229910019142 PO4 Inorganic materials 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- 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 2
- 239000003513 alkali Substances 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 239000001569 carbon dioxide Substances 0.000 description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 description 2
- 229910010293 ceramic material Inorganic materials 0.000 description 2
- 238000005253 cladding Methods 0.000 description 2
- 150000001868 cobalt Chemical class 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000007599 discharging Methods 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 238000000227 grinding Methods 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 238000002955 isolation Methods 0.000 description 2
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 2
- IIPYXGDZVMZOAP-UHFFFAOYSA-N lithium nitrate Chemical compound [Li+].[O-][N+]([O-])=O IIPYXGDZVMZOAP-UHFFFAOYSA-N 0.000 description 2
- 150000002696 manganese Chemical class 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- YQCIWBXEVYWRCW-UHFFFAOYSA-N methane;sulfane Chemical compound C.S YQCIWBXEVYWRCW-UHFFFAOYSA-N 0.000 description 2
- 150000002815 nickel Chemical class 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 2
- 239000010452 phosphate Substances 0.000 description 2
- 238000004321 preservation Methods 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 238000007790 scraping Methods 0.000 description 2
- 238000010532 solid phase synthesis reaction Methods 0.000 description 2
- 229910052721 tungsten Inorganic materials 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- PAWQVTBBRAZDMG-UHFFFAOYSA-N 2-(3-bromo-2-fluorophenyl)acetic acid Chemical compound OC(=O)CC1=CC=CC(Br)=C1F PAWQVTBBRAZDMG-UHFFFAOYSA-N 0.000 description 1
- OAVRWNUUOUXDFH-UHFFFAOYSA-H 2-hydroxypropane-1,2,3-tricarboxylate;manganese(2+) Chemical compound [Mn+2].[Mn+2].[Mn+2].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O.[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O OAVRWNUUOUXDFH-UHFFFAOYSA-H 0.000 description 1
- UPPLJLAHMKABPR-UHFFFAOYSA-H 2-hydroxypropane-1,2,3-tricarboxylate;nickel(2+) Chemical compound [Ni+2].[Ni+2].[Ni+2].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O.[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O UPPLJLAHMKABPR-UHFFFAOYSA-H 0.000 description 1
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- ZGTMUACCHSMWAC-UHFFFAOYSA-L EDTA disodium salt (anhydrous) Chemical compound [Na+].[Na+].OC(=O)CN(CC([O-])=O)CCN(CC(O)=O)CC([O-])=O ZGTMUACCHSMWAC-UHFFFAOYSA-L 0.000 description 1
- 229910013716 LiNi Inorganic materials 0.000 description 1
- 229910021380 Manganese Chloride Inorganic materials 0.000 description 1
- GLFNIEUTAYBVOC-UHFFFAOYSA-L Manganese chloride Chemical compound Cl[Mn]Cl GLFNIEUTAYBVOC-UHFFFAOYSA-L 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- 229910017698 Ni 1-x-y Co Inorganic materials 0.000 description 1
- 229910021586 Nickel(II) chloride Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- MQRWBMAEBQOWAF-UHFFFAOYSA-N acetic acid;nickel Chemical compound [Ni].CC(O)=O.CC(O)=O MQRWBMAEBQOWAF-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000008186 active pharmaceutical agent Substances 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 150000001336 alkenes Chemical class 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- KHPLPBHMTCTCHA-UHFFFAOYSA-N ammonium chlorate Chemical compound N.OCl(=O)=O KHPLPBHMTCTCHA-UHFFFAOYSA-N 0.000 description 1
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 description 1
- 229910052921 ammonium sulfate Inorganic materials 0.000 description 1
- 235000011130 ammonium sulphate Nutrition 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- CREMABGTGYGIQB-UHFFFAOYSA-N carbon carbon Chemical compound C.C CREMABGTGYGIQB-UHFFFAOYSA-N 0.000 description 1
- 239000011203 carbon fibre reinforced carbon Substances 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 238000005119 centrifugation Methods 0.000 description 1
- 150000001860 citric acid derivatives Chemical class 0.000 description 1
- 229940011182 cobalt acetate Drugs 0.000 description 1
- GVPFVAHMJGGAJG-UHFFFAOYSA-L cobalt dichloride Chemical compound [Cl-].[Cl-].[Co+2] GVPFVAHMJGGAJG-UHFFFAOYSA-L 0.000 description 1
- UFMZWBIQTDUYBN-UHFFFAOYSA-N cobalt dinitrate Chemical compound [Co+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O UFMZWBIQTDUYBN-UHFFFAOYSA-N 0.000 description 1
- 229910001981 cobalt nitrate Inorganic materials 0.000 description 1
- MULYSYXKGICWJF-UHFFFAOYSA-L cobalt(2+);oxalate Chemical compound [Co+2].[O-]C(=O)C([O-])=O MULYSYXKGICWJF-UHFFFAOYSA-L 0.000 description 1
- SCNCIXKLOBXDQB-UHFFFAOYSA-K cobalt(3+);2-hydroxypropane-1,2,3-tricarboxylate Chemical compound [Co+3].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O SCNCIXKLOBXDQB-UHFFFAOYSA-K 0.000 description 1
- QAHREYKOYSIQPH-UHFFFAOYSA-L cobalt(II) acetate Chemical compound [Co+2].CC([O-])=O.CC([O-])=O QAHREYKOYSIQPH-UHFFFAOYSA-L 0.000 description 1
- 239000006258 conductive agent Substances 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- -1 for example Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000007429 general method Methods 0.000 description 1
- 239000011521 glass Substances 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
- 238000000875 high-speed ball milling Methods 0.000 description 1
- 238000007602 hot air drying Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 238000007603 infrared drying Methods 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 150000008040 ionic compounds Chemical class 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 230000031700 light absorption 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
- FUJCRWPEOMXPAD-UHFFFAOYSA-N lithium oxide Chemical compound [Li+].[Li+].[O-2] FUJCRWPEOMXPAD-UHFFFAOYSA-N 0.000 description 1
- 229910001947 lithium oxide Inorganic materials 0.000 description 1
- 229940071125 manganese acetate Drugs 0.000 description 1
- 239000011565 manganese chloride Substances 0.000 description 1
- 235000002867 manganese chloride Nutrition 0.000 description 1
- 229940099607 manganese chloride Drugs 0.000 description 1
- 239000011564 manganese citrate Substances 0.000 description 1
- 235000014872 manganese citrate Nutrition 0.000 description 1
- 229940097206 manganese citrate Drugs 0.000 description 1
- UOGMEBQRZBEZQT-UHFFFAOYSA-L manganese(2+);diacetate Chemical compound [Mn+2].CC([O-])=O.CC([O-])=O UOGMEBQRZBEZQT-UHFFFAOYSA-L 0.000 description 1
- MIVBAHRSNUNMPP-UHFFFAOYSA-N manganese(2+);dinitrate Chemical compound [Mn+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O MIVBAHRSNUNMPP-UHFFFAOYSA-N 0.000 description 1
- RGVLTEMOWXGQOS-UHFFFAOYSA-L manganese(2+);oxalate Chemical compound [Mn+2].[O-]C(=O)C([O-])=O RGVLTEMOWXGQOS-UHFFFAOYSA-L 0.000 description 1
- 230000003446 memory effect Effects 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 229910052754 neon Inorganic materials 0.000 description 1
- GKAOGPIIYCISHV-UHFFFAOYSA-N neon atom Chemical compound [Ne] GKAOGPIIYCISHV-UHFFFAOYSA-N 0.000 description 1
- 229940078494 nickel acetate Drugs 0.000 description 1
- QMMRZOWCJAIUJA-UHFFFAOYSA-L nickel dichloride Chemical compound Cl[Ni]Cl QMMRZOWCJAIUJA-UHFFFAOYSA-L 0.000 description 1
- DOLZKNFSRCEOFV-UHFFFAOYSA-L nickel(2+);oxalate Chemical compound [Ni+2].[O-]C(=O)C([O-])=O DOLZKNFSRCEOFV-UHFFFAOYSA-L 0.000 description 1
- KBJMLQFLOWQJNF-UHFFFAOYSA-N nickel(ii) nitrate Chemical compound [Ni+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O KBJMLQFLOWQJNF-UHFFFAOYSA-N 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- QGLKJKCYBOYXKC-UHFFFAOYSA-N nonaoxidotritungsten Chemical compound O=[W]1(=O)O[W](=O)(=O)O[W](=O)(=O)O1 QGLKJKCYBOYXKC-UHFFFAOYSA-N 0.000 description 1
- 238000010606 normalization Methods 0.000 description 1
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000007780 powder milling Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000000967 suction filtration Methods 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 229910001930 tungsten oxide Inorganic materials 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- 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
- 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
- H01M4/48—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
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Composite Materials (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Inorganic Chemistry (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
The invention relates to the technical field of lithium ion batteries, in particular to a carbon-coated positive electrode material, a preparation method thereof and a lithium ion battery. The carbon-coated positive electrode material includes: the high-nickel anode comprises an inner core and a carbon layer, wherein the inner core is made of a high-nickel anode material, and the carbon layer contains a carbon material; wherein the carbon layer is physically adsorbed on the surface layer of the inner core, the roughness delta of the inner core is 0.1-0.45, the definition of the roughness delta is shown as a formula I,in the formula I, V b For the specific surface area BET, m of the inner core 2 /g；W a G/cm, the apparent density of the core 3 . The carbon-coated positive electrode material is prepared by the following steps ofThe carbon coating avoids the direct contact between the anode material and the electrolyte, reduces the oxidation of the anode material to the electrolyte in a charged state, and improves the rate capability and the cycle performance of the carbon coating anode material.
Description
Technical Field
The invention relates to the technical field of lithium ion batteries, in particular to a carbon-coated positive electrode material, a preparation method of the carbon-coated positive electrode material and a lithium ion battery containing the carbon-coated positive electrode material.
Background
The lithium ion battery is a green secondary battery and has the outstanding advantages of high voltage, high energy density, good cycle performance, small self-discharge, no memory effect and the like. Since the success of development in the 90 s of the 20 th century, the application range of lithium ion batteries has been expanding in recent years, including energy storage power systems of power, water power, fire power, wind power and solar power stations, and various fields of electric tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace and the like.
The cost of the positive electrode material accounts for about 40% of the total cost of the lithium ion battery, and the performance of the positive electrode material plays a decisive role for the lithium ion battery. The positive electrode material is generally prepared by mixing a precursor, a lithium source and an additive, then sintering the mixture once, crushing, sieving and removing iron to prepare the primary sintering material. However, the positive electrode material prepared by the process has the problems of poor cycle life, poor storage performance, low capacity and the like. Therefore, the industry tends to carry out ionic compound coating on the primary sintering material and then carrying out secondary sintering, and the surface treatment on the particles improves the interface stability of the material, so that the material with more excellent performance is prepared. With the rapid development of new energy industry, conventional nickel-containing multi-element positive electrode materials cannot meet further requirements of consumers, and high-nickel or ultra-high-nickel positive electrode materials become the main stream of the market due to the advantages of high capacity and low cost, and the adoption of a coating means to optimize the high-nickel or ultra-high-nickel multi-element positive electrode materials is also a current research hot spot.
The carbon material has excellent properties such as corrosion resistance, acid and alkali resistance, good conductive property and the like, and can improve the multiplying power performance, the cycle performance, the energy density and the chemical stability of the material through carbon coating, for example, lithium iron phosphate is an insulator, and an excellent anode material is formed after a layer of conductive carbon is coated, so the carbon coating is a common anode material performance improving means. However, carbon has reducibility and can be coated under inert atmosphere, and because the traditional carbon coating method is that after the positive electrode material is formed, the carbon is coated on the surface of the positive electrode material through low-temperature heat treatment, the method can lead the positive electrode material to be partially reduced in the process of forming a carbon layer, thereby destroying the original structure of the high-nickel positive electrode material, has less influence on lithium cobaltate, lithium iron phosphate, low-nickel materials and the like, but has larger activity on the basis of the material of the high-nickel and ultrahigh-nickel positive electrode material, so that the surface of the high-nickel and ultrahigh-nickel positive electrode material is easy to form residual alkali conversion if the coating is not carried out under inert atmosphere, and Li is led to 2 CO 3 The content increases, which affects the capacity exertion of the material; in addition, a precursor of the cathode material, a lithium source, and a carbon material as a coating agent are directly formed into a cathode material having a carbon-carbon layer by high-temperature solid-phase synthesis, but solid-phase synthesis of high-nickel and ultra-high-nickel cathode materials is generally performed under a high oxygen partial pressure atmosphere, and the carbon material is easily gasified under a high-temperature high oxygen partial pressure condition.
CN111092202A discloses a high-nickel ternary positive electrode material and a preparation method thereof, wherein the substrate material is nickel cobalt lithium manganate, the surface of the nickel cobalt lithium manganate is provided with two coating layers, and LiNi is sequentially arranged from inside to outside x Co y M 1-x-y PO 4 And a carbon layer, the method of making comprising: taking a precursor to react with a phosphoric acid solution to prepare a phosphate coated high-nickel ternary anode material; the phosphate-coated high-nickel ternary cathode material is subjected to catalytic action of transition metal ions and olefin to prepare a carbon layer, and the rate performance and the cycle performance of the obtained cathode material are improved. However, the process is complex, and the industrialized mass production is difficult to realize.
CN108390022a discloses a ternary positive electrode material of a lithium battery with a carbon-metal oxide composite coating, which comprises a ternary positive electrode material matrix, wherein the composite coating comprises a carbon-metal oxide composite, the respective advantages of the carbon coating and the metal oxide are comprehensively utilized, the electronic conductivity and the ion diffusion coefficient of the material are effectively improved, meanwhile, the corrosion of electrolyte to the positive electrode material is effectively prevented, the structure of the material is stabilized, and the electronic conductivity, the multiplying power performance and the cycle performance of the material are improved. However, the preparation process requires sintering at 300-800 ℃ in an inert atmosphere, which is disadvantageous in the preparation of Yu Gaonie carbon-coated materials.
CN108199013a discloses a carbon-coated ternary material and a preparation method thereof, which combines a positive electrode material with a carbon material in a multiple ball milling manner to form the carbon-coated ternary material. However, the method carries out carbon coating in a mode of multiple ball milling, so that the coating strength is weaker, and the improvement range of the electrical property is smaller. In addition, the carbon-coated material is prepared in a multi-ball milling mode, and the preparation process is low in efficiency due to the complexity of the process.
In summary, the preparation of the high-nickel and ultrahigh-nickel carbon coated cathode material by a simple, feasible and efficient carbon coating process on the basis of maintaining the original performance of the material is a problem to be solved at present.
Disclosure of Invention
The invention aims to overcome the technical problems, and provides a novel carbon-coated positive electrode material, a preparation method thereof and a lithium ion battery.
In order to achieve the above object, a first aspect of the present invention provides a carbon-coated positive electrode material comprising: the high-nickel anode comprises an inner core and a carbon layer, wherein the inner core is made of a high-nickel anode material, and the carbon layer contains a carbon material;
Wherein the carbon layer is physically adsorbed on the surface layer of the inner core, the roughness delta of the inner core is 0.1-0.45, the definition of the roughness delta is shown as a formula I,in the formula I, V b For the specific surface area BET, m of the inner core 2 /g；W a G/cm, the apparent density of the core 3 。
In the invention, the roughness delta is a custom dimensionless parameter; in comparison, only numerical comparison is performed.
Preferably, the carbon-coated positive electrode material has a coating layer retention delta of 99% or more, wherein delta=c 0 /C 1 ；
wherein ,C0 Carbon content of the carbon-coated positive electrode material, wt%; c (C) 1 The carbon content of the upper layer material after the carbon-coated positive electrode material is subjected to vibration treatment is wt%; c (C) 1 The test method comprises the steps of taking 200g of the carbon-coated positive electrode material for vibration treatment, wherein the amplitude of the vibration treatment is 3mm, the frequency is 250 times/min, and the time is 60min; and then weighing 1g of upper layer material on the surface layer of the carbon-coated positive electrode material subjected to vibration treatment, and measuring the carbon content of the upper layer material in weight percent.
Preferably, the carbon-coated positive electrode material is prepared by solid phase dry coating.
Preferably, the high nickel positive electrode material has a composition represented by formula II,
wherein ,Lin Ni 1-x-y-a-b Co x M y E a G b O 2 (II)，
Wherein n is more than or equal to 0.9 and less than or equal to 1.5, x is more than or equal to 0 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 1, a is more than or equal to 0 and less than or equal to 0.1, b is more than or equal to 0 and less than or equal to 0+y+a+b is less than or equal to 1, M is Mn and/or Al, and E is selected from at least one of P, N, B, ti, zr, Y, al, mg elements; g is a surface coating layer selected from oxides, sulfides and fluorides containing at least one of B, al and transition elements.
Preferably, the carbon-coated positive electrode material satisfies: z is more than or equal to 1.1 and less than or equal to 2.5, and preferably satisfies the following conditions: z is more than or equal to 1.16 and less than or equal to 2.3; wherein, wherein ,PDc 、AD c and TDc Respectively representing the compaction density, the apparent density and the tap density of the carbon-coated positive electrode material, wherein the units are g/cm 3 ；PD x 、AD x and TDx The compaction density, the apparent density and the tap density of the inner core are respectively expressed in g/cm 3 。
Preferably, the carbon-coated positive electrode material further satisfies formula III:
the second aspect of the present invention provides a method for preparing a carbon-coated cathode material, the method comprising:
in a non-oxidizing atmosphere, carrying out solid-phase dry coating on the mixed material, controlling the filling rate of a device treatment cavity to be 30-65%, and obtaining a carbon-coated positive electrode material comprising an inner core and a carbon layer;
wherein the mixed material comprises a carbon material and a high nickel anode material serving as the inner core;
wherein the solid phase dry coating process comprises a first mixed coating, a second mixed coating and a third mixed coating; the rotating speed of the first mixed coating is less than that of the second mixed coating and less than that of the third mixed coating, and the time of the first mixed coating is less than that of the second mixed coating and less than or equal to that of the third mixed coating.
Preferably, the high nickel positive electrode material has a composition represented by formula II, li n Ni 1-x-y-a-b Co x M y E a G b O 2 (II), wherein n is more than or equal to 0.9 and less than or equal to 1.5, x is more than or equal to 0 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 1, a is more than or equal to 0 and less than or equal to 0.1, b is more than or equal to 0 and less than or equal to x+y+a+b is less than or equal to 1, M is selected from Mn and/or Al, and E is selected from at least one of P, N, B, ti, zr, Y, al, mg elements; g is a surface coating layer selected from oxides, sulfides and fluorides containing at least one of B, al and transition elements.
A third aspect of the present invention provides a lithium ion battery comprising: the carbon-coated positive electrode material provided in the first aspect, or the carbon-coated positive electrode material prepared by the preparation method provided in the third aspect.
Compared with the prior art, the invention has the following advantages:
(1) The carbon-coated positive electrode material provided by the invention comprises the high-nickel positive electrode material serving as the inner core and the carbon layer, wherein the carbon layer is combined with the surface layer of the high-nickel positive electrode material through physical adsorption, and the roughness delta of the inner core is 0.1-0.45, so that the carbon layer and the inner core can be tightly combined, the original electric balance state of the inner core material is effectively maintained, the carbon-coated positive electrode material has good electronic conductivity, the high-nickel positive electrode material is prevented from being in direct contact with electrolyte, the dissolution of transition metal ions is reduced, the side reaction of the positive electrode material and the electrolyte in a charged state is reduced, the corrosion of hydrofluoric acid and the like generated by the decomposition of lithium salt in the electrolyte to the positive electrode is reduced, the electric conductivity of the electrode is improved, and the capacity and the multiplying power performance of the carbon-coated positive electrode material are further improved;
(2) According to the carbon-coated positive electrode material, the carbon material is introduced in a surface coating mode before the battery is manufactured, and particularly, the high-nickel positive electrode material with specific roughness is combined, and the carbon material is dispersed more uniformly on the surface of the inner core through coating strength gradient design, so that the Z value of the carbon-coated positive electrode material is in an optimal range, and the comprehensive performance of the positive electrode material is improved; meanwhile, the addition of carbon materials in the subsequent battery manufacturing process is reduced, and the battery manufacturing efficiency is improved;
(3) The carbon-coated positive electrode material provided by the invention adopts solid-phase dry coating, and particularly realizes high-strength coating of the carbon material and the inner core through specific solid-phase dry coating, so that the carbon material and the inner core are tightly combined to form the carbon-coated positive electrode material; meanwhile, the method avoids the heat treatment process under the atmosphere of low oxygen partial pressure, prevents the inner core from being partially reduced, and avoids the damage of electrochemical performance caused by the partial reduction;
(4) The preparation method provided by the invention belongs to a solid-phase dry coating process, does not involve wet treatment, and has less environmental pollution; meanwhile, the preparation method has the advantages of simplified process flow, simplicity, easiness in operation and higher efficiency, and is suitable for large-scale industrialized application;
(5) The carbon-coated positive electrode material provided by the invention is used in a lithium ion battery, and has high corrosion resistance to electrolyte due to the chemically-stable carbon layer coated on the surface, so that the positive electrode material is prevented from being in direct contact with the electrolyte, the oxidation of the positive electrode material to the electrolyte in a charged state is slowed down, and the good cycle performance of the battery is ensured.
Drawings
FIG. 1 is an SEM image of an agglomerated carbon coated positive electrode material S1 prepared in example 1;
FIG. 2 is an SEM image of a single-crystal type carbon-coated positive electrode material S5 prepared in example 5;
FIG. 3 is an SEM image of an agglomerated carbon coated positive electrode material DS3 prepared in comparative example 3;
FIG. 4 is a graph of 1C/1C cycles at 45℃and 3-4.3V for button cells assembled from the agglomerated carbon coated positive electrode materials of examples 1-3 and comparative example 1, respectively;
fig. 5 is a 1C/1C cycle graph at 45 ℃ and 3-4.3V for button cells assembled from single crystal type carbon coated cathode materials of example 5 and comparative example 2, respectively.
Detailed Description
The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.
In the present invention, unless specifically stated otherwise, the terms "first," "second," and "third" do not denote a sequential order, nor are they intended to be limiting of the various materials or steps, but are merely used to describe that they are not the same materials or steps. For example, "first", "second", and "third" among "first", "second", and "third hybrid cladding" are merely used to illustrate that this is not the same hybrid cladding.
The first aspect of the present invention provides a carbon-coated positive electrode material comprising: the high-nickel anode comprises an inner core and a carbon layer, wherein the inner core is made of a high-nickel anode material, and the carbon layer contains a carbon material;
wherein the carbon layer is physically adsorbed on the surface layer of the inner core, the roughness delta of the inner core is 0.1-0.45, the definition of the roughness delta is shown as a formula I,in the formula I, V b For the specific surface area BET, m of the inner core 2 /g；W a G/cm, the apparent density of the core 3 。
The inventors of the present invention studied and found that: because the carbon material has ultrahigh conductivity, when the carbon material and the high-nickel positive electrode material are physically adsorbed and the roughness delta of the inner core of the self-defined coating layer retention rate is 0.1-0.45, the heat treatment process under the atmosphere of low oxygen partial pressure can be avoided, the positive electrode material is prevented from being partially reduced, the electrochemical performance damage caused by the heat treatment process is avoided, the carbon material can be distributed on the pores and the surface of the inner core (high-nickel positive electrode material), the carbon material and the inner core material are tightly combined, and the situation that the carbon layer falls off powder in the practical application process is prevented; meanwhile, the original electric balance state of the core material can be effectively changed through carbon coating, so that the carbon-coated positive electrode material has good electronic conductivity, the carbon layer can prevent the positive electrode material from being in direct contact with electrolyte, the dissolution of transition metal ions is reduced, the oxidation of the positive electrode material to the electrolyte in a charged state is slowed down, the corrosion of hydrofluoric acid and the like generated by the decomposition of lithium salt in the electrolyte to the positive electrode is reduced, the electric conductivity of the electrode is improved, and the capacity and the multiplying power performance of the carbon-coated positive electrode material are further improved.
In the present invention, it is preferable that the carbon-coated positive electrode material has a coating layer retention δ of 99% or more, for example, 99%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, and any value in the range of any two values, wherein δ=c 0 /C 1 ；C 0 Carbon content of the carbon-coated positive electrode material, wt%; c (C) 1 The carbon content of the upper layer material after the carbon-coated positive electrode material is subjected to vibration treatment is wt%; c (C) 1 The test method comprises the steps of taking 200g of the carbon-coated positive electrode material for vibration treatment, wherein the amplitude of the vibration treatment is 3mm, the frequency is 250 times/min, and the time is 60min; then weighing 1g of upper material on the surface layer of the carbon-coated positive electrode material after vibration treatment, and measuring the carbon content of the upper material in weight percent; further preferably, the carbon-coated positive electrode material has a coating layer retention δ of 99.5 to 99.9%.
In the invention, physical adsorption is carried out between the inner core of the carbon-coated positive electrode material and the carbon layer, the carbon layer does not form reduction reaction on the high-nickel positive electrode material in the coating process, so that the damage to the electrochemical performance of the inner core can be avoided, wherein the carbon layer is tightly combined with the inner core, after vibration treatment, the measured retention rate delta of the coating layer of the carbon-coated positive electrode material is more than or equal to 99%, which indicates that the physical adsorption strength between the carbon layer and the inner core is high, and the obtained carbon-coated positive electrode material is not easy to fall off powder.
In the present invention, the principle of measurement of the coating retention δ is: after the carbon-coated positive electrode material is subjected to certain vibration treatment, if the combination of the carbon layer and the inner core is not tight, a certain amount of carbon layer which falls off can be generated, and the density of the carbon layer is smaller than that of the carbon-coated positive electrode material and the inner core, so that the carbon-coated positive electrode material can be covered on the surface layer after the vibration treatment, and the carbon content C of the carbon-coated positive electrode material which is not subjected to the vibration treatment is detected respectively 0 Carbon content C of the upper material of fixed mass after vibration treatment 1 From C 0 /C 1 Obtaining the carbon-coated positive electrode materialThe coating retention delta of (2). It can be understood that if the carbon layer is not tightly combined with the inner core, the carbon content of the upper material can be increased after the vibration treatment, and the delta value is smaller (less than 99 percent); if the carbon layer is tightly combined with the inner core, the carbon content of the upper layer before and after the vibration treatment is equivalent, and the value of delta is more approximate to 1.
In the invention, the upper material is sampled on the surface layer of the material after vibration treatment, the sampling amount of the upper material is limited to 0.5wt% of the carbon-coated positive electrode material, and the mass ratio of the upper material in the carbon-coated positive electrode material is understood to be not more than the mass ratio of the carbon layer in the carbon-coated positive electrode material, so that more accurate values can be obtained, and C is avoided when the upper material is sampled excessively 1 Is of a value close to C 0 There is a case where the difference between the two is smaller than the measurement error without the significance of the test.
In one embodiment of the invention, exemplary testing steps for the coating retention delta include:
(1) Taking a certain amount of carbon-coated anode material, and adopting a high-frequency infrared carbon-sulfur analyzer to perform carbon content test to obtain the carbon content C of the screen material 0 Wt%; the testing principle of the high-frequency infrared carbon-sulfur analyzer is that a sample is subjected to high-frequency induction heating, so that a carbon layer on the surface of an inner core is converted into carbon dioxide, when infrared light with a certain specific wavelength passes through carbon dioxide gas, strong light absorption can be generated, and the analysis result of the carbon content of the sample to be tested can be obtained after detection, integration and normalization treatment;
(2) Placing the carbon-coated positive electrode material into an appliance, then placing the appliance into a powder tap density meter for vibration, wherein the amplitude is 3mm, the frequency is 250 times/min, after 60min of vibration, weighing 1g of upper material on the surface layer of the carbon-coated positive electrode material subjected to vibration treatment, and measuring the carbon content/% of the upper material to obtain C 1 ；
(3) According to delta=c 0 /C 1 And calculating the value of delta, namely the retention rate of the coating layer.
In the invention, the sampling mode of the upper material is not limited, but the upper material is ensured to be taken from a specified amount of materials from top to bottom in the device after being subjected to vibration treatment;
For example, the required amount of upper layer material can be sequentially obtained layer by layer in a scraping manner, for example, if the material subjected to vibration treatment comprises a first layer, a second layer and a third layer from top to bottom, the upper layer material needs to be preferentially obtained from the first layer, and if the required amount is insufficient, the material is scraped from the surface of the second layer until the sufficient amount of upper layer material is obtained, but the required amount of upper layer material cannot be directly obtained from the first layer to the second layer or even the third layer along the depth direction of the material;
the device with a openable and closable discharging hole at the bottom can also be used, for example, the device can comprise a cylinder with a thread at one end and a base in threaded connection with the thread of the cylinder, when the material is required to be taken, the device is suspended above the weighing device, the base is unscrewed, and the required amount of upper material is obtained by controlling the weight of the material on the weighing device; in the mode, taking 200g of material as an example, the discharging amount is preferably controlled below 1g/s, and it is understood that the larger the length-diameter ratio of the cylinder is, the better the length-diameter ratio is, so that the flow rate is controlled, and the more accurate amount of the remainder, namely the upper material, is obtained under the condition that conditions allow; of course, the volume occupied by the required amount of upper material in the device can be estimated by arranging scales on the cylinder so as to flow out a proper amount of material, and then the required upper material can be obtained by fine adjustment continuously; or the top end of the measuring cylinder is connected with a negative pressure device, and the specified amount of upper material is sucked by adjusting the negative pressure. In the present application, only an exemplary sampling manner is given, and specific sampling steps or forms are not limited, so long as the sampling amount of the upper layer material can be achieved.
In some embodiments of the present invention, preferably, the carbon-coated positive electrode material is prepared by solid phase dry coating. Compared with the prior art, the solid-phase dry coating realizes the physical adsorption of the carbon layer and the inner core, avoids the heat treatment process under the atmosphere of low oxygen partial pressure, prevents the anode material from being partially reduced, and avoids the electrochemical performance damage caused by the partial reduction.
In some embodiments of the present invention, preferably, the high nickel positive electrode material has a composition shown in formula II, wherein Li n Ni 1-x-y-a-b Co x M y E a G b O 2 (II)，
Wherein n is more than or equal to 0.9 and less than or equal to 1.5, x is more than or equal to 0 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 1, a is more than or equal to 0 and less than or equal to 0.1, b is more than or equal to 0 and less than or equal to x+y+a+b is less than or equal to 1, M is selected from Mn and/or Al, and E is selected from at least one of P, N, B, ti, zr, Y, al, mg elements; g is a surface coating layer selected from oxides, sulfides and fluorides containing at least one of B, al and transition elements. In the present invention, the transition elements include, but are not limited to W, ti, sr, Y, zr, nb, V, mo.
In the present invention, unless otherwise specified, in formula II, when a is not equal to 0 and b is not equal to 0, the core formula is Li n Ni 1-x-y-a-b Co x M y E a G b O 2 The method comprises the steps of carrying out a first treatment on the surface of the When a=0 and b+.0, or a+.0 and b=0, the kernel formula is Li n Ni 1-x-y- b Co x M y G b O 2, or ,Lin Ni 1-x-y-a Co x M y E a O 2 The method comprises the steps of carrying out a first treatment on the surface of the When a=0 and b=0, the core formula is Li n Ni 1-x-y Co x M y O 2 。
In some embodiments of the invention, in formula II, 0.9.ltoreq.n.ltoreq.1.5, preferably 0.95.ltoreq.n.ltoreq.1.25; x is more than or equal to 0 and less than or equal to 1, preferably more than or equal to 0.01 and less than or equal to 0.2; y is more than or equal to 0 and less than or equal to 1, preferably more than or equal to 0.01 and less than or equal to 0.1; 0.ltoreq.a.ltoreq.0.1, for example, 0, 0.001, 0.002, 0.003, 0.005, 0.01, 0.02, 0.05, 0.1, and any value in the range of any two values, preferably 0 < a.ltoreq.0.05; 0.ltoreq.b.ltoreq.0.1, e.g.0, 0.001, 0.002, 0.005, 0.01, 0.02, 0.05, 0.1, and any value in the range of any two values, 0 < b.ltoreq.0.05; 0 < x+y+a+b < 1, preferably 0.02 < x+y+a+b.ltoreq.0.4.
In some embodiments of the invention, the roughness delta of the core is any of a range of 0.1 to 0.45, e.g., 0.1, 0.12, 0.15, 0.2, 0.22, 0.25, 0.3, 0.35, 0.38, 0.45, and any two values, preferably 0.12 to 0.38.
In some embodiments of the invention, preferably, theAverage particle diameter D of the inner core 50 Is 2 to 16 μm, for example, any value in the range of 2 μm, 3 μm, 5 μm, 8 μm, 10 μm, 15 μm, 16 μm, and any two values, preferably 3 to 14 μm; BET of 0.1-2m 2 /g, e.g. 0.1m 2 /g、0.2m 2 /g、0.5m 2 /g、0.8m 2 /g、1m 2 /g、1.3m 2 /g、2m 2 Per g, any value in the range of any two values, preferably 0.2-1.3m 2 And/g. The inner core meeting the condition range is more beneficial to improving the coating strength of the inner core and the carbon layer, and further improving the performance of the carbon-coated positive electrode material.
In the present invention, the first sintering condition (e.g., temperature, time, etc.) is controlled so that the inner core satisfies the above parameter definition.
In the present invention, the average particle diameter D is not particularly specified 50 The parameters were measured using a malvern Mastersizer 3000 laser particle size analyzer; the BET parameter of the specific surface area is measured by a microphone ASAP2020 full-automatic specific surface area and a porosity analyzer; bulk density parameters were measured by a powder bulk densitometer.
In some embodiments of the invention, it is further preferred that when the core is selected from agglomerated particles, the roughness delta of the agglomerated particles is any value in the range of 0.1 to 0.35, e.g., 0.1, 0.12, 0.15, 0.2, 0.22, 0.25, 0.3, 0.35, and any two values, preferably 0.12 to 0.25; the average particle diameter D of primary particles in the agglomerated particles 50 300-700nm, for example 300nm, 350nm, 400nm, 500nm, 700nm, and any value in the range of any two values, preferably 350-500nm. In the invention, in the carbon coating process of the agglomerate meeting the conditions, the carbon material fills gaps among primary particles preferentially, and a carbon layer and particles are formed into an 'inter-embedding' structure through gradient coating, so that the bonding strength of the 'carbon layer' and the primary particles is further enhanced.
In some embodiments of the invention, it is further preferred that when the inner core is selected from single crystal particles, the roughness delta of the single crystal particles is 0.15-0.45, e.g. 0.15, 0.2, 0.22, 0.25, 0Any value in the range of 3, 0.35, 0.38, 0.45, and any two values, preferably 0.22-0.38; the average particle diameter D of the single crystal particles 50 Is 0.6 to 3 μm, for example, 0.6 μm, 1 μm, 1.5 μm, 2 μm, 3 μm, and any value in the range of any two values, preferably 1 to 2 μm.
In some embodiments of the invention, the carbon layer preferably has a thickness of 10-200nm, e.g., 10nm, 50nm, 60nm, 70nm, 80nm, 100nm, 150nm, 200nm, and any value in the range of any two values, preferably 50-100nm. In the invention, when the thickness of the carbon layer meets the conditions, the carbon layer is densely coated on the surface of the inner core, so that the original electric balance state of the high-nickel positive electrode material can be effectively changed, the electric conductivity of the electrode is improved, and the capacity and the multiplying power performance of the carbon-coated positive electrode material are further improved.
In the invention, the thickness of the carbon layer is tested as follows: firstly, carrying out ion grinding sample preparation on a carbon-coated anode material, then observing the position conforming to a coating layer by using a scanning electron microscope, and finally determining the thickness of a carbon layer by using energy spectrum scanning; the thickness of the carbon layer is measured by randomly selecting 20 areas along the periphery of a specific particle, and the average value of the areas is defined as the thickness of the carbon layer of the specific particle. In the invention, in order to improve the test accuracy, 40-60 particles are selected for testing each time, and the average value of the carbon layer thickness is the carbon layer thickness of the sample.
In some embodiments of the present invention, it is preferred that the standard deviation of the carbon content test values at any three points in the carbon-coated positive electrode material be 0.005 or less, for example, any of the ranges consisting of 0.0005, 0.001, 0.0015, 0.002, 0.0025, 0.003, 0.005, and any two values, preferably 0.0025 or less. When the conditions are met, the carbon layer of the carbon-coated positive electrode material is good in uniformity, the comprehensive performance of the carbon-coated positive electrode material can be improved, the addition of conductive carbon in the subsequent battery manufacturing process can be reduced, and the battery manufacturing efficiency is improved.
In the invention, the carbon layer meeting the parameter limit is easier to be attached to the inner core, so that the coating strength of the carbon-coated positive electrode material is improved.
In some embodiments of the invention, preferably, the carbon layer is composed of the carbon material.
In some embodiments of the present invention, preferably, the carbon material is selected from at least one of acetylene black, furnace black, ketjen black, carbon nanotubes, carbon nanofibers, graphite particles, porous carbon, soft carbon, hard carbon, and artificial graphite.
In some embodiments of the present invention, preferably, the volume impedance ratio of the carbon-coated positive electrode material to the core is 20 to 70:100, for example, 20:100, 30:100, 40:100, 50:100, 60:100, 70:100, preferably 30-50:100. in the invention, the volume impedance ratio in the range is satisfied, which shows that the carbon layer is densely coated on the surface of the inner core, so that the original electric balance state of the high-nickel positive electrode material can be effectively changed, the electric conductivity of the electrode is improved, and the capacity and the multiplying power performance of the carbon-coated positive electrode material are further improved.
In some embodiments of the present invention, it is preferable that the carbon layer is contained in an amount of 0.1 to 5wt%, for example, 0.1wt%, 0.19wt%, 0.48wt%, 0.96wt%, 0.97wt%, 0.98wt%, 1.47wt%, and any value in a range of any two numerical values, preferably 0.96 to 1.47wt%, based on the total weight of the carbon-coated cathode material. In the invention, the content of the carbon layer is more than 5 weight percent, which not only affects Li in the charge and discharge process of the material + Transmission, which deteriorates dynamics, also deteriorates coating strength, and costs too much; when the carbon layer content is less than 0.1wt%, the coating effect is poor, and the effect of improving the conductivity by carbon coating is hardly exerted.
In some embodiments of the present invention, preferably, the carbon-coated positive electrode material satisfies: 1.1.ltoreq.Z.ltoreq.2.5, e.g.Z is any value selected from the group consisting of 1.1, 1.16, 1.18, 1.2, 1.23, 1.25, 1.3, 1.5, 1.72, 1.8, 2, 2.13, 2.2, 2.3, 2.5, and any two values, preferably satisfying any of the following ranges: z is more than or equal to 1.16 and less than or equal to 2.3; wherein, wherein ,PDc 、AD c and TDc Respectively representing the compaction density, the apparent density and the tap density of the carbon-coated positive electrode material, wherein the units are g/cm 3 ；PD x 、AD x and TDx The compaction density, the apparent density and the tap density of the inner core are respectively expressed in g/cm 3 . In the present invention, the Z value in the above range is satisfied, and the carbon-coated positive electrode material particles are in close contact with each other, the density index is high, and the carbon layer can be closely bonded to the surface of the positive electrode material.
In some embodiments of the present invention, it is further preferred that when the core is selected from an agglomerated high nickel positive electrode material, the positive electrode material satisfies: 1.1.ltoreq.Z.ltoreq.1.3, e.g.Z is any value selected from the group consisting of 1.1, 1.16, 1.18, 1.2, 1.23, 1.25, 1.3, and any two values, preferably satisfying: z is more than or equal to 1.16 and less than or equal to 1.23. The carbon-coated agglomerated cathode material satisfying the above range has excellent capacity and cycle properties.
In some embodiments of the present invention, it is further preferred that when the core is selected from single crystal high nickel cathode materials, the cathode materials satisfy: 1.5.ltoreq.Z.ltoreq.2.5, e.g.Z is any value selected from the group consisting of 1.5, 1.72, 1.8, 2, 2.13, 2.2, 2.3, 2.5, and any two values, preferably satisfying: z is more than or equal to 1.72 and less than or equal to 2.3. The lithium ion battery with the carbon-coated single-crystal positive electrode material structure meeting the range has high capacity serving as a capacitor for the first time and good capacity retention rate.
In some embodiments of the present invention, preferably, the carbon-coated positive electrode material further satisfies formula III:in the invention, the limitation is satisfied, which shows that the carbon layer of the carbon-coated positive electrode material is tightly combined with the inner core, and has smaller surface roughness, namely, the surface of the particle of the inner core coated with the carbon layer is smoother, so that the wettability of the surface of the material and electrolyte can be effectively improved, the contact reaction active area of the electrolyte is increased, and the rate capability is effectively improved.
In the present invention, the density parameter is compactedThe number may be tested by a compaction test system of the powder resistance meter, in particular the MCP-PD51 measurement. Samples were added to the abrasive article and the load was adjusted to 20KN. The pressure is regulated to 20KN by regulating the pressure rod, and a detection report is output, so that the compaction density, g/cm can be read 3 。
In the invention, the bulk density parameter can be measured according to a Si Ke Tesong bulk density meter, and the powder bulk density test is developed according to GB/T1479.2-2011 (determination of bulk density of metal powder-second part: sicote volume metering method). Wherein the volume of the cylindrical cup is S (cm) 3 ). The following modes can be referred to specifically: for the bulk density tested in the test, the cylinder cup was weighed and designated G1. The carbon coated positive electrode material was gently placed on the screen of the upper combining funnel with a scoop, and the material was gently brushed with a small brush (without vibrating the apparatus, especially the cylinder cup) through the screen, through the cloth box, square funnel, and into the cylinder cup until full and powder was spilled. And taking out the cylindrical cup, and scraping the material overflowing the cylindrical cup part with a stainless steel plate ruler. The powder attached to the outer surface of the cup was scraped off by taking out the cup, and the weight G2 of the cylindrical cup and the powder was weighed to an accuracy of 0.01G. The apparent density, g/cm, can then be calculated using the following equation 3 Namely, bulk density= (cylindrical cup and powder weight-cup weight)/cup volume= (G2-G1)/S.
In the invention, the detection of tap density can refer to a general method for measuring the tap density of a GB/T21354-2008 powder product, and the method is a national standard for measuring the tap density. Tap density parameters can be measured in the laboratory by the following method:
a 10mL measuring cylinder (material: glass) was placed on a balance, the balance was calibrated to 0, a carbon-coated positive electrode material was added to the measuring cylinder, the line of sight was adjusted to the height of the carbon nanotubes, and then the scale was read to measure the volume of the carbon nanotubes, and the addition was stopped when the volume was 8-10 mL. The cylinder containing the positive electrode material is then placed on a calibrated balance and weighed, and the weight m (g) is recorded. Vibrating on the ground paved with rubber pad for about 100 times, rotating the measuring cylinder 20 times each time, and controlling the amplitude to be 1-1.5cm. Measuring the volume of carbon nanotubes by reading the scale of a graduated cylinderProduct, recorded as V (mL). Tap density g/cm can be calculated by the following equation 3 I.e. tap density = m/V.
The second aspect of the present invention provides a method for preparing a carbon-coated cathode material, the method comprising:
in a non-oxidizing atmosphere, carrying out solid-phase dry coating on the mixed material, controlling the filling rate of a device treatment cavity to be 30-65%, and obtaining a carbon-coated positive electrode material comprising an inner core and a carbon layer;
Wherein the mixed material comprises a carbon material and a high nickel anode material serving as the inner core;
wherein the solid phase dry coating process comprises a first mixed coating, a second mixed coating and a third mixed coating; the rotating speed of the first mixed coating is less than that of the second mixed coating and less than that of the third mixed coating, and the time of the first mixed coating is less than that of the second mixed coating and less than or equal to that of the third mixed coating.
In the present invention, the non-oxidizing atmosphere includes, but is not limited to, nitrogen, helium, argon, neon, and the like, and is preferably nitrogen, unless otherwise specified.
In the invention, the filling rate of the treatment cavity of the control equipment is 30-65% without special description, which means that the mixed material containing the high-nickel positive electrode material and the carbon material occupies the effective volume ratio of the treatment cavity. The filling rate of material filling is controlled so that the whole system has reasonable compressive stress, and the specific equipment type, material and the like are not greatly influenced. If the filling rate is less than 30% or more than 65%, the coating effect is affected.
In the invention, the solid-phase dry coating equipment comprises, but is not limited to, high-speed mixer equipment, wherein the inner lining of the high-speed mixer is subjected to metal isolation treatment by using ceramic materials, and the high-speed mixer is subjected to physical cooling by introducing chilled water in the coating process.
In the invention, under the condition of no special description, the first mixed coating enables the carbon material to be uniformly dispersed in the particle gaps of the high-nickel positive electrode material; the second mixed coating enables the carbon material to adhere to the particle surfaces of the high-nickel positive electrode material; the third mixed coating realizes the tight combination of the carbon material and the high-nickel positive electrode material.
In some embodiments of the present invention, preferably, the conditions of the first hybrid coating include: the rotating speed is 600-800rpm, and the time is 10-30min; the conditions of the second hybrid coating include: the rotating speed is 70-1000rpm, and the time is 15-60min; the conditions of the third hybrid coating include: the rotating speed is 900-1200rpm, and the time is 20-90min.
In some embodiments of the present invention, it is further preferred that the rotation speed ratio of the first mixed coating, the second mixed coating, and the third mixed coating is 1:1.2-1.3:1.4-1.5; the time ratio of the first mixed coating, the second mixed coating and the third mixed coating is 1:1.5-2:2-3. The coating method meets the range of the conditions, can realize high-strength uniform coating, and can prevent particles from cracking or powdering in the coating process.
In some embodiments of the present invention, preferably, the high nickel positive electrode material has a composition represented by formula II, li n Ni 1-x-y-a-b Co x M y E a G b O 2 (II), wherein n is more than or equal to 0.9 and less than or equal to 1.5, x is more than or equal to 0 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 1, a is more than or equal to 0 and less than or equal to 0.1, b is more than or equal to 0 and less than or equal to x+y+a+b is less than or equal to 1, M is selected from Mn and/or Al, and E is selected from at least one of P, N, B, ti, zr, Y, al, mg elements; g is a surface coating layer selected from oxides, sulfides and fluorides containing at least one of B, al and transition elements.
In some embodiments of the present invention, it is further preferred that in formula II, 0.95.ltoreq.n.ltoreq. 1.25,0.01.ltoreq.x.ltoreq.0.2, 0.01.ltoreq.y.ltoreq.0.1, 0 < a.ltoreq.0.05, 0 < b.ltoreq. 0.05,0.02 < x+y+a+b.ltoreq.0.4.
In some embodiments of the invention, preferably, the mass ratio of the core to the carbon layer is 95-99.9:0.1-5, e.g., 95:5, 97:3, 98:2, 98.53:1.47, 99:1, 99.04:0.96, 99.9:0.1, and any value in the range of any two values, preferably 98.53-99.04:0.96-1.47.
In the present invention, it is not specified that the carbon-coated positive electrode material has a carbon material content lower than the percentage of the core addition amount because the solid phase dry coating causes a loss of a minute amount of carbon material (1 to 5 wt%).
In the invention, the source of the high nickel positive electrode material has a wider selection range, and can be obtained through purchase or preparation. Preferably, the high nickel positive electrode material is prepared by the following method:
S1, carrying out first dry mixing on lithium salt, a positive electrode material precursor and an E source, then carrying out first sintering, and sequentially crushing and sieving the obtained initial product to obtain a base material;
s2, carrying out second dry mixing on the base material and a G source, then carrying out second sintering to obtain a second sintering product, and sequentially crushing and sieving to obtain a high-nickel anode material with a composition shown in a formula II;
wherein the positive electrode material precursor has a composition represented by formula IV: ni (Ni) 1-α-β Co α M β (OH) 2 (IV) alpha is more than or equal to 0 and less than 1, beta is more than or equal to 0 and less than 1, alpha+beta is more than 0 and less than 1, and M is selected from Mn and/or Al.
In some embodiments of the present invention, it is further preferred that in formula IV, 0.01. Ltoreq.α.ltoreq.0.2, 0.01. Ltoreq.β.ltoreq. 0.1,0.02. Ltoreq.α+β.ltoreq.0.3.
In some embodiments of the present invention, preferably, when the inner core is selected from agglomerated high nickel positive electrode materials, the positive electrode material precursor has an average particle diameter D 50 6-14 μm, and specific surface area BET of 4-16m 2 Per gram, bulk density is not less than 1.4g/cm 3 The tap density is more than or equal to 1.8g/cm 3 The method comprises the steps of carrying out a first treatment on the surface of the Alternatively, when the core is selected from single-crystal high-nickel positive electrode materials, the positive electrode material precursor has an average particle diameter D 50 2-6 μm, and specific surface area BET of 4-30m 2 Per gram, bulk density not less than 1g/cm 3 The tap density is more than or equal to 1.4g/cm 3 。
In some embodiments of the present invention, it is preferred that the ratio of the lithium salt, the positive electrode material precursor, and the E source is such that n (Li) n (Ni+Co+M) n (E) =n (Li) 1:n (E), wherein 0.9.ltoreq.n (Li). Ltoreq.1.5, e.g., any of the ranges of 0.9, 0.95, 1, 1.1, 1.2, 1.25, 1.5, and any two values, preferably 0.95.ltoreq.n (Li). Ltoreq.1.25; 0.ltoreq.n (E). Ltoreq.0.1, for example, any value in the range of 0, 0.001, 0.002, 0.003, 0.005, 0.01, 0.02, 0.05, 0.1 and any two values, preferably 0 < n (E). Ltoreq.0.05.
In some embodiments of the invention, the lithium salt is selected from at least one of lithium oxide, lithium hydroxide, lithium carbonate, and lithium nitrate; the E source is selected from oxide, hydroxide and carbonate containing at least one of P, N, B, ti, zr, Y, al, mg elements.
In some embodiments of the present invention, preferably, the conditions of the first dry mix and the second dry mix each independently comprise: the mixing time is 0.5-6h, and the mixing frequency is 30-150Hz.
In some embodiments of the present invention, preferably, the conditions of the first sintering include: the process is carried out in the atmosphere with the oxygen content of 90-99.5 vol%, the temperature is 650-1200 ℃, the temperature rising rate is 2-10 ℃/min, and the constant temperature time is 6-20h.
In some embodiments of the present invention, preferably, in step S1, when the core is selected from an agglomerated high nickel positive electrode material, the temperature T of the first sintering satisfies formula V:
wherein ,CNi Is the mole percent of nickel in the mixture of nickel source, cobalt source and M source, calculated as metal;
alternatively, when the core is selected from single crystal high nickel positive electrode materials, the temperature T of the first sintering satisfies formula VI:
wherein ,CNi Is the mole percent of nickel in the mixture of nickel source, cobalt source and M source, calculated as metal.
In the present invention, the first sintering temperature satisfying the above range gives a roughness of 0.1 to 0.45 and a flatAverage particle diameter D 50 2-16 μm and a specific surface area BET of 0.1-2m 2 High nickel positive electrode material per gram.
In some embodiments of the present invention, preferably, the G source is selected from oxides, sulfides, and fluorides containing at least one of B, al and a transition element; the transition element includes, but is not limited to W, ti, sr, Y, zr, nb, V, mo and the like, and is preferably W.
In some embodiments of the present invention, the G source is preferably used in an amount such that n (G)/(Ni+Co+M+E+G) =n (G)/(G) 1, wherein 0.ltoreq.n (G). Ltoreq.0.1, e.g., any of 0, 0.001, 0.002, 0.005, 0.01, 0.02, 0.05, 0.1, and any range of any two values, preferably 0 < n (G). Ltoreq.0.05.
In some embodiments of the present invention, preferably, the second sintering conditions include: the process is carried out in the atmosphere with the oxygen content of more than or equal to 20 volume percent, the temperature is 300-800 ℃, the heating rate is 2-10 ℃/min, and the constant temperature time is 6-20h.
In one embodiment of the invention, when the core is selected from the group consisting of agglomerated high nickel positive electrode materials, formula I is prepared by:
s1, lithium salt with general formula of Ni 1-α-β Co α M β (OH) 2 Uniformly mixing the positive electrode material precursor and the E source in a first dry mixing mode, and then performing first sintering to obtain a primary product, and sequentially crushing, crushing and sieving to obtain an agglomerated substrate;
wherein the particle diameter D of the positive electrode material precursor 50 6-14 μm, and specific surface area BET of 4-16m 2 Per g, bulk density not less than 1.4g/cm 3 The tap density is more than or equal to 1.8g/cm 3 The method comprises the steps of carrying out a first treatment on the surface of the The mixing time of the first dry mixing is 0.5-6h, and the mixing frequency is 30-150Hz; the temperature T of the first sintering satisfies formula V: wherein ,CNi Is the mole percent of nickel in the mixture of nickel source, cobalt source and M source, calculated as metal;
s2, uniformly mixing the agglomerated base material and the G source in a second dry mixing mode (mixing time is 0.5-6h, mixing frequency is 30-150 Hz), and then performing second sintering to obtain a second sintered product, and sequentially crushing and sieving to obtain the agglomerated high-nickel anode material.
In another embodiment of the invention, when the inner core is selected from single crystal type high nickel positive electrode materials, formula I is prepared by the following method:
s1, lithium salt with general formula of Ni 1-α-β Co α M β (OH) 2 Uniformly mixing the positive electrode material precursor and the E source in a first dry mixing mode, and then performing first sintering to obtain a primary product, and sequentially crushing, crushing and sieving to obtain a single-crystal substrate;
wherein the particle diameter D of the positive electrode material precursor 50 2-6 μm, and specific surface area BET of 4-30m 2 Per gram, bulk density not less than 1g/cm 3 The tap density is more than or equal to 1.4g/cm 3 The method comprises the steps of carrying out a first treatment on the surface of the The mixing time of the first dry mixing is 0.5-6h, and the mixing frequency is 30-150Hz; the temperature T of the first sintering satisfies formula VI: wherein ,CNi Is the mole percent of nickel in the mixture of nickel source, cobalt source and M source, calculated as metal;
s2, uniformly mixing the monocrystalline substrate and a G source in a second dry mixing mode (mixing time is 0.5-6h, mixing frequency is 30-150 Hz), then performing second sintering to obtain a second sintered product, and sequentially crushing and sieving to obtain the monocrystalline high-nickel anode material.
In the present invention, the general formula is Ni 1-α-β Co α M β (OH) 2 The positive electrode material precursor is prepared by adopting a coprecipitation method, and specifically comprises the following steps:
(1) Preparing a mixed salt solution by using a nickel source, a cobalt source and an M source according to the molar ratio of n (Ni): n (Co): n (M) = (1-alpha): alpha:beta; respectively preparing a precipitator solution and a complexing agent solution;
(2) Mixing the mixed salt solution and the precipitantAdding the solution and the complexing agent solution into a reaction kettle, performing coprecipitation reaction in an inert atmosphere, filtering, washing, drying and screening the obtained solid-liquid mixed slurry to obtain a compound with a general formula of Ni 1-α-β Co α M β (OH) 2 Is a positive electrode material precursor.
In some embodiments of the invention, in step (1), the concentration of the mixed salt solution, calculated as metal, is 1 to 3mol/L, preferably 1.5 to 2.5mol/L; the concentration of the precipitant solution is 2-15mol/L, preferably 5-10mol/L; the concentration of the complexing agent solution is 1-15mol/L, preferably 5-10mol/L.
In some embodiments of the invention, in step (1), the nickel source, cobalt source, and M source are each independently selected from at least one of a sulfate, nitrate, chloride, oxalate, acetate, and citrate salt comprising nickel, cobalt, and M; further preferably, the nickel source is selected from at least one of nickel sulfate, nickel nitrate, nickel chloride, nickel oxalate, nickel acetate, and nickel citrate; the cobalt source is at least one selected from cobalt sulfate, cobalt nitrate, cobalt chloride, cobalt oxalate, cobalt acetate and cobalt citrate; the M source is selected from at least one of manganese sulfate, manganese nitrate, manganese chloride, manganese oxalate, manganese acetate and manganese citrate. The precipitants include, but are not limited to, sodium hydroxide and/or potassium hydroxide; the complexing agent includes, but is not limited to, ammonia water, sodium ethylenediamine tetraacetate, ammonium nitrate, ammonium chlorate, ammonium sulfate, and the like.
In some embodiments of the invention, in step (2), the conditions of the coprecipitation reaction include: the pH value is 10-13, preferably 11-12; the temperature is 40-80deg.C, preferably 50-70deg.C; the time is 5-50h, preferably 8-32h.
In the present invention, the filtration in step (2) is intended to remove the liquid in the solid-liquid mixture, and includes, but is not limited to, suction filtration, press filtration, centrifugation, etc.; the washing is intended to remove residual impurities in the filtered product; the drying is intended to remove residual moisture in the washing product, including but not limited to hot air drying, infrared drying, microwave drying, etc.; the screening is intended to obtain a positive electrode material precursor of a specific particle size range.
The third aspect of the present invention provides a lithium ion battery comprising the carbon-coated positive electrode material provided in the first aspect, or the carbon-coated positive electrode material prepared by the preparation method provided in the second aspect.
The carbon layer in the carbon-coated positive electrode material provided by the invention has high content, and when a pole piece is prepared at the back, only 0.1wt% of carbon nano tube is needed to be added, and other conductive agents are not needed to be added; meanwhile, the carbon coating has high bonding strength, so that the carbon coating does not fall off in the subsequent tabletting process, and meanwhile, even if the carbon nano tube added in the slurry is subjected to bridging phenomenon, a natural conductive channel can be formed due to the high carbon content of the carbon coating anode material, so that the transmission rate of lithium ions is improved.
The present invention will be described in detail by examples.
Physical properties of the high nickel cathode materials prepared in preparation examples 1 to 5 are shown in Table 1.
Preparation example 1
S1, preparing a compound with a general formula of Ni 0.83 Co 0.11 Mn 0.06 (OH) 2 Is a positive electrode material precursor Q1:
(1) Preparing a mixed salt solution with the concentration of 2mol/L by using nickel salt (nickel sulfate), cobalt salt (cobalt sulfate) and manganese salt (manganese sulfate) according to the molar ratio of 83:11:6; respectively preparing a precipitator (sodium hydroxide) and a complexing agent (ammonia water) into a precipitator solution with the concentration of 2mol/L and a complexing agent solution with the concentration of 6 mol/L;
(2) Adding the mixed salt solution, the precipitator solution and the complexing agent solution into a reaction kettle, performing coprecipitation reaction (pH value is 11.5, temperature is 65 ℃ and synthesis time is 80 h) in an inert atmosphere, and obtaining solid-liquid mixed slurry, and sequentially filtering, washing, third drying and second screening to obtain a positive electrode material precursor Q1;
s2, lithium salt (LiOH.H) 2 O), dry mixing (mixing time is 4h, mixing frequency is 35 Hz) from the positive electrode material precursor Q1 and the source E (nano zirconia) in a ball milling tank, and then performing first sintering (in an atmosphere with oxygen content of 95 vol% and temperature of 825 ℃; heating rate is 3 ℃/min; the heat preservation time is as follows 10h) The obtained primary product is crushed, crushed and sieved in turn to obtain the average particle diameter D 50 14.0 μm and a specific surface area BET of 0.55m 2 An agglomerated substrate W1 per gram;
wherein the dosage ratio of the lithium salt, the positive electrode material precursor Q1 and the E source satisfies n (Li): n (Ni+Co+M): n (E) =1.02:1:0.002;
s3, washing and drying the agglomerated substrate W1, adding a G source (tungsten oxide), and carrying out dry mixing under the condition of high-speed ball milling, wherein the mixing time is 3h, and the mixing frequency is 35Hz; in the air atmosphere, performing second sintering (the temperature is 350 ℃ and the heat preservation is carried out for 10 hours), cooling the obtained second sintering product to room temperature, crushing and sieving in sequence to obtain an agglomerated high-nickel positive electrode material P1, wherein the general formula is Li 1.02 Ni 0.826 Co 0.11 Mn 0.06 Zr 0.002 W 0.002 O 2 ；
Wherein the dosage ratio of the G source satisfies n (G) n (Ni+Co+M+E+G) =0.002:1;
the physical properties of the agglomerated high-nickel positive electrode material P1 are shown in table 1.
Preparation example 2
S1, preparing a compound with a general formula of Ni 0.91 Co 0.05 Mn 0.04 (OH) 2 Is a positive electrode material precursor Q2:
(1) Preparing a mixed salt solution with the concentration of 2mol/L by using nickel salt (nickel sulfate), cobalt salt (cobalt sulfate) and manganese salt (manganese sulfate) according to the molar ratio of 91:5:4; respectively preparing a precipitator (sodium hydroxide) and a complexing agent (ammonia water) into a precipitator solution with the concentration of 2mol/L and a complexing agent solution with the concentration of 6 mol/L;
(2) Adding the mixed salt solution, the precipitator solution and the complexing agent solution into a reaction kettle, performing coprecipitation reaction (pH value is 11.0, temperature is 55 ℃ and synthesis time is 80 h) in an inert atmosphere, and obtaining solid-liquid mixed slurry, and sequentially filtering, washing, third drying and second screening to obtain a positive electrode material precursor Q2;
s2, different from preparation example 1, the first sintering temperature was replaced by 760 ℃, and the usage ratio of the lithium salt, the positive electrode material precursor Q2, and the E source was such that n (Li): n (ni+co+m): n (E) =1.01:1:0.003;
obtain the average particle diameter D 50 13.0 μm and a specific surface area BET of 0.61m 2 An agglomerated substrate W2 per gram;
s3, unlike preparation example 1, obtaining an agglomerated high-nickel positive electrode material P2;
wherein, the physical parameters of the agglomerated high nickel positive electrode material P2 are shown in Table 1.
Preparation example 3
S1, preparing a compound with a general formula of Ni 0.83 Co 0.11 Mn 0.06 (OH) 2 Positive electrode material precursor Q3:
unlike preparation example 1, the pH of the coprecipitation reaction in step (2) was 11.8, the temperature was 50℃and the synthesis time was 60 hours, to obtain the average particle diameter D of the positive electrode material precursor Q3 50 5.2 μm;
s2, unlike in preparation example 1, the first sintering temperature was replaced with 850 ℃, and the above-mentioned lithium salt, positive electrode material precursor Q3, and E source were used in a ratio satisfying n (Li): n (ni+co+m): n (E) =1:1:0.003;
Obtain the average particle diameter D 50 4.6 μm and a specific surface BET of 0.65m 2 A single crystal substrate W3 per gram;
s3, different from preparation example 1, the temperature of the second sintering is replaced by 650 ℃, so that the monocrystalline high-nickel positive electrode material P3 is obtained.
The physical properties of the single-crystal type high-nickel positive electrode material P3 are shown in table 1.
Preparation example 4
Unlike in preparation example 1, in step S2, the first sintering temperature was replaced with 831℃to obtain an average particle size D 50 An agglomerated substrate DW1 of 16.4 μm;
in step S3, an agglomerated high-nickel positive electrode material DP1 is obtained.
Wherein, the physical parameters of the agglomerated high nickel positive electrode material DP1 are shown in Table 1.
Preparation example 5
Unlike in preparation example 3, in step S2, the first sintering temperature was changed to 816℃to obtain an average particle diameter D 50 Single crystal of 3.2 μmA substrate DW2;
in step S3, a single-crystal high-nickel positive electrode material DP2 is obtained.
The physical properties of the single-crystal type high nickel positive electrode material DP2 are shown in table 1.
TABLE 1
Note that: * When the core is selected from agglomerated high nickel positive electrode materials, the temperature T of the first sintering satisfies formula V: when the inner core is selected from single-crystal type high nickel cathode materials, the temperature T of the first sintering satisfies formula VI: /> wherein ,CNi Is the mole percent of nickel in the mixture of nickel source, cobalt source and M source, calculated as metal;
For example, in preparation example 1, the temperature T of the first sintering satisfies formula V:in preparation example 3, the temperature T of the first sintering satisfies VI: />
Table 1, below
Note that: 1-average particle diameter D of core 50 μm; average particle diameter D of primary particles in 2-agglomerate particles 50 Or the average particle diameter D of the single crystal particles 50 Nm; 3-roughness of IV b Specific surface area BET, m of the inner core 2 /g；W a The apparent density of the core, g/cm 3 。
As can be seen from the results of Table 1, the high nickel cathode materials (agglomerated high nickel cathode materials, single crystal high nickel cathode materials) prepared in preparation examples 1 to 3 have higher roughness than those prepared in preparation examples 4 to 5, which is more advantageous for tightly bonding the carbon material with the matrix material during the carbon coating process and improving the bonding strength of the carbon coating material.
Example 1
In nitrogen atmosphere, adding a carbon material (conductive carbon black) and an agglomerated high-nickel positive electrode material P1 into a high-speed mixer in a mass ratio of 1:99 for solid-phase dry coating, controlling the filling rate of a device treatment cavity to be 45%, wherein the rotating speed of the first mixed coating is controlled to be 600rpm, and the time is 20min; the rotation speed of the second mixed coating is 750rpm, and the time is 30min; the rotation speed of the third mixed coating is 1050rpm, and the time is 40min, so as to obtain a carbon-coated positive electrode material S1;
As shown in fig. 1, the SEM image of the carbon-coated cathode material S1 shows that the surface of the carbon-coated cathode material S1 is smooth, and the primary particles are round, which means that the carbon layer is uniformly coated on the surface of the primary particles and is very dense.
The physical properties of the carbon-coated cathode material S1 are shown in table 2.
Example 2
The procedure of example 1 was followed, except,
and replacing the agglomerated high-nickel positive electrode material P1 with an agglomerated high-nickel positive electrode material P2, and obtaining the carbon-coated positive electrode material S2 under the same rest conditions.
The physical properties of the carbon-coated cathode material S2 are shown in table 2.
Example 3
The procedure of example 1 was followed, except,
solid phase dry coating was performed according to the process parameters of table 2 to obtain a carbon-coated cathode material S3.
The physical properties of the carbon-coated cathode material S3 are shown in table 2.
Example 4
The procedure of example 1 was followed, except,
and replacing the carbon material with porous carbon, and obtaining the carbon-coated positive electrode material S4 under the same rest conditions.
The physical properties of the carbon-coated cathode material S4 are shown in table 2.
Example 5
The procedure of example 1 was followed, except,
the agglomerated high-nickel positive electrode material P1 was replaced with a single-crystal high-nickel positive electrode material P3, and solid-phase dry coating was performed according to the process parameters of Table 2, to obtain a carbon-coated positive electrode material S5.
The physical properties of the carbon-coated cathode material S5 are shown in table 2.
As shown in fig. 2, the SEM image of the carbon-coated cathode material S5 shows that the surface of the carbon-coated cathode material S5 is smooth, which means that the carbon layer is uniformly coated on the surface of the single crystal particles and is very dense.
Example 6
The procedure of example 1 was followed, except,
and replacing the mass ratio of the carbon material to the anode material with 1.5:98.5, and obtaining the carbon-coated anode material S6 under the same conditions.
The physical properties of the carbon-coated cathode material S6 are shown in table 2.
Example 7
The procedure of example 1 was followed, except,
and replacing the mass ratio of the carbon material to the core with 0.5:99.5, and carrying out solid-phase dry coating according to the technological parameters of Table 2 to obtain the carbon-coated positive electrode material S7.
The physical properties of the carbon-coated cathode material S7 are shown in table 2.
Example 8
The procedure of example 1 was followed, except,
and replacing the mass ratio of the carbon material to the core with 0.2:99.8, and carrying out solid-phase dry coating according to the technological parameters of Table 2 to obtain the carbon-coated positive electrode material S8.
The physical properties of the carbon-coated cathode material S8 are shown in table 2.
Comparative example 1
(1) And (3) putting 1g of conductive carbon black into a planetary ball mill, performing metal isolation treatment on the inner lining of the ball mill by using ceramic materials, wherein the ball mill beads are made of zirconia, the particle size is 1mm, performing ball milling for 2 hours at the rotating speed of the ball mill of 350rpm/min, enabling a layer of carbon material to be attached to the surface of the ball mill beads and the inner surface of ball milling equipment, separating the residual carbon material powder from the ball mill beads in a sieving way, and pouring the ball mill beads after separation into a ball milling tank for the next procedure.
(2) 99g of agglomerated high-nickel positive electrode material P1 is added into ball milling equipment according to the ball-material ratio of 1:1, and ball milling is carried out for 4 hours at the rotating speed of a ball mill of 350 rpm/min. And separating the obtained ternary material coated with a small amount of carbon material from the ball-milling beads through a sieve, and pouring the ball-milling beads after separation back to a ball-milling tank for the next process.
And (3) preparing another ball milling device (same as the above) while ball milling the ternary material, repeating the operation of the step (1), and ball milling the carbon material. After the ball milling is finished, the residual carbon material powder and ball milling beads are separated in a sieving mode, and the ball milling beads after separation are poured into a ball milling tank.
And (3) repeating the process of the step (2) to treat the high-nickel positive electrode material, and continuously increasing the carbon coating amount of the high-nickel positive electrode material. Repeating the above operation steps for 15 times to obtain the carbon-coated positive electrode material DS1.
The physical properties of the carbon-coated positive electrode material DS1 are shown in Table 2.
Comparative example 2
The procedure of comparative example 1 was followed, except that,
the agglomerated high-nickel positive electrode material P1 is replaced by a single-crystal high-nickel positive electrode material P3, and the rest conditions are the same, so that the carbon-coated positive electrode material DS2 is obtained.
The physical properties of the carbon-coated positive electrode material DS2 are shown in Table 2.
Comparative example 3
The procedure of example 1 was followed, except,
solid phase dry coating was performed according to the process parameters of table 2 to obtain a carbon-coated cathode material DS3.
The physical properties of the carbon-coated positive electrode material DS3 are shown in Table 2.
As shown in fig. 3, it can be seen from fig. 3 that the carbon-coated cathode material DS3 does not use a gradient coated material, and the uniformity of coating the carbon layer is poor, which is not beneficial to the performance of electrical properties.
Comparative example 4
The procedure of example 1 was followed, except,
and replacing the agglomerated high-nickel positive electrode material P1 with the agglomerated high-nickel positive electrode material DP1, and obtaining the carbon-coated positive electrode material DS4 under the same rest conditions.
The physical properties of the carbon-coated positive electrode material DS4 are shown in Table 2.
Comparative example 5
The procedure of example 1 was followed, except,
the agglomerated high-nickel positive electrode material P1 is replaced by a single-crystal high-nickel positive electrode material DP2, and the rest conditions are the same, so that the carbon-coated positive electrode material DS5 is obtained.
The physical properties of the carbon-coated positive electrode material DS5 are shown in Table 2.
TABLE 2
Note that: the mass ratio of the 4-carbon material to the high-nickel positive electrode material; the content of the carbon material in the 5-carbon coated positive electrode material is in weight percent.
Continuous table 2
Note that: wherein ,PDc 、AD c and TDc The compaction density, the apparent density and the tap density of the carbon-coated positive electrode material are respectively expressed in g/cm 3 ；PD x 、AD x and TDx Respectively representing the compaction density, the apparent density and the tap density of the inner core, wherein the units are g/cm 3 ；
Formula III:
continuous table 2
As can be seen from the data in table 2, compared with comparative examples 1 to 5, examples 1 to 8, which are prepared by the preparation method provided by the present invention, make the carbon layer and the core tightly combined, so that the carbon-coated cathode material not only satisfies the following conditions: the retention rate delta of the coating layer is more than or equal to 99 percent, and simultaneously meets the following conditions: the standard deviation of the carbon content test value at any three points in the carbon-coated positive electrode material is less than or equal to 0.005, and the volume impedance ratio of the carbon-coated positive electrode material to the inner core is 20-70:100,1.1Z is less than or equal to 2.5, thereby improving the capacity and the cycle performance of the carbon-coated anode material.
Compared with comparative examples 1 and comparative examples 3-4, examples 1-4 and examples 6-8 agglomerated carbon coated positive electrode materials prepared by the preparation method provided by the invention have a Z value of 1.1-1.3. Compared with comparative example 2 and comparative example 5, the single-crystal carbon-coated positive electrode material prepared in example 5 by the preparation method provided by the invention has a Z value of 1.5-2.5, which is more beneficial to improving the performance of the carbon-coated positive electrode material.
Test case
The carbon-coated positive electrode materials (S1 to S8 and DS1 to DS 5) obtained in examples 1 to 8 and comparative examples 1 to 5 were used as positive electrodes, respectively, and button cells were assembled, respectively.
The specific discharge capacity of the button cell was measured at 0.1C discharge capacity, 4.3 to 2.8V and 25℃and 80-week cycle retention at 1C and 45℃and the test results are shown in Table 3.
Among them, the 1C/1C cycle graph of the button cells assembled from the agglomerated carbon coated positive electrode materials of examples 1 to 3 and comparative example 1, respectively, at 45 ℃ and 3 to 4.3V is shown in fig. 4, and it can be seen from fig. 4 that the button cells assembled from the agglomerated carbon coated positive electrode materials of examples 1 to 3, respectively, have higher capacity retention than that of comparative example 1.
The 1C/1C cycle graph at 45 ℃ and 3-4.3V of the button cell assembled from the single-crystalline carbon-coated cathode materials of example 5 and comparative example 2, respectively, is shown in fig. 5, and it can be seen from fig. 5 that the button cell assembled from the single-crystalline carbon-coated cathode material of example 5 has a higher capacity retention rate than that of comparative example 2.
TABLE 3 Table 3
As can be seen from the data in Table 3, the button cells of examples 1 to 8, which had a carbon-coated positive electrode material structure, had higher specific discharge capacities than comparative examples 1 to 5.
Meanwhile, compared with comparative example 1, the button cell assembled by the carbon-coated positive electrode material prepared in examples 1-3 also has higher capacity retention rate; the carbon-coated positive electrode material-assembled button cell prepared in example 5 also had a higher capacity retention rate than comparative example 2.
The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the invention, all falling within the scope of protection of the invention.
Claims (15)
1. A carbon-coated positive electrode material, characterized in that the carbon-coated positive electrode material comprises: the high-nickel anode comprises an inner core and a carbon layer, wherein the inner core is made of a high-nickel anode material, and the carbon layer contains a carbon material;
wherein the carbon layer is physically adsorbed on the surface layer of the inner core; the roughness delta of the inner core is 0.1-0.45, wherein the roughness delta is defined as formula I,in the formula I, V b For the specific surface area BET, m of the inner core 2 /g；W a G/cm, the apparent density of the core 3 。
2. The carbon-coated positive electrode material according to claim 1, wherein a coating layer retention δ of the carbon-coated positive electrode material is equal to or greater than 99%, wherein δ=c 0 /C 1 ；
wherein ,C0 Carbon content of the carbon-coated positive electrode material, wt%;
C 1 the carbon content of the upper layer material after the carbon-coated positive electrode material is subjected to vibration treatment is wt%;
C 1 the test method comprises the steps of taking 200g of the carbon-coated positive electrode material for vibration treatment, wherein the amplitude of the vibration treatment is 3mm, the frequency is 250 times/min, and the time is 60min; then weighing 1g of upper material on the surface layer of the carbon-coated positive electrode material after vibration treatment, and measuring the carbon content of the upper material in weight percent;
preferably, the carbon-coated positive electrode material has a coating retention delta of 99.5-99.9%;
and/or the carbon-coated positive electrode material is prepared by solid phase dry coating.
3. The carbon-coated positive electrode material according to claim 1 or 2, wherein the high nickel positive electrode material has a composition represented by formula II,
wherein ,Lin Ni 1-x-y-a-b Co x M y E a G b O 2 (II)，
Wherein n is more than or equal to 0.9 and less than or equal to 1.5, x is more than or equal to 0 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 1, a is more than or equal to 0 and less than or equal to 0.1, b is more than or equal to 0 and less than or equal to 0+y+a+b is less than or equal to 1, M is Mn and/or Al, and E is selected from at least one of P, N, B, ti, zr, Y, al, mg elements; g is a surface coating layer selected from oxides, sulfides and fluorides containing at least one of B, al and transition elements;
and/or, in the formula II, n is more than or equal to 0.95 and less than or equal to 1.25,0.01 and less than or equal to x is more than or equal to 0.2, y is more than or equal to 0.01 and less than or equal to 0.1, a is more than or equal to 0 and less than or equal to 0.05, b is more than or equal to 0 and less than or equal to 0.05,0.02 and is less than or equal to 0.4.
4. A carbon-coated positive electrode material as claimed in any one of claims 1 to 3, wherein the roughness delta of the inner core is 0.12 to 0.38;
and/or the average particle diameter D of the inner core 50 2-16 μm, preferably 3-14 μm; specific surface area BET of 0.1-2m 2 Preferably 0.2-1.3m 2 /g；
And/or, when the inner core is selected from agglomerated particles, the roughness delta of the agglomerated particles is between 0.1 and 0.35, preferably between 0.12 and 0.25; average particle diameter D of primary particles in the agglomerate grains 50 300-700nm, preferably 350-500nm; or alternatively, the process may be performed,
when the inner core is selected from single crystal particles, the roughness delta of the single crystal particles is 0.15-0.45, preferably 0.22-0.38; the average particle diameter D of the single crystal particles 50 0.6 to 3. Mu.m, preferably 1 to 2. Mu.m.
5. The carbon-coated positive electrode material according to any one of claims 1-4, wherein the thickness of the carbon layer is 10-200nm, preferably 50-100nm;
and/or the standard deviation of the carbon content test value at any three points in the carbon-coated positive electrode material is less than or equal to 0.005, preferably less than or equal to 0.0025;
and/or, the carbon layer is composed of the carbon material;
and/or the carbon material is selected from at least one of conductive carbon black, acetylene black, furnace black, ketjen black, carbon nanotubes, carbon nanofibers, graphite particles, porous carbon, soft carbon, hard carbon, and artificial graphite.
6. The carbon-coated positive electrode material of any one of claims 1-5, wherein the volume impedance ratio of the carbon-coated positive electrode material to the core is from 20 to 70:100, preferably 30-50:100;
and/or the carbon layer is contained in an amount of 0.1 to 5wt%, preferably 0.96 to 1.47wt%, based on the total weight of the carbon-coated cathode material.
7. The carbon-coated positive electrode material of any one of claims 1-6, wherein the carbon-coated positive electrode material satisfies: z is more than or equal to 1.1 and less than or equal to 2.5, and preferably satisfies the following conditions: z is more than or equal to 1.16 and less than or equal to 2.3; wherein, wherein ,PDc 、AD c and TDc Respectively representing the compaction density, the apparent density and the tap density of the carbon-coated positive electrode material, wherein the units are g/cm 3 ；PD x 、AD x and TDx The compaction density, the apparent density and the tap density of the inner core are respectively expressed in g/cm 3 ；
Preferably, when the core is selected from an agglomerated high nickel cathode material, the carbon coated cathode material satisfies: z is more than or equal to 1.1 and less than or equal to 1.3, and preferably satisfies the following conditions: z is more than or equal to 1.16 and less than or equal to 1.23;
when the inner core is selected from single-crystal high-nickel cathode materials, the carbon-coated cathode materials satisfy: z is more than or equal to 1.5 and less than or equal to 2.5, and preferably satisfies the following conditions: z is more than or equal to 1.72 and less than or equal to 2.3;
and/or, the carbon-coated positive electrode material further satisfies formula III:
8. A method for preparing a carbon-coated positive electrode material, comprising:
in a non-oxidizing atmosphere, carrying out solid-phase dry coating on the mixed material, controlling the filling rate of a device treatment cavity to be 30-65%, and obtaining a carbon-coated positive electrode material comprising an inner core and a carbon layer;
wherein the mixed material comprises a carbon material and a high nickel anode material serving as the inner core;
wherein the solid phase dry coating process comprises a first mixed coating, a second mixed coating and a third mixed coating; the rotating speed of the first mixed coating is less than that of the second mixed coating and less than that of the third mixed coating, and the time of the first mixed coating is less than that of the second mixed coating and less than or equal to that of the third mixed coating.
9. The method of preparation of claim 8, wherein the conditions of the first hybrid coating comprise: the rotating speed is 600-800rpm, and the time is 10-30min; the conditions of the second hybrid coating include: the rotating speed is 700-1000rpm, and the time is 15-60min; the conditions of the third hybrid coating include: the rotating speed is 900-1200rpm, and the time is 20-90min;
and/or, the rotation speed ratio of the first mixed coating, the second mixed coating and the third mixed coating is 1:1.2-1.3:1.4-1.5; the time ratio of the first mixed coating, the second mixed coating and the third mixed coating is 1:1.5-2:2-3.
10. The production method according to claim 8 or 9, wherein the high-nickel positive electrode material has a composition represented by formula II, li n Ni 1-x-y-a-b Co x M y E a G b O 2 (II), wherein n is more than or equal to 0.9 and less than or equal to 1.5, x is more than or equal to 0 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 1, a is more than or equal to 0 and less than or equal to 0.1, b is more than or equal to 0 and less than or equal to x+y+a+b is less than or equal to 1, M is selected from Mn and/or Al, and E is selected from at least one of P, N, B, ti, zr, Y, al, mg elements; g is a surface coating layer selected from oxides, sulfides and fluorides containing at least one of B, al and transition elements;
preferably, in the formula II, n is more than or equal to 0.95 and less than or equal to 1.25,0.01, x is more than or equal to 0.2, y is more than or equal to 0.01 and less than or equal to 0.1, a is more than or equal to 0 and less than or equal to 0.05, b is more than or equal to 0 and less than or equal to 0.05,0.02, and x+y+a+b is more than or equal to 0.4;
and/or the mass ratio of the inner core to the carbon layer is 95-99.9:0.1 to 5, preferably 98.53 to 99.04:0.96-1.47.
11. The preparation method according to claim 10, wherein the high nickel positive electrode material is prepared by the following method:
s1, carrying out first dry mixing on lithium salt, a positive electrode material precursor and an E source, then carrying out first sintering, and sequentially crushing and sieving the obtained initial product to obtain a base material;
s2, carrying out second dry mixing on the base material and a G source, then carrying out second sintering to obtain a second sintering product, and sequentially crushing and sieving to obtain a high-nickel anode material with a composition shown in a formula II;
Wherein the positive electrode material precursor has a composition represented by formula IV: ni (Ni) 1-α-β Co α M β (OH) 2 (IV) alpha is more than or equal to 0 and less than 1, beta is more than or equal to 0 and less than 1, alpha+beta is more than 0 and less than 1, and M is selected from Mn and/or Al;
preferably, in the formula IV, alpha is more than or equal to 0.01 and less than or equal to 0.2, beta is more than or equal to 0.01 and less than or equal to 0.1,0.02 and alpha+beta is more than or equal to 0.3.
12. The production method according to claim 11, wherein, in step S1, when the core is selected from the group consisting of agglomerated high-nickel positive electrode materials, the positive electrode material precursor has an average particle diameter D 50 6-14 μm, and specific surface area BET of 4-16m 2 Per gram, bulk density is not less than 1.4g/cm 3 The tap density is more than or equal to 1.8g/cm 3 ；
Alternatively, when the core is selected from single-crystal high-nickel positive electrode materials, the positive electrode material precursor has an average particle diameter D 50 2-6 μm, and specific surface area BET of 4-30m 2 Per gram, bulk density not less than 1g/cm 3 The tap density is more than or equal to 1.4g/cm 3 。
13. The production method according to claim 11 or 12, wherein the ratio of the lithium salt, the positive electrode material precursor, and the E source is such that n (Li) n (ni+co+m) n (E) =n (Li) 1:n (E), wherein 0.9.ltoreq.n (Li) 1.5, 0.ltoreq.n (E) 0.1; preferably, the following are satisfied: n (Li) is more than or equal to 0.95 and less than or equal to 1.25,0, n (E) is more than or equal to 0.05;
and/or the E source is selected from oxide, hydroxide and carbonate containing at least one of P, N, B, ti, zr, Y, al, mg elements;
And/or the G source is selected from oxides, sulfides and fluorides containing at least one of B, al and a transition element;
and/or the G source is used in an amount such that n (Ni+Co+M+E+G) =n (G): 1, wherein 0.ltoreq.n (G) is.ltoreq.0.1, preferably 0 < n (G) is.ltoreq.0.05;
and/or, the conditions of the first dry mix and the second dry mix each independently comprise: mixing time is 0.5-6h, and mixing frequency is 30-150Hz;
and/or, the conditions of the first sintering include: the method is carried out in an atmosphere with the oxygen content of 90 to 99.5 volume percent, the temperature is 650 to 1200 ℃, the temperature rising rate is 2 to 10 ℃/min, and the constant temperature time is 6 to 20 hours;
and/or, the conditions of the second sintering include: the process is carried out in the atmosphere with the oxygen content of more than or equal to 20 volume percent, the temperature is 300-800 ℃, the heating rate is 2-10 ℃/min, and the constant temperature time is 6-20h.
14. The production method according to any one of claims 11 to 13, wherein, in step S1, when the core is selected from an agglomerated high-nickel positive electrode material, the temperature T of the first sintering satisfies formula V:
wherein ,CNi Is the mole percent of nickel in the mixture of nickel source, cobalt source and M source, calculated as metal;
alternatively, when the core is selected from single crystal high nickel positive electrode materials, the temperature T of the first sintering satisfies formula VI:
wherein ,CNi For nickel in a mixture of a nickel source, a cobalt source and an M source, calculated as metalMole percent.
15. A lithium ion battery comprising the carbon-coated positive electrode material according to any one of claims 1 to 7, or the carbon-coated positive electrode material produced by the production method according to any one of claims 8 to 14.
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| CN117117153A (en) * | 2023-10-16 | 2023-11-24 | 宁波容百新能源科技股份有限公司 | Positive electrode material, preparation method thereof and lithium ion battery |
| CN117497746A (en) * | 2023-12-29 | 2024-02-02 | 宁波容百新能源科技股份有限公司 | Sodium-electricity layered anode material and preparation method and application thereof |
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| CN117117153A (en) * | 2023-10-16 | 2023-11-24 | 宁波容百新能源科技股份有限公司 | Positive electrode material, preparation method thereof and lithium ion battery |
| CN117117153B (en) * | 2023-10-16 | 2024-02-20 | 宁波容百新能源科技股份有限公司 | Positive electrode material, preparation method thereof and lithium ion battery |
| CN117497746A (en) * | 2023-12-29 | 2024-02-02 | 宁波容百新能源科技股份有限公司 | Sodium-electricity layered anode material and preparation method and application thereof |
| CN117497746B (en) * | 2023-12-29 | 2024-05-14 | 宁波容百新能源科技股份有限公司 | Sodium-electricity layered anode material and preparation method and application thereof |
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