CN117913250A - Positive electrode material, positive electrode plate and battery - Google Patents
Positive electrode material, positive electrode plate and battery Download PDFInfo
- Publication number
- CN117913250A CN117913250A CN202410075977.3A CN202410075977A CN117913250A CN 117913250 A CN117913250 A CN 117913250A CN 202410075977 A CN202410075977 A CN 202410075977A CN 117913250 A CN117913250 A CN 117913250A
- Authority
- CN
- China
- Prior art keywords
- positive electrode
- coating layer
- electrode material
- equal
- battery
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000007774 positive electrode material Substances 0.000 title claims abstract description 148
- 239000011247 coating layer Substances 0.000 claims abstract description 106
- 239000000463 material Substances 0.000 claims abstract description 66
- 239000011159 matrix material Substances 0.000 claims abstract description 44
- 239000003792 electrolyte Substances 0.000 claims abstract description 39
- 239000010410 layer Substances 0.000 claims abstract description 32
- 239000000126 substance Substances 0.000 claims abstract description 32
- 229910011281 LiCoPO 4 Inorganic materials 0.000 claims abstract description 25
- 239000010416 ion conductor Substances 0.000 claims abstract description 22
- 238000005253 cladding Methods 0.000 claims abstract description 16
- 229910052744 lithium Inorganic materials 0.000 claims description 25
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 24
- SBLRHMKNNHXPHG-UHFFFAOYSA-N 4-fluoro-1,3-dioxolan-2-one Chemical compound FC1COC(=O)O1 SBLRHMKNNHXPHG-UHFFFAOYSA-N 0.000 claims description 19
- 229910052782 aluminium Inorganic materials 0.000 claims description 15
- 229910000625 lithium cobalt oxide Inorganic materials 0.000 claims description 13
- BFZPBUKRYWOWDV-UHFFFAOYSA-N lithium;oxido(oxo)cobalt Chemical compound [Li+].[O-][Co]=O BFZPBUKRYWOWDV-UHFFFAOYSA-N 0.000 claims description 13
- FSSPGSAQUIYDCN-UHFFFAOYSA-N 1,3-Propane sultone Chemical compound O=S1(=O)CCCO1 FSSPGSAQUIYDCN-UHFFFAOYSA-N 0.000 claims description 11
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 claims description 10
- 239000002245 particle Substances 0.000 claims description 10
- 239000000654 additive Substances 0.000 claims description 8
- 230000000996 additive effect Effects 0.000 claims description 7
- 229910000664 lithium aluminum titanium phosphates (LATP) Inorganic materials 0.000 claims description 7
- 239000003960 organic solvent Substances 0.000 claims description 7
- 150000007942 carboxylates Chemical class 0.000 claims description 6
- 150000005676 cyclic carbonates Chemical class 0.000 claims description 6
- 229910052727 yttrium Inorganic materials 0.000 claims description 5
- NRJJZXGPUXHHTC-UHFFFAOYSA-N [Li+].[O--].[O--].[O--].[O--].[Zr+4].[La+3] Chemical compound [Li+].[O--].[O--].[O--].[O--].[Zr+4].[La+3] NRJJZXGPUXHHTC-UHFFFAOYSA-N 0.000 claims description 4
- CVJYOKLQNGVTIS-UHFFFAOYSA-K aluminum;lithium;titanium(4+);phosphate Chemical compound [Li+].[Al+3].[Ti+4].[O-]P([O-])([O-])=O CVJYOKLQNGVTIS-UHFFFAOYSA-K 0.000 claims description 4
- 150000002736 metal compounds Chemical class 0.000 claims description 4
- KFDQGLPGKXUTMZ-UHFFFAOYSA-N [Mn].[Co].[Ni] Chemical compound [Mn].[Co].[Ni] KFDQGLPGKXUTMZ-UHFFFAOYSA-N 0.000 claims description 2
- DGQGEJIVIMHONW-UHFFFAOYSA-N [O-2].[Ta+5].[Zr+4].[La+3].[Li+] Chemical compound [O-2].[Ta+5].[Zr+4].[La+3].[Li+] DGQGEJIVIMHONW-UHFFFAOYSA-N 0.000 claims description 2
- 229910052721 tungsten Inorganic materials 0.000 claims description 2
- 239000002344 surface layer Substances 0.000 abstract description 22
- 230000008859 change Effects 0.000 abstract description 9
- 238000007086 side reaction Methods 0.000 abstract description 8
- 238000002360 preparation method Methods 0.000 description 80
- 239000011248 coating agent Substances 0.000 description 38
- 238000000576 coating method Methods 0.000 description 38
- 238000006243 chemical reaction Methods 0.000 description 36
- 239000000243 solution Substances 0.000 description 28
- 238000002156 mixing Methods 0.000 description 25
- 238000003756 stirring Methods 0.000 description 24
- 239000002243 precursor Substances 0.000 description 19
- 238000001354 calcination Methods 0.000 description 17
- 230000000052 comparative effect Effects 0.000 description 17
- 230000000694 effects Effects 0.000 description 17
- 239000000203 mixture Substances 0.000 description 16
- 230000007704 transition Effects 0.000 description 15
- 239000012071 phase Substances 0.000 description 14
- 238000005245 sintering Methods 0.000 description 14
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 13
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 12
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 12
- 229910001416 lithium ion Inorganic materials 0.000 description 12
- 239000012266 salt solution Substances 0.000 description 12
- 239000010936 titanium Substances 0.000 description 12
- -1 borate compound Chemical class 0.000 description 11
- 150000001875 compounds Chemical class 0.000 description 11
- 230000001276 controlling effect Effects 0.000 description 11
- 238000000034 method Methods 0.000 description 11
- 229910017052 cobalt Inorganic materials 0.000 description 10
- 239000010941 cobalt Substances 0.000 description 10
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 10
- 150000002500 ions Chemical class 0.000 description 10
- 239000000758 substrate Substances 0.000 description 10
- 239000010405 anode material Substances 0.000 description 9
- 239000008139 complexing agent Substances 0.000 description 9
- 239000006258 conductive agent Substances 0.000 description 9
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 8
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 description 8
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 8
- 239000011230 binding agent Substances 0.000 description 8
- 230000008569 process Effects 0.000 description 8
- 238000005303 weighing Methods 0.000 description 8
- 230000010287 polarization Effects 0.000 description 7
- 229910018134 Al-Mg Inorganic materials 0.000 description 6
- 229910018467 Al—Mg Inorganic materials 0.000 description 6
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 6
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 description 6
- 229910052808 lithium carbonate Inorganic materials 0.000 description 6
- 239000002904 solvent Substances 0.000 description 6
- 239000008367 deionised water Substances 0.000 description 5
- 229910021641 deionized water Inorganic materials 0.000 description 5
- 229910003002 lithium salt Inorganic materials 0.000 description 5
- 159000000002 lithium salts Chemical class 0.000 description 5
- 238000001878 scanning electron micrograph Methods 0.000 description 5
- 239000004408 titanium dioxide Substances 0.000 description 5
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 4
- 239000002033 PVDF binder Substances 0.000 description 4
- 229910000329 aluminium sulfate Inorganic materials 0.000 description 4
- DIZPMCHEQGEION-UHFFFAOYSA-H aluminium sulfate (anhydrous) Chemical compound [Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O DIZPMCHEQGEION-UHFFFAOYSA-H 0.000 description 4
- 235000011114 ammonium hydroxide Nutrition 0.000 description 4
- 239000007864 aqueous solution Substances 0.000 description 4
- 239000012298 atmosphere Substances 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 239000010406 cathode material Substances 0.000 description 4
- 150000001868 cobalt Chemical class 0.000 description 4
- 239000013256 coordination polymer Substances 0.000 description 4
- 238000009792 diffusion process Methods 0.000 description 4
- 239000012153 distilled water Substances 0.000 description 4
- 238000009826 distribution Methods 0.000 description 4
- 239000011267 electrode slurry Substances 0.000 description 4
- 238000001914 filtration Methods 0.000 description 4
- 230000006872 improvement Effects 0.000 description 4
- 239000011261 inert gas Substances 0.000 description 4
- 239000007791 liquid phase Substances 0.000 description 4
- 229910052943 magnesium sulfate Inorganic materials 0.000 description 4
- 230000014759 maintenance of location Effects 0.000 description 4
- 238000012544 monitoring process Methods 0.000 description 4
- 239000007773 negative electrode material Substances 0.000 description 4
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 4
- 239000002994 raw material Substances 0.000 description 4
- 229910000029 sodium carbonate Inorganic materials 0.000 description 4
- 238000010998 test method Methods 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 3
- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 description 3
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 description 3
- 102100027368 Histone H1.3 Human genes 0.000 description 3
- 101001009450 Homo sapiens Histone H1.3 Proteins 0.000 description 3
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 description 3
- 229910002651 NO3 Inorganic materials 0.000 description 3
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 3
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 3
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 3
- 238000005054 agglomeration Methods 0.000 description 3
- 230000002776 aggregation Effects 0.000 description 3
- 230000008901 benefit Effects 0.000 description 3
- 239000001569 carbon dioxide Substances 0.000 description 3
- 229910002092 carbon dioxide Inorganic materials 0.000 description 3
- 238000007600 charging Methods 0.000 description 3
- 238000007599 discharging Methods 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 229910002804 graphite Inorganic materials 0.000 description 3
- 239000010439 graphite Substances 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 3
- SIWVEOZUMHYXCS-UHFFFAOYSA-N oxo(oxoyttriooxy)yttrium Chemical compound O=[Y]O[Y]=O SIWVEOZUMHYXCS-UHFFFAOYSA-N 0.000 description 3
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 description 3
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 description 3
- 229910001928 zirconium oxide Inorganic materials 0.000 description 3
- UHOPWFKONJYLCF-UHFFFAOYSA-N 2-(2-sulfanylethyl)isoindole-1,3-dione Chemical compound C1=CC=C2C(=O)N(CCS)C(=O)C2=C1 UHOPWFKONJYLCF-UHFFFAOYSA-N 0.000 description 2
- 229920000049 Carbon (fiber) Polymers 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- OMOVVBIIQSXZSZ-UHFFFAOYSA-N [6-(4-acetyloxy-5,9a-dimethyl-2,7-dioxo-4,5a,6,9-tetrahydro-3h-pyrano[3,4-b]oxepin-5-yl)-5-formyloxy-3-(furan-3-yl)-3a-methyl-7-methylidene-1a,2,3,4,5,6-hexahydroindeno[1,7a-b]oxiren-4-yl] 2-hydroxy-3-methylpentanoate Chemical compound CC12C(OC(=O)C(O)C(C)CC)C(OC=O)C(C3(C)C(CC(=O)OC4(C)COC(=O)CC43)OC(C)=O)C(=C)C32OC3CC1C=1C=COC=1 OMOVVBIIQSXZSZ-UHFFFAOYSA-N 0.000 description 2
- 239000006230 acetylene black Substances 0.000 description 2
- 239000011149 active material Substances 0.000 description 2
- 229910021383 artificial graphite Inorganic materials 0.000 description 2
- 239000004917 carbon fiber Substances 0.000 description 2
- 125000004122 cyclic group Chemical group 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 230000003111 delayed effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 description 2
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 description 2
- FKRCODPIKNYEAC-UHFFFAOYSA-N ethyl propionate Chemical compound CCOC(=O)CC FKRCODPIKNYEAC-UHFFFAOYSA-N 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 239000011888 foil Substances 0.000 description 2
- 230000002427 irreversible effect Effects 0.000 description 2
- IIPYXGDZVMZOAP-UHFFFAOYSA-N lithium nitrate Chemical compound [Li+].[O-][N+]([O-])=O IIPYXGDZVMZOAP-UHFFFAOYSA-N 0.000 description 2
- 229910001512 metal fluoride Inorganic materials 0.000 description 2
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- 229910001463 metal phosphate Inorganic materials 0.000 description 2
- 238000006386 neutralization reaction Methods 0.000 description 2
- KJFMBFZCATUALV-UHFFFAOYSA-N phenolphthalein Chemical compound C1=CC(O)=CC=C1C1(C=2C=CC(O)=CC=2)C2=CC=CC=C2C(=O)O1 KJFMBFZCATUALV-UHFFFAOYSA-N 0.000 description 2
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 2
- 239000004810 polytetrafluoroethylene Substances 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 239000011163 secondary particle Substances 0.000 description 2
- 239000011734 sodium Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- VAYTZRYEBVHVLE-UHFFFAOYSA-N 1,3-dioxol-2-one Chemical compound O=C1OC=CO1 VAYTZRYEBVHVLE-UHFFFAOYSA-N 0.000 description 1
- VTHRQKSLPFJQHN-UHFFFAOYSA-N 3-[2-(2-cyanoethoxy)ethoxy]propanenitrile Chemical compound N#CCCOCCOCCC#N VTHRQKSLPFJQHN-UHFFFAOYSA-N 0.000 description 1
- 229910016569 AlF 3 Inorganic materials 0.000 description 1
- 229910017119 AlPO Inorganic materials 0.000 description 1
- 102100028667 C-type lectin domain family 4 member A Human genes 0.000 description 1
- 229910021503 Cobalt(II) hydroxide Inorganic materials 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 101000766908 Homo sapiens C-type lectin domain family 4 member A Proteins 0.000 description 1
- 229910002319 LaF3 Inorganic materials 0.000 description 1
- 101150058243 Lipf gene Proteins 0.000 description 1
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 1
- 230000010718 Oxidation Activity Effects 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- XBDQKXXYIPTUBI-UHFFFAOYSA-M Propionate Chemical compound CCC([O-])=O XBDQKXXYIPTUBI-UHFFFAOYSA-M 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- HMDDXIMCDZRSNE-UHFFFAOYSA-N [C].[Si] Chemical compound [C].[Si] HMDDXIMCDZRSNE-UHFFFAOYSA-N 0.000 description 1
- DPXJVFZANSGRMM-UHFFFAOYSA-N acetic acid;2,3,4,5,6-pentahydroxyhexanal;sodium Chemical compound [Na].CC(O)=O.OCC(O)C(O)C(O)C(O)C=O DPXJVFZANSGRMM-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000002696 acid base indicator Substances 0.000 description 1
- BTGRAWJCKBQKAO-UHFFFAOYSA-N adiponitrile Chemical compound N#CCCCCC#N BTGRAWJCKBQKAO-UHFFFAOYSA-N 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 239000012300 argon atmosphere Substances 0.000 description 1
- 230000002238 attenuated effect Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000002041 carbon nanotube Substances 0.000 description 1
- 229910021393 carbon nanotube Inorganic materials 0.000 description 1
- 239000001768 carboxy methyl cellulose Substances 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 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
- 229940044175 cobalt sulfate Drugs 0.000 description 1
- 229910000361 cobalt sulfate Inorganic materials 0.000 description 1
- KTVIXTQDYHMGHF-UHFFFAOYSA-L cobalt(2+) sulfate Chemical compound [Co+2].[O-]S([O-])(=O)=O KTVIXTQDYHMGHF-UHFFFAOYSA-L 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
- QAHREYKOYSIQPH-UHFFFAOYSA-L cobalt(II) acetate Chemical compound [Co+2].CC([O-])=O.CC([O-])=O QAHREYKOYSIQPH-UHFFFAOYSA-L 0.000 description 1
- ASKVAEGIVYSGNY-UHFFFAOYSA-L cobalt(ii) hydroxide Chemical compound [OH-].[OH-].[Co+2] ASKVAEGIVYSGNY-UHFFFAOYSA-L 0.000 description 1
- 238000010280 constant potential charging Methods 0.000 description 1
- 238000010277 constant-current charging Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000011889 copper foil Substances 0.000 description 1
- 229910052593 corundum Inorganic materials 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000001351 cycling effect Effects 0.000 description 1
- 238000013500 data storage Methods 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- YNQRWVCLAIUHHI-UHFFFAOYSA-L dilithium;oxalate Chemical compound [Li+].[Li+].[O-]C(=O)C([O-])=O YNQRWVCLAIUHHI-UHFFFAOYSA-L 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 239000008151 electrolyte solution Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 230000014509 gene expression Effects 0.000 description 1
- 238000005087 graphitization Methods 0.000 description 1
- 229910021385 hard carbon Inorganic materials 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 239000003273 ketjen black Substances 0.000 description 1
- MRELNEQAGSRDBK-UHFFFAOYSA-N lanthanum oxide Inorganic materials [O-2].[O-2].[O-2].[La+3].[La+3] MRELNEQAGSRDBK-UHFFFAOYSA-N 0.000 description 1
- XIXADJRWDQXREU-UHFFFAOYSA-M lithium acetate Chemical compound [Li+].CC([O-])=O XIXADJRWDQXREU-UHFFFAOYSA-M 0.000 description 1
- 229940071264 lithium citrate Drugs 0.000 description 1
- WJSIUCDMWSDDCE-UHFFFAOYSA-K lithium citrate (anhydrous) Chemical compound [Li+].[Li+].[Li+].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O WJSIUCDMWSDDCE-UHFFFAOYSA-K 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
- 229910001386 lithium phosphate Inorganic materials 0.000 description 1
- 229910001635 magnesium fluoride Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- STZCRXQWRGQSJD-GEEYTBSJSA-M methyl orange Chemical compound [Na+].C1=CC(N(C)C)=CC=C1\N=N\C1=CC=C(S([O-])(=O)=O)C=C1 STZCRXQWRGQSJD-GEEYTBSJSA-M 0.000 description 1
- 229940012189 methyl orange Drugs 0.000 description 1
- CEQFOVLGLXCDCX-WUKNDPDISA-N methyl red Chemical compound C1=CC(N(C)C)=CC=C1\N=N\C1=CC=CC=C1C(O)=O CEQFOVLGLXCDCX-WUKNDPDISA-N 0.000 description 1
- 239000004005 microsphere Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- YKYONYBAUNKHLG-UHFFFAOYSA-N n-Propyl acetate Natural products CCCOC(C)=O YKYONYBAUNKHLG-UHFFFAOYSA-N 0.000 description 1
- 229910021382 natural graphite Inorganic materials 0.000 description 1
- KTUFCUMIWABKDW-UHFFFAOYSA-N oxo(oxolanthaniooxy)lanthanum Chemical compound O=[La]O[La]=O KTUFCUMIWABKDW-UHFFFAOYSA-N 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 229920000058 polyacrylate Polymers 0.000 description 1
- 229920006254 polymer film Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 229940090181 propyl acetate Drugs 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 235000019812 sodium carboxymethyl cellulose Nutrition 0.000 description 1
- 229920001027 sodium carboxymethylcellulose Polymers 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- IAHFWCOBPZCAEA-UHFFFAOYSA-N succinonitrile Chemical compound N#CCCC#N IAHFWCOBPZCAEA-UHFFFAOYSA-N 0.000 description 1
- 238000004448 titration Methods 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 150000003624 transition metals Chemical class 0.000 description 1
- BYMUNNMMXKDFEZ-UHFFFAOYSA-K trifluorolanthanum Chemical compound F[La](F)F BYMUNNMMXKDFEZ-UHFFFAOYSA-K 0.000 description 1
- TWQULNDIKKJZPH-UHFFFAOYSA-K trilithium;phosphate Chemical compound [Li+].[Li+].[Li+].[O-]P([O-])([O-])=O TWQULNDIKKJZPH-UHFFFAOYSA-K 0.000 description 1
- 238000009461 vacuum packaging Methods 0.000 description 1
- NQPDZGIKBAWPEJ-UHFFFAOYSA-N valeric acid Chemical compound CCCCC(O)=O NQPDZGIKBAWPEJ-UHFFFAOYSA-N 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
- 229910001845 yogo sapphire Inorganic materials 0.000 description 1
Abstract
The invention provides a positive electrode material, a positive electrode plate and a battery comprising the positive electrode material, wherein the positive electrode material comprises a positive electrode base material, and a first coating layer and a second coating layer which are coated on the positive electrode base material; the first coating layer comprises a fast ion conductor substance; the second cladding layer includes LiCoPO 4. The positive electrode material provided by the invention improves the phase change problem of the surface layer structure of the positive electrode active matrix material; and the side reaction at the interface of the positive electrode active matrix material and the electrolyte can be effectively inhibited, and the cycle stability of the battery is improved.
Description
Technical Field
The invention relates to the technical field of batteries, in particular to a positive electrode material, a positive electrode plate comprising the positive electrode material and a battery comprising the positive electrode material and/or the positive electrode plate.
Background
Along with the increasingly light and thin development of consumer electronic products such as mobile phones and flat plates, the demand of batteries on energy density is continuously improved, the currently commonly used positive electrode material with high energy density is considered as an effective way for improving the energy density of the batteries, so that the future demand of the positive electrode material is continuously pursued for voltage improvement, but under high voltage, the positive electrode material is easy to have problems of surface layer structure phase change and the like, so that the capacity of the positive electrode material is accelerated and attenuated, and the cycle performance of the batteries is influenced.
Disclosure of Invention
In order to solve the above problems in the prior art, the present invention provides a positive electrode material, and a positive electrode sheet and a battery including the same. The positive electrode material provided by the invention can avoid phase change of the surface layer structure of the positive electrode active matrix material; and the side reaction at the interface of the positive electrode active matrix material and the electrolyte can be effectively inhibited, and the cycle stability of the battery is improved.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
The first aspect of the present invention provides a positive electrode material, which comprises a positive electrode base material, and a first coating layer and a second coating layer coated on the positive electrode base material; the first coating layer comprises a fast ion conductor substance; the second cladding layer includes LiCoPO 4.
A second aspect of the invention provides a positive electrode sheet comprising the positive electrode material of the first aspect of the invention.
A third aspect of the invention provides a battery comprising an electrolyte and the positive electrode material according to the first aspect of the invention and/or the positive electrode sheet according to the second aspect of the invention.
Through the technical scheme, compared with the prior art, the invention has at least the following advantages:
1. According to the positive electrode material provided by the invention, the rapid ion conductor substance is coated on the positive electrode substrate material to serve as a first coating layer, and the high-voltage-resistant LiCoPO 4 material is coated on the positive electrode substrate material to serve as a second coating layer, so that on one hand, the problems of surface layer structural phase change and the like of the positive electrode substrate material can be effectively solved, and the electrochemical performance of the positive electrode material used under high voltage is improved; on the other hand, the side reaction at the interface of the positive electrode matrix material and the electrolyte can be effectively inhibited, and the circulation stability of the positive electrode material is improved;
2. According to the positive electrode material provided by the invention, the first coating layer and the second coating layer are coated on the positive electrode substrate material, so that on one hand, poor coating effect caused by local agglomeration of the coating layer material can be avoided, and on the other hand, the increase of surface impedance of the positive electrode substrate material caused by direct contact of a fast ion conductor substance with water and carbon dioxide in an electrolyte can be avoided;
3. according to the positive electrode material provided by the invention, the fast ion conductor substance is used as the intermediate transition layer, so that the diffusion rate of active ions near the surface layer of the positive electrode substrate material can be effectively increased, the polarization generated in the charge and discharge process of the positive electrode material is reduced, and the DCR is further reduced;
4. the battery provided by the invention comprises the positive plate and/or the positive material, and the structural stability of the near-surface layer is effectively improved due to the positive plate and/or the positive material, so that gram capacity is not excessively sacrificed, and the battery has good cycle stability and higher gram capacity exertion under the high-voltage use condition.
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.
Drawings
FIG. 1 is a SEM image of the positive electrode material of example I-4 of example II-4 provided by the invention;
FIG. 2 is a SEM image of a section of the positive electrode material CP of example I-4 of example II-4 provided by the invention;
FIG. 3 is a La-element surface-scanning EDS diagram of the CP cross section of the positive electrode material of example I-4 in example II-4 provided by the invention;
FIG. 4 is a P-element surface-scanning EDS (electronic data storage System) diagram of a CP section of the positive electrode material of the embodiment I-4 in the embodiment II-4 provided by the invention.
Detailed Description
The following describes specific embodiments of the present invention in detail. It should be understood that the detailed description and specific examples, while indicating and illustrating the invention, are not intended to limit the invention.
In the present invention, the term "high voltage condition/high voltage" means that the operating voltage of the whole cell is not less than 4.48V, such as 4.48V, 4.5V, 4.53V or 4.55V.
The first aspect of the present invention provides a positive electrode material, which comprises a positive electrode base material, and a first coating layer and a second coating layer coated on the positive electrode base material; the first coating layer comprises a fast ion conductor substance; the second cladding layer includes LiCoPO 4.
In the invention, the positive electrode material has a multi-layer coating structure, and the outermost layer is coated by LiCoPO 4, namely a second coating layer; the intermediate transition layer is coated by a fast ion conductor substance, namely a first coating layer; the second coating layer is coated on the outer side surface of the first coating layer, and the first coating layer is positioned between the positive electrode base material and the second coating layer.
In the present invention, liCoPO 4 (abbreviated as LCPO) is included in the coating material of the second coating layer (i.e., the outermost layer). It can be understood that LCPO is used as a special coating substance, is still electrochemically stable at the upper limit voltage of 4.7V (vs. Li/Li +), and has a strong covalent P-O tetrahedral configuration formed at the interface of the outer surface of LCPO, so that the formation of harmful H1-3 phases of the positive electrode material can be effectively relieved, the stability of the structure is improved, and the capacity loss of the positive electrode material is avoided; meanwhile LCPO as a special coating substance can effectively inhibit side reactions at the interface of the positive electrode matrix material and the electrolyte, so that the positive electrode matrix material subjected to LCPO coating modification shows cycle stability under high voltage.
Furthermore, the strong covalent P-O tetrahedral configuration formed at the LCPO external surface interface can also play a role in reducing the oxidation activity of LCPO surface O, can effectively inhibit the release of lattice O and the occurrence of irreversible phase change in the high-voltage positive electrode matrix material circulation process, further improves the structural stability of the positive electrode material, and avoids the capacity loss of the battery.
In the present invention, a fast ion conductor substance is included in the coating material of the first coating layer, and the first coating layer is interposed between the positive electrode base material and the second coating layer as an intermediate transition layer.
LCPO although the stability of the crystal structure of the positive electrode matrix material can be improved, the poor electronic conductivity and ion conductivity of the material can cause the increase of the impedance of the surface of the positive electrode material, so that the electrochemical polarization of the positive electrode material in the charge-discharge reaction process is increased.
To further avoid an increase in the surface impedance of the positive electrode material, which in one example is at 4.53V, the DCR at 70% soc is less than or equal to 55mΩ, reducing the electrochemical polarization generated by the battery during charge and discharge. The "DCR in 70% SOC State" refers to the Direct current internal resistance (DCIR or DCR) of a battery made of the positive electrode material at 70% State of charge (SOC). The direct-current internal resistance of the battery made of the positive electrode material under the voltage condition of 4.53V in the 70% charge state is controlled to be less than or equal to 55mΩ, so that the diffusion efficiency of positive electrode active ions near the surface layer of the positive electrode material can be effectively improved, the electrochemical polarization generated in the charging and discharging process of the battery is reduced, and the performance of the battery is improved. In yet another example, the cathode material has a DCR of less than or equal to 60mΩ at 4.55V at 70% SOC. The direct current internal resistance of the battery core made of the positive electrode material under the voltage condition of 4.55V in the 70% charge state is controlled to be less than or equal to 60mΩ, so that the benefit can be further increased, and the battery performance is improved.
Further, the fast ion conductor substance and LCPO are mixed and then coated together, so that the two substances are easy to agglomerate, the local dispersion effect is poor, the surface layer of the positive electrode material still generates structural phase change, or the local electron and ion conductivity is poor, so that the impedance of the surface of the positive electrode material is increased, therefore, the fast ion conductor substance is used as a first coating layer and is arranged into a multi-layer coating structure, the intermediate transition layer between the second coating layer LCPO and the positive electrode substrate, and the direct current internal resistance of a battery core made of the positive electrode material under the voltage condition of 4.53V in the 70% charge state is less than or equal to 55mΩ (and/or DCR under the voltage condition of 4.55V in the 70% SOC state is less than or equal to 60mΩ), on one hand, the fast ion conductor substance and LCPO are prevented from agglomerating, the coating effect of the second coating layer LCPO is optimal, the effect of improving the structural stability of the surface layer of the positive electrode material is achieved, the auxiliary reaction of the positive electrode substrate and the electrolyte is prevented, and the cycling stability of the positive electrode material under the high voltage condition is further improved; on the other hand, the diffusion efficiency of positive active ions near the surface layer of the positive electrode material can be effectively improved, the increase of the impedance of the surface of the positive electrode material is effectively avoided, the electrochemical polarization generated in the charge and discharge process of the battery is reduced, and the performance of the battery is improved.
In one example, the positive electrode material surface Li 2CO3 is less than or equal to 200ppm. The fast ion conductor substance is easy to react with water and carbon dioxide in the air to generate Li 2CO3 on the surface of the positive electrode material, which can lead the fast ion conductor substance to be rapidly degraded in the air, thereby causing the surface impedance of the positive electrode matrix material to be increased and affecting the electrochemical performance of the positive electrode material. Therefore, the invention sets two substances into a multi-layer coating structure, takes the fast ion conductor substance as an intermediate transition layer, can avoid degradation caused by direct contact reaction between the fast ion conductor substance and water and carbon dioxide in the air, further controls the Li 2CO3 content on the surface of the positive electrode material to be less than or equal to 200ppm, can avoid the increase of the surface impedance of the positive electrode matrix material, and reduces the electrochemical polarization generated in the charge and discharge process of the battery and the influence on the battery performance. The specific test method for the content of the residual Li 2CO3 on the surface of the positive electrode material is as follows: acid-base neutralization titration experiments were performed using acid (or base) of known mass concentration to determine the residual Li 2CO3 on the surface of the positive electrode material. In the test, phenolphthalein, methyl orange, methyl red and the like are used as acid-base indicators to judge whether the neutralization is complete.
In one example, a third coating layer is further coated between the positive electrode base material and the first coating layer, the third coating layer including a metal compound. The third coating layer is coated on the outer side surface of the positive electrode base material and is arranged between the positive electrode base material and the first coating layer.
The above-described solution of the invention thus already enables better results than the prior art. In order to further enhance the effect, one or more of the following schemes may be further defined.
In the present invention, the fast ion conductor substance includes one or more of lithium aluminum titanium phosphate (Li 1.3Al0.3Ti1.7P3O12, abbreviated as LATP), lithium lanthanum zirconium oxide (Li 7La3Zr2O12, abbreviated as LLZO), and lithium lanthanum zirconium tantalum oxide (Li 6.75La3Zr1.75Ta0.25O12, abbreviated as LLZTO). In one example, the fast ion conductor species includes lithium aluminum titanium phosphate and/or lithium lanthanum zirconium oxide.
In the present invention, the first coating layer may account for 0.03% to 5% of the total mass of the positive electrode base material, and illustratively, the first coating layer may account for 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 2%, 3%, 4%, 5%, preferably 0.05% to 3% of the total mass of the positive electrode base material. When the mass ratio of the first coating layer in the positive electrode matrix material is less than 0.03%, the conductivity and the lithium ion transmission rate of the surface layer of the positive electrode material are not obviously improved, electrochemical polarization still exists in the charge and discharge process, so that the impedance of the surface layer of the positive electrode material is larger, and when the mass ratio of the first coating layer is more than 5%, the fast ion conductor does not have capacity contribution, and when the coating amount is too large, the gram capacity exertion of the positive electrode material is reduced. Therefore, by controlling the mass ratio of the first coating layer in the positive electrode material within a specific range, the increase of the impedance of the surface of the positive electrode material can be avoided, and the diffusion efficiency of positive active ions near the surface layer of the positive electrode material can be further improved, so that the initial efficiency and gram capacity of a battery made of the positive electrode material are improved.
In the present invention, the second coating layer may be 0.05% to 5% of the total mass of the positive electrode base material, and illustratively, the second coating layer may be 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 2%, 3%, 4%, 5%, preferably 0.08% to 3% of the total mass of the positive electrode base material. It is understood that when the mass ratio of the second coating layer in the positive electrode base material is less than 0.05%, the coating effect is poor, so that the structural stability of the surface of the positive electrode material is reduced, and when the mass ratio of the second coating layer in the positive electrode base material is more than 5%, the coating amount of LCPO is excessive, the conductivity of the surface of the positive electrode material is reduced, so that the surface impedance of the positive electrode material is increased, thereby being unfavorable for the charge-discharge reaction, and simultaneously, the gram capacity of the positive electrode material is sacrificed. Therefore, the mass ratio of the second coating layer in the positive electrode material is controlled within a specific range, so that the surface structural stability of the positive electrode material in the charge and discharge process is fully improved and the phase change is delayed on the premise that the gram capacity of the positive electrode material is not excessively sacrificed while the surface impedance of the positive electrode material is not increased, and the electrochemical performance and the cycle performance of the battery are effectively improved.
In the present invention, in order to further enhance the coating effect of the first coating layer, to avoid the sacrifice of gram capacity caused by the increase of the impedance of the surface of the positive electrode material, the electrochemical performance and the cycle performance of the battery are enhanced, and in one example, the thickness of the first coating layer is 5nm to 1000nm. The thickness of the first coating layer may be 5nm、10nm、20nm、30nm、40nm、50nm、60nm、70nm、80nm、90nm、100nm、200nm、300nm、400nm、500nm、600nm、700nm、800nm、900nm、1000nm or any two sets of values. In one example, the first cladding layer has a thickness of 20nm to 800nm.
Further, in one example, the second cladding layer has a thickness of 10nm to 1000nm. The thickness of the second cladding layer may be 10nm、20nm、30nm、40nm、50nm、60nm、70nm、80nm、90nm、100nm、200nm、300nm、400nm、500nm、600nm、700nm、800nm、900nm、1000nm or a range of any two sets of values, for example. In one example, the second cladding layer has a thickness of 20nm to 800nm. The thicknesses of the first coating layer and the second coating layer are average values of thicknesses measured by a plurality of point values.
The thickness of the first coating layer and the second coating layer can be influenced by the ratio of the total mass of the positive electrode base material to a certain extent, the electric conductivity and the lithium ion transmission rate of the surface layer of the positive electrode material can be ensured, the impedance of the surface of the positive electrode material can be improved, the gram capacity of the positive electrode material can be improved, the surface structural stability of the positive electrode material in the charging and discharging processes can be fully improved, the phase change can be delayed, the occurrence of side reaction of electrolyte can be further reduced, and the electrochemical performance and the cycle performance of the battery can be further improved.
Still further, in one example, the total thickness of the first cladding layer and the second cladding layer is 15nm to 2000nm. Illustratively, the total thickness of the first cladding layer and the second cladding layer is 15nm、20nm、30nm、40nm、50nm、60nm、70nm、80nm、90nm、100nm、200nm、300nm、400nm、500nm、600nm、700nm、800nm、900nm、1000nm、1100nm、1200nm、1300nm、1400nm、1500nm、1600nm、1700nm、1800nm、1900nm、2000nm or a range of any two sets of values. In one example, the first cladding layer and the second cladding layer have a total thickness of 40nm to 1600nm. In addition, through regulating and controlling the total thickness of the first coating layer and the second coating layer to be in a proper range, the conductivity of the surface layer of the anode material can be better improved, the transmission rate of lithium ions is accelerated, the problem that the side reaction of electrolyte is too fast under high voltage is restrained, the stability of the electrolyte and the interface thereof is obviously improved, the problems of gas production during storage, cyclic expansion and the like are avoided, the integrity of anode material particles can be effectively ensured, the coating effect is improved, and the capacity retention rate and the cyclic performance of a battery are improved.
In the invention, in order to improve the coating effect of the multilayer coating structure, local agglomeration of the coating layer material is avoided. In one example, the second coating layer is coated on the first coating layer in a dot shape, and the second coating layer accounts for 30% -100% of the total coverage area of the first coating layer. It can be understood that by controlling the distribution condition of the coating of the second coating layer and the area ratio of the first coating layer, the situation of local uneven distribution or agglomeration can be avoided as much as possible, and the benefit of the multilayer coating structure can be increased. In yet another example, the second cladding layer comprises 40% -90% of the total coverage area of the first cladding layer.
In the present invention, in order to obtain better electrochemical performance and provide higher gram capacity and better cycle performance of a battery made using the positive electrode material, in an example, the particle diameter D v50 of the positive electrode material is 3 μm to 28 μm, and the particle diameter D v50 of the positive electrode material may be 3 μm, 4 μm, 5 μm, 8 μm, 10 μm, 15 μm, 16 μm, 18 μm, 20 μm, 23 μm, 24 μm, 25 μm, 28 μm or a range of any two sets of values. In one example, the particle size D v50 of the positive electrode material is 4 μm to 25 μm.
In the present invention, the positive electrode base material may include a lithium cobaltate material or a nickel cobalt manganese ternary material. It has been found through research that the main phase transition restricting the application of lithium cobaltate materials under high voltage conditions occurs at 4.55V (vs Li +/Li), i.e. at this voltage, the O3 phase of lithium cobaltate undergoes an irreversible phase transition towards the H1-3 phase, whereas the ionic and electronic conductivity of lithium cobaltate in the H1-3 phase is poor, which leads to an accelerated capacity decay of the lithium cobaltate material. Therefore, the problem of phase change of the surface structure of the positive electrode base material can be effectively solved by coating the coating layer on the positive electrode base material, so that the electrochemical performance and the cycle performance of the positive electrode material under high voltage are improved.
In the invention, the chemical formula of the lithium cobaltate material is Li xMezMyO2, wherein Me=Co 1-a-bAlaZb, M is one or more of Al, mg, ti, zr, co, ni, mn, Y, la, sr, W, sc, Z is one or more of Y, la, mg, ti, zr, ni, mn, ce, x is more than or equal to 0.95 and less than or equal to 1.05,0 and less than or equal to 0.2, Z is more than or equal to 0.8 and less than or equal to 1, a is more than or equal to 0 and less than or equal to 0.2, and b is more than or equal to 0 and less than or equal to 0.2.
In the invention, the preparation raw materials of the lithium cobaltate material at least comprise Me 3O4 which is a precursor of Al and Z doped cobalt, wherein Me=Co 1-a-bAlaZb and Z is one or more of Y, la, mg, ti, zr, ni, mn, nb; 0<a is less than or equal to 0.2, and 0< b is less than or equal to 0.2.
The invention also provides a preparation method of the positive electrode material, which comprises the following steps:
a) Mixing a precursor A containing Me 3O4 doped with Al and Z with a lithium salt and optionally a compound containing M element, and performing first calcination to obtain the lithium cobaltate matrix material.
B) Preparing at least one metal compound as a preparation raw material of the innermost coating layer, mixing with the lithium cobaltate matrix material obtained in the step a, and performing secondary calcination to obtain a substance B;
c) B, preparing a fast ion conductor LATP/LLZO as a preparation raw material of a first coating layer, mixing with the substance B obtained in the step B, and performing third calcination to obtain a substance C;
d) Preparing LiCoPO 4 as a preparation raw material of the second coating layer, mixing with the substance C obtained in the step C, and performing fourth calcination to obtain the positive electrode material with the multilayer coating structure.
According to the preparation method of the invention, in the step a), the cobalt precursor Me 3O4 containing the doping of Al and Z is prepared by the following method:
1) Preparing a cobalt source, an Al element-containing compound and a Z element-containing compound into an aqueous solution;
2) Mixing the aqueous solution, the complex and the precipitant for reaction to obtain carbonate MeCO 3 containing Al and Z doped cobalt.
3) Calcining the obtained MeCO 3 at high temperature to obtain doped Me 3O4;
according to the preparation method of the cobalt precursor Me 3O4 containing the doping of Al and Z, in the step 1),
In one example, the cobalt source comprises at least one of cobalt acetate, cobalt oxalate, cobalt nitrate, cobalt sulfate, cobalt chloride, and cobalt hydroxide;
in one example, the compound containing Al element includes at least one of oxide, chloride, hydroxide, carbonate, sulfate, nitrate, oxalate, acetate containing Al element;
in one example, the compound containing the Z element includes at least one of an oxide, chloride, hydroxide, carbonate, sulfate, nitrate, oxalate, acetate containing the Z element;
In one example, the molar ratio of the cobalt source, the Al element-containing compound, and the Z element-containing compound is such that the molar ratio of Co, al, Z is 1-a-b: a: b, wherein 0<a.ltoreq.0.2, 0.ltoreq.0.2;
In one example, the concentration of the cobalt source in the aqueous solution is 0.8-3.8mol/L.
According to the preparation method of the cobalt precursor Me 3O4 containing the doping of Al and Z, in the step 2),
In one example, the complexing agent comprises ammonia, the concentration of which is 20% to 25%;
In one example, the precipitating agent includes a soluble base including one of Na 2CO3、NH4HCO3、(NH4)2CO3, etc.;
in one example, the mass ratio of the complex to the precipitant is 2:1 to 1:1;
in an example, the concentration of the precipitant in the mixed system is 0.8-3.8 mol/L;
In one example, the temperature of the reaction is 30-80 ℃, and the time of the reaction is 10-20 hours;
In one example, the aqueous solution, the complex solution, and the precipitant solution are mixed to cause a complex precipitation reaction.
According to the preparation method of the cobalt precursor Me 3O4 containing the doping of Al and Z, in the step 3), in an example, the temperature of sintering Me 3O4 by the MeCO 3 is 500-1000 ℃ and the sintering time is 2-10 h.
According to the preparation method of the positive electrode material, in the step a), the temperature of the first calcination is 820-1000 ℃, and the time of the first calcination is 8-12 hours. The first calcination is performed under an air atmosphere.
According to the preparation method of the positive electrode material, in the step a), the compound containing the M element comprises at least one of oxide, chloride, hydroxide, carbonate, sulfate, nitrate, oxalate and acetate of M.
According to the preparation method of the positive electrode material, in the step a), the lithium salt comprises at least one of lithium hydroxide, lithium nitrate, lithium carbonate, lithium oxalate, lithium acetate, lithium oxide and lithium citrate.
According to the preparation method of the positive electrode material, in the step a), the molar ratio of the lithium salt, the compound containing M element and the precursor A of Me 3O4 doped with Al and A is that the molar ratio of Li, me and M is x to z to y, wherein x is more than or equal to 0.95 and less than or equal to 1.05,0 and y is more than or equal to 0.2, and z is more than or equal to 0.8 and less than or equal to 1.
According to the preparation method of the positive electrode material, in the step b), the temperature of the second calcination is 850-1070 ℃, and the time of the second calcination is 8-12 hours. The second calcination is performed under an air atmosphere.
According to the preparation method of the positive electrode material, in the step b), the metal compound comprises metal oxide, metal fluoride, metal borate compound and metal phosphate compound.
In one example, the metal fluoride includes one or more of AlF 3、Li3F、MgF2、LaF3.
In one example, the metal oxide includes one or more of Al2O3、TiO2、ZrO2、SrO、MgO2、Y2O3、La2O3.
In one example, the metal borate compound includes AlBO 3.
In one example, the metal phosphate compound includes one or both of AlPO 4、Li3PO4, and the like.
According to the preparation method of the positive electrode material, in the step c), the temperature of the third calcination is 800-1000 ℃, and the time of the third calcination is 6-9 hours. The third calcination is performed under an air atmosphere.
According to the preparation method of the positive electrode material, in the step d), the temperature of the fourth calcination is 700-1000 ℃, and the time of the fourth calcination is 3-10 hours. The fourth calcination is performed under an air atmosphere.
A second aspect of the invention provides a positive electrode sheet comprising the positive electrode material of the first aspect of the invention.
In the present invention, the positive electrode sheet further includes a conductive agent and a binder.
In an example, the positive plate comprises the following components in percentage by mass: 70 to 99 weight percent of positive electrode material, 0.5 to 15 weight percent of conductive agent and 0.5 to 15 weight percent of binder.
In an example, the positive plate comprises the following components in percentage by mass: 80-98 wt% of positive electrode material, 1-10 wt% of conductive agent and 1-10 wt% of binder.
In one example, the conductive agent includes at least one of conductive carbon black, acetylene black, ketjen black, conductive graphite, conductive carbon fiber, carbon nanotube, metal powder, and carbon fiber.
In one example, the binder includes at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), and lithium Polyacrylate (PAALi).
A third aspect of the invention provides a battery comprising an electrolyte and the positive electrode material according to the first aspect of the invention and/or the positive electrode sheet according to the second aspect of the invention.
In the present invention, the electrolyte includes an organic solvent, a conductive lithium salt, and an additive.
In one example, the additive includes at least one of nitrile compound, vinylene carbonate, 1, 3-Propane Sultone (PS), fluoroethylene carbonate (FEC).
In one example, the additive includes fluoroethylene carbonate and/or 1, 3-propane sultone. In yet another example, the additive includes fluoroethylene carbonate and 1, 3-propane sultone.
When fluoroethylene carbonate (FEC) and 1, 3-Propane Sultone (PS) are included in the electrolyte, the cycle life of the battery under a high voltage system can be significantly improved, probably due to the following reasons: the reduction potential of PS is higher than that of a carbonic ester solvent, so that a chemically and electrochemically stable SEI film can be formed on the surface of a negative electrode by means of preferential reduction, further decomposition of electrolyte components is effectively inhibited, and the high-temperature cycle performance of a battery can be effectively improved, but more inorganic components in the SEI film formed by PS can cause larger impedance, so that Li + transmission is blocked, normal-temperature dynamics are deteriorated, and the rate performance is deteriorated. The FEC is compact in film formation and does not increase impedance, so that the normal temperature dynamic performance can be effectively improved, but the FEC can be decomposed into HF at high temperature to dissolve an SEI film, so that the high temperature cycle performance is deteriorated, the FEC and PS can be effectively complemented when combined for use, the stability of the SEI film at high temperature can be ensured while the impedance of the SEI film is reduced, the electrolyte component is prevented from being further decomposed, the impedance of a battery can be further reduced when the FEC and PS are combined for use, and the cycle performance of the battery comprising the positive electrode material at high temperature can be improved.
In order to further reduce the resistance of the battery, avoid capacity loss and better improve the cycle performance of the battery, in one example, the fluoroethylene carbonate is contained in an amount of 0.1 wt% to 10 wt% (e.g., 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5wt%, 6wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%) and the 1, 3-propane sultone is contained in an amount of 0.1 wt% to 6wt% (e.g., 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5wt%, 6 wt%) based on the total weight of the electrolyte. The relative contents of PS and FEC relative to the total mass of the electrolyte are controlled respectively, so that the impedance of the SEI film can be controlled at a relatively low level, the SEI film is prevented from being dissolved, the stability of the electrolyte is ensured, and the electrolyte is used together with the anode material, so that the loss of electrolyte components can be further reduced, and the cycle performance of the battery is further improved.
In one example, the organic solvent includes a linear carbonate and/or a linear carboxylate and a cyclic carbonate.
In one example, the cyclic carbonate includes at least one of ethylene carbonate and propylene carbonate, the linear carbonate includes at least one of dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate, and the linear carboxylate includes at least one of ethyl propionate, propyl propionate, and propyl acetate.
In one example, the linear carbonate and/or the linear carboxylate is present in an amount of 60% to 80% by volume and the cyclic carbonate is present in an amount of 20% to 40% by volume, based on the total volume of the organic solvent. When the organic solvent contained in the electrolyte contains specific content of linear carbonate and/or linear carboxylate and cyclic carbonate, side reaction between the electrolyte and the positive electrode material under high voltage can be reduced, and interface impedance of the battery can be reduced, so that electrochemical performance and cycle performance of the battery under high voltage can be further improved.
In one example, the conductive lithium salt includes at least one of lithium hexafluorophosphate, lithium bis-fluorosulfonyl imide, lithium bis-trifluoromethanesulfonyl imide.
In order to further suppress side reactions such as decomposition of the electrolyte on the surface of the positive electrode material and improve the cycle performance of the battery, a nitrile compound may be further included in the additive of the electrolyte. In one example, the nitrile compound includes at least one of adiponitrile, succinonitrile, 1, 2-bis (cyanoethoxy) ethane. The nitrile compound can form a protective film on the surface of the positive electrode material and effectively inhibit the dissolution of transition metals.
In the present invention, the battery further includes a negative electrode sheet and a separator.
In one example, the negative electrode sheet includes a negative electrode active material, a conductive agent, and a binder.
In an example, the negative plate comprises the following components in percentage by mass: 70 to 99wt% of negative electrode active material, 0.5 to 15wt% of conductive agent, and 0.5 to 15wt% of binder.
In an example, the negative plate comprises the following components in percentage by mass: 80 to 98 weight percent of negative electrode active material, 1 to 10 weight percent of conductive agent and 1 to 10 weight percent of binder.
In one example, the negative active material includes one or a combination of several of artificial graphite, natural graphite, hard carbon, mesophase carbon microspheres, lithium titanate, silicon carbon, and silicon oxide.
In one example, the separator used is a polypropylene-based material, or a rubberized separator coated on one or both sides with a ceramic on the basis of this.
The invention also provides application of the positive electrode material, which is used for a lithium ion battery of a high-voltage system.
In one example, the electrochemical performance of the positive electrode material assembled lithium ion battery was tested at a voltage of ≡4.53V (vs. graphite negative electrode). The test result shows that the gram capacity of the positive electrode active material can reach more than 193mAh/g, and the positive electrode active material has excellent cycle performance.
In the present invention, the numerical expressions "first", "second", "third", etc. are used only to distinguish different substances or modes of use, and do not represent differences in order.
The present invention will be described in detail by examples. The described embodiments of the invention are only some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The experimental methods used in the following examples are all conventional methods unless otherwise specified; the reagents, materials, etc. used in the examples described below are commercially available unless otherwise specified.
Example group I
The positive electrode material prepared by the invention is described.
Example I-1
The chemical formula of the positive electrode matrix material is Li 1.03Co0.975Al0.02Mg0.002Zr0.002Ti0.001O2, the first coating layer is LLZO, the thickness is 150nm, the coating layer accounts for 0.5% of the weight of the positive electrode matrix material, the coating layer is LiCoPO 4, the coating layer accounts for 0.5% of the weight of the positive electrode matrix material, and the thickness is 200nm;
The preparation method of the positive electrode material comprises the following steps:
(1) The CoSO 4、Al2(SO4)3、MgSO4 is dissolved by deionized water and is configured to be mole ratio Co: mixed salt solution of mg=97.8:2:0.2, and concentration of Co 2+ in the mixed salt solution is 1.25mol/L; preparing complexing agent solution by using concentrated ammonia water and distilled water according to a volume ratio of 1:10; 1.2mol/L sodium carbonate solution is selected as a precipitant solution; injecting 1/3 of the solvent of the precipitant solution into the reaction kettle, continuously injecting the mixed salt solution, the complexing agent solution and the precipitant solution into the reaction kettle to react in a parallel flow control flow mode under the strong stirring effect and the protection of inert gas, simultaneously stirring at the speed of not more than 200L/h, controlling the pH value of the reaction system to be 8-12, and controlling the temperature of the reaction kettle to be 70-80 ℃ in the reaction process; monitoring the concentration of liquid phase ions doped with elements Al, mg and Co in the reaction system in real time in the reaction process; performing centrifugal filtration after continuously reacting and repeatedly crystallizing for 4 times to obtain a Co 3 precursor cobalt salt doped with Al and Mg, and sintering at a high temperature of 900 ℃ for 8 hours to obtain a Co 3O4 precursor doped with Al and Mg;
(2) Weighing lithium carbonate according to a molar ratio of Li to Co=103:99.5, stirring and mixing the lithium carbonate and the Al-Mg doped Co 3O4 precursor in the step (1) uniformly, placing the mixture in a muffle furnace at 1070 ℃ for 12h, and then crushing the sintered product to obtain Al-Mg Co-doped lithium cobalt oxide Li 1.03Co0.988Al0.01Mg0.002O2;
(3) Molar ratio Co: ti: and (2) weighing titanium dioxide, zirconium oxide and Al-Mg co-doped lithium cobaltate in the step (2) by Zr=97.5:0.1:0.2, stirring and mixing uniformly, placing the mixture in a muffle furnace at 950 ℃ for 12 hours, and then crushing the sintered product to obtain a matrix lithium cobaltate material Li 1.03Co0.975Al0.02Mg0.002Zr0.002Ti0.001O2.
(4) And (3) uniformly stirring and mixing LLZO and the matrix lithium cobaltate material in the step (3) according to the weight ratio of 0.5:100, placing the mixture in a muffle furnace, sintering at 850 ℃ for 8 hours, then crushing the sintered product to obtain a transition product, uniformly stirring and mixing the transition product and LiCoPO 4 according to the mass ratio of 100:0.5, placing the mixture in the muffle furnace, and sintering at 875 ℃ for 8 hours to obtain the anode material with a multilayer special coating structure, wherein D v50 is 15.5 mu m.
Example I-2
The chemical formula of the positive electrode matrix material is Li 1.03Co0.98Al0.01Zr0.002Y0.005Mg0.002Ti0.001O2, the first coating layer is LLZO, the first coating layer accounts for 0.5% of the matrix material in weight ratio, and the thickness is 150nm; the second coating layer on the outer surface layer is coated by LiCoPO 4, the weight ratio of the second coating layer to the substrate material is 1%, and the thickness is 350nm;
The preparation method of the positive electrode material comprises the following steps:
(1) The CoSO 4、Al2(SO4)3、MgSO4 is dissolved by deionized water and is configured to be mole ratio Co: mixed salt solution of mg=98.8:1:0.2, and concentration of Co 2+ in the mixed salt solution is 1.25mol/L; preparing complexing agent solution by using concentrated ammonia water and distilled water according to a volume ratio of 1:10; 1.2mol/L sodium carbonate solution is selected as a precipitant solution; injecting 1/3 of the solvent of the precipitant solution into the reaction kettle, continuously injecting the mixed salt solution, the complexing agent solution and the precipitant solution into the reaction kettle to react in a parallel flow control flow mode under the strong stirring effect and the protection of inert gas, simultaneously stirring at the speed of not more than 200L/h, controlling the pH value of the reaction system to be 8-12, and controlling the temperature of the reaction kettle to be 70-80 ℃ in the reaction process; monitoring the concentration of liquid phase ions doped with elements Al, mg and Co in the reaction system in real time in the reaction process; performing centrifugal filtration after continuously reacting and repeatedly crystallizing for 4 times to obtain a Co 3 precursor cobalt salt doped with Al and Mg, and sintering at a high temperature of 900 ℃ for 8 hours to obtain a Co 3O4 precursor doped with Al and Mg;
(2) Lithium carbonate is weighed according to the molar ratio of Li to Co=103 to 99.5, and according to the molar ratio of Co: y=98.3: 0.5, weighing yttrium oxide and the Al-Mg doped Co 3O4 precursor in the step (1), stirring and mixing uniformly, placing in a muffle furnace at 1070 ℃ for 12 hours, and then crushing the sintered product to obtain Al-Mg-Y Co-doped lithium cobalt oxide Li 1.03Co0.983Al0.01Mg0.002Y0.005O2;
(3) The molar ratio Co to Ti: and (2) weighing titanium dioxide and zirconium oxide, uniformly stirring and mixing the titanium dioxide and the zirconium oxide with the Al-Mg-Y co-doped lithium cobalt oxide in the step (2), placing the mixture in a muffle furnace at 950 ℃ for 12 hours, and then crushing the sintered product to obtain the matrix lithium cobalt oxide material Li 1.03Co0.98Al0.01Mg0.002Y0.005Zr0.002Ti0.001O2.
(4) And (3) uniformly stirring and mixing LLZO and the matrix material in the step (3) according to the weight ratio of 0.5:100, placing the mixture in a muffle furnace, sintering at 850 ℃ for 8 hours, then crushing the sintered product to obtain a transition product, uniformly stirring and mixing the transition product and LiCoPO 4 according to the mass ratio of 100:1, placing the mixture in the muffle furnace, and sintering at 875 ℃ for 8 hours to obtain the anode material with a multilayer special coating structure, wherein D v50 is 15.5 mu m.
Example I-3
The chemical formula of the positive electrode matrix material is Li 1.03Co0.977Al0.015Y0.005Mg0.002Ti0.001O2, the first coating layer is LLZO, the first coating layer accounts for 0.8% of the matrix material in weight ratio, and the thickness is 250nm; the second coating layer on the outer surface layer is coated by LiCoPO 4, the weight ratio of the second coating layer to the substrate material is 0.8%, and the thickness of the second coating layer is 300nm;
The preparation method of the positive electrode material comprises the following steps:
(1) The CoSO 4、Al2(SO4)3、MgSO4 is dissolved by deionized water and is configured to be mole ratio Co: mixed salt solution of mg=98.3:1.5:0.2, and concentration of Co 2+ in the mixed salt solution is 1.25mol/L; preparing complexing agent solution by using concentrated ammonia water and distilled water according to a volume ratio of 1:10; 1.2mol/L sodium carbonate solution is selected as a precipitant solution; injecting 1/3 of the solvent of the precipitant solution into the reaction kettle, continuously injecting the mixed salt solution, the complexing agent solution and the precipitant solution into the reaction kettle to react in a parallel flow control flow mode under the strong stirring effect and the protection of inert gas, simultaneously stirring at the speed of not more than 200L/h, controlling the pH value of the reaction system to be 8-12, and controlling the temperature of the reaction kettle to be 70-80 ℃ in the reaction process; monitoring the concentration of liquid phase ions doped with elements Al, mg and Co in the reaction system in real time in the reaction process; performing centrifugal filtration after continuously reacting and repeatedly crystallizing for 4 times to obtain a Co 3 precursor cobalt salt doped with Al and Mg, and sintering at a high temperature of 900 ℃ for 8 hours to obtain a Co 3O4 precursor doped with Al and Mg;
(2) Lithium carbonate is weighed according to the molar ratio of Li to Co=103 to 99.5, and according to the molar ratio of Co: y=97.8: 0.5, weighing yttrium oxide and the Al-Mg doped Co 3O4 precursor in the step (1), stirring and mixing uniformly, placing in a muffle furnace at 1070 ℃ for 12 hours, and then crushing the sintered product to obtain Al-Mg-Y Co-doped lithium cobalt oxide Li 1.03Co0.978Al0.015Mg0.002Y0.005O2;
(3) And (3) weighing titanium dioxide according to a molar ratio of Co to Ti=97.7:0.1, stirring and mixing uniformly with the Al-Mg-Y Co-doped lithium cobalt oxide obtained in the step (2), placing in a muffle furnace at 950 ℃ for 12 hours, and then crushing the sintered product to obtain the matrix lithium cobalt oxide anode material Li 1.03Co0.977Al0.015Mg0.002Y0.005Ti0.001O2.
(4) And (3) uniformly stirring and mixing LLZO and the matrix material in the step (3) according to the weight ratio of 0.8:100, placing the mixture in a muffle furnace, sintering the mixture at 850 ℃ for 8 hours, then crushing the sintered product to obtain a transition product, uniformly stirring and mixing the transition product and LiCoPO 4 according to the mass ratio of 100:0.8, placing the mixture in the muffle furnace, and sintering the mixture at 875 ℃ for 8 hours to obtain the anode material with a multilayer special coating structure, wherein D v50 is 15.5 mu m.
Example I-4
The chemical formula of the positive electrode matrix material is Li 1.03Co0.975Al0.02Y0.003Mg0.001Ti0.001O2, the first coating layer is LLZO, the first coating layer accounts for 0.6% of the matrix material by weight, and the thickness is 200nm; the second coating layer of the outer surface layer adopts LiCoPO 4 to coat and account for 0.7 percent of the weight of the matrix material, and the thickness is 280nm;
The preparation method of the positive electrode active material comprises the following steps:
(1) The CoSO 4、Al2(SO4)3、MgSO4 is dissolved by deionized water and is configured to be mole ratio Co: mixed salt solution of mg=97.9:2:0.1, and concentration of Co 2+ in the mixed salt solution is 1.25mol/L; preparing complexing agent solution by using concentrated ammonia water and distilled water according to a volume ratio of 1:10; 1.2mol/L sodium carbonate solution is selected as a precipitant solution; injecting 1/3 of the solvent of the precipitant solution into the reaction kettle, continuously injecting the mixed salt solution, the complexing agent solution and the precipitant solution into the reaction kettle to react in a parallel flow control flow mode under the strong stirring effect and the protection of inert gas, simultaneously stirring at the speed of not more than 200L/h, controlling the pH value of the reaction system to be 8-12, and controlling the temperature of the reaction kettle to be 70-80 ℃ in the reaction process; monitoring the concentration of liquid phase ions doped with elements Al, mg and Co in the reaction system in real time in the reaction process; performing centrifugal filtration after continuously reacting and repeatedly crystallizing for 4 times to obtain a Co 3 precursor cobalt salt doped with Al and Mg, and sintering at a high temperature of 900 ℃ for 8 hours to obtain a Co 3O4 precursor doped with Al and Mg;
(2) Lithium carbonate is weighed according to the molar ratio of Li to Co=103 to 99.5, and according to the molar ratio of Co: y=97.6: 0.3, weighing yttrium oxide and the Al-Mg doped Co 3O4 precursor in the step (1), uniformly stirring and mixing, placing in a muffle furnace at 1070 ℃ for 12 hours, and then crushing the sintered product to obtain Al-Mg-Y Co-doped lithium cobalt oxide Li 1.03Co0.976Al0.02Mg0.001Y0.003O2;
(3) And (3) weighing titanium dioxide according to a molar ratio of Co to Ti=97.5:0.1, stirring and mixing uniformly with the Al-Mg-Y Co-doped lithium cobalt oxide obtained in the step (2), placing in a muffle furnace at 950 ℃ for 12 hours, and then crushing the sintered product to obtain the matrix lithium cobalt oxide anode material Li 1.03Co0.975Al0.02Mg0.001Y0.003Ti0.001O2.
(4) Uniformly stirring and mixing LLZO and the matrix material in the step (3) according to the weight ratio of 0.6:100, placing the mixture in a muffle furnace, sintering the mixture at 850 ℃ for 8 hours, then crushing the sintered product to obtain a transition product, uniformly stirring and mixing the transition product and LiCoPO 4 according to the mass ratio of 100:0.7, placing the mixture in the muffle furnace, and sintering the mixture at 875 ℃ for 8 hours to obtain the anode material with a multilayer special coating structure, wherein D v50 is 15.5 mu m; in addition, the coating layer distribution state of the LLZO is punctiform coated, and the second coating layer LLZO occupies 60% of the total coverage area of the first coating layer LiCoPO 4.
Examples I-5 to I-20
In example I-5-I-20, the preparation method of the cathode material was the same as in example I-4, and the description thereof was omitted herein, except that LLZO and LiCoPO 4 were used as weight percentages of the total mass of the lithium cobaltate matrix material, the corresponding LLZO and LiCoPO 4 were weighed and coated according to the weight percentages listed in table 1, and the thicknesses (nm) of the first coating layer and the second coating layer were measured, respectively, and are uniformly recorded in table 1.
TABLE 1
Further, by observing the SEM images of the specific positive electrode material particles prepared in the above examples, the distribution states of the second coating layers of the positive electrode materials of examples I-9 to I-13 and the percentage (%) of the second coating layer to the total coverage area of the first coating layer were recorded, and are collectively recorded in table 2.
TABLE 2
Comparative example I-1
The positive electrode material was the same as the matrix lithium cobaltate material of example I-4, and the preparation method was also the same as example I-4, and will not be repeated here, except that the surface layer was not coated with LLZO and LiCoPO 4.
Comparative example I-2
The positive electrode material was the same as the matrix lithium cobaltate material of example I-4, and the preparation method was also the same as example I-4, and will not be repeated here, except that the surface layer was coated with LLZO only, and the amount of LLZO coating was 0.6% by weight of the lithium cobaltate matrix material.
Comparative example I-3
The positive electrode material was the same as the matrix lithium cobaltate material of example I-4, and the preparation method was the same as example I-4, and the description was omitted here, except that the surface layer was coated with LiCoPO 4 only, and LiCoPO 4 was used in an amount of 0.7% by weight of lithium cobaltate.
Comparative example I-4
The positive electrode material was the same as the matrix lithium cobaltate material of example I-4, and was different from example I-4 in that LLZO and LiCoPO 4 were mixed and coated together, wherein LLZO was 0.6% by weight of the matrix active material, and the outer surface layer was 0.7% by weight of the matrix active material coated with LiCoPO 4, and the mixture was sintered at 875 ℃ for 8 hours to obtain a mixed coated positive electrode material.
Examples I-21
The positive electrode material was the same as the matrix lithium cobalt oxide material of example I-4, and the preparation method was also the same as that of example I-4, except that the first coating layer coating material was changed to LATP, which was not repeated here.
Examples I-22
The positive electrode material was the same as the matrix lithium cobalt oxide material of example I-4, and the preparation method thereof was also the same as that of example I-4, except that the first coating layer coating material was LLZTO, which was not repeated here.
Examples I-23 to I-28
The positive electrode material was the same as the matrix lithium cobaltate material of example I-4, and will not be repeated here, except that the preparation method of the positive electrode material was adjusted so that D v50 of the positive electrode material was changed, see in particular table 3.
TABLE 3 Table 3
| Group of | Dv50/μm |
| Examples I-23 | 4.5 |
| Examples I to 24 | 24.5 |
| Examples I-25 | 3.5 |
| Examples I-26 | 29 |
| Examples I-27 | 40 |
| Examples I-28 | 1 |
Preparation example I group
For illustrating the electrolyte prepared by the invention
Preparation example I-1
The electrolyte is prepared according to the following steps:
In an argon atmosphere glove box with a water content of <10ppm, ethylene Carbonate (EC), propylene Carbonate (PC), diethyl carbonate (DEC), propyl Propionate (PP) and dimethyl carbonate (DMC) were mixed according to a mass ratio of 20:10:10:10:50, uniformly mixing to obtain a nonaqueous solvent; liPF 6 of 14.5% based on the total mass of the electrolyte was added to the above nonaqueous solvent, stirred until completely dissolved, 3% by weight of 1, 3-Propane Sultone (PS) was added, 6% by weight of fluoroethylene carbonate (FEC) was added, and 5% by weight of nitrile compound was added to obtain an electrolyte.
Preparation examples I-2 to I-6 were conducted with reference to preparation example I-1 except that: the quality of FEC and the quality of PS added to the electrolyte were changed as shown in table 4.
TABLE 4 Table 4
| Preparation example | FEC/wt% | PS/wt% |
| I-1 | 6 | 3 |
| I-2 | 10 | 6 |
| I-3 | 4 | 2 |
| I-4 | 6 | - |
| I-5 | - | 3 |
| I-6 | - | - |
| I-7 | 0.2 | 0.2 |
| I-8 | 12 | 3 |
| I-9 | 6 | 8 |
| I-10 | 0.05 | 3 |
| I-11 | 6 | 0.05 |
Note that: the "-" in table 4 indicates that no addition was made.
Example group II
For use in the preparation of the cells of the present invention.
Example II-1
The battery was prepared according to the following steps:
(1) Preparation of positive electrode sheet
Uniformly mixing the positive electrode material obtained in the embodiment I-1, a conductive agent and polyvinylidene fluoride (PVDF) according to a certain mass ratio, and adding N-methyl pyrrolidone, wherein the solid content is 75wt%, so as to form positive electrode slurry; coating the positive electrode slurry on the surface of an aluminum foil, and drying and cold pressing to obtain a positive electrode plate;
(2) Preparation of negative electrode sheet
Mixing artificial graphite (particle size Dv50:13+ -1 μm, graphitization degree 94+ -0.5%, secondary particles with single particles, wherein the mass ratio of the secondary particles is 50%), acetylene black, styrene Butadiene Rubber (SBR) and sodium carboxymethylcellulose (CMC-Na) according to the mass ratio of 95:2:2:1, uniformly mixing, adding deionized water, wherein the solid content is 45wt%, forming negative electrode slurry, coating the negative electrode slurry on the surface of a copper foil, drying, and cold pressing to obtain a negative electrode plate;
(3) Preparation of a cell
And (3) stacking the positive plate prepared in the step (1), the isolating film (PE porous polymer film) and the negative plate prepared in the step (2) in sequence, enabling the isolating film to be positioned between the positive plate and the negative plate to play a role of isolation, winding to obtain a bare cell, placing the bare cell into an outer packaging foil, drying, injecting the electrolyte prepared in the preparation example I-1 of the group I, and carrying out vacuum packaging, standing, formation and shaping to obtain the battery. See in particular table 5.
Examples II-2 to II-38, comparative examples II-1 to II-4
Reference is made to example II-1, except that the positive electrode sheet was made of a different positive electrode material and the electrolyte was different, see in particular table 5.
TABLE 5
| Group of | Positive electrode material | Electrolyte solution |
| Example II-1 | Example I-1 | Preparation example I-1 |
| Example II-2 | Example I-2 | Preparation example I-1 |
| Example II-3 | Example I-3 | Preparation example I-1 |
| Example II-4 | Example I-4 | Preparation example I-1 |
| Example II-5 | Example I-5 | Preparation example I-1 |
| Examples II to 6 | Example I-6 | Preparation example I-1 |
| Examples II to 7 | Example I-7 | Preparation example I-1 |
| Examples II to 8 | Example I-8 | Preparation example I-1 |
| Examples II to 9 | Examples I-9 | Preparation example I-1 |
| Examples II to 10 | Examples I to 10 | Preparation example I-1 |
| Examples II to 11 | Example I-11 | Preparation example I-1 |
| Examples II to 12 | Examples I-12 | Preparation example I-1 |
| Examples II to 13 | Examples I-13 | Preparation example I-1 |
| Examples II to 14 | Examples I to 14 | Preparation example I-1 |
| Examples II to 15 | Examples I-15 | Preparation example I-1 |
| Examples II to 16 | Examples I-16 | Preparation example I-1 |
| Examples II to 17 | Examples I to 17 | Preparation example I-1 |
| Examples II to 18 | Examples I-18 | Preparation example I-1 |
| Examples II to 19 | Examples I to 19 | Preparation example I-1 |
| Examples II to 20 | Examples I to 20 | Preparation example I-1 |
| Comparative example II-1 | Comparative example I-1 | Preparation example I-1 |
| Comparative example II-2 | Comparative example I-2 | Preparation example I-1 |
| Comparative example II-3 | Comparative example I-3 | Preparation example I-1 |
| Comparative example II-4 | Comparative example I-4 | Preparation example I-1 |
| Examples II to 21 | Examples I-21 | Preparation example I-1 |
| Examples II to 22 | Examples I-22 | Preparation example I-1 |
| Examples II to 23 | Examples I-23 | Preparation example I-1 |
| Examples II to 24 | Examples I to 24 | Preparation example I-1 |
| Examples II to 25 | Examples I-25 | Preparation example I-1 |
| Examples II to 26 | Examples I-26 | Preparation example I-1 |
| Examples II to 27 | Examples I-27 | Preparation example I-1 |
| Examples II to 28 | Examples I-28 | Preparation example I-1 |
| Examples II to 29 | Example I-4 | PREPARATION EXAMPLE I-2 |
| Examples II to 30 | Example I-4 | Preparation example I-3 |
| Examples II to 31 | Example I-4 | PREPARATION EXAMPLE I-4 |
| Examples II to 32 | Example I-4 | PREPARATION EXAMPLE I-5 |
| Examples II to 33 | Example I-4 | PREPARATION EXAMPLE I-6 |
| Examples II to 34 | Example I-4 | PREPARATION EXAMPLE I-7 |
| Examples II to 35 | Example I-4 | PREPARATION EXAMPLE I-8 |
| Examples II to 36 | Example I-4 | PREPARATION EXAMPLE I-9 |
| Examples II to 37 | Example I-4 | Preparation example I-10 |
| Examples II to 38 | Example I-4 | PREPARATION EXAMPLE I-11 |
The lithium ion batteries provided in examples and comparative examples in table 5 include a positive electrode sheet, a negative electrode sheet, a separator interposed between the positive electrode sheet and the negative electrode sheet, and an electrolyte, the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer distributed on the positive electrode current collector, the positive electrode active material layer includes a positive electrode material, a binder and a conductive agent, and the battery of the present invention adopts a graphite negative electrode with a charge cutoff voltage of 4.53 to 4.55V. Wherein, as shown in fig. 1, which is an SEM image of the positive electrode material used in the embodiment I-4 in the embodiment II-4, and as shown in fig. 2, 3 and 4, which are an SEM image of the CP cross section of the positive electrode material used in the embodiment I-4 in the embodiment II-4 and an EDS image of La element and P element surface scanning with the same cross section, respectively, it can be observed from fig. 3 that La element is distributed on the subsurface layer of the positive electrode material particles, which indicates that LLZO forms a relatively uniform coating layer on the subsurface layer of the positive electrode material; as can be seen from fig. 4, the P element is distributed in the outermost layer of the cathode material particles, indicating that LiCoPO 4 forms a good coating layer in the outermost layer of the cathode material.
The lithium ion batteries provided in examples and comparative examples in table 5 were subjected to the following test, and the results obtained are shown in tables 6 and 7.
(1) First effect of battery
The first efficiency test procedure used was:
using the above battery, at 25 ℃, constant current charge was performed to 4.53V at a charge-discharge rate of 0.2C, constant voltage charge was performed to 4.53V at a charge rate of 0.05C, and discharge was performed to 3.0V at a discharge rate of 0.2C, and first charge and discharge capacities were counted, with first efficiency= (first discharge capacity)/(first charge capacity) ×100%.
(2) Gram capacity of battery
The gram capacity test procedure used was:
Using the above battery, the discharge capacity was counted as gram capacity= (discharge capacity)/(positive electrode active material weight) (unit: mAh/g) at 25 ℃ by constant-current charging to 4.53V at a charge/discharge rate of 0.2C, constant-voltage charging to 4.53V at a charge rate of 0.05C, and then discharging to 3.0V at a discharge rate of 0.2C.
(3) Cycle performance of battery
The cycle performance test procedure used was:
Using the above battery, the battery was charged to 4.53V at a constant current at 25 ℃ at a charge rate of 1C, charged to 4.53V at a constant voltage at a charge rate of 0.05C, and discharged to 3.0V at a discharge rate of 1C, and this charge-discharge cycle was repeated 500 times, and the discharge capacity at the first cycle and the discharge capacity at the 500 th cycle were measured to determine the capacity retention after the cycle, i.e., the capacity retention after the cycle= (discharge capacity at the 500 th cycle)/(discharge capacity at the first cycle)/(100%).
(4) DCR of battery
The battery DCR test method used is specifically as follows: a) Standing at 25deg.C for 4 hr, fully charging to 4.53V at 0.7deg.C, and standing for 10min at off-current of 0.025C; b) Discharge to 3.4V at 25 ℃ with 0.1C (this capacity is the reference capacity for SOC calculation); c) Then the capacitor is fully charged to 4.53V by 0.7C of the reference capacity, and the cut-off current is 0.025C; d) 30% of the capacity (30% of the corresponding reference capacity) was discharged with 0.1C of the reference capacity, and samples were recorded at 1 min; e) 1C discharge 1S of rated capacity (samples recorded in 20 ms); f) The value method of the 70% SOC DCR comprises the following steps: 70% soc dcr= (V 1-V2)/(1C-0.1C) ×1000000) (unit: mΩ), wherein 0.1C discharge end voltage was taken as V 1 (i.e., 70% soc-V 1) and 1C discharge end voltage was taken as V 2 (i.e., 70% soc-V 2).
Table 6: performance data for lithium ion batteries of examples and comparative examples in table 5 under a 4.53V system
/>
Table 7: performance data for lithium ion batteries of examples and comparative examples in table 5 at 4.55V system
/>
As can be seen from the test results of tables 6 and 7: when the positive electrode material which is used as the positive electrode active material of the lithium ion battery and is coated by the LiCoPO 4 material with high voltage resistance is used as the first coating layer in combination and matched with the electrolyte used in the invention, the high gram capacity is exerted under a voltage system of 4.53V or more, no obvious loss is caused in gram capacity along with the increase of the coating amount, the cycle performance of the battery core under a high voltage system is very excellent, and the capacity retention rate after 500 times of cycle is at least 90 percent; the LLZO coating or LCPO coating alone has an improvement effect on high-temperature circulation, but the high-temperature performance is worse than that of the combined coating when the LLZO coating or LCPO coating is used as the outermost coating substance alone, and the DCR of the battery cell is obviously increased when the LCPO coating is used alone. When the positive electrode material of the present invention is used in combination with an electrolyte containing fluoroethylene carbonate or1, 3 propane sultone alone, there is also a certain improvement effect on the cycle, but the optimum improvement effect containing both additives cannot be achieved. When the positive electrode material of the present invention is used in combination with an electrolyte containing 1,3 propane sultone alone, the problem of DCR increase is caused by the high film formation resistance of 1,3 propane sultone.
In a word, the positive electrode material and the battery comprising the positive electrode material can enable the lithium ion battery to achieve higher energy density under high voltage and simultaneously give consideration to excellent cycle performance, and can meet the demand of people for thinning the lithium ion battery.
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 (12)
1. The positive electrode material is characterized by comprising a positive electrode base material, and a first coating layer and a second coating layer which are coated on the positive electrode base material; the first coating layer comprises a fast ion conductor substance; the second cladding layer includes LiCoPO 4.
2. The positive electrode material according to claim 1, wherein,
The DCR of the positive electrode material in a 70% SOC state is less than or equal to 55mΩ under 4.53V;
And/or, at 4.55V, DCR in a 70% SOC state is less than or equal to 60mΩ;
and/or the content of Li 2CO3 on the surface of the positive electrode material is less than or equal to 200ppm.
3. The positive electrode material according to claim 1, wherein a third coating layer including a metal compound is further coated between the positive electrode base material and the first coating layer.
4. The positive electrode material of claim 1, wherein the fast ionic conductor species comprises one or more of lithium aluminum titanium phosphate, lithium lanthanum zirconium oxide, lithium lanthanum zirconium tantalum oxide;
preferably, the fast ion conductor substance comprises lithium aluminum titanium phosphate and/or lithium lanthanum zirconium oxide.
5. The positive electrode material according to claim 1, wherein the first coating layer accounts for 0.03% -5%, preferably 0.05% -3% of the total mass of the positive electrode base material;
and/or, the second coating layer accounts for 0.05% -5% of the total mass of the positive electrode matrix material, and is preferably 0.08% -3%.
6. The positive electrode material according to claim 1, wherein the thickness of the first coating layer is 5nm-1000nm, preferably 20nm-800nm;
And/or the thickness of the second coating layer is 10nm-1000nm, preferably 20nm-800nm;
and/or the total thickness of the first coating layer and the second coating layer is 10nm-2000nm, preferably 40nm-1600nm.
7. The positive electrode material according to claim 1, wherein the second coating layer is coated on the first coating layer in a dot shape, and the second coating layer occupies 30% -100% of the total coverage area of the first coating layer.
8. The positive electrode material according to claim 1, wherein the particle diameter Dv 50 of the positive electrode material is 3 μm to 30 μm, preferably 4 μm to 25 μm.
9. The positive electrode material of claim 1, wherein the positive electrode base material comprises a lithium cobalt oxide material or a nickel cobalt manganese ternary material;
Preferably, the chemical formula of the lithium cobaltate material is Li xMezMyO2,Me＝Co1-a-bAlaZb, M is one or more of Al, mg, ti, zr, co, ni, mn, Y, la, sr, W, sc, Z is one or more of Y, la, mg, ti, zr, ni, mn, ce, x is more than or equal to 0.95 and less than or equal to 1.05,0 and less than or equal to y is more than or equal to 0.2, Z is more than or equal to 0.8 and less than or equal to 1, a is more than or equal to 0 and less than or equal to 0.2, and b is more than or equal to 0 and less than or equal to 0.2.
10. A positive electrode sheet, characterized in that the positive electrode sheet comprises the positive electrode material according to any one of claims 1 to 9.
11. A battery, characterized in that the battery comprises an electrolyte and the positive electrode material according to any one of claims 1-9 and/or the positive electrode sheet according to claim 10.
12. The battery of claim 11, wherein the electrolyte includes an additive therein, the additive including fluoroethylene carbonate and/or 1, 3-propane sultone;
Preferably, the fluoroethylene carbonate is contained in an amount of 0.1 to 10wt% and the 1, 3-propane sultone is contained in an amount of 0.1 to 6 wt% based on the total weight of the electrolyte;
And/or an organic solvent is included in the electrolyte, the organic solvent including linear carbonate and/or linear carboxylate and cyclic carbonate;
Preferably, the content of the linear carbonate and/or the linear carboxylate is 60 to 80% by volume and the content of the cyclic carbonate is 20 to 40% by volume based on the total volume of the organic solvent.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410075977.3A CN117913250A (en) | 2024-01-18 | 2024-01-18 | Positive electrode material, positive electrode plate and battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410075977.3A CN117913250A (en) | 2024-01-18 | 2024-01-18 | Positive electrode material, positive electrode plate and battery |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117913250A true CN117913250A (en) | 2024-04-19 |
Family
ID=90691912
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202410075977.3A Pending CN117913250A (en) | 2024-01-18 | 2024-01-18 | Positive electrode material, positive electrode plate and battery |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117913250A (en) |
-
2024
- 2024-01-18 CN CN202410075977.3A patent/CN117913250A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US11527752B2 (en) | Positive active material and preparation method thereof, electrochemical battery, battery module, battery pack, and apparatus | |
| CN110970602B (en) | Positive active material, positive pole piece and electrochemical device | |
| US11121367B2 (en) | Modified positive electrode active material, method for preparing the same and electrochemical energy storage device | |
| EP3588627B1 (en) | Lithium-ion battery | |
| CA2791187C (en) | Positive electrode active material for improving output, and lithium secondary battery comprising same | |
| WO2020134780A1 (en) | Positive electrode material, preparation method therefor, and use thereof | |
| CN110050366A (en) | For lithium secondary battery nickel hydroxide active material presoma, be used to prepare nickel hydroxide active material presoma method, by method prepare for the nickel hydroxide active material of lithium secondary battery and with the positive lithium secondary battery comprising nickel hydroxide active material | |
| CN110168785A (en) | Ni-based active material presoma and preparation method thereof, Ni-based active material and lithium secondary battery | |
| KR20130098372A (en) | Metal halide coatings on lithium ion battery positive electrode materials and corresponding batteries | |
| CN110729458B (en) | Positive active material, preparation method thereof, positive pole piece and lithium ion secondary battery | |
| KR20080031151A (en) | Nonaqueous electrolyte secondary battery and method for manufacturing same | |
| KR20120030774A (en) | Positive active material, method for preparing the same and lithium battery comprising the same | |
| WO2021249400A1 (en) | Positive electrode active material and electrochemical device comprising same | |
| CN113140731B (en) | All-solid-state lithium battery and preparation method thereof | |
| JP2014022294A (en) | Positive electrode active material for nonaqueous electrolyte secondary battery and method for producing the same | |
| CN115548329A (en) | Positive electrode active material and electrochemical device | |
| KR101776896B1 (en) | Cathode active material for lithium secondary battery and a method of making the same | |
| KR20230150863A (en) | Lithium-ion battery and power vehicles | |
| WO2023185548A1 (en) | Modified lithium manganese iron phosphate positive electrode material, and preparation method and application thereof | |
| CN117913250A (en) | Positive electrode material, positive electrode plate and battery | |
| CN110291667B (en) | Negative active material having high output characteristics and lithium secondary battery comprising the same | |
| CN114927693B (en) | Positive electrode active material, method for preparing same, electrochemical device, and electronic apparatus | |
| CN115312783B (en) | Coating method of lithium ion battery anode material | |
| CN116854148A (en) | Lithium cobaltate material, preparation method thereof, positive electrode material, positive electrode plate and lithium ion battery | |
| US20230411675A1 (en) | Lithium-ion battery |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination |