CN116885131A - Lithium-containing phosphate composite material and preparation method and application thereof - Google Patents
Lithium-containing phosphate composite material and preparation method and application thereof Download PDFInfo
- Publication number
- CN116885131A CN116885131A CN202310930945.2A CN202310930945A CN116885131A CN 116885131 A CN116885131 A CN 116885131A CN 202310930945 A CN202310930945 A CN 202310930945A CN 116885131 A CN116885131 A CN 116885131A
- Authority
- CN
- China
- Prior art keywords
- lithium
- containing phosphate
- ion conductor
- lithium ion
- source
- 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
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 title claims abstract description 299
- 229910052744 lithium Inorganic materials 0.000 title claims abstract description 299
- 229910019142 PO4 Inorganic materials 0.000 title claims abstract description 283
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 title claims abstract description 283
- 239000010452 phosphate Substances 0.000 title claims abstract description 283
- 239000002131 composite material Substances 0.000 title claims abstract description 195
- 238000002360 preparation method Methods 0.000 title claims description 18
- 239000000463 material Substances 0.000 claims abstract description 242
- 229910001416 lithium ion Inorganic materials 0.000 claims abstract description 223
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 claims abstract description 222
- 239000010416 ion conductor Substances 0.000 claims abstract description 181
- 239000011149 active material Substances 0.000 claims abstract description 142
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 80
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 79
- 239000007774 positive electrode material Substances 0.000 claims abstract description 12
- 238000005245 sintering Methods 0.000 claims description 67
- 239000000126 substance Substances 0.000 claims description 60
- 238000000034 method Methods 0.000 claims description 55
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 53
- 239000002245 particle Substances 0.000 claims description 51
- 239000002243 precursor Substances 0.000 claims description 43
- 229910015645 LiMn Inorganic materials 0.000 claims description 32
- 239000011164 primary particle Substances 0.000 claims description 25
- 238000002156 mixing Methods 0.000 claims description 24
- 230000008569 process Effects 0.000 claims description 22
- 239000010936 titanium Substances 0.000 claims description 21
- 229910052751 metal Inorganic materials 0.000 claims description 18
- 239000002994 raw material Substances 0.000 claims description 15
- 229910052719 titanium Inorganic materials 0.000 claims description 13
- 229910052720 vanadium Inorganic materials 0.000 claims description 13
- 239000002184 metal Substances 0.000 claims description 11
- 229910052782 aluminium Inorganic materials 0.000 claims description 9
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 9
- 238000000227 grinding Methods 0.000 claims description 8
- 239000012298 atmosphere Substances 0.000 claims description 7
- 229910052742 iron Inorganic materials 0.000 claims description 7
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims description 6
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 6
- 229910052698 phosphorus Inorganic materials 0.000 claims description 6
- 239000011574 phosphorus Substances 0.000 claims description 6
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 claims description 6
- 239000011572 manganese Substances 0.000 claims description 5
- 239000000203 mixture Substances 0.000 claims description 5
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 4
- 238000004519 manufacturing process Methods 0.000 claims description 4
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims description 3
- 229910052748 manganese Inorganic materials 0.000 claims description 3
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 2
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 claims description 2
- 229910052729 chemical element Inorganic materials 0.000 claims description 2
- 239000010941 cobalt Substances 0.000 claims description 2
- 229910017052 cobalt Inorganic materials 0.000 claims description 2
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 2
- 229910052738 indium Inorganic materials 0.000 claims description 2
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 claims description 2
- 229910052749 magnesium Inorganic materials 0.000 claims description 2
- 239000011777 magnesium Substances 0.000 claims description 2
- 229910052759 nickel Inorganic materials 0.000 claims description 2
- 229910052710 silicon Inorganic materials 0.000 claims description 2
- 239000010703 silicon Substances 0.000 claims description 2
- 229910052726 zirconium Inorganic materials 0.000 claims description 2
- 238000009792 diffusion process Methods 0.000 abstract description 13
- 240000008866 Ziziphus nummularia Species 0.000 abstract 1
- 239000011162 core material Substances 0.000 description 112
- DVATZODUVBMYHN-UHFFFAOYSA-K lithium;iron(2+);manganese(2+);phosphate Chemical compound [Li+].[Mn+2].[Fe+2].[O-]P([O-])([O-])=O DVATZODUVBMYHN-UHFFFAOYSA-K 0.000 description 62
- IUVCFHHAEHNCFT-INIZCTEOSA-N 2-[(1s)-1-[4-amino-3-(3-fluoro-4-propan-2-yloxyphenyl)pyrazolo[3,4-d]pyrimidin-1-yl]ethyl]-6-fluoro-3-(3-fluorophenyl)chromen-4-one Chemical compound C1=C(F)C(OC(C)C)=CC=C1C(C1=C(N)N=CN=C11)=NN1[C@@H](C)C1=C(C=2C=C(F)C=CC=2)C(=O)C2=CC(F)=CC=C2O1 IUVCFHHAEHNCFT-INIZCTEOSA-N 0.000 description 23
- 229910009178 Li1.3Al0.3Ti1.7(PO4)3 Inorganic materials 0.000 description 20
- IIPYXGDZVMZOAP-UHFFFAOYSA-N lithium nitrate Chemical compound [Li+].[O-][N+]([O-])=O IIPYXGDZVMZOAP-UHFFFAOYSA-N 0.000 description 12
- 238000001816 cooling Methods 0.000 description 11
- 238000012360 testing method Methods 0.000 description 10
- LFVGISIMTYGQHF-UHFFFAOYSA-N ammonium dihydrogen phosphate Chemical compound [NH4+].OP(O)([O-])=O LFVGISIMTYGQHF-UHFFFAOYSA-N 0.000 description 9
- 230000000052 comparative effect Effects 0.000 description 9
- 239000012299 nitrogen atmosphere Substances 0.000 description 9
- 238000001704 evaporation Methods 0.000 description 8
- 230000008020 evaporation Effects 0.000 description 8
- 238000010438 heat treatment Methods 0.000 description 8
- 230000005540 biological transmission Effects 0.000 description 7
- 239000003792 electrolyte Substances 0.000 description 7
- 239000004254 Ammonium phosphate Substances 0.000 description 6
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 description 6
- CZMRCDWAGMRECN-UGDNZRGBSA-N Sucrose Chemical compound O[C@H]1[C@H](O)[C@@H](CO)O[C@@]1(CO)O[C@@H]1[C@H](O)[C@@H](O)[C@H](O)[C@@H](CO)O1 CZMRCDWAGMRECN-UGDNZRGBSA-N 0.000 description 6
- 229930006000 Sucrose Natural products 0.000 description 6
- 241001247821 Ziziphus Species 0.000 description 6
- 229910000148 ammonium phosphate Inorganic materials 0.000 description 6
- 235000019289 ammonium phosphates Nutrition 0.000 description 6
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 6
- 239000011258 core-shell material Substances 0.000 description 6
- MNNHAPBLZZVQHP-UHFFFAOYSA-N diammonium hydrogen phosphate Chemical compound [NH4+].[NH4+].OP([O-])([O-])=O MNNHAPBLZZVQHP-UHFFFAOYSA-N 0.000 description 6
- 239000005720 sucrose Substances 0.000 description 6
- 238000000498 ball milling Methods 0.000 description 5
- 239000013078 crystal Substances 0.000 description 5
- 239000007791 liquid phase Substances 0.000 description 5
- 238000011056 performance test Methods 0.000 description 5
- 239000002904 solvent Substances 0.000 description 5
- 229910013553 LiNO Inorganic materials 0.000 description 4
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 4
- 238000002441 X-ray diffraction Methods 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 239000011248 coating agent Substances 0.000 description 4
- 238000000576 coating method Methods 0.000 description 4
- 230000007423 decrease Effects 0.000 description 4
- GNTDGMZSJNCJKK-UHFFFAOYSA-N divanadium pentaoxide Chemical compound O=[V](=O)O[V](=O)=O GNTDGMZSJNCJKK-UHFFFAOYSA-N 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 description 4
- 229910052808 lithium carbonate Inorganic materials 0.000 description 4
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 4
- SNKMVYBWZDHJHE-UHFFFAOYSA-M lithium;dihydrogen phosphate Chemical compound [Li+].OP(O)([O-])=O SNKMVYBWZDHJHE-UHFFFAOYSA-M 0.000 description 4
- 230000005012 migration Effects 0.000 description 4
- 238000013508 migration Methods 0.000 description 4
- 239000007784 solid electrolyte Substances 0.000 description 4
- 238000001694 spray drying Methods 0.000 description 4
- 229910000387 ammonium dihydrogen phosphate Inorganic materials 0.000 description 3
- 239000010405 anode material Substances 0.000 description 3
- 238000004090 dissolution Methods 0.000 description 3
- 239000011888 foil Substances 0.000 description 3
- 230000006872 improvement Effects 0.000 description 3
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 3
- MVFCKEFYUDZOCX-UHFFFAOYSA-N iron(2+);dinitrate Chemical compound [Fe+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O MVFCKEFYUDZOCX-UHFFFAOYSA-N 0.000 description 3
- MIVBAHRSNUNMPP-UHFFFAOYSA-N manganese(2+);dinitrate Chemical compound [Mn+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O MIVBAHRSNUNMPP-UHFFFAOYSA-N 0.000 description 3
- 235000019837 monoammonium phosphate Nutrition 0.000 description 3
- 239000006012 monoammonium phosphate Substances 0.000 description 3
- 239000002033 PVDF binder Substances 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- YWJVFBOUPMWANA-UHFFFAOYSA-H [Li+].[V+5].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O Chemical compound [Li+].[V+5].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O YWJVFBOUPMWANA-UHFFFAOYSA-H 0.000 description 2
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 2
- 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 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- YHWCPXVTRSHPNY-UHFFFAOYSA-N butan-1-olate;titanium(4+) Chemical compound [Ti+4].CCCC[O-].CCCC[O-].CCCC[O-].CCCC[O-] YHWCPXVTRSHPNY-UHFFFAOYSA-N 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 239000011267 electrode slurry Substances 0.000 description 2
- 238000004146 energy storage Methods 0.000 description 2
- AMWRITDGCCNYAT-UHFFFAOYSA-L hydroxy(oxo)manganese;manganese Chemical compound [Mn].O[Mn]=O.O[Mn]=O AMWRITDGCCNYAT-UHFFFAOYSA-L 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- VCJMYUPGQJHHFU-UHFFFAOYSA-N iron(3+);trinitrate Chemical compound [Fe+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O VCJMYUPGQJHHFU-UHFFFAOYSA-N 0.000 description 2
- XIXADJRWDQXREU-UHFFFAOYSA-M lithium acetate Chemical compound [Li+].CC([O-])=O XIXADJRWDQXREU-UHFFFAOYSA-M 0.000 description 2
- 229940099596 manganese sulfate Drugs 0.000 description 2
- 235000007079 manganese sulphate Nutrition 0.000 description 2
- 239000011702 manganese sulphate Substances 0.000 description 2
- SQQMAOCOWKFBNP-UHFFFAOYSA-L manganese(II) sulfate Chemical compound [Mn+2].[O-]S([O-])(=O)=O SQQMAOCOWKFBNP-UHFFFAOYSA-L 0.000 description 2
- -1 nickel-cobalt-aluminum Chemical compound 0.000 description 2
- 238000005498 polishing Methods 0.000 description 2
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 2
- 238000010298 pulverizing process Methods 0.000 description 2
- 238000001878 scanning electron micrograph Methods 0.000 description 2
- 238000007086 side reaction Methods 0.000 description 2
- 239000013589 supplement Substances 0.000 description 2
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 2
- BNGXYYYYKUGPPF-UHFFFAOYSA-M (3-methylphenyl)methyl-triphenylphosphanium;chloride Chemical compound [Cl-].CC1=CC=CC(C[P+](C=2C=CC=CC=2)(C=2C=CC=CC=2)C=2C=CC=CC=2)=C1 BNGXYYYYKUGPPF-UHFFFAOYSA-M 0.000 description 1
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- WQZGKKKJIJFFOK-GASJEMHNSA-N Glucose Natural products OC[C@H]1OC(O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-GASJEMHNSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910010710 LiFePO Inorganic materials 0.000 description 1
- 229910010707 LiFePO 4 Inorganic materials 0.000 description 1
- 229910013870 LiPF 6 Inorganic materials 0.000 description 1
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 239000002202 Polyethylene glycol Substances 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 229910010413 TiO 2 Inorganic materials 0.000 description 1
- KFDQGLPGKXUTMZ-UHFFFAOYSA-N [Mn].[Co].[Ni] Chemical compound [Mn].[Co].[Ni] KFDQGLPGKXUTMZ-UHFFFAOYSA-N 0.000 description 1
- AZFUOHYXCLYSQJ-UHFFFAOYSA-N [V+5].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O Chemical compound [V+5].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O AZFUOHYXCLYSQJ-UHFFFAOYSA-N 0.000 description 1
- 239000006230 acetylene black Substances 0.000 description 1
- 239000004480 active ingredient Substances 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 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
- 238000004458 analytical method Methods 0.000 description 1
- UNTBPXHCXVWYOI-UHFFFAOYSA-O azanium;oxido(dioxo)vanadium Chemical compound [NH4+].[O-][V](=O)=O UNTBPXHCXVWYOI-UHFFFAOYSA-O 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- WQZGKKKJIJFFOK-VFUOTHLCSA-N beta-D-glucose Chemical compound OC[C@H]1O[C@@H](O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-VFUOTHLCSA-N 0.000 description 1
- 229910002056 binary alloy Inorganic materials 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 239000006229 carbon black Substances 0.000 description 1
- 238000003763 carbonization Methods 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 238000012512 characterization method Methods 0.000 description 1
- 238000000975 co-precipitation Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000006258 conductive agent Substances 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- QHGJSLXSVXVKHZ-UHFFFAOYSA-N dilithium;dioxido(dioxo)manganese Chemical compound [Li+].[Li+].[O-][Mn]([O-])(=O)=O QHGJSLXSVXVKHZ-UHFFFAOYSA-N 0.000 description 1
- 235000003891 ferrous sulphate Nutrition 0.000 description 1
- 239000011790 ferrous sulphate Substances 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 239000008103 glucose Substances 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- CPSYWNLKRDURMG-UHFFFAOYSA-L hydron;manganese(2+);phosphate Chemical compound [Mn+2].OP([O-])([O-])=O CPSYWNLKRDURMG-UHFFFAOYSA-L 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 1
- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 1
- 229910000664 lithium aluminum titanium phosphates (LATP) Inorganic materials 0.000 description 1
- ZAUUZASCMSWKGX-UHFFFAOYSA-N manganese nickel Chemical compound [Mn].[Ni] ZAUUZASCMSWKGX-UHFFFAOYSA-N 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000007709 nanocrystallization Methods 0.000 description 1
- 239000002105 nanoparticle Substances 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 239000010450 olivine Substances 0.000 description 1
- 229910052609 olivine Inorganic materials 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- NDLPOXTZKUMGOV-UHFFFAOYSA-N oxo(oxoferriooxy)iron hydrate Chemical compound O.O=[Fe]O[Fe]=O NDLPOXTZKUMGOV-UHFFFAOYSA-N 0.000 description 1
- 239000012188 paraffin wax Substances 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 235000011007 phosphoric acid Nutrition 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 229920001223 polyethylene glycol Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 238000004080 punching Methods 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 238000010532 solid phase synthesis reaction Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 238000001291 vacuum drying Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/362—Composites
- H01M4/366—Composites as layered products
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/04—Processes of manufacture in general
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/04—Processes of manufacture in general
- H01M4/0471—Processes of manufacture in general involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/136—Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
- H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/624—Electric conductive fillers
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/624—Electric conductive fillers
- H01M4/625—Carbon or graphite
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
- H01M2004/028—Positive electrodes
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Abstract
The application relates to the technical field of lithium ion battery materials, and provides a lithium-containing phosphate composite material which comprises an inner core and an outer shell layer which are sequentially combined from inside to outside along the radial direction, wherein the inner core comprises a lithium-containing phosphate active material and lithium ion conductor materials distributed in the lithium-containing phosphate active material, and the outer shell layer comprises a carbon layer. The lithium-containing phosphate composite material provided by the application comprises the inner core with the jujube cake structure, the existence of the lithium ion conductor material enriches the diffusion path of lithium ions, and improves the content of lithium ions and the ionic conductivity, so that the capacity of the lithium-containing phosphate active material is exerted, the electronic conductivity in the lithium-containing phosphate active material can be effectively improved, the internal resistance and the impedance of a lithium ion battery are reduced, and the low-temperature performance and the multiplying power performance of the lithium-containing phosphate positive electrode material are effectively improved.
Description
Technical Field
The application belongs to the technical field of lithium ion battery materials, and particularly relates to a lithium-containing phosphate composite material, and a preparation method and application thereof.
Background
The lithium ion battery has the advantages of high working voltage, low self-discharge, good safety and the like, and is widely applied to the energy storage field, power batteries and portable electronic equipment as an energy storage device. The positive electrode material of the lithium ion battery mainly comprises lithium cobaltate, lithium manganate, a nickel-manganese binary system, a nickel-cobalt-manganese ternary system, a nickel-cobalt-aluminum ternary system, lithium iron phosphate, lithium manganese iron phosphate and the like. Wherein, the lithium-containing phosphate anode materials such as lithium iron phosphate, lithium manganese iron phosphate and the like belong to a lithium ion battery anode material with an olivine structure, and have the characteristic of reversibly removing and inserting lithium, but have low intrinsic conductivity, so that Li is formed by + In which the diffusion rate is low and the electron conductivity is low. At present, the lithium-containing phosphate positive electrode material is modified mainly by doping, particle nanocrystallization and the like so as to improve the conductivity of the lithium-containing phosphate positive electrode material. The metal element doping can improve the migration rate of lithium ions to a certain extent, but the problems of rate performance attenuation and poor performance under the low-temperature condition still exist, and the exertion of the electrochemical performance of the lithium-containing phosphate anode material is limited.
Disclosure of Invention
The application aims to provide a lithium-containing phosphate composite material and a preparation method thereof, and aims to solve the problem that the rate performance and low-temperature performance of a lithium-containing phosphate positive electrode material are required to be further improved.
Another object of the present application is to provide a positive electrode and a secondary battery including the positive electrode, which aims to solve the technical problem of poor rate performance of the existing secondary battery.
In order to achieve the purposes of the application, the technical scheme adopted by the application is as follows:
in a first aspect, the present application provides a lithium-containing phosphate composite material, comprising an inner core and an outer shell, which are sequentially combined from inside to outside along a radial direction, wherein the material of the inner core comprises a lithium-containing phosphate active material and a lithium ion conductor material distributed in the lithium-containing phosphate active material, and the chemical formula of the lithium ion conductor material is Li a M b (PO 4 ) 3 M comprises at least one of Ti, al and V, a is more than or equal to 1 and less than or equal to 3, b is more than or equal to 0.1 and less than or equal to 2, and the shell layer comprises a carbon layer.
The lithium-containing phosphate composite material provided in the first aspect of the application comprises a lithium-containing phosphate active material and a lithium ion conductor material (Li a M b (PO 4 ) 3 ) The inner core with the jujube cake structure is formed, the existence of the lithium ion conductor material enriches the diffusion path of lithium ions, and improves the content and ionic conductivity of lithium ions, so that the capacity of the lithium-containing phosphate active material is brought into play, the electronic conductivity in the lithium-containing phosphate active material can be effectively improved, the internal resistance and impedance of a lithium ion battery are reduced, and the low-temperature performance and the rate performance of the lithium-containing phosphate positive electrode material are effectively improved; meanwhile, the lithium ion conductor material can also supplement lithium ions consumed by forming an SEI film (Solid Electrolyte Interface, solid electrolyte interface film), so that the first coulomb efficiency of the material is improved; the outer surface of the inner core is also coated with a carbon layer, the carbon layer not only can improve the conductivity of the lithium-containing phosphate composite material, but also can effectively isolate the lithium-containing phosphate active material from being contacted with electrolyte and inhibit the dissolution of metal elements, so that the occurrence of side reaction is reduced, the addition improvement effect is achieved on improving the conductivity and structural stability of the lithium-containing phosphate composite material, and the lithium-containing phosphate composite material is further endowed with higher low-temperature performance, rate discharge performance and cycle performance.
In a second aspect, the present application provides a method of preparing a lithium-containing phosphate composite material, comprising the steps of:
step S10, providing a precursor of a lithium-containing phosphate active material, a lithium ion conductor material and a carbon source;
step S20, mixing a precursor of the lithium-containing phosphate active material with a lithium ion conductor material, and then performing first sintering treatment to enable the lithium-containing phosphate active material to be inlaid with the lithium ion conductor material, so as to obtain a core;
and step S30, mixing the inner core with a carbon source, and performing second sintering treatment to coat the carbon layer on the surface of the inner core, thereby obtaining the lithium-containing phosphate composite material.
According to the preparation method of the lithium-containing phosphate composite material provided by the second aspect of the application, after the lithium-containing phosphate active material precursor and the lithium ion conductor material are mixed, the lithium-containing phosphate active material is subjected to sintering treatment, and the lithium-containing phosphate active material is inlaid with the lithium-coated conductor material to form the inner core of the jujube cake structure; and adding a carbon source for sintering treatment, and coating a carbon layer on the surface of the inner core, thereby forming the lithium-containing phosphate composite material with the core-shell structure. The preparation method of the lithium-containing phosphate composite material can effectively prepare the lithium-containing phosphate composite material with stable structure and electrochemical performance, the preparation process is simple, the preparation method is suitable for industrial mass production and application, and the lithium-containing phosphate composite material with the core-shell structure can improve the conductivity of the core material and the diffusion speed of lithium ions, so that the positive electrode composite material has higher electrochemical performances such as low-temperature performance, rate discharge performance, cycle performance, safety, stability and the like.
In a third aspect, the present application provides a positive electrode comprising a current collector and a positive electrode active layer bonded to the current collector, the positive electrode active material contained in the positive electrode active layer comprising the lithium-containing phosphate composite of the present application or the lithium-containing phosphate composite produced by the method of producing the lithium-containing phosphate composite of the present application.
The lithium-containing phosphate composite material with the core-shell structure has the comprehensive properties of high low-temperature performance, high rate discharge performance, high cycle performance, high safety, high stability and the like, so that the electrochemical properties of the positive electrode such as the rate discharge performance, the cycle stability, the low-temperature performance and the like are improved.
In a fourth aspect, the application provides a secondary battery comprising a positive plate, a negative plate, a diaphragm and electrolyte, wherein the positive plate is the positive electrode of the application.
The secondary battery provided in the fourth aspect of the present application has good low-temperature performance, good rate discharge performance and good cycle performance because of the inclusion of the positive electrode of the present application.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments or the description of the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic structural view of a lithium-containing phosphate composite material provided in an embodiment of the present application;
FIG. 2 is a scanning electron micrograph of a lithium-containing phosphate composite material provided in example 1 of the present application;
fig. 3 is an X-ray diffraction analysis chart of the lithium-containing phosphate composite material provided in example 1 of the present application.
Detailed Description
In order to make the technical problems, technical schemes and beneficial effects to be solved more clear, the application is further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.
In the present application, the term "and/or" describes an association relationship of an association object, which means that three relationships may exist, for example, a and/or B may mean: a alone, a and B together, and B alone. Wherein A, B may be singular or plural. The character "/" generally indicates that the context-dependent object is an "or" relationship.
In the present application, "at least one" means one or more, and "a plurality" means two or more. "at least one of" or the like means any combination of these items, including any combination of single item(s) or plural items(s). For example, "at least one (individual) of a, b, or c," or "at least one (individual) of a, b, and c," may each represent: a, b, c, a-b (i.e., a and b), a-c, b-c, or a-b-c, wherein a, b, c may be single or multiple, respectively.
It should be understood that, in various embodiments of the present application, the sequence number of each process described above does not mean that the execution sequence of some or all of the steps may be executed in parallel or executed sequentially, and the execution sequence of each process should be determined by its functions and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.
The terminology used in the embodiments of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in this application and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
The weights of the relevant components mentioned in the description of the embodiments of the present application may refer not only to the specific contents of the components, but also to the proportional relationship between the weights of the components, so long as the contents of the relevant components in the description of the embodiments of the present application are scaled up or down within the scope of the disclosure of the embodiments of the present application. Specifically, the mass described in the specification of the embodiment of the application can be mass units known in the chemical industry field such as mu g, mg, g, kg.
The terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated for distinguishing between objects such as substances from each other. For example, a first XX may also be referred to as a second XX, and similarly, a second XX may also be referred to as a first XX, without departing from the scope of embodiments of the application. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature.
According to a first aspect of the embodiment of the application, a lithium-containing phosphate composite material is provided, which comprises an inner core and an outer shell which are sequentially combined from inside to outside along a radial direction, wherein the material of the inner core comprises a lithium-containing phosphate active material and lithium ion conductor materials distributed in the lithium-containing phosphate active material, and the chemical formula of the lithium ion conductor materials is Li a M b (PO 4 ) 3 M comprises at least one of Ti, al and V, a is more than or equal to 1 and less than or equal to 3, b is more than or equal to 0.1 and less than or equal to 2, and the shell layer comprises a carbon layer.
The lithium-containing phosphate composite material provided by the first aspect of the embodiment of the application comprises a lithium-containing phosphate active material and a lithium ion conductor material (Li a M b (PO 4 ) 3 ) The inner core with the jujube cake structure is formed, the existence of the lithium ion conductor material enriches the diffusion path of lithium ions, and improves the content and ionic conductivity of lithium ions, so that the capacity of the lithium-containing phosphate active material is brought into play, the electronic conductivity in the lithium-containing phosphate active material can be effectively improved, the migration rate of lithium ions is improved, the internal resistance and the impedance of a lithium ion battery are reduced, and the low-temperature performance and the rate performance of the lithium-containing phosphate positive electrode material are effectively improved; meanwhile, the lithium ion conductor material can also supplement lithium ions consumed by forming an SEI film (Solid Electrolyte Interface, solid electrolyte interface film), so that the first coulomb efficiency of the material is improved; the outer surface of the inner core is also coated with a carbon layer, the carbon layer not only can improve the conductivity of the lithium-containing phosphate composite material, but also can effectively isolate the lithium-containing phosphate active material from being contacted with electrolyte and inhibit the dissolution of metal elements, so that the occurrence of side reaction is reduced, the addition improvement effect is achieved on improving the conductivity and structural stability of the lithium-containing phosphate composite material, and the lithium-containing phosphate composite material is further endowed with higher low-temperature performance, rate discharge performance and cycle performance.
As shown in fig. 1, the lithium-containing phosphate composite material provided by the embodiment of the application comprises a lithium-containing phosphate active material, lithium ion conductor materials uniformly distributed in the lithium-containing phosphate active material, and a carbon layer coating the lithium-containing phosphate active material.
In some embodiments, the lithium-containing phosphate active material has the chemical formula LiMn x Fe 1-x-y N y PO 4 Wherein N comprises at least one of Ti, al, V, mg, zr, co, ni, si, in, x is more than or equal to 0 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 0.2, and 0 is more than or equal to 1-x-y is more than or equal to 1. The lithium-containing phosphate active material contains the doping element N, and the element forms iron site doping, so that the voltage platform of the active material is improved, the energy density of the active material is improved obviously, and the lithium-containing phosphate composite material has the comprehensive properties of higher energy density, high cycle stability, excellent multiplying power performance, low temperature performance and the like.
In some embodiments, the lithium-containing phosphate active material is doped with lithium ion conductor material Li a M b (PO 4 ) 3 The metal element M in the lithium-containing phosphate active material is present in the form of a single atom. In the embodiment of the application, part of metal elements M contained in the lithium ion conductor material are in a chemical doping mode, and part of iron atoms in the lithium-containing phosphate active material are replaced by metal elements in a single atom mode to form the metal element atom doped lithium-containing phosphate active material. The metal element M comprises at least one of Ti, al and V, wherein the ionic radius of vanadium and aluminum is close to that of iron, but the valence state is higher than that of iron, and the high valence doping ensures that Fe 2+ /Fe 3+ Coexistence, the intrinsic conductivity of the material is improved; the titanium can stabilize the lattice structure, reduce the cell parameters and reduce the polarization degree of the active material, thereby improving the cycle performance and the multiplying power performance of the composite material. The doping of the metal element can widen the lithium ion transmission path, and the doping of the high-valence metal ion can generate more surplus electrons, so that the conductivity and gram capacity of the positive electrode composite material are effectively improved. In addition, the doping of the metal element can also increase the binding force of the lithium ion conductor material to the lithium-containing phosphate active material, so that the structural stability of the composite material is improved.
In the technical scheme of the embodiment of the application, the lithium ion conductor material in the inner core has two existing forms: in one aspect, a portion of the lithium ion conductor material is embedded in the lithium-containing phosphate active material in the form of particles to form a core of jujube cake structure; on the other hand, a part of the metal element M in the lithium ion conductor material is doped into the lattice of the lithium-containing phosphate to form an element doping. The existence form of the composite increases the binding force between the lithium-containing phosphate active material and the lithium ion conductor material, simultaneously enriches the lithium ion diffusion path of the lithium-containing phosphate active material, plays an additive improving role in improving the conductivity and structural stability of the lithium-containing phosphate composite material, and further endows the lithium-containing phosphate composite material with higher low-temperature performance, rate discharge performance and cycle performance.
In some embodiments, the particle size of the lithium ion conductor material in the core is from 5nm to 20nm. Specifically, the particle size of the lithium ion conductor material may be 5nm, 8nm, 10nm, 12nm, 15nm, 18nm, 20nm or within a range composed of any of the above values.
In some embodiments, an intermediate layer is also provided between the inner core and the outer shell, the intermediate layer comprising a lithium ion conductor material. The lithium ion conductor material used as the intermediate layer can further improve the transmission rate of lithium ions, thereby improving the conductivity of the lithium-containing phosphate active material, improving the electrochemical performance of the material, reducing the internal resistance and the impedance of a lithium ion battery and improving the low-temperature performance and the multiplying power charge-discharge performance of the material.
In some embodiments, the thickness of the intermediate layer is from 0.5nm to 3nm. Specifically, the thickness of the intermediate layer includes, but is not limited to, 0.5nm, 1nm, 1.5nm, 2nm, 2.5nm, 3nm.
In some embodiments, the mass of lithium ion conductor material in the core and the intermediate layer comprises 0.5wt% to 3wt% of the total mass of the lithium-containing phosphate composite. The mass ratio in the embodiment of the application refers to the total mass ratio of the lithium ion conductor material included in the core and the lithium ion conductor material included in the intermediate layer. If the mass ratio of the lithium ion conductor material is too low, the content of the embedded lithium ion conductor material in the lithium-containing phosphate active material and the content of the metal element doped in the lithium-containing phosphate active material are influenced, so that the conductivity of the lithium-containing phosphate active material is limited; if the mass ratio of the lithium ion conductor material is too high, the lithium ion conductor material contained in the lithium-containing phosphate may be agglomerated, and the formed intermediate layer may have too high thickness and uneven thickness, thereby affecting the diffusion speed of lithium ions and being unfavorable for the performance of the multiplying power of the composite material. Specifically, the mass ratio of the lithium ion conductor material may be 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt% or within a range composed of any of the above values.
In some embodiments, the mass ratio of lithium ion conductor material in the core and the intermediate layer is 6:4 to 7:3. If the ratio of the lithium ion conductor material in the core is too high, it indicates that an intermediate layer may not be formed between the core and the shell, or the thickness of the intermediate layer is too low, thereby affecting the transmission rate of lithium ions in the lithium ion active material. If the duty ratio of the lithium ion conductor material in the core is too low, on one hand, the improvement of the electrochemical performance of the lithium-containing phosphate active material cannot be realized, and on the other hand, the fact that the thickness of the intermediate layer between the core and the shell is too high is indicated, so that the transmission path of lithium ions in the core is too long, and the transmission rate of the lithium ions is affected. Specifically, the mass ratio of lithium ion conductor material in the core and the intermediate layer may include, but is not limited to, 6:3, 6:4, 7:3, 7:4.
In some embodiments, the carbon layer comprises 0.8wt% to 3wt% of the total mass of the lithium-containing phosphate composite. In the range of the mass ratio of the carbon layer provided by the embodiment of the application, the conductive performance of the lithium-containing phosphate composite material is improved, the diffusion rate of lithium ions is obviously increased, and the lithium-containing phosphate active material and the lithium ion conductor material can be completely coated, so that the lithium-containing phosphate active material is prevented from being contacted with electrolyte, the dissolution of metal elements is avoided, the growth of composite material particles can be inhibited, the primary particle size of the composite material is in a nano level, and the development of the electrochemical performance of the lithium-containing phosphate composite material is facilitated. Specifically, the mass ratio of the carbon layer may be 0.8wt%, 1wt%, 1.3wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt% or within a range composed of any of the above values.
In some embodiments, the thickness of the outer shell layer is from 1nm to 3nm. If the thickness of the outer shell layer is too low, the lithium-containing phosphate active material and the lithium ion conductor material cannot be well coated, so that the cycle stability and the multiplying power performance of the composite material are poor; if the thickness of the outer shell layer is too high, the migration path of lithium ions is too high, and the transmission of lithium ions is also inevitably blocked, so that the ion conductivity and the electron conductivity of the composite material are affected. In the thickness range of the carbon layer provided by the embodiment of the application, the lithium-containing phosphate active material and the lithium ion conductor material are completely coated, and lithium ions are in a proper migration path range, so that the composite material has higher ion conductivity and electron conductivity. In particular, the thickness of the outer shell layer may be 1nm, 2nm, 2.5nm, 3nm, or within a range comprised of any of the above values.
In some embodiments, the primary particle size of the lithium-containing phosphate composite is from 100nm to 200nm. It is understood that primary particle size refers to the particle size of individual particles of the lithium-containing phosphate composite under microscopic test conditions, i.e., individual microscopic particle sizes. The primary particle size of the lithium-containing phosphate composite material is nano-scale, the particle size is small, the activity specific surface area is large, and the diffusion path of lithium ions can be effectively shortened, so that the diffusion rate of the lithium ions can be improved, and the low-temperature performance and the multiplying power performance of the lithium-containing phosphate composite material can be better exerted. In particular, the primary particle size of the lithium-containing phosphate composite may include, but is not limited to, 100nm to 120nm, or 110nm to 130nm, or 130nm to 150nm, or 140nm to 160nm, or 180nm to 200nm.
A second aspect of the embodiments of the present application provides a method for preparing a lithium-containing phosphate composite material, comprising the steps of:
step S10, providing a precursor of a lithium-containing phosphate active material, a lithium ion conductor material and a carbon source;
step S20, mixing a precursor of the lithium-containing phosphate active material with a lithium ion conductor material, and then performing first sintering treatment to enable the lithium-containing phosphate active material to be inlaid with the lithium ion conductor material, so as to obtain a core;
and step S30, mixing the inner core with a carbon source, and performing second sintering treatment to coat the carbon layer on the surface of the inner core, thereby obtaining the lithium-containing phosphate composite material.
According to the preparation method of the lithium-containing phosphate composite material provided by the second aspect of the embodiment of the application, the lithium-containing phosphate active material precursor and the lithium ion conductor material are mixed and then sintered, and the lithium ion conductor material is inlaid in the lithium-containing phosphate active material to form the inner core of the jujube cake structure; and adding a carbon source for sintering treatment, and coating a carbon layer on the surface of the inner core, thereby forming the lithium-containing phosphate composite material with the core-shell structure. The preparation method of the lithium-containing phosphate composite material can effectively prepare the lithium-containing phosphate composite material with stable structure and electrochemical performance, the preparation process is simple, the preparation method is suitable for industrial mass production and application, and the lithium-containing phosphate composite material with the core-shell structure can improve the conductivity of the core material and the diffusion speed of lithium ions, so that the positive electrode composite material has higher electrochemical performances such as low-temperature performance, rate discharge performance, cycle performance, safety, stability and the like.
In some embodiments, in step S10, the lithium-containing phosphate active material precursor is subjected to a sintering process to produce a lithium-containing phosphate active material, constituting the lithium-containing phosphate active material in the above core; the lithium ion conductor material is sintered and can be inlaid in the lithium-containing phosphate active material to form an inner core in the lithium-containing phosphate composite material together with the lithium-containing phosphate active material; the carbon source may be sintered to coat the surface of the core and form the outer shell layer in the lithium-containing phosphate composite material described above.
In some embodiments, in step S10, the carbon source comprises at least one of glucose, sucrose, polyvinylidene fluoride, carbon black, polyethylene glycol, and paraffin. The embodiment of the application can flexibly select the carbon source required by the lithium-containing phosphate composite material according to the requirement.
In some embodiments, in step S10, the lithium-containing phosphate active material precursor has the chemical formula LiMn x Fe 1-x-y N y PO 4 X is more than or equal to 0 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 0.2,0 is more than or equal to 1-x-y is less than 1, and the preparation method of the precursor of the lithium-containing phosphate active material comprises the following steps:
according to the chemical formula LiMn x Fe 1-x-y N y PO 4 The stoichiometric ratio of the chemical elements is shown, a first raw material component comprising a first lithium source, a first phosphorus source, an iron source, a manganese source and an N source is obtained, the first raw material component is mixed and reacted to obtain a lithium-containing phosphate active material precursor, wherein the N source comprises at least one of a titanium source, an aluminum source, a vanadium source, a magnesium source, a zirconium source, a cobalt source, a nickel source, a silicon source and an indium source. The lithium-containing phosphate active material precursor may be prepared using methods well known in the art, such as liquid phase methods, solid phase methods, co-precipitation methods, and the like.
Specifically, the first lithium source is selected from at least one of lithium carbonate, lithium dihydrogen phosphate, lithium hydroxide, lithium acetate, and lithium nitrate.
Specifically, the first phosphorus source comprises at least one of ammonium phosphate, lithium dihydrogen phosphate, and phosphoric acid.
Specifically, the iron source includes at least one of ferric nitrate, ferric oxide, and ferrous sulfate.
Specifically, the manganese source includes at least one of manganese oxide, manganese nitrate, manganese sulfate, and manganese phosphate.
Specifically, the N source is a raw material containing a doping element, and the doping element includes Ti, al, V, mg, zr, co, ni, si, in.
In some embodiments, in step S10, the method for preparing a lithium ion conductor material includes the steps of:
according to the chemical general formula Li a M b (PO 4 ) 3 The stoichiometric ratio of each element in the lithium ion conductor material is obtained, a second raw material component comprising a second lithium source, a second phosphorus source and an M source is obtained, and the second raw material component is subjected to fourth sintering treatment to obtain the lithium ion conductor material, wherein the M source comprises at least one of an aluminum source, a titanium source and a vanadium source, a is more than or equal to 1 and less than or equal to 3, and b is more than or equal to 0.1 and less than or equal to 2.
According to the embodiment of the application, the formation of crystal nuclei of the lithium ion conductor material can be promoted in the sintering treatment process after the synthesis raw materials of the lithium ion conductor material are mixed.
In some embodiments, the fourth sintering process may further comprise ball milling the second feedstock component at a rotational speed of 300rpm to 500rpm for 1 hour to 4 hours. According to the embodiment of the application, the raw material components comprising the lithium ion conductor material are subjected to grinding treatment, so that the particle size of each component in the synthetic raw material can be reduced while the components are uniformly mixed. Specifically, the rotation speed of the second polishing treatment may be 300rpm, 350rpm, 400rpm, 450rpm, 500rpm or within a range consisting of any of the above values. Specifically, the time of the second polishing treatment may be 1h, 2h, 3h, 4h or within a range consisting of any of the above values.
In some embodiments, the conditions of the fourth sintering process include: sintering for 1-3 h at 100-300 ℃, then sintering for 4-10 h at 700-1000 ℃, and then sintering for 4-10 h at 800-1000 ℃. In the fourth sintering treatment process provided by the embodiment of the application, the purpose of sintering at the temperature of 100-300 ℃ in the first stage is mainly to remove ash and water in the synthetic raw materials; the second stage is to raise the temperature from the first stage to 700-1000 deg.c for the purpose of crystallizing the lithium ion conductor material to form crystal nucleus and limiting the crystal nucleus growth speed and crystal grain size; the purpose of the third stage sintering is to further promote crystallization of the lithium ion conductor material to form a final product with a regular morphology. Specifically, the temperature rising rate of the second stage and the third stage is 3-5 ℃/min.
Specifically, in the fourth sintering process, before the third stage sintering, the method further includes: and (5) particle size refinement treatment. Wherein the particle size refining treatment includes at least one of grinding and air stream pulverization. In this way, the sintered material can be ensured to have proper size, and the material is prevented from being discarded as waste after being screened later.
In some embodiments, the particle size of the lithium ion conductor material in the core is from 5nm to 20nm. In the particle size range of the lithium ion conductor material provided by the embodiment of the application, the subsequent uniform mixing with the precursor of the lithium-containing phosphate active material is facilitated, and the lithium-containing phosphate composite material with the nano-scale particle size is formed. In particular, the particle size of the lithium ion conductor material may include, but is not limited to, 5nm, 8nm, 10nm, 12nm, 15nm, 18nm, 20nm.
Specifically, the second phosphorus source includes at least one of ammonium phosphate, monoammonium phosphate, phosphoric acid, and lithium dihydrogen phosphate.
Specifically, the second lithium source is selected from at least one of lithium carbonate, lithium dihydrogen phosphate, lithium hydroxide, lithium acetate, and lithium nitrate.
Specifically, the titanium source includes at least one of titanium oxide and tetrabutyl titanate.
Specifically, the aluminum source includes at least one of aluminum oxide, aluminum hydroxide, and aluminum nitrate.
Specifically, the vanadium source includes at least one of ammonium metavanadate, vanadium nitrate, and vanadium pentoxide.
In some embodiments, in step S20, the mass ratio of the lithium-containing phosphate active material precursor to the lithium ion conductor material is 100:0.30 to 1.86. In the addition amount of the lithium ion conductor material provided by the embodiment of the application, the lithium ion active material can be inlaid in the lithium-containing phosphate active material, and at least part of metal elements can enter the lithium-containing phosphate active material to form iron site doping. Specifically, the mass ratio of the lithium-containing phosphate active material precursor to the lithium ion conductor material may be 100:0.30 to 0.50, or 100:0.50 to 1, or 100:1 to 1.5, or 100:1.5 to 1.86.
In some embodiments, in step S20, the first sintering process may further include mixing the lithium-containing phosphate active material precursor with the lithium ion conductor material and grinding to a particle size of 0.5 μm to 0.7 μm. The lithium ion conductor material and the lithium-containing phosphate active material precursor are mixed, and grinding treatment is carried out to refine the particle size of the particles and improve the uniformity of the particle size of the particles.
In some embodiments, in step S20, the first sintering process is preceded by spray drying at a temperature of 100 ℃ to 200 ℃ after mixing the lithium-containing phosphate active material precursor with the lithium ion conductor material. According to the embodiment of the application, the lithium ion conductor material and the precursor of the lithium-containing phosphate active material can be uniformly mixed through spray drying. Specifically, the temperature of the drying treatment may be 100℃to 120℃or 120℃to 140℃or 130℃to 150℃or 150℃to 170℃or 180℃to 200 ℃.
In some embodiments, in step S20, after mixing the lithium-containing phosphate active material precursor with the lithium ion conductor material, the mixture is first ground to a particle size of 0.5 μm to 0.7 μm, then dried, and then subjected to a first sintering process.
In some embodiments, in step S20, the conditions of the first sintering process include: sintering for 6-12 h in an inert atmosphere with the temperature of 500-700 ℃. In the first sintering treatment process, the lithium ion conductor material can be inlaid into the lithium-containing phosphate active material, and part of metal elements contained in the lithium ion conductor material can be doped into the lithium-containing phosphate active material, so that the conductivity of the lithium-containing phosphate positive electrode material is effectively improved. Specifically, the temperature of the first sintering treatment may be 500 ℃, 550 ℃, 600 ℃, 650 ℃, 700 ℃ or within a range consisting of any of the above values. The time of the first sintering process includes, but is not limited to, 6h, 7h, 8h, 9h, 10h, or 12h.
In some embodiments, in step S30, before mixing the core with the carbon source, further comprises:
and mixing the inner core with the raw materials of the lithium ion conductor material, grinding, and then performing third sintering treatment to coat the surface of the inner core with an intermediate layer. In the third sintering process, the surface of the inner core of the jujube cake structure can be coated with a lithium ion conductor material, so that the transmission path of lithium ions is widened.
In some embodiments, the conditions of the third sintering process include: sintering for 6-12 h in the inert atmosphere with the temperature of 700-1000 ℃.
In some embodiments, in step S30, the conditions of the second sintering process include: sintering for 6-12 h in an inert atmosphere with the temperature of 600-900 ℃. During the second sintering process, the carbon source can be converted to gaseous hydrocarbons, which can deposit on the surface of the core to form a carbon layer. The sintering time should be sufficient to ensure sufficient carbonization of the carbon source. Specifically, the temperature of the second sintering treatment may be 600 ℃, 700 ℃, 800 ℃, 900 ℃ or within a range consisting of any of the above values.
In some embodiments, in step S30, the mass ratio of carbon source to intermediate material is 1 to 5:100. specifically, the mass ratio of carbon source to intermediate material may include, but is not limited to, 1: 100. 2: 100. 3: 100. 4: 100. 5:100.
A third aspect of the embodiment of the present application provides a positive electrode, including a current collector and a positive electrode active layer bonded to the current collector, where the positive electrode active material included in the positive electrode active layer includes the lithium-containing phosphate composite material of the present application or the lithium-containing phosphate composite material prepared by the preparation method of the lithium-containing phosphate composite material of the present application.
The lithium-containing phosphate composite material with the core-shell structure has high comprehensive properties such as low-temperature performance, rate discharge performance, cycle performance, safety, stability and the like, so that the electrochemical properties such as rate discharge performance, cycle stability, low-temperature performance and the like of the positive electrode are improved.
A fourth aspect of the embodiment of the present application provides a secondary battery, including a positive electrode sheet, a negative electrode sheet, a separator, and an electrolyte, the positive electrode sheet including the positive electrode of the present application.
The secondary battery provided by the fourth aspect of the embodiment of the application has good low-temperature performance, good rate discharge performance and good cycle performance due to the inclusion of the positive electrode of the application.
The following description is made with reference to specific embodiments.
Example A1
The embodiment provides a lithium-containing phosphate composite material, which comprises an inner core and an outer shell which are sequentially combined from inside to outside along the radial direction, wherein the material of the inner core comprises a lithium iron manganese phosphate active material and a lithium ion conductor material embedded in the lithium iron manganese phosphate active material, and the chemical formula of the lithium iron manganese phosphate active material is LiMn 0.05 Fe 0.95 PO 4 The chemical formula of the lithium ion conductor material is Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 The outer shell layer includes a carbon layer. The lithium ion conductor material accounts for 0.5 weight percent of the total mass of the lithium-containing phosphate composite material, and the carbon layer accounts for 1.7 weight percent of the total mass of the lithium-containing phosphate composite material. The D50 particle size of the lithium ion conductor material in the inner core is 10nm, the average primary particle size of the lithium-containing phosphate composite material is 100nm, and the thickness of the outer shell layer is 2.2nm.
A method for preparing a lithium-containing phosphate composite material, comprising the steps of:
step S1, according to chemical formula Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 The stoichiometric ratio of each element is respectively measured to obtain lithium carbonate (Li 2 CO 3 0.064 mol) 4.73g, alumina (Al 2 O 3 0.015 mol) 1.51g titanium oxide (TiO 2 0.17 mol) 13.58g of monoammonium phosphate (NH) 4 H 2 PO 4 0.30 mol) 34g, and then placing the mixture into a ball mill for ball milling treatment at a speed of 400rpm for 4 hours to obtain a ball grinding material; placing the ball-milling material in a tube furnace, sintering for 1h at 200 ℃, then heating to 700 ℃ at a speed of 4 ℃/min, sintering for 4h, naturally cooling the tube furnace, taking out the material, crushing, heating to 800 ℃ at a speed of 4 ℃/min, sintering for 6h, naturally cooling the tube furnace, taking out the material, crushing to obtain the material with a chemical formula of Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 The particle size of the lithium aluminum titanium phosphate is 10nm.
Step S2, according to the chemical formula LiMn 0.05 Fe 0.95 PO 4 The stoichiometric ratio of each element is respectively measured to be lithium nitrate (LiNO) 3 369.98g, 5.37 mol), iron nitrate (Fe (NO) 3 ) 3 1232.90g of ammonium phosphate ((NH) 4 ) 3 PO 4 800.00g of manganese nitrate (Mn (NO) 3 ) 2 48.01g, 0.27 mol) and 33.85g of sucrose are uniformly mixed, and the self-heating evaporation liquid phase reaction is completed after the natural evaporation of the solvent in the system is completed, thus obtaining the LiMn compound 0.05 Fe 0.95 PO 4 Lithium iron manganese phosphate precursor.
Step S3, mixing the lithium iron manganese phosphate precursor prepared in the step S2 with the lithium ion conductor material prepared in the step S1 according to the mass ratio of 100: mixing in proportion of 0.3, sanding to obtain D50 particle size of 0.6 μm, spray drying at 150deg.C, sintering at 500deg.C for 12 hr in nitrogen atmosphere, cooling naturally in a tube furnace, taking out the material, and pulverizing to obtain core.
And S4, mixing the inner core and the sucrose according to the mass ratio of 100:4, sintering for 6 hours at 700 ℃ in a nitrogen atmosphere in a tube furnace, naturally cooling the tube furnace, and crushing to obtain the lithium-containing phosphate composite material.
Example A2
The embodiment provides a lithium-containing phosphate composite material, which comprises an inner core and an outer shell which are sequentially combined from inside to outside along the radial direction, wherein the material of the inner core comprises a lithium iron manganese phosphate active material and a lithium ion conductor material embedded in the lithium iron manganese phosphate active material, and the chemical formula of the lithium iron manganese phosphate active material is LiMn 0.05 Fe 0.95 PO 4 The chemical formula of the lithium ion conductor material is Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 The outer shell layer includes a carbon layer. The lithium ion conductor material accounts for 1.5 weight percent of the total mass of the lithium-containing phosphate composite material, and the carbon layer accounts for 1.7 weight percent of the total mass of the lithium-containing phosphate composite material. The particle size of the lithium ion conductor material in the inner core is 10nm, the primary particle size of the lithium-containing phosphate composite material is 100nm, and the thickness of the outer shell layer is 2.2nm.
A method for preparing a lithium-containing phosphate composite material, comprising the steps of:
step S1 is the same as step S1 in example A1.
Step S2 is the same as step S2 in embodiment A1.
Step S3 is the same as step S3 in embodiment A1, except that: the mass ratio of the lithium iron manganese phosphate precursor to the lithium ion conductor material is 100:0.91.
step S4 is the same as step S4 in embodiment A1.
Example A3
The embodiment provides a lithium-containing phosphate composite material comprising an inner part sequentially combined from inside to outside along the radial directionThe core and the shell layer, the material of the core comprises a lithium iron manganese phosphate active material and a lithium ion conductor material embedded in the lithium iron manganese phosphate active material, and the chemical formula of the lithium iron manganese phosphate active material is LiMn 0.05 Fe 0.95 PO 4 The chemical formula of the lithium ion conductor material is Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 The outer shell layer includes a carbon layer. The lithium ion conductor material accounts for 3wt% of the total mass of the lithium-containing phosphate composite material, and the carbon layer accounts for 1.7wt% of the total mass of the lithium-containing phosphate composite material. The particle size of the lithium ion conductor material in the inner core is 10nm, the primary particle size of the lithium-containing phosphate composite material is 100nm, and the thickness of the outer shell layer is 2.2nm.
A method for preparing a lithium-containing phosphate composite material, comprising the steps of:
step S1 is the same as step S1 in example A1.
Step S2 is the same as step S2 in embodiment A1.
Step S3 is the same as step S3 in embodiment A1, except that: the mass ratio of the lithium iron manganese phosphate precursor to the lithium ion conductor material is 100:1.86.
step S4 is the same as step S4 in embodiment A1.
Example A4
The embodiment provides a lithium-containing phosphate composite material, which comprises an inner core and an outer shell which are sequentially combined from inside to outside along the radial direction, wherein the material of the inner core comprises a lithium iron manganese phosphate active material and a lithium ion conductor material embedded in the lithium iron manganese phosphate active material, and the chemical formula of the lithium iron manganese phosphate active material is LiMn 0.05 Fe 0.95 PO 4 The chemical formula of the lithium ion conductor material is Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 The outer shell layer includes a carbon layer. The lithium ion conductor material accounts for 4 weight percent of the total mass of the lithium-containing phosphate composite material, and the carbon layer accounts for 1.7 weight percent of the total mass of the lithium-containing phosphate composite material. The particle size of the lithium ion conductor material in the inner core is 10nm, the primary particle size of the lithium-containing phosphate composite material is 100nm, and the thickness of the outer shell layer is 2.2nm.
A method for preparing a lithium-containing phosphate composite material, comprising the steps of:
Step S1 is the same as step S1 in example A1.
Step S2 is the same as step S2 in embodiment A1.
Step S3 is the same as step S3 in embodiment A1, except that: the mass ratio of the lithium iron manganese phosphate precursor to the lithium ion conductor material is 100:2.5.
step S4 is the same as step S4 in embodiment A1.
Example A5
The embodiment provides a lithium-containing phosphate composite material, which comprises an inner core and an outer shell which are sequentially combined from inside to outside along the radial direction, wherein the material of the inner core comprises a lithium iron manganese phosphate active material and a lithium ion conductor material embedded in the lithium iron manganese phosphate active material, and the chemical formula of the lithium iron manganese phosphate active material is LiMn 0.05 Fe 0.95 PO 4 The chemical formula of the lithium ion conductor material is Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 The outer shell layer includes a carbon layer. The lithium ion conductor material accounts for 0.5 weight percent of the total mass of the lithium-containing phosphate composite material, and the carbon layer accounts for 1.7 weight percent of the total mass of the lithium-containing phosphate composite material. The particle size of the lithium ion conductor material in the inner core is 10nm, the primary particle size of the lithium-containing phosphate composite material is 130nm, and the thickness of the outer shell layer is 2.2nm.
A method for preparing a lithium-containing phosphate composite material, comprising the steps of:
step S1 is the same as step S1 in example A1.
Step S2 is the same as step S2 in embodiment A1.
Step S3 is the same as step S3 in embodiment A1.
Step S4 is the same as step S4 in example A1 except that the sintering condition is 750 ℃ for 6 hours.
Example A6
The embodiment provides a lithium-containing phosphate composite material, which comprises an inner core and an outer shell which are sequentially combined from inside to outside along the radial direction, wherein the material of the inner core comprises a lithium manganese iron phosphate active material and a lithium ion conductor embedded in the lithium manganese iron phosphate active materialBulk material, lithium iron manganese phosphate active material with chemical formula of LiMn 0.05 Fe 0.95 PO 4 The chemical formula of the lithium ion conductor material is Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 The outer shell layer includes a carbon layer. The lithium ion conductor material accounts for 0.5 weight percent of the total mass of the lithium-containing phosphate composite material, and the carbon layer accounts for 1.7 weight percent of the total mass of the lithium-containing phosphate composite material. The particle size of the lithium ion conductor material in the inner core is 10nm, the primary particle size of the lithium-containing phosphate composite material is 200nm, and the thickness of the outer shell layer is 2.2nm.
A method for preparing a lithium-containing phosphate composite material, comprising the steps of:
step S1 is the same as step S1 in example A1.
Step S2 is the same as step S2 in embodiment A1.
Step S3 is the same as step S3 in embodiment A1.
Step S4 is the same as step S4 in example A1 except that the sintering condition is 850℃for 6 hours.
Example A7
The embodiment provides a lithium-containing phosphate composite material, which comprises an inner core and an outer shell which are sequentially combined from inside to outside along the radial direction, wherein the material of the inner core comprises a lithium iron manganese phosphate active material and a lithium ion conductor material embedded in the lithium iron manganese phosphate active material, and the chemical formula of the lithium iron manganese phosphate active material is LiMn 0.05 Fe 0.95 PO 4 The chemical formula of the lithium ion conductor material is Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 The outer shell layer includes a carbon layer. The lithium ion conductor material accounts for 0.5 weight percent of the total mass of the lithium-containing phosphate composite material, and the carbon layer accounts for 1.7 weight percent of the total mass of the lithium-containing phosphate composite material. The particle size of the lithium ion conductor material in the inner core is 10nm, the primary particle size of the lithium-containing phosphate composite material is 235nm, and the thickness of the outer shell layer is 2.2nm.
A method for preparing a lithium-containing phosphate composite material, comprising the steps of:
step S1 is the same as step S1 in example A1.
Step S2 is the same as step S2 in embodiment A1.
Step S3 is the same as step S3 in embodiment A1.
Step S4 is the same as step S4 in example A1 except that the sintering condition is 950 ℃ for 6 hours.
Example A8
The embodiment provides a lithium-containing phosphate composite material, which comprises an inner core and an outer shell which are sequentially combined from inside to outside along the radial direction, wherein the material of the inner core comprises a lithium iron manganese phosphate active material and a lithium ion conductor material embedded in the lithium iron manganese phosphate active material, and the chemical formula of the lithium iron manganese phosphate active material is LiMn 0.05 Fe 0.95 PO 4 The chemical formula of the lithium ion conductor material is Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 The outer shell layer includes a carbon layer. The lithium ion conductor material accounts for 0.5 weight percent of the total mass of the lithium-containing phosphate composite material, and the carbon layer accounts for 1.7 weight percent of the total mass of the lithium-containing phosphate composite material. The particle size of the lithium ion conductor material in the inner core is 10nm, the primary particle size of the lithium-containing phosphate composite material is 85nm, and the thickness of the outer shell layer is 2.2nm.
A method for preparing a lithium-containing phosphate composite material, comprising the steps of:
step S1 is the same as step S1 in example A1.
Step S2 is the same as step S2 in embodiment A1.
Step S3 is the same as step S3 in embodiment A1.
Step S4 is the same as step S4 in example A1 except that the sintering condition is 500℃for 6 hours.
Example A9
The embodiment provides a lithium-containing phosphate composite material, which comprises an inner core and an outer shell which are sequentially combined from inside to outside along the radial direction, wherein the material of the inner core comprises a lithium iron manganese phosphate active material and a lithium ion conductor material embedded in the lithium iron manganese phosphate active material, and the chemical formula of the lithium iron manganese phosphate active material is LiMn 0.05 Fe 0.95 PO 4 The chemical formula of the lithium ion conductor material is Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 The outer shell layer includes a carbon layer. The lithium ion conductor material accounts for 0.5 weight percent of the total mass of the lithium-containing phosphate composite material, and the carbon layer accounts for 1.7 weight percent of the total mass of the lithium-containing phosphate composite material. The particle size of the lithium ion conductor material in the inner core is 15nm, the primary particle size of the lithium-containing phosphate composite material is 100nm, and the thickness of the outer shell layer is 2.2nm.
A method for preparing a lithium-containing phosphate composite material, comprising the steps of:
step S1, step S1 in example A1, had a particle size of 15nm.
Step S2 is the same as step S2 in embodiment A1.
Step S3 is the same as step S3 in embodiment A1.
Step S4 is the same as step S4 in embodiment A1.
Example A10
The embodiment provides a lithium-containing phosphate composite material, which comprises an inner core and an outer shell which are sequentially combined from inside to outside along the radial direction, wherein the material of the inner core comprises a lithium iron manganese phosphate active material and a lithium ion conductor material embedded in the lithium iron manganese phosphate active material, and the chemical formula of the lithium iron manganese phosphate active material is LiMn 0.05 Fe 0.95 PO 4 The chemical formula of the lithium ion conductor material is Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 The outer shell layer includes a carbon layer. The lithium ion conductor material accounts for 0.5 weight percent of the total mass of the lithium-containing phosphate composite material, and the carbon layer accounts for 1.7 weight percent of the total mass of the lithium-containing phosphate composite material. The particle size of the lithium ion conductor material in the inner core is 20nm, the primary particle size of the lithium-containing phosphate composite material is 100nm, and the thickness of the outer shell layer is 2.2nm.
A method for preparing a lithium-containing phosphate composite material, comprising the steps of:
step S1, step S1 in example A1, had a particle diameter of 20nm.
Step S2 is the same as step S2 in embodiment A1.
Step S3 is the same as step S3 in embodiment A1.
Step S4 is the same as step S4 in embodiment A1.
Example A11
The embodiment provides a lithium-containing phosphate composite material, which comprises an inner core and an outer shell which are sequentially combined from inside to outside along the radial direction, wherein the material of the inner core comprises a lithium iron manganese phosphate active material and a lithium ion conductor material embedded in the lithium iron manganese phosphate active material, and the chemical formula of the lithium iron manganese phosphate active material is LiMn 0.05 Fe 0.95 PO 4 The chemical formula of the lithium ion conductor material is Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 The outer shell layer includes a carbon layer. The lithium ion conductor material accounts for 0.5 weight percent of the total mass of the lithium-containing phosphate composite material, and the carbon layer accounts for 1.7 weight percent of the total mass of the lithium-containing phosphate composite material. The particle size of the lithium ion conductor material in the inner core is 23nm, the primary particle size of the lithium-containing phosphate composite material is 100nm, and the thickness of the outer shell layer is 2.2nm.
A method for preparing a lithium-containing phosphate composite material, comprising the steps of:
step S1, step S1 in example A1, had a particle size of 23nm.
Step S2 is the same as step S2 in embodiment A1.
Step S3 is the same as step S3 in embodiment A1.
Step S4 is the same as step S4 in embodiment A1.
Example A12
The embodiment provides a lithium-containing phosphate composite material, which comprises an inner core, an intermediate layer and an outer shell layer which are sequentially combined from inside to outside along the radial direction, wherein the material of the inner core comprises a lithium manganese iron phosphate active material (the chemical formula is LiMn 0.05 Fe 0.95 PO 4 ) Lithium ion conductor material (Li) embedded in lithium manganese iron phosphate active material 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 ) The material of the intermediate layer is Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 The outer shell layer includes a carbon layer. The lithium ion conductor material accounted for 3wt% of the total mass of the lithium-containing phosphate composite (wherein the mass ratio of the lithium ion conductor material in the core and the intermediate layer was 6.7:3.3, and the mass of the carbon layer accounted for 1.7wt% of the total mass of the lithium-containing phosphate composite).The particle size of the lithium ion conductor material in the inner core is 10nm, the thickness of the intermediate layer is 0.5nm, the primary particle size of the lithium-containing phosphate composite material is 100nm, and the thickness of the outer shell layer is 2.2nm.
A method for preparing a lithium-containing phosphate composite material, comprising the steps of:
step S1 is the same as step S1 in example A1.
Step S2 is the same as step S2 in embodiment A1.
Step S3 is the same as step S3 in embodiment A1.
And S4, mixing the inner core and the precursor of the lithium ion conductor material according to the mass ratio of 100:0.6, sintering for 7 hours under 800 conditions in a tube furnace under the nitrogen atmosphere, and naturally cooling and crushing the tube furnace to obtain an intermediate material.
And S5, mixing the intermediate material with sucrose according to the mass ratio of 100:4, sintering for 6 hours at 700 ℃ in a nitrogen atmosphere in a tube furnace, naturally cooling the tube furnace, and crushing to obtain the lithium-containing phosphate composite material.
Example A13
The embodiment provides a lithium-containing phosphate composite material, which comprises an inner core, an intermediate layer and an outer shell layer which are sequentially combined from inside to outside along the radial direction, wherein the material of the inner core comprises a lithium manganese iron phosphate active material (the chemical formula is LiMn 0.05 Fe 0.95 PO 4 ) Lithium ion conductor material (Li) embedded in lithium manganese iron phosphate active material 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 ) The material of the intermediate layer is Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 The outer shell layer includes a carbon layer. The lithium ion conductor material accounts for 3wt% of the total mass of the lithium-containing phosphate composite material (wherein the mass ratio of the lithium ion conductor material in the inner core to the lithium ion conductor material in the intermediate layer is 6.5:3.5, and the mass of the carbon layer accounts for 1.7wt% of the total mass of the lithium-containing phosphate composite material), the particle size of the lithium ion conductor material in the inner core is 10nm, the thickness of the intermediate layer is 1.5nm, the primary particle size of the lithium-containing phosphate composite material is 100nm, and the thickness of the outer shell layer is 2.2nm.
A method for preparing a lithium-containing phosphate composite material, comprising the steps of:
step S1 is the same as step S1 in example A1.
Step S2 is the same as step S2 in embodiment A1.
Step S3 is the same as step S3 in embodiment A1.
And S4, mixing the inner core and the precursor of the lithium ion conductor material according to the mass ratio of 100:1.91, sintering for 7 hours at 800 ℃ in a nitrogen atmosphere in a tube furnace, naturally cooling the tube furnace, and crushing to obtain an intermediate material.
Step S5 is the same as step S5 in embodiment a 12.
Example A14
The embodiment provides a lithium-containing phosphate composite material, which comprises an inner core, an intermediate layer and an outer shell layer which are sequentially combined from inside to outside along the radial direction, wherein the material of the inner core comprises a lithium manganese iron phosphate active material (the chemical formula is LiMn 0.05 Fe 0.95 PO 4 ) Lithium ion conductor material (Li) embedded in lithium manganese iron phosphate active material 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 ) The material of the intermediate layer is Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 The outer shell layer includes a carbon layer. The lithium ion conductor material accounts for 3wt% of the total mass of the lithium-containing phosphate composite material (wherein the mass ratio of the lithium ion conductor material in the inner core to the lithium ion conductor material in the intermediate layer is 6:4, and the mass of the carbon layer accounts for 1.7wt% of the total mass of the lithium-containing phosphate composite material).
A method for preparing a lithium-containing phosphate composite material, comprising the steps of:
step S1 is the same as step S1 in example A1.
Step S2 is the same as step S2 in embodiment A1.
Step S3 is the same as step S3 in embodiment A1.
And S4, mixing the inner core and the precursor of the lithium ion conductor material according to the mass ratio of 100:3.85, sintering for 7 hours at 800 ℃ in a nitrogen atmosphere in a tube furnace, naturally cooling the tube furnace, and crushing to obtain an intermediate material.
Step S5 is the same as step S5 in embodiment a 12.
Example A15
The embodiment provides a lithium-containing phosphate composite material, which comprises an inner core, an intermediate layer and an outer shell layer which are sequentially combined from inside to outside along the radial direction, wherein the material of the inner core comprises a lithium manganese iron phosphate active material (the chemical formula is LiMn 0.05 Fe 0.95 PO 4 ) Lithium ion conductor material (Li) embedded in lithium manganese iron phosphate active material 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 ) The material of the intermediate layer is Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 The outer shell layer includes a carbon layer. The lithium ion conductor material accounts for 3wt% of the total mass of the lithium-containing phosphate composite material (wherein the mass ratio of the lithium ion conductor material in the inner core to the lithium ion conductor material in the intermediate layer is 1.8:8.2, and the mass of the carbon layer accounts for 1.7wt% of the total mass of the lithium-containing phosphate composite material). The particle size of the lithium ion conductor material in the inner core is 10nm, the thickness of the intermediate layer is 4.5nm, the primary particle size of the lithium-containing phosphate composite material is 100nm, and the thickness of the outer shell layer is 2.2nm.
A method for preparing a lithium-containing phosphate composite material, comprising the steps of:
step S1 is the same as step S1 in example A1.
Step S2 is the same as step S2 in embodiment A1.
Step S3 is the same as step S3 in embodiment A1.
And S4, mixing the inner core and the precursor of the lithium ion conductor material according to the mass ratio of 100:6.19, sintering for 7 hours at 800 ℃ in a nitrogen atmosphere in a tube furnace, naturally cooling the tube furnace, and crushing to obtain an intermediate material.
Step S5 is the same as step S5 in embodiment a 12.
Example A16
This comparative example provides a method comprising combining an inner core and an outer shell in sequence from inside to outside in the radial direction, wherein the material of the inner core comprises a lithium iron manganese phosphate active material and an inlayLithium ion conductor material in lithium manganese iron phosphate active material, and chemical formula of lithium manganese iron phosphate active material is LiFePO 4 The chemical formula of the lithium ion conductor material is Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 The outer shell layer includes a carbon layer. The lithium ion conductor material in the core accounts for 0.5 weight percent of the total mass of the lithium-containing phosphate composite material, and the carbon layer accounts for 1.7 weight percent of the total mass of the lithium-containing phosphate composite material. The particle size of the lithium ion conductor material is 10nm, the primary particle size of the lithium-containing phosphate composite material is 100nm, and the thickness of the outer shell layer is 2.2nm.
A method for preparing a lithium-containing phosphate composite material, comprising the steps of:
step S1 is the same as step S1 in example A1.
Step S2, liFePO according to the chemical formula 4 The stoichiometric ratio of each element is respectively measured to be lithium nitrate (LiNO) 3 369.98g, 5.37 mol), iron nitrate (Fe (NO) 3 ) 3 1298.75g of ammonium phosphate ((NH) 4 ) 3 PO 4 5.37 mol) of 800.00g of citric acid is added into the solution containing citric acid to be mixed evenly, and when the natural evaporation of the solvent in the system is completed, the self-heating evaporation liquid phase reaction is completed, and the chemical formula of LiFePO is prepared 4 Lithium iron phosphate precursor of (2).
Step S3 differs from step S3 in embodiment A1 in that: the lithium-containing phosphate precursor is replaced with a lithium iron phosphate precursor.
Step S4 is the same as step S4 in embodiment A1.
Example A17
The embodiment provides a lithium-containing phosphate composite material, which comprises an inner core and an outer shell which are sequentially combined from inside to outside along the radial direction, wherein the material of the inner core comprises a lithium iron manganese phosphate active material and a lithium ion conductor material embedded in the lithium iron manganese phosphate active material, and the chemical formula of the lithium iron manganese phosphate active material is LiMn 0.2 Fe 0.8 PO 4 The chemical formula of the lithium ion conductor material is Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 The outer shell layer includes a carbon layer. The lithium ion conductor material accounts for the total mass of the lithium-containing phosphate composite material The mass of the carbon layer accounts for 1.7wt% of the total mass of the lithium-containing phosphate composite material. The particle size of the lithium ion conductor material in the inner core is 10nm, the primary particle size of the lithium-containing phosphate composite material is 100nm, and the thickness of the outer shell layer is 2.2nm.
A method for preparing a lithium-containing phosphate composite material, comprising the steps of:
step S1 is the same as step S1 in example A1.
Step S2, according to the chemical formula LiMn 0.2 Fe 0.8 PO 4 The stoichiometric ratio of each element is respectively measured to be lithium nitrate (LiNO) 3 369.98g, 5.37 mol), iron oxide (Fe 2 O 3 343.00g of ammonium phosphate ((NH) 4 ) 3 PO 4 800g of manganese sulfate (MnSO) 4 162.17g of the mixture (1.07 mol) was added to a solution containing concentrated nitric acid (HNO) 3 The solution with the concentration of 63 weight percent is evenly mixed, and the self-heating evaporation liquid phase reaction is completed after the natural evaporation of the solvent in the system is completed, thus obtaining the LiMn with the chemical formula 0.2 Fe 0.8 PO 4 Lithium iron manganese phosphate precursor.
Step S3 is the same as step S3 in embodiment A1, except that: and (3) replacing the lithium-containing phosphate precursor with the lithium manganese iron phosphate precursor prepared in the step (S2).
Step S4 is the same as step S4 in embodiment A1.
Example A18
The embodiment provides a lithium-containing phosphate composite material, which comprises an inner core and an outer shell which are sequentially combined from inside to outside along the radial direction, wherein the material of the inner core comprises a lithium iron manganese phosphate active material and a lithium ion conductor material embedded in the lithium iron manganese phosphate active material, and the chemical formula of the lithium iron manganese phosphate active material is LiMn 0.05 Fe 0.95 PO 4 The chemical formula of the lithium ion conductor material is Li 3 V 2 (PO 4 ) 3 The outer shell layer includes a carbon layer. The lithium ion conductor material accounts for 0.5 weight percent of the total mass of the lithium-containing phosphate composite material, and the carbon layer accounts for 1.7 weight percent of the total mass of the lithium-containing phosphate composite material. The particle size of the lithium ion conductor material in the inner core is 10nm, and the primary particle size of the lithium-containing phosphate composite material is100nm, the thickness of the outer shell layer was 2.2nm.
A method for preparing a lithium-containing phosphate composite material, comprising the steps of:
step S1, according to chemical formula Li 3 V 2 (PO 4 ) 3 The stoichiometric ratio of each element is respectively measured to obtain lithium carbonate (Li 2 CO 3 11.12g, 0.15 mol), vanadium pentoxide (V 2 O 5 0.10 mol) 18.2g of monoammonium phosphate (NH) 4 H 2 PO 4 0.30 mol) 34g, and then placing the mixture into a ball mill for ball milling treatment at a speed of 400rpm for 4 hours to obtain a ball grinding material; placing the ball-milling material in a tube furnace to sinter for 2 hours at 300 ℃, then heating to 800 ℃ at the speed of 4 ℃/min for 4 hours, naturally cooling the tube furnace, taking out the material, crushing, heating to 900 ℃ at the speed of 4 ℃/min for 6 hours, naturally cooling the tube furnace, taking out the material, crushing to obtain the material with the chemical formula of Li 3 V 2 (PO 4 ) 3 Vanadium lithium phosphate of (a).
Step S2 is the same as step S2 in embodiment A1.
Step S3 is the same as step S3 in embodiment A1, except that: the lithium ion conductor material is replaced with lithium vanadium phosphate.
Step S4 is the same as step S4 in example 1.
Example A19
The embodiment provides a lithium-containing phosphate composite material, which comprises an inner core and an outer shell which are sequentially combined from inside to outside along the radial direction, wherein the material of the inner core comprises a lithium-containing phosphate active material and a lithium ion conductor material embedded in the lithium-containing phosphate active material, and the chemical formula of the lithium-containing phosphate active material is LiMn 0.05 Fe 0.94 Ti 0.01 PO 4 The chemical formula of the lithium ion conductor material is Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 The outer shell layer includes a carbon layer. The lithium ion conductor material accounts for 0.5 weight percent of the total mass of the lithium-containing phosphate composite material, and the carbon layer accounts for 1.7 weight percent of the total mass of the lithium-containing phosphate composite material. The D50 particle size of the lithium ion conductor material in the inner core is 10nm, the average primary particle size of the lithium-containing phosphate composite material is 100nm,the thickness of the outer shell layer was 2.2nm.
A method for preparing a lithium-containing phosphate composite material, comprising the steps of:
step S1 is the same as step S1 in example A1.
Step S2, according to the chemical formula LiMn 0.05 Fe 0.94 Ti 0.01 PO 4 The stoichiometric ratio of each element is respectively measured to be lithium nitrate (LiNO) 3 369.98g, 5.37 mol), iron nitrate (Fe (NO) 3 ) 3 1219.93g of ammonium phosphate ((NH) 4 ) 3 PO 4 800.00g of manganese nitrate (Mn (NO) 3 ) 2 48.01g, 0.27 mol), tetrabutyl titanate (C 16 H 36 O 4 Ti,0.05 mol) 18.26g and sucrose 33.85g are uniformly mixed, and the self-heating evaporation liquid phase reaction is completed after the natural evaporation of the solvent in the system is completed, thus obtaining the LiMn with the chemical formula 0.05 Fe 0.94 Ti 0.01 PO 4 Is a lithium-containing phosphate precursor of (c).
Step S3 is the same as step S3 in embodiment A1.
Step S4 is the same as step S4 in embodiment A1.
Comparative example 1
The comparative example provides a method comprising a radially inner core and an outer shell, which are sequentially bonded from inside to outside, wherein the material of the inner core comprises a lithium iron manganese phosphate active material having the chemical formula LiMn 0.05 Fe 0.95 PO 4 The outer shell layer includes a carbon layer. The mass of the carbon layer accounts for 1.7wt% of the total mass of the lithium-containing phosphate composite material.
A method for preparing a lithium-containing phosphate composite material, comprising the steps of:
step S1, step S2 in example A1, a catalyst having the formula LiMn was obtained 0.05 Fe 0.95 PO 4 Lithium iron manganese phosphate precursor.
S2, performing sanding treatment on a lithium iron manganese phosphate precursor until the D50 particle size is 0.6 mu m, and then performing spray drying at 150 ℃ to obtain an intermediate material;
and S3, sintering the intermediate material in a tube furnace for 12 hours at 500 ℃ in nitrogen atmosphere, taking out the material after the tube furnace is naturally cooled, crushing, mixing the material with sucrose according to the mass ratio of 4:100, sintering for 6 hours at 700 ℃ in the nitrogen atmosphere in the tube furnace, and crushing to obtain the lithium-containing phosphate composite material after the tube furnace is naturally cooled.
Preparation of battery piece and assembly of battery
Positive plate: the positive electrode material active ingredients (lithium-containing phosphate composite material), binder (polyvinylidene fluoride), conductive agent (acetylene black) and solvent (N-methylpyrrolidone solution) provided in examples and comparative examples were mixed according to a ratio of 8:1:1:8, mixing the materials according to the mass ratio, stirring the materials in a vacuum stirrer for 2 hours to obtain positive electrode slurry, uniformly coating the positive electrode slurry on an aluminum foil, drying the aluminum foil in a vacuum drying oven at 120 ℃ for 12 hours, and punching the aluminum foil into a wafer with the thickness of 14mm after rolling to serve as a positive electrode plate.
A counter electrode: a metallic lithium sheet.
A diaphragm: celgard 2400 microporous polypropylene film.
Lithium battery electrolyte: 1mo1/L LiPF 6 Ec+dmc (volume ratio 1:1).
Assembling the button cell:
and assembling the CR2025 button lithium ion battery in a hydrogen atmosphere glove box according to the assembling sequence of the positive plate, the diaphragm, the electrolyte and the metal lithium plate. The batteries including the positive electrode sheets of the lithium-containing phosphate composite materials provided in examples A1 to a19 were respectively referred to as examples S1 to S19, and the batteries including the lithium-containing phosphate composite material of comparative example 1 were referred to as comparative example DS1.
Performance detection
(1) Characterization of physical Properties
The results of scanning electron microscope analysis (SEM) of the lithium-containing phosphate composite material prepared in example 1 are shown in fig. 2. As can be seen from the SEM image in fig. 2, the particles of the lithium-containing phosphate composite are relatively well dispersed.
The lithium-containing phosphate composite material prepared in example 1 was subjected to X-ray diffraction analysis (XRD) results shown in fig. 3. As can be seen from fig. 3, the XRD characteristic peaks of the sample correspond to standard cards, with no impurity phase peaks.
(2) Electrochemical performance test
The electrochemical properties of lithium secondary batteries each composed of examples S1 to S19 and comparative example DS1 were tested.
And (3) low-temperature test: under the condition of-20 ℃, the button cell is respectively subjected to charge and discharge test by a lithium ion battery charge and discharge test system, and the charge and discharge conditions are as follows: the charge termination voltage was 4.3V, the discharge termination voltage was 2.00V, and the charge-discharge current densities were 0.2C and 1C. The results of the related electrochemical performance test of the lithium secondary battery are shown in table 1 below.
And (3) testing at normal temperature, and respectively using a lithium ion battery charge and discharge testing system to perform charge and discharge tests on the button cell at 25+/-0.5 ℃ under the conditions of: the charge termination voltage was 4.3V, the discharge termination voltage was 2.00V, and the charge-discharge current densities were 0.1C and 1C. The results of the related electrochemical performance test of the lithium secondary battery are shown in table 1 below.
And (3) carrying out a cycle test, namely respectively carrying out a charge and discharge test on the button cell by using a lithium ion cell charge and discharge test system under the conditions of 25+/-0.5 ℃ and the charge and discharge conditions: the charge termination voltage is 4.3V, the discharge termination voltage is 2.00V, and the charge-discharge current density is 1C, and the charge-discharge current density is 2000 circles. The results of the related electrochemical performance test of the lithium secondary battery are shown in table 1 below.
As can be seen from table 1, the secondary batteries containing the lithium-containing phosphate composite material prepared in this example application were higher in rate performance, low temperature performance, and cycle performance than the comparative examples. Specifically, it can be found that, in combination with examples S1 to S3, the mass ratio of the lithium ion conductor material is within the preferred range, and the normal-temperature discharge capacity, the low-temperature discharge capacity and the cycle performance thereof are maintained at higher levels, whereas for example S4, the electrochemical performance is slightly worse than other examples due to the excessive mass ratio (exceeding 3 wt%) of the lithium ion conductor material, and the decrease in the normal-temperature discharge capacity is more remarkable. As is clear from the combination of examples S1 and S5 to S8, the primary particle diameter of the lithium-containing phosphate composite material is too high (more than 200 nm), the diffusion rate of lithium ions is reduced, and the cycle performance and the low-temperature performance are deteriorated; too low (below 100 nm), the stability of the crystal structure decreases, the effect on the recycling properties is slightly larger than for samples with too large particle size, the performance decreases more, while the low temperature properties are better than for samples with too large particles. The electrochemical performance of comparative examples S1, S9 to S11 shows a negative correlation with the particle size of the lithium ion conductor material, i.e., the electrochemical performance gradually decreases as the particle size of the lithium ion conductor material increases. In comparison with examples S1 and S12 to S14, the intermediate layer provided between the core and the carbon layer is more advantageous for improving the electrochemical performance of the lithium-containing phosphate composite material, and the low-temperature performance and the cycle performance thereof are both maintained at a better level, and in the case of example S15, since the thickness of the intermediate layer is too high (more than 3 nm), the mass ratio of the lithium ion conductor material in the core and the intermediate layer is too small, the ratio of the active material is reduced and the path of diffusion of lithium ions is increased, resulting in poorer electrochemical performance than in the other examples. As is clear from the comparison of examples S1, S16 to S19, in addition to adding lithium titanium aluminum phosphate as a lithium ion conductor material in the preparation process of the lithium-containing phosphate composite material, other lithium ion conductor materials can be added or doped in the lithium-containing phosphate active material, and the electrochemical performance of the lithium-containing phosphate composite material can be effectively improved.
TABLE 1 electrochemical Performance test results
The foregoing description of the preferred embodiments of the application is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the application.
Claims (11)
1. The lithium-containing phosphate composite material is characterized by comprising an inner core and an outer shell which are combined in sequence from inside to outside along the radial direction, wherein the material of the inner core comprises a lithium-containing phosphate active material and a lithium ion conductor material distributed in the lithium-containing phosphate active material, and the chemical formula of the lithium ion conductor material is Li a M b (PO 4 ) 3 M comprises at least one of Ti, al and V, a is more than or equal to 1 and less than or equal to 3, b is more than or equal to 0.1 and less than or equal to 2, and the shell layer comprises a carbon layer.
2. The lithium-containing phosphate composite of claim 1, wherein the lithium-containing phosphate active material has a chemical formula LiMn x Fe 1-x-y N y PO 4 Wherein N comprises at least one of Ti, al, V, mg, zr, co, ni, si, in, x is more than or equal to 0 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 0.2, and 0 is more than or equal to 1-x-y is more than or equal to 1.
3. The lithium-containing phosphate composite according to claim 2, wherein the lithium-containing phosphate active material is doped with the metal element M in the lithium-ion conductor material, and the metal element M doped in the lithium-containing phosphate active material exists in the form of a single atom.
4. A lithium-containing phosphate composite according to any one of claims 1-3, wherein an intermediate layer is further provided between the inner core and the outer shell, the intermediate layer comprising the lithium ion conductor material.
5. The lithium-containing phosphate composite of claim 4, wherein the lithium ion conductor material in the core and the intermediate layer comprises 0.5wt% to 3wt% of the total mass of the lithium-containing phosphate composite; and/or
The mass ratio of the lithium ion conductor material in the inner core to the lithium ion conductor material in the intermediate layer is 6:4-7:3; and/or
The mass of the carbon layer accounts for 0.8-3 wt% of the total mass of the lithium-containing phosphate composite material; and/or
The primary particle size of the lithium-containing phosphate composite material is 100 nm-200 nm; and/or
The particle size of the lithium ion conductor material in the inner core is 5 nm-20 nm; and/or
The thickness of the intermediate layer is 0.5 nm-3 nm; and/or
The thickness of the outer shell layer is 1 nm-3 nm.
6. A method for preparing a lithium-containing phosphate composite material, comprising the steps of:
providing a lithium-containing phosphate active material precursor, a lithium ion conductor material, and a carbon source;
mixing the lithium-containing phosphate active material precursor with the lithium ion conductor material, and then performing first sintering treatment to enable the lithium ion conductor material to be embedded in the lithium-containing phosphate active material, so as to obtain a core;
And mixing the inner core with the carbon source, and performing second sintering treatment to coat the carbon layer on the surface of the inner core to obtain the lithium-containing phosphate composite material.
7. The method of preparing a lithium-containing phosphate composite according to claim 6, further comprising, prior to mixing the inner core with the carbon source:
and mixing the inner core with the raw materials of the lithium ion conductor material, grinding, and then performing third sintering treatment to ensure that the surface of the inner core is coated with an intermediate layer.
8. The method of preparing a lithium-containing phosphate composite according to claim 6, wherein the lithium-containing phosphate active material precursor has a chemical formula LiMn x Fe 1-x-y N y PO 4 X is more than or equal to 0 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 0.2,0 is more than or equal to 1-x-y is less than 1, and the preparation method of the lithium-containing phosphate active material precursor comprises the following steps:
LiMn according to the chemical formula x Fe 1-x-y N y PO 4 The stoichiometric ratio of the chemical elements is shown, a first raw material comprising a first lithium source, a first phosphorus source, an iron source, a manganese source and an N source is obtained, and the first raw material is mixed and reacted to obtain the lithium-containing phosphate active material precursor, wherein the N source comprises at least one of a titanium source, an aluminum source, a vanadium source, a magnesium source, a zirconium source, a cobalt source, a nickel source, a silicon source and an indium source; and/or
The preparation method of the lithium ion conductor material comprises the following steps:
according to the chemical general formula Li a M b (PO 4 ) 3 The stoichiometric ratio of each element in the mixture is obtainedAnd the second raw material comprises a second lithium source, a second phosphorus source and an M source, and the second raw material is subjected to fourth sintering treatment to obtain the lithium ion conductor material, wherein the M source comprises at least one of an aluminum source, a titanium source and a vanadium source, a is more than or equal to 1 and less than or equal to 3, and b is more than or equal to 0.1 and less than or equal to 2.
9. The method for producing a lithium-containing phosphate composite material according to any one of claim 6 to 8, wherein,
the conditions of the first sintering process include: sintering for 6-12 h in an inert atmosphere with the temperature of 500-700 ℃; and/or
The conditions of the second sintering process include: sintering for 6-12 h in an inert atmosphere with the temperature of 600-900 ℃; and/or
The conditions of the third sintering treatment include: sintering for 6-12 h in an inert atmosphere with the temperature of 700-1000 ℃; and/or
The conditions of the fourth sintering process include: sintering for 1-3 h at 100-300 ℃, then sintering for 4-10 h at 700-1000 ℃, and then sintering for 4-10 h at 800-1000 ℃. And/or
The mass ratio of the lithium-containing phosphate active material precursor to the lithium ion conductor material is 100:0.30 to 1.86; and/or
The mass ratio of the carbon source to the core is 1-5:100.
10. A positive electrode comprising a current collector and a positive electrode active layer bonded to the current collector, wherein the positive electrode active material contained in the positive electrode active layer comprises the lithium-containing phosphate composite material according to any one of claims 1 to 5 and/or the lithium-containing phosphate composite material produced by the method for producing a lithium-containing phosphate composite material according to any one of claims 6 to 9.
11. A secondary battery comprising a positive electrode sheet and a negative electrode sheet, wherein the positive electrode sheet comprises the positive electrode of claim 10.
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