WO2024077965A1 - Positive electrode material and preparation method therefor, and lithium-ion battery - Google Patents
Positive electrode material and preparation method therefor, and lithium-ion battery Download PDFInfo
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- WO2024077965A1 WO2024077965A1 PCT/CN2023/096125 CN2023096125W WO2024077965A1 WO 2024077965 A1 WO2024077965 A1 WO 2024077965A1 CN 2023096125 W CN2023096125 W CN 2023096125W WO 2024077965 A1 WO2024077965 A1 WO 2024077965A1
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- WIPO (PCT)
- Prior art keywords
- positive electrode
- electrode material
- lithium
- slurry
- mxene
- Prior art date
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- 239000007774 positive electrode material Substances 0.000 title claims abstract description 73
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims abstract description 15
- 229910001416 lithium ion Inorganic materials 0.000 title claims abstract description 15
- 238000002360 preparation method Methods 0.000 title abstract description 7
- 239000000463 material Substances 0.000 claims abstract description 66
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 45
- 239000010410 layer Substances 0.000 claims abstract description 42
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 40
- 239000011247 coating layer Substances 0.000 claims abstract description 38
- 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 claims abstract description 26
- 239000002002 slurry Substances 0.000 claims description 48
- RAFWXPDQXCSUBB-UHFFFAOYSA-K [O-]P([O-])([O-])=O.N.[Mn+2].[Fe+2] Chemical compound [O-]P([O-])([O-])=O.N.[Mn+2].[Fe+2] RAFWXPDQXCSUBB-UHFFFAOYSA-K 0.000 claims description 38
- 239000002243 precursor Substances 0.000 claims description 36
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 32
- 239000002244 precipitate Substances 0.000 claims description 27
- 238000000034 method Methods 0.000 claims description 24
- 238000006243 chemical reaction Methods 0.000 claims description 22
- 238000003756 stirring Methods 0.000 claims description 22
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 20
- 229910052744 lithium Inorganic materials 0.000 claims description 20
- 238000001035 drying Methods 0.000 claims description 19
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 19
- 239000000203 mixture Substances 0.000 claims description 17
- 239000011572 manganese Substances 0.000 claims description 16
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 14
- PQXKHYXIUOZZFA-UHFFFAOYSA-M lithium fluoride Chemical compound [Li+].[F-] PQXKHYXIUOZZFA-UHFFFAOYSA-M 0.000 claims description 14
- 239000002245 particle Substances 0.000 claims description 14
- 229910001868 water Inorganic materials 0.000 claims description 14
- 229910052742 iron Inorganic materials 0.000 claims description 13
- 239000000843 powder Substances 0.000 claims description 13
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 12
- 239000002202 Polyethylene glycol Substances 0.000 claims description 12
- 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 claims description 12
- 229920001223 polyethylene glycol Polymers 0.000 claims description 12
- 230000007935 neutral effect Effects 0.000 claims description 11
- 238000000975 co-precipitation Methods 0.000 claims description 10
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 claims description 9
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims description 8
- 229910019142 PO4 Inorganic materials 0.000 claims description 8
- 239000003963 antioxidant agent Substances 0.000 claims description 8
- 230000003078 antioxidant effect Effects 0.000 claims description 8
- 239000010452 phosphate Substances 0.000 claims description 8
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims description 8
- 238000005406 washing Methods 0.000 claims description 8
- 229910052748 manganese Inorganic materials 0.000 claims description 7
- 238000003801 milling Methods 0.000 claims description 7
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims description 6
- 229910021529 ammonia Inorganic materials 0.000 claims description 6
- 239000011248 coating agent Substances 0.000 claims description 4
- 238000000576 coating method Methods 0.000 claims description 4
- 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 claims description 3
- 239000004372 Polyvinyl alcohol Substances 0.000 claims description 3
- 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 claims description 3
- 229930006000 Sucrose Natural products 0.000 claims description 3
- 239000006230 acetylene black Substances 0.000 claims description 3
- 239000012298 atmosphere Substances 0.000 claims description 3
- 238000005056 compaction Methods 0.000 claims description 3
- 238000005260 corrosion Methods 0.000 claims description 3
- 230000007797 corrosion Effects 0.000 claims description 3
- 239000008103 glucose Substances 0.000 claims description 3
- 229910021389 graphene Inorganic materials 0.000 claims description 3
- 229920002451 polyvinyl alcohol Polymers 0.000 claims description 3
- 230000001681 protective effect Effects 0.000 claims description 3
- 239000007787 solid Substances 0.000 claims description 3
- 239000005720 sucrose Substances 0.000 claims description 3
- 238000003825 pressing Methods 0.000 claims 1
- 229910010785 LiFexMn1-xPO4 Inorganic materials 0.000 abstract 1
- 229910010782 LiFexMn1−xPO4 Inorganic materials 0.000 abstract 1
- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Chemical compound OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 description 14
- 230000015572 biosynthetic process Effects 0.000 description 13
- 230000000052 comparative effect Effects 0.000 description 13
- 238000003786 synthesis reaction Methods 0.000 description 13
- 235000003891 ferrous sulphate Nutrition 0.000 description 12
- 239000011790 ferrous sulphate Substances 0.000 description 12
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 12
- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 12
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 11
- 235000011114 ammonium hydroxide Nutrition 0.000 description 11
- 229960001031 glucose Drugs 0.000 description 11
- 239000007921 spray Substances 0.000 description 11
- 229910000616 Ferromanganese Inorganic materials 0.000 description 10
- DALUDRGQOYMVLD-UHFFFAOYSA-N iron manganese Chemical compound [Mn].[Fe] DALUDRGQOYMVLD-UHFFFAOYSA-N 0.000 description 10
- MNNHAPBLZZVQHP-UHFFFAOYSA-N diammonium hydrogen phosphate Chemical compound [NH4+].[NH4+].OP([O-])([O-])=O MNNHAPBLZZVQHP-UHFFFAOYSA-N 0.000 description 9
- 229960005070 ascorbic acid Drugs 0.000 description 7
- 235000010323 ascorbic acid Nutrition 0.000 description 7
- 239000011668 ascorbic acid Substances 0.000 description 7
- 229910000388 diammonium phosphate Inorganic materials 0.000 description 7
- 235000019838 diammonium phosphate Nutrition 0.000 description 7
- 229940099596 manganese sulfate Drugs 0.000 description 7
- 235000007079 manganese sulphate Nutrition 0.000 description 7
- 239000011702 manganese sulphate Substances 0.000 description 7
- SQQMAOCOWKFBNP-UHFFFAOYSA-L manganese(II) sulfate Chemical compound [Mn+2].[O-]S([O-])(=O)=O SQQMAOCOWKFBNP-UHFFFAOYSA-L 0.000 description 7
- 239000000047 product Substances 0.000 description 7
- 238000005245 sintering Methods 0.000 description 7
- 239000005696 Diammonium phosphate Substances 0.000 description 6
- 235000006708 antioxidants Nutrition 0.000 description 6
- 239000008367 deionised water Substances 0.000 description 5
- 229910021641 deionized water Inorganic materials 0.000 description 5
- 230000008021 deposition Effects 0.000 description 5
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 description 5
- 229910052808 lithium carbonate Inorganic materials 0.000 description 5
- 239000012299 nitrogen atmosphere Substances 0.000 description 5
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 4
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 4
- 239000001506 calcium phosphate Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 150000002500 ions Chemical class 0.000 description 4
- 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 4
- NUJOXMJBOLGQSY-UHFFFAOYSA-N manganese dioxide Chemical compound O=[Mn]=O NUJOXMJBOLGQSY-UHFFFAOYSA-N 0.000 description 4
- VASIZKWUTCETSD-UHFFFAOYSA-N oxomanganese Chemical compound [Mn]=O VASIZKWUTCETSD-UHFFFAOYSA-N 0.000 description 4
- 238000011056 performance test Methods 0.000 description 4
- 239000004576 sand Substances 0.000 description 4
- 229910011980 LiFe0.4Mn0.6PO4 Inorganic materials 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 3
- 229910000389 calcium phosphate Inorganic materials 0.000 description 3
- 238000004090 dissolution Methods 0.000 description 3
- 239000003792 electrolyte Substances 0.000 description 3
- AMWRITDGCCNYAT-UHFFFAOYSA-L hydroxy(oxo)manganese;manganese Chemical compound [Mn].O[Mn]=O.O[Mn]=O AMWRITDGCCNYAT-UHFFFAOYSA-L 0.000 description 3
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 239000004254 Ammonium phosphate Substances 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 2
- 239000005955 Ferric phosphate Substances 0.000 description 2
- 229910021578 Iron(III) chloride Inorganic materials 0.000 description 2
- 229910011990 LiFe0.5Mn0.5PO4 Inorganic materials 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-L Phosphate ion(2-) Chemical compound OP([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-L 0.000 description 2
- 101100233916 Saccharomyces cerevisiae (strain ATCC 204508 / S288c) KAR5 gene Proteins 0.000 description 2
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 2
- LFVGISIMTYGQHF-UHFFFAOYSA-N ammonium dihydrogen phosphate Chemical compound [NH4+].OP(O)([O-])=O LFVGISIMTYGQHF-UHFFFAOYSA-N 0.000 description 2
- 229910000148 ammonium phosphate Inorganic materials 0.000 description 2
- 229940010556 ammonium phosphate Drugs 0.000 description 2
- 235000019289 ammonium phosphates Nutrition 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 2
- YYRMJZQKEFZXMX-UHFFFAOYSA-L calcium bis(dihydrogenphosphate) Chemical compound [Ca+2].OP(O)([O-])=O.OP(O)([O-])=O YYRMJZQKEFZXMX-UHFFFAOYSA-L 0.000 description 2
- FUFJGUQYACFECW-UHFFFAOYSA-L calcium hydrogenphosphate Chemical compound [Ca+2].OP([O-])([O-])=O FUFJGUQYACFECW-UHFFFAOYSA-L 0.000 description 2
- 229960001714 calcium phosphate Drugs 0.000 description 2
- 235000011010 calcium phosphates Nutrition 0.000 description 2
- 239000001569 carbon dioxide Substances 0.000 description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-M dihydrogenphosphate Chemical compound OP(O)([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-M 0.000 description 2
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 description 2
- 238000005530 etching Methods 0.000 description 2
- 229940032958 ferric phosphate Drugs 0.000 description 2
- 229940116007 ferrous phosphate Drugs 0.000 description 2
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 description 2
- WBJZTOZJJYAKHQ-UHFFFAOYSA-K iron(3+) phosphate Chemical compound [Fe+3].[O-]P([O-])([O-])=O WBJZTOZJJYAKHQ-UHFFFAOYSA-K 0.000 description 2
- PVFSDGKDKFSOTB-UHFFFAOYSA-K iron(3+);triacetate Chemical compound [Fe+3].CC([O-])=O.CC([O-])=O.CC([O-])=O PVFSDGKDKFSOTB-UHFFFAOYSA-K 0.000 description 2
- 229910000155 iron(II) phosphate Inorganic materials 0.000 description 2
- 229910000399 iron(III) phosphate Inorganic materials 0.000 description 2
- SDEKDNPYZOERBP-UHFFFAOYSA-H iron(ii) phosphate Chemical compound [Fe+2].[Fe+2].[Fe+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O SDEKDNPYZOERBP-UHFFFAOYSA-H 0.000 description 2
- 235000006748 manganese carbonate Nutrition 0.000 description 2
- 239000011656 manganese carbonate Substances 0.000 description 2
- 229940093474 manganese carbonate Drugs 0.000 description 2
- IPJKJLXEVHOKSE-UHFFFAOYSA-L manganese dihydroxide Chemical compound [OH-].[OH-].[Mn+2] IPJKJLXEVHOKSE-UHFFFAOYSA-L 0.000 description 2
- 229910001437 manganese ion Inorganic materials 0.000 description 2
- 229910000016 manganese(II) carbonate Inorganic materials 0.000 description 2
- XMWCXZJXESXBBY-UHFFFAOYSA-L manganese(ii) carbonate Chemical compound [Mn+2].[O-]C([O-])=O XMWCXZJXESXBBY-UHFFFAOYSA-L 0.000 description 2
- 235000019691 monocalcium phosphate Nutrition 0.000 description 2
- JCXJVPUVTGWSNB-UHFFFAOYSA-N nitrogen dioxide Inorganic materials O=[N]=O JCXJVPUVTGWSNB-UHFFFAOYSA-N 0.000 description 2
- 239000010450 olivine Substances 0.000 description 2
- 229910052609 olivine Inorganic materials 0.000 description 2
- NDLPOXTZKUMGOV-UHFFFAOYSA-N oxo(oxoferriooxy)iron hydrate Chemical compound O.O=[Fe]O[Fe]=O NDLPOXTZKUMGOV-UHFFFAOYSA-N 0.000 description 2
- 239000011164 primary particle Substances 0.000 description 2
- 230000001737 promoting effect Effects 0.000 description 2
- 238000007086 side reaction Methods 0.000 description 2
- VKFFEYLSKIYTSJ-UHFFFAOYSA-N tetraazanium;phosphonato phosphate Chemical compound [NH4+].[NH4+].[NH4+].[NH4+].[O-]P([O-])(=O)OP([O-])([O-])=O VKFFEYLSKIYTSJ-UHFFFAOYSA-N 0.000 description 2
- QORWJWZARLRLPR-UHFFFAOYSA-H tricalcium bis(phosphate) Chemical compound [Ca+2].[Ca+2].[Ca+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O QORWJWZARLRLPR-UHFFFAOYSA-H 0.000 description 2
- 235000019739 Dicalciumphosphate Nutrition 0.000 description 1
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 description 1
- 101001121408 Homo sapiens L-amino-acid oxidase Proteins 0.000 description 1
- 101000827703 Homo sapiens Polyphosphoinositide phosphatase Proteins 0.000 description 1
- 102100026388 L-amino-acid oxidase Human genes 0.000 description 1
- 229910001290 LiPF6 Inorganic materials 0.000 description 1
- 102100023591 Polyphosphoinositide phosphatase Human genes 0.000 description 1
- 101100012902 Saccharomyces cerevisiae (strain ATCC 204508 / S288c) FIG2 gene Proteins 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 229910000387 ammonium dihydrogen phosphate Inorganic materials 0.000 description 1
- 229940062672 calcium dihydrogen phosphate Drugs 0.000 description 1
- 150000001721 carbon Chemical class 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 229940038472 dicalcium phosphate Drugs 0.000 description 1
- 229910000390 dicalcium phosphate Inorganic materials 0.000 description 1
- 235000019700 dicalcium phosphate Nutrition 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 125000000524 functional group Chemical group 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 239000011229 interlayer Substances 0.000 description 1
- 239000013067 intermediate product Substances 0.000 description 1
- KVGMATYUUPJFQL-UHFFFAOYSA-N manganese(2+) oxygen(2-) Chemical compound [O--].[O--].[O--].[O--].[Mn++].[Mn++].[Mn++] KVGMATYUUPJFQL-UHFFFAOYSA-N 0.000 description 1
- 235000019837 monoammonium phosphate Nutrition 0.000 description 1
- 229910000150 monocalcium phosphate Inorganic materials 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 235000011007 phosphoric acid Nutrition 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 239000000126 substance Substances 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
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B25/00—Phosphorus; Compounds thereof
- C01B25/16—Oxyacids of phosphorus; Salts thereof
- C01B25/26—Phosphates
- C01B25/45—Phosphates containing plural metal, or metal and ammonium
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/05—Preparation or purification of carbon not covered by groups C01B32/15, C01B32/20, C01B32/25, C01B32/30
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/90—Carbides
- C01B32/914—Carbides of single elements
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/58—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
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2002/00—Crystal-structural characteristics
- C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
- C01P2002/72—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/01—Particle morphology depicted by an image
- C01P2004/03—Particle morphology depicted by an image obtained by SEM
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/80—Particles consisting of a mixture of two or more inorganic phases
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/11—Powder tap density
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/40—Electric properties
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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
-
- 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
Definitions
- the present invention relates to the technical field of lithium ion batteries, and in particular to a positive electrode material and a preparation method thereof, and a lithium ion battery.
- Lithium-ion batteries are widely used in many fields due to their advantages such as high working potential, high specific energy, and environmental friendliness. For example, electric vehicles, computers and other electronic products, etc.
- the active composition especially the composition of the positive electrode material, often plays a decisive role in affecting the performance of lithium-ion batteries.
- lithium iron phosphate with olivine structure Due to its high safety, low cost and high cycle stability, lithium iron phosphate with olivine structure has been successfully industrialized. On this basis, in order to further improve the energy density of lithium iron phosphate, lithium iron manganese phosphate came into being. Compared with lithium iron phosphate, although the energy density of lithium iron manganese phosphate has been improved, its capacity is difficult to volatilize due to its low ionic conductivity. In the prior art, in order to improve the ionic conductivity of lithium iron manganese phosphate materials, carbon coating is usually used to improve the ionic conductivity of lithium iron manganese phosphate materials.
- this carbon-coated lithium iron manganese phosphate positive electrode material has a problem of deteriorating stability of the positive electrode material due to carbon deposition during the charge-discharge process. Therefore, the prior art lacks a positive electrode material with excellent energy density and ionic conductivity.
- the embodiments of the present application provide a positive electrode material and a preparation method thereof, and a lithium-ion battery, which are used to improve the ionic conductivity of a lithium iron manganese phosphate positive electrode material, thereby improving the capacity of the positive electrode material.
- an embodiment of the present application provides a positive electrode material, comprising: an inner layer material and a coating layer coating the inner layer material, the inner layer material is LiFe x Mn 1-x PO 4 , the coating layer comprises Nb 2 C MXene and carbon; wherein 0 ⁇ x ⁇ 0.5.
- the embodiment of the present application coats the lithium iron manganese phosphate material, and on the basis of utilizing the good energy density and stability of lithium iron manganese phosphate, based on the fact that the Nb 2 C MXene coating layer has a two-dimensional graphene-like structure and good mechanical properties, the Nb 2 C MXene coating layer can coat the inner layer material (i.e., the lithium iron manganese phosphate material) in a stacked form, and improve the ionic conductivity of the positive electrode material, thereby improving the capacity of the above-mentioned positive electrode material.
- the inner layer material i.e., the lithium iron manganese phosphate material
- the coating layer can inhibit the side reaction between the lithium iron manganese phosphate material and the electrolyte, thereby improving the stability of the lithium iron manganese phosphate positive electrode material.
- the Nb 2 C MXene coating layer can effectively inhibit the dissolution of manganese ions (Mn 2+ ) in the lithium iron manganese phosphate material in the above-mentioned positive electrode material during the charge-discharge process, thereby alleviating the problem that the continuous dissolution of manganese ions in the charge-discharge process causes the olivine-type lithium iron manganese phosphate material to be unstable in structure, thereby improving the stability of the lithium iron manganese phosphate positive electrode material.
- the Nb2C Mxene in the coating layer is a two-dimensional layered structure
- the two-dimensional layered structure can make the carbon in the coating layer relatively flat and stably distributed in the space between the layers, thereby avoiding the problem of carbon deposition due to the movement of carbon in the coating layer during the charge-discharge process, thereby further improving the stability of the lithium manganese iron phosphate positive electrode material.
- the mass of the coating layer is 15wt%-19wt% of the mass of the inner layer material.
- the mass ratio between the carbon and the Nb 2 C MXene in the coating layer is 2.40:1-4.67:1.
- the coating layer has a thickness of 1-5 nm.
- the compaction density of the positive electrode material is greater than 2.2 g/cm 3 .
- the median particle size of the positive electrode material is 2-30 microns.
- the present application provides a method for preparing a positive electrode material as described in the first aspect and any possible implementation manner, comprising:
- the powder material is sintered at 680-800° C. for 5-20 hours to obtain a positive electrode material.
- the solid content of the first slurry is 30%-80%, and the first slurry is obtained by a stirring device, wherein the rotation speed of the rotor in the stirring device is 1000-3000 rpm.
- the added mass of the carbon source accounts for 12wt% to 14wt% of the mass of the lithium iron manganese phosphate
- the added mass of the Nb2C MXene accounts for 3wt% to 5wt% of the mass of the lithium iron manganese phosphate.
- the lithium iron manganese phosphate is obtained by reacting the ammonia manganese iron phosphate precursor with the lithium source.
- the carbon source is at least one of sucrose, glucose, citric acid, polyvinyl alcohol, polyethylene glycol, carbon black, acetylene black, and graphene.
- the following steps may be further performed:
- the second slurry is filtered, washed and dried to obtain the ammonium manganese iron phosphate precursor; wherein the molecular formula of the ammonium manganese iron phosphate precursor is: NH 4 Mn 1-x Fe x PO 4 ⁇ H2O; 0 ⁇ x ⁇ 0.5.
- the soluble phosphate is at least one of phosphoric acid, ammonium monohydrogen phosphate, ammonium dihydrogen phosphate, calcium dihydrogen phosphate, calcium phosphate, ammonium phosphate, calcium monohydrogen phosphate, and ammonium pyrophosphate.
- the manganese source is at least one of manganese monoxide, manganese dioxide, trimanganese tetroxide, manganese sulfate, manganese carbonate, or manganese hydroxide.
- the iron source is at least one of iron, ferrous sulfate, ferric oxide, ferric acetate, ferric phosphate, ferrous phosphate, ferrous monohydrogen phosphate, ferric dihydrogen phosphate, ferric nitrate, and ferric chloride.
- the coprecipitation reaction is carried out in the presence of an antioxidant;
- the added weight of the antioxidant accounts for 0.4wt%-0.6wt% of the weight of the iron source.
- the antioxidant is ascorbic acid.
- the protective atmosphere of the coprecipitation reaction is at least one of argon, nitrogen and carbon dioxide.
- the following steps may be further included:
- the washed precipitate is dried at -60°C to -20°C to obtain Nb 2 C MXene.
- the present application also provides a lithium-ion battery, including:
- the positive electrode material as described in the first aspect and any possible implementation manner or the positive electrode material obtained by the method as described in the second aspect and any possible implementation manner.
- FIG1 is an electron microscope scanning image of Synthesis Example 1 provided in the examples of the present application.
- FIG2 is a charge-discharge performance test diagram of device Example 1 provided in an embodiment of the present application.
- FIG3 is an electron microscope scanning image of Synthesis Example 2 provided in the examples of the present application.
- FIG4 is a charge-discharge performance test diagram of device embodiment 2 provided in an embodiment of the present application.
- FIG5 is an electron microscope scanning image of Synthesis Example 3 provided in the examples of the present application.
- FIG6 is a charge-discharge performance test diagram of device Example 3 provided in an embodiment of the present application.
- FIG7 is an X-ray diffraction pattern of Synthesis Example 2 provided in the Examples of the present application.
- FIG8 is an electron microscope scanning image of the synthetic comparative example 1 provided in the embodiment of the present application.
- FIG9 is a comparison chart of the charge-discharge performance tests of device example 2, device comparative example 1, and device comparative example 2 provided in the embodiments of the present application.
- the present application proposes a positive electrode material, which includes an inner layer material and a coating layer coating the inner layer material, wherein the inner layer material is LiFe x Mn 1-x PO 4 , and the coating layer includes Nb 2 C MXene and carbon; wherein 0 ⁇ x ⁇ 0.5.
- the Nb 2 C MXene coating layer is coated on the inner layer material and the capacity of the positive electrode material is increased by utilizing the conductivity and mechanical properties of the Nb 2 C MXene coating layer.
- Nb 2 C MXene can also effectively improve the positive electrode material of lithium manganese iron phosphate by inhibiting the side reaction between the inner layer material and the electrolyte and avoiding the dissolution of Mn 2+ , which causes the olivine structure of the positive electrode material to loosen and then collapse.
- the above-mentioned coating layer also includes carbon, so that the electron transmission capacity of the positive electrode material is enhanced during the charge-discharge process.
- the Nb2C MXene in the above-mentioned coating layer is a two-dimensional layered structure of Nb2C
- the carbon is filled in the interlayer of the MXene structure, so that the carbon can be relatively evenly distributed in the coating layer and does not move with the charge-discharge process, thereby avoiding the problem of carbon deposition.
- the thickness of the coating layer is 1-5 nm.
- the mass ratio between carbon in the coating layer and the Nb 2 C MXene is 2.40:1-4.67:1, and the mass of the coating layer is 15wt%-19wt% of the mass of the inner layer material.
- the primary particle size of the positive electrode material when the median particle size of the positive electrode material is 2-30 microns, the primary particle size of the positive electrode material is suitable, and the crystal phase grows completely, so it can show good electron transmission ability during the charge-discharge process. Accordingly, the discharge specific capacity of the positive electrode material corresponding to the lithium-ion battery is greater than 150mAh/g, and the first coulomb efficiency is greater than 95%.
- the compaction density of the positive electrode material is greater than 2.2 g/cm 3 .
- an embodiment of the present application provides a method for preparing the positive electrode material as described above, the method comprising:
- Step 101 sand-milling a first slurry including an ammonium manganese iron phosphate precursor, a lithium source, a carbon source and Nb 2 C MXene to make the median particle size of the first slurry be 0.1-1.0 ⁇ m.
- the molar ratio of the lithium source to the manganese iron phosphate ammonia precursor is 1:1-1:1.06.
- the solvent is water.
- the carbon source accounts for 12 wt% to 14 wt% of the lithium iron manganese phosphate, while the Nb 2 C MXene accounts for 3 wt% to 5 wt% of the lithium iron manganese phosphate.
- the lithium iron manganese phosphate corresponds to the inner layer material in the target product, which is obtained by reacting the ammonium manganese iron phosphate precursor and the lithium source in step 103 .
- the first slurry is obtained in a stirring device (e.g., a stirring kettle).
- the speed of the rotor in the stirring device is 1000-3000 rpm, and the temperature in the stirring device is greater than 50° C.
- the solid content of the first slurry is 30%-80%.
- the carbon source is at least one of sucrose, glucose, citric acid, polyvinyl alcohol, polyethylene glycol, carbon black, acetylene black, and graphene.
- soluble phosphate, ammonia, manganese source and iron source are mixed in water to perform a coprecipitation reaction to generate a second slurry containing a manganese phosphate iron ammonia precursor.
- the molar ratio between the soluble phosphate and ammonia is 1:1 to 1.5-1.
- the molar ratio between the manganese element and the iron element in the manganese source and the iron source relative to ammonia is x:1-x; wherein 0 ⁇ x ⁇ 0.5.
- the soluble phosphate is at least one of phosphoric acid, monoammonium hydrogen phosphate, diammonium phosphate, dicalcium phosphate, calcium phosphate, ammonium phosphate, monocalcium phosphate, and ammonium pyrophosphate.
- the concentration of the soluble phosphate solution is 1.0 mol/L to 1.5 mol/L.
- concentration of ammonia water is 4.5 mol/L to 5.0 mol/L.
- the manganese source is at least one of manganese monoxide, manganese dioxide, trimanganese tetraoxide, manganese sulfate, manganese carbonate, or manganese hydroxide.
- the iron source is at least one of iron, ferrous sulfate, ferric oxide, ferric acetate, ferric phosphate, ferrous phosphate, ferrous monohydrogen phosphate, ferric dihydrogen phosphate, ferric nitrate, and ferric chloride.
- the second slurry is filtered, washed and dried to obtain the manganese iron phosphate ammonia precursor; wherein the molecular formula of the manganese iron phosphate ammonia precursor is: NH 4 Fe x Mn 1-x PO 4 ⁇ H2O; 0 ⁇ x ⁇ 0.5.
- the above-mentioned washing step can wash away impurities such as sulfate ions introduced by the iron source and/or manganese source.
- drying temperature is 80-200° C.
- drying time is 2-12 hours.
- the coprecipitation reaction is carried out in the presence of an antioxidant, wherein the added mass of the antioxidant accounts for 0.4wt%-0.6wt% of the mass of the iron source.
- the antioxidant can be ascorbic acid.
- the protective atmosphere of the above coprecipitation reaction is at least one of argon, nitrogen and carbon dioxide, so as to ensure that any reactant and/or intermediate product does not undergo oxidation reaction during the coprecipitation reaction.
- hydrofluoric acid or a mixture of lithium fluoride and hydrochloric acid is used as an etching solution and dissolved in water together with Nb 2 AlC to perform a corrosion reaction to obtain a third slurry containing Nb 2 C MXene.
- the molar ratio of the solute to Nb 2 AlC in the etching solution is 1:1.05 to 1.5:1.
- Step 102 Dry the first slurry to obtain a powder material.
- the first slurry is dried by a spray dryer.
- Corresponding drying parameters include: air inlet temperature of 150-360°C, air outlet temperature of 70-130°C, and atomizing disk rotation speed of 3000-20000 rpm.
- Step 103 Sinter the powder material at 680-800° C. for 5-20 hours to obtain a positive electrode material.
- the powder material Since the powder material has been ground in step 101, it has the characteristics of small particle size and similar size. Therefore, the crystal phase growth of the powder material is more uniform during the sintering process, which makes the primary particle size in the positive electrode material relatively uniform, thereby improving the electron transmission capacity of the positive electrode material during the charge-discharge process, so that the discharge specific capacity of the positive electrode material corresponding to the lithium-ion battery is greater than 150mAh/g, and the first coulomb efficiency is greater than 95%.
- the inner layer material of the positive electrode material is LiFe x Mn 1-x PO 4 , and the coating layer includes Nb 2 C MXene and carbon, wherein 0 ⁇ x ⁇ 0.5.
- MXene has high conductivity, rich surface Functional groups (e.g., -F, -O, -OH, etc.) and good mechanical properties can be adsorbed on the surface of the inner material in the form of deposition to form a coating layer under the action of lithium ions on the surface of the inner material during the sintering process, thereby promoting the release and embedding of lithium ions in the positive electrode material during the charge-discharge process.
- rich surface Functional groups e.g., -F, -O, -OH, etc.
- the carbon particles can combine with the Nb2C MXene structure and embed into the two-dimensional layered structure of Nb2C MXene, thereby promoting the electron transport capability and avoiding the phenomenon of carbon particles moving on the surface of the inner layer material to cause carbon deposition.
- the inlet air temperature of the spray dryer is 180°C
- the outlet air temperature is 85°C
- the atomizing disk speed is 8000 rpm to obtain a powder material.
- the material is LiFe 0.5 Mn 0.5 PO 4
- the coating layer is Nb 2 C MXene and carbon. Please refer to Figure 1 for the morphology of the positive electrode material.
- the inlet air temperature of the spray dryer is 190°C
- the outlet air temperature is 90°C
- the atomizing disk speed is 10000 rpm to obtain a powder material.
- the inner layer material of the positive electrode material is LiFe 0.4 Mn 0.6 PO 4 , and the coating layer is Nb 2 C MXene and carbon. Please refer to FIG3 for the morphology of the positive electrode material, and refer to FIG7 for the XRD spectrum.
- the inlet air temperature of the spray dryer is 200°C
- the outlet air temperature is 100°C
- the atomizing disk speed is 12000 rpm, to obtain a powder material.
- the inner layer material of the positive electrode material is LiFe 0.5 Mn 0.5 PO 4
- the coating layer is Nb 2 C MXene and carbon. Please refer to FIG5 for the morphology of the positive electrode material.
- the inlet air temperature of the spray dryer is 190°C
- the outlet air temperature is 90°C
- the atomizing disk speed is 10000rpm, to obtain a powder material.
- the inner layer material of the positive electrode material is LiFe 0.4 Mn 0.6 PO 4 , and the coating layer is carbon. Please refer to FIG8 for the morphology of the positive electrode material.
- the inlet air temperature of the spray dryer is 190°C
- the outlet air temperature is 90°C
- the atomizing disk speed is 10000 rpm to obtain a powder material.
- the inner layer material of the positive electrode material is LiFe 0.4 Mn 0.6 PO 4 , and the coating layer is Nb 2 C MXene.
- Device Examples 1-3 and Device Comparative Examples 1-2 are button-type batteries prepared using Synthesis Examples 1-3 and Synthesis Comparative Examples 1-2 as positive electrode materials, respectively.
- the positive electrode sheet in device examples 1-3 and device comparative example 1 is coated with 8-10 mg/ cm2 of positive electrode material on one side relative to the negative electrode sheet, and the positive electrode is a circular aluminum sheet with a diameter of 15MM.
- the electrolyte of device examples 1-3 and device comparative example 1 is 1 mol/L LiPF6 mixed in a mixture of ethylene carbonate and dimethyl carbonate (EC/DMC) with a molar ratio of 1:1.
- the negative electrode is a lithium sheet.
- the discharge capacity and the first coulomb efficiency were tested for the device embodiments 1-3 and the device comparative examples 1-2. Please refer to FIG. 2 , FIG. 4 , FIG. 6 , and FIG. 9 for the test diagrams, and refer to Table 1 for the test data.
Abstract
Directed at the problem of the absence of a positive electrode material with both a good energy density and ionic conductivity in the prior art, the embodiments of the present application provide a positive electrode material and a preparation method therefor, and a lithium-ion battery, so as to improve the ionic conductivity of a lithium manganese iron phosphate positive electrode material, thereby improving the capacity of the positive electrode material. The positive electrode material comprises an inner layer material and a coating layer that coats the inner layer material, wherein the inner layer material is LiFexMn1-xPO4, and the coating layer comprises Nb2C MXene and carbon, where 0 < x ≤ 0.5.
Description
相关申请的交叉引用CROSS-REFERENCE TO RELATED APPLICATIONS
本申请要求在2022年10月12日提交中国专利局、申请号为202211248702.2、申请名称为“一种正极材料及其制备方法、锂离子电池”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。This application claims priority to a Chinese patent application filed with the Chinese Patent Office on October 12, 2022, with application number 202211248702.2 and application name “A positive electrode material, a preparation method thereof, and a lithium-ion battery”, the entire contents of which are incorporated by reference in this application.
本发明涉及锂离子电池技术领域，尤其涉及一种正极材料及其制备方法、锂离子电池。The present invention relates to the technical field of lithium ion batteries, and in particular to a positive electrode material and a preparation method thereof, and a lithium ion battery.
锂离子电池因具备工作电位高、比能量高、环境友好等优势而广泛应用于多个领域之中。例如，电动汽车，电脑等电子产品等等。对于锂离子电池来说，活性组成，尤其是正极材料的组分往往对锂离子电池的性能起到决定性的影响因素。Lithium-ion batteries are widely used in many fields due to their advantages such as high working potential, high specific energy, and environmental friendliness. For example, electric vehicles, computers and other electronic products, etc. For lithium-ion batteries, the active composition, especially the composition of the positive electrode material, often plays a decisive role in affecting the performance of lithium-ion batteries.
由于安全性高、成本低、循环稳定性高，橄榄石型结构的磷酸铁锂已成功实现产业化。在此基础上，为进一步改善磷酸铁锂的能量密度，磷酸锰铁锂应运而生。较之磷酸铁锂，尽管磷酸锰铁锂的能量密度得以提升，但因离子导电率低的原因其容量难以挥发。现有技术中，为了提升磷酸锰铁锂材料的离子导电率通常利用碳包覆的方法提升磷酸铁锰锂材料的离子导电率。然而，这种碳包覆磷酸锰铁锂正极材料在充电-放电过程中，因出现碳沉积现象而致使正极材料出现稳定性恶化的问题。因此，现有技术中缺乏一种能量密度和离子导电率俱佳的正极材料。Due to its high safety, low cost and high cycle stability, lithium iron phosphate with olivine structure has been successfully industrialized. On this basis, in order to further improve the energy density of lithium iron phosphate, lithium iron manganese phosphate came into being. Compared with lithium iron phosphate, although the energy density of lithium iron manganese phosphate has been improved, its capacity is difficult to volatilize due to its low ionic conductivity. In the prior art, in order to improve the ionic conductivity of lithium iron manganese phosphate materials, carbon coating is usually used to improve the ionic conductivity of lithium iron manganese phosphate materials. However, this carbon-coated lithium iron manganese phosphate positive electrode material has a problem of deteriorating stability of the positive electrode material due to carbon deposition during the charge-discharge process. Therefore, the prior art lacks a positive electrode material with excellent energy density and ionic conductivity.
发明内容Summary of the invention
针对现有技术中缺乏一种能量密度和离子导电率俱佳的正极材料的问题，
本申请实施例提供一种正极材料及其制备方法、锂离子电池，用以提升磷酸锰铁锂正极材料的离子导电率，从而使该正极材料的容量得以提升。In view of the problem that the existing technology lacks a positive electrode material with excellent energy density and ion conductivity, The embodiments of the present application provide a positive electrode material and a preparation method thereof, and a lithium-ion battery, which are used to improve the ionic conductivity of a lithium iron manganese phosphate positive electrode material, thereby improving the capacity of the positive electrode material.
第一方面，本申请实施例提供一种正极材料，包括：内层材料和包覆所述内层材料的包覆层，所述内层材料为LiFexMn1-xPO4，所述包覆层包括Nb2C MXene和碳；其中，0＜x≤0.5。In a first aspect, an embodiment of the present application provides a positive electrode material, comprising: an inner layer material and a coating layer coating the inner layer material, the inner layer material is LiFe x Mn 1-x PO 4 , the coating layer comprises Nb 2 C MXene and carbon; wherein 0＜x≤0.5.
本申请实施例通过包覆磷酸锰铁锂材料，在利用磷酸锰铁锂能量密度以及稳定性佳的基础上，基于Nb2C MXene包覆层具备二维类石墨烯结构、良好的力学性能，使得Nb2C MXene包覆层能以层层堆叠的形式包覆内层材料(即磷酸锰铁锂材料)，并提高正极材料的离子导电率，从而提升上述正极材料的容量。同时，包覆层可抑制磷酸锰铁锂材料与电解液之间的副反应，从而提升磷酸锰铁锂正极材料的稳定性。并且，Nb2C MXene包覆层可有效抑制上述正极材料中磷酸锰铁锂材料在充电-放电过程中锰离子(Mn2+)的溶出现象，从而缓解充电-放电过程中，锰离子持续溶出致使橄榄石型的磷酸锰铁锂材料结构不稳定的问题，进而提升磷酸锰铁锂正极材料的稳定性。另外，由于包覆层中Nb2C Mxene为二维层状结构，该二维层状结构可促使包覆层中的碳相对平整且稳定的分布于其层与层之间的空间中，因此可避免充电-放电过程中因包覆层中碳移动而出现碳沉积的问题，从而更进一步提升磷酸锰铁锂正极材料的稳定性。The embodiment of the present application coats the lithium iron manganese phosphate material, and on the basis of utilizing the good energy density and stability of lithium iron manganese phosphate, based on the fact that the Nb 2 C MXene coating layer has a two-dimensional graphene-like structure and good mechanical properties, the Nb 2 C MXene coating layer can coat the inner layer material (i.e., the lithium iron manganese phosphate material) in a stacked form, and improve the ionic conductivity of the positive electrode material, thereby improving the capacity of the above-mentioned positive electrode material. At the same time, the coating layer can inhibit the side reaction between the lithium iron manganese phosphate material and the electrolyte, thereby improving the stability of the lithium iron manganese phosphate positive electrode material. In addition, the Nb 2 C MXene coating layer can effectively inhibit the dissolution of manganese ions (Mn 2+ ) in the lithium iron manganese phosphate material in the above-mentioned positive electrode material during the charge-discharge process, thereby alleviating the problem that the continuous dissolution of manganese ions in the charge-discharge process causes the olivine-type lithium iron manganese phosphate material to be unstable in structure, thereby improving the stability of the lithium iron manganese phosphate positive electrode material. In addition, since the Nb2C Mxene in the coating layer is a two-dimensional layered structure, the two-dimensional layered structure can make the carbon in the coating layer relatively flat and stably distributed in the space between the layers, thereby avoiding the problem of carbon deposition due to the movement of carbon in the coating layer during the charge-discharge process, thereby further improving the stability of the lithium manganese iron phosphate positive electrode material.
一种可能的实施方式，所述包覆层的质量为所述内层材料的质量的15wt％-19wt％。In a possible implementation manner, the mass of the coating layer is 15wt%-19wt% of the mass of the inner layer material.
一种可能的实施方式，所述包覆层中所述碳与所述Nb2C MXene之间的质量比为2.40:1-4.67:1。In a possible implementation manner, the mass ratio between the carbon and the Nb 2 C MXene in the coating layer is 2.40:1-4.67:1.
一种可能的实施方式，所述包覆层的厚度为1-5nm。In a possible implementation manner, the coating layer has a thickness of 1-5 nm.
一种可能的实施方式，所述正极材料的压实密度大于2.2g/cm3。In a possible implementation manner, the compaction density of the positive electrode material is greater than 2.2 g/cm 3 .
一种可能的实施方式，所述正极材料的中位粒径为2-30微米。In a possible implementation manner, the median particle size of the positive electrode material is 2-30 microns.
第二方面，本申请实施例提供一种如第一方面及任一种可能的实施方式所述的正极材料的制备方法，包括：
In a second aspect, the present application provides a method for preparing a positive electrode material as described in the first aspect and any possible implementation manner, comprising:
对包括磷酸锰铁氨前驱体、锂源、碳源和Nb2C MXene的第一浆料进行砂磨，使所述第一浆料的中位粒径为0.1-1.0微米；其中，所述锂源与磷酸锰铁氨的摩尔比为1:1-1:1.06；Sand-milling a first slurry including a manganese iron phosphate ammonium precursor, a lithium source, a carbon source and Nb 2 C MXene to make the median particle size of the first slurry be 0.1-1.0 μm; wherein the molar ratio of the lithium source to the manganese iron phosphate ammonium is 1:1-1:1.06;
对所述第一浆料干燥，得到粉体材料；Drying the first slurry to obtain a powder material;
在680-800℃条件下，对所述粉体材料烧结5-20小时，得到正极材料。The powder material is sintered at 680-800° C. for 5-20 hours to obtain a positive electrode material.
一种可能的实施方式，所述第一浆料的固含量为30％-80％，所述第一浆料通过搅拌设备得到，所述搅拌设备中转子的转速为1000-3000rpm。In a possible implementation manner, the solid content of the first slurry is 30%-80%, and the first slurry is obtained by a stirring device, wherein the rotation speed of the rotor in the stirring device is 1000-3000 rpm.
一种可能的实施方式，所述碳源的添加质量占磷酸锰铁锂质量的12wt％～14wt％，所述Nb2C MXene的添加质量占所述磷酸锰铁锂质量的3wt％～5wt％，所述磷酸锰铁锂由所述磷酸锰铁氨前驱体与所述锂源反应得到。In a possible implementation manner, the added mass of the carbon source accounts for 12wt% to 14wt% of the mass of the lithium iron manganese phosphate, and the added mass of the Nb2C MXene accounts for 3wt% to 5wt% of the mass of the lithium iron manganese phosphate. The lithium iron manganese phosphate is obtained by reacting the ammonia manganese iron phosphate precursor with the lithium source.
一种可能的实施方式，所述碳源为蔗糖、葡萄糖、柠檬酸、聚乙烯醇、聚乙二醇、炭黑、乙炔黑、和石墨烯中的至少一种。In a possible implementation manner, the carbon source is at least one of sucrose, glucose, citric acid, polyvinyl alcohol, polyethylene glycol, carbon black, acetylene black, and graphene.
一种可能的时候方式，所述对包括磷酸锰铁氨前驱体、锂源、碳源和Nb2C MXene的第一浆料进行砂磨之前，还包括：In a possible embodiment, before sand-milling the first slurry including the manganese iron ammonium phosphate precursor, the lithium source, the carbon source and the Nb 2 C MXene, the following steps may be further performed:
在PH值为5-7的条件下，将可溶性磷酸盐、氨、锰源、铁源混合于水中以进行共沉淀反应，生成含磷酸锰铁氨前驱体的第二浆料；Under the condition of pH value of 5-7, soluble phosphate, ammonia, manganese source and iron source are mixed in water to perform a coprecipitation reaction to generate a second slurry containing manganese phosphate iron ammonia precursor;
对所述第二浆料进行压滤、洗涤、干燥，得到所述磷酸锰铁氨前驱体；其中，所述磷酸锰铁氨前驱体的分子通式为：NH4Mn1-xFexPO4·H2O；0＜x≤0.5。The second slurry is filtered, washed and dried to obtain the ammonium manganese iron phosphate precursor; wherein the molecular formula of the ammonium manganese iron phosphate precursor is: NH 4 Mn 1-x Fe x PO 4 ·H2O; 0＜x≤0.5.
一种可能的实施方式，所述可溶性磷酸盐为磷酸、磷酸一氢铵、磷酸二氢铵、磷酸二氢钙、磷酸钙、磷酸铵、磷酸一氢钙、和焦磷酸铵中的至少一种。In a possible implementation manner, the soluble phosphate is at least one of phosphoric acid, ammonium monohydrogen phosphate, ammonium dihydrogen phosphate, calcium dihydrogen phosphate, calcium phosphate, ammonium phosphate, calcium monohydrogen phosphate, and ammonium pyrophosphate.
一种可能的实施方式，所述锰源为一氧化锰、二氧化锰、四氧化三锰、硫酸锰、碳酸锰、或氢氧化锰中的至少一种。In a possible implementation manner, the manganese source is at least one of manganese monoxide, manganese dioxide, trimanganese tetroxide, manganese sulfate, manganese carbonate, or manganese hydroxide.
一种可能的实施方式，所述铁源为铁、硫酸亚铁、氧化铁、醋酸铁、磷酸铁、磷酸亚铁、磷酸一氢铁、磷酸二氢铁、硝酸铁、和氯化铁中的至少一种。In a possible implementation manner, the iron source is at least one of iron, ferrous sulfate, ferric oxide, ferric acetate, ferric phosphate, ferrous phosphate, ferrous monohydrogen phosphate, ferric dihydrogen phosphate, ferric nitrate, and ferric chloride.
一种可能的实施方式，所述共沉淀反应在抗氧化剂存在的条件下进行；
其中，所述抗氧化剂的添加质量占所述铁源的质量的0.4wt％-0.6wt％。In a possible implementation manner, the coprecipitation reaction is carried out in the presence of an antioxidant; The added weight of the antioxidant accounts for 0.4wt%-0.6wt% of the weight of the iron source.
一种可能的实施方式，所述抗氧化剂为抗坏血酸。In a possible implementation manner, the antioxidant is ascorbic acid.
一种可能的实施方式，所述共沉淀反应的保护气氛为氩气、氮气和二氧化碳中的至少一种。In a possible implementation manner, the protective atmosphere of the coprecipitation reaction is at least one of argon, nitrogen and carbon dioxide.
一种可能的实施方式，所述对包括磷酸锰铁氨前驱体、锂源、碳源和Nb2C MXene的第一浆料进行砂磨之前，还包括：In a possible implementation manner, before sand-milling the first slurry including the manganese iron ammonium phosphate precursor, the lithium source, the carbon source and the Nb 2 C MXene, the following steps may be further included:
将氢氟酸或氟化锂和盐酸的混合物与Nb2AlC溶于水中进行腐蚀反应，得到含Nb2C MXene的第三浆料；dissolving hydrofluoric acid or a mixture of lithium fluoride and hydrochloric acid in water with Nb 2 AlC for corrosion reaction to obtain a third slurry containing Nb 2 C MXene;
洗涤所述第三浆料的沉淀，直到所述洗涤溶液为中性；washing the precipitate of the third slurry until the washing solution is neutral;
将洗涤后沉淀在-60℃～-20℃条件下干燥，得到Nb2C MXene。The washed precipitate is dried at -60°C to -20°C to obtain Nb 2 C MXene.
第三方面，本申请实施例还提供一种锂离子电池，包括：In a third aspect, the present application also provides a lithium-ion battery, including:
如第一方面及任一种可能的实施方式所述的正极材料，或如第二方面及任一种可能的实施方式所述方法制得的正极材料。The positive electrode material as described in the first aspect and any possible implementation manner, or the positive electrode material obtained by the method as described in the second aspect and any possible implementation manner.
图1为本申请实施例提供的合成实施例1的电镜扫描图；FIG1 is an electron microscope scanning image of Synthesis Example 1 provided in the examples of the present application;
图2为本申请实施例提供的器件实施例1的充电-放电性能测试图；FIG2 is a charge-discharge performance test diagram of device Example 1 provided in an embodiment of the present application;
图3为本申请实施例提供的合成实施例2的电镜扫描图；FIG3 is an electron microscope scanning image of Synthesis Example 2 provided in the examples of the present application;
图4为本申请实施例提供的器件实施例2的充电-放电性能测试图；FIG4 is a charge-discharge performance test diagram of device embodiment 2 provided in an embodiment of the present application;
图5为本申请实施例提供的合成实施例3的电镜扫描图；FIG5 is an electron microscope scanning image of Synthesis Example 3 provided in the examples of the present application;
图6为本申请实施例提供的器件实施例3的充电-放电性能测试图；FIG6 is a charge-discharge performance test diagram of device Example 3 provided in an embodiment of the present application;
图7为本申请实施例提供的合成实施例2的X射线衍射图谱；FIG7 is an X-ray diffraction pattern of Synthesis Example 2 provided in the Examples of the present application;
图8为本申请实施例提供的合成对比例1的电镜扫描图；FIG8 is an electron microscope scanning image of the synthetic comparative example 1 provided in the embodiment of the present application;
图9为本申请实施例提供的器件实施例2、器件对比例1与器件对比例2充电-放电性能测试的对比图。
FIG9 is a comparison chart of the charge-discharge performance tests of device example 2, device comparative example 1, and device comparative example 2 provided in the embodiments of the present application.
针对现有技术中缺乏一种能量密度和离子导电率俱佳的正极材料的问题，本申请提出一种正极材料，该正极材料包括内层材料和包覆所述内层材料的包覆层，所述内层材料为LiFexMn1-xPO4，所述包覆层包括Nb2C MXene和碳；其中，0＜x≤0.5。在利用内层材料稳定性佳以及能量密度高的基础上，通过Nb2C MXene包覆层的导电性以及力学性能，使之包覆于内层材料上并提升正极材料的容量。同时，Nb2C MXene还可通过抑制内层材料与电解液之间的副反应，并避免Mn2+溶出，致使正极材料的橄榄石型结构松动进而坍塌的现象，有效提升了磷酸锰铁锂的正极此材料。In view of the problem that there is a lack of a positive electrode material with excellent energy density and ion conductivity in the prior art, the present application proposes a positive electrode material, which includes an inner layer material and a coating layer coating the inner layer material, wherein the inner layer material is LiFe x Mn 1-x PO 4 , and the coating layer includes Nb 2 C MXene and carbon; wherein 0＜x≤0.5. On the basis of utilizing the good stability and high energy density of the inner layer material, the Nb 2 C MXene coating layer is coated on the inner layer material and the capacity of the positive electrode material is increased by utilizing the conductivity and mechanical properties of the Nb 2 C MXene coating layer. At the same time, Nb 2 C MXene can also effectively improve the positive electrode material of lithium manganese iron phosphate by inhibiting the side reaction between the inner layer material and the electrolyte and avoiding the dissolution of Mn 2+ , which causes the olivine structure of the positive electrode material to loosen and then collapse.
为进一步提升上述材料的能量密度，在本申请的一种实施例中，上述包覆层中还包括碳，从而使得正极材料在充电-放电过程中电子传输能力增强。同时，由于前述包覆层中的Nb2C MXene为Nb2C二维层状结构，因此当包覆层中含碳时，碳填充于MXene结构的层间，从而可使碳相对均匀的分布在包覆层中，并且不随充电-放电过程而移动，从而避免碳沉积的问题。In order to further improve the energy density of the above-mentioned material, in one embodiment of the present application, the above-mentioned coating layer also includes carbon, so that the electron transmission capacity of the positive electrode material is enhanced during the charge-discharge process. At the same time, since the Nb2C MXene in the above-mentioned coating layer is a two-dimensional layered structure of Nb2C , when the coating layer contains carbon, the carbon is filled in the interlayer of the MXene structure, so that the carbon can be relatively evenly distributed in the coating layer and does not move with the charge-discharge process, thereby avoiding the problem of carbon deposition.
进一步地，上述包覆层的厚度为1-5nm。并且，包覆层中碳与所述Nb2C MXene之间的质量比为2.40:1-4.67:1，包覆层的质量为内层材料的质量的15wt％-19wt％。Furthermore, the thickness of the coating layer is 1-5 nm. Moreover, the mass ratio between carbon in the coating layer and the Nb 2 C MXene is 2.40:1-4.67:1, and the mass of the coating layer is 15wt%-19wt% of the mass of the inner layer material.
在本申请的一种实施例中，当正极材料的中位粒径为2-30微米时，该正极材料的一次颗粒尺寸适宜，晶相生长完全，因此可在充电-放电过程中表现出良好的电子传输能力。相应地，该正极材料对应锂离子电池的放电比容量大于150mAh/g，首次库伦效率大于95％。In one embodiment of the present application, when the median particle size of the positive electrode material is 2-30 microns, the primary particle size of the positive electrode material is suitable, and the crystal phase grows completely, so it can show good electron transmission ability during the charge-discharge process. Accordingly, the discharge specific capacity of the positive electrode material corresponding to the lithium-ion battery is greater than 150mAh/g, and the first coulomb efficiency is greater than 95%.
进一步地，上述正极材料的压实密度大于2.2g/cm3。Furthermore, the compaction density of the positive electrode material is greater than 2.2 g/cm 3 .
基于同一发明构思，本申请实施例提供一种制备如上所述的正极材料的方法，该方法包括：Based on the same inventive concept, an embodiment of the present application provides a method for preparing the positive electrode material as described above, the method comprising:
步骤101：对包括磷酸锰铁氨前驱体、锂源、碳源和Nb2C MXene的第一浆料进行砂磨，使所述第一浆料的中位粒径为0.1-1.0微米。Step 101: sand-milling a first slurry including an ammonium manganese iron phosphate precursor, a lithium source, a carbon source and Nb 2 C MXene to make the median particle size of the first slurry be 0.1-1.0 μm.
其中，所述锂源与磷酸锰铁氨前驱体的摩尔比为1:1-1:1.06。第一浆料的
溶剂为水。The molar ratio of the lithium source to the manganese iron phosphate ammonia precursor is 1:1-1:1.06. The solvent is water.
上述碳源的添加质量占磷酸锰铁锂质量的12wt％～14wt％，而Nb2C MXene的添加质量占所述磷酸锰铁锂质量的3wt％～5wt％。该磷酸锰铁锂对应于目标产物中的内层材料，即由磷酸锰铁氨前驱体和锂源在步骤103中反应得到。The carbon source accounts for 12 wt% to 14 wt% of the lithium iron manganese phosphate, while the Nb 2 C MXene accounts for 3 wt% to 5 wt% of the lithium iron manganese phosphate. The lithium iron manganese phosphate corresponds to the inner layer material in the target product, which is obtained by reacting the ammonium manganese iron phosphate precursor and the lithium source in step 103 .
为使第一浆料中物质混合均匀，且充分反应；在本申请的一种实施例中，上述第一浆料在搅拌设备(例如，搅拌釜)中得到。其中，搅拌设备中转子的转速为1000-3000rpm，搅拌设备中的温度大于50℃。且第一浆料的固含量为30％-80％。In order to make the substances in the first slurry mixed evenly and fully react, in one embodiment of the present application, the first slurry is obtained in a stirring device (e.g., a stirring kettle). The speed of the rotor in the stirring device is 1000-3000 rpm, and the temperature in the stirring device is greater than 50° C. The solid content of the first slurry is 30%-80%.
上述碳源为蔗糖、葡萄糖、柠檬酸、聚乙烯醇、聚乙二醇、炭黑、乙炔黑、和石墨烯中的至少一种。The carbon source is at least one of sucrose, glucose, citric acid, polyvinyl alcohol, polyethylene glycol, carbon black, acetylene black, and graphene.
进一步地，以下针对磷酸锰铁氨前驱体的制备进行说明：Further, the preparation of the manganese iron phosphate ammonia precursor is described below:
首先，在PH值为5-7的条件下，将可溶性磷酸盐、氨、锰源、铁源混合于水中以进行共沉淀反应，生成含磷酸锰铁氨前驱体的第二浆料。上述可溶性磷酸盐与氨之间的摩尔比为1:1～1.5-1。相对于氨，锰源与铁源中锰元素和铁元素之间的摩尔比为x:1-x；其中，0＜x≤0.5。First, under the condition of pH 5-7, soluble phosphate, ammonia, manganese source and iron source are mixed in water to perform a coprecipitation reaction to generate a second slurry containing a manganese phosphate iron ammonia precursor. The molar ratio between the soluble phosphate and ammonia is 1:1 to 1.5-1. The molar ratio between the manganese element and the iron element in the manganese source and the iron source relative to ammonia is x:1-x; wherein 0＜x≤0.5.
上述可溶性磷酸盐为磷酸、磷酸一氢铵、磷酸二氢铵、磷酸二氢钙、磷酸钙、磷酸铵、磷酸一氢钙、和焦磷酸铵中的至少一种。The soluble phosphate is at least one of phosphoric acid, monoammonium hydrogen phosphate, diammonium phosphate, dicalcium phosphate, calcium phosphate, ammonium phosphate, monocalcium phosphate, and ammonium pyrophosphate.
当可溶性磷酸盐溶液以溶液形式添加时，可溶性磷酸盐溶液的浓度为1.0mol/L～1.5mol/L。当氨以溶液形式添加时，氨水浓度为4.5mol/L～5.0mol/L。When the soluble phosphate solution is added in the form of a solution, the concentration of the soluble phosphate solution is 1.0 mol/L to 1.5 mol/L. When ammonia is added in the form of a solution, the concentration of ammonia water is 4.5 mol/L to 5.0 mol/L.
上述锰源为一氧化锰、二氧化锰、四氧化三锰、硫酸锰、碳酸锰、或氢氧化锰中的至少一种。The manganese source is at least one of manganese monoxide, manganese dioxide, trimanganese tetraoxide, manganese sulfate, manganese carbonate, or manganese hydroxide.
上述铁源为铁、硫酸亚铁、氧化铁、醋酸铁、磷酸铁、磷酸亚铁、磷酸一氢铁、磷酸二氢铁、硝酸铁、和氯化铁中的至少一种。The iron source is at least one of iron, ferrous sulfate, ferric oxide, ferric acetate, ferric phosphate, ferrous phosphate, ferrous monohydrogen phosphate, ferric dihydrogen phosphate, ferric nitrate, and ferric chloride.
然后，对所述第二浆料进行压滤、洗涤、干燥，得到所述磷酸锰铁氨前驱体；其中，所述磷酸锰铁氨前驱体的分子通式为：NH4FexMn1-xPO4·H2O；0＜x≤0.5。
Then, the second slurry is filtered, washed and dried to obtain the manganese iron phosphate ammonia precursor; wherein the molecular formula of the manganese iron phosphate ammonia precursor is: NH 4 Fe x Mn 1-x PO 4 ·H2O; 0＜x≤0.5.
上述洗涤步骤可洗去铁源、和/或锰源引入的硫酸根离子等杂质。The above-mentioned washing step can wash away impurities such as sulfate ions introduced by the iron source and/or manganese source.
进一步地，上述干燥的温度为80-200℃，干燥的时间为2-12小时。Furthermore, the drying temperature is 80-200° C., and the drying time is 2-12 hours.
为避免共沉淀反应过程中铁源所引入的Fe2+离子被氧化，而生成Fe3+离子，共沉淀反应在抗氧化剂存在的条件下反应。其中，抗氧化剂的添加质量占所述铁源的质量的0.4wt％-0.6wt％。该抗氧化剂可以为抗坏血酸。In order to prevent the Fe 2+ ions introduced by the iron source from being oxidized and generating Fe 3+ ions during the coprecipitation reaction, the coprecipitation reaction is carried out in the presence of an antioxidant, wherein the added mass of the antioxidant accounts for 0.4wt%-0.6wt% of the mass of the iron source. The antioxidant can be ascorbic acid.
进一步地，上述共沉淀反应的保护气氛为氩气、氮气和二氧化碳中的至少一种，从而确保共沉淀反应过程中任一反应物和/或中间产物不发生氧化反应。Furthermore, the protective atmosphere of the above coprecipitation reaction is at least one of argon, nitrogen and carbon dioxide, so as to ensure that any reactant and/or intermediate product does not undergo oxidation reaction during the coprecipitation reaction.
进一步地，以下针对Nb2C MXene的制备进行说明：Furthermore, the preparation of Nb2C MXene is described below:
首先，将氢氟酸或氟化锂和盐酸的混合物作为刻蚀液，与Nb2AlC共同溶于水中，使之进行腐蚀反应，得到含Nb2C MXene的第三浆料。First, hydrofluoric acid or a mixture of lithium fluoride and hydrochloric acid is used as an etching solution and dissolved in water together with Nb 2 AlC to perform a corrosion reaction to obtain a third slurry containing Nb 2 C MXene.
其中，刻蚀液中溶质与Nb2AlC之间的摩尔比为1:1.05～1.5:1。The molar ratio of the solute to Nb 2 AlC in the etching solution is 1:1.05 to 1.5:1.
然后，洗涤所述第三浆料的沉淀，直到所述洗涤溶液为中性；Then, washing the precipitate of the third slurry until the washing solution is neutral;
最后，将洗涤后沉淀在-60℃～-20℃条件下干燥，得到Nb2C MXene。Finally, the washed precipitate is dried at -60°C to -20°C to obtain Nb 2 C MXene.
步骤102：对所述第一浆料干燥，得到粉体材料。Step 102: Dry the first slurry to obtain a powder material.
上述第一浆料通过喷雾干燥机进行干燥。相应地干燥参数包括：进风温度为150～360℃，出风温度为70～130℃，雾化盘转速为3000～20000rpm。The first slurry is dried by a spray dryer. Corresponding drying parameters include: air inlet temperature of 150-360°C, air outlet temperature of 70-130°C, and atomizing disk rotation speed of 3000-20000 rpm.
步骤103：在680-800℃条件下，对所述粉体材料烧结5-20小时，得到正极材料。Step 103: Sinter the powder material at 680-800° C. for 5-20 hours to obtain a positive electrode material.
由于上述粉体材料在步骤101中进过研磨，因而具备颗粒粒径小，且尺寸相近的特点，因此，上述粉体材料在烧结过程中晶相生长更为均匀，这使得正极材料中一次颗粒尺寸相对均匀，进而提升正极材料在充电-放电过程中的电子传输能力，从而使得上述正极材料对应锂离子电池的放电比容量大于150mAh/g，首次库伦效率大于95％。Since the powder material has been ground in step 101, it has the characteristics of small particle size and similar size. Therefore, the crystal phase growth of the powder material is more uniform during the sintering process, which makes the primary particle size in the positive electrode material relatively uniform, thereby improving the electron transmission capacity of the positive electrode material during the charge-discharge process, so that the discharge specific capacity of the positive electrode material corresponding to the lithium-ion battery is greater than 150mAh/g, and the first coulomb efficiency is greater than 95%.
该正极材料的内层材料为LiFexMn1-xPO4，包覆层包括Nb2C MXene和碳。其中，0＜x≤0.5。The inner layer material of the positive electrode material is LiFe x Mn 1-x PO 4 , and the coating layer includes Nb 2 C MXene and carbon, wherein 0＜x≤0.5.
进一步地，由于MXene作为二维层状材料，具有高导电性、丰富的表面
官能团(例如，-F、-O、-OH等)、和良好的力学性能，因而可在烧结过程中与内层材料表面的锂离子的作用下，以沉积形式吸附于内层材料表面形成包覆层，从而促进正极材料在充电-放电过程中，锂离子的脱出和嵌入。Furthermore, as a two-dimensional layered material, MXene has high conductivity, rich surface Functional groups (e.g., -F, -O, -OH, etc.) and good mechanical properties can be adsorbed on the surface of the inner material in the form of deposition to form a coating layer under the action of lithium ions on the surface of the inner material during the sintering process, thereby promoting the release and embedding of lithium ions in the positive electrode material during the charge-discharge process.
在此基础上，当包覆层中含碳时，碳颗粒可与Nb2C MXene结构结合，嵌入Nb2C MXene的二维层状结构之中，从而在促进电子传输能力的基础上，避免碳颗粒在内层材料表面移动造成碳沉积的现象。On this basis, when the coating layer contains carbon, the carbon particles can combine with the Nb2C MXene structure and embed into the two-dimensional layered structure of Nb2C MXene, thereby promoting the electron transport capability and avoiding the phenomenon of carbon particles moving on the surface of the inner layer material to cause carbon deposition.
以下通过合成实施例1-3，合成对比例1-2以及器件实施例1-3以及器件对比例1-2进行详细说明。The following is a detailed description through Synthesis Examples 1-3, Synthesis Comparative Examples 1-2, Device Examples 1-3 and Device Comparative Examples 1-2.
合成实施例1Synthesis Example 1
S1、以3:7的摩尔比将硫酸亚铁与硫酸锰混合，并添加质量为硫酸亚铁的0.5wt％的抗坏血酸，配置1mol/L的锰铁溶液。将1.2mol/L的磷酸二氢铵溶液(1L)、1.0mol/L的锰铁溶液(1L)、4.8mol/L的氨水(1L)以6.66ml/min的流速加入搅拌釜，使前述溶液在60℃、500rpm的条件下反应3h；反应期间通过控制氨水流速控制搅拌釜中浆料的PH为5，将得到的沉淀压滤、使用去离子水洗涤后，在110℃条件下烘干5h，制得磷酸锰铁氨前驱体。S1. Mix ferrous sulfate and manganese sulfate in a molar ratio of 3:7, add ascorbic acid with a mass of 0.5wt% of ferrous sulfate, and prepare a 1mol/L ferromanganese solution. Add 1.2mol/L diammonium phosphate solution (1L), 1.0mol/L ferromanganese solution (1L), and 4.8mol/L ammonia water (1L) to a stirring tank at a flow rate of 6.66ml/min, and react the above solution at 60°C and 500rpm for 3h; during the reaction, the pH of the slurry in the stirring tank is controlled to 5 by controlling the flow rate of ammonia water, filter the obtained precipitate, wash it with deionized water, and dry it at 110°C for 5h to obtain a manganese iron phosphate ammonia precursor.
S2、将Nb2AlC、氟化锂和盐酸以1:0.8:1的摩尔比在搅拌釜中搅拌12h。其中，搅拌速率为1000rpm，温度为30℃。洗涤反应得到沉淀8次左右，使沉淀表面PH环境为中性，干燥呈中性的沉淀。干燥温度为-45℃，干燥时间24h，得到Nb2C MXene。S2. Stir Nb 2 AlC, lithium fluoride and hydrochloric acid in a stirring tank at a molar ratio of 1:0.8:1 for 12 hours. The stirring rate is 1000 rpm and the temperature is 30°C. Wash the reaction to obtain a precipitate about 8 times to make the pH environment of the precipitate surface neutral, and dry the precipitate to obtain a neutral precipitate. The drying temperature is -45°C and the drying time is 24 hours to obtain Nb 2 C MXene.
S3、将磷酸锰铁氨前驱体和Nb2C MXene、碳酸锂、无水葡萄糖和聚乙二醇混合研磨后溶于水中，在不超过35℃，转速为1800rpm的油浴锅中砂磨，得到中位粒径为0.11μm的浆料。其中，锂源和磷酸锰铁氨前驱体之间的摩尔比为1.02:1，Nb2C MXene为目标产物中内层材料质量的3wt％，无水葡萄糖为前述内层材料质量的4wt％，聚乙二醇为前述内层材料的8wt％。S3. Mix and grind the manganese iron phosphate ammonia precursor, Nb 2 C MXene, lithium carbonate, anhydrous glucose and polyethylene glycol, dissolve in water, and sand grind in an oil bath at a temperature not exceeding 35° C. and a rotation speed of 1800 rpm to obtain a slurry with a median particle size of 0.11 μm. The molar ratio between the lithium source and the manganese iron phosphate ammonia precursor is 1.02:1, Nb 2 C MXene is 3wt% of the mass of the inner layer material in the target product, anhydrous glucose is 4wt% of the mass of the aforementioned inner layer material, and polyethylene glycol is 8wt% of the aforementioned inner layer material.
S4、将上述浆料置于喷雾干燥机中干燥。喷雾干燥机的进风温度为180℃、出风温度为85℃，雾化盘转速为8000rpm，得到粉体材料。S4, placing the slurry in a spray dryer for drying. The inlet air temperature of the spray dryer is 180°C, the outlet air temperature is 85°C, and the atomizing disk speed is 8000 rpm to obtain a powder material.
S5、在氮气气氛中，600℃烧结8h，得到正极材料。该正极材料的内层材
料为LiFe0.5Mn0.5PO4，包覆层为Nb2C MXene和碳。该正极材料的形貌图请参考图1。S5. Sintering at 600°C for 8h in a nitrogen atmosphere to obtain a positive electrode material. The material is LiFe 0.5 Mn 0.5 PO 4 , and the coating layer is Nb 2 C MXene and carbon. Please refer to Figure 1 for the morphology of the positive electrode material.
合成实施例2Synthesis Example 2
S1、以2:3的摩尔比将硫酸亚铁与硫酸锰混合，并添加质量为硫酸亚铁的0.05wt％的抗坏血酸，配置1mol/L的锰铁溶液。将1.4mol/L的磷酸二氢铵溶液(1L)、1.0mol/L的锰铁溶液(1L)、4.8mol/L的氨水(1L)以6.66ml/min的流速加入搅拌釜，使前述溶液在65℃、600rpm的条件下反应4h；反应期间通过控制氨水流速控制搅拌釜中浆料的PH为6，将得到的沉淀压滤、使用去离子水洗涤后，在120℃条件下烘干5h，制得磷酸锰铁氨前驱体。S1. Mix ferrous sulfate and manganese sulfate in a molar ratio of 2:3, add ascorbic acid with a mass of 0.05wt% of ferrous sulfate, and prepare a 1mol/L ferromanganese solution. Add 1.4mol/L diammonium phosphate solution (1L), 1.0mol/L ferromanganese solution (1L), and 4.8mol/L ammonia water (1L) to a stirred tank at a flow rate of 6.66ml/min, and react the above solution at 65°C and 600rpm for 4h; during the reaction, the pH of the slurry in the stirred tank is controlled to 6 by controlling the flow rate of ammonia water, filter the obtained precipitate, wash it with deionized water, and dry it at 120°C for 5h to obtain a manganese iron phosphate ammonia precursor.
S2、将Nb2AlC、氟化锂和盐酸以1:1:1的摩尔比在搅拌釜中搅拌12h。其中，搅拌速率为1200rpm，温度为35℃。洗涤反应得到沉淀8次左右，使沉淀表面PH环境为中性，干燥呈中性的沉淀。干燥温度为-50℃，干燥时间36h，得到Nb2C MXene。S2. Stir Nb 2 AlC, lithium fluoride and hydrochloric acid in a stirring tank at a molar ratio of 1:1:1 for 12 hours. The stirring rate is 1200 rpm and the temperature is 35°C. Wash the reaction to obtain a precipitate about 8 times to make the pH environment of the precipitate surface neutral, and dry the precipitate to obtain a neutral precipitate. The drying temperature is -50°C and the drying time is 36 hours to obtain Nb 2 C MXene.
S3、将磷酸锰铁氨前驱体和Nb2C MXene、碳酸锂、无水葡萄糖和聚乙二醇混合研磨后溶于水中，在不超过40℃，转速为2000rpm的油浴锅中砂磨，得到中位粒径为0.12μm的浆料。其中，锂源和磷酸锰铁氨前驱体之间的摩尔比为1.03:1，Nb2C MXene为目标产物中内层材料质量3.5wt％，无水葡萄糖为前述内层材料质量的4wt％，聚乙二醇为前述内层材料的7wt％。S3. Mix and grind the manganese iron phosphate ammonia precursor, Nb 2 C MXene, lithium carbonate, anhydrous glucose and polyethylene glycol, dissolve in water, and sand grind in an oil bath pot at a temperature not exceeding 40° C. and a rotation speed of 2000 rpm to obtain a slurry with a median particle size of 0.12 μm. The molar ratio between the lithium source and the manganese iron phosphate ammonia precursor is 1.03:1, Nb 2 C MXene is 3.5wt% of the mass of the inner layer material in the target product, anhydrous glucose is 4wt% of the mass of the aforementioned inner layer material, and polyethylene glycol is 7wt% of the aforementioned inner layer material.
S4、将上述浆料置于喷雾干燥机中干燥。喷雾干燥机的进风温度为190℃、出风温度为90℃，雾化盘转速为10000rpm，得到粉体材料。S4, placing the slurry in a spray dryer for drying. The inlet air temperature of the spray dryer is 190°C, the outlet air temperature is 90°C, and the atomizing disk speed is 10000 rpm to obtain a powder material.
S5、在氮气气氛中，650℃烧结9h，得到正极材料。该正极材料的内层材料为LiFe0.4Mn0.6PO4，包覆层为Nb2C MXene和碳。该正极材料的形貌图请参考图3，XRD图谱请参考图7。S5. Sintering at 650° C. for 9 h in a nitrogen atmosphere to obtain a positive electrode material. The inner layer material of the positive electrode material is LiFe 0.4 Mn 0.6 PO 4 , and the coating layer is Nb 2 C MXene and carbon. Please refer to FIG3 for the morphology of the positive electrode material, and refer to FIG7 for the XRD spectrum.
合成实施例3Synthesis Example 3
S1、以1:1的摩尔比将硫酸亚铁与硫酸锰混合，并添加质量为硫酸亚铁的0.05wt％的抗坏血酸，配置1mol/L的锰铁溶液。将1.4mol/L的磷酸二氢铵溶液(1L)、1.0mol/L的锰铁溶液(1L)、4.8mol/L的氨水(1L)以6.68ml/min
的流速加入搅拌釜，使前述溶液在70℃、700rpm的条件下反应5h；反应期间通过控制氨水流速控制搅拌釜中浆料的PH为7，将得到的沉淀压滤、使用去离子水洗涤后，在130℃条件下烘干5h，制得磷酸锰铁氨前驱体。S1. Mix ferrous sulfate and manganese sulfate in a molar ratio of 1:1, and add ascorbic acid at a mass of 0.05wt% of ferrous sulfate to prepare a 1mol/L ferromanganese solution. Mix 1.4mol/L diammonium phosphate solution (1L), 1.0mol/L ferromanganese solution (1L), and 4.8mol/L ammonia water (1L) at 6.68ml/min. The solution was added into the stirring kettle at a flow rate of 70° C. and 700 rpm to react for 5 hours; during the reaction, the pH of the slurry in the stirring kettle was controlled to be 7 by controlling the flow rate of ammonia water. The obtained precipitate was filtered, washed with deionized water, and then dried at 130° C. for 5 hours to obtain an ammonia manganese iron phosphate precursor.
S2、将Nb2AlC、氟化锂和盐酸以1:1.2:1的摩尔比在搅拌釜中搅拌48h。其中，搅拌速率为1400rpm，温度为40℃。洗涤反应得到沉淀8次左右，使沉淀表面PH环境为中性，干燥呈中性的沉淀。干燥温度为-55℃，干燥时间48h，得到Nb2C MXene。S2. Stir Nb 2 AlC, lithium fluoride and hydrochloric acid in a stirring tank at a molar ratio of 1:1.2:1 for 48 hours. The stirring rate is 1400 rpm and the temperature is 40°C. Wash the reaction to obtain a precipitate about 8 times to make the pH environment of the precipitate surface neutral, and dry the precipitate to obtain a neutral precipitate. The drying temperature is -55°C and the drying time is 48 hours to obtain Nb 2 C MXene.
S3、将磷酸锰铁氨前驱体和Nb2C MXene、碳酸锂、无水葡萄糖和聚乙二醇混合研磨后溶于水中，在不超过45℃，转速为2200rpm的油浴锅中砂磨，得到中位粒径为0.14μm的浆料。其中，锂源和磷酸锰铁氨前驱体之间的摩尔比为1.04:1，Nb2C MXene为目标产物中内层材料质量4wt％，无水葡萄糖为前述内层材料质量的4wt％，聚乙二醇为前述内层材料的8wt％。S3. Mix and grind the manganese iron phosphate ammonia precursor, Nb 2 C MXene, lithium carbonate, anhydrous glucose and polyethylene glycol, dissolve in water, and sand grind in an oil bath pot at a temperature not exceeding 45° C. and a rotation speed of 2200 rpm to obtain a slurry with a median particle size of 0.14 μm. The molar ratio between the lithium source and the manganese iron phosphate ammonia precursor is 1.04:1, Nb 2 C MXene is 4wt% of the mass of the inner layer material in the target product, anhydrous glucose is 4wt% of the mass of the aforementioned inner layer material, and polyethylene glycol is 8wt% of the aforementioned inner layer material.
S4、将上述浆料置于喷雾干燥机中干燥。喷雾干燥机的进风温度为200℃、出风温度为100℃，雾化盘转速为12000rpm，得到粉体材料。S4, placing the slurry in a spray dryer for drying. The inlet air temperature of the spray dryer is 200°C, the outlet air temperature is 100°C, and the atomizing disk speed is 12000 rpm, to obtain a powder material.
S5、在氮气气氛中，700℃烧结9h，得到正极材料。该正极材料的内层材料为LiFe0.5Mn0.5PO4，包覆层为Nb2C MXene和碳。该正极材料的形貌图请参考图5。S5. Sintering at 700° C. for 9 h in a nitrogen atmosphere to obtain a positive electrode material. The inner layer material of the positive electrode material is LiFe 0.5 Mn 0.5 PO 4 , and the coating layer is Nb 2 C MXene and carbon. Please refer to FIG5 for the morphology of the positive electrode material.
合成对比例1Comparative Synthesis Example 1
S1、以2:3的摩尔比将硫酸亚铁与硫酸锰混合，并添加质量为硫酸亚铁的0.05wt％的抗坏血酸，配置1mol/L的锰铁溶液。将1.4mol/L的磷酸二氢铵溶液(1L)、1.0mol/L的锰铁溶液(1L)、4.8mol/L的氨水(1L)以6.66ml/min的流速加入搅拌釜，使前述溶液在65℃、600rpm的条件下反应4h；反应期间通过控制氨水流速控制搅拌釜中浆料的PH为6，将得到的沉淀压滤、使用去离子水洗涤后，在120℃条件下烘干5h，制得磷酸锰铁氨前驱体。S1. Mix ferrous sulfate and manganese sulfate in a molar ratio of 2:3, add ascorbic acid with a mass of 0.05wt% of ferrous sulfate, and prepare a 1mol/L ferromanganese solution. Add 1.4mol/L diammonium phosphate solution (1L), 1.0mol/L ferromanganese solution (1L), and 4.8mol/L ammonia water (1L) to a stirred tank at a flow rate of 6.66ml/min, and react the above solution at 65°C and 600rpm for 4h; during the reaction, the pH of the slurry in the stirred tank is controlled to 6 by controlling the flow rate of ammonia water, filter the obtained precipitate, wash it with deionized water, and dry it at 120°C for 5h to obtain a manganese iron phosphate ammonia precursor.
S2、将磷酸锰铁氨前驱体和碳酸锂、无水葡萄糖和聚乙二醇混合研磨后溶于水中，在不超过40℃，转速为2000rpm条件下，砂磨，得到中位粒径为0.12μm的浆料。其中，锂源和磷酸锰铁氨前驱体之间的摩尔比为1.03:1，Nb2C
MXene为目标产物中内层材料质量3.5wt％，无水葡萄糖为前述内层材料质量的4wt％，聚乙二醇为前述内层材料的7wt％。S2. Mix the manganese iron phosphate ammonia precursor, lithium carbonate, anhydrous glucose and polyethylene glycol, grind them, dissolve them in water, and grind them at a temperature not exceeding 40°C and a rotation speed of 2000 rpm to obtain a slurry with a median particle size of 0.12 μm. The molar ratio between the lithium source and the manganese iron phosphate ammonia precursor is 1.03:1, and Nb 2 C MXene accounts for 3.5 wt% of the inner layer material in the target product, anhydrous glucose accounts for 4 wt% of the inner layer material, and polyethylene glycol accounts for 7 wt% of the inner layer material.
S3、将上述浆料置于喷雾干燥机中干燥。喷雾干燥机的进风温度为190℃、出风温度为90℃，雾化盘转速为10000rpm，得到粉体材料。S3, placing the slurry in a spray dryer for drying. The inlet air temperature of the spray dryer is 190°C, the outlet air temperature is 90°C, and the atomizing disk speed is 10000rpm, to obtain a powder material.
S4、在氮气气氛中，700℃烧结9h，得到正极材料。该正极材料的内层材料为LiFe0.4Mn0.6PO4，包覆层为碳。该正极材料的形貌图请参考图8。S4. Sintering at 700°C for 9h in a nitrogen atmosphere to obtain a positive electrode material. The inner layer material of the positive electrode material is LiFe 0.4 Mn 0.6 PO 4 , and the coating layer is carbon. Please refer to FIG8 for the morphology of the positive electrode material.
合成对比例2Comparative Synthesis Example 2
S1、以2:3的摩尔比将硫酸亚铁与硫酸锰混合，并添加质量为硫酸亚铁的0.05wt％的抗坏血酸，配置1mol/L的锰铁溶液。将1.4mol/L的磷酸二氢铵溶液(1L)、1.0mol/L的锰铁溶液(1L)、4.8mol/L的氨水(1L)以6.68ml/min的流速加入搅拌釜，使前述溶液在65℃、600rpm的条件下反应4h；反应期间通过控制氨水流速控制搅拌釜中浆料的PH为6，将得到的沉淀压滤、使用去离子水洗涤后，在120℃条件下烘干5h，制得磷酸锰铁氨前驱体。S1. Mix ferrous sulfate and manganese sulfate in a molar ratio of 2:3, add ascorbic acid with a mass of 0.05wt% of ferrous sulfate, and prepare a 1mol/L ferromanganese solution. Add 1.4mol/L diammonium phosphate solution (1L), 1.0mol/L ferromanganese solution (1L), and 4.8mol/L ammonia water (1L) to a stirring tank at a flow rate of 6.68ml/min, and react the above solution at 65°C and 600rpm for 4h; during the reaction, the pH of the slurry in the stirring tank is controlled to 6 by controlling the flow rate of ammonia water, filter the obtained precipitate, wash it with deionized water, and dry it at 120°C for 5h to obtain a manganese iron phosphate ammonia precursor.
S2、将Nb2AlC、氟化锂和盐酸以1:1:1的摩尔比在搅拌釜中搅拌24h。其中，搅拌速率为1200rpm，温度为35℃。洗涤反应得到沉淀8次左右，使沉淀表面PH环境为中性，干燥呈中性的沉淀。干燥温度为-50℃，干燥时间36h，得到Nb2C MXene。S2. Stir Nb 2 AlC, lithium fluoride and hydrochloric acid in a stirring tank at a molar ratio of 1:1:1 for 24 hours. The stirring rate is 1200 rpm and the temperature is 35°C. Wash the reaction to obtain a precipitate about 8 times to make the pH environment of the precipitate surface neutral, and dry the precipitate to obtain a neutral precipitate. The drying temperature is -50°C and the drying time is 36 hours to obtain Nb 2 C MXene.
S3、将磷酸锰铁氨前驱体和Nb2C MXene、碳酸锂混合研磨后溶于水中，在不超过40℃，转速为2000rpm的油浴锅中砂磨，得到中位粒径为0.12μm的浆料。其中，锂源和磷酸锰铁氨前驱体之间的摩尔比为1.03:1Nb2C MXene为目标产物中内层材料质量3.5wt％，无水葡萄糖为前述内层材料质量的4wt％，聚乙二醇为前述内层材料的7wt％。S3. Mix and grind the manganese iron phosphate ammonia precursor, Nb 2 C MXene and lithium carbonate, dissolve in water, and sand grind in an oil bath at a temperature not exceeding 40° C. and a rotation speed of 2000 rpm to obtain a slurry with a median particle size of 0.12 μm. The molar ratio between the lithium source and the manganese iron phosphate ammonia precursor is 1.03:1. Nb 2 C MXene is 3.5 wt% of the inner layer material in the target product, anhydrous glucose is 4 wt% of the inner layer material, and polyethylene glycol is 7 wt% of the inner layer material.
S4、将上述浆料置于喷雾干燥机中干燥。喷雾干燥机的进风温度为190℃、出风温度为90℃，雾化盘转速为10000rpm，得到粉体材料。S4, placing the slurry in a spray dryer for drying. The inlet air temperature of the spray dryer is 190°C, the outlet air temperature is 90°C, and the atomizing disk speed is 10000 rpm to obtain a powder material.
S5、在氮气气氛中，650℃烧结9h，得到正极材料。该正极材料的内层材料为LiFe0.4Mn0.6PO4，包覆层为Nb2C MXene。S5. Sintering at 650° C. for 9 h in a nitrogen atmosphere to obtain a positive electrode material. The inner layer material of the positive electrode material is LiFe 0.4 Mn 0.6 PO 4 , and the coating layer is Nb 2 C MXene.
器件实施例1-3、器件对比例1-2
Device Examples 1-3, Device Comparative Examples 1-2
器件实施例1-3和器件对比例1-2是分别以合成实施例1-3和合成对比例1-2为正极材料制备的扣式电池。Device Examples 1-3 and Device Comparative Examples 1-2 are button-type batteries prepared using Synthesis Examples 1-3 and Synthesis Comparative Examples 1-2 as positive electrode materials, respectively.
其中，器件实施例1-3，和器件对比例1中的正极片相对于负极片的一侧，各自涂覆8-10mg/cm2的正极材料，该正极为15MM直径的圆形铝片。进一步地，器件实施例1-3，和器件对比例1的电解液为1mol/L LiPF6混合于摩尔比为1:1的碳酸乙烯酯和碳酸二甲酯(EC/DMC)的混合物中。负极就是锂片。Among them, the positive electrode sheet in device examples 1-3 and device comparative example 1 is coated with 8-10 mg/ cm2 of positive electrode material on one side relative to the negative electrode sheet, and the positive electrode is a circular aluminum sheet with a diameter of 15MM. Further, the electrolyte of device examples 1-3 and device comparative example 1 is 1 mol/L LiPF6 mixed in a mixture of ethylene carbonate and dimethyl carbonate (EC/DMC) with a molar ratio of 1:1. The negative electrode is a lithium sheet.
针对器件实施例1-3和器件对比例1-2测试放电容量、首次库伦效率。测试图请参考图2、图4、图6、和图9，测试数据请参考表1。The discharge capacity and the first coulomb efficiency were tested for the device embodiments 1-3 and the device comparative examples 1-2. Please refer to FIG. 2 , FIG. 4 , FIG. 6 , and FIG. 9 for the test diagrams, and refer to Table 1 for the test data.
表1
Table 1
Table 1
由表1可得，器件实施例1-3的放电容量和首次库伦效率均优于器件对比例1-2。As can be seen from Table 1, the discharge capacity and first coulomb efficiency of device embodiments 1-3 are better than those of device comparison examples 1-2.
显然，本领域的技术人员可以对本申请进行各种改动和变型而不脱离本申请的精神和范围。这样，倘若本申请的这些修改和变型属于本申请权利要求及其等同技术的范围之内，则本申请也意图包含这些改动和变型在内。
Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.
Claims (14)
- 一种正极材料，其特征在于，包括：A positive electrode material, characterized by comprising:内层材料和包覆所述内层材料的包覆层，所述内层材料为LiFexMn1-xPO4，所述包覆层包括Nb2C MXene和碳；其中，0＜x≤0.5。An inner layer material and a coating layer coating the inner layer material, wherein the inner layer material is LiFe x Mn 1-x PO 4 , and the coating layer comprises Nb 2 C MXene and carbon; wherein 0<x≤0.5.
- 如权利要求1所述的正极材料，其特征在于，所述包覆层的质量为所述内层材料的质量的15wt％-19wt％。The positive electrode material according to claim 1, characterized in that the mass of the coating layer is 15wt%-19wt% of the mass of the inner layer material.
- 如权利要求1所述的正极材料，其特征在于，所述包覆层中所述碳与所述Nb2C MXene之间的质量比为2.40:1-4.67:1。The positive electrode material according to claim 1, characterized in that the mass ratio between the carbon and the Nb2C MXene in the coating layer is 2.40:1-4.67:1.
- 如权利要求1-3任一项所述的正极材料，其特征在于，所述包覆层的厚度为1-5nm。The positive electrode material according to any one of claims 1 to 3, characterized in that the thickness of the coating layer is 1 to 5 nm.
- 如权利要求4所述的正极材料，其特征在于，所述正极材料的中位粒径为2-30微米。The positive electrode material according to claim 4, characterized in that the median particle size of the positive electrode material is 2-30 microns.
- 如权利要求4所述的正极材料，其特征在于，所述正极材料的压实密度大于2.2g/cm3。The positive electrode material according to claim 4, characterized in that the compaction density of the positive electrode material is greater than 2.2 g/cm 3 .
- 一种如权利要求1-6任一项所述的正极材料的制备方法，其特征在于，包括：A method for preparing a positive electrode material according to any one of claims 1 to 6, characterized in that it comprises:对包括磷酸锰铁氨前驱体、锂源、碳源和Nb2C MXene的第一浆料进行砂磨，使所述第一浆料的中位粒径为0.1-1.0微米；其中，所述锂源与磷酸锰铁氨的摩尔比为1:1-1:1.06；Sand-milling a first slurry including a manganese iron phosphate ammonium precursor, a lithium source, a carbon source and Nb 2 C MXene to make the median particle size of the first slurry be 0.1-1.0 μm; wherein the molar ratio of the lithium source to the manganese iron phosphate ammonium is 1:1-1:1.06;对所述第一浆料干燥，得到粉体材料；Drying the first slurry to obtain a powder material;在680-800℃条件下，对所述粉体材料烧结5-20小时，得到正极材料。The powder material is sintered at 680-800° C. for 5-20 hours to obtain a positive electrode material.
- 如权利要求7所述的方法，其特征在于，所述第一浆料的固含量为30％-80％，所述第一浆料通过搅拌设备得到，所述搅拌设备中转子的转速为1000-3000rpm。The method according to claim 7 is characterized in that the solid content of the first slurry is 30%-80%, the first slurry is obtained by a stirring device, and the rotation speed of the rotor in the stirring device is 1000-3000rpm.
- 如权利要求7所述的方法，其特征在于，所述碳源的添加质量占磷酸锰铁锂质量的12wt％～14wt％，所述Nb2C MXene的添加质量占所述磷酸锰铁 锂质量的3wt％～5wt％，所述磷酸锰铁锂由所述磷酸锰铁氨前驱体与所述锂源反应得到。The method according to claim 7, characterized in that the added mass of the carbon source accounts for 12wt% to 14wt% of the mass of the lithium manganese iron phosphate, and the added mass of the Nb2C MXene accounts for The lithium manganese iron phosphate is 3wt% to 5wt% of the mass of lithium, and the lithium manganese iron phosphate is obtained by reacting the ammonia manganese iron phosphate precursor with the lithium source.
- 如权利要求7所述的方法，其特征在于，所述碳源为蔗糖、葡萄糖、柠檬酸、聚乙烯醇、聚乙二醇、炭黑、乙炔黑、和石墨烯中的至少一种。The method according to claim 7, characterized in that the carbon source is at least one of sucrose, glucose, citric acid, polyvinyl alcohol, polyethylene glycol, carbon black, acetylene black, and graphene.
- 如权利要求8～10任一项所述的方法，其特征在于，所述对包括磷酸锰铁氨前驱体、锂源、碳源和Nb2C MXene的第一浆料进行砂磨之前，还包括：The method according to any one of claims 8 to 10, characterized in that before sand-milling the first slurry comprising the manganese iron ammonium phosphate precursor, the lithium source, the carbon source and the Nb 2 C MXene, it further comprises:在PH值为5-7的条件下，将可溶性磷酸盐、氨、锰源、铁源混合于水中以进行共沉淀反应，生成含磷酸锰铁氨前驱体的第二浆料；Under the condition of pH value of 5-7, soluble phosphate, ammonia, manganese source and iron source are mixed in water to perform a coprecipitation reaction to generate a second slurry containing manganese phosphate iron ammonia precursor;对所述第二浆料进行压滤、洗涤、干燥，得到所述磷酸锰铁氨前驱体；其中，所述磷酸锰铁氨前驱体的分子通式为：NH4Mn1-xFexPO4·H2O；0＜x≤0.5。The second slurry is subjected to filter pressing, washing and drying to obtain the ammonium manganese iron phosphate precursor; wherein the molecular formula of the ammonium manganese iron phosphate precursor is: NH 4 Mn 1-x Fe x PO 4 ·H 2 O; 0＜x≤0.5.
- 如权利要求11所述的方法，其特征在于，所述共沉淀反应在保护气氛中，抗氧化剂存在的条件下进行；其中，所述抗氧化剂的添加质量占所述铁源的质量的0.4wt％-0.6wt％。The method according to claim 11, characterized in that the coprecipitation reaction is carried out in a protective atmosphere in the presence of an antioxidant; wherein the added mass of the antioxidant accounts for 0.4wt%-0.6wt% of the mass of the iron source.
- 如权利要求8～10任一项所述的方法，其特征在于，所述对包括磷酸锰铁氨前驱体、锂源、碳源和Nb2C MXene的第一浆料进行砂磨之前，还包括：The method according to any one of claims 8 to 10, characterized in that before sand-milling the first slurry comprising the manganese iron ammonium phosphate precursor, the lithium source, the carbon source and the Nb 2 C MXene, it further comprises:将氢氟酸或氟化锂和盐酸的混合物与Nb2AlC溶于水中进行腐蚀反应，得到含Nb2C MXene的第三浆料；dissolving hydrofluoric acid or a mixture of lithium fluoride and hydrochloric acid in water with Nb 2 AlC for corrosion reaction to obtain a third slurry containing Nb 2 C MXene;洗涤所述第三浆料的沉淀，直到所述洗涤溶液为中性；washing the precipitate of the third slurry until the washing solution is neutral;将洗涤后沉淀在-60℃～-20℃条件下干燥12-48h，得到Nb2C MXene。The washed precipitate is dried at -60°C to -20°C for 12-48h to obtain Nb 2 C MXene.
- 一种锂离子电池，其特征在于，包括：A lithium-ion battery, comprising:如权利要求1～6任一项所述的正极材料，或如权利要求7～13任一项所述方法制得的正极材料。 The positive electrode material according to any one of claims 1 to 6, or the positive electrode material obtained by the method according to any one of claims 7 to 13.
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