CN117096313A - Lithium iron phosphate composite material and preparation method and application thereof - Google Patents
Lithium iron phosphate composite material and preparation method and application thereof Download PDFInfo
- Publication number
- CN117096313A CN117096313A CN202311172263.6A CN202311172263A CN117096313A CN 117096313 A CN117096313 A CN 117096313A CN 202311172263 A CN202311172263 A CN 202311172263A CN 117096313 A CN117096313 A CN 117096313A
- Authority
- CN
- China
- Prior art keywords
- iron phosphate
- lithium iron
- source
- composite material
- lithium
- 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
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 title claims abstract description 81
- 239000002131 composite material Substances 0.000 title claims abstract description 55
- 238000002360 preparation method Methods 0.000 title abstract description 10
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 61
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 61
- 229910052751 metal Inorganic materials 0.000 claims abstract description 41
- 239000002184 metal Substances 0.000 claims abstract description 41
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims abstract description 20
- 229910052744 lithium Inorganic materials 0.000 claims abstract description 20
- 239000011247 coating layer Substances 0.000 claims abstract description 16
- 239000010410 layer Substances 0.000 claims abstract description 12
- 238000005245 sintering Methods 0.000 claims description 53
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 48
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 46
- 239000002243 precursor Substances 0.000 claims description 38
- 238000000034 method Methods 0.000 claims description 32
- 239000010936 titanium Substances 0.000 claims description 31
- 239000003638 chemical reducing agent Substances 0.000 claims description 24
- 229910052742 iron Inorganic materials 0.000 claims description 24
- 229910052719 titanium Inorganic materials 0.000 claims description 24
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 23
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 20
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims description 15
- 238000002156 mixing Methods 0.000 claims description 15
- 229910052698 phosphorus Inorganic materials 0.000 claims description 15
- 239000011574 phosphorus Substances 0.000 claims description 15
- 239000011259 mixed solution Substances 0.000 claims description 13
- 239000002245 particle Substances 0.000 claims description 13
- 238000010438 heat treatment Methods 0.000 claims description 12
- 229910044991 metal oxide Inorganic materials 0.000 claims description 12
- 150000004706 metal oxides Chemical class 0.000 claims description 12
- 229910052720 vanadium Inorganic materials 0.000 claims description 8
- 239000002904 solvent Substances 0.000 claims description 7
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 claims description 7
- 239000007774 positive electrode material Substances 0.000 claims description 6
- 239000000243 solution Substances 0.000 claims description 3
- 238000000576 coating method Methods 0.000 abstract description 31
- 239000011248 coating agent Substances 0.000 abstract description 26
- 239000000463 material Substances 0.000 abstract description 16
- 230000001351 cycling effect Effects 0.000 abstract description 3
- 239000002052 molecular layer Substances 0.000 abstract description 3
- 229920001046 Nanocellulose Polymers 0.000 description 28
- 238000000498 ball milling Methods 0.000 description 22
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 15
- 235000019441 ethanol Nutrition 0.000 description 15
- 230000008569 process Effects 0.000 description 13
- 239000008367 deionised water Substances 0.000 description 12
- 229910021641 deionized water Inorganic materials 0.000 description 12
- 239000000725 suspension Substances 0.000 description 12
- 239000013078 crystal Substances 0.000 description 10
- 238000001035 drying Methods 0.000 description 10
- 239000002994 raw material Substances 0.000 description 10
- 230000000052 comparative effect Effects 0.000 description 9
- 239000000203 mixture Substances 0.000 description 9
- 239000012299 nitrogen atmosphere Substances 0.000 description 9
- LFVGISIMTYGQHF-UHFFFAOYSA-N ammonium dihydrogen phosphate Chemical compound [NH4+].OP(O)([O-])=O LFVGISIMTYGQHF-UHFFFAOYSA-N 0.000 description 8
- 229910000387 ammonium dihydrogen phosphate Inorganic materials 0.000 description 8
- 125000004429 atom Chemical group 0.000 description 8
- 238000000227 grinding Methods 0.000 description 8
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 description 8
- 229910052808 lithium carbonate Inorganic materials 0.000 description 8
- 235000019837 monoammonium phosphate Nutrition 0.000 description 8
- 239000006012 monoammonium phosphate Substances 0.000 description 8
- 239000002121 nanofiber Substances 0.000 description 8
- 150000002500 ions Chemical class 0.000 description 7
- 238000003756 stirring Methods 0.000 description 7
- -1 titanium ions Chemical class 0.000 description 7
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 6
- 238000006243 chemical reaction Methods 0.000 description 6
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 5
- 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 5
- 239000002019 doping agent Substances 0.000 description 5
- 230000003301 hydrolyzing effect Effects 0.000 description 5
- LIRDHUDRLFDYAI-UHFFFAOYSA-H iron(3+);trisulfite Chemical compound [Fe+3].[Fe+3].[O-]S([O-])=O.[O-]S([O-])=O.[O-]S([O-])=O LIRDHUDRLFDYAI-UHFFFAOYSA-H 0.000 description 5
- 229910001416 lithium ion Inorganic materials 0.000 description 5
- 239000010405 anode material Substances 0.000 description 4
- 229920002678 cellulose Polymers 0.000 description 4
- 239000001913 cellulose Substances 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 239000007790 solid phase Substances 0.000 description 4
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 description 3
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 239000004408 titanium dioxide Substances 0.000 description 3
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 2
- 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 2
- DHMQDGOQFOQNFH-UHFFFAOYSA-N Glycine Chemical compound NCC(O)=O DHMQDGOQFOQNFH-UHFFFAOYSA-N 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 150000001450 anions Chemical class 0.000 description 2
- UNTBPXHCXVWYOI-UHFFFAOYSA-O azanium;oxido(dioxo)vanadium Chemical compound [NH4+].[O-][V](=O)=O UNTBPXHCXVWYOI-UHFFFAOYSA-O 0.000 description 2
- 239000003575 carbonaceous material Substances 0.000 description 2
- 150000001768 cations Chemical class 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 239000011363 dried mixture Substances 0.000 description 2
- 239000003792 electrolyte Substances 0.000 description 2
- 239000008103 glucose Substances 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- FPNCFEPWJLGURZ-UHFFFAOYSA-L iron(2+);sulfite Chemical compound [Fe+2].[O-]S([O-])=O FPNCFEPWJLGURZ-UHFFFAOYSA-L 0.000 description 2
- 229910001386 lithium phosphate Inorganic materials 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 238000004321 preservation Methods 0.000 description 2
- 238000001878 scanning electron micrograph Methods 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- TWQULNDIKKJZPH-UHFFFAOYSA-K trilithium;phosphate Chemical compound [Li+].[Li+].[Li+].[O-]P([O-])([O-])=O TWQULNDIKKJZPH-UHFFFAOYSA-K 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- 239000005696 Diammonium phosphate Substances 0.000 description 1
- 239000004471 Glycine Substances 0.000 description 1
- 229910013870 LiPF 6 Inorganic materials 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- 239000002033 PVDF binder Substances 0.000 description 1
- 239000002202 Polyethylene glycol Substances 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- 229920002125 Sokalan® Polymers 0.000 description 1
- 229920002472 Starch Polymers 0.000 description 1
- 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 1
- 229930006000 Sucrose Natural products 0.000 description 1
- 229910021552 Vanadium(IV) chloride Inorganic materials 0.000 description 1
- PTFCDOFLOPIGGS-UHFFFAOYSA-N Zinc dication Chemical compound [Zn+2] PTFCDOFLOPIGGS-UHFFFAOYSA-N 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 238000010420 art technique Methods 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
- 238000001354 calcination Methods 0.000 description 1
- 210000004027 cell Anatomy 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000009831 deintercalation Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- MNNHAPBLZZVQHP-UHFFFAOYSA-N diammonium hydrogen phosphate Chemical compound [NH4+].[NH4+].OP([O-])([O-])=O MNNHAPBLZZVQHP-UHFFFAOYSA-N 0.000 description 1
- 229910000388 diammonium phosphate Inorganic materials 0.000 description 1
- 235000019838 diammonium phosphate Nutrition 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 229960002089 ferrous chloride Drugs 0.000 description 1
- 229940062993 ferrous oxalate Drugs 0.000 description 1
- 229960001781 ferrous sulfate Drugs 0.000 description 1
- 235000003891 ferrous sulphate Nutrition 0.000 description 1
- 239000011790 ferrous sulphate Substances 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 238000009396 hybridization Methods 0.000 description 1
- NMCUIPGRVMDVDB-UHFFFAOYSA-L iron dichloride Chemical compound Cl[Fe]Cl NMCUIPGRVMDVDB-UHFFFAOYSA-L 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
- OWZIYWAUNZMLRT-UHFFFAOYSA-L iron(2+);oxalate Chemical compound [Fe+2].[O-]C(=O)C([O-])=O OWZIYWAUNZMLRT-UHFFFAOYSA-L 0.000 description 1
- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 1
- 125000001449 isopropyl group Chemical group [H]C([H])([H])C([H])(*)C([H])([H])[H] 0.000 description 1
- XIXADJRWDQXREU-UHFFFAOYSA-M lithium acetate Chemical compound [Li+].CC([O-])=O XIXADJRWDQXREU-UHFFFAOYSA-M 0.000 description 1
- FUJCRWPEOMXPAD-UHFFFAOYSA-N lithium oxide Chemical compound [Li+].[Li+].[O-2] FUJCRWPEOMXPAD-UHFFFAOYSA-N 0.000 description 1
- 229910001947 lithium oxide Inorganic materials 0.000 description 1
- 229910001437 manganese ion Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 210000001724 microfibril Anatomy 0.000 description 1
- 239000012982 microporous membrane Substances 0.000 description 1
- 239000002159 nanocrystal Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000033116 oxidation-reduction process Effects 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 235000011007 phosphoric acid Nutrition 0.000 description 1
- 125000004437 phosphorous atom Chemical group 0.000 description 1
- 239000004584 polyacrylic acid Substances 0.000 description 1
- 229920001223 polyethylene glycol Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 1
- 238000004886 process control Methods 0.000 description 1
- 239000008107 starch Substances 0.000 description 1
- 235000019698 starch Nutrition 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000005720 sucrose Substances 0.000 description 1
- VXUYXOFXAQZZMF-UHFFFAOYSA-N titanium(IV) isopropoxide Chemical compound CC(C)O[Ti](OC(C)C)(OC(C)C)OC(C)C VXUYXOFXAQZZMF-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 229910001456 vanadium ion Inorganic materials 0.000 description 1
- JTJFQBNJBPPZRI-UHFFFAOYSA-J vanadium tetrachloride Chemical compound Cl[V](Cl)(Cl)Cl JTJFQBNJBPPZRI-UHFFFAOYSA-J 0.000 description 1
- UUUGYDOQQLOJQA-UHFFFAOYSA-L vanadyl sulfate Chemical compound [V+2]=O.[O-]S([O-])(=O)=O UUUGYDOQQLOJQA-UHFFFAOYSA-L 0.000 description 1
- 229940041260 vanadyl sulfate Drugs 0.000 description 1
- 229910000352 vanadyl sulfate Inorganic materials 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/362—Composites
- H01M4/366—Composites as layered products
-
- 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
-
- 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
-
- 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
-
- 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
-
- 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
-
- 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
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Composite Materials (AREA)
- Manufacturing & Machinery (AREA)
- Crystallography & Structural Chemistry (AREA)
- Materials Engineering (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
The application relates to the technical field of lithium batteries, in particular to a lithium iron phosphate composite material and a preparation method and application thereof. The composite material sequentially comprises a lithium iron phosphate core, a metal surface doped layer and a carbon coating layer from inside to outside. The application provides a lithium iron phosphate composite material, which belongs to a double-molecular-layer coating material, wherein doped metal is doped on the surface of lithium iron phosphate and then carbon coating is carried out, so that the connection tightness between the doped metal and lithium iron phosphate and carbon is effectively improved, and the conductivity and the cycling stability of the composite material are further improved.
Description
Technical Field
The application relates to the technical field of lithium batteries, in particular to a lithium iron phosphate composite material and a preparation method and application thereof.
Background
In recent years, lithium ion batteries have become widely used power sources for electric vehicles, hybrid vehicles, and portable electronic devices because of their advantages such as high energy density, large operating potential window, lightweight design, and long life. The positive electrode material is used as one of important components of the lithium ion battery, and directly affects the overall cost, safety, energy density and cycle life of the battery. The lithium iron phosphate has the advantages of wide source, low cost, safety, green, stable circulation and the like, and is one of potential anode materials at present; but the application range of lithium iron phosphate is greatly limited due to the one-dimensional lithium ion diffusion and low electron conductivity.
Aiming at the problem of poor conductivity of lithium iron phosphate, the method generally adopts carbon coating, ion doping, process control of particle size and the like to promote improvement of a conductive path and improve conductivity. The carbon coating can not only enhance the conductivity of lithium iron phosphate and improve the kinetics rate of lithium ion deintercalation reaction, but also provide a stable electrochemical interface and greatly improve the electrochemical performance, but in the coating process, the electrochemical performance of the finished product has a great relationship with the tight connection degree between materials, and the conductivity and the circulation stability of the composite material can be directly influenced; and secondly, the particle size of the carbon material also improves the electrochemical performance of the lithium iron phosphate. The ion doping causes holes in a crystal lattice to induce crystal lattice defects, accelerates the conversion from an intrinsic n-type semiconductor to a p-type semiconductor, reduces the charge transfer resistance, improves the oxidation-reduction potential, essentially improves the conductivity and tap density of lithium iron phosphate, and improves the multiplying power and the cycle performance of the material, but has poor doping uniformity in the doping process, so that the stability of the material is greatly changed.
There are also prior art techniques that combine carbon coating technology with ion doping technology, such as such a high tap density lithium iron phosphate positive electrode material as disclosed in the patent document publication No. CN116565180a, and a preparation method and application thereof. The high tap density lithium iron phosphate anode material comprises a carbon coating layer, and a lithium iron phosphate material arranged in the carbon coating layer, wherein the lithium iron phosphate material is an anion and cation co-doped material; the cations include at least one of titanium ions, zinc ions, manganese ions, aluminum ions, and vanadium ions; the anions include at least one of fluoride ions and borate ions. Such a modified lithium iron phosphate positive electrode material disclosed in the publication CN109390563a, a method for producing the same, a positive electrode sheet, and a lithium secondary battery. The modified lithium iron phosphate positive electrode material comprises: a doped lithium iron phosphate core; the coating layer is coated on the surface of the doped lithium iron phosphate inner core; the general formula of the doped lithium iron phosphate core is LiFe alpha M 'beta PO4, alpha is more than or equal to 0.2 and less than or equal to 1, beta is more than or equal to 0 and less than or equal to 0.8, and M' is selected from one of Ti, mg, V, mn, cr, zr, nb, W. In the prior art, two technologies are simply overlapped, and the problems of insufficient compactness of carbon coating and poor uniformity of ion doping still cannot be solved.
Disclosure of Invention
The application aims to solve the problems and provides a lithium iron phosphate composite material, and a preparation method and application thereof.
The technical scheme of the application for solving the problems is that firstly, a lithium iron phosphate composite material is provided, and the composite material sequentially comprises a lithium iron phosphate inner core, a metal surface doping layer and a carbon coating layer from inside to outside.
The application provides a double-molecular-layer coating material, which is characterized in that doped metal is doped on the surface of lithium iron phosphate and then carbon coating is carried out, so that the connection tightness between the doped metal and lithium iron phosphate and carbon is effectively improved, and the conductivity and the cycling stability of the composite material are further improved.
The doping metal used for the metal surface doping layer can be any metal with a defect modification effect, and is preferably selected from one or two of titanium and vanadium. Different doping metals, including titanium, preferably of the present application, have different effects on the tightness of the connection between lithium iron phosphate and carbon.
The carbon source of the carbon coating layer is not limited, but the particle size of the carbon should be limited, and the carbon with small particle size can be more uniformly and tightly coated on the surface of the lithium iron phosphate particles. Preferably, the carbon particle diameter of the carbon used for the carbon coating layer is not more than 1000nm. Preferably not more than 500nm, more preferably not more than 300nm, more preferably not more than 100nm. The nanoscale carbon source is typically derived from nanocellulose and may be referred to as cellulose nanocrystals or/and nanofibrillated cellulose.
Secondly, the application also provides a preparation method of the lithium iron phosphate composite material, which comprises the following steps:
s1, mixing a lithium source, an iron source, a phosphorus source, a doped metal source and a reducing agent, and operating under the condition of converting the doped metal source into doped metal oxide to obtain a precursor;
s2, mixing the precursor with a carbon source, and sintering to obtain the lithium iron phosphate composite material.
In the application, firstly, the precursor of the doped metal oxide is used as the doped metal source, and the precursor of the oxide has better dispersibility, so that the precursor is uniformly dispersed with the lithium source, the iron source and the phosphorus source, thereby improving the ion doping uniformity and stability. Secondly, the surface doping process is that the doped metal oxide is firstly converted into the doped metal oxide for coating and then is mixed with the carbon source, and at the moment, the doped metal is in an ionic state and has better combination property with the carbon source. Thirdly, the doped metal oxide and the carbon source are sintered together to form doped metal and carbon respectively, and in the sintering process, the carbon source can be used as a reducing agent to react with the doped metal oxide, so that the doped metal oxide is reduced into doped metal, and more contact opportunities are provided for the carbon and the doped metal through the joint sintering, so that the reaction efficiency and the combination of the carbon and the doped metal are improved; at the same time, the participation of carbon can reduce the activation energy of the reaction, so that the sintering process can be carried out at a lower temperature.
In step S1, the amount of each raw material has an influence on the properties of the finally produced composite material, and especially the amount of the doping metal should be limited, and as a preference of the present application, in step S1, the molar ratio of the lithium source, the iron source, the phosphorus source, and the doping metal is (1.5-3): 1:1: (0.25-0.3). For example, the molar amount of lithium can be independently 1.5, 1.8, 2.0, 2.2, 2.5, 2.8, 3.0, and the molar amount of doping metal can be independently 0.25, 0.26, 0.27, 0.28, 0.29, 0.30.
The source of the lithium source, the iron source, the phosphorus source, and the doped metal source is not limited, and as a preferred embodiment of the present application, the lithium source is one or more selected from the group consisting of lithium oxide, lithium carbonate, lithium phosphate, lithium acetate, and lithium hydroxide. Preferably, the iron source is selected from one or more of ferrous sulfate, ferrous oxalate, ferrous chloride and ferrous glycine. Preferably, the phosphorus source is selected from one or more of phosphoric acid, monoammonium phosphate, diammonium phosphate and lithium phosphate. Preferably, the doped metal source is selected from one or two of a titanium source and a vanadium source. The titanium source is selected from one or more of tetrabutyl titanate, isopropyl triisostearate titanate and isopropyl titanate. The vanadium source is one or more selected from ammonium metavanadate, vanadium tetrachloride and vanadyl sulfate.
The function of the reducing agent is to prevent oxidation of the ferrous iron, the reducing agent is preferably in excess with respect to the iron, but the excessive amount of reducing agent affects the final composite properties, as a preferred aspect of the application, the molar ratio of reducing agent to iron is (1-1.05): 1. for example, 1:1, 1.01:1, 1.02:1, 1.03:1, 1.04:1, 1.05:1.
The choice of reducing agent is not limited, and is preferably an organic reducing agent, preventing other inorganic elements from adversely affecting the material. The reducing agent can be one or more of glucose, sucrose, citric acid, starch, polyethylene glycol, polyacrylic acid, polyvinyl alcohol and nanocellulose.
The reaction conditions that enable the conversion of the dopant metal source into the dopant metal oxide are related to the specifically selected dopant metal, and as a preferred aspect of the application, in step S1, the conditions include a heat treatment by which the dopant metal source is promoted to decompose into the dopant metal oxide, avoiding the introduction of other substances into the feedstock.
The heat treatment may be hydrothermal, solvothermal, sintering, etc., and is, in view of the influence of temperature, preferably solvothermal treatment in which: the solvent comprises a mixed solution of an alcohol solvent and water, and the treatment temperature is 40-60 ℃.
As the preferable method, the method also comprises a ball milling step, wherein the rotating speed is 350-450r/min, and the ball milling time is 4-5h. Improves the mixing uniformity of the raw materials through ball milling,
in step S2, the amounts of the carbon source and the precursor are not limited, and preferably the mass ratio of the carbon source to the precursor is (2-10): 100, for example, may be 2: 100. 3: 100. 4: 100. 5:100. 6: 100. 7: 100. 8:100 or 10:100, etc. Preferably, the mass ratio of the carbon source to the precursor is 5:100.
The mixing mode of the carbon source and the precursor is not limited, and wet coating or solid phase coating may be used, and the precursor is preferably mixed with an alcohol solution of the carbon source and then sintered in the present application. Namely, the carbon coating is completed by a wet coating method, which is superior to a solid phase coating method, has good ion diffusivity, can uniformly coat the surface of the precursor, and improves the coating uniformity.
The sintering temperature should be limited, and as a preferred aspect of the present application, in step S2, the sintering is a stepwise temperature-increasing sintering, including the steps of: firstly sintering at 350-370 ℃ for 2.5-3.5h, and then sintering at 650-750 ℃ for 6-8h.
Finally, the application also provides application of the lithium iron phosphate composite material in a battery anode material. The lithium iron phosphate composite material is applied to a battery anode material, and can obviously improve the electrochemical performance of a battery.
The application has the beneficial effects that:
1. the application provides a lithium iron phosphate composite material, which belongs to a double-molecular-layer coating material, wherein doping metal is doped on the surface of lithium iron phosphate and then carbon coating is carried out, so that on one hand, a hybridization conductive layer is established on the surface of active particles, and the transfer efficiency of lithium ions/electrons is improved; on the other hand, the doped metal effectively improves the connection tightness between the lithium iron phosphate and the carbon, thereby improving the conductivity and the cycling stability of the composite material.
2. The application provides a preparation method of a lithium iron phosphate composite material, which takes a precursor of doped metal oxide as a doped metal source to sequentially obtain the doped metal oxide and the doped metal, so that the ion doping uniformity and the bonding compactness of the doped metal and carbon can be improved.
3. In an alternative embodiment, the precursor is obtained by a hot solvent method, so that the element doping process is stable and the doping effect is uniform.
4. In an alternative embodiment, the nano-cellulose with small particle size is used as the carbon coating material, so that the carbon coating material has the effects of compact coating degree, uniform coating and improvement of tap density and electrochemical performance of the material.
Drawings
FIG. 1 is a schematic structural diagram of a lithium iron phosphate composite;
FIG. 2 is a flow chart of the preparation of a lithium iron phosphate composite material of example 1;
fig. 3 is an SEM image of the lithium iron phosphate composite material prepared in example 1.
Detailed Description
The following is a specific embodiment of the present application, and the technical solution of the present application is further described with reference to the accompanying drawings, but the present application is not limited to these examples.
Example 1
The lithium iron phosphate composite material sequentially comprises a lithium iron phosphate inner core, a titanium surface doping layer and a carbon coating layer from inside to outside as shown in fig. 1.
The lithium iron phosphate composite material is prepared by the following steps: the preparation flow chart is shown in fig. 2.
S1, mixing the following components: fe: p: the mole of Ti atoms is 2:1:1:0.25, wherein the molar ratio of the reducing agent to the iron source is 1.02:1, proportioning; firstly, adding lithium carbonate serving as a lithium source, ferric sulfite serving as an iron source, monoammonium phosphate serving as a phosphorus source, tetrabutyl titanate serving as a titanium source and nanocellulose serving as a reducing agent into a ball milling tank containing a mixed solution of ethylene glycol and deionized water according to the proportion, hydrolyzing at 50 ℃, and ball milling at the rotating speed of 400r/min; ball milling time is 4.5 hours, and a precursor is obtained.
S2, adding nanofiber crystals (with the diameter of 5-70nm and the length of 100-250 nm) into ethanol, water and mixed solution to be uniformly dispersed, and thus obtaining the nano cellulose suspension.
The ball-milled precursor is alternately washed by ethanol and deionized water and then added into a nanocellulose suspension, wherein the mass ratio of nanocellulose to precursor is 5:100, stirring uniformly. Then placing the mixture into an air box at 80 ℃ for drying; grinding and sintering the dried raw materials in a nitrogen atmosphere, wherein the sintering process is divided into gradual heating sintering; firstly sintering for 3 hours at 360 ℃ and then sintering for 7 hours at 700 ℃ to obtain a final lithium iron phosphate sample.
An SEM image of the prepared lithium iron phosphate composite material is shown in fig. 3.
Example 2
This embodiment is substantially the same as embodiment 1, except that: the method comprises the following steps of: fe: p: the mole of Ti atoms is 2:1:1: and 0.28 proportion.
Example 3
This embodiment is substantially the same as embodiment 1, except that: the method comprises the following steps of: fe: p: the mole of Ti atoms is 2:1:1: and 0.30 proportion.
Example 4
This embodiment is substantially the same as embodiment 1, except that: the titanium source is replaced with a vanadium source.
The lithium iron phosphate composite material sequentially comprises a lithium iron phosphate inner core, a vanadium surface doping layer and a carbon coating layer from inside to outside.
The lithium iron phosphate composite material is prepared by the following steps:
s1, mixing the following components: fe: p: al atom mole is 2:1:1:0.25, wherein the molar ratio of the reducing agent to the iron source is 1.02:1, proportioning; firstly, adding lithium carbonate serving as a lithium source, ferric sulfite serving as an iron source, monoammonium phosphate serving as a phosphorus source, ammonium metavanadate serving as a vanadium source and nanocellulose serving as a reducing agent into a ball milling tank containing a mixed solution of ethylene glycol and deionized water according to the proportion, hydrolyzing at 50 ℃, and ball milling at the rotating speed of 400r/min; ball milling time is 4.5 hours, and a precursor is obtained.
S2, adding nanofiber crystals (with the diameter of 5-70nm and the length of 100-250 nm) into ethanol, water and mixed solution to be uniformly dispersed, and thus obtaining the nano cellulose suspension.
The ball-milled precursor is alternately washed by ethanol and deionized water and then added into a nanocellulose suspension, wherein the mass ratio of nanocellulose to precursor is 5:100, stirring uniformly. Then placing the mixture into an air box at 80 ℃ for drying; grinding and sintering the dried raw materials in a nitrogen atmosphere, wherein the sintering process is divided into gradual heating sintering; firstly sintering for 3 hours at 360 ℃ and then sintering for 7 hours at 700 ℃ to obtain a final lithium iron phosphate sample.
Example 5
This embodiment is substantially the same as embodiment 1, except that: the nanofiber crystals (diameter 5-70nm, length 100-250 nm) were replaced with cellulose microfibrils (diameter 5-60nm, length on the order of microns).
Example 6
This embodiment is substantially the same as embodiment 1, except that: and sintering to obtain the titanium dioxide.
The composite material sequentially comprises a lithium iron phosphate core, a titanium surface doping layer and a carbon coating layer from inside to outside.
The lithium iron phosphate composite material is prepared by the following steps:
s1, mixing the following components: fe: p: the mole of Ti atoms is 2:1:1:0.25, wherein the molar ratio of the reducing agent to the iron source is 1.02:1, proportioning; firstly, adding lithium carbonate serving as a lithium source, ferrous sulfite serving as an iron source, monoammonium phosphate serving as a phosphorus source, tetrabutyl titanate serving as a titanium source and nanocellulose serving as a reducing agent into a ball milling tank containing absolute ethyl alcohol according to the proportion, and performing ball milling at the rotating speed of 400r/min for 4.5 hours. Then placing the mixture in a drying oven for heat preservation and drying at 70 ℃, then heating to 500 ℃ at a speed of 5 ℃/min, heat preservation for 1 hour, and cooling to room temperature along with the furnace to obtain the precursor.
S2, adding nanofiber crystals (with the diameter of 5-70nm and the length of 100-250 nm) into ethanol, water and mixed solution to be uniformly dispersed, and thus obtaining the nano cellulose suspension.
Alternately washing the precursor with ethanol and deionized water, and then adding the precursor into a nanocellulose suspension, wherein the mass ratio of nanocellulose to the precursor is 5:100, stirring uniformly. Then placing the mixture into an air box at 80 ℃ for drying; grinding and sintering the dried raw materials in a nitrogen atmosphere, wherein the sintering process is divided into gradual heating sintering; firstly sintering for 3 hours at 360 ℃ and then sintering for 7 hours at 700 ℃ to obtain a final lithium iron phosphate sample.
Example 7
This embodiment is substantially the same as embodiment 1, except that: the carbon source is coated by a solid phase.
The composite material sequentially comprises a lithium iron phosphate core, a titanium surface doping layer and a carbon coating layer from inside to outside.
The lithium iron phosphate composite material is prepared by the following steps:
s1, mixing the following components: fe: p: the mole of Ti atoms is 2:1:1:0.25, wherein the molar ratio of the reducing agent to the iron source is 1.02:1, proportioning; firstly, adding lithium carbonate serving as a lithium source, ferric sulfite serving as an iron source, monoammonium phosphate serving as a phosphorus source, tetrabutyl titanate serving as a titanium source and nanocellulose serving as a reducing agent into a ball milling tank containing a mixed solution of ethylene glycol and deionized water according to the proportion, hydrolyzing at 50 ℃, and ball milling at the rotating speed of 400r/min; ball milling time is 4.5 hours, and a precursor is obtained.
S2, alternately washing the ball-milled precursor with ethanol and deionized water, and then mixing with nanofiber crystals (with the diameter of 5-70nm and the length of 100-250 nm), wherein the mass ratio of the nanocellulose to the precursor is 5:100, stirring uniformly. Then placing the mixture into an air box at 80 ℃ for drying; grinding and sintering the dried raw materials in a nitrogen atmosphere, wherein the sintering process is divided into gradual heating sintering; firstly sintering for 3 hours at 360 ℃ and then sintering for 7 hours at 700 ℃ to obtain a final lithium iron phosphate sample.
Example 8
This embodiment is substantially the same as embodiment 1, except that: sintering by adopting one-step heating.
The composite material sequentially comprises a lithium iron phosphate core, a titanium surface doping layer and a carbon coating layer from inside to outside.
The lithium iron phosphate composite material is prepared by the following steps:
s1, mixing the following components: fe: p: the mole of Ti atoms is 2:1:1:0.25, wherein the molar ratio of the reducing agent to the iron source is 1.02:1, proportioning; firstly, adding lithium carbonate serving as a lithium source, ferric sulfite serving as an iron source, monoammonium phosphate serving as a phosphorus source, tetrabutyl titanate serving as a titanium source and nanocellulose serving as a reducing agent into a ball milling tank containing a mixed solution of ethylene glycol and deionized water according to the proportion, hydrolyzing at 50 ℃, and ball milling at the rotating speed of 400r/min; ball milling time is 4.5 hours, and a precursor is obtained.
S2, adding nanofiber crystals (with the diameter of 5-70nm and the length of 100-250 nm) into ethanol, water and mixed solution to be uniformly dispersed, and thus obtaining the nano cellulose suspension.
The ball-milled precursor is alternately washed by ethanol and deionized water and then added into a nanocellulose suspension, wherein the mass ratio of nanocellulose to precursor is 5:100, stirring uniformly. Then placing the mixture into an air box at 80 ℃ for drying; grinding and sintering the dried raw materials in a nitrogen atmosphere, wherein the sintering process is that the raw materials are sintered for 10 hours at 700 ℃, and a final lithium iron phosphate sample is prepared.
Comparative example 1
This comparative example is substantially the same as example 1, except that: no titanium source was added.
A lithium iron phosphate composite material sequentially comprises a lithium iron phosphate inner core and a carbon coating layer from inside to outside.
The lithium iron phosphate composite material is prepared by the following steps:
s1, mixing the following components: fe: the mole of P atoms is 2:1:1, the molar ratio of the reducing agent to the iron source is 1.02:1, proportioning; firstly, adding lithium carbonate serving as a lithium source, ferric sulfite serving as an iron source, monoammonium phosphate serving as a phosphorus source and nanocellulose serving as a reducing agent into a ball milling tank containing a mixed solution of ethylene glycol and deionized water according to the proportion, hydrolyzing at 50 ℃, and ball milling at the rotating speed of 400r/min; ball milling time is 4.5 hours, and a precursor is obtained.
S2, adding nanofiber crystals (with the diameter of 5-70nm and the length of 100-250 nm) into ethanol, water and mixed solution to be uniformly dispersed, and thus obtaining the nano cellulose suspension.
The ball-milled precursor is alternately washed by ethanol and deionized water and then added into a nanocellulose suspension, wherein the mass ratio of nanocellulose to precursor is 5:100, stirring uniformly. Then placing the mixture into an air box at 80 ℃ for drying; grinding and sintering the dried raw materials in a nitrogen atmosphere, wherein the sintering process is divided into gradual heating sintering; firstly sintering for 3 hours at 360 ℃ and then sintering for 7 hours at 700 ℃ to obtain a final lithium iron phosphate sample.
Comparative example 2
This comparative example is substantially the same as example 1, except that: bulk phase doped with titanium.
The composite material sequentially comprises a titanium-doped lithium iron phosphate core and a carbon coating layer from inside to outside.
The lithium iron phosphate composite material is prepared by the following steps:
s1, mixing the following components: fe: p: the mole of Ti atoms is 2:1:1:0.25, wherein the molar ratio of the reducing agent to the iron source is 1.02:1, proportioning; firstly, adding lithium carbonate serving as a lithium source, ferrous sulfite serving as an iron source, monoammonium phosphate serving as a phosphorus source, titanium dioxide serving as a titanium source and nanocellulose serving as a reducing agent into a ball milling tank containing absolute ethyl alcohol according to the proportion for ball milling at the rotating speed of 400r/min for 4.5 hours; then drying in an oven at 80 ℃ under nitrogen atmosphere until the absolute ethanol is completely volatilized, thoroughly grinding again to obtain a dried mixture, calcining the dried mixture at 200 ℃ under nitrogen atmosphere for 5 hours, and then cooling to room temperature to obtain a precursor.
S2, adding nanofiber crystals (with the diameter of 5-70nm and the length of 100-250 nm) into ethanol, water and mixed solution to be uniformly dispersed, and thus obtaining the nano cellulose suspension.
The ball-milled precursor is alternately washed by ethanol and deionized water and then added into a nanocellulose suspension, wherein the mass ratio of nanocellulose to precursor is 5:100, stirring uniformly. Then placing the mixture into an air box at 80 ℃ for drying; grinding and sintering the dried raw materials in a nitrogen atmosphere, wherein the sintering process is divided into gradual heating sintering; firstly sintering for 3 hours at 360 ℃ and then sintering for 7 hours at 700 ℃ to obtain a final lithium iron phosphate sample.
Comparative example 3
This comparative example is substantially the same as example 1, except that: glucose (greater than 100 μm) was used as a carbon source.
Performance detection
The composite materials prepared in examples and comparative examples were used as positive electrode materials in a ratio of 96:2:2, mixing the mixture with Surpe-P, PVDF according to the mass ratio, preparing slurry by using NMP as a solvent, coating the slurry on a metal aluminum foil to prepare a positive electrode, and finally cutting the positive electrode into a round pole piece with the diameter of 12mm by using a punch as a working electrode; in a purged glove box filled with Ar (O 2 Content of H less than 0.1ppm 2 O content is less than 0.1 ppm), a lithium sheet is used as a negative electrode, a diaphragm is a polypropylene microporous membrane, electrolyte is 1mol/L lithium hexafluorophosphate (LiPF 6) (EC: DEC=1:1), a CR2032 type button cell is prepared according to a certain assembly process, and standing is carried out for 24 hours after completion to fully infiltrate the electrolyte and an electrode material. Electrochemical performance measurements were carried out at room temperature (25 ℃ C.+ -. 1) at a voltage range of 2.0-3.7V, and the results are shown in Table 1 below.
Table 1.
As can be seen from table 1, comparing example 1 with comparative examples 1 and 2, in this example, the electrochemical properties of the materials are greatly improved compared to the surface doped titanium without doping titanium and the conventional bulk doped titanium. The applicant speculates that the reason is that: the intermediate doped titanium improves the connection tightness between the lithium iron phosphate and the carbon.
As can be seen from the comparison of example 1, example 5 and comparative example 3, the particle size of the carbon-coated material has an influence on the final electrochemical properties of the composite material, and the smaller the particle size, the better the electrochemical properties. The applicant speculates that the reason is that: the coating performance of the carbon material with smaller particle size is more uniform, and gaps among particles can be filled better, so that the tap density and electrochemical performance of the material are improved.
As can be seen from a comparison of example 1, example 6 and example 7, the thermal solvent method at the time of surface doping has better electrochemical properties than the composite material obtained by sintering, and the wet coating method at the time of carbon coating has better electrochemical properties than the composite material obtained by solid phase coating. The applicant speculates that the reason is that: in the wet doping and coating, the element doping and coating process is stable and uniform, and the doping uniformity and compactness of the doped metal on the lithium iron phosphate are improved, and the doping uniformity and compactness of the carbon coating on the metal doping layer and the lithium iron phosphate are improved.
As can be seen from the comparison of example 1 and example 8, the stepwise temperature-rising sintering has better electrochemical properties than the one-step temperature-rising sintering. The applicant speculates that the reason is that: the titanium dioxide is fully reduced in the step sintering, and then the carbon is sintered and combined, so that the purity of the titanium and the compactness of the carbon coating are improved.
The specific embodiments described herein are offered by way of example only to illustrate the spirit of the application. Those skilled in the art may make various modifications or additions to the described embodiments or substitutions thereof without departing from the spirit of the application or exceeding the scope of the application as defined in the accompanying claims.
Claims (10)
1. A lithium iron phosphate composite material, characterized in that: the composite material sequentially comprises a lithium iron phosphate inner core, a metal surface doping layer and a carbon coating layer from inside to outside.
2. A lithium iron phosphate composite according to claim 1, wherein: the doping metal used for the metal surface doping layer comprises one or two of titanium and vanadium.
3. A lithium iron phosphate composite according to claim 1, wherein: the particle size of the carbon used for the carbon coating layer is not more than 1000nm.
4. A method of preparing the lithium iron phosphate composite of any one of claims 1-3, characterized by: the method comprises the following steps:
s1, mixing a lithium source, an iron source, a phosphorus source, a doped metal source and a reducing agent, and operating under the condition of converting the doped metal source into doped metal oxide to obtain a precursor;
s2, mixing the precursor with a carbon source, and sintering to obtain the lithium iron phosphate composite material.
5. The method for preparing the lithium iron phosphate composite material according to claim 4, wherein the method comprises the following steps: in the step S1, in the lithium source, the iron source, the phosphorus source and the doped metal source, the molar ratio of the elements lithium, iron, phosphorus and doped metal is (1.5-3): 1:1: (0.25-0.3).
6. The method for preparing the lithium iron phosphate composite material according to claim 4, wherein the method comprises the following steps: in step S1, the conditions include heat treatment.
7. The method for preparing the lithium iron phosphate composite material according to claim 6, wherein the method comprises the following steps: the heat treatment is a solvothermal treatment in which: the solvent comprises mixed solution of alcohol solvent and water, and the treatment temperature is 40-60 ℃.
8. The method for preparing the lithium iron phosphate composite material according to claim 4, wherein the method comprises the following steps: in step S2, the precursor is mixed with the alcohol solution of the carbon source, and then dried and sintered.
9. The method for preparing the lithium iron phosphate composite material according to claim 4, wherein the method comprises the following steps: in step S2, the sintering is a step-by-step temperature-rising sintering, which includes the following steps: firstly sintering at 350-370 ℃ for 2.5-3.5h, and then sintering at 650-750 ℃ for 6-8h.
10. Use of a lithium iron phosphate composite material according to any one of claims 1-3 in a battery positive electrode material.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311172263.6A CN117096313A (en) | 2023-09-12 | 2023-09-12 | Lithium iron phosphate composite material and preparation method and application thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311172263.6A CN117096313A (en) | 2023-09-12 | 2023-09-12 | Lithium iron phosphate composite material and preparation method and application thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117096313A true CN117096313A (en) | 2023-11-21 |
Family
ID=88779086
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311172263.6A Pending CN117096313A (en) | 2023-09-12 | 2023-09-12 | Lithium iron phosphate composite material and preparation method and application thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117096313A (en) |
-
2023
- 2023-09-12 CN CN202311172263.6A patent/CN117096313A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP7027387B2 (en) | Titanium dope niobate and batteries | |
| KR102562685B1 (en) | Nickel-based active material precursor for lithium secondary battery.preparing method thereof, nickel-based active material for lithium secondary battery formed thereof, and lithium secondary battery comprising positive electrode including the nickel-based active material | |
| WO2018032569A1 (en) | Limn1-xfexpo4 cathode material having core-shell structure, preparation method therefor, and lithium-ion battery | |
| JP7419381B2 (en) | Positive electrode material, its manufacturing method, and lithium secondary battery | |
| KR100946387B1 (en) | Olivine type positive active material precursor for lithium battery, olivine type positive active material for lithium battery, method for preparing the same, and lithium battery comprising the same | |
| CN108448113B (en) | Preparation method of doped modified lithium iron phosphate positive-grade material | |
| CN115557537A (en) | MnS nanodot material, ternary sodium electric precursor, anode material and preparation method | |
| KR20160090580A (en) | Positive electrode active material, preparing method thereof, and lithium secondary battery employing positive electrode comprising the positive electrode active material | |
| Han et al. | The effects of copper and titanium co-substitution on LiNi 0.6 Co 0.15 Mn 0.25 O 2 for lithium ion batteries | |
| CN115832257A (en) | Lithium manganese iron phosphate positive electrode material, preparation method and application thereof | |
| Lei et al. | Preparing enhanced electrochemical performances Fe2O3-coated LiNi1/3Co1/3Mn1/3O2 cathode materials by thermal decomposition of iron citrate | |
| KR101614015B1 (en) | Cathode active material for lithium rechargeable batteries and manufacturing method of the same | |
| CN110970601A (en) | Double-gradient coated high-nickel ternary cathode material and preparation method thereof | |
| CN116177556B (en) | Sodium-electricity positive electrode material, precursor thereof, preparation method and application | |
| CN106505196B (en) | A kind of application of the vanadium phosphate cathode material in lithium ion battery for adulterating bismuth | |
| CN116101994A (en) | Heteropolyacid modified layered oxide sodium battery positive electrode material and preparation method thereof | |
| CN110797519A (en) | Lithium ion battery positive electrode material, preparation method and lithium ion battery | |
| CN116130621A (en) | Polyanionic sodium ion battery positive electrode material, preparation and application thereof | |
| Zhang et al. | Facile Fabrication Hierarchical Pore Structure Li1. 2Mn0. 54Ni0. 13Co0. 13-xSrxO2 Nanofiber for High-Performance Cathode Materials | |
| CN117096313A (en) | Lithium iron phosphate composite material and preparation method and application thereof | |
| US8889297B2 (en) | Nanocomposite cathode active material for lithium secondary batteries, method for preparing the same and lithium secondary batteries comprising the same | |
| KR20190057530A (en) | Positive electrode active material for lithium secondary battery and method for preparing the same | |
| CN114566647A (en) | Calcium phosphate coated high-nickel ternary cathode material and preparation method and application thereof | |
| JP6966637B2 (en) | Positive electrode material for lithium secondary batteries and its manufacturing method | |
| JP7133690B1 (en) | Lithium titanate/titanium niobium oxide core-shell composite material and method for producing the same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |