CN113772650A - Preparation method and application of lithium iron phosphate - Google Patents
Preparation method and application of lithium iron phosphate Download PDFInfo
- Publication number
- CN113772650A CN113772650A CN202111107692.6A CN202111107692A CN113772650A CN 113772650 A CN113772650 A CN 113772650A CN 202111107692 A CN202111107692 A CN 202111107692A CN 113772650 A CN113772650 A CN 113772650A
- Authority
- CN
- China
- Prior art keywords
- iron phosphate
- phosphate
- lithium iron
- solution
- mixed slurry
- 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.)
- Granted
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 99
- 238000002360 preparation method Methods 0.000 title claims abstract description 31
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 59
- 238000000034 method Methods 0.000 claims abstract description 51
- 239000011268 mixed slurry Substances 0.000 claims abstract description 49
- 229910019142 PO4 Inorganic materials 0.000 claims abstract description 47
- 239000000463 material Substances 0.000 claims abstract description 47
- WBJZTOZJJYAKHQ-UHFFFAOYSA-K iron(3+) phosphate Chemical compound [Fe+3].[O-]P([O-])([O-])=O WBJZTOZJJYAKHQ-UHFFFAOYSA-K 0.000 claims abstract description 36
- 239000002245 particle Substances 0.000 claims abstract description 28
- 239000010452 phosphate Substances 0.000 claims abstract description 28
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims abstract description 27
- 238000003786 synthesis reaction Methods 0.000 claims abstract description 27
- 235000003891 ferrous sulphate Nutrition 0.000 claims abstract description 24
- 239000011790 ferrous sulphate Substances 0.000 claims abstract description 24
- 229910000359 iron(II) sulfate Inorganic materials 0.000 claims abstract description 24
- 229910052742 iron Inorganic materials 0.000 claims abstract description 23
- 229910000398 iron phosphate Inorganic materials 0.000 claims abstract description 23
- 238000005406 washing Methods 0.000 claims abstract description 22
- 238000001354 calcination Methods 0.000 claims abstract description 20
- 238000001035 drying Methods 0.000 claims abstract description 20
- 239000000203 mixture Substances 0.000 claims abstract description 20
- 239000011812 mixed powder Substances 0.000 claims abstract description 19
- 239000012065 filter cake Substances 0.000 claims abstract description 18
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 claims abstract description 16
- 229910001416 lithium ion Inorganic materials 0.000 claims abstract description 16
- 238000002156 mixing Methods 0.000 claims abstract description 16
- 239000005955 Ferric phosphate Substances 0.000 claims abstract description 14
- 229940032958 ferric phosphate Drugs 0.000 claims abstract description 14
- 229910000399 iron(III) phosphate Inorganic materials 0.000 claims abstract description 14
- 230000032683 aging Effects 0.000 claims abstract description 12
- 238000000227 grinding Methods 0.000 claims abstract description 12
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims abstract description 11
- NDLPOXTZKUMGOV-UHFFFAOYSA-N oxo(oxoferriooxy)iron hydrate Chemical compound O.O=[Fe]O[Fe]=O NDLPOXTZKUMGOV-UHFFFAOYSA-N 0.000 claims abstract description 11
- 229910001386 lithium phosphate Inorganic materials 0.000 claims abstract description 10
- TWQULNDIKKJZPH-UHFFFAOYSA-K trilithium;phosphate Chemical compound [Li+].[Li+].[Li+].[O-]P([O-])([O-])=O TWQULNDIKKJZPH-UHFFFAOYSA-K 0.000 claims abstract description 10
- 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 abstract description 9
- 239000008103 glucose Substances 0.000 claims abstract description 9
- 238000012216 screening Methods 0.000 claims abstract description 8
- 239000007788 liquid Substances 0.000 claims abstract description 4
- 238000000926 separation method Methods 0.000 claims abstract description 3
- 238000006243 chemical reaction Methods 0.000 claims description 28
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 21
- 229910052698 phosphorus Inorganic materials 0.000 claims description 17
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 16
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims description 16
- 239000011574 phosphorus Substances 0.000 claims description 16
- 238000001694 spray drying Methods 0.000 claims description 16
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 13
- 239000006227 byproduct Substances 0.000 claims description 13
- 238000001914 filtration Methods 0.000 claims description 12
- SURQXAFEQWPFPV-UHFFFAOYSA-L iron(2+) sulfate heptahydrate Chemical compound O.O.O.O.O.O.O.[Fe+2].[O-]S([O-])(=O)=O SURQXAFEQWPFPV-UHFFFAOYSA-L 0.000 claims description 12
- 239000013078 crystal Substances 0.000 claims description 9
- 230000001681 protective effect Effects 0.000 claims description 9
- MNNHAPBLZZVQHP-UHFFFAOYSA-N diammonium hydrogen phosphate Chemical compound [NH4+].[NH4+].OP([O-])([O-])=O MNNHAPBLZZVQHP-UHFFFAOYSA-N 0.000 claims description 8
- 229910052757 nitrogen Inorganic materials 0.000 claims description 8
- 238000004519 manufacturing process Methods 0.000 claims description 7
- 238000011946 reduction process Methods 0.000 claims description 7
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 6
- 238000004321 preservation Methods 0.000 claims description 6
- 239000004254 Ammonium phosphate Substances 0.000 claims description 5
- LFVGISIMTYGQHF-UHFFFAOYSA-N ammonium dihydrogen phosphate Chemical compound [NH4+].OP(O)([O-])=O LFVGISIMTYGQHF-UHFFFAOYSA-N 0.000 claims description 5
- 229910000387 ammonium dihydrogen phosphate Inorganic materials 0.000 claims description 5
- 229910000148 ammonium phosphate Inorganic materials 0.000 claims description 5
- 235000019289 ammonium phosphates Nutrition 0.000 claims description 5
- 235000019837 monoammonium phosphate Nutrition 0.000 claims description 5
- 239000005696 Diammonium phosphate Substances 0.000 claims description 3
- 229910001209 Low-carbon steel Inorganic materials 0.000 claims description 3
- 229910052786 argon Inorganic materials 0.000 claims description 3
- 229910000388 diammonium phosphate Inorganic materials 0.000 claims description 3
- 235000019838 diammonium phosphate Nutrition 0.000 claims description 3
- 229910052734 helium Inorganic materials 0.000 claims description 2
- 239000001307 helium Substances 0.000 claims description 2
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 claims description 2
- 239000004408 titanium dioxide Substances 0.000 claims description 2
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 abstract description 22
- 230000015572 biosynthetic process Effects 0.000 abstract description 16
- 239000010405 anode material Substances 0.000 abstract description 13
- 238000009826 distribution Methods 0.000 abstract description 8
- 229910052744 lithium Inorganic materials 0.000 abstract description 5
- 238000005457 optimization Methods 0.000 abstract 1
- 238000004886 process control Methods 0.000 abstract 1
- 238000005056 compaction Methods 0.000 description 12
- 238000001514 detection method Methods 0.000 description 11
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 10
- 235000010215 titanium dioxide Nutrition 0.000 description 10
- 230000000052 comparative effect Effects 0.000 description 8
- 238000004806 packaging method and process Methods 0.000 description 7
- 238000001878 scanning electron micrograph Methods 0.000 description 7
- 239000000843 powder Substances 0.000 description 6
- 238000003756 stirring Methods 0.000 description 6
- 239000002351 wastewater Substances 0.000 description 6
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 5
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 5
- 235000011114 ammonium hydroxide Nutrition 0.000 description 5
- 229910052799 carbon Inorganic materials 0.000 description 5
- 238000001704 evaporation Methods 0.000 description 5
- 230000008020 evaporation Effects 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 4
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 4
- 229910000155 iron(II) phosphate Inorganic materials 0.000 description 4
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 description 4
- 229910052808 lithium carbonate Inorganic materials 0.000 description 4
- 239000007800 oxidant agent Substances 0.000 description 4
- 230000001590 oxidative effect Effects 0.000 description 4
- 230000001698 pyrogenic effect Effects 0.000 description 4
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 description 3
- 229910052921 ammonium sulfate Inorganic materials 0.000 description 3
- 229940116007 ferrous phosphate Drugs 0.000 description 3
- 239000003337 fertilizer Substances 0.000 description 3
- 238000003837 high-temperature calcination Methods 0.000 description 3
- 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 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 235000011130 ammonium sulphate Nutrition 0.000 description 2
- 239000010406 cathode material Substances 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 238000004146 energy storage Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 238000003912 environmental pollution Methods 0.000 description 2
- -1 iron ions Chemical class 0.000 description 2
- 239000011164 primary particle Substances 0.000 description 2
- 238000001223 reverse osmosis Methods 0.000 description 2
- 239000013589 supplement Substances 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 229910010710 LiFePO Inorganic materials 0.000 description 1
- 238000000498 ball milling 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
- 238000004364 calculation method Methods 0.000 description 1
- 238000003763 carbonization Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 238000009831 deintercalation Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000000706 filtrate Substances 0.000 description 1
- 239000013505 freshwater Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- YOBAEOGBNPPUQV-UHFFFAOYSA-N iron;trihydrate Chemical compound O.O.O.[Fe].[Fe] YOBAEOGBNPPUQV-UHFFFAOYSA-N 0.000 description 1
- 239000002105 nanoparticle Substances 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 150000003013 phosphoric acid derivatives Chemical class 0.000 description 1
- 239000007774 positive electrode material Substances 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 239000002243 precursor Substances 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 239000010865 sewage Substances 0.000 description 1
- 238000007873 sieving Methods 0.000 description 1
- 238000003746 solid phase reaction Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
- 238000004065 wastewater treatment Methods 0.000 description 1
Images
Classifications
-
- 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
-
- 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
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/60—Particles characterised by their size
- C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/60—Particles characterised by their size
- C01P2004/62—Submicrometer sized, i.e. from 0.1-1 micrometer
-
- 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
-
- 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
-
- 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
- C01P2006/80—Compositional purity
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Crystallography & Structural Chemistry (AREA)
- Materials Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
The invention relates to the technical field of preparation of lithium ion battery anode materials, in particular to a preparation method and application of lithium iron phosphate. The preparation method comprises the following steps: mixing a ferrous sulfate solution and a phosphate solution, carrying out a synthesis reaction, then aging the solution, carrying out solid-liquid separation on the aged solution, washing a filter cake, drying, calcining, crushing, screening and removing iron to obtain a mixture of anhydrous iron phosphate and ferric oxide; mixing the mixture with Li3PO4、H3PO4Sequentially adding the mixed slurry into a glucose solution to obtain mixed slurry, grinding the mixed slurry to obtain nanoscale mixed slurry, and drying the nanoscale mixed slurry to obtain a mixed powder material; and roasting the mixed powder material at the temperature of 700 plus 800 ℃, and crushing to obtain the lithium iron phosphate. The method realizes the anhydrous ferric phosphate in an inorganic systemThe anhydrous ferric phosphate obtained by one-step synthesis has good dispersibility and uniform particle size distribution, and is convenient for rear-end ferric phosphate lithium process control and performance parameter optimization.
Description
Technical Field
The invention relates to the technical field of preparation of lithium ion battery anode materials, in particular to a preparation method and application of lithium iron phosphate.
Background
With the increasing exhaustion of petroleum resources, the development of electric vehicles is imperative. At present, the most critical technology of electric vehicles is to develop a secondary battery that is inexpensive, safe, and environmentally friendly. Lithium ion batteries are known as the best candidates for power batteries of electric vehicles due to their high voltage, high specific energy and high power. For lithium ion batteries, the positive electrode material is a key factor in determining electrochemical performance, safety performance, energy density, and price cost. The first report in 1997 of olivine-structured LiFePO by Goodenough et al4The reversible lithium intercalation-deintercalation characteristics of (1). The lithium ion battery anode material has the advantages of good safety performance, long cycle life, wide raw material source, environmental friendliness and the like, and is always a hotspot for research and development of lithium ion battery anode materials.
The current mainstream process of lithium iron phosphate takes anhydrous iron phosphate as a precursor, and the synthesis of the lithium iron phosphate by adopting the anhydrous iron phosphate has the following advantages: 1. the operation process is simple, and the industrialization maturity is high; 2. the obtained lithium iron phosphate has high capacity and high compaction density; 3. the safety performance is good; 4 the cycle life is long.
At present, the conventional lithium iron phosphate is synthesized by generally adopting ferrous salt, phosphate and an oxidant to obtain ferric phosphate dihydrate, then drying and calcining at high temperature to obtain anhydrous ferric phosphate, then mixing the anhydrous ferric phosphate, lithium carbonate, glucose and pure water according to a certain proportion, and obtaining the battery-grade lithium iron phosphate by ball sanding, spray drying, high-temperature calcination (nitrogen protection), air flow crushing, iron removal and packaging. The process has high maturity and is generally used. However, it has the following disadvantages:
firstly, the environmental protection pressure is large in the production process of the anhydrous iron phosphate, the wastewater treatment cost is high, according to statistics, nearly seventy tons of wastewater are generated by each ton of iron phosphate, and the wastewater contains some pollution factors such as sulfate radicals, phosphate radicals, ammonium radicals and iron ions, the treatment capacity is large, and the treatment cost is high.
Secondly, the production process of the anhydrous ferric phosphate is long in process flow, the process flow comprises the processes of synthesis of the dihydrate ferric phosphate, washing, drying, high-temperature calcination and dehydration and the like, the equipment investment is large, the labor cost and the energy consumption cost are high, the cost of the final anhydrous ferric phosphate product is high, and the cost of the lithium iron phosphate is high.
Thirdly, lithium carbonate is expensive in production of lithium iron phosphate, energy consumption is high in the production process, and cost is high.
In view of the above, the present invention is particularly proposed.
Disclosure of Invention
The invention aims to provide a preparation method of lithium iron phosphate, which is simple and short in process, realizes a one-step synthesis process of anhydrous iron phosphate in an inorganic system, does not use steam and an oxidant in the process, simplifies the process flow, produces less wastewater, and has low cost, and the obtained anhydrous iron phosphate has good dispersibility and uniform particle size distribution. Meanwhile, in the pyrogenic synthesis stage of the lithium iron phosphate material, low-cost Li is adopted3PO4And H3PO4Commonly used and relatively expensive Li as substitute material2CO3The lithium ion battery anode material lithium iron phosphate prepared by the method has lower cost, and the comprehensive performances of the material such as compaction density, specific capacity and the like are ensured.
The second purpose of the present invention is to provide the use of the lithium iron phosphate prepared by the above method for preparing lithium iron phosphate in the preparation of a lithium ion battery anode, which simplifies the process flow, saves the preparation cost, and has high compacted density and specific capacity of the prepared lithium ion battery anode.
In order to achieve the above purpose of the present invention, the following technical solutions are adopted:
a preparation method of lithium iron phosphate comprises the following steps:
(a) mixing a ferrous sulfate solution and a phosphate solution and carrying out a synthesis reaction, aging the solution after the synthesis reaction, carrying out solid-liquid separation on the aged solution, washing a filter cake, drying, calcining, crushing, screening and removing iron to obtain a mixture of anhydrous iron phosphate and ferric oxide;
(b) the mixture obtained in step (a) and Li3PO4、H3PO4Adding glucose in sequenceObtaining mixed slurry in the solution, grinding the mixed slurry to obtain nanoscale mixed slurry, and drying the nanoscale mixed slurry to obtain a mixed powder material;
(c) and (c) roasting the mixed powder material obtained in the step (b) at the temperature of 700 ℃ and 800 ℃, and crushing to obtain the lithium iron phosphate.
The preparation method of the lithium iron phosphate provided by the invention is simple and feasible, has short process, realizes the one-step synthesis process of the anhydrous iron phosphate in an inorganic system, does not use steam and an oxidant in the process, simplifies the process flow, has small wastewater generation amount and low cost, and the obtained anhydrous iron phosphate has good dispersibility and uniform particle size distribution. Meanwhile, in the pyrogenic synthesis stage of the lithium iron phosphate material, low-cost Li is adopted3PO4And H3PO4Commonly used and relatively expensive Li as substitute material2CO3The lithium ion battery anode material lithium iron phosphate prepared by the method has lower cost, and the comprehensive performances of the material such as compaction density, specific capacity and the like are ensured.
The preparation method involves the following main chemical reactions:
3FeSO4+2NH4H2PO4+4NH3H2O+4H2O→Fe3(PO4)2·8H2O↓+3(NH4)2SO4；
4Fe3(PO4)2·8H2O+3O2→8FePO4+2Fe2O3+32H2O；
8FePO4+2Fe2O3+3C+4Li3PO4→12LiFePO4+3CO2。
the method comprises the steps of synthesizing ferrous phosphate in the first step, controlling the concentration, temperature, pH and mixing speed of a ferrous sulfate solution and a phosphate solution, controlling the stirring speed, temperature and time after the ferrous sulfate solution and the phosphate solution enter a reaction kettle, and thus obtaining pure ferrous phosphate precipitate.
And washing the obtained ferrous phosphate, and then drying, calcining, screening and removing iron to obtain a battery-grade anhydrous ferric phosphate and ferric oxide mixture with good dispersibility, high purity and uniform particle size distribution. Wherein, the concentrated iron removal is carried out by adopting an electromagnetic dry powder iron remover with the medium node field intensity up to 13000GS, and the magnetic impurity (Fe) in the product is less than or equal to 0.5 ppm.
The obtained filtrate and washing liquid are treated step by step, the wastewater is concentrated through RO (reverse osmosis), the produced fresh water is recycled, the water cost is saved, the concentrated water is subjected to MVR (multiple effect evaporation) system to obtain byproducts of ammonium sulfate and ammonium phosphate which are high-quality fertilizer raw materials, the ammonium sulfate and the ammonium phosphate can be used for agricultural organic fertilizers and water-soluble fertilizers, and half of the sewage treatment cost is recovered.
Secondly, in the pyrogenic process synthesis stage of the lithium iron phosphate material, low-cost Li is adopted3PO4And H3PO4Common and expensive Li as substitute material2CO3And carrying out ball milling, spray drying, high-temperature calcination (under nitrogen protection), airflow crushing, iron removal and packaging to obtain the battery-grade lithium iron phosphate.
The battery-grade lithium phosphate used by the obtained lithium iron phosphate material not only solves the problem of a lithium source, but also supplements a phosphorus source, and the material cost is lower than that of the battery-grade lithium carbonate used alone by more than 20%. Compared with the traditional process method, the compaction density and the specific capacity of the obtained lithium iron phosphate material are more coordinated and improved to a certain extent.
Through comprehensive calculation, the value of the by-product of the anhydrous iron phosphate is calculated, by adopting the process, the cost of each ton of iron phosphate is lower than 5000 yuan, while the cost of each ton of iron phosphate in the conventional process is generally 8000-; the cost of each ton of lithium iron phosphate is lower than 17000 yuan, the current power type lithium iron phosphate is 3.5-3.7 ten thousand yuan/ton, the energy storage type lithium iron phosphate is 2.5-2.8 ten thousand yuan/ton, and the integral price advantage is very obvious.
Preferably, the mixed powder material obtained in the step (b) is baked under the heat preservation condition of 720-780 ℃, and 730 ℃, 740 ℃, 750 ℃, 760 ℃ or 770 ℃ can be selected.
Preferably, in the step (a), the ferrous sulfate solution is prepared by dissolving, reducing, filtering and clarifying ferrous sulfate heptahydrate crystals which are titanium white byproducts.
The ferrous sulfate heptahydrate crystal is a titanium white byproduct, and due to the fact that the titanium white byproduct is large in amount, low in utilization value and serious in environmental pollution, the problem of reasonable recycling of resources is effectively solved, and production cost is reduced.
Preferably, iron powder or low carbon steel is used in the reduction process, and the pH value of the solution is kept between 3.5 and 4.5; the pH of the solution may also be selected to be 3.7, 3.8, 3.9, 4.1, 4.2, 4.3 or 4.4.
Preferably, the concentration of the ferrous sulfate solution is 250-310g/L, and 260g/L, 270g/L, 280g/L, 290g/L, 300g/L or 305g/L can be selected.
Preferably, in step (a), the phosphate salt comprises at least one of ammonium phosphate, diammonium phosphate and ammonium dihydrogen phosphate.
Preferably, the phosphate solution has a pH of 7.0-9.0; alternatively, 7.5, 7.8, 8.2, 8.5 or 8.8 may be used.
Preferably, the mass concentration of phosphorus in the phosphate solution is 8% -12%, and 8.5%, 9%, 9.5%, 10%, 10.5% or 11% can be selected.
Preferably, in step (a), during the synthesis reaction, the molar ratio of iron to phosphorus in the reaction solution system is 0.97-1.0, and 0.98 or 0.99 can be selected.
Preferably, in the step (a), during the synthesis reaction, the temperature of the reaction solution system is 45-55 ℃, and 46 ℃, 47 ℃, 49 ℃, 51 ℃, 53 ℃ and 55 ℃ can be selected; more preferably, the time of the synthesis reaction is 60-80min, and can be selected from 65min, 68min, 71min, 74min, 77min or 79 min.
Preferably, in the step (a), the temperature of the solution system during the aging is 90-98 ℃, and 91 ℃, 92 ℃, 93 ℃, 94 ℃, 95 ℃, 96 ℃ or 97 ℃ can be selected; more preferably, the solution system is heated with steam.
Preferably, in step (a), the aging time is 2-4h, and 2.5h, 3h or 3.5h can be selected.
Preferably, in step (a), the drying is flash drying.
Preferably, in step (a), the washed filter cake is washed by pure water, the washing end point pH is 3.3 +/-0.5, and the conductivity is less than or equal to 300 us.
Preferably, the calcining temperature is 550-600 ℃, 560 ℃, 570 ℃, 580 ℃ or 590 ℃, and the time is 2-3h, and 2.5h can be selected; more preferably, the temperature of the calcination is 560-590 ℃.
Preferably, the specific surface area SSA of the anhydrous ferric phosphate and ferric oxide mixture is 8.0-10.0m2G, optionally 8.5m2/g、9.0m2G or 9.5m2The particle diameter D50 is 3-5 μm, and 4 μm can be selected.
Preferably, in the step (b), the molar ratio of each element in the mixed slurry is P: Fe: Li: C ═ 1.0 (0.97-1.00): (1.00-1.05): (0.40-0.50).
Preferably, in step (b), the pH of the mixed slurry is 8.0 to 10.0; alternatively 8.5, 8.8, 9.1, 9.4 or 9.8.
Preferably, in step (b), the nano-sized mixed slurry has a particle size of D50 ≦ 0.4 μm.
Preferably, in step (b), the particle diameter D50 of the mixed powder material is 10 to 30 μm, and may be 12 μm, 16 μm, 18 μm, 21 μm, 25 μm, or 27 μm.
Preferably, in the step (b), the drying is spray drying, and the inlet air temperature of the spray drying is 200 ℃ to 250 ℃, and can also be selected from 210 ℃, 220 ℃, 230 ℃, 240 ℃ or 245 ℃; the air outlet temperature is 85-90 ℃, and 86 ℃, 88 ℃ or 89 ℃ can also be selected.
Preferably, in the step (c), the heat preservation roasting time is 6-12 h; 7h, 8h, 9h, 10h or 11h can also be selected.
In the heat preservation roasting process, high-temperature solid phase reaction and carbonization reaction occur to generate the lithium iron phosphate material with a complete coated carbon layer.
Preferably, the heat preservation roasting process is carried out under a protective atmosphere; more preferably, the protective atmosphere comprises at least one of nitrogen, argon and helium.
Preferably, in step (c), the particle size D50 of the lithium iron phosphate is (1.1 ± 0.5) μm, and 0.7 μm, 0.9 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, or 1.5 μm may be selected.
The application also provides the application of the lithium iron phosphate prepared by the preparation method of the lithium iron phosphate in the preparation of the lithium ion battery anode. The process flow for preparing the lithium ion battery anode can be simplified, the cost of the prepared raw materials is saved, and the compaction density and the specific capacity of the prepared lithium ion battery anode are improved.
Compared with the prior art, the invention has the beneficial effects that:
(1) the preparation method of the lithium iron phosphate provided by the invention is simple and feasible, has short process, can realize one-step synthesis of anhydrous iron phosphate in an inorganic system, does not use steam and oxidant in the synthesis process, simplifies the process flow, has small wastewater generation amount, effectively reduces the cost, and the anhydrous iron phosphate prepared by the preparation method has good dispersibility and more uniform particle size distribution. Meanwhile, in the pyrogenic synthesis stage of the lithium iron phosphate material, low-cost Li is adopted3PO4And H3PO4Commonly used and relatively expensive Li as substitute material2CO3The cost is lower, and the comprehensive performances of the material such as compaction density, specific capacity and the like are ensured.
(2) The battery-grade anhydrous ferric phosphate and ferric oxide mixture prepared by the preparation method of the lithium ferric phosphate provided by the invention has the advantages of good dispersibility, high purity, uniform particle size distribution and the like.
(3) According to the preparation method of the lithium iron phosphate, the ferrous sulfate heptahydrate crystal is used as the titanium white byproduct, and the problems of large amount of the titanium white byproduct, low utilization value and serious environmental pollution are effectively solved.
(4) According to the preparation method of the lithium iron phosphate, the battery-grade lithium phosphate used by the obtained lithium iron phosphate material solves the problem of a lithium source, and supplements a phosphorus source, and the material cost is lower than that of the battery-grade lithium carbonate used alone by more than 20%. Compared with the traditional process method, the compaction density and the specific capacity of the obtained lithium iron phosphate material are more coordinated and improved to a certain extent.
(5) According to the preparation method of the lithium iron phosphate, the cost of each ton of the iron phosphate is lower than 5000 yuan, compared with the cost of each ton of the iron phosphate in the conventional process, the cost is reduced by 3000-; moreover, the cost of each ton of lithium iron phosphate is lower than 17000 yuan, the current power type lithium iron phosphate is 3.5-3.7 ten thousand yuan/ton, the energy storage type lithium iron phosphate is 2.5-2.8 ten thousand yuan/ton, and the whole price advantage is very obvious.
(6) The invention also provides the application of the lithium iron phosphate prepared by the preparation method of the lithium iron phosphate in preparing the lithium ion battery anode, so that the process flow is simplified, the preparation cost is saved, and the prepared lithium ion battery anode has high compaction density and specific capacity.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is an SEM image of lithium iron phosphate provided in embodiment 1 of the present invention;
fig. 2 is an SEM image of lithium iron phosphate provided in embodiment 2 of the present invention;
fig. 3 is an SEM image of lithium iron phosphate provided in embodiment 3 of the present invention;
fig. 4 is an SEM image of lithium iron phosphate provided in embodiment 4 of the present invention;
fig. 5 is an SEM image of lithium iron phosphate provided in embodiment 5 of the present invention;
fig. 6 is another SEM image of lithium iron phosphate provided in embodiment 5 of the present invention;
fig. 7 is an SEM image of lithium iron phosphate provided in comparative example 1 of the present invention.
Detailed Description
The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and the detailed description, but those skilled in the art will understand that the following described embodiments are some, not all, of the embodiments of the present invention, and are only used for illustrating the present invention, and should not be construed as limiting the scope of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
Example 1
The preparation method of lithium iron phosphate provided by the embodiment comprises the following steps:
(1) dissolving and reducing (in the reduction process, using iron powder and keeping the pH value of the solution to be 3.5), filtering and clarifying the titanium white byproduct ferrous sulfate heptahydrate crystal to obtain a pure ferrous sulfate solution with the mass concentration of 250 g/L; and simultaneously dissolving ammonium dihydrogen phosphate into a certain amount of pure water, adding ammonia water to adjust the pH of the solution to 7.2, and preparing into a phosphate solution with the phosphorus content of 10%.
(2) Respectively heating a ferrous sulfate solution and a phosphate solution with water to adjust the ferrous sulfate solution and the phosphate solution to certain concentrations, maintaining the temperature of the two solutions at 45 ℃ and the molar ratio of iron to phosphorus at 0.97, synchronously adding the two solutions into a closed reactor for synthesis, reacting for 60min, then entering a reaction kettle for continuous aging, raising the temperature to 90 ℃ with steam under the condition of stirring, and continuing the reaction for 2h to obtain a reaction material.
(3) Filtering the reaction material by a filter press to obtain a filter cake, continuously adding pure water into the filter press containing the filter cake for washing, wherein the washing end point pH is 3.5, the conductivity is less than or equal to 300us, after washing, carrying out flash evaporation drying on the filter cake, calcining by a rotary furnace (the calcining temperature is 600 ℃, the calcining time is 2 hours), crushing, screening and deironing to obtain SSA (8.9 m)2(ii) anhydrous iron phosphate and iron sesquioxide having a particle size D50 of 4.2 [ mu ] mAn iron mixture.
(4) Mixing the mixture obtained in the step (3) and Li3PO4、H3PO4Adding the mixed slurry into a glucose solution in sequence to obtain mixed slurry, wherein the molar ratio of elements P to Fe to Li to C in the mixed slurry is 1.0:1.0:1.00:0.40, adding a small amount of industrial phosphoric acid, adjusting the pH of the mixed slurry to 8, performing coarse and fine grinding for two stages for 5 hours to obtain nanoscale mixed slurry (D50 is less than or equal to 0.4 mu m), conveying the nanoscale mixed slurry into centrifugal spray drying equipment (the inlet air temperature of spray drying is 200 ℃, the outlet air temperature is 85 ℃), and quickly dehydrating to obtain a mixed powder material D50 with good fluidity and uniform particles, wherein the D50 is 10 mu m.
(5) And (3) roasting the mixed powder material obtained in the step (4) at 700 ℃ in a kiln with a nitrogen protective atmosphere, roasting for 12h at the maintained temperature, crushing to D50 of 1.1 mu m, and performing rear-end treatment such as batch mixing, dry powder iron removal, packaging and the like to obtain the lithium iron phosphate.
SEM detection was performed on the lithium iron phosphate prepared in example 1, and the detection result is shown in fig. 1.
As can be seen from figure 1, the lithium iron phosphate anode material prepared by the method has the advantages of uniform particles, reasonable ball matching, small porosity, primary particle size of about 0.3-0.5 mu m, and uniform carbon layer coating, and the lithium iron phosphate anode material prepared by the method has high compaction density and excellent electrical property.
Example 2
The preparation method of lithium iron phosphate provided by the embodiment comprises the following steps:
(1) dissolving and reducing (in the reduction process, using iron powder and keeping the pH value of the solution to be 3.5), filtering and clarifying the titanium white byproduct ferrous sulfate heptahydrate crystal to obtain a pure ferrous sulfate solution with the mass concentration of 280 g/L; and dissolving diammonium phosphate in a certain amount of pure water, adding ammonia water to adjust the pH of the solution to 8.8, and preparing a phosphate solution with the phosphorus content of 8%.
(2) Respectively heating a ferrous sulfate solution and a phosphate solution with water to adjust the ferrous sulfate solution and the phosphate solution to certain concentrations, maintaining the temperature of the two solutions at 55 ℃ and the molar ratio of iron to phosphorus at 0.98, synchronously adding the two solutions into a closed reactor for synthesis, reacting for 80min, then entering a reaction kettle for continuous aging, raising the temperature to 95 ℃ with steam under the condition of stirring, and continuing the reaction for 4h to obtain a reaction material.
(3) Filtering the reaction material by a filter press to obtain a filter cake, continuously adding pure water into the filter press containing the filter cake for washing, wherein the washing end point pH is 3.5, the conductivity is less than or equal to 300us, after washing, carrying out flash evaporation drying on the filter cake, calcining by a rotary furnace (the calcining temperature is 580 ℃ for 2.5h), crushing, screening and deironing to obtain SSA (8.9 m)2(iii) a mixture of anhydrous iron phosphate and ferric oxide having a particle size D50 of 4.3 μm/g.
(4) Mixing the mixture obtained in the step (3) and Li3PO4、H3PO4Adding the mixed slurry into a glucose solution in sequence to obtain a mixed slurry, wherein the molar ratio of elements P to Fe to Li to C is 1.0:0.98:1.05:0.40, adding a small amount of industrial phosphoric acid, adjusting the pH of the mixed slurry to 9, performing coarse and fine grinding for two stages for 5 hours to obtain a nanoscale mixed slurry (D50 is less than or equal to 0.4 mu m), conveying the nanoscale mixed slurry into centrifugal spray drying equipment (the inlet air temperature of spray drying is 250 ℃ and the outlet air temperature is 90 ℃), and quickly dehydrating to obtain a mixed powder material D50 which is good in fluidity and uniform in particles and is 20 mu m.
(5) And (3) roasting the mixed powder material obtained in the step (4) at 700 ℃ in a kiln with argon protective atmosphere, roasting for 6h at the maintained temperature, crushing to D50 of 1.3 mu m, and performing rear-end treatment such as batch mixing, dry powder iron removal, packaging and the like to obtain the lithium iron phosphate.
XRD detection was performed on the lithium iron phosphate prepared in example 2, and the detection result is shown in fig. 2.
As can be seen from FIG. 2, the size of the primary particles of the lithium iron phosphate anode material prepared by the method is about 0.2-0.5 μm, and carbon uniformly coats the surfaces of the lithium iron phosphate particles.
Example 3
The preparation method of lithium iron phosphate provided by the embodiment comprises the following steps:
(1) dissolving and reducing (in the reduction process, using iron powder and keeping the pH of the solution at 4), filtering and clarifying the titanium white byproduct ferrous sulfate heptahydrate crystal to obtain a pure ferrous sulfate solution with the mass concentration of 310 g/L; meanwhile, ammonium phosphate is dissolved in a certain amount of pure water, ammonia water is added to adjust the pH value of the solution to 8.0, and a phosphate solution with the phosphorus content of 12% is prepared.
(2) Respectively heating a ferrous sulfate solution and a phosphate solution with water to adjust the ferrous sulfate solution and the phosphate solution to certain concentrations, maintaining the temperature of the two solutions at 48 ℃ and the molar ratio of iron to phosphorus at 1, synchronously adding the two solutions into a closed reactor for synthesis, reacting for 70min, then entering a reaction kettle for continuous aging, raising the temperature to 98 ℃ with steam under the condition of stirring, and continuing the reaction for 2.5h to obtain a reaction material.
(3) Filtering the reaction material by a filter press to obtain a filter cake, continuously adding pure water into the filter press containing the filter cake for washing, wherein the washing end point pH is 3.3, the conductivity is less than or equal to 300us, after washing, carrying out flash evaporation drying on the filter cake, calcining by a rotary furnace (the calcining temperature is 550 ℃, the calcining time is 3h), crushing, screening and deironing to obtain SSA (9.3 m)2(iii) a mixture of anhydrous iron phosphate and ferric oxide having a particle size D50 of 4.2 μm/g.
(4) Mixing the mixture obtained in the step (3) and Li3PO4、H3PO4Adding the mixed slurry into a glucose solution in sequence to obtain mixed slurry, wherein the molar ratio of elements P to Fe to Li to C in the mixed slurry is 1.0:0.98:1.00:0.50, adding a small amount of industrial phosphoric acid, adjusting the pH of the mixed slurry to 10, performing coarse and fine grinding for two stages for 5 hours to obtain nanoscale mixed slurry (D50 is less than or equal to 0.4 mu m), conveying the nanoscale mixed slurry into centrifugal spray drying equipment (the inlet air temperature of spray drying is 220 ℃ and the outlet air temperature is 87 ℃), and quickly dehydrating to obtain a mixed powder material D50 with good fluidity and uniform particles, wherein the D50 is 28 mu m.
(5) And (3) roasting the mixed powder material obtained in the step (4) at 700 ℃ in a kiln with a nitrogen protective atmosphere, roasting for 8h at a constant temperature, crushing to D50 of 1.4 mu m, and performing rear-end treatment such as batch mixing, dry powder iron removal, packaging and the like to obtain the lithium iron phosphate.
XRD detection was performed on the lithium iron phosphate prepared in example 3, and the detection result is shown in fig. 3.
As can be seen from fig. 3, the lithium iron phosphate anode material prepared by the method has different sizes, but has reasonable matching of the large balls and the small balls and low porosity, and the lithium iron phosphate anode material prepared by the method has high compaction density and excellent electrical property.
Example 4
The preparation method of lithium iron phosphate provided by the embodiment comprises the following steps:
(1) dissolving and reducing a titanium dioxide byproduct ferrous sulfate heptahydrate crystal (low-carbon steel is used in the reduction process, and the pH value of the solution is kept at 3.8), filtering and clarifying to obtain a pure ferrous sulfate solution with the mass concentration of 275 g/L; and simultaneously dissolving ammonium dihydrogen phosphate into a certain amount of pure water, adding ammonia water to adjust the pH of the solution to 7.5, and preparing into a phosphate solution with the phosphorus content of 9%.
(2) Respectively heating a ferrous sulfate solution and a phosphate solution with water to adjust the ferrous sulfate solution and the phosphate solution to certain concentrations, maintaining the temperature of the two solutions at 50 ℃ and the molar ratio of iron to phosphorus at 0.99, synchronously adding the two solutions into a closed reactor for synthesis, reacting for 65min, then entering a reaction kettle for continuous aging, raising the temperature to 93 ℃ with steam under the condition of stirring, and continuing the reaction for 3.5h to obtain a reaction material.
(3) Filtering the reaction material by a filter press to obtain a filter cake, continuously adding pure water into the filter press containing the filter cake for washing, wherein the washing end point pH is 3.8, the conductivity is less than or equal to 300us, after washing, carrying out flash evaporation drying on the filter cake, calcining by a rotary furnace (the calcining temperature is 570 ℃, the calcining time is 2 hours), crushing, screening and deironing to obtain SSA (8.9 m)2(iii) a mixture of anhydrous iron phosphate and ferric oxide having a particle size D50 of 4.6 μm/g.
(4) Mixing the mixture obtained in the step (3) and Li3PO4、H3PO4Sequentially adding the glucose solution into a mixed slurry to obtain a mixed slurry, wherein the molar ratio of the elements in the mixed slurry is P, Fe, Li and C is 1.0:0.98:1.03:0.45, and adding a small amount of the mixed slurryThe industrial phosphoric acid is prepared by adjusting the pH value of the mixed slurry to 8.5, grinding the mixed slurry for 5 hours in a coarse grinding and fine grinding way to obtain the nanoscale mixed slurry (D50 is less than or equal to 0.4 mu m), conveying the nanoscale mixed slurry into centrifugal spray drying equipment (the air inlet temperature of spray drying is 230 ℃ and the air outlet temperature is 88 ℃), and quickly dehydrating to obtain the mixed powder material D50 with good fluidity and uniform particles, wherein the D50 is 15 mu m.
(5) And (3) roasting the mixed powder material obtained in the step (4) at 700 ℃ in a kiln with a nitrogen protective atmosphere, roasting for 10h at the maintained temperature, crushing to D50 of 1.6 mu m, and performing rear-end treatment such as batch mixing, dry powder iron removal, packaging and the like to obtain the lithium iron phosphate.
XRD detection was performed on the lithium iron phosphate prepared in example 4, and the detection result is shown in fig. 4.
As can be seen from FIG. 4, the size of the lithium iron phosphate anode material prepared by the method is 200nm-400nm, carbon uniformly wraps the surface of the lithium iron phosphate, and the lithium iron phosphate anode material prepared by the method has high compaction density and excellent electrical property.
Example 5
The preparation method of lithium iron phosphate provided by the embodiment comprises the following steps:
(1) dissolving and reducing (in the reduction process, using iron powder and keeping the pH value of the solution to be 3.6), filtering and clarifying the titanium white byproduct ferrous sulfate heptahydrate crystal to obtain a pure ferrous sulfate solution with the mass concentration of 290 g/L; and simultaneously dissolving ammonium dihydrogen phosphate into a certain amount of pure water, adding ammonia water to adjust the pH of the solution to 8.3, and preparing into a phosphate solution with the phosphorus content of 11%.
(2) Respectively heating a ferrous sulfate solution and a phosphate solution with water to adjust the ferrous sulfate solution and the phosphate solution to certain concentrations, maintaining the temperature of the two solutions at 53 ℃ and the molar ratio of iron to phosphorus at 0.97, synchronously adding the two solutions into a closed reactor for synthesis, reacting for 75min, then entering a reaction kettle for continuous aging, raising the temperature to 96 ℃ with steam under the condition of stirring, and continuing the reaction for 3h to obtain a reaction material.
(3) Filtering the reaction material by a filter press to obtain a filter cake, and continuously adding pure water into the filter press containing the filter cakeWashing with water, washing to obtain final pH of 3.6 and conductivity of 300us or less, flash drying, calcining in rotary kiln at 590 deg.C for 3 hr, pulverizing, sieving and removing iron to obtain SSA of 9.1m2(iii) a mixture of anhydrous iron phosphate and ferric oxide having a particle size D50 of 4.1 [ mu ] m.
(4) Mixing the mixture obtained in the step (3) and Li3PO4、H3PO4Adding the mixed slurry into a glucose solution in sequence to obtain mixed slurry, wherein the molar ratio of elements P to Fe to Li to C is 1.0:0.97:1.05:0.50, adding a small amount of industrial phosphoric acid, adjusting the pH of the mixed slurry to 9.2, grinding the mixed slurry for 5 hours in a coarse grinding stage and a fine grinding stage to obtain nanoscale mixed slurry (D50 is less than or equal to 0.4 mu m), conveying the nanoscale mixed slurry into centrifugal spray drying equipment (the inlet air temperature of spray drying is 240 ℃ and the outlet air temperature is 89 ℃), and quickly dehydrating to obtain a mixed powder material D50 which is good in fluidity and uniform in particles and 23 mu m.
(5) And (3) roasting the mixed powder material obtained in the step (4) at 700 ℃ in a kiln with a nitrogen protective atmosphere, roasting for 9h at a constant temperature, crushing to D50 of 1.5 mu m, and performing rear-end treatment such as batch mixing, dry powder iron removal, packaging and the like to obtain the lithium iron phosphate.
XRD detection was performed on the lithium iron phosphate prepared in example 5, and the detection result is shown in fig. 5.
As can be seen from FIG. 5, the size of the lithium iron phosphate cathode material prepared by the method is 200nm-500nm, the porosity is relatively low, and the lithium iron phosphate cathode material prepared by the method has high compaction density and excellent electrical property.
Comparative example 1
The preparation method of the lithium iron phosphate provided by the comparative example is basically the same as that of the example 5, and the difference is only that in the step (2), hydrogen peroxide is added while the phosphate solution is added. Wherein the mass fraction of the hydrogen peroxide is 20%, and in the reaction process, Fe and H2O2The molar ratio of (A) to (B) is 2:1 to 1: 2.
Test example 1
Physicochemical parameter detection was performed on the lithium iron phosphate prepared in each of the above examples and comparative examples, and the results are shown in table 1 below.
Table 1 results of measuring physicochemical parameters of lithium iron phosphate in examples 1 to 5 and comparative example 1
As can be seen from table 1, the lithium iron phosphate prepared by the present invention has a large tap density, a high first discharge specific capacity, and a high first efficiency, while the lithium iron phosphate prepared by the comparative example 1 has a low tap density, a low first discharge specific capacity, and a low first efficiency.
Test example 2
SEM examination was performed on lithium iron phosphate prepared in example 5 and comparative example 1, and the examination results are shown in fig. 6 and 7. As can be seen from fig. 6, the lithium iron phosphate prepared in embodiment 5 of the present invention has good dispersibility and uniform particle size distribution. As can be seen from fig. 7, the lithium iron phosphate prepared in comparative example 1 has poor dispersibility and relatively non-uniform particle size distribution.
While particular embodiments of the present invention have been illustrated and described, it will be appreciated that the above embodiments are merely illustrative of the technical solution of the present invention and are not restrictive; those of ordinary skill in the art will understand that: modifications may be made to the above-described embodiments, or equivalents may be substituted for some or all of the features thereof without departing from the spirit and scope of the present invention; the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention; it is therefore intended to cover in the appended claims all such alternatives and modifications that are within the scope of the invention.
Claims (10)
1. The preparation method of the lithium iron phosphate is characterized by comprising the following steps:
(a) mixing a ferrous sulfate solution and a phosphate solution and carrying out a synthesis reaction, aging the solution after the synthesis reaction, carrying out solid-liquid separation on the aged solution, washing a filter cake, drying, calcining, crushing, screening and removing iron to obtain a mixture of anhydrous iron phosphate and ferric oxide;
(b) the mixture obtained in step (a) and Li3PO4、H3PO4Sequentially adding glucose solution to obtain mixed slurry, grinding the mixed slurry to obtain nanoscale mixed slurry, and drying the nanoscale mixed slurry to obtain a mixed powder material;
(c) and (c) roasting the mixed powder material obtained in the step (b) at the temperature of 700 ℃ and 800 ℃, and crushing to obtain the lithium iron phosphate.
2. The method for preparing lithium iron phosphate according to claim 1, wherein in step (a), the ferrous sulfate solution is prepared by dissolving, reducing, filtering and clarifying ferrous sulfate heptahydrate crystal as a titanium dioxide byproduct;
preferably, iron powder or low carbon steel is used in the reduction process, and the pH value of the solution is kept between 3.5 and 4.5;
preferably, the concentration of the ferrous sulfate solution is 250-310 g/L.
3. The method for preparing lithium iron phosphate according to claim 1, wherein, in the step (a), the phosphate comprises at least one of ammonium phosphate, diammonium phosphate, and ammonium dihydrogen phosphate;
preferably, the phosphate solution has a pH of 7.0-9.0;
preferably, the mass concentration of phosphorus in the phosphate solution is 8-12%.
4. The method for preparing lithium iron phosphate according to claim 1, wherein in the step (a), during the synthesis reaction, the molar ratio of iron to phosphorus in the reaction solution system is 0.97-1.0;
preferably, during the synthesis reaction, the temperature of the reaction solution system is 45-55 ℃; more preferably, the time of the synthesis reaction is 60-80 min.
5. The method for preparing lithium iron phosphate according to claim 1, wherein in the step (a), the temperature of the solution system is 90-98 ℃ during the aging process; more preferably, the solution system is heated with steam;
preferably, the aging time is 2-4 h;
preferably, the drying is flash drying.
6. The preparation method of lithium iron phosphate according to claim 1, wherein in step (a), the washing filter cake is washed with pure water, the washing end point pH is 3.3 ± 0.5, and the conductivity is less than or equal to 300 us;
preferably, the calcining temperature is 550-600 ℃, and the time is 2-3 h;
preferably, the specific surface area SSA of the anhydrous ferric phosphate and ferric oxide mixture is 8.0-10.0m2(iii) a particle diameter D50 of 3-5 [ mu ] m.
7. The method for producing lithium iron phosphate according to claim 1, wherein in the step (b), the molar ratio of each element in the mixed slurry is P: Fe: Li: C ═ 1.0 (0.97-1.00): (1.00-1.05): (0.40-0.50);
preferably, the pH of the mixed slurry is 8.0 to 10.0;
preferably, the particle size of the nano-scale mixed slurry is D50 ≤ 0.4 μm;
preferably, the particle diameter D50 of the mixed powder material is 10-30 μm;
preferably, in the step (b), the drying is spray drying, the inlet air temperature of the spray drying is 200 ℃ and 250 ℃, and the outlet air temperature is 85-90 ℃.
8. The method for preparing lithium iron phosphate according to claim 1, wherein in the step (c), the time for the heat-preservation roasting is 6-12 h;
preferably, the heat preservation roasting process is carried out under a protective atmosphere; more preferably, the protective atmosphere comprises at least one of nitrogen, argon and helium.
9. The method for producing lithium iron phosphate according to claim 1, wherein in step (c), the particle diameter D50 of the lithium iron phosphate is (1.1 ± 0.5) μm.
10. Use of the lithium iron phosphate prepared by the method for preparing lithium iron phosphate according to any one of claims 1 to 9 for preparing a positive electrode of a lithium ion battery.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111107692.6A CN113772650B (en) | 2021-09-22 | 2021-09-22 | Preparation method and application of lithium iron phosphate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111107692.6A CN113772650B (en) | 2021-09-22 | 2021-09-22 | Preparation method and application of lithium iron phosphate |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113772650A true CN113772650A (en) | 2021-12-10 |
| CN113772650B CN113772650B (en) | 2023-04-28 |
Family
ID=78852791
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111107692.6A Active CN113772650B (en) | 2021-09-22 | 2021-09-22 | Preparation method and application of lithium iron phosphate |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113772650B (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114572955A (en) * | 2022-03-24 | 2022-06-03 | 广东光华科技股份有限公司 | Battery-grade aluminum-containing iron phosphate and preparation method thereof, lithium iron phosphate positive electrode material and preparation method thereof, and battery |
| CN114702020A (en) * | 2022-05-09 | 2022-07-05 | 兰州兰石中科纳米科技有限公司 | Production line for preparing nano lithium iron phosphate from waste ferrous sulfate in titanium dioxide production |
| CN114933290A (en) * | 2022-06-17 | 2022-08-23 | 德阳川发龙蟒新材料有限公司 | Anhydrous ferric phosphate and ferric oxide mixture, synthesis method thereof, lithium iron phosphate, preparation method and application thereof |
| CN115924879A (en) * | 2023-01-18 | 2023-04-07 | 河南佰利新能源材料有限公司 | Method for recycling lithium iron phosphate from scrap lithium iron phosphate material |
| CN116281917A (en) * | 2023-03-01 | 2023-06-23 | 湖北宇浩高科新材料有限公司 | Battery-grade anhydrous ferric phosphate, preparation method and application thereof, and preparation method of lithium iron phosphate |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109326777A (en) * | 2018-08-28 | 2019-02-12 | 北京泰丰先行新能源科技有限公司 | A kind of preparation method of lithium iron phosphate cell material |
-
2021
- 2021-09-22 CN CN202111107692.6A patent/CN113772650B/en active Active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109326777A (en) * | 2018-08-28 | 2019-02-12 | 北京泰丰先行新能源科技有限公司 | A kind of preparation method of lithium iron phosphate cell material |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114572955A (en) * | 2022-03-24 | 2022-06-03 | 广东光华科技股份有限公司 | Battery-grade aluminum-containing iron phosphate and preparation method thereof, lithium iron phosphate positive electrode material and preparation method thereof, and battery |
| CN114702020A (en) * | 2022-05-09 | 2022-07-05 | 兰州兰石中科纳米科技有限公司 | Production line for preparing nano lithium iron phosphate from waste ferrous sulfate in titanium dioxide production |
| CN114702020B (en) * | 2022-05-09 | 2023-07-21 | 兰州兰石中科纳米科技有限公司 | Production line for preparing nano lithium iron phosphate from titanium dioxide auxiliary waste ferrous sulfate |
| CN114933290A (en) * | 2022-06-17 | 2022-08-23 | 德阳川发龙蟒新材料有限公司 | Anhydrous ferric phosphate and ferric oxide mixture, synthesis method thereof, lithium iron phosphate, preparation method and application thereof |
| CN115924879A (en) * | 2023-01-18 | 2023-04-07 | 河南佰利新能源材料有限公司 | Method for recycling lithium iron phosphate from scrap lithium iron phosphate material |
| CN116281917A (en) * | 2023-03-01 | 2023-06-23 | 湖北宇浩高科新材料有限公司 | Battery-grade anhydrous ferric phosphate, preparation method and application thereof, and preparation method of lithium iron phosphate |
| CN116281917B (en) * | 2023-03-01 | 2024-02-09 | 湖北宇浩高科新材料有限公司 | Battery-grade anhydrous ferric phosphate, preparation method and application thereof, and preparation method of lithium iron phosphate |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113772650B (en) | 2023-04-28 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN113772650B (en) | Preparation method and application of lithium iron phosphate | |
| CN112645299A (en) | Preparation method and application of iron phosphate | |
| CN1208241C (en) | Wet chemistry method for preparing lithium iron phosphate | |
| CN112499609A (en) | Method for preparing iron phosphate by using waste lithium iron phosphate anode powder lithium extraction slag and application | |
| CN113148969B (en) | Doped lithium iron manganese phosphate-carbon composite material and preparation method thereof | |
| CN110357057B (en) | Flaky iron phosphate and preparation method and application thereof | |
| CN113104827B (en) | Method for preparing battery-grade anhydrous iron phosphate from industrial ammonium phosphate clear solution or industrial ammonium phosphate mother solution | |
| WO2024060549A1 (en) | Method for continuously preparing iron phosphate and use | |
| CN110482515B (en) | Preparation method of low-cost lithium iron phosphate | |
| CN105895914A (en) | Preparation method of iron phosphate dihydrate | |
| CN113460987A (en) | Doped iron phosphate and preparation method and application thereof | |
| GB2620048A (en) | Preparation method for sodium ferrovanadium phosphate material and application thereof | |
| CN114613965A (en) | Preparation method and application of lithium iron phosphate/carbon composite material | |
| CN111498823A (en) | Method for preparing battery-grade iron phosphate by using iron oxide | |
| CN114516625A (en) | Iron phosphate and preparation method and application thereof | |
| CN108557792B (en) | A kind of preparation method of cladded type iron manganese phosphate | |
| Fu et al. | A facile route for the efficient leaching, recovery, and regeneration of lithium and iron from waste lithium iron phosphate cathode materials | |
| CN111792635A (en) | Preparation method of anhydrous iron phosphate | |
| CN115974036A (en) | Spherical lithium ferric manganese phosphate nano-particles and preparation method thereof | |
| CN114933290A (en) | Anhydrous ferric phosphate and ferric oxide mixture, synthesis method thereof, lithium iron phosphate, preparation method and application thereof | |
| CN115259128A (en) | Preparation method of high-compaction high-capacity low-cost lithium iron phosphate | |
| CN115340075A (en) | Method for preparing battery-grade iron phosphate by adopting iron oxide and dilute phosphoric acid | |
| CN115108543A (en) | Method for synthesizing battery-grade iron phosphate | |
| CN116534820B (en) | Method for preparing high-compaction ferric phosphate from industrial monoammonium phosphate and ferrous sulfate | |
| CN109461924A (en) | A kind of method that lithium recycles NCA presoma processed |
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 | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| TR01 | Transfer of patent right | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20240401 Address after: 454150 200 meters east of Haohua Road, Qinbei Industrial Cluster, Xixiang Town, Qinyang City, Jiaozuo City, Henan Province Patentee after: Henan Longbai New Material Technology Co.,Ltd. Country or region after: China Address before: 454150 200m north of the intersection of Jingsi road and Xuelian Road, Fengfeng street, zhongzhan District, Jiaozuo City, Henan Province Patentee before: Henan Baili new energy material Co.,Ltd. Country or region before: China |