CN115259129A - Preparation method of lithium iron phosphate - Google Patents
Preparation method of lithium iron phosphate Download PDFInfo
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- CN115259129A CN115259129A CN202211158881.0A CN202211158881A CN115259129A CN 115259129 A CN115259129 A CN 115259129A CN 202211158881 A CN202211158881 A CN 202211158881A CN 115259129 A CN115259129 A CN 115259129A
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- iron phosphate
- lithium iron
- lithium
- waste
- phosphate
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- 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 97
- 238000002360 preparation method Methods 0.000 title claims abstract description 8
- 239000002699 waste material Substances 0.000 claims abstract description 34
- 239000002245 particle Substances 0.000 claims abstract description 28
- 238000001354 calcination Methods 0.000 claims abstract description 18
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 14
- 238000000034 method Methods 0.000 claims abstract description 12
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims abstract description 11
- 229910052744 lithium Inorganic materials 0.000 claims abstract description 11
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 8
- 238000002156 mixing Methods 0.000 claims abstract description 7
- 239000000463 material Substances 0.000 claims description 36
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 24
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 19
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims description 16
- 229910052698 phosphorus Inorganic materials 0.000 claims description 16
- 239000011574 phosphorus Substances 0.000 claims description 16
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 15
- 229910052742 iron Inorganic materials 0.000 claims description 12
- 238000004519 manufacturing process Methods 0.000 claims description 12
- 238000003756 stirring Methods 0.000 claims description 11
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims description 10
- 239000006185 dispersion Substances 0.000 claims description 10
- 239000007788 liquid Substances 0.000 claims description 10
- 235000003891 ferrous sulphate Nutrition 0.000 claims description 8
- 239000011790 ferrous sulphate Substances 0.000 claims description 8
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 claims description 8
- 229910000359 iron(II) sulfate Inorganic materials 0.000 claims description 8
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 claims description 7
- 229910052808 lithium carbonate Inorganic materials 0.000 claims description 7
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 claims description 6
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 claims description 6
- 150000003839 salts Chemical class 0.000 claims description 6
- WQZGKKKJIJFFOK-GASJEMHNSA-N Glucose Natural products OC[C@H]1OC(O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-GASJEMHNSA-N 0.000 claims description 5
- 229910000147 aluminium phosphate Inorganic materials 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
- 239000008103 glucose Substances 0.000 claims description 5
- 238000010438 heat treatment Methods 0.000 claims description 5
- 235000019837 monoammonium phosphate Nutrition 0.000 claims description 5
- VCJMYUPGQJHHFU-UHFFFAOYSA-N iron(3+);trinitrate Chemical compound [Fe+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O VCJMYUPGQJHHFU-UHFFFAOYSA-N 0.000 claims description 4
- IIPYXGDZVMZOAP-UHFFFAOYSA-N lithium nitrate Chemical compound [Li+].[O-][N+]([O-])=O IIPYXGDZVMZOAP-UHFFFAOYSA-N 0.000 claims description 4
- 238000003825 pressing Methods 0.000 claims description 4
- 239000007787 solid Substances 0.000 claims description 4
- 238000001035 drying Methods 0.000 claims description 3
- 238000011049 filling Methods 0.000 claims description 3
- 239000002202 Polyethylene glycol Substances 0.000 claims description 2
- 229930006000 Sucrose Natural products 0.000 claims description 2
- CZMRCDWAGMRECN-UGDNZRGBSA-N Sucrose Chemical compound O[C@H]1[C@H](O)[C@@H](CO)O[C@@]1(CO)O[C@@H]1[C@H](O)[C@@H](O)[C@H](O)[C@@H](CO)O1 CZMRCDWAGMRECN-UGDNZRGBSA-N 0.000 claims description 2
- 239000006230 acetylene black Substances 0.000 claims description 2
- 238000005119 centrifugation Methods 0.000 claims description 2
- MNNHAPBLZZVQHP-UHFFFAOYSA-N diammonium hydrogen phosphate Chemical compound [NH4+].[NH4+].OP([O-])([O-])=O MNNHAPBLZZVQHP-UHFFFAOYSA-N 0.000 claims description 2
- 229910000388 diammonium phosphate Inorganic materials 0.000 claims description 2
- 235000019838 diammonium phosphate Nutrition 0.000 claims description 2
- 229960002413 ferric citrate Drugs 0.000 claims description 2
- 238000001914 filtration Methods 0.000 claims description 2
- 235000021552 granulated sugar Nutrition 0.000 claims description 2
- 229910021389 graphene Inorganic materials 0.000 claims description 2
- 229910002804 graphite Inorganic materials 0.000 claims description 2
- 239000010439 graphite Substances 0.000 claims description 2
- RUTXIHLAWFEWGM-UHFFFAOYSA-H iron(3+) sulfate Chemical compound [Fe+3].[Fe+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O RUTXIHLAWFEWGM-UHFFFAOYSA-H 0.000 claims description 2
- PVFSDGKDKFSOTB-UHFFFAOYSA-K iron(3+);triacetate Chemical compound [Fe+3].CC([O-])=O.CC([O-])=O.CC([O-])=O PVFSDGKDKFSOTB-UHFFFAOYSA-K 0.000 claims description 2
- NPFOYSMITVOQOS-UHFFFAOYSA-K iron(III) citrate Chemical compound [Fe+3].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O NPFOYSMITVOQOS-UHFFFAOYSA-K 0.000 claims description 2
- 229910000360 iron(III) sulfate Inorganic materials 0.000 claims description 2
- 239000003273 ketjen black Substances 0.000 claims description 2
- XIXADJRWDQXREU-UHFFFAOYSA-M lithium acetate Chemical compound [Li+].CC([O-])=O XIXADJRWDQXREU-UHFFFAOYSA-M 0.000 claims description 2
- 235000011007 phosphoric acid Nutrition 0.000 claims description 2
- 229920001223 polyethylene glycol Polymers 0.000 claims description 2
- 239000002243 precursor Substances 0.000 claims description 2
- 239000005720 sucrose Substances 0.000 claims description 2
- 238000005406 washing Methods 0.000 claims description 2
- 238000005056 compaction Methods 0.000 abstract description 10
- WBJZTOZJJYAKHQ-UHFFFAOYSA-K iron(3+) phosphate Chemical compound [Fe+3].[O-]P([O-])([O-])=O WBJZTOZJJYAKHQ-UHFFFAOYSA-K 0.000 abstract description 9
- 239000002994 raw material Substances 0.000 abstract description 8
- 238000012545 processing Methods 0.000 abstract description 5
- 239000011248 coating agent Substances 0.000 abstract description 2
- 238000000576 coating method Methods 0.000 abstract description 2
- 238000011068 loading method Methods 0.000 abstract description 2
- 230000001376 precipitating effect Effects 0.000 abstract description 2
- 238000001556 precipitation Methods 0.000 abstract description 2
- 239000005955 Ferric phosphate Substances 0.000 abstract 3
- 229940032958 ferric phosphate Drugs 0.000 abstract 3
- 229910000399 iron(III) phosphate Inorganic materials 0.000 abstract 3
- 238000009826 distribution Methods 0.000 description 8
- 238000010902 jet-milling Methods 0.000 description 6
- 229910000398 iron phosphate Inorganic materials 0.000 description 5
- 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 3
- 239000006012 monoammonium phosphate Substances 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 238000004146 energy storage Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000011164 primary particle Substances 0.000 description 2
- 238000001878 scanning electron micrograph Methods 0.000 description 2
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 1
- 239000010405 anode material Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- -1 glucose Chemical compound 0.000 description 1
- 229910001416 lithium ion Inorganic materials 0.000 description 1
- 238000003801 milling Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000007774 positive electrode material Substances 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 239000007790 solid phase Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000001132 ultrasonic dispersion Methods 0.000 description 1
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- 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
- H01M10/54—Reclaiming serviceable parts of waste accumulators
-
- 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
- C01P2004/00—Particle morphology
- C01P2004/01—Particle morphology depicted by an image
- C01P2004/03—Particle morphology depicted by an image obtained by SEM
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/51—Particles with a specific particle size distribution
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/60—Particles characterised by their size
- C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/60—Particles characterised by their size
- C01P2004/62—Submicrometer sized, i.e. from 0.1-1 micrometer
-
- 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
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- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Crystallography & Structural Chemistry (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
The invention provides a preparation method of lithium iron phosphate, which comprises the steps of taking recycled lithium iron phosphate as a raw material, coating a layer of ferric phosphate on the surface of waste lithium iron phosphate by a precipitation method, precipitating and forming a certain amount of ferric phosphate among lithium iron phosphate particles, and then mixing and calcining the ferric phosphate with a lithium source and a carbon source to obtain the lithium iron phosphate with high compaction density and low cost; the particle size of the recovered lithium iron phosphate is larger, the particle size of the newly formed lithium iron phosphate is smaller, and the aim of improving the compaction density is fulfilled through size matching; waste lithium iron phosphate is used as a raw material, so that the raw material cost is low; in addition, the calcining temperature is low, the allowable loading amount is large, and the processing cost can be greatly reduced, so that the raw material cost and the processing cost of the product are extremely low.
Description
Technical Field
The invention relates to the field of lithium ion battery anode materials, in particular to a preparation method of lithium iron phosphate.
Background
The lithium iron phosphate battery has low cost and good cycle performance, and is widely applied to the fields of power automobiles and energy storage. With the continuous development of battery technology, higher requirements are also put forward on lithium iron phosphate as a positive electrode material, lithium iron phosphate for power automobiles requires higher compaction density, and lithium iron phosphate for the energy storage field requires lower cost.
At present, lithium iron phosphate is mainly prepared through a process route of solid-phase iron phosphate and lithium carbonate, and the compaction density of the material is improved by means of improving the granularity of primary particles, optimizing the granularity distribution and the like. If the compaction density is increased by simply increasing the particle size of the primary particles of the lithium iron phosphate material, the electrical property of the material is obviously reduced and may be finally irrevocably lost; if the particle size distribution is optimized through jet milling, the aim of improving the compaction density can be achieved, but the jet milling can damage a carbon layer coated on the surface of the lithium iron phosphate material in the milling process, so that the resistivity of the material is finally improved, and the electrical property of the material is partially reduced.
In addition, it is also a feasible method to select a matched large and small particles to improve the compacted density, and the method has two implementation modes: firstly, mixing iron phosphates with different sizes and then calcining; secondly, iron phosphate with different sizes is calcined with lithium carbonate and then mixed. In the first mode, because the large and small particles are mixed and calcined under the same conditions, the phenomena of overburning or overburning of the large and small particles can occur, and the electrical property of the material can be obviously reduced, so the method is not generally selected; if the second method is selected, calcination followed by mixing, the processing cost is increased.
Disclosure of Invention
In view of this, the invention provides a preparation method of lithium iron phosphate, which can reduce the cost on the premise of ensuring high compaction density.
The technical scheme of the invention is realized as follows: the invention provides a preparation method of lithium iron phosphate, which comprises the following steps,
s1, recovering waste lithium iron phosphate;
s2, dissolving soluble ferric salt in water, adding the lithium iron phosphate obtained in the step S1, and dispersing to obtain a dispersion liquid;
s3, heating the dispersion liquid obtained in the step S2 to 40-80 ℃, stirring, adding hydrogen peroxide and a phosphorus source, keeping the pH value at 1-3 in the adding process, stirring for 4-8h at 80-95 ℃ after materials are added, filtering and washing to obtain a precursor;
s4, adding a lithium source, a carbon source and water to ensure that the molar ratio of lithium to iron is (1.00-1.10): 1, uniformly mixing, drying and filling into a pot;
s5, calcining, and crushing discharged materials to obtain a lithium iron phosphate material with the particle size of 0.6-2.0 mu m.
On the basis of the above technical scheme, preferably, in step S1, the waste lithium iron phosphate includes waste lithium iron phosphate batteries, waste lithium iron phosphate pole pieces, and a waste lithium iron phosphate material generated in the production process of the lithium iron phosphate batteries, wherein the waste lithium iron phosphate batteries are disassembled to obtain the lithium iron phosphate pole pieces, then the lithium iron phosphate pole pieces are calcined in the air at 400-500 ℃ for 2-6 h, then the pole pieces are put into water, the solid content is adjusted to 30-60%, the stirring is performed for 0.5-2h, the pole pieces are taken out, and the lithium iron phosphate material is obtained through standing, centrifugation or filter pressing.
On the basis of the above technical solution, preferably, in the step S1, the particle size of the waste lithium iron phosphate material is 0.5-5 μm, wherein the molar ratio of iron to phosphorus is (0.9-1.05): 1.
on the basis of the above technical solution, preferably, in step S2, the soluble ferric salt is one or a combination of several of ferrous sulfate, ferric nitrate, ferric sulfate, ferric acetate, and ferric citrate.
On the basis of the above technical scheme, preferably, in the step S2, the molar ratio of the soluble ferric salt accounts for 10-30% of the waste lithium iron phosphate.
On the basis of the above technical solution, preferably, in the step S3, the phosphorus source is one or a combination of several of phosphoric acid, ammonium monohydrogen phosphate, and ammonium dihydrogen phosphate.
In addition to the above technical solutions, preferably, in the step S3, the molar ratio of the hydrogen peroxide solution to the phosphorus source is (1-1.5): 1, and the molar ratio of the phosphorus source to the iron is (1-1.1): 1.
On the basis of the above technical solution, preferably, in step S4, the lithium source is selected from one or a combination of several of lithium carbonate, lithium hydroxide, lithium nitrate and lithium acetate.
On the basis of the above technical solution, preferably, in the step S4, the carbon source is selected from one or a combination of several of organic carbon such as glucose, white granulated sugar, sucrose, polyethylene glycol, citric acid, and acetylene black, ketjen black, graphite, and graphene.
On the basis of the above technical scheme, preferably, in the step S5, the calcination temperature is 650 to 800 ℃, and the calcination time is 5 to 15 hours.
On the basis of the above technical solution, preferably, in the step S5, the calcination is performed in a roller kiln.
In addition to the above technical solutions, preferably, in the step S5, jet milling is adopted.
Compared with the prior art, the preparation method of the lithium iron phosphate has the following beneficial effects:
(1) Coating a layer of iron phosphate on the surface of waste lithium iron phosphate by using recovered lithium iron phosphate as a raw material through a precipitation method, precipitating and forming a certain amount of iron phosphate among lithium iron phosphate particles, and then mixing and calcining the iron phosphate with a lithium source and a carbon source to obtain lithium iron phosphate with high compaction density and low cost;
(2) The particle size of the recovered lithium iron phosphate is larger, the particle size of the newly formed lithium iron phosphate is smaller, and the aim of improving the compaction density is fulfilled through size matching;
(3) Waste lithium iron phosphate is used as a raw material, so that the raw material cost is low; in addition, the calcination temperature is low, the allowable loading amount is large, and the processing cost can be greatly reduced, so that the product has extremely low raw material cost and processing cost.
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, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a particle size distribution diagram of a lithium iron phosphate material obtained in example 2;
fig. 2 is an SEM image of the lithium iron phosphate material obtained in example 2.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
Example 1
S1, recovering waste lithium iron phosphate; the method comprises the following steps: the method comprises the steps of firstly disassembling the waste lithium iron phosphate battery to obtain a lithium iron phosphate pole piece, then calcining the lithium iron phosphate pole piece in the air at 450 ℃ for 4 hours, then putting the pole piece into water, adjusting the solid content to 45%, stirring for 1.5 hours, taking out the pole piece, standing, centrifuging or performing filter pressing to obtain the lithium iron phosphate material.
The particle size of the finally obtained waste lithium iron phosphate material is 0.5 mu m, wherein the molar ratio of iron to phosphorus is 1.
S2, dissolving ferrous sulfate in water, adding the lithium iron phosphate obtained in the step S1, and dispersing to obtain a dispersion liquid, wherein the ferrous sulfate accounts for 10% of the molar ratio of the waste lithium iron phosphate;
s3, heating the dispersion liquid obtained in the step S2 to 40 ℃, stirring, adding hydrogen peroxide, monoammonium phosphate and phosphoric acid, wherein the molar ratio of hydrogen peroxide to phosphorus is 1;
s4, adding lithium carbonate, glucose and water to enable the molar ratio of lithium to iron to be 1;
and S5, calcining the mixture for 15 hours at 650 ℃ in a roller kiln, and performing jet milling on the discharged material to obtain a lithium iron phosphate material with the particle size of 0.6-2.0 mu m.
Example 2
S1, recovering waste lithium iron phosphate; and calcining the waste lithium iron phosphate pole piece in the air at 400-500 ℃ for 2-6 h by adopting the waste lithium iron phosphate pole piece, putting the pole piece into water, adjusting the solid content to 30-60%, stirring for 0.5-2h, taking out the pole piece, standing, centrifuging or performing filter pressing to obtain the lithium iron phosphate material.
The particle size of the finally obtained waste lithium iron phosphate material is 2.5 mu m, wherein the molar ratio of iron to phosphorus is 1.
S2, dissolving ferrous sulfate in water, adding the lithium iron phosphate obtained in the step S1, and dispersing to obtain a dispersion liquid, wherein the ferrous sulfate accounts for 20% of the molar ratio of the waste lithium iron phosphate;
s3, heating the dispersion liquid obtained in the step S2 to 60 ℃, stirring, adding hydrogen peroxide, monoammonium phosphate and phosphoric acid, wherein the molar ratio of hydrogen peroxide to phosphorus is 1.2;
s4, adding lithium carbonate, glucose and water to enable the molar ratio of lithium to iron to be 1.05;
and S5, calcining for 10 hours at 720 ℃ in a roller kiln, and performing jet milling on discharged materials to obtain a lithium iron phosphate material with the particle size of 0.6-2.0 microns.
For the lithium iron phosphate material prepared in this example, the particle size distribution thereof was tested, and the particle size distribution diagram shown in fig. 1 was obtained. The particle size distribution is tested by adopting a laser particle size analyzer, water is used as a dispersing agent, the particle size distribution is tested after ultrasonic dispersion is carried out on the prepared lithium iron phosphate material, the light shielding degree is 8-12%, the test is carried out for three times, and the average value is taken as the final result.
Fig. 2 is an SEM image of the lithium iron phosphate material prepared in this embodiment, and as can be seen from fig. 1 and fig. 2, the lithium iron phosphate with a large and small particle size distribution prepared by the present invention can achieve the purpose of high compaction of the material.
Example 3
S1, recycling waste lithium iron phosphate; the method comprises the following steps: the waste lithium iron phosphate is made of a waste lithium iron phosphate material generated in the production process of a lithium iron phosphate battery, and the particle size of the waste lithium iron phosphate material is 5 micrometers, wherein the molar ratio of iron to phosphorus is 1: 1.05.
S2, dissolving ferrous sulfate in water, adding the lithium iron phosphate obtained in the step S1, and dispersing to obtain a dispersion liquid, wherein the ferrous sulfate accounts for 30% of the molar ratio of the waste lithium iron phosphate;
s3, heating the dispersion liquid obtained in the step S2 to 80 ℃, stirring, adding hydrogen peroxide, monoammonium phosphate and phosphoric acid, wherein the molar ratio of hydrogen peroxide to phosphorus is 1.5;
s4, adding lithium carbonate, glucose and water to enable the molar ratio of lithium to iron to be 1.10, uniformly mixing, drying, and filling into a pot;
and S5, calcining the mixture for 5 hours at 800 ℃ in a roller kiln, and performing jet milling on the discharged material to obtain a lithium iron phosphate material with the particle size of 0.6-2.0 mu m.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (10)
1. A preparation method of lithium iron phosphate is characterized by comprising the following steps: which comprises the following steps of (a) preparing,
s1, recovering waste lithium iron phosphate;
s2, dissolving soluble ferric salt in water, adding the lithium iron phosphate obtained in the step S1, and dispersing to obtain a dispersion liquid;
s3, heating the dispersion liquid obtained in the step S2 to 40-80 ℃, stirring, adding hydrogen peroxide and a phosphorus source, keeping the pH value at 1-3 in the adding process, stirring for 4-8h at 80-95 ℃ after materials are added, filtering and washing to obtain a precursor;
s4, adding a lithium source, a carbon source and water to ensure that the molar ratio of lithium to iron is (1.00-1.10): 1, uniformly mixing, drying and filling into a pot;
and S5, calcining, and crushing discharged materials to obtain a lithium iron phosphate material with the particle size of 0.6-2.0 mu m.
2. The method for producing lithium iron phosphate according to claim 1, characterized in that: in the step S1, the waste lithium iron phosphate comprises waste lithium iron phosphate batteries, waste lithium iron phosphate pole pieces and waste lithium iron phosphate materials generated in the production process of the lithium iron phosphate batteries, wherein the waste lithium iron phosphate batteries are disassembled to obtain the lithium iron phosphate pole pieces, then the lithium iron phosphate pole pieces are calcined for 2-6 hours at 400-500 ℃ in the air, then the pole pieces are put into water, the solid content is adjusted to 30-60%, the stirring is carried out for 0.5-2 hours, the pole pieces are taken out, and the lithium iron phosphate materials are obtained through standing, centrifugation or filter pressing.
3. The method for producing lithium iron phosphate according to claim 2, characterized in that: in the step S1, the particle size of the waste lithium iron phosphate is 0.5-5 μm, wherein the molar ratio of iron to phosphorus is (0.9-1.05): 1.
4. the method for producing lithium iron phosphate according to claim 1, characterized in that: in the step S2, the soluble ferric salt is one or a combination of ferrous sulfate, ferric nitrate, ferric sulfate, ferric acetate and ferric citrate.
5. The method for producing lithium iron phosphate according to claim 1, characterized in that: in the step S2, the mol ratio of the soluble ferric salt accounts for 10-30% of the waste lithium iron phosphate.
6. The method for producing lithium iron phosphate according to claim 1, characterized in that: in the step S3, the phosphorus source is one or a combination of several of phosphoric acid, ammonium monohydrogen phosphate and ammonium dihydrogen phosphate.
7. The method for producing lithium iron phosphate according to claim 1, characterized in that: in the step S3, the molar ratio of the hydrogen peroxide to the phosphorus source is (1-1.5): 1, and the molar ratio of the phosphorus source to the iron is (1-1.1): 1.
8. The method for producing lithium iron phosphate according to claim 1, characterized in that: in step S4, the lithium source is one or a combination of several selected from lithium carbonate, lithium hydroxide, lithium nitrate and lithium acetate.
9. The method for producing lithium iron phosphate according to claim 1, characterized in that: in the step S4, the carbon source is one or a combination of more of glucose, white granulated sugar, sucrose, polyethylene glycol, citric acid, acetylene black, ketjen black, graphite and graphene.
10. The method for producing lithium iron phosphate according to claim 1, characterized in that: in the step S5, the calcining temperature is 650-800 ℃, and the calcining time is 5-15h.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101847763A (en) * | 2010-04-09 | 2010-09-29 | 奇瑞汽车股份有限公司 | Comprehensive recovering method of waste lithium iron phosphate battery |
| US20130216902A1 (en) * | 2010-04-21 | 2013-08-22 | Lg Chem, Ltd. | Carbon-coated lithium iron phosphate of olivine crystal structure and lithium secondary battery using the same |
| CN110127646A (en) * | 2019-06-17 | 2019-08-16 | 桑顿新能源科技(长沙)有限公司 | Lithium iron phosphate positive material and preparation method thereof and battery |
| US20220204355A1 (en) * | 2019-11-28 | 2022-06-30 | Contemporary Amperex Technology Co., Limited | Method for producing lithium iron phosphate precursor by using retired lithium iron phosphate battery as raw material |
| CN115020855A (en) * | 2022-06-24 | 2022-09-06 | 广东邦普循环科技有限公司 | Recycling method of waste lithium iron phosphate battery |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101847763A (en) * | 2010-04-09 | 2010-09-29 | 奇瑞汽车股份有限公司 | Comprehensive recovering method of waste lithium iron phosphate battery |
| US20130216902A1 (en) * | 2010-04-21 | 2013-08-22 | Lg Chem, Ltd. | Carbon-coated lithium iron phosphate of olivine crystal structure and lithium secondary battery using the same |
| CN110127646A (en) * | 2019-06-17 | 2019-08-16 | 桑顿新能源科技(长沙)有限公司 | Lithium iron phosphate positive material and preparation method thereof and battery |
| US20220204355A1 (en) * | 2019-11-28 | 2022-06-30 | Contemporary Amperex Technology Co., Limited | Method for producing lithium iron phosphate precursor by using retired lithium iron phosphate battery as raw material |
| CN115020855A (en) * | 2022-06-24 | 2022-09-06 | 广东邦普循环科技有限公司 | Recycling method of waste lithium iron phosphate battery |
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