CN108706564B - Preparation method of high-compaction lithium ion battery cathode material lithium iron phosphate - Google Patents

Preparation method of high-compaction lithium ion battery cathode material lithium iron phosphate Download PDF

Info

Publication number
CN108706564B
CN108706564B CN201810370248.5A CN201810370248A CN108706564B CN 108706564 B CN108706564 B CN 108706564B CN 201810370248 A CN201810370248 A CN 201810370248A CN 108706564 B CN108706564 B CN 108706564B
Authority
CN
China
Prior art keywords
lithium
iron phosphate
compaction
slurry
source
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201810370248.5A
Other languages
Chinese (zh)
Other versions
CN108706564A (en
Inventor
谢香兰
杨安臣
肖水龙
熊杜娟
罗邵滨
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
JIANGXI KINGLI TECHNOLOGY CO LTD
Original Assignee
JIANGXI KINGLI TECHNOLOGY CO LTD
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by JIANGXI KINGLI TECHNOLOGY CO LTD filed Critical JIANGXI KINGLI TECHNOLOGY CO LTD
Priority to CN201810370248.5A priority Critical patent/CN108706564B/en
Publication of CN108706564A publication Critical patent/CN108706564A/en
Application granted granted Critical
Publication of CN108706564B publication Critical patent/CN108706564B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

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
    • 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
    • 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)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Organic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

The invention provides a preparation method of high-compaction lithium ion battery anode material lithium iron phosphate, which comprises the following steps: s1, mixing a composite iron source, a phosphorus source and a carbon source which are composed of a lithium source, ferric orthophosphate and metal iron powder according to a certain proportion, putting the mixture into a dispersion kettle, adding a solvent for dispersion, coarse grinding and fine grinding to obtain uniformly mixed slurry, and performing spray drying on the slurry to obtain spherical precursor powder; s2, tabletting, granulating and densifying the obtained precursor powder to obtain a granular precursor; and S3, sintering the obtained granular precursor at high temperature under the protection of inert gas, naturally cooling to room temperature, and crushing to obtain the high-compaction lithium iron phosphate product. The invention adopts the composite iron source, the density of the metal iron powder is higher, and the nano ferric orthophosphate is matched, so that the synthesized lithium iron phosphate has excellent electrochemical performance and higher tap density; the precursor powder obtained by spray drying is tabletted, granulated and densified, so that the sintering production efficiency and the density of the lithium iron phosphate material are improved.

Description

Preparation method of high-compaction lithium ion battery cathode material lithium iron phosphate
Technical Field
The invention relates to the technical field of lithium ion battery materials, in particular to a preparation method of a high-compaction lithium ion battery anode material lithium iron phosphate.
Background
The new subsidy scheme of the new energy automobile takes the energy density of a battery system as a subsidy standard, and particularly the subsidy of the new energy passenger car has larger performance grade difference of power batteries. Although the energy density of a lithium iron phosphate monomer battery cell of a plurality of battery enterprises at present can be about 140wh/kg, the energy density of a battery system after being grouped is mostly not more than 120 wh/kg. This means that most of the reported vehicle models can only obtain the minimum grade subsidy standard, thereby seriously attacking the enthusiasm of the vehicle enterprises to develop pure electric motor coaches. This requires the positive electrode material enterprises to develop higher performance lithium iron phosphate materials.
The compaction density is the ratio of the density of the area coated with the material of the battery pole piece to the thickness of the material after pole piece compaction. The lithium ion power battery is manufacturedIn the process, the compaction density has a large influence on the battery performance. Generally, the higher the compaction density, the higher the capacity of the battery of the same specification can be made, so the compaction density is also taken as one of the reference indexes of the energy density of the material. Under the conditions of fixed specification and model of the battery and fixed process conditions, the higher the compaction density is, the higher the capacity of the single battery is, and the lower the unit comprehensive cost of the battery is. However, the compaction density of the common lithium iron phosphate material is low and can only reach 2.3-2.35 g/cm3Left and right. If the compaction density of the lithium iron phosphate material can be greatly improved, the specific energy of the lithium iron phosphate battery can be greatly improved.
Chinese patent application No. CN106744780A discloses a method for preparing lithium iron phosphate as a high-compaction lithium ion battery positive electrode material, which comprises the following steps: (1) firstly mixing a lithium source, a high-compaction iron source, a phosphorus source and a solvent, then adding a doped metal oxide and a dispersing agent for continuous mixing, finally adding a carbon source for mixing, and dispersing and drying the uniformly mixed slurry to obtain solid powder particles; (2) carrying out jet milling on solid powder particles; (3) and (3) putting the crushed material into a rotary furnace with inert gas protection for heat treatment, after the material is naturally cooled, transferring the material into a high-temperature sintering furnace with inert gas protection for high-temperature heat treatment, and then naturally cooling, sieving and classifying by air flow to obtain the high-compaction-density lithium iron phosphate. The application of the invention is described as follows: the method is simple in process and capable of obviously improving the compaction density of the lithium iron phosphate anode material, but the phosphorus source adopted by the method is ammonium-containing salts, a large amount of ammonia gas is generated in the synthesis process, a large amount of waste gas treatment cost is required to be invested, and the environment is polluted.
Disclosure of Invention
The invention aims to solve the technical problems and provides a preparation method of a lithium iron phosphate material which is simple in process, suitable for industrial production, environment-friendly, high in compaction and excellent in performance. The invention adopts the following technical scheme:
a preparation method of lithium iron phosphate used as a high-compaction lithium ion battery anode material comprises the following steps:
s1, mixing a composite iron source, a phosphorus source and a carbon source which are composed of a lithium source, ferric orthophosphate and metal iron powder according to a certain proportion, then putting the mixture into a dispersion kettle, adding a solvent serving as a dispersing agent to perform dispersion, coarse grinding and fine grinding to obtain uniformly mixed slurry, and performing spray drying on the slurry to obtain spherical precursor powder;
s2, tabletting, granulating and densifying the obtained precursor powder, namely crushing the spherical precursor powder obtained by spray drying to obtain a granular precursor;
and S3, sintering the obtained granular precursor at high temperature under the protection of inert gas, naturally cooling to room temperature, and crushing to obtain the high-compaction lithium iron phosphate product.
The invention adopts the composite iron source consisting of ferric orthophosphate and metallic iron powder, the metallic iron powder has higher density, the lithium iron phosphate synthesized by the composite iron source has higher tap density compared with other raw materials, the density of the lithium iron phosphate material is improved, and the excellent electrochemical performance can be obtained by matching the ferric orthophosphate; the precursor powder is tabletted, granulated and densified, so that the mass transfer and heat transfer rates in the material sintering process are improved, the processing performance is excellent, and the compaction density is high; the slurry grinding comprises two steps of coarse grinding and fine grinding, so that the grinding efficiency is improved, the slurry is mixed more uniformly, the slurry granularity is small and easy to control, and a high-compaction product is obtained.
Further, the composite iron source adopts a mixture of micron-sized metal iron powder and nanoscale ferric orthophosphate; the lithium iron phosphate material has excellent electrochemical performance, and meanwhile, the density of the lithium iron phosphate material can be further improved due to the gradation of the metal iron powder with particles and ferric orthophosphate;
preferably, the composite iron source is a mixture of D50 ═ 1-2 um metal iron powder prepared by a reduction method and ferric orthophosphate with primary particles of 50-200 nm.
Further, in the burden in step S1, Li: fe: the molar ratio of P is (0.9-1.2): 1: (0.8-1.0), wherein the carbon source accounts for 3-15% of the mixture by weight;
further, the mixing molar ratio of the metal iron powder to the ferric orthophosphate in the composite iron source is 1: 1-1: the lithium iron phosphate material obtained in the grain composition range has high density, and preferably, the mixing molar ratio is 1: 2-1: 5.
further, step S1 further includes at least one of the following technical features:
the lithium source comprises any one or a mixture of more than two of lithium hydroxide, lithium carbonate, lithium nitrate, lithium oxalate, lithium dihydrogen phosphate, lithium citrate and lithium acetate;
the phosphorus source comprises any one or a mixture of more than two of ferric phosphate, lithium dihydrogen phosphate and phosphoric acid;
the carbon source adopts one or more of glucose, polyvinyl alcohol, sucrose, PVP, polyethylene glycol, phenolic resin, hexamethylenetetramine and citric acid;
the solvent is ethanol, isopropanol, acetone or deionized water.
Further, in the step S1, the adding amount of the solvent is 20% -60% of the solid content of the slurry, and the dispersing time is 1-3 h;
further, in step S1, the coarse grinding time is 1-5 h, and the particle size D50 of the slurry after coarse grinding is controlled to be 1-2 um;
further, in step S1, the fine grinding time is 2-6 h, and the particle size D50 of the slurry after the fine grinding is controlled to be 400-800 nm.
Further, in the step S1, the air inlet temperature is 200-300 ℃, and the air outlet temperature is 50-100 ℃.
Further, the pressure used for tabletting and granulating in the step S2 is 10-100 MPa;
further, the temperature of the high-temperature sintering in the step S3 is 700-800 ℃, and the sintering time is 6-12 h.
Further, in the step S3, the inert atmosphere is one or more of nitrogen, helium, neon and argon, and the high-compaction lithium iron phosphate product is obtained by jet milling or mechanical milling.
Further, the granularity D50 of the high-compaction lithium iron phosphate product obtained in the step S3 is controlled to be 2-5 um, the granularity D90 of the high-compaction lithium iron phosphate product is controlled to be not more than 12um, the granularity of the product is reasonable in composition, the filling of pores is realized through the size and granularity level matching, and the compaction density of the lithium iron phosphate material is improved; the carbon content is controlled to be 1.4 +/-0.5 wt%, the carbon content can influence the specific surface area and the conductivity of the lithium iron phosphate material, the specific surface area of the material is increased due to excessively high carbon content, particles are easy to agglomerate together, and the conductivity of the material is poor due to excessively low carbon content.
The invention has the following beneficial effects:
(1) according to the invention, D50 ═ 1-2 um metal iron powder (the purity is more than or equal to 98.5%) is mixed with ferric orthophosphate with primary particles of 50-200 nm in proportion to form a composite iron source, the metal iron powder has higher density, the lithium iron phosphate synthesized by the metal iron powder has higher tap density compared with other raw materials, and the lithium iron phosphate is matched with nanoscale ferric orthophosphate, so that the composite iron source has excellent electrochemical performance, and meanwhile, the density of the lithium iron phosphate material can be further improved due to the grading of large and small particles;
(2) the method carries out tabletting, granulation and densification on precursor powder, and crushes hollow spherical powder obtained by spray drying to obtain a granular precursor, thereby solving the problems of poor processability, low compaction density and the like caused by hollow spheres; the mass transfer and heat transfer rates in the material sintering process are improved, the materials in batches are uniform, and the processing performance is excellent; the problems of low powder density and low sintering production efficiency are solved;
(3) the slurry grinding method comprises two steps of coarse grinding and fine grinding, improves the grinding efficiency, enables the slurry to be mixed more uniformly, has small slurry granularity and is easy to control, and is beneficial to obtaining a high-compaction product;
(4) the product has reasonable granularity composition, realizes the filling of pores by matching the granularity of the product and improves the compaction density of the lithium iron phosphate material; the carbon content is controlled to be 1.4 +/-0.5 wt%, and the conductivity and the specific surface area of the material are both considered;
(5) the method provided by the invention has the advantages of short flow, simple and environment-friendly process and mild reaction conditions, and is suitable for industrial production.
Drawings
FIG. 1 is a schematic flow diagram of the process of the present invention;
FIG. 2 is an SEM photograph of the lithium iron phosphate powder prepared in example 1;
FIG. 3 is an SEM photograph of the lithium iron phosphate powder prepared in example 2;
FIG. 4 is an SEM photograph of the lithium iron phosphate powder prepared in example 3;
FIG. 5 is an SEM photograph of the lithium iron phosphate powder prepared in example 4;
FIG. 6 is an SEM photograph of the lithium iron phosphate powder prepared in example 5;
FIG. 7 is an SEM photograph of the lithium iron phosphate powder prepared in comparative example 1;
FIG. 8 is an SEM photograph of the lithium iron phosphate powder prepared in comparative example 2;
fig. 9 is an SEM image of the lithium iron phosphate powder prepared in comparative example 3.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in 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 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.
Example 1:
lithium carbonate (Li)2CO3)63.36 kg of ferric orthophosphate (FePO) with primary particle size of 50-200 nm4)250.00 kg of lithium dihydrogen phosphate (LiH)2PO4)18.79 kg of metal iron powder with the particle size of D50 ═ 2um of 10.24 kg, 19.00 kg of glucose and 11.00 kg of polyethylene glycol are placed in a dispersing kettle, 630L of deionized water is added for dispersing, the dispersion time of the slurry is 1h, coarse grinding is carried out, the coarse grinding time is 3h, the particle size D50 of the slurry after coarse grinding is controlled to be 1-2 um, finally fine grinding is carried out, the fine grinding time is 4h, and the particle size D50 of the slurry after fine grinding is controlled to be 500nm, so that the homogeneous mixed slurry is obtained.
Then, carrying out spray drying on the obtained uniformly mixed slurry, wherein the air inlet temperature of the spray drying is controlled at 240 ℃, the air outlet temperature is controlled at 90 ℃, and spherical precursor powder is obtained; then tabletting, granulating and densifying the precursor powder, wherein the pressure for tabletting and granulating is 70MPa, and obtaining the granular precursor.
Sintering the granular precursor in a kiln with protective atmosphere nitrogen at 770 ℃ for 8 hours, naturally cooling to room temperature, and crushing to obtain high-compaction lithium iron phosphate powder with the compaction density of 2.80g/cm3. The SEM microscopic morphology of the product is shown in figure 2, the surface of the material is round and smooth, the carbon coating is uniform, the particle size distribution is uniform, and the subsequent processing performance of the material is favorably improved.
Example 2:
lithium carbonate (Li)2CO3)50.69 kg of ferric orthophosphate (FePO) with primary particle of 50-100 nm4)200.00 kg of lithium dihydrogen phosphate (LiH)2PO4)57.96 kg of metal iron powder (purity is more than or equal to 98.5%) 31.59 kg of D50 ═ 1um, 18.5 kg of glucose and 9.50 kg of water-soluble phenolic resin are placed in a dispersion kettle, then 550L of deionized water is added for dispersion, the slurry dispersion time is 2h, then coarse grinding is carried out, the coarse grinding time is 1h, the slurry granularity D50 after coarse grinding is controlled to be 1-1.5 um, finally fine grinding is carried out, the fine grinding time is 6h, and the slurry granularity D50 after fine grinding is controlled to be 400nm, so that the homogeneous mixed slurry is obtained.
Then, carrying out spray drying on the obtained uniformly mixed slurry, wherein the air inlet temperature of the spray drying is controlled to be 280 ℃, and the air outlet temperature is controlled to be 100 ℃ to obtain spherical precursor powder; then tabletting, granulating and densifying the precursor powder, wherein the pressure for tabletting and granulating is 50MPa, and obtaining the granular precursor.
And (3) placing the granular precursor into a kiln with protective atmosphere argon gas for sintering, wherein the sintering temperature is 750 ℃, the sintering time is 10 hours, naturally cooling to room temperature, and crushing to obtain high-compaction lithium iron phosphate powder, wherein the product granularity D50 is controlled to be 3um, and the product granularity D90 is controlled to be 10 um. The resulting product had a compacted density of 2.95g/cm3. The SEM microscopic morphology of the product is shown in figure 3, the surface of the material is round and smooth, the carbon coating is uniform, the particle size distribution is uniform, and the subsequent processing performance of the material is favorably improved.
Example 3:
lithium carbonate (Li)2CO3)38.02 kg of ferric orthophosphate (FePO) with primary particle size of 50-150 nm4)150.00 kg, lithium dihydrogen phosphate (LiH)2PO4)55.30 kg of metal iron powder (with the purity being more than or equal to 98.5%) with the particle size of 101.44 kg and the particle size of D50 ═ 1.5um, 19.00 kg of cane sugar, 5.00 kg of polyvinyl alcohol and 6.00 kg of PVP are placed in a dispersing kettle, then 520L of ethanol is added for dispersing, the dispersion time of the slurry is 2h, then coarse grinding is carried out, the coarse grinding time is 3h, the particle size D50 of the slurry after coarse grinding is controlled to be 1.2-2 um, finally fine grinding is carried out, the fine grinding time is 5h, and the particle size D50 of the slurry after fine grinding is controlled to be 600nm, so that the homogeneous mixed slurry is obtained.
Then, spray drying is carried out on the obtained evenly mixed slurry, the air inlet temperature of the spray drying is controlled at 220 ℃, and the air outlet temperature is controlled at 70 ℃ to obtain spherical precursor powder; then tabletting, granulating and densifying the precursor powder, wherein the pressure for tabletting and granulating is 80MPa, and obtaining the granular precursor.
And (2) placing the granular precursor into a furnace with neon gas in protective atmosphere for sintering, wherein the sintering temperature is 720 ℃, the sintering time is 12 hours, naturally cooling to room temperature, and carrying out jet milling to obtain high-compaction lithium iron phosphate powder, wherein the product granularity D50 is controlled to be 2um, and the product granularity D90 is controlled to be 12 um. The resulting product had a compacted density of 2.84g/cm3. The SEM microscopic morphology of the product is shown in figure 4, the surface of the material is round and smooth, the carbon coating is uniform, the particle size distribution is uniform, and the subsequent processing performance of the material is favorably improved.
Example 4:
mixing lithium acetate (CH)3COOLi)121.42 kg of ferric orthophosphate (FePO) with primary particle size of 100-200 nm4)230.00 kg of metal iron powder with the particle size D50 being 1um and 17.10 kg of metal iron powder, 25.00 kg of polyethylene glycol, 5.00 kg of hexamethylenetetramine and 12.00 kg of citric acid are placed in a dispersing kettle, then 500L of isopropanol is added for dispersing, the dispersion time of the slurry is 3h, then coarse grinding is carried out, the coarse grinding time is 4h, the particle size D50 of the slurry after coarse grinding is controlled to be 1um, finally fine grinding is carried out, the fine grinding time is 3h, and the particle size D50 of the slurry after fine grinding is controlled to be 700nm, so that the homogeneous mixed slurry is obtained.
Then, carrying out spray drying on the obtained uniformly mixed slurry, wherein the air inlet temperature of the spray drying is controlled at 200 ℃, and the air outlet temperature is controlled at 60 ℃ to obtain spherical precursor powder; then tabletting, granulating and densifying the precursor powder, wherein the pressure used for tabletting and granulating is 30MPa, and obtaining the granular precursor.
And (2) placing the granular precursor into a furnace with helium in protective atmosphere for sintering, wherein the sintering temperature is 800 ℃, the sintering time is 6 hours, naturally cooling to room temperature, and mechanically crushing to obtain high-compaction lithium iron phosphate powder, wherein the product granularity D50 is controlled to be 3um, and the product granularity D90 is controlled to be 8 um. The resulting product had a compacted density of 2.86g/cm3. The SEM microscopic morphology of the product is shown in figure 5, the surface of the material is round and smooth, the carbon coating is uniform, the particle size distribution is uniform, and the subsequent processing performance of the material is favorably improved.
Example 5:
65.70 kg of lithium hydroxide (LiOH) and lithium nitrate (LiNO)3)72.54 kg of ferric orthophosphate (FePO) with primary particle size of 100-150 nm4)350.00 kg of phosphoric acid (H)3PO4)76.74 kg of metal iron powder (the purity is more than or equal to 98.5%) 63.18 kg of D50 ═ 1.8um, 25.00 kg of polyvinyl alcohol and 10.00 kg of water-soluble phenolic resin are placed in a dispersing kettle, then acetone 1100L is added for dispersing, the slurry dispersing time is 1h, then coarse grinding is carried out, the coarse grinding time is 5h, the slurry granularity D50 after coarse grinding is controlled to be 2um, finally fine grinding is carried out, the fine grinding time is 2h, and the slurry granularity D50 after fine grinding is controlled to be 800nm, so that the homogeneous mixed slurry is obtained.
Then, carrying out spray drying on the obtained uniformly mixed slurry, wherein the air inlet temperature of the spray drying is controlled at 210 ℃, and the air outlet temperature is controlled at 55 ℃ to obtain spherical precursor powder; then tabletting, granulating and densifying the precursor powder, wherein the pressure used for tabletting and granulating is 100MPa, and obtaining the granular precursor.
And (3) placing the granular precursor into a kiln with protective atmosphere nitrogen for sintering, wherein the sintering temperature is 760 ℃, the sintering time is 9 hours, naturally cooling to room temperature, and carrying out jet milling to obtain high-compaction lithium iron phosphate powder, wherein the product granularity D50 is controlled to be 5um, and the product granularity D90 is controlled to be 12 um. The resulting product had a compacted density of 2.91g/cm3. S of the productThe EM microscopic morphology is shown in figure 6, the surface of the material is round and smooth, the carbon coating is uniform, the particle size distribution is uniform, and the subsequent processing performance of the material is improved.
Comparative example 1:
lithium carbonate (Li)2CO3)63.36 kg of ferric orthophosphate (FePO)4)250.00 kg of slurry, 20.00 kg of glucose and 7.50 kg of polyethylene glycol are placed in a dispersion kettle, then 630L of deionized water is added for dispersion, coarse grinding and fine grinding, the slurry dispersion time is 1h, the coarse grinding time is 3h, the slurry granularity D50 after coarse grinding is controlled to be 1-2 um, the fine grinding time is 4h, and the slurry granularity D50 after fine grinding is controlled to be 500nm, so that the homogeneous mixed slurry is obtained.
Then, carrying out spray drying on the obtained uniformly mixed slurry, wherein the air inlet temperature of the spray drying is controlled at 240 ℃, and the air outlet temperature is controlled at 90 ℃ to obtain spherical precursor powder; then tabletting, granulating and densifying the precursor powder, wherein the pressure for tabletting and granulating is 70MPa, and obtaining the granular precursor.
Sintering the granular precursor in a kiln with protective atmosphere nitrogen at 770 ℃ for 8 hours, naturally cooling to room temperature, and crushing to obtain high-compaction lithium iron phosphate powder with the compaction density of 2.56g/cm3. The SEM microscopic morphology of the product is shown in figure 7, no metal iron powder is added into an iron source, the obtained material has more surface edges and corners, uneven particle size distribution and larger range, the subsequent processing performance of the material is general, and the compacted density is lower.
Comparative example 2:
lithium carbonate (Li)2CO3)63.36 kg of ferric orthophosphate (FePO)4)250.00 kg of slurry, 20.00 kg of glucose and 7.50 kg of polyethylene glycol are placed in a dispersion kettle, then 630L of deionized water is added for dispersion, coarse grinding and fine grinding, the slurry dispersion time is 1h, the coarse grinding time is 3h, the slurry granularity D50 after coarse grinding is controlled to be 1-2 um, the fine grinding time is 4h, and the slurry granularity D50 after fine grinding is controlled to be 500nm, so that the homogeneous mixed slurry is obtained.
And then carrying out spray drying on the obtained uniformly mixed slurry, wherein the air inlet temperature of the spray drying is controlled at 240 ℃, and the air outlet temperature is controlled at 90 ℃ to obtain spherical precursor powder.
Placing the spherical precursor into a kiln with protective atmosphere nitrogen for sintering at 770 ℃ for 8 hours, naturally cooling to room temperature, and crushing to obtain lithium iron phosphate powder with the compaction density of 2.30g/cm3. The SEM microscopic morphology of the product is shown in figure 8, no metal iron powder is added into an iron source, tabletting and granulation are not carried out, the obtained material has more rough edges and corners on the surface, serious agglomeration phenomenon, uneven particle size distribution and larger range, the subsequent processing performance of the material is general, and the compaction density is low.
Comparative example 3:
lithium carbonate (Li)2CO3)63.36 kg of ferric orthophosphate (FePO)4)250.00 kg of metal iron powder of 2um of 10.24 kg, 20.00 kg of glucose and 7.50 kg of polyethylene glycol are placed in a dispersion kettle, then 630L of deionized water is added for dispersion, coarse grinding and fine grinding, the dispersion time of the slurry is 1h, the coarse grinding time is 3h, the granularity D50 of the slurry after the coarse grinding is controlled to be 1-2 um, the fine grinding time is 4h, and the granularity D50 of the slurry after the fine grinding is controlled to be 500nm, so that the homogeneous mixed slurry is obtained.
And then carrying out spray drying on the obtained uniformly mixed slurry, wherein the air inlet temperature of the spray drying is controlled at 240 ℃, and the air outlet temperature is controlled at 90 ℃ to obtain spherical precursor powder.
Placing the spherical precursor into a kiln with protective atmosphere nitrogen for sintering at 770 ℃ for 8 hours, naturally cooling to room temperature, and crushing to obtain lithium iron phosphate powder with the compaction density of 2.49g/cm3. The SEM microscopic morphology of the product is shown in figure 9, tabletting and granulation are not carried out in the preparation process, the surface of the obtained material is rough, the particle size distribution is uneven, the subsequent processing performance of the material is general, and the compaction density is low.
The tap density, the compacted density, the carbon content and the electrochemical properties of the products obtained in the above examples and comparative examples were compared.
Wherein, the electrochemical performance test is as follows:
the lithium iron phosphate powder materials prepared in examples 1 to 5 and comparative examples 1 to 3 were subjected to charge and discharge tests under the following half-cell test conditions:
the test of the cell was carried out at room temperature (25 ℃) and the positive electrode sheet was prepared as follows: NMP (N-2-methyl pyrrolidone) is used as a solvent and a dispersing agent, 80% (mass ratio) of the prepared lithium iron phosphate powder positive electrode material, 10% of super P (super conductive carbon black) and 10% of an adhesive (polyvinylidene fluoride and PVDF) are uniformly mixed to prepare slurry, the solid content of the slurry is 45%, then the slurry is coated on an aluminum foil with the thickness of 20 mu m to prepare a film, and the film is dried in vacuum at 120 ℃ and then punched into a 10mm sheet to prepare a positive electrode sheet. In a glove box filled with high-purity argon, a metal lithium sheet is used as a negative electrode, a Celgard 2400 membrane (a commercially available membrane) is used as a membrane, and an electrolyte is 1mol/L LiPF6(EC + DME), and a simulated cell was assembled and subjected to charge/discharge test.
Comparative data are shown in table 1:
TABLE 1 comparison of Experimental data
Figure BDA0001638231870000101
Figure BDA0001638231870000111
As can be seen from the data in the table, the tap density and the compacted density of the lithium iron phosphate material prepared by the method are obviously improved on the basis of ensuring the capacitance.
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments or portions thereof without departing from the spirit and scope of the invention.

Claims (8)

1. A preparation method of lithium iron phosphate used as a high-compaction lithium ion battery anode material is characterized by comprising the following steps:
s1, mixing a composite iron source, a phosphorus source and a carbon source which are composed of a lithium source, ferric orthophosphate and metal iron powder according to a certain proportion, then putting the mixture into a dispersion kettle, adding a solvent serving as a dispersing agent to perform dispersion, coarse grinding and fine grinding to obtain uniformly mixed slurry, and performing spray drying on the slurry to obtain spherical precursor powder; the composite iron source is a mixture of metal iron powder with the diameter of D50 being 1-2 mu m and ferric orthophosphate with primary particles being 50-200 nm, wherein the mixing molar ratio of the metal iron powder to the ferric orthophosphate is 1: 1-1: 10; the adding amount of the solvent is 20-60% of the solid content of the slurry, and the dispersion time is 1-3 h; the coarse grinding time is 1-5 h, and the granularity D50 of the slurry after coarse grinding is controlled to be 1-2 mu m; the fine grinding time is 2-6 h, and the granularity D50 of the slurry after fine grinding is controlled to be 400-800 nm;
s2, tabletting, granulating and densifying the obtained precursor powder to obtain a granular precursor;
and S3, sintering the obtained granular precursor at high temperature under the protection of inert gas, naturally cooling to room temperature, and crushing to obtain the high-compaction lithium iron phosphate product.
2. The method for preparing lithium iron phosphate as a cathode material of a high-compaction lithium ion battery according to claim 1, wherein in the ingredients in step S1, Li: fe: the molar ratio of P is (0.9-1.2): 1: (0.8-1.0), and the carbon source accounts for 3-15% of the mixture by weight.
3. The method for preparing the lithium iron phosphate as the cathode material of the high-compaction lithium ion battery according to claim 2, wherein the mixing molar ratio of the metal iron powder and the iron orthophosphate in the composite iron source is 1: 2-1: 5.
4. the method for preparing the lithium iron phosphate as the positive electrode material of the high-compaction lithium ion battery according to any one of claims 1 to 3, wherein the step S1 further comprises at least one of the following technical features:
the lithium source comprises any one or a mixture of more than two of lithium hydroxide, lithium carbonate, lithium nitrate, lithium oxalate, lithium dihydrogen phosphate, lithium citrate and lithium acetate;
the phosphorus source comprises any one or a mixture of more than two of ferric phosphate, lithium dihydrogen phosphate and phosphoric acid;
the carbon source adopts one or more of glucose, polyvinyl alcohol, sucrose, PVP, polyethylene glycol, phenolic resin, hexamethylenetetramine and citric acid;
the solvent is ethanol, isopropanol, acetone or deionized water.
5. The method for preparing lithium iron phosphate as the cathode material of a high-compaction lithium ion battery of claim 4, wherein the spray drying is performed in step S1, the air inlet temperature is 200 ℃ to 300 ℃, and the air outlet temperature is 50 ℃ to 100 ℃.
6. The method for preparing the lithium iron phosphate as the cathode material of the high-compaction lithium ion battery of claim 5, wherein the pressure for tabletting and granulating in step S2 is 10-100 MPa; in the step S3, the high-temperature sintering temperature is 700-800 ℃, and the sintering time is 6-12 hours.
7. The method for preparing lithium iron phosphate as the cathode material of a high-compaction lithium ion battery of claim 6, wherein the inert atmosphere in step S3 is one or more of nitrogen, helium, neon and argon, and the high-compaction lithium iron phosphate product is obtained by jet milling or mechanical milling.
8. The method for preparing lithium iron phosphate as the cathode material of the high-compaction lithium ion battery of claim 7, wherein the particle size D50 of the high-compaction lithium iron phosphate product obtained in the step S3 is controlled to be 2-5 μm, the particle size D90 is controlled to be not more than 12 μm, and the carbon content is controlled to be 1.4 +/-0.5 wt%.
CN201810370248.5A 2018-04-24 2018-04-24 Preparation method of high-compaction lithium ion battery cathode material lithium iron phosphate Active CN108706564B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201810370248.5A CN108706564B (en) 2018-04-24 2018-04-24 Preparation method of high-compaction lithium ion battery cathode material lithium iron phosphate

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201810370248.5A CN108706564B (en) 2018-04-24 2018-04-24 Preparation method of high-compaction lithium ion battery cathode material lithium iron phosphate

Publications (2)

Publication Number Publication Date
CN108706564A CN108706564A (en) 2018-10-26
CN108706564B true CN108706564B (en) 2020-11-24

Family

ID=63866931

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201810370248.5A Active CN108706564B (en) 2018-04-24 2018-04-24 Preparation method of high-compaction lithium ion battery cathode material lithium iron phosphate

Country Status (1)

Country Link
CN (1) CN108706564B (en)

Families Citing this family (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109585809B (en) * 2018-11-08 2021-09-10 山东精工电子科技有限公司 Lithium iron phosphate material with rough surface and preparation method thereof
CN109650366A (en) * 2018-11-22 2019-04-19 湖北融通高科先进材料有限公司 A kind of LiFePO4 and preparation method thereof
CN111217347A (en) * 2018-11-23 2020-06-02 深圳市贝特瑞纳米科技有限公司 High-compaction lithium iron phosphate material and preparation method thereof
CN111422850A (en) * 2019-08-22 2020-07-17 山东精工电子科技有限公司 Method for preparing lithium iron phosphate anode material with adjustable granularity
CN110745802A (en) * 2019-10-14 2020-02-04 重庆特瑞电池材料股份有限公司 Method for preparing lithium iron phosphate by electromagnetic induction self-heating
CN112768688B (en) * 2019-11-05 2023-06-06 贝特瑞（天津）纳米材料制造有限公司 Lithium iron phosphate material, preparation method thereof and lithium ion battery
CN112723333A (en) * 2020-12-11 2021-04-30 江苏锂源电池材料有限公司 Method for improving low-temperature performance and compaction density of lithium iron phosphate
CN114162800B (en) * 2021-11-15 2022-11-29 广东派勒智能纳米科技股份有限公司 Production method of lithium ion battery anode material
CN114368737A (en) * 2022-02-23 2022-04-19 东莞市创明电池技术有限公司 High-compaction and high-capacity lithium iron phosphate positive electrode material and preparation method and application thereof
CN114725318B (en) * 2022-04-15 2023-11-10 湖北万润新能源科技股份有限公司 High-magnification lithium iron phosphate positive electrode material, preparation method thereof, positive electrode and battery
CN114804058A (en) * 2022-05-27 2022-07-29 湖北万润新能源科技股份有限公司 High-tap-density lithium iron phosphate cathode material and preparation method and application thereof
CN115072694A (en) * 2022-06-28 2022-09-20 衢州华友钴新材料有限公司 Lithium iron phosphate anode material, preparation method thereof and lithium ion battery
CN115650200A (en) * 2022-12-06 2023-01-31 广州天赐高新材料股份有限公司 Preparation method of high-energy-density lithium iron phosphate material

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101591012B (en) * 2008-05-27 2012-06-13 北京有色金属研究总院 Preparation method of lithium iron phosphate as cathode material of lithium ion battery
CN101519198A (en) * 2009-04-16 2009-09-02 丁建民 Method for preparing cathode material of lithium iron phosphate
CN107256968A (en) * 2017-06-19 2017-10-17 贝特瑞（天津）纳米材料制造有限公司 A kind of high compacted density LiFePO4 and preparation method thereof

Also Published As

Publication number Publication date
CN108706564A (en) 2018-10-26

Similar Documents

Publication Publication Date Title
CN108706564B (en) Preparation method of high-compaction lithium ion battery cathode material lithium iron phosphate
CN107785560B (en) High-performance silicon-carbon negative electrode material and preparation method thereof
KR20210059771A (en) Silicon oxide/carbon composite anode material, manufacturing method thereof, and lithium ion battery
CN107910498B (en) Modified lithium titanate negative electrode material, preparation method and lithium titanate battery
TW201335067A (en) Electrode material, electrode board and lithium ion battery, and method of manufacturing electrode material and electrode board
CN102148374A (en) Method for adopting spray pyrolysis technology to prepare spherical anode material lithium iron phosphate
CN109167028B (en) Regeneration preparation method of lithium iron phosphate/carbon composite material
CN102623705B (en) Lithium ion battery cathode material LiFePO4/C, and preparation method and application thereof
CN113903896B (en) Secondary particle hard carbon composite material and preparation method and application thereof
CN113072051B (en) Post-treatment method of phosphate system anode material
US20230420660A1 (en) Silicon-based anode material and preparation method thereof
CN104319380A (en) Composite LiFePO4/C cathode material for lithium ion battery and preparation method for composite LiFePO4/C cathode material
CN108682853B (en) Preparation method of lithium iron phosphate and lithium iron phosphate cathode material prepared by same
JP2013191516A (en) Positive electrode material for lithium ion battery, positive electrode for lithium ion battery, and lithium ion battery
CN115072694A (en) Lithium iron phosphate anode material, preparation method thereof and lithium ion battery
CN117133913A (en) Lithium iron phosphate precursor, lithium iron phosphate material, and preparation methods and applications thereof
CN116936767A (en) Preparation method of high-capacity water system processed lithium iron phosphate anode
JP2011216233A (en) Electrode material and film
CN116565180A (en) High tap density lithium iron phosphate positive electrode material, and preparation method and application thereof
CN116723998A (en) Lithium iron manganese phosphate positive electrode material and preparation method and application thereof
CN116053437A (en) Activated carbon layer coated silicon-oxygen-based negative electrode material, preparation method and application thereof
CN111313011B (en) Preparation method of low-cost high-performance lithium iron phosphate
CN101728518B (en) Preparation method of positive electrode material LiFePO4/C of secondary lithium battery
CN111099570B (en) Improve LiFePO 4 Method for compacting density, products obtained and uses
CN108529584B (en) Preparation method of high-density lithium iron phosphate cathode material

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