Nanometer lithium iron phosphate with high capacity, high compaction density and high iron-phosphorus ratio, and preparation method of nanometer lithium iron phosphate

A lithium iron phosphate, high-pressure compaction technology, applied in the direction of nanotechnology, nanotechnology, nanotechnology, etc. for materials and surface science, to achieve the effect of facilitating insertion and extraction, uniform and fine particles, and improving grinding efficiency

Active Publication Date: 2021-11-30
湖北云翔聚能新能源科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, compared with the system energy density of ternary materials above 180Wh / kg, there is still a big gap
Moreover, whether it is gram capacity or compacted density, there is a certain room for improvement in lithium iron phosphate materials.

Method used

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  • Nanometer lithium iron phosphate with high capacity, high compaction density and high iron-phosphorus ratio, and preparation method of nanometer lithium iron phosphate
  • Nanometer lithium iron phosphate with high capacity, high compaction density and high iron-phosphorus ratio, and preparation method of nanometer lithium iron phosphate
  • Nanometer lithium iron phosphate with high capacity, high compaction density and high iron-phosphorus ratio, and preparation method of nanometer lithium iron phosphate

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preparation example Construction

[0036] According to a typical implementation of the embodiment of the present invention, a method for preparing nano-lithium iron phosphate with high capacity, high compacted density and high iron-phosphorus ratio is provided, such as Figure 4 As shown, the method includes:

[0037] Step S1, mixing the phosphorus salt solution and the iron salt solution to perform an oxidation reaction to obtain an oxidation slurry;

[0038] Step S2, performing the first grinding on the oxidized slurry to obtain oxidized slurry with fine particle size, and the oxidized slurry with fine particle size satisfies: D99≤1μm, D50≤300nm;

[0039] Step S3, after first washing the fine particle size slurry, adding pure water and phosphoric acid to carry out conversion reaction to obtain converted slurry;

[0040] Step S4, adjusting the pH of the converted slurry to 6-8, and then performing the second grinding to obtain the converted slurry with fine particle size, and the converted slurry with fine part...

Embodiment approach

[0058] The preparation method of described iron salt solution is: FeSO 4 or FeSO 4 7H 2 O is dissolved in pure water, and filtered to obtain the iron salt solution, in which FeSO 4 The concentration is 0.5~2mol / L;

[0059] The preparation method of the phosphorus salt solution is as follows: dissolving MAP or DAP in pure water, adjusting the pH to 6-8 with ammonia water or phosphoric acid, adding hydrogen peroxide and stirring evenly to obtain a phosphorus salt solution, and the P content in the phosphorus salt solution is 1~4mol / L, the substance concentration of hydrogen peroxide in the phosphorus salt solution is 0.55~0.65 times of P content;

[0060] In other embodiments, other methods may also be used to obtain the phosphorus salt solution and the iron salt solution.

[0061] As an optional implementation manner, in the step S3,

[0062] The first washing includes: filtering the fine particle size slurry and washing with pure water, and the end point of the washing i...

Embodiment 1

[0080] An embodiment of the present invention provides a method for preparing nano-lithium iron phosphate with high capacity, high compaction density and high iron-phosphorus ratio, the method comprising:

[0081]1. Preparation of anhydrous iron phosphate

[0082] Step S1, adding the phosphorus salt solution dropwise to the iron salt solution, the ratio of the amount of phosphorus to iron is (1-1.05):1, the stirring speed is 200rpm, and the reaction time is 0.5-3h to generate amorphous iron phosphate, and obtain Oxidized slurry; where,

[0083] Iron source preparation method is: FeSO 4 or FeSO 4 ·7H 2 O is dissolved in pure water, and filtered to obtain the iron salt solution, in which FeSO 4 The concentration is 0.5~2mol / L;

[0084] The preparation method of the phosphorus source is: dissolving MAP or DAP in pure water, adjusting the pH to 6-8 with ammonia water or phosphoric acid, adding hydrogen peroxide and stirring evenly to obtain a phosphorus salt solution, the con...

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Abstract

The invention provides nanometer lithium iron phosphate with high capacity, high compaction density and a high iron-phosphorus ratio, and a preparation method of nanometer lithium iron phosphate. The method comprises the following steps: mixing a phosphorus salt solution and an iron salt solution for an oxidation reaction to obtain oxidized slurry; performing primary grinding on the oxidized slurry to obtain fine-particle-size oxidized slurry with D99 of less than or equal to 1 [mu]m and D50 of less than or equal to 300 nm; carrying out primary washing on the fine-particle-size slurry, and then adding pure water and phosphoric acid for a conversion reaction so as to obtain converted slurry; adjusting the pH value of the conversion slurry to 6-8, and then performing secondary grinding to obtain fine-particle-size conversion slurry with D99 of less than or equal to 1 [mu]m and D50 of less than or equal to 300 nm; carrying out secondary washing and drying calcination to obtain anhydrous iron phosphate; and mixing the anhydrous iron phosphate with lithium carbonate, glucose and pure water, adding MoO3, graphite and carbon nanotubes, and then sequentially carrying out grinding, drying, sintering and crushing in an inert atmosphere to obtain the lithium iron phosphate material which has the advantages of high capacity, high compaction density and a high iron-phosphorus ratio.

Description

technical field [0001] The invention relates to the technical field of preparation of lithium iron phosphate, and more particularly relates to a nanometer lithium iron phosphate with high capacity, high compacted density and high iron-phosphorus ratio and a preparation method thereof. Background technique [0002] Lithium iron phosphate is currently one of the hottest positive electrode materials in the lithium battery industry. It has an orthorhombic olivine structure, and P and O are covalently bonded, making its structure extremely stable. Therefore, the lithium iron phosphate material has good cycle performance, and the cycle number can reach more than 2000 times; at the same time, it has good thermal stability and excellent safety performance. In addition, the lithium iron phosphate material does not contain precious metal elements. Both iron and phosphorus are conventional industrial raw materials, with low prices, abundant reserves, and low production costs. And it d...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/45C01G39/02C01B32/168C01B32/21B82Y40/00B82Y30/00H01M4/58
CPCC01B25/45C01G39/02C01B32/168C01B32/21B82Y40/00B82Y30/00H01M4/5825C01P2006/11C01P2006/40C01P2004/80Y02E60/10
Inventor 肖益帆陈迎迎
Owner 湖北云翔聚能新能源科技有限公司
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