Method for preparing lithium iron phosphate precursor for positive pole material of lithium-ion battery

A lithium-ion battery and cathode material technology, applied in battery electrodes, chemical instruments and methods, circuits, etc., can solve problems such as process duplication, environmental pollution, and cost increase

Inactive Publication Date: 2013-04-03
广西地博矿业集团股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Most of them are made from ores, from natural ores to chemically pure or analytically pure iron salts. Some doping elements that are beneficial to its electrochemical performance, most of these doping elements exist in natural minerals, resulting in duplication of processes and greatly incre

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0014] Example 1

[0015] First leach 100 grams of siderite with sulfuric acid, filter, and adjust the concentration of the solution so that its iron concentration is 0.5mol / L;

[0016] Step towards Add sufficient hydrogen peroxide solution (0.05mol / L) to the solution, then add phosphoric acid (1mol / L) equimolar to Fe, and then use 0.3mol / L sodium hydroxide solution to control the pH of the system at 2.5±0.1. React for 1 min in a stirred reactor at 95°C, wash, filter, and dry the obtained precipitate at 100°C to obtain a mixture of iron phosphate and doped phosphate, a precursor of lithium iron phosphate as a cathode material for lithium ion batteries. The lithium iron phosphate obtained by mixing and sintering the precursor and lithium carbonate has a specific discharge capacity of 161.4 mAh / g at 0.1C and a specific discharge capacity of 155.2 mAh / g at 1C.

Example Embodiment

[0017] Example 2

[0018] First leaching 100 grams of siderite with hydrochloric acid, filtering, and adjusting the concentration of the solution so that its iron concentration is 1mol / L;

[0019] Step towards Add enough ozone (2mol / L) to the solution, then add ammonium dihydrogen phosphate (0.2mol / L) equimolar to Fe, and use 1mol / L lithium hydroxide solution to control the pH of the system at 3.6±0.1, The reaction was carried out in a stirred reactor at 60°C for 48 hours, and the obtained precipitate was washed, filtered, and dried at 60°C to obtain a mixture of iron phosphate and doped phosphate, a precursor of lithium iron phosphate as a cathode material for lithium ion batteries. The lithium iron phosphate obtained by mixing and sintering the precursor and lithium carbonate has a specific discharge capacity of 153.4 mAh / g at 0.1C and a specific discharge capacity of 142.8 mAh / g at 1C.

Example Embodiment

[0020] Example 3

[0021] First leach 100 grams of siderite with sulfuric acid, filter, and adjust the concentration of the solution so that its iron concentration is 2mol / L;

[0022] Step towards Add sufficient hydrogen peroxide solution (0.05mol / L) to the solution, then add ammonium dihydrogen phosphate (3mol / L) equimolar to Fe, and then use 2mol / L ammonia to control the pH of the system at 4.5±0.1, at 25 The reaction was carried out in a stirred reactor at ℃ for 16 hours, and the obtained precipitate was washed, filtered, and dried at 300 ℃ to obtain a mixture of iron phosphate and doped phosphate, the precursor of lithium iron phosphate as the cathode material of lithium ion battery. The lithium iron phosphate obtained by mixing and sintering the precursor and lithium carbonate has a specific discharge capacity of 148.1 mAh / g at 0.1C and a specific discharge capacity of 135.7 mAh / g at 1C.

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Abstract

The invention discloses a method for preparing a lithium iron phosphate precursor for a positive pole material of a lithium-ion battery. According to the method, firstly siderite is subjected to leaching, the concentration of liquid is adjusted, then an oxidant and a precipitant are directly added without impurity removal, magnesium and manganese which are beneficial to the electrochemical properties of lithium iron phosphate in the siderite are enabled to be selectively subjected to precipitation through controlling synthesis conditions, and the lithium iron phosphate precursor is obtained after drying. As doped metal elements including magnesium and manganese are uniformly distributed in precursor particles in a phosphate form, re-doping is not required during the synthesis of the lithium iron phosphate, and the conductivity of the lithium iron phosphate can be greatly improved by the doped elements, so that the electrochemical properties of the lithium iron phosphate are greatly improved. According to the method, the source of raw materials is wide, the process flow is simple, the product quality is good and stable, and the cost is low, so that the method is particularly suitable for providing a high-quality iron source for the production of the lithium iron phosphate for the positive pole material of the lithium-ion battery; and meanwhile, siderite resources are comprehensively utilized, and huge economic and ecological benefits are inevitably brought to the society if scale production can be realized.

Description

technical field [0001] The invention belongs to the technical field of electrode materials, and in particular relates to a preparation method of a lithium iron phosphate precursor, a cathode material of a lithium ion battery. Background technique [0002] Lithium iron phosphate has become a very promising cathode material for lithium-ion batteries because of its high theoretical specific capacity, good cycle performance, good thermal stability, low price, and environmental friendliness. However, the large-scale industrial production of lithium iron phosphate is severely restricted due to the high cost, unstable quality, and low density of iron salt products, the main raw material for the production of lithium iron phosphate. [0003] At present, most of the iron sources for preparing lithium iron phosphate are chemically pure or analytically pure iron salts, mainly including ferrous oxalate, ferrous acetate, ferrous sulfate, ferric sulfate, ferric nitrate, ferric phosphate, ...

Claims

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Application Information

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IPC IPC(8): H01M4/58C01B25/45
CPCY02E60/10
Inventor 寇文胜陈国民李秀兰陈晓明李晓青孙文忠池上荣周若水李玉保蒙有言都安治刘恩义
Owner 广西地博矿业集团股份有限公司
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