High-density spherical iron phosphate and manufacture method thereof

An iron phosphate, high-density technology, applied in chemical instruments and methods, phosphorus compounds, inorganic chemistry, etc., can solve problems such as hindering the practical application of lithium iron phosphate, poor high-rate charge and discharge performance, and low volume specific capacity. The effect of normal intercalation/deintercalation channels, few steps and high purity

Inactive Publication Date: 2008-09-24
GUANGZHOU RONGJIE MATERIAL TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] However, lithium iron phosphate has two obvious disadvantages, one is low conductivity, resulting in poor high-rate charge and discharge performance and low actual s

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Use deionized water to make ferric chloride into 3mol, ammonium citrate into 2mol mixed solution, use deionized water to make diammonium hydrogen phosphate into 3mol, sodium hydroxide into 1mol mixed solution, open the reaction vessel Stir, put 1 / 3 volume of deionized water in the container, and heat the bottom water to 40°C, add ferric chloride into the reaction container at a flow rate of 5-15ml / min, diammonium hydrogen phosphate at a flow rate of 5-15ml / min The flow rate is added to the reaction vessel, and the pH value is controlled to be 3.0±0.8 by adjusting the flow rate of diammonium hydrogen phosphate. The precipitate suspension generated by the reaction overflows into another container for aging. After aging for 6 hours, the precipitate is washed Clean until the pH of the washing water is greater than 6.8, then filter, and bake the filter cake in an oven at 100-120°C for 4-15 hours to obtain high-density spherical iron phosphate.

Embodiment 2

[0025] Use deionized water to make ferric sulfate into 2mol, ammonium citrate into 1mol mixed solution, use deionized water to make sodium dihydrogen phosphate into 3mol, ammonium acetate into 2mol mixed solution, open the reaction vessel for stirring, and put in Add 1 / 3 volume of deionized water to the container, and heat the bottom water to 40°C, add ferric sulfate to the reaction container at a flow rate of 5-15ml / min, and add sodium dihydrogen phosphate to the reaction container at a flow rate of 5-15ml / min In the container, by adjusting the flow rate of sodium dihydrogen phosphate, the pH value is controlled to 3.0±0.8, and the precipitate suspension generated by the reaction overflows to another container for aging. After aging for 6 hours, the precipitate is washed until the washing water The pH is greater than 6.8, then filtered, and the filter cake is baked in an oven at 100-120°C for 4-15 hours to obtain high-density spherical iron phosphate.

Embodiment 3

[0027] Use deionized water to make ferric nitrate into 4mol, ammonium citrate into 2mol mixed solution, use deionized water to make ammonium dihydrogen phosphate into 3mol, ammonia water into 2mol mixed solution, open the reaction container and stir it, put it into the container 2 / 3 volume of deionized water, heat the bottom water to 40°C, add ferric nitrate into the reaction vessel at a flow rate of 5-15ml / min, and add ammonium dihydrogen phosphate into the reaction vessel at a flow rate of 5-15ml / min In the process, by adjusting the flow rate of ammonium dihydrogen phosphate, the pH value is controlled to be 3.0±0.8, and the precipitate suspension generated by the reaction overflows to another container for aging. After aging for 6 hours, the precipitate is washed until the washing water pH If it is greater than 6.8, then filter, and bake the filter cake in an oven at 100-120°C for 4-15 hours to obtain high-density spherical iron phosphate.

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PUM

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Abstract

The invention relates to a high-density spherical ferric phosphate and a preparation method thereof, and preparation materials are mainly used for preparing ferrous phosphate lithium which is the anode material of a lithium ion battery. The preparation method takes an iron source and an additive as raw materials, and the raw materials are dissolved by vaal water to be made into a mixed solution A; the preparation method takes phosphate and a neutralizing agent as raw materials, and the raw materials are dissolved by the vaal water to be made into a mixed solution B. The solution A and the solution B are mixed and reacted, preparation materials are washed and parched, and the high-density spherical ferric phosphate the average grain diameter of which is 1.5-5micron, the tap density is not less than 0.95g/cm<3>, the grains are dispersed and the sizes are symmetrical is obtained. The ferrous phosphate lithium prepared by the high-density spherical ferric phosphate has perfect crystal structure, lithium ion intercalation/de-intercalation channel is normal, and the discharge capacity can reach 140mAh/g under the condition of 1C. The preparation method has simple process and is easy to technologize, and the ferrous phosphate lithium synthetized by the ferric phosphate has good crystallinity and crystal structure and can increase the electrochemical properties of the ferrous phosphate lithium.

Description

technical field [0001] The invention relates to a method for preparing high-density spherical iron phosphate, and the prepared material is mainly used for preparing lithium iron phosphate, a cathode material of a lithium ion battery. Background technique [0002] Lithium-ion battery is a new type of power source, which has many advantages such as high voltage, large capacity, safety and environmental protection, so it is widely used in the field of secondary batteries. [0003] At present, lithium-ion batteries are mainly lithium cobalt oxide cathode materials, but cobalt is a strategic resource and resources are in short supply. The thermal stability of lithium cobalt oxide is relatively poor, and it is difficult to meet the safety requirements of lithium-ion batteries as power. The lithium-ion secondary battery with lithium iron phosphate as the positive electrode material has excellent thermal stability and stable cycle charge and discharge performance, and is called "the...

Claims

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Application Information

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IPC IPC(8): C01B25/37
Inventor 吕向阳左一村
Owner GUANGZHOU RONGJIE MATERIAL TECH
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