Preparation method of high-density non-ball shape ferric phosphate powder body

Abstract

The invention discloses a preparation method of a high-density non-ball shape ferric phosphate powder body which relates to a ferric compound. The invention aims to provide the preparation method of a high-density non-ball shape ferric phosphate powder body, and the ferric phosphate prepared by the method has high jolt density, small granule size and high specific surface area. The adopted technical scheme is as follows: a mixed water solution with a certain concentration of (FeNO3)3.9H2O and H3PO4 is prepared, (the mole ratio of Fe and P is 0.9:1.0); the mixed water solution is placed into a reactor, an ammonia solution is gradually added under a certain temperature and agitation until the pH value of the reaction liquid reaches 1 to 4 to obtain ferric phosphate slurry; the slurry is injected into a plate and frame filter press to obtain a filtered cake by pressing and filtration, the filtered cake is dried, soluble impurity ions are removed by water washing, and the washed material is dried again, pulverized and sieved to obtain the ferric phosphate powder body. The invention is used for the anode material of lithium ion batteries.

Description

Technical field: [0001] The invention belongs to a kind of iron compound, especially a kind of high-density iron phosphate (FePO 4 ) powder preparation method. technical background: [0002] Olivine Lithium Ferrous Phosphate LiFePO 4 Non-toxic, environmentally friendly, good safety performance, stable high temperature performance, rich raw materials, cheap price, high specific capacity (170mA.h.g -1 ) and good cycle performance, it is expected to replace the higher cost LiCoO 2 Become a new generation of lithium-ion battery cathode material. However, lithium iron phosphate has two main disadvantages. One is the extremely low electronic conductivity and proton diffusion rate, resulting in poor high-rate charge and discharge performance and low actual specific capacity; the other is low tap density, resulting in low volume specific capacity. These two shortcomings hinder the practical application of this material. In recent years, people doped Mg into the lithium iron pho...

AI Technical Summary

Problems solved by technology

In order to improve material uniformity and reduce cost, many documents adopt ferric phosphate as the raw material of synthetic lithium ferrous phosphate, for example: CN101172594A, CN101172595A, CN101237042A, CN1800003A, CN101237043A etc. report or relate to the preparation of ferric phosphate, these methods not only involve adding oxidizing agent , surfactants, etc., and the prepared iron phosphate has a low tap density, which cannot effectively improve the tap density of the lithium iron phosphate material

CN101244813A has reported that ferric phosphate with higher tap density is obtained by high-temperature sintering by the synthesized basic ammonium ferric phosphate, but the process is complicated and the energy consumption is higher

However, the preparation process conditions of the spherical ferric phosphate are relatively harsh, and the spherical particle size is large and the specific surface is small, which causes the diffusion channel of lithium ions in the solid phase to be lengthened, and the solid-liquid contact surface is small, which affects the high current of lithium ferrous phosphate. Charge and discharge performance

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