Method for preparing lithium iron phosphate based on liquid-phase ion-level mixed contact coating doping process

Abstract

The invention discloses a method for preparing lithium iron phosphate based on liquid-phase ion-level mixing, contacting, coating and doping processes. According to the method, an iron source compound is added into a reactor pre-contained deionized water, and stirring is conducted uniformly to obtain mixed liquid a; then, an aqueous solution of coated and doped metallic elements is prepared, and a precipitant solution which can make the aqueous solution of the doped metallic elements form precipitation is prepared; then, the prepared aqueous solution of the doped metallic elements and the prepared precipitant solution are uniformly added into the mixed liquid a according to a certain proportion, the PH value of reaction liquid, the reaction temperature, the stirring speed and the speed of adding materials are controlled, an iron source compound with uniform surface doping is formed, and washing and drying are conducted; finally, the coated iron source compound is ball-milled and mixed with lithium sources, phosphorus sources and carbon sources of which the molar ratio corresponds to that of the coated iron source compound, calcination is conducted under the protection of inert gas, and products are obtained after natural cooling. By the adoption of the method for preparing the lithium iron phosphate based on the liquid-phase ion-level mixing, contacting, coating and doping process, the lithium iron phosphate is uniform in doping, good in crystallinity, high in voltage platform, good in rate discharge, excellent in low-temperature performance and high in constant-current ratio.

Description

technical field [0001] The invention belongs to the technical field of new energy materials, and relates to a synthesis method of a positive electrode material of a lithium-ion power battery, in particular to a method for preparing lithium iron phosphate based on a liquid-phase ion-level mixed contact coating doping process. Background technique [0002] With the continuous development of social civilization, especially when human society has entered the era of rapid development, human demand for energy and environmental protection are also increasing, which promotes the development and research of new energy in society. And batteries, especially lithium-ion batteries, will inevitably play a pivotal role in the future society based on electric energy, and will become an indispensable and important supporting product in new energy and other industrial fields. [0003] Due to the depletion of oil and other energy sources, nuclear energy, water energy, solar energy, etc. will b...

AI Technical Summary

Problems solved by technology

[0006] The fatal shortcoming of the development of lithium iron phosphate is poor conductivity. The current mainstream technologies to solve this problem are: conductive carbon-coated particles, metal ion doping, and micronization of particles by nano-processing, etc.