Preparation method for lithium ion secondary battery positive pole active substance lithium iron phosphate

Abstract

The invention relates to a preparation method of lithium iron phosphate, an active substance applied in the anode of lithium-ion secondary batteries. The method comprises that a mixture that contains lithium compound, iron compound, phosphorus compound and carbon source additive is sintered and cooled to get a sintering product; wherein, the iron compound is ferric iron compound; the sintering method is carried out in inert atmosphere or reducing atmosphere; the mixture is sintered at a first constant sintering temperature, and the sintering product is acquired; the sintering product acquiredfrom sintering at the first sintering temperature is cooled to room temperature, ground and briquetted; the mixture is sintered at a second constant sintering temperature, and is cooled to room temperature in inert atmosphere or reducing atmosphere; the second sintering temperature is at least 100 DEG C higher than the first sintering temperature. The lithium iron phosphate acquired by the methodof the invention has relatively high specific discharge capacity and specific volumetric capacity, and the produced batteries have small size, high capacity and good discharge performance at high current, and the invention can combine the advantages of lithium iron phosphate prepared by taking ferrous iron and ferric iron as iron sources respectively, thus the performance can be remarkably improved.

Description

technical field

[0001] The present invention relates to a preparation method of a positive electrode active material of a battery, more specifically, to a preparation method of lithium iron phosphate, a positive electrode active material of a lithium ion secondary battery. Background technique

[0002] As a high-energy chemical power source, lithium-ion batteries have been widely used in mobile communications, notebook computers, video cameras, cameras, portable instruments and other fields. . LiFePO 4 It is a research hotspot of positive electrode active materials for lithium-ion batteries. LiFePO 4 As a positive electrode active material for lithium-ion batteries, compared with other batteries, it has good electrochemical performance, the charging and discharging platform is very stable, and the structure is stable during charging and discharging. The advantages of use and wide range of raw material sources are currently hot spots in the battery industry's development ...

Images