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

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, ...

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 increased costs

[0004] On the other hand, my country is rich in siderite resources. At present, iron is mainly used to make iron, while other elements such as magnesium and manganese have not been well utilized. This not only wastes resources, but also causes serious pollution to the environment.