Method for synthesizing nano lithium iron phosphate without water of crystallization through atmospheric water phase

Abstract

The invention discloses a method for synthesizing nano lithium iron phosphate without water of crystallization through an atmospheric water phase, belonging to a method for preparing lithium-ion positive materials. The preparation process comprises the following steps of: preparing lithium phosphate, preparing a lithium phosphate water-phase suspension, preparing a ferrous salt solution, preparing the nano lithium iron phosphate without water of crystallization and recovering and recycling lithium in a lithium iron phosphate mother solution. The method has the beneficial effects of mild reaction condition, less time bucket, low energy consumption, stable batch and uniform and controllable force; as the lithium in the mother solution is recovered and recycled, the cost can be reduced; the method is beneficial to industrial production.

Description

technical field [0001] The invention relates to a preparation method of a positive electrode material of a lithium ion battery, in particular to a preparation method of nanometer crystal-free lithium iron phosphate synthesized in an aqueous phase at normal pressure. Background technique [0002] Lithium ferrous phosphate is a kind of positive electrode material of lithium ion battery. Lithium ferrous phosphate (LiFePO 4 ) crystal has the advantages of low price, less pollution, high capacity, stable structure during charge and discharge process, small capacity attenuation and high safety performance compared with other lithium ion battery cathode materials. Therefore, since it was discovered by Goodenough et al. in 1997 that it has lithium intercalation and desorption properties, lithium iron phosphate has been considered as one of the ideal cathode materials for lithium-ion batteries. [0003] The main methods for synthesizing lithium ferrous phosphate include high-tempera...

AI Technical Summary

Problems solved by technology

Among them, the main problem of the solid-phase method is that the product batch stability is poor, which directly leads to the short plate reaction of the battery pack; the precursor obtained by the solution co-precipitation method and the sol-gel method is not lithium iron phosphate, but a variety of substances It is difficult to achieve the consistency of each component of the mixture, and the obtained precursor needs to be calcined again at a high temperature to obtain the lithium iron phosphate crystal, which makes the process long, the product consistency is poor, and the equipment investment is large; the hydrothermal method and Although the solvothermal method can directly obtain lithium iron phosphate crystals, it requires high temperature and high pressure reaction equipment, which requires huge investment and is not suitable for large-scale industrial production.

Images