Preparation of high purity iron phosphate based on the advanced liquid-phase precipitation method and its enhanced properties

Abstract

The traditional liquid-phase precipitation method has been a significant challenge when preparing iron phosphate. Herein, we optimized it by adding surfactants. The effects of surfactant types with the purity, morphology, particle size and structure of iron phosphate were studied. In contrast to many iron phosphate which undergo serious uncontrol morphology, such as particle size, agglomeration and so on, the optimized results show that rational use of surfactants can reduce the impurities content of iron phosphate, refine particle size, reduce particle agglomeration, and improve morphological consistency, while the effect of adding cationic surfactant CTAB is better than that of anionic surfactant SDBS. Moreover, lithium iron phosphate cathode materials were synthesized using iron phosphate prepared by adding different surfactants as precursors, and electrochemical performance tests were performed. The results reveal that the sample prepared with CTAB has excellent electrochemical performance, which is significantly better than the sample prepared without added surfactant. At a rate of 0.1 ​C, the specific discharge capacity is increased by 3.41%–158.74 ​mA ​h/g, and the capacity decay rate is reduced by 53.98%–1.34%, and the charge transfer resistance decreased by 69.6%–83.99 ​Ω, showing excellent potential industry application.