Production process of battery grade anhydrous iron phosphate
Iron phosphate(FePO4)is a key precursor for cathode material of lithium battery lithium iron phosphate(LiFePO4).The morphology and sulfur content of FePO4 significantly impact the performance of the synthesized LiFePO4.To achieve FePO4 products with suitable particle size and low sulfur content,the liquid phase precipitation method is improved and optimized.Instead of adding phosphoric acid and ammonia water solely,ammonia water is mixed with phosphoric acid to form monoammonium phosphate,which is then added to FeSO4 solution,this effectively reduced the sulfur content.During the aging process,the crystallinity and morphology of FePO4 are changed by staged heating and adding ammonia water and phosphoric acid at different stages.The FePO4 products prepared under this method have a low sulfur mass fraction of 4.2×10-5,a morphology of block-like flake mixed particles,and the compaction density of LiFePO4 produced by this FePO4 is 2.53 g/cm3.
battery grade iron phosphateproduction processlow sulfur contentmorphology
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