Formic acid as additive for the preparation of high-performance FePO4 materials by spray drying method

High-performance ferric phosphate (FePO 4 ), with well-defined ellipsoid morphology and uniform particle size distribution , is successfully fabricated via a green spray drying method with formic acid as additive. It is found that the added formic acid plays a crucial role for the formation of the well-distributed FePO 4 particles. Benefited by the outstanding structure and properties of ferric phosphate prepared above, a high performance of lithium iron phosphate (LiFePO 4 ) has been prepared. It exhibits high capacity, especially at high charging/discharging rate (158.4   mAh   g −1 at 0.2   C and 107.3   mAh   g −1 at 10   C), and excellent cycling stability (without capacity fading after cycling for 200cycles at 1   C). All these impressive electrochemical performance could be ascribed to the FePO 4 precursor, and further attributed to the addition of formic acid, which may play as a template, resulting in the well-defined morphology, uniform particles size distribution, hierarchical pore structure , and high surface area of the ferric phosphate.