Novel Synthesis of 3D Mesoporous FePO 4 from Electroflocculation of Iron Filings as a Precursor of High-Performance LiFePO 4 /C Cathode for Lithium-Ion Batteries.

This study presents an economic and environmentally friendly method for the synthesis of microspherical FePO 4 ·2H 2 O precursors with secondary nanostructures by the electroflocculation of low-cost iron fillers in a hot solution. The morphology and crystalline shape of the precursors were adjusted by gradient co-precipitation of pH conditions. The effect of precursor structure and morphology on the electrochemical performance of the synthesized LiFePO 4 /C was investigated. Electrochemical analysis showed that the assembly of FePO 4 ·2H 2 O submicron spherical particles from primary nanoparticles and nanorods resulted in LiFePO 4 /C exhibiting excellent multiplicity and cycling performance with first discharge capacities at 0.2C, 1C, 5C, and 10C of 162.8, 134.7, 85.5, and 47.7 mAh·g -1 , respectively, and the capacity of LiFePO 4 /C was maintained at 85.5% after 300 cycles at 1C. The significant improvement in the electrochemical performance of LiFePO 4 /C was attributed to the enhanced Li + diffusion rate and the crystallinity of LiFePO 4 /C. Thus, this work shows a new three-dimensional mesoporous FePO 4 synthesized from the iron flake electroflocculation as a precursor for high-performance LiFePO 4 /C cathodes for lithium-ion batteries.