Hydrothermal Synthesis and Electrochemical Properties of Lithium Iron Phosphate

High-purity and well-crystallized LiFePO4 powders with uniformly distributed fine particles were synthesized in a direct hydrothermal reaction.The microstructure and morphology of the samples were characterized via XRD,SEM and constant current charge-discharge cycle test so as to investigate the influences of hydrothermal temperature/time on the electrochemical properties of as-prepared LiFePO4 powder.The results showed that increasing hydrothermal temperature/time benefits the improvement of crystallinity but coarsens the particles.The best electrochemical properties of the LiFePO4 hydrothermally synthesized are found at 200 ℃/5 hr with a specific capacity 138.0 mA·h·g-1 at 0.1C rate during initial discharging.It means that the hydrothermal synthesis is commercially practical.Moreover,adding the ascorbic acid and glucose in the hydrothermal synthesis can avoid efficiently the oxidation of Fe2+,thus enhancing the electric conductivity of LiFePO4 powder.