Synthesis of Sub-micrometer Lithium Iron Phosphate Particles Using Supercritical Hydrothermal Method for Lithium Ion Batteries

In this study, sub-micrometer LiFePO4 particles with high purity and crystallinity were synthesized using supercritical hydrothermal method as the cathode material for lithium ion batteries. Experimental results show that templates and calcination time have significant impacts on the purity, particle size and morphology of LiFePO4 particles. The as-prepared LiFePO4 particles using polyvinyl pyrrolidone （PVP） template with additional one hour calcination at 700 ℃ exhibit characteristics of good crystallinity, uniform size distribution, high capacity and cycling performance. The specific discharge capacities of 141.2 and 114.0mA.h/g were obtained at the charge/discharge rates of 0.1 and 1.0℃, respectively. It retained 96.0% of an initial capacity after 100 cycles at 1.0 C rate. The good electrochemical performance of the as-synthesized material is attributed to the synergistic factors of its reasonable particle size and surface areas and high crystallinity.