Preparation and characterization of LiFePO₄/C cathode materials with high-rate performance

The nano-LiFePO₄/C composites were prepared by means of wet grinding and following high temperature solid-state reaction using water-soluble phenolic resin, Li₂CO₃, and nano-FePO₄ as precursors. The composites were characterized by XRD, SEM, TEM, TG and Raman spectroscopy and their electrochemical performances were studied. The results show that the as-prepared LiFePO₄/C nano-composites are spherical-like particles which consist of a carbon shell with a thickness of about 5 nm and the LiFePO₄ core, and show excellent high-rate performance and cycling performance as the cathode for lithium ion batteries. The initial discharge capacities at rates of 0.2 C (1 C=170 mAh·g^-1), 0.5 C、1 C、2 C、5 C and 10 C are 151 mAh·g^-1, 150 mAh·g^-1, 146 mAh·g^-1, 142 mAh·g^-1, 132 mAh·g^-1 and 119 mAh·g^-1, respectively. The material still shows initial discharge capacity of 105 mAh·g^-1 even at 20 C and its capacity doesn’t decay after 50 cycles.