Abstract: The LiFePO₄/C composite cathode materials for lithiumion batteries were synthesized by a solid state reduction method. The crystalline structure, morphology of particles, and electrochemical performance of the sample were investigated by -ray diffraction, scanning electron microscope, charge-discharge test and cyclic voltammetry. The results show that the composite synthesized at 700℃ has a simple pure olivetype phase with small particles, and uniformly distribution of gain sizes, and shows the best electrochemical performances with 1^st discharge specific capacity 150.3mAh/g and 20 th discharge specific capacity retention ratio 99.2% at 0.1C rate. It also shows good rate capability with 131.4mAh/g, 122.1mAh/g at the high rate of 1.0C and 2.0C, respectively. With the excellent characteristic to resist overcharge, this composite can retain its microstructure even after long time overcharge, but it is vulnerable to overdischarge.

Key words: lithium-ion batteries, lithium iron phosphate, solid state reduction