Abstract:
The V
2O
3-C dual-layer coated LiFePO
4 cathode materials with excellent rate capability and cycling stability were prepared by carbothermic reduction of V
2O
5. X-ray powder diffraction, elemental analyzer, high resolution transmission electron microscopy and Raman spectra revealed that the V
2O
3 phase co-existed with carbon in the coating layer of LiFePO
4 particles and the carbon content reduced without graphitization degree changing after the carbothermic reduction of V
2O
5. The electrochemical measurement results indicated that small amounts of V
2O
3 improved rate capability and cycling stability at elevated temperature of LiFePO
4/C cathode materials. The V
2O
3-C dual-layer coated LiFePO
4 composite with 1wt% vanadium oxide delivered an initial specific capacity of 167 mAh/g at 0.2 C and 129 mAh/g at 5 C as well as excellent cycling stability. Even at elevated temperature of 55 oC, the specific capacity of 151 mAh/g was achieved at 1 C without capacity fading after 100 cycles.