Effects of Fe doping on the electrochemical performance of LiCoPO4/C composites for high power-density cathode materials

LiCo1−xFexPO4/C composites with various amounts of Fe (x = 0, 0.05 and 0.1) were synthesized by vibrant type ball-milling coupled with microwave heating to investigate the role of doped Fe2+ in LiCo1−xFexPO4/C composites. The initial charge–discharge curves and cyclic voltammetry profiles of LiCo1−xFexPO4/C composites apparently featured an improved kinetic property compared to LiCoPO4. It was observed that the initial discharge capacity (120 mA hg−1) of LiCo0.95Fe0.05PO4 is higher than that (108 mA hg−1) of LiCoPO4 and the difference between the oxidation–reduction peaks is getting smaller with the increase of Fe doping. The electrochemical improvement in LiCo1−xFexPO4/C composites could be attributed to the enhanced Li+ diffusivity induced by the enlargement of 1D channel in polyanion structure of LiCoPO4.