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

Abstract

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. (c) 2008 Elsevier B.V. All rights reserved.