Mg and Fe Co-doped Mn Based Olivine Cathode Material for High Power Capability

Abstract

Here we demonstrate that the electrochemical properties of Mn based olivine cathode materials can be significantly improved by small amount of co-dopants, Fe and Mg. While nucleation and growth are important in determining the kinetics of a two-phase reaction based olivine electrode, the presence of Fe and Mg in LiMnPO(4) framework notably enhances the power capability of a LiMnPO(4) electrode providing multiple nucleation sites. The electrochemical activity of an Fe-Mg co-doped Mn olivine cathode material measured by galvanostatic charge/discharge indicates that a discharge capacity of about 140 mAh g(-1) can be obtained at a C/5 rate and this high capacity is retained at even higher current rates (110 mAh g(-1) at 3C), which has yet to be achieved in LiMnPO(4) without nucleation enhancers. (C) 2011 The Electrochemical Society. [DOI:10.1149/1.3524260] All rights reserved.