Research on the electrical electrochemical properties of the LiFe_(0.98)Mn_(0.02)(PO_4)_(1-0.02/3)Cl_(0.02)/C cathode materials

摘要

The Mn-Cl co-doped LiFePO_4 was succefully synthetized by two-step solid-state reaction. After doping, the Lattice constants shifted while the morphology changed only little, revealing that the properties may not be improved by the slight changed grain size but the crystal structure. The co-doped sample presented a high discharge capacity of 161.1mAhg~(-1) at 0.1C, 157.7mAhg~(-1) at 0.5C, 149.1mAhg~(-1) at 1C, nearly 30mAhg~(-1) higher than that of the pristine LiFePO_4/C respectively. The electrochemical reversibility and cycle stability of co-doped LiFePO_4/C were enhanced. Moreover, the Li~+ diffusion and exchange current density of that was increased after doped with Mn~(2+) and Cl~-.