The electrochemical behavior of lifePO4/C cathode materials doped with antimony

Abstract

LiFePO4 is considered as a practical cathode material because of low raw materials' cost, excellent thermal safety, environmental friendliness, and long operational life, despite obstacles such as low tap density, low electric conductivity and slow lithium-ion diffusion. To overcome these problems, we used an antimony-ion doping method to synthesize LiFePO4/C with sebacic acid as a carbon source by a high-temperature solid-state reaction method. The effects of antimony concentration, sebacic acid content, calcination temperature, and calcination time on cell performance were investigated. After Sb3+ doping, LiFePO4 was converted to a p-type semiconductor and demonstrated greater electric conductivity of about 10-3 S cm-1. The 1.0 mol.% Sb-doped LiFePO4/C synthesized with 36 wt.% sebacic acid delivered an initial discharge capacity of 154 mAh g-1 at a 0.2 C-rate between 4.0-2.8 V. The doped cathode materials were further characterized by X-ray diffractometer (XRD), scanning electron microscope (SEM), and high-resolution transmission electron microscope (TEM) techniques for structural analysis and confirmation. © 2010 WEVA.