Synthesis and electrochemical performance of LiFePO4/C cathode materials from Fe2O3 for high-power lithium-ion batteries

Abstract

Carbon-coated olivine-structured LiFePO4/C composites are synthesized via an efficient and low-cost carbothermal reduction method using Fe2O3 as iron source at a relative low temperature (600 °C). The effects of two kinds of carbon sources, inorganic (acetylene black) and organic (sucrose), on the structures, morphologies, and lithium storage properties of LiFePO4/C are evaluated in details. The particle size and distribution of the carbon-coated LiFePO4 from sucrose (LiFePO4/SUC) are more uniform than that obtained from acetylene black (LiFePO4/AB). Moreover, the LiFePO4/SUC nanocomposite shows superior electrochemical properties such as high discharge capacity of 156 mAh g−1 at 0.1 C, excellent cyclic stability, and rate capability (78 mAh g−1 at 20 C), as compared to LiFePO4/AB. Cyclic voltammetric test discloses that the Li-ion diffusion, the reversibility of lithium extraction/insertion, and electrical conductivity are significantly improved in LiFePO4/SUC composite. It is believed that olivine-structured LiFePO4 decorated with carbon from organic carbon source (sucrose) using Fe2O3 is a promising cathode for high-power lithium-ion batteries.