Synthesis and characterization of high-density LiFePO 4/C composites as cathode materials for lithium-ion batteries

Abstract

To achieve a high-energy-density lithium electrode, high-density LiFePO 4/C composite cathode material for a lithium-ion battery was synthesized using self-produced high-density FePO 4 as a precursor, glucose as a C source, and Li 2CO 3 as a Li source, in a pipe furnace under an atmosphere of 5% H 2–95% N 2. The structure of the synthesized material was analyzed and characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The electrochemical properties of the synthesized LiFePO 4/carbon composite were investigated by cyclic voltammetry (CV) and the charge/discharge process. The tap-density of the synthesized LiFePO 4/carbon composite powder with a carbon content of 7% reached 1.80 g m −3. The charge/discharge tests show that the cathode material has initial charge/discharge capacities of 190.5 and 167.0 mAh g −1, respectively, with a volume capacity of 300.6 mAh cm −3, at a 0.1C rate. At a rate of 5C, the LiFePO 4/carbon composite shows a high discharge capacity of 98.3 mAh g −1 and a volume capacity of 176.94 mAh cm −3.