Synthesis and Characterization of Ti Doped Lithium Iron Phosphate

Li1-4yTiyFePO4 (y = 0, 0.01, 0.02, 0.03, 0.04, and 0.05) cathode materials were prepared by solid-state reaction. The as-prepared samples were characterized by X-ray diffraction, X-ray absorption spectroscopy, cyclic charge-discharge, cyclic voltammograms, and electrochemical impendence spectroscopy. The x-ray diffraction results indicate that the Ti4+ incorporates into the LiFePO4 lattice, but the XAS reveals that small amount of doped Ti can also form TiO2-anatase impurities. At 0.1 C rate, doping of Ti causes a decrease in charge and discharge capacities. However, at higher C rate, the charge/discharge capacities are improved. 1 at.% doping sample Li0.96Ti0.01FePO4 exhibits the optimized electrochemical performance.