Lithium secondary battery has been widely studied because of a large terminal voltage and a large energy density. Lithium-containing transition metal oxides, LiCoO2, LiNiO2, LiMn2O4, LiFePO4, and their derivatives have been investigated to obtain the high performance cathode active materials of lithium secondary battery. Among these cathode materials, LiFePO4 has flat voltage profile, good electrochemical and thermal stability, relatively low cost for synthesis, and environmental compatibility with less toxicity than other cathode materials. Due to these advantages, LiFePO4 has been attracting much attention as a promising new cathode electrode material for lithium-ion batteries. However, the low electric conductivity and low diffusion coefficient of Li+ are the main shortcomings that limit its application in industry. Extensive efforts have been performed to improve its electrochemical performance over decades.