Synthesis and Performances of LiMn_yFe_(1-y)PO_4 as Cathode Materials for Lithium-ion Batteries

The LiMnyFe1-yPO4 (0.1≤ y ≤1) cathode materials for lithium-ion batteries were synthesized by solid-state reaction combined with high-rate ball milling. The crystalline structure, morphology of particles, and electrochemical performance of the sample were investigated by X-ray diffraction, scanning electron microscope, charge-discharge test and cyclic voltammetry. The results show that all LiMnyFe1-yPO4 samples are simple pure olive-type phase with small particles, and uniformly distribution of gain sizes. At low rate of 0.1C, the first specific discharge capacity of LiMn0.1Fe0.9PO4 is the highest with 145mAh/g and LiMn0.6Fe0.4PO4 shows the highest energy density of 568Wh/kg. The rate capabilities of the samples are strongly influenced by y value of LiMnyFe1-yPO4. LiMn0.1Fe0.9PO4 shows the best rate capabilities with discharge capacity of 130mAh/g at 0.5C rate and 109mAh/g at 1.5C rate.