Electrochemical performance of Mo-doped LiFePO4/C composites prepared by two-step solid-state reaction

To improve the performance of LiFePO4, LiFe1-x Mo (x) PO4/C (x = 0, 0.005, 0.010, 0.015, 0.020, 0.025) cathode materials were synthesized via two-step ball milling solid-state reaction. The prepared samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy, cyclic voltammetry, electrochemical impedance spectra, and galvanostatic charge-discharge test. It is apparent from XRD analysis that Mo doping enlarges the interplanar distance of crystal plane parallel to [010] direction in LiFePO4. In other words, it widens one-dimensional diffusion channels of Li+ along the [010] direction. The results of electrochemical test indicate that the LiFe0.99Mo0.01PO4/C composite exhibits a discharge capacity of 144.8 mAh g(-1) at 1 C rate, a decreased charge transfer resistance of 162.4 Omega and better reversibility of electrode reactions. The present synthesis route is promising and practical for the preparation of LiFePO4 materials.