Characterization and electrochemical performances of MoO2 modified LiFePO4/C cathode materials synthesized by in situ synthesis method

The MoO2 modified LiFePO4/C cathode materials were synthesized by in situ synthesis method. Phase compositions and microstructures of the products were characterized by X-ray powder diffraction (XRD), SEM, TEM and EDS. Results indicate that MoO2 can sufficiently coat on the LiFePO4 surface and does not alter LiFePO4 crystal structure, the existence of MoO2 decreases the particles size and increases the tap density of cathode materials. The electrochemical behavior of cathode materials was analyzed using galvanostatic measurement, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results show that the existence of MoO2 improves electrochemical performance of LiFePO4 cathode materials in specific capability and lithium ion diffusion and charge transfer resistance. The initial charge-discharge specific capacity and apparent lithium ion diffusion coefficient increase, the charge transfer resistance decreases with MoO2 content and maximizes around the MoO2 content is 5 wt%. It has been had further proved that the MoO2 adding enhances the electronic conductivity and lithium ion transport to improve the electrochemical performance of LiFePO4 cathode materials. (C) 2014 Elsevier B.V. All rights reserved.