Enhanced electrochemical properties of MgF2 and C co-coated Li3V2(PO4)3 composite for Li-ion batteries

Monoclinic MgF2 and C co-coated Li3V2(PO4)(3) (LVP) has been investigated as long life cathode of lithium-ion battery. The X-ray diffraction (XRD) results reveal that MgF2 modification has not changed the structure of LVP/C. The high resolution transmission electron microscopy (HRTEM) shows that the thickness of the uniform amorphous hybrid coating is about 10 nm. The research shows that the novel co-coating significantly enhanced the electrochemical performance of LVP cathode material, which is attributed to synergistic effect between MgF2 and C coating. MgF2 layer can restrain the dissolution of V element and enhance the structural stability of LVP in the electrolyte. Meanwhile, the presence of the carbon coating enhances the electron conductivity. The electrochemical impedance spectroscopy (EIS) further demonstrates that the hybrid coating is beneficial for structural stability of LVP/C during cycling. In conclusion, it can be speculated that the hybrid coating of MgF2 and C should be an effective strategy to enhance the electrochemical performance of LVP. (C) 2015 Elsevier B.V. All rights reserved.