Novel synthesis of LiFePO4–Li3V2(PO4)3 composite cathode material by aqueous precipitation and lithiation

LiFePO4–Li3V2(PO4)3 composite cathode material is synthesized by aqueous precipitation of FeVO4·xH2O from Fe(NO3)3 and NH4VO3, following chemical reduction and lithiation with oxalic acid as the reducer and carbon source. Samples are characterized by XRD, SEM and TEM. XRD pattern of the compound synthesized at 700 °C indicates olivine-type LiFePO4 and monoclinic Li3V2(PO4)3 are co-existed. TEM image exhibits that LiFePO4–Li3V2(PO4)3 particles are encapsulated with a carbon shell 5–10 nm in thickness. The LiFePO4–Li3V2(PO4)3 compound cathode shows good electrochemical performance, and its discharge capacity is about 139.1 at 0.1 C, 135.5 at 1 C and 116 mA h g−1 at 3 C after 30 cycles.