Novel synthesis of LiMnPO4·Li3V2(PO4)3/C composite cathode material
A carbon-coated LiMnPO4·Li3V2(PO4)3 composite cathode material is synthesized from a rod-like MnV2O6·4H2O precursor prepared via aqueous precipitation for the first time, followed by chemical reduction and lithiation with oxalic acid as the reducing agent and glucose as the carbon source. XRD results indicate that orthorhombic LiMnPO4 and monoclinic Li3V2(PO4)3 co-exist. SEM results reveal that the thickness of the rod-like MnV2O6·4H2O precursor is about 80 nm and that the LiMnPO4·Li3V2(PO4)3/C composite possesses a micro/nano sphere-like morphology. HRTEM results indicate that the sample is a core–shell structure, where the external shell is amorphous carbon and at the core of the sample are LiMnPO4, Li3V2(PO4)3 and LiMnPO4·Li3V2(PO4)3 unit cells. The initial discharge capacity of the LiMnPO4·Li3V2(PO4)3/C composite is 110 mA h g−1, 104.4 mA h g−1, 100.6 mA h g−1 and 80.4 mA h g−1 at the rate of 0.1 C, 1 C, 3 C and 10 C, respectively. The cell shows excellent cycling stability and good rate capability as a cathode for lithium-ion batteries.