Improved rate and cycle performance of nano-sized 5LiFePO4$Li3V2(PO4)3/C via high-energy ball milling assisted carbothermal reduction
Nano-sized 5LiFePO4·Li3V2(PO4)3/C composite was synthesized via improved carbothermal reduction combined high-energy ball milling. XRD results reveal that the composite is composed of olivine LiFePO4 and monoclinic Li3V2(PO4)3 phases. Meanwhile small amounts of V3+ and Fe2+ as dopants entered into the lattices of LiFePO4 and Li3V2(PO4)3, respectively. Trace amounts of Fe2O3 in LiFePO4/C and Fe2P in 5LiFePO4·Li3V2(PO4)3/C were identified and quantified by magnetic tests. And magnetic parameters of 5LiFePO4·Li3V2(PO4)3/C are significantly different from LiFePO4/C. The 5LiFePO4·Li3V2(PO4)3/C presents initial discharge specific capacities of 145.2 mAh g¿1 and 133.9 mAh g¿1 and no capacity attenuations after 50 cycles can be observed at 2C and 5C respectively. Compared with LiFePO4/C, its rate capability and cyclic stability are both enhanced greatly. The mutual doping, synergistical effect of LiFePO4 and Li3V2(PO4)3 and contribution of Fe2P are mainly responsible for the excellent electrochemical performances.