Superior rate performance of Li3V2(PO4)3 co-modified by Fe-doping and rGO-incorporation

Abstract

Reduced graphene oxide (rGO) incorporated Li₃V_1.94Fe_0.06(PO₄)₃/C cathode materials were successfully prepared by a sol–gel method. Compared with Li₃V₂(PO₄)₃/C and single rGO-incorporated Li₃V₂(PO₄)₃/C, the rGO-incorporated Li₃V_1.94Fe_0.06(PO₄)₃/C electrode has the highest initial capacity of 164.4 mA h g⁻¹ with a capacity retention ratio of 83.5% after 100 cycles at 1C. When charged/discharged for 1000 cycles at 5C, it exhibits a prominent capacity of 129.3 mA h g⁻¹ with a capacity retention ratio of 91.5% and a very low capacity fading of 0.0085% per cycle. The superior electrochemical performance of Fe-doped and rGO-incorporated Li₃V₂(PO₄)₃ can contribute to the reduced particle size, the improved electronic conductivity, and the increased Li-ion diffusion coefficient. We believe this novel co-modification with Fe-doping and rGO-incorporation is an efficient way for Li₃V₂(PO₄)₃ and any other polyanion cathode materials to realize their application in power lithium ion battery.