Reduced graphene oxide supported highly porous V2O5 spheres as a high-power cathode material for lithium ion batteries

Abstract

Reduced graphene oxide (rGO) supported highly porous polycrystalline V₂O₅ spheres (V₂O₅/rGO) were prepared by using a solvothermal approach followed by an annealing process. Initially, reduced vanadium oxide (rVO) nanoparticles with sizes in the range of 10–50 nm were formed through heterogeneous nucleation on rGO sheets during the solvothermal process. These rVO nanoparticles were oxidized to V₂O₅ after the annealing process in air at 350 °C and assembled into polycrystalline porous spheres with sizes of 200–800 nm. The weight ratio between the rGO and V₂O₅ is tunable by changing the weight ratio of the precursors, which in turn affects the morphology of V₂O₅/rGO composites. The V₂O₅/rGO composites display superior cathode performances with highly reversible specific capacities, good cycling stabilities and excellent rate capabilities (e.g. 102 mA h g⁻¹ at 19 C).