▎ 摘　　要

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 degrees 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 degrees C).