Facile synthesis of V2O5/graphene composites as advanced electrode materials in supercapacitors

Abstract

Hybrid electrode materials are key for electrochemical performances of supercapacitors. In this work, vanadium pentoxide (V2O5) is grown on graphene by a microwave synthetic method, which is simple, rapid, energy-saving and efficient. Benefiting from the microwave synthetic method, uniform V2O5 nanoparticles with an approximately size of 20 nm are evenly dispersed on graphene. The resultant V2O5/graphene composites are assembled into symmetrical supercapacitors, exhibiting specific capacitances of 673.2 and 474.6 F g−1 at 1 and 10 A g−1, respectively, and 96.8% of capacitance retention after 10,000 cycles at 1 A g−1. Additionally, the assembled devices show outstanding energy density and power density characteristics (46.8 Wh kg−1 at 499.4 W kg−1 and 32.9 Wh kg−1 at 4746.0 W kg−1), which are superior than many similar devices. Furthermore, capacitive performances of V2O5/graphene composites with five different component ratios are thoroughly investigated and the charge storage mechanism is discussed.