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

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. (C) 2020 Elsevier B.V. All rights reserved.