Vanadium oxide nanowire – Graphene binder free nanocomposite paper electrodes for supercapacitors: A facile green approach

Vanadium oxide has attracted interest for energy storage applications due to its high theoretical capacitance and stable layered structure. The low electronic conductivity, of V2O5 necessitates combining with conducting materials, typically carbon. However combining with conductive carbon materials may require binders, which compromise the active surface. In this study, V2O5 nanowire (VNWs)–graphene composite flexible paper electrodes were prepared without using binders. Graphene introduces conductivity and electric double layer capacitance (EDLC) to the composite. Graphene sheets were prepared using an alkaline deoxygenation process (hGO), which is a green alternative to traditional hydrazine reduction. Coin cell type supercapacitors were assembled using the hGO–VNW paper electrodes as the anode and spectracarb fiber cloth as the cathode in a two-electrode cell configuration. Electrochemical studies for different compositions of VNWs on hGO are reported. The composite electrode hGO–VNW120, showed balanced EDL and pseudocapacitance as well as an energy density of 38.8 Wh kg−1 at a power density of 455 W kg−1. The maximum power density of 3.0 kW kg−1 was delivered at a constant current discharge rate of 5.5 A g−1. The device prepared using hGO–VNW120 anode showed a specific capacitance of 80 F g−1.

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► A facile green method was developed to grow VNWs on graphene surface.
► These VNWs are physically bonded on to the graphene surfaces.
► Flexible composite paper electrodes were prepared without using binders.
► The effect of the composition of VNWs in electrodes on electrochemical properties was studied.
► hGO–VNW paper electrodes show high power and energy densities.