Reduced graphene oxide/vanadium pentoxide nanocomposite as electrode material for highly rate capable and durable supercapacitors

Abstract

The nanocomposite from reduced graphene oxide (rGO) and vanadium pentoxide (V<inf>2</inf>O<inf>5</inf>) was synthesized by the chemical method to obtain a nanocomposite of rGO 7.69% /V<inf>2</inf>O<inf>5</inf> 92.31% (GV). The role of faradaic V<inf>2</inf>O<inf>5</inf> in storing high energy, in combination with rGO was studied and the energy storing parameters were determined from the liner discharge (from the slope of the discharge curve) approach and the non-linear discharge approach (from the integrated area of the discharge curve). The appropriateness of these methods is a matter of diverse views among the researchers when the specific capacitance (C<inf>s</inf>) of the composite electrode material, comprising of both non-faradaic and faradic material, has to be determined. The energy storage parameters obtained from these two different approaches are found to be differing to a large extent. The energy storage parameters obtained from linear discharge approach are, a high specific capacitance (C<inf>s</inf>) of 120.62 F g?1, a specific capacity (Q) of 144.74 C g?1, an energy density (E) of 24.12 W h kg?1 a power density (P) of 2.647 kW kg?1 and a columbic efficiency (?) of 79.22% at a current density of 2 A g?1. The nanocomposite retained 100% of its initial C<inf>s</inf> up to 5000 cycles. Also retained 38% of its initial C<inf>s</inf>, after 10,600 cycles at a potential scan of 400 mV s?1. © 2019