Supercapacitors based on patronite–reduced graphene oxide hybrids: experimental and theoretical insights

Abstract

Here we report the hydrothermal synthesis and detailed study on supercapacitor applications of a patronite hybrid, VS₄/reduced graphene oxide, which showed an enhanced specific capacitance of ∼877 F g⁻¹ at a current density of 0.5 A g⁻¹. In comparison to bare vanadium sulfide and reduced graphene oxide, the hybrid showed ∼6 times and ∼5 times higher value of specific capacitance, respectively. The obtained energy density (117 W h kg⁻¹) and power density (20.65 kW kg⁻¹) are comparable to those of other reported transition metal sulfides and their graphene hybrids. Theoretical calculations using density functional theory confirm an enhanced quantum capacitance of VS₄/graphene composite systems, owing primarily to the shifting of the graphene Dirac cone relative to the band gap of VS₄. The results infer that the hybrid has the potential to be used as a high performance supercapacitor electrode.