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