NiMoO4/reduced graphene oxide composite as an electrode material for hybrid supercapacitor

Abstract

In this paper, reduced graphene oxide/nickel molybdate (rGO/NiMoO4) nanocomposite was synthesized by a hydrothermal method followed by annealing at 450 °C. X-ray diffraction, Raman, and X-ray photoelectron spectroscopy analyses confirmed the formation of rGO/NiMoO4 nanocomposite. Field emission scanning electron microscopy analysis showed that the rod-like NiMoO4 nanostructures with a length of 1–5 μm were decorated on the rGO surface. In a three-electrode configuration, the rGO/NiMoO4 composite disclosed a capacitance of 680 F g−1 and maintained 68% of its starting capacitance after 4000 cycles at 3 A g−1. In the two-electrode configuration, the rGO/NiMoO4 electrode displayed a capacitance of 74 F g−1 besides an energy density of 26.3 Wh kg−1 at 0.75 A g−1 and retained 56.7% of the starting capacitance ensuing 4000 cycles at 1.5 A g−1. A 9 V hybrid supercapacitor disclosed a capacitance and energy density of 1.09 F g−1 and 12.3 Wh kg−1, respectively at 8 mA, and retained 72% of its starting capacitance after 1500 cycles.