Decoration of Nitrogen-Doped Reduced Graphene Oxide With Cobalt Tungstate Nanoparticles for Use in High-Performance Supercapacitors Publisher



Naderi HR¹ ; Sobhaninasab A² ; Rahiminasrabadi M³ ; Ganjali MR^{1, 4}
Source: Applied Surface Science Published:2017

Abstract

A composite of cobalt tungstate nanoparticles coated on nitrogen-doped reduced graphene oxide (CoWO 4 /NRGO) was prepared through an in situ sonochemical approach. The composite was next evaluated as an electrode material for use supercapacitors electrodes. The characterization of the various CoWO 4 /NRGO nanocomposite samples was carried out through field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), X-ray photoemission spectroscopy (XPS), Brunauer–Emmett–Teller (BET) method and Raman spectroscopy. Complementary studies were also performed through cyclic voltammetry (CV), galvanostatic charge/discharge, electrochemical impedance spectroscopy (EIS), and continues cyclic voltammetry (CCV). The electrochemical evaluations were carried out in a 2 M H 2 SO 4 solution as the electrolyte. The electrochemical evaluations on the nano-composite samples indicated that CoWO 4 /NRGO-based electrodes reveal enhanced supercapacitive characteristics (i.e. a high specific capacitance (SC) of 597 F g −1 at a scan rate of 5 mV s −1 , an energy density (ED) value of 67.9 W h kg −1 , and high rate capability). CCV studies indicated that CoWO 4 /NRGO-based electrodes keep 97.1% of their original capacitance after 4000 cycles. The results led to the conclusion that CoWO 4 /NRGO effectively merge the merits of CoWO 4 and CoWO 4 /RGO in one new nanocomposite material. © 2017 Elsevier B.V.