Reduced graphene oxide/gallium nitride nanocomposites for supercapacitor applications

Abstract

Reduced graphene oxide/gallium nitride (RGO–GaN) nanocomposites were synthesized by a facile single-step chemical reduction process with variation in the concentration of GaN from GaN1%@RGO–GaN to GaN20%@RGO–GaN. Scanning electron microscopy and X-ray diffraction results revealed that the particle sizes of the GaN nanoparticles,and the crystallite sizes of RGO–GaN nanocomposites, were in the ranges of178–379 and 0.243–0.245 nm, respectively. The Gaussian deconvolution of Ga(3s), N(1s), and Ga(2p) for GaN1%@RGO–GaN and GaN7%@RGO–GaN indicated various binding energies of core orbital electronic configuration for the GaN in the RGO–GaN nanocomposite networks. The X-ray photoelectron spectroscopy measurements showed the calculated atomic percentage of Ga and N for GaN1%@RGO–GaN and GaN7%@RGO–GaN ranged within 2.32–5.98% and 4.91–7.33%, respectively. The maximum specific capacitance was forGaN5%@RGO–GaNwith454 F/g at 10 mV/s scan rate as measured using cyclic voltammetry. Similar results were found using the galvanostatic charge–discharge method, resulting in specific capacitance of 116.8–146.1 F/g at a current density of 1A/g. Moreover, very low charge transfer resistance was developed, reaching a maximum of only 2.36 Ω for electrochemical impedance spectroscopy analysis. These electrochemical measurement results indicated good capacitive behavior of the RGO–GaN nanocomposites.