Silver-decorated reduced graphene oxide nanocomposite for supercapacitor electrode application

Abstract

Silver-decorated reduced graphene oxide (Ag@rGO) nanocomposite was synthesized via a facile chemical reduction method, and its morphology, functional groups, structure, optical and electrical characteristics were investigated. Large distributions of spherical Ag nanoparticles with particle size ranging from 108 to 126 nm anchored into rGO sheets were observed. The energy dispersive X-ray confirms the presence of carbon, oxygen and silver elements in the Ag@rGO nanocomposite. Fourier-transform infrared spectrum exhibited stretching vibrations due to C=O, C–H₂, C–O, C=C, O–H and Ag–O bonds in Ag@rGO nanocomposite. X-ray diffraction results of Ag@rGO nanocomposite confirm the formation of rGO and metallic Ag nanoparticles exhibiting FCC structure. The bandgap and I_D/I_G values of Ag@rGO nanocomposite were obtained as 2.76 and 1.49 eV respectively. Moreover, the study of electrochemical properties of Ag@rGO nanocomposite was carried out, where the maximum specific capacitance of 717.3 and 433.05 F g⁻¹ was achieved at 5 mV s⁻¹ scan rate and 1 A g⁻¹ current density. Moreover, the impedance spectroscopy study exhibited the charge transfer resistance (R_CT) value as 6.98 and 71.29 Ω from the Nyquist and Bode plots. I–V characteristics curve shows that the addition of Ag into rGO increases its electrical conductivity. Thus, the results of Ag@rGO nanocomposite can be suitable for supercapacitor application.