Nanocomposite of (α-Mn3O4/MnO)@rGO as a high performance electrode material for supercapacitors

Abstract

It is demonstrated for the first time, strongly coupled reduced graphene oxide with α-Mn3O4/MnO nanocomposite acts as an electrode material for supercapacitors. The material has displayed an optimum specific energy of 21 and 10.8 Wh/kg, and a power density of 206 and 3979 W/kg at the constant current values of 1 and 20 mA respectively. Furthermore, capacity retention of ~92.7 % was observed after 3000 cycles at a scan rate of 100 mV/s. This material was synthesized via a single step sol-gel route and subsequently calcined at 700 °C in an inert atmosphere (N2). The obtained (α-Mn3O4/MnO)@rGO nanomaterial was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscope (HR-TEM), scanning tunneling electron microscope-energy dispersive x-ray spectroscopy (STEM–EDS) to investigate the phase and structural morphology. Furthermore, electrochemical studies such as cyclic voltammetry (CV), Galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy for the nanocomposite were performed with three electrode systems in an aqueous electrolyte of 1 M KOH. © 2021