Functionalized graphene–polyaniline nanocomposite as electrode material for asymmetric supercapacitors

Abstract

A polyaniline/sulfonated graphene (PANI/SG) nanostructure was synthesized as electrode material for an asymmetric supercapacitor via a novel in situ chemical oxidative polymerization method including two oxidants. The composite’s structure and morphology were characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) measurements. Furthermore, the electrochemical performances of the composite were characterized by cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) techniques in detail. In addition, we have triumphantly manufactured an asymmetric supercapacitor (ASC) employing activated carbon (AC) and PANI/SG as the positive and negative electrodes, respectively. The ASC possessed an extended potential window (1.4 V), a remarkable cycling property (85.9% capacitance retention after 5000 cycles), and a satisfactory average energy and power density (23 Wh/kg and 6.1 kW/kg).