Nanocomposites of Sulfonic Polyaniline Nanoarrays on Graphene Nanosheets with an Improved Supercapacitor Performance

A new nanocomposite, poly(aniline-co-diphenylamine- 4-sulfonic acid)/graphene (PANISP/rGO), was prepared by means of an in situ oxidation copolymerization of aniline (ANI) with diphenylamine-4-sulfonic acid (SP) in the presence of graphene oxide, followed by the chemical reduction of graphene oxide using hydrazine hydrate as a reductant. The morphology and structure of PANISP/rGO were characterized by field-emission (FE) SEM, TEM, X-ray photoelectron spectroscopy (XPS), Raman, FTIR, and UV/Vis spectra. The electrochemical performance was evaluated by cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impe-dance spectroscopy. The PANISP/rGO nanocomposite showed a nanosized structure, with sulfonic polyaniline nanoarrays coated homogeneously on the surface of graphene nanosheets. This special structure of the nanocomposite also facilitates the enhancement of the electrochemical performance of the electrodes. The PANISP/rGO nanocomposite exhibits a specific supercapacitance up to 1170 Fg(-1) at the current density of 0.5 Ag-1. The as-prepared electrodes show excellent supercapacitive performance because of the synergistic effects between graphene and the sulfonic polyaniline copolymer chains.