Fabrication and Electrochemical Capacitive Behavior of Freestanding Graphene/Polyaniline Nanofibre Film

Abstract

A freestanding film composed of graphene (GN) sheets and polyaniline (PANI) nanofibres was fabricated by reducing a graphite oxide (GO)/PANI precursor that was prepared by flow-directed assembly from a complex dispersion of GO and PANI. This was followed by reoxidation and redoping of the reduced PANI in the composite to restore the conducting PANI structure. A scanning electron microscope (SEM) image indicates that the GN/PANI film is a layered structure with PANI nanofibres uniformly sandwiched between the GN sheets. In the composite film, the PANI nanofibres can increase the basal spacing between GN sheets. Therefore, electrolyte ions have better accessibility to the GN surfaces. The GN sheets can act as current collector to decrease the inner resistance of the electrode, which is convenient for electronic and ionic transportation during the redox process of PANI. The electrochemical properties of the freestanding GN/PANI film were estimated by cyclic voltammetry and galvanostatic charge-discharge in 1 mol •L-1 HCl electrolyte. Electrochemical analysis demonstrates that the as-prepared GN/PANI film has good capacitive behavior. The specific capacitance was 495 F•g-1 at a current density of 0.1 A•g-1 and the capacitance was 313 F•g-1 even at a current density of 3 A•g-1. After 2000 cycles, the capacitance of the GN/PANI film decreases 10% of its initial capacitance, which demonstrates that the GN/PANI electrode has good cycle stability.