Surface modification of reduced graphene oxide‐polyaniline nanotubes nanocomposites for improved supercapacitor electrodes

Abstract In the present work, irradiation with high energetic ions has been used for surface, structural, and morphological modifications of reduced graphene oxide (RGO) and polyaniline nanotubes (PAniNTs) nanocomposites with a view to enhance their electrochemical performance as supercapacitor electrode. High‐resolution transmission electron microscope micrographs depict defect induced fragmented morphology with stable inner hollow tubes up to a fluence of 2.2 × 10¹² ions cm⁻², above which drastic degradation of PAniNTs is observed. Irradiation induced annealing effects and structural disorder at varied irradiation fluences have been investigated by micro‐Raman spectroscopy. Formation of shorter PAniNTs of higher surface area due to generation of ion irradiation induced defects and their reorganization results in increased Brunauer‐Emmett‐Teller specific surface area and porosity. Surface energy and wettability of the electrodes increase upon ion irradiation, which improves electrode‐electrolyte interaction at the interface. Surface free energy calculations indicate increased concentration of polar groups on the nanocomposite electrode surface upon irradiation. Electrochemical performance studies indicate enhancement in specific capacitance and cyclic stability from 448 F g⁻¹ and 89% for unirradiated nanocomposite to 482 F g⁻¹ and 92%,_, respectively, for the nanocomposite irradiated at 2.2 × 10¹² ions cm⁻² fluence, which is attributed to the increased surface energy and porosity upon irradiation giving rise to increased electrochemically active sites for charge storage in the electrode.