Dopamine-assisted chemical vapour deposition of polypyrrole on graphene for flexible supercapacitor

Highlights: • Graphene/dopamine/polypyrrole (CDPY) hybrid nanocomposites are fabricated. • Dopamine promotes capturing the cations of initiators, acting as a dispersing agent. • CDPY electrodes are prepared on flexible substrate for applying supercapacitor. • Charge transfer reactions of polypyrrole improve the electrochemical behaviours. Developing high-performance carbon-based flexible supercapacitors is crucial for energy-storage systems with high stability and safety. Here we report a succinct method of fabricating polypyrrole (PPY) by chemical vapour deposition polymerization on flexible graphene substrate. The dependency of initiators such as FeCl₃ and CuCl₂ for the polymerization of pyrrole is elucidated as well. The morphological changes as well as doping concentrations of PPY affect the capacitive behaviours of the nanocomposites. In addition, an assistance of dopamine between PPY and graphene not only improves the uniformity of PPY layers, but also enhances the supercapacitor performance. These results demonstrate the potential for the wearable energy-storage devices application.