Flexible reduced graphene oxide/polypyrrole films for supercapacitors

The films with stable flexibility and excellent electrochemical properties are essential for fabricating portable and wearable supercapacitors. In this work, the free-standing, flexible reduced graphene oxide/polypyrrole nanotubes (rGO/PPy) films were prepared by the vacuum-filtration of PPy nanotubes and graphene oxide (GO) followed by the reduction treatment of KI and HCl solution. The prepared films exhibited remarkable flexibility, as they can withstand bending to 90 degrees more than 1000 times without experiencing any cracks. Furthermore, the symmetric supercapacitor of rGO/PPy exhibited an areal capacitance of 631 mF cm-2 and a volumetric capacitance of 117,000 mF cm-3, as well as the areal energy density of 56.1 mu Wh cm-2. Meanwhile, the electrochemical performance under various bending states was stable, and capacitance retention (86 %) after 800 bending cycles was achieved. These characteristics are essential for manufacturing wearable devices, portable electronics, and healthcare monitoring applications.