Charge transport mechanism in reduced graphene oxide/polypyrrole based ultrahigh energy density supercapacitor

In the present work, charge transport in graphene/polypyrrole supercapacitor which is relatively unexplored so far, is investigated to understand the respective contributions of graphene and polypyrrole, particularly, in the charge transport and storage capacity to improve the device properties. It is seen that the role of graphene is to increase the surface area and the charge carriers are mainly stored in the polypyrrole-modified graphene sheet, while the transport occurs primarily through polypyrrole backbone via overlapping large polaron tunneling mechanism. Electrochemical supercapacitor has been fabricated using this layered composite as electrode material to obtain large value (similar to 931 F/g) of specific capacitance. Furthermore, the optimized material demonstrated an excellent energy density (46.6 Wh kg(-1)) at an ultra-high power density (469 W kg(-1)), indicating a promising potential for industrial applications as energy storage device.