High capacitive performance of flexible and binder-free graphene-polypyrrole composite membrane based on in situ reduction of graphene oxide and self-assembly.

Exploiting flexible and binder-free electrode materials is of importance for the fast development of smart supercapacitor devices. A simple and effective strategy is demonstrated to fabricate a flexible composite membrane of reduced graphene oxide and polypyrrole nanowire (RGO-PPy) via in situ reduction of graphene oxide and self-assembly. More importantly, the shape and thickness of the membrane can be reasonably controlled by varying either the concentration of GO and PPy nanowires or the filtration volume. By direct coupling of two membrane electrodes, symmetric supercapacitors can be fabricated without the use of a binder and conductive additive. The supercapacitor is able to offer large areal capacitance (175 mF cm(-2)) and excellent cycling stability (~93% capacitance retention after 5000 charge-discharge cycles), thanks to the synergic integration between RGO sheets and PPy nanowires and the unique self-assembled porous structure.