Reduced graphene oxide/polypyrrole composite: an advanced electrode for high-performance symmetric/asymmetric supercapacitor

Polypyrrole (PPy) decorated on reduced graphene oxide (rGO) films is successfully prepared with pyrrole (Py) monomers and rGO through one-step combining oxidation with polymerization reaction. Compared with the pure individual components, rGO/PPy compound turns out better electrochemical characteristics owing to the introduction of rGO sheets, which improves the specific surface area and the conductivity of composite material. When the amount of rGO is 10% of the total, the rGO/PPy compound delivers the best capacitance of 389.3 F g(-1) at 1.0 A g(-1) in a three-electrode system and 266.8 F g(-1) at 0.25 A g(-1) in the symmetric supercapacitor system. In addition, asymmetric device (rGO/PPy//AC) has been successfully fabricated using optimized rGO/PPy compound as positive electrode, activated carbon as negative electrode (AC) and 1 M-Na2SO4 aqueous solution as electrolyte. The device obtains long cycle stability under the high-voltage region from 0 to 1.6 V, meanwhile displaying the satisfied energy density of 19.7 Wh kg(-1) at 478.1 W kg(-1). Besides, the rGO/PPy//AC device presents satisfactory rate capability and long life time.