All-solid-state asymmetric supercapacitor based on reduced graphene oxide/carbon nanotube and carbon fiber paper/polypyrrole electrodes

Sandwich-like reduced graphene oxide/carboxylated multi-walled carbon nanotube (RGO/cMWCNT) hybrid film and the carbon fiber paper-supported polypyrrole (CFP/PPy) composite film were prepared by a vacuum-infiltration process and an electrochemical deposition method, respectively. Furthermore, a novel all-solid-state asymmetric supercapacitor (ASC) was fabricated using RGO/cMWCNT as the negative electrode and CFP/PPy as the positive electrode, separated with potassium polyacrylate/KCl gel electrolyte. Due to the unique structure, stable potential window and good capacitive performance of the two electrodes, the as-fabricated ASC can be cycled reversibly at a cell voltage of 1.6 V and displays outstanding performances with an energy density of 28.6 W h kg−1 and a power density of 15.1 kW kg−1. Additionally, our ASC device also presents a superior long cycle life with 93% capacitance retention after 2000 cycles.