High performance hybrid supercapacitor based on a graphene-based hybrid nanocomposite

Supercapacitors are typical energy storage devices that are characterized according to their electrode materials and energy storage mechanisms. Electrode materials are crucial for the electrochemical performance of supercapacitors. Self-doped polyaniline/graphene (SDPA/G) as a new hybrid material electrode has been prepared to improve electrochemical performance of polyaniline in neutral solutions. The obtained nanoporous structure has been employed as a novel and low-cost electrode material in construction of supercapacitor. Different electrochemical methods including cyclic voltammetry (CV), galvanostatic charge–discharge (CD) and electrochemical impedance spectroscopy (EIS) methods are carried out to characterize electrochemical performance of this nanocomposite. Based on the obtained charge–discharge results, high specific capacitance value of 85 F g-1 has been calculated for supercapacitor (SDPA/G)//G at 15 mA cm-2. Long-life cycling is achieved by removing dissolved oxygen and using a mild pH electrolyte. Moreover, the proposed supercapacitor exhibits high capacitance retention of 90% at a higher current density (120 mA cm-2), indicating good electrochemical stability and rate capability. The performance of the proposed hybrid supercapacitor has been compared with two other symmetric cells.