The fabrication of bowl-shaped polypyrrole/graphene nanostructural electrodes and its application in all-solid-state supercapacitor devices

Conductive polymers (CPs) have potential for commercial energy storage applications because of their high electrochemical activity and low cost. However, one of the obstacles in developing CPs based supercapacitors is to overcome the capacitance degradation during the charge-discharge process, along with the poor rate performance. In this work, a unique bowl-shaped graphene/polypyrrole (PPy) nanostructure is uniformly grown on a graphite substrate by two facile electrochemical steps. The graphene is uniformly coated by PPy layers, while the thickness of the PPy layer depends on deposition time. The unique structural design for the PPy layer exhibits a significant influence on its electrochemical properties, and competitive performance is achieved by the GP-1200 based supercapacitor devices. It exhibits a maximum energy density of 5.18 mWh.cm(-3) and a maximum power density of 250.5 mW cm(-3), which are both comparable to values obtained from other solid-state supercapacitor devices.