Pseudocapacitive polydopamine functionalized on reduced graphene oxide as hybrid supercapacitor electrodes

Herein, we report hybrid electrodes using mussel-inspired redox-active polydopamine (PDA) functionalized on reduced graphene oxide (rGO) for high-performance supercapacitors. The extent of polymerization of dopamine is controlled by the polymerization time of dopamine that demonstrates the optimized conditions for hybrid electrodes in terms of electrochemical performances. Particularly, the PDA provides not only hydroxyl and amino groups (amphiprotic groups), but also fast and reversible quinone-hydroquinone proton-coupled electron-transfer reactions, enabling improved capacitive behaviors with respect to areal capacitance, rate capacity, and long cycle lives.