Freestanding three-dimensional reduced graphene oxide/MnO2 on porous carbon/nickel foam as a designed hierarchical multihole supercapacitor electrode

The optimization of the electrodes structure is crucial for supercapacitors. Herein, we report a novel three-dimensional (3D) hierarchical multihole architecture of ternary reduced graphene oxide (rGO)/MnO2/carbon foam (CF) nanocomposites. Thereinto, CF not only firstly serves as conductive skeleton but also offers primary pore structure with nickel foam and supporter for electrochemical deposition (ECD) of MnO2. Furthermore, rGO covered on electrodes surface both prevents the exfoliation of MnO2 and integrates with it to construct secondary pore structure. The configuration with three components synergistic effects leads to a high specific capacitance of 356.5 F g−1 at a scan rate of 10 mV s−1 and a long cycle life along with 93.6% specific capacitance retained after 2000 cycles. Also, it even remained 30.6 Wh kg−1 at a large power density of 13.5 kW kg−1.