Facile Preparation of Hybrid Films Based on MnO2 and Reduced Graphene Oxide for a Flexible Supercapacitor

Supercapacitors (SCs) have drawn considerable attention as one of the energy storage devices. The key to fabricating flexible supercapacitors lies in the acquirement of flexible electrodes. In this study, the manganese oxide (MnO 2 ) and reduced graphene oxide (RGO) hybrid films (MnO 2 /RGO) were prepared by a filtration deposition and thermal reduction technique. Electrochemical measurements show that the hybrid films exhibit a specific capacitance of 333.9 F g −1 at 0.5 A g −1 , and 87% capacitance after 3000 cycles at 0.5 A g −1 . The flexible symmetric SCs was further fabricated with two pieces of MnO 2 /RGO hybrid films as electrodes. The fabricated flexible and sandwich type symmetrical SCs exhibited a safe working range with a potential window of 0–0.7 V with a maximum energy density of 23.5 Wh kg −1 at 0.5 A g −1 and the maximum power density of 1716.9 W kg −1 at 2.25 A g −1 .