MnO2 nanorod loaded activated carbon for high-performance supercapacitors

Abstract

Nowadays, transition metal oxides (TMOs) have gained much attention as potential candidates for supercapacitors owing to their remarkable properties for instance vast abundance, a high value of theoretical capacitance, easy accessibility, and eco-friendly nature. But low electric conductivity of TMOs restrains them from reaching their theoretically predicted value for capacitance. Activated carbon with enormous surface area and excellent conductivity has been chosen to augment the conductivity of TMO-based electrodes. Here in this paper, we have synthesized MnO 2 nanorods via a facile hydrothermal process. These nanorods have been loaded onto activated carbon via a straight-forward sol-gel approach at room temperature. The obtained nano-composite exhibited superior capacitance of 398.5 F g −1 at 1 A g −1 than MnO 2 (161.8 F g −1 ). The composite attained excellent energy of 105.2 Wh kg −1 (at 2 kW kg −1 ). Further, the composite was tested for device application. Three symmetric supercapacitor cells joined in series were proficient to glow a blue LED for about one minute while the red LED was illuminated for about 12 min. This suggested that the composite material has broad potential applicability as supercapacitor electrode material. • Low cost and eco friendly MnO 2 /AC composite has been synthesized by straight-forward sol-gel approach at room temperature. • The composite exhibited high specific capacitance of 398.5 F g −1 at 1 A g −1 in a two electrode system. • High energy density of 105.2 Wh kg −1 is achieved at power density of 2 kW kg −1 . • The fabricated device was able to illuminate blue LED for about 1 min and a red LED for about 12 min.