Room-temperature facile synthesis of MnO2 on carbon film via UV-photolysis for supercapacitor

A facile UV-photolysis method has been developed to synthesize birnessite-type MnO2 nanosheets on carbon film at room temperature for supercapacitor electrode materials. The results clearly demonstrated that the specific capacitance of carbon/MnO2 composite electrodes was controlled by the adjustable UV-photolysis reaction time in KMnO4 solution. For the optimized composite electrode obtained after 2 h reaction, a superior specific capacitance of 277 F g−1 was achieved at current density of 0.2 A g−1. This finding suggests that UV-photolysis is a potential method to fabricate MnO2 on carbon film for supercapacitor. [Display omitted] •We presented a cost-/time-/operation-effective UV-photolysis method to grow birnessite-type MnO2 on carbon film.•The specific capacitance of carbon/MnO2 electrodes could be adjusted according to the UV-photolysis reaction time.•An optimized gravimetric capacitance of the electrode reached 277 F g-1 at a current density of 0.2 A g-1.•UV-photolysis method could be a promising way to fabricate bind-free MnO2 electrodes for energy storage applications.