Hierarchical TiO2 nanobelts@MnO2 ultrathin nanoflakes core-shell array electrode materials for supercapacitors

Hierarchical TiO2 nanobelts@MnO2 ultrathin nanoflakes core-shell arrays (TiO2@MnO2 NBAs) have been fabricated on a Ti foil substrate by hydrothermal approach and further investigated as the electrode for a supercapacitor. Their electrochemical properties were examined using cyclic voltammetry (CV), galvanostatic charge-discharge, and electrochemical impedance spectroscopy (EIS) in a three-electrode cell. The experimental observations clearly show that the fabricated TiO2@MnO2 NBAs electrode possesses superior rate capability and outstanding cycling performance due to its rationally designed nanostructure. A specific capacitance as high as 557.6 F g(-1) is obtained at a scan rate of 200 mV s(-1) (454.2 F g(-1) at a current density of 200 mA g(-1)) in 1 M Na2SO4 aqueous solution. The energy density and power density measured at 2 A g(-1) are 7.5 Wh kg(-1) and 1 kW kg(-1) respectively, demonstrating its good rate capability. In addition, the composite TiO2@MnO2 NBAs electrode shows excellent long-term cyclic stability. The fabrication method presented here is facile, cost-effective and scalable, which may open a new pathway for real device applications.