Fabrication of TiO2@MnO2 nanotube arrays by pulsed electrodeposition and their application for high-performance supercapacitors

The fabrication of TiO 2 @MnO 2 nanotube arrays (NTAs) structure is accomplished via a pulsed electrodeposition technique. The successful preparation of this structure is owing to the high current pulse used, which creates a sufficient nucleation trend on the wall of the entire TiO 2 nanotube layer, that results in the continuous deposition of MnO 2 along the nanotube walls. The synthesized TiO 2 @MnO 2 NTAs sample is found to exhibit excellent electrochemical behavior with high specific capacitance of 425.0 F g −1 and areal capacitance of 150.9 mF cm −2 , ranking in the top level ever achieved by a MnO 2 -TiO 2 composite. Furthermore, a symmetric supercapacitor device is assembled using two strips of the TiO 2 @MnO 2 NTAs electrode that yielded energy density as high as 7.4 Wh kg −1 , a much higher value than most of the values reported for symmetric MnO 2 //MnO 2 supercapacitors. The remarkable electrochemical properties of the TiO 2 @MnO 2 NTAs sample make it an attractive candidate for the application of constructing high-performance supercapacitors.