Hydrogen-doping at ambient conditions enhances the pseudocapacitance of H-TiO2@MnO2

Deliberate engineering of the excellent skeleton to support the MnO 2 can facilitate electron transfer and charge distribution, contributing to high-energy/power supercapacitance. Herein, an ambient and cost-effective hydrogen-doped method is innovatively employed to prepare H-TiO 2 nanotube arrays (H-TNTAs), where the MnO 2 grows further in situ. After hydrogenation, the capacitance increases by 40-fold, attributing to the improved conductivity. The H-TNTAs supported MnO 2 provides good pseudocapacitive performance, with a specific capacitance of 430.1 F/g at a discharging current of 300 μAcm −2 . The H-TNTAs@MnO 2 coupled active carbon (AC) in 0.5 M Na 2 SO 4 electrolyte is fabricated as the aqueous asymmetric supercapacitor (ASC). The ASC device displays a high energy density of 43.9 Wh kg −1 at a power density of 550 W kg −1 , with an output voltage of 2.2 V and a superior capacitance stability of 86.7 % (over 5000 cycles). The idea for designing the hydrogenated transition metal oxides can be extended to other high-performance metal oxide electrodes for energy storage devices.