Design and synthesis of H-TiO₂/MnO₂ core–shell nanotube arrays with high capacitance and cycling stability for supercapacitors

Constructing hybrid electrodes with pseudocapacitive materials is an efficient strategy to realize high capacitance in supercapacitors for many high-energy applications ranging from portable electronics to consumer devices. However, as a typical pseudocapacitive electrode material, MnO₂ usually suffers from poor electronic and ionic conductivities, which hinders the realization of their achievable pseudocapacitances. Comparing with conventional noble metals, cost-effective and robust hydrogenated TiO₂ nanotube arrays are an excellent scaffold to support pseudocapacitive materials due to enhanced ion and electron delivery. Benefit from the structural and electronic advances, the well-designed H-TiO₂/MnO₂ NTAs supercapacitor exhibits specific capacitance as high as ~803 F g⁻¹ at the scan rate of 5 mV s⁻¹, reveals ~88% of the initial capacitance after 20000 cycles (only 0.0006% loss per cycle) and shows a high-rate capability. The well-performed designer could be a promising candidate for future power sources in a wide range of applications.