Hierarchical Fe2O3 and NiO nanotube arrays as advanced anode and cathode electrodes for high-performance asymmetric supercapacitors

Rational design and fabrication of advanced electrodes with tailored functionality is of great significance for high-performance asymmetric supercapacitors. Herein, we report the preparation of Fe2O3 nanotube arrays and core-branch NiO nanotube arrays directly on carbon paper by using ZnO nanorods as sacrificial templates via similar synthesis process, which works anode and cathode electrodes for the asymmetric supercapacitors. Benefiting from the free-standing nanotube nanostructures, a large number of surface active sites and fast ion diffusion paths, the Fe2O3 and NiO electrodes could achieve the high capacity up to 81.9 mAh g−1 and 119.7 mAh g−1, respectively. Further, an asymmetric supercapacitor is also assembled by using Fe2O3 as anode and NiO as cathode, which shows a high energy density of 48 Wh kg−1 at the power density of 2089 W kg−1. Current research may put a general route for constructing high-performance anode and cathode materials in energy storage devices.