Facile synthesis of iron-doped hollow urchin-like MnO2 for supercapacitors

Hollow urchin-like iron-doped manganese dioxide (Fe-MnO2) architectures were successfully prepared without any template or surfactant via a facile one-step hydrothermal route. Hollow urchin-like Fe-MnO2 architectures were made up of interleaving nanosheets, resulting in porous structures and high specific surface area. The formation mechanism of hollow urchin-like Fe-MnO2 architectures was proposed based on the Ostwald ripening process. When employed as supercapacitor electrode material, hollow urchin-like Fe-MnO2 delivered a specific capacitance of 203.3 F g(-1) at 250 mA g(-1) as well as a good capacity retention of 88.1% after 1000 cycles at 5 A g(-1). Coupled with activated carbon (AC) negative electrode, Fe-MnO2//AC asymmetric supercapacitor (Fe-MnO2//AC ASC) achieved an energy density of 20.2 Wh kg(-1) at a power density of 225 W kg(-1) and 83.8% capacity retention after 1000 cycles at 3 A g(-1), suggesting its potential applications for energy storage.