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.