Multi-shelled α-Fe2O3 microspheres for high-rate supercapacitors

Hollow structured metal oxides are extensively studied in energy storage and conversion systems. In this work, we report the fabrication of multi-shelled Fe2O3 microspheres with nanospindles assembly on its exterior shell. The beta-FeOOH precursor nanospindles were firstly grown on the surface of carbon microspheres to produce beta-FeOOH@carbon composites, which were later converted into multi-shelled Fe2O3 microspheres by calcination in air. As electrode material for supercapacitors, the multi-shelled Fe2O3 microspheres exhibit high capacity and good rate capability. The electrode delivers the specific capacitances of 630 and 510 F g(-1) at the current densities of 1 and 5 A g(-1) respectively.