Porous α-Fe2O3 Hollow Rods/Reduced Graphene Oxide Composites Templated by MoO3 Nanobelts for High-Performance Supercapacitor Applications.

ABSTRACT

Porous α-Fe2O3 hollow rods/reduced graphene oxide (α-Fe2O3 HR/RGO) composites with unique morphological characteristics and a high surface area are prepared through a template strategy, which was systematically studied and found to have outstanding supercapacitive properties. When served as active material in a three-electrode setup, the optimized α-Fe2O3 HR/RGO-30, comprised 76.5 wt% α-Fe2O3 and 23.2 wt% RGO, was able to offer the largest specific capacitance of 426.3 F g-1, an excellent rate capability as well as satisfactory cycle life with capacitance retention of 87.7% and Coulombic efficiency of 98.9% after continuously charging/discharging at 10 A g-1 for beyond 10,000 cycles. Such electrochemical behaviors of the α-Fe2O3 HR/RGO-30 electrode can rival or even surpass those of many Fe2O3-based electrodes documented in the previous literature. Later, a symmetric supercapacitor cell of α-Fe2O3 HR/RGO-30//α-Fe2O3 HR/RGO-30 was fabricated. The assembled device offers the maximum energy density of 18.7 Wh kg-1, and also exhibits commendable rate capability, and features stable cycling durability (with capacitance retention of 83.2% together with a Coulombic efficiency of 99.3% after 10,000-cycle charge/discharge at 5 A g-1). These notable electrochemical performances enable the α-Fe2O3 HR/RGO-30 composite to be a high-potential material for advanced energy storage systems.