Facile synthesis of single crystalline mesoporous hematite nanorods with enhanced supercapacitive performance

α-Fe₂O₃ nanorods with a length of 400-700 nm and a diameter of 20-80 nm, which have single-crystalline and mesoporous structure, could be obtained from these α-FeOOH precursors after calcining at 300 °C in air. The as-prepared single-crystalline mesoporous α-Fe₂O₃ nanorodes exhibited a large specific surface area and porosity, effectively increasing the contact area between the electrode materials and electrolyte, minimizing both the ionic and electronic transportation in the Fe₂O₃ during the charge-discharge process. The porous nanostructure facilitates the faster faradic reaction toward electrolytes and delivers highest specific capacitance (534 F g^-1) and an excellent long cycle life (upto 1500 cycles) in 1 M KOH electrolyte at current density of 4 A g^-1, demonstrating that the porous α-Fe₂O₃ nanorods can serve as an excellent electrode material for supercapacitors. It is believed that the single-crystalline mesoporous α-Fe₂O₃ nanorods are beneficial to the charge transfer in the electrode and to the ion transport in the solution during redox reaction.