1-Dimensional porous alpha-Fe2O3 nanorods as high performance electrode material for supercapacitors

Abstract

Porous alpha-Fe2O3 nanorods are successfully synthesized without any templates by a simple wet chemical synthesis method using ferrous sulphate (FeSO4 center dot 7H(2)O) and sodium acetate (CH3COONa) as starting materials. In this method, initially obtained alpha-FeOOH is calcinated at 300 degrees C for 2 h to form 1-dimensional porous alpha-Fe2O3 nanorods. Thermogravimetric analysis (TGA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HR-TEM) and a gas sorption analyzer are employed to characterize alpha-Fe2O3 porous nanorods. Based on the characterization results, a formation mechanism for alpha-Fe2O3 nanorods is proposed. Electrochemical performance of porous alpha-Fe2O3 nanorods is studied using cyclic (CV) voltammetry, galvanostatic charge/discharge measurements and electrochemical impedance spectroscopy (EIS) in aqueous H3PO4, (NH4)(2)SO4 and Na2SO4 electrolytes. Interestingly, the porous alpha-Fe2O3 nanorod-based electrodes exhibit excellent electrochemical performance, which can be attributed to the high surface area induced by the 1-dimensional porous nanorod structures. The rod shape porous structure facilitates the faster faradic reaction toward electrolytes and delivers highest specific capacitance (308 F g(-1)) and an excellent long cycle life (upto 1000 cycles) in H3PO4 electrolyte, demonstrating that the porous alpha-Fe2O3 nanorods can serve as an excellent electrode material for supercapacitors.