Mn-Incorporated α-Fe2O3 Nanostructured Thin Films: Facile Synthesis and Application as a High-Performance Supercapacitor

Among all the transition metal oxides, iron oxide-based materials are excellent for supercapacitor performance. Here, Mnincorporated alpha-Fe2O3 (Mnm-Fe2O3) nanostructured thin films (with 3%, 5%, and 7% Mn) are prepared via spray pyrolysis. All the synthesized nanostructured thin films are characterized by x-ray diffraction (XRD), optical study, Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and contact angle for the structural, optical, morphological and wettability analysis, respectively. The band gap of Mn:alpha-Fe2O3 nanostructured thin films is tuned by changing Mn concentration. The increasing Mn concentration shifts the valance band edge towards the conduction band edge, reducing the band gap. The linear band gap decrease of 0.44 eV with the addition of Mn concentration, along with the band gap reduction, affects supercapacitive performance. The prepared 7% Mn:alpha-Fe2O3 nanostructured electrode exhibits excellent specific capacitance of 688.6 F g(-1) at a scan rate of 5 mV s(-1) in 1 M Na2SO4 electrolyte, energy density (6 Wh kg(-1)), and power density (12 kW kg(-1)) at a current density of 5 mA g(-1).