Polyoxometalate/α-Fe₂O₃/polyaniline composite: Tailored approaches for high-performance supercapacitors

The need for portable, high-performance electronics that have high power or energy density has increased significantly in recent years. In this work, a composite material was coated on stainless steel that consists of polyoxometalate (POM)/α-Fe₂O₃/polyaniline (PANI) as an electrode material for a symmetric supercapacitor. α-Fe₂O₃ was prepared using starch as a template while PANI was electrodeposited. The physical and chemical characteristics of the modified electrodes were investigated via Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and electrochemical techniques such as cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge[sbnd]discharge (GCD) experiments. In 1 M H₂SO₄, the composite had a specific capacitance of 528 F/g at a current density of 0.2 A/g. In addition, the composite exhibited a high energy density of 73.4 Wh kg⁻¹ at a high-power density of 7.14 kW kg⁻¹ and 91.62 % capacity retention after 10 cycles. The results show that POM/α-Fe₂O₃/PANI is a promising composite electrode for use as a supercapacitor electrode material.