Evolution of waste iron rust into α-Fe2O3/CNF and α-Fe2O3/PANI composites as an efficient positive electrode for sustainable hybrid supercapacitor

A green and sustainable approach to recycle the waste iron rust into a valuable α modification of Fe2O3 via simple grinding calcination for application in hybrid supercapacitor is reported. The α-Fe2O3 was coupled with carbon nanofibers (CNFs) conducting polymer, polyaniline (PANI), form composite electrode materials. conventional hydrothermal, electrospinning, in-situ polymerization processes were used prepare composites. Further, X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution (HRTEM), selected area (SAED), scanning (SEM), energy-dispersive x-ray (EDAX) spectroscopy study structural, morphological, compositional properties as-synthesized its composites CNF PANI. α-Fe2O3/CNF α-Fe2O3/PANI composites, coated on rod, as electrodes three-electrode system electrochemical impedance (EIS), cyclic voltammetry (CV), galvanostatic charge–discharge (GCD) 1 M H2SO4. XRD studies revealed formulation modifications an average 28 nm crystallite size. Uniform dispersion over 400–500 diameter excellent covering PANI nanomaterials morphological features observed /CNF /PANI respectively. exhibit higher performance against Fe2O3/CNF respect specific capacitance, 192 Fg−1 (88.88 Fg−1); energy density, 11.28 Whkg−1 (3.084 Whkg−1); power 162 Wkg−1 (69.39 Wkg−1); capacitance retention 80% (75%) after 5000 cycles. heavy long fibers intimate contact resulted abundant active sites reactions leading obtained result. rust-derived offers stability act potential candidate application.