Enhancing Electrochemical Properties of Vitreous Materials Based on CaO–Fe2O3–Fe–Pb and Recycled from Anodic Plate of a Spent Car Battery

This paper presents a novel approach for the recycling of spent anodic plates from lead-acid batteries through the melt quenching method using iron and calcium oxides and iron powder. The resulting recycled samples, with a 3CaO·5Fe₂O₃·xFe·(92 - x)Pb composition, where x = 0, 1, 3, 5, 8, 10, 15, and 25% mol Fe, were characterized and analyzed in terms of their electrochemical performance. X-ray diffractograms show vitroceramic structures with varied crystalline phases. Analysis of the IR (infrared spectra) data shows a decrease of sulphate units due to doping with iron content. The ultraviolet-visible (UV-Vis) and electron spin resonance (ESR) data reveal the presence of Fe³⁺ ions with varied coordination geometries. Cyclic and linear sweep voltammograms demonstrate that the samples with 8 and 10% Fe exhibit superior electrochemical performance compared to other vitroceramics. The electrochemical impedance spectroscopy measurements indicate that the sample with 8% Fe had lower resistance compared to other analogues and had enhanced electrical conductivity.