Recycling of Lead-Acid Battery Electrodes Using Sb₂O₃ and CuO: Characterization and Electrochemical Investigations

The recycling of spent automotive batteries is essential for minimizing their environmental impact. This requires eco-innovative methods with low cost and energy use. The present study explores the recycling of battery electrodes through the melt quenching method, a process that incorporates spent anode and cathode plates into a vitreous host matrix. Samples with the xCuO·10Sb₂O₃·(90 - x)[4PbO₂·Pb] composition, where x = 0 to 30 mol% CuO, were prepared by the melt quenching method. The XRD analysis indicates the vitroceramic structures of the obtained samples. Thus, the presence of varied crystalline phases such as Pb₂(SO₄)O, PbSO₄, and metallic Pb was detected. The SEM micrographs highlighted heterogeneous regions within the samples and showed a decreases of the size of crystallites with increased dopant concentrations. IR and UV-Vis spectra suggest that the copper ions act as network modifiers, creating bond defects and free oxygen ions, and yielding a reduction of the optical bandgap energy at higher dopant contents. EPR data show that the shape of the resonance lines and the coordination geometry of the Cu²⁺ ions are influenced by the dopant concentrations. The analysis of the voltammetric data indicates that doping the recycled material with 20 mol% CuO and 10 mol% Sb₂O₃ eliminates the process of hydrogen evolution and reduces the anodic electrode passivation.