Structural, Spectroscopic and Electrochemical Investigation of Co3O4-Modified 4PbO2–Pb Electrode Materials for Lead–Acid Battery Applications

Lead–acid batteries remain promising for large-scale energy storage due to their low cost, robustness, and recyclability. This study investigates the effect of synthesis temperature and dopant content on the structural and electrochemical properties of the xCo3O4·(100 − x)[4PbO2·Pb] where x = 0–30 mol % Co3O4 prepared by melt quenching. Structural, spectroscopic and electrochemical techniques reveal an amorphous undoped matrix and the formation of vitroceramic structures upon Co3O4 addition, with PbO2, PbO, and cobalt-related phases identified. FTIR and EPR analyses confirmed the incorporation of Co2+ and Co3+ species in tetrahedral and octahedral environments, while UV–Vis measurements showed a non-linear variation in optical properties. Electrochemical results demonstrated a composition-dependent response, with 10–20 mol% Co3O4 providing the most favorable performance. In particular, the 20 mol% sample exhibits good short-term electrochemical reproducibility, whereas the 10 and 20 mol% compositions show the best overall combination of electrochemical parameters. These findings demonstrate that controlled Co3O4 incorporation can effectively tailor the structure and electrochemical behavior of lead-based materials for lead–acid battery applications.