Pioneering advances in waste-derived catalysts for next-generation zinc-air batteries

Abstract

Zinc–air batteries (ZABs) are increasingly recognized as formidable contenders for advanced energy storage systems due to their high theoretical energy density, cost-effective zinc anodes, and environmental sustainability. Notwithstanding, the commercialization of these technologies is impeded by the sluggish kinetics associated with the oxygen evolution reaction (OER) occurring at the air cathode. This particular challenge has conventionally been addressed by employing expensive noble metal catalysts, including platinum and iridium. The incorporation of these materials significantly escalates both the overall system costs and the associated carbon emissions. In light of this, recent research endeavors have investigated the feasibility of employing waste-derived non-noble metal catalysts as sustainable and economically advantageous alternatives. This examination provides a meticulous evaluation of the latest developments (2019–2025) related to the synthesis, characterization, and efficacy of catalysts derived from industrial byproducts, electronic waste, depleted batteries, and biomass residues. Empirical studies demonstrate that optimized Fe/Co/Ni-based catalysts derived from waste can enhance OER efficiency by up to 40%, prolong ZAB cycle life by exceeding 5000 cycles, and reduce catalyst expenses by up to 50% compared to noble metals. Life cycle assessment (LCA) findings indicate that these methodologies contribute to a reduction in the overall carbon footprint by approximately 25%. Principal synthesis techniques, including Pyrolysis, hydrothermal treatment, and sol-gel processing, are evaluated in terms of efficiency, scalability, and environmental ramifications. Structural and electrochemical properties are scrutinized using advanced methodologies, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) analysis, and in situ spectroscopy. The review also highlights pilot-scale demonstrations and examines AI-driven catalyst design as an innovative approach to this field. Ultimately, the study identifies significant obstacles, including compositional variability, impurity management, and constrained industrial applications, while proposing future trajectories for the development of ZABs guided by circular economy principles. This positions waste-derived catalysts as a feasible avenue for sustainable and scalable energy storage solutions.