An Overview of Electrocatalysts Derived from Recycled Lithium-Ion Batteries for Metal–Air Batteries: A Review

Waste lithium-ion batteries (LIBs), which usually contain dangerous organic electrolytes and transition metals, including nickel, cobalt, iron, and manganese, can hurt the environment and human health. Substantial advancements have been achieved in employing high-efficiency, economical, and environmentally sustainable techniques for the recycling of spent LIBs. Converting exhausted LIBs into efficient energy conversion catalysts straightforwardly is a good strategy for addressing metal resource constraints and clean energy concerns. This transforms waste cathodes, anodes, binders, and separators from depleted LIBs into electrocatalysts free of platinum group metals for the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR). The composite, including transition metal oxide, graphene oxide, and carbon mass, will be synthesized from spent LIBs, demonstrating enhanced electrocatalytic activity. Utilizing “waste-to-energy” methods for used LIBs as catalysts would provide substantial benefits in environmental preservation and the effective production of functional materials in metal–air batteries.