Corrosion Mechanisms and Mitigation Strategies during Electrochemical Discharge of Spent Lithium-Ion Batteries

Abstract The discharging of spent lithium-ion batteries (LIBs) is a critical pretreatment step in the recycling process, as it minimizes the risk of short circuits, thermal runaway, and fire, thereby ensuring operational safety. However, the battery discharge process frequently induces corrosion of metallic components, which could lead to structural degradation and the potential leakage of toxic electrolytes. In this study, we discuss the underlying corrosion mechanisms that occur during electrochemical discharge of spent LIBs in various electrolyte systems. This discussion consolidates current knowledge on corrosion pathways, the environmental impacts of electrolyte degradation, and mitigation strategies, including inhibitor addition, external isolation, and low-chloride smart solvents. We also outline different metrics and quantitative corrosion characterization approaches. These methods are essential for comparing discharge media and determining whether rapid electrical discharge is achieved at the expense of battery casing, terminal, or current collector degradation. Finally, we outline future directions for developing safer discharge media to enable low-corrosion and environmentally sustainable LIB recycling.