Abstract: The development of aprotic alkali metal-oxygen batteries has shown promise due to their high theoretical specific energy, which is supported by the exergonic oxygen electrochemistry. However, practical realization of these batteries has been impeded by parasitic reactions that compromise their rechargeability, efficiency, and cycle life. Recent research has identified highly reactive singlet oxygen (¹O₂) as the main cause of degradation, which has led to a focus on understanding and harnessing this reactive species. This review provides a summary of current knowledge on the formation mechanisms of ¹O₂, identifies knowledge gaps that need to be addressed in the future, and discusses the implications of contaminants and battery components for ¹O₂ formation. The review also covers recent advances in deactivating and taming ¹O₂, and explains the mechanisms that underpin these strategies. We conclude with perspectives on the remaining challenges and future research opportunities in the field of ¹O₂-related (electro)chemistry in metal-oxygen batteries.

Key words: Singlet oxygen, Metal-oxygen batteries, Reactive oxygen species, Lithium-oxygen batteries, Physical Quencher