Acceleration of Singlet Oxygen Evolution by Superoxide Dismutase Mimetics in Lithium–Oxygen Batteries

Side reactions caused by reactive oxygen species (e.g., superoxide and singlet oxygen) are limiting factors in the lithium–oxygen batteries (LOBs). Superoxide dismutase mimetics (SODms), which suppress superoxide‐triggered side reactions by accelerating the disproportionation reaction during discharge, are introduced as soluble additives in the LOBs. However, although SODms promote the disproportionation reaction, which is the main pathway for singlet oxygen evolution, the correlation between SODms and singlet oxygen has not been verified. Here, 4‐carboxy‐TEMPO is selected as a representative SODm that effectively promotes the disproportionation reaction and chemically verifies acceleration of singlet oxygen evolution. Furthermore, by using quencher, it is reported that the release of singlet oxygen evolved by the SODm is decreased. Because this study closely examines the relationship between the additives and singlet oxygen, it is believed that this study provides an important reference for the development of additives for the practical application of LOBs. To accomplish high capacity and reversibility in lithium–oxygen batteries (LOBs), it is essential to reduce the cell degradation caused by the reactive oxygen species such as superoxide and singlet oxygen. Superoxide dismutase mimetics (SODm) to reduce superoxide are discussed as additives for LOBs, and close investigation of the relationship between SODms and singlet oxygen is presented.