Capture and reduction of singlet oxygen via an anthracene-based framework for stable Li-O₂ batteries

Given the increasing global energy demand and rapid advancement of low-carbon technologies, Li-O₂ batteries have attracted considerable attention owing to their exceptionally high theoretical energy density, offering great promise for advanced energy systems. However, the formation of harmful singlet oxygen (¹O₂) in both discharge and charge processes induces parasitic reactions that deteriorate round-trip efficiency and cycling stability. Herein, an anthracene-based covalent-organic framework (AntCOF) is introduced as a highly effective catalyst for the ¹O₂ reduction reaction (SORR) in Li-O₂ batteries. The conjugated porous framework selectively captures electrophilic ¹O₂, enabling effective charge transfer from AntCOF to the empty π* orbital of ¹O₂ and promoting SORR in subsequent discharge processes. This mechanism suppresses ¹O₂ diffusion and mitigates associated side reactions, leading to reduced overpotentials and improved cycling performance when coupled with a RuO₂ catalyst. This work may enlighten further investigations into ¹O₂-related chemistry across a broad range of oxygen-redox electrochemical systems.