Light-Induced Alternating Catalysis on Single-Atom Ruthenium Embedded in Covalent Organic Frameworks for...

The development of high-efficiency cathode catalysts is crucial for advancing photo-assisted non-aqueous lithium-oxygen (Li-O₂) batteries, which leverage solar energy to reduce the high overpotential for driving oxygen reduction and evolution processes. However, the state-of-the-art photo-cathode catalysts often lack multi-step conversion pathways that regulate interactions between complex active sites and reactive oxygen-related intermediates within Li-O₂ battery systems. Herein, we report a new light-induced alternating catalytic mechanism based on a single-atom Ru-embedded covalent organic framework assembled from a triazine-core C3-symmetric node and π-extended perylene-diimide linkers (T-PDI), generating an ordered conjugated Ru/T-PDI network that functions as a high-performance photo cathode of the Li-O₂ battery. Unlike conventional photo-assisted catalysts that operate through the single-site activity, the Ru/T-PDI electrode enables dynamic migration and efficient conversion of reactive oxygen species between catalytic sites across multiple selective sites. This mechanism orchestrates the multi-step transformation process within Li-O₂ batteries, significantly enhancing catalytic efficiency of active sites and facilitating both the formation and decomposition of Li₂O₂ products. As a result, the photo-assisted Li-O₂ battery employing the Ru/T-PDI cathode achieves a quite low overpotential, outstanding cycling stability and excellent rate performance. This work provides crucial insights for reaction mechanism studies and catalyst design for next-generation light-driven metal-oxygen batteries.