Metallosalen Covalent Organic Frameworks with Integrated Organic–Inorganic Active Sites for Enhanced Li Storage

Covalent organic frameworks (COFs) hold great promise as cathode materials for lithium-ion batteries (LIBs), but their limited conductivity has hindered broader application. In this study, a novel metallosalen COF (Cu-TH-COF) is introduced, synthesized via a one-pot method, incorporating redox-active Cu ions into N₂O₂ pockets and creating an extended π-d conjugated structure. This design merges organic and inorganic active sites, enabling efficient multi-electron transfer and improving the utilization of active sites in LIBs. The π-d conjugation significantly enhances the electronic conductivity, resulting in improved rate performance. As a result, Cu-TH-COF delivers an impressive discharge capacity of 300 mAh g⁻¹ at 50 mA g⁻¹ and retains 174 mAh g⁻¹ at 4000 mA g⁻¹, significantly outperforming its Cu-free counterpart. This study demonstrates for the first time the potential of metallosalen COFs as high-performance cathode materials and opens up a new strategy for next-generation LIBs.