Mesoporous Polyimide‐Linked Covalent Organic Framework with Multiple Redox‐Active Sites for High‐Performance Cathodic Li Storage

Abstract

Abstract Covalent organic frameworks (COFs) are gaining increasing attention as renewable cathode materials for Li‐ion batteries. However, COF electrodes reported so far still exhibit unsatisfying capacity due to their limited active site density and insufficient utilization. Herein, a new two‐dimensional polyimide‐linked COF, HATN‐AQ‐COF with multiple redox‐active sites for storing Li + ions, was designed and fabricated from a new module of 2,3,8,9,14,15‐hexacarboxyl hexaazatrinaphthalene trianhydrides with a 2,6‐diaminoanthraquinone linker. HATN‐AQ‐COF possessing excellent stability, good conductivity, and a large pore size of 3.8 nm enables the stable and fast ion transport. This, in combination with the abundant redox active sites, results in a high reversible capacity of 319 mAh g −1 at 0.5 C (1 C=358 mA g −1 ) for the HATN‐AQ‐COF electrode with a high active site utilization of 89 % and good cycle performance, representing one of the best performances among the reported COF electrodes.