π-Bridge Linked Ionic Covalent Organic Framework with Fast Reaction Kinetics for High-Rate-Capacity Lithium Ion Batteries.

Covalent organic frameworks (COFs) have emerged as promising cathode materials for high-performance lithium-ion batteries (LIBs) due to their well-defined topologies and tunable pore architectures. However, their practical application is often limited by intrinsically sluggish charge transfer and inferior reaction kinetics. To address these challenges, we develop an ionic quinoline-linked COF (iQCOF) cathode via a one-pot Povarov reaction with triazole ionic liquid. The iQCOF architecture achieves a synergistic enhancement by integrating π-bridge-induced charge delocalization to facilitate charge transport, the specific adsorption effect to gain fast ionic atmosphere dissociation rate, and polar triazine units to enable uniform ion flux for stable interfaces. As a result, iQCOF delivers a high specific capacity of 407 mAh g-1 with 701 Wh kg-1, and exceptional rate capability (121 mAh g-1 at 10 A g-1) with 0.0027% per cycle over 10000 cycles, further highlighting its potential as a high-performance organic cathode. This work provides a convenient strategy for advanced COF-based cathodes with fast reaction kinetics for high-rate performance, paving the way for next-generation energy storage technologies.