Side‐Chain Modulation in Diketopyrrolopyrrole‐Based Covalent Organic Frameworks for Fast and Durable Lithium‐Ion Batteries

Abstract

ABSTRACT The development of high‐performance anode materials is essential for next‐generation rechargeable batteries. Herein, a series of pyrene‐linked diketopyrrolopyrrole (DKP)‐based covalent organic frameworks (COFs) is reported through systematic side‐chain engineering using methyl and ether functionalities. A stepwise synthetic strategy employing unsubstituted, methylated, and ether‐functionalized DKP monomers enabled precise tuning of pore environments, ion coordination, and electrochemical behavior. Among these materials, the ether‐modified Py‐DKPOMe COF exhibited outstanding lithium storage performance, delivering an initial reversible capacity of 265 mA h g − 1 and retaining over 100 mA h g − 1 at an ultrafast 20C rate, with 60 mA h g − 1 maintained at 25C. Remarkably, it achieved 80% state of charge within 61.7 s and exhibited excellent long‐term cycling stability, while the high lithium‐ion diffusion coefficient (7.12 × 10 −10 cm 2 s −1 ) confirmed the rapid ion transport facilitated by the ether‐functionalized chains. Interestingly, density functional theory (DFT) and nudged elastic band (NEB) calculations revealed enhanced Li + adsorption affinity and reduced migration barriers in Py‐DKPOMe COF. In addition, Py‐DKPOMe COF also demonstrated promising sodium‐ion storage (138 mA h g − 1 ). Full‐cell tests with a Li‐rich LNMO cathode verified its practical applicability, highlighting molecular‐level COF design as a powerful strategy for fast, durable organic electrodes.