Triazine‐Based Large‐Sized Single‐Crystalline Two‐Dimensional Covalent Organic Framework for High‐Performance Lithium‐Ion Batteries

A large‐sized single crystalline 2D COFs with excellent crystallinity and stability was prepared through the traditional thermal solvent method. The electrochemical performance can be significantly enhanced using a straightforward hybrid approach that involves in situ growth of the 2D COFs on multi‐walled carbon nanotubes (MWCNTs). Both the advantages of COFs and CNTs are mutually enhanced. The single‐crystalline feature of the obtained COFs improves the structural integrity and brings excellent chemical and electrochemical stabilities for lithium‐ion battery applications. The resultant COF‐CNT core–shell hybrids greatly improved the conductivity and demonstrated excellent lithium‐ion storage performance with a high capacity of 228 mAh g−1 (0.2 A g−1). A large‐sized single‐crystalline 2D COFs with enhanced structural integrity and exceptional chemical and electrochemical stability was prepared. Through a simple composite process with CNTs, the resultant COF‐CNT core–shell hybrids exhibit outstanding performance as lithium‐ion storage materials in lithium‐ion batteries.