Fully Conjugated Pseudo‐3D Covalent Organic Frameworks With Accelerated Electron Transport for High‐Performance Lithium‐Ion Batteries

ABSTRACT Organic electrodes are promising candidates for sustainable lithium‐ion batteries due to their environmental friendliness and tunable architectures, yet their practical application is hindered by low electronic conductivity and slow reaction kinetics. Here, we report a fully conjugated pseudo‐three dimensional (3D) covalent organic framework (COF) (TB‐COF‐3D‐S) derived from a two‐dimensional (2D) imine‐linked porphyrin‐diacetylene COF via one‐pot high‐temperature sulfurization, which simultaneously converts imine bonds into planar thiazole units and induces diacetylene crosslinking to form a 3D π‐conjugated network. This architecture markedly enhances both electronic and ionic conductivity while providing abundant redox‐active sites. Consequently, TB‐COF‐3D‐S delivers a high specific capacity of 313 mAh g −1 and an energy density of 670 Wh kg −1 at 0.1 A g −1 , excellent rate performance (96 mAh g −1 at 10 A g −1 ), and stable cycling with 0.0035% capacity decay per cycle over 10,000 cycles. Our study highlights the crucial role of 3D full conjugation in promoting rapid charge transport and efficient redox utilization, offering valuable guidance for designing high‐performance organic cathodes.