Programmable Diacetylene‐Bridged Cyclotetrathiophenes With Nonplanar π‐Expanded Skeleton for Electrochemical Sodium Storage

Fused aromatic ring systems offer flexibility in molecular‐level design, facilitating programmable redox activity and exhibiting remarkable energy‐storage performance. Nevertheless, the planar backbone structure and strong π–π stacking significantly impede their practical capacity and cycle stability. Herein, we present a novel three‐dimensional (3D) polymer, diacetylene‐linked cyclic tetrathiophene ( 3D‐PTE‐COTh ) with a partial crystalline structure, which is based on the thiophene‐fused [8]cycloene framework and intramolecular acetylene connecting wires. This construction exploits the electrochemically induced micro‐telescopic behavior regulated by Hückel's rule, allowing for dynamic conformational alterations that alleviate π–π stacking effects. Simultaneously, the combination of fused thiophene and graphdiyne‐like linkages improves electronic conductivity and introduces a plethora of electron‐deficient redox‐active sites. As a cathode material, the synergistic sodium storage of the cyclooctatetraene (C 8 ring), ─C≡C─C≡C─ bonds, and fused‐thiophene enables 3D‐PTE‐COTh to achieve a high specific capacity of 347.9 mAh g −1 at 0.5 A g −1 , thereby presenting new prospects for the design of advanced organic electrode materials.