Polyimide covalent organic frameworks as pseudocapacitor electrode materials for stretchable supercapacitors

To meet the growing needs of flexible and wearable electronics, stretchable energy storage devices—especially supercapacitors (SCs)—have become a key focus in advanced energy storage research. However, achieving both mechanical stretchability and high capacitance in SC still faces great challenges, and the crucial factors lie in creating superior electrode materials that exhibit high electrochemical performance as well as excellent mechanical stretchability. Covalent organic frameworks (COFs) possess considerable potential as electrode materials for SCs by virtue of stable organic frameworks, open channels and designable functional groups. Nevertheless, their applications in flexible SCs are greatly hindered by their rigid characteristics. Here a novel COFs@conductive polymer hydrogels (CPHs)@poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) complexes, which integrate the pseudocapacitance of PDI-TAPA COF, mechanical stretchability of hydrogels and high conductivity of PEDOT:PSS, has been developed as stretchable electrode of SCs. Physically cross-linked PEDOT nanofibers, with their interlinked and entangled architecture, collectively boost mechanical, electrical, and electrochemical performance. The COFs@CPHs@PEDOT:PSS simultaneously demonstrates outstanding mechanical stretchability, high electrical behaviors, and superior swelling characteristics. The resulting SC exhibits advantages of simple structures, facile assembly processes, high specific capacitance, excellent cycling stability, and arbitrary deformation, which holds great application prospects for wearable electronic products. Owing to its uncomplicated structure, ease of production, high energy storage capacity, robust cycling performance, and adaptability to deformation, this fabricated SC is well-suited for next-generation wearable technologies.