Semi-crystalline Conductive Hydrogels for High-Energy and Stable Flexible Supercapacitors

Conductive polymer-based hydrogels (CHs) have gained increasing attention as flexible electrode materials for making high-performance flexible supercapacitors (FSCs). However, the amorphous nature of current CHs severely limits their energy density and electrochemical stability, due to the structural damage of amorphous CHs at high operation voltages and during repeated redox reactions. We hypothesized that semi-crystalline CHs that possess more ordered chemical structure and less defects should be more resistant to structural damage. Herein, we report a soft-template synthesis strategy to prepare semi-crystalline CHs by the supramolecular assembly of poly(3,4-ethylenedioxythiophene) (PEDOT) and polyvinyl alcohol (PVA, serving as a soft template) for making FSCs with higher energy density and better electrochemical stability. In a water/DMSO mixture solvent, semi-crystalline PEDOT nanofibers are formed by oxidative polymerization of EDOT monomer, and in-situ assemble with PVA to form PEDOT-PVA supramolecu...