Fabrication of ternary conducting polymer hydrogel for flexible supercapacitors

Abstract With the increasing demand for portable electronic devices, it is urgent to develop a flexible energy storage system with high performance and good stability. In this paper, a new kind of poly(vinyl alcohol)–polypyrrole–acidified carbon nanotube (PVA–PPy–CNT‐COOH) conductive composite hydrogel was prepared using a freezing–thawing method for fabricating flexible symmetric solid‐state supercapacitors. The PVA–PPy–CNT‐COOH conductive composite hydrogel has a unique three‐dimensional interpenetrating network structure and functional components, endowing the prepared hydrogel with softness, elasticity, compressibility and formability. Furthermore, the influence of feed mode and feeding ratio on hydrogel preparation was explored. According to the optimal experimental process, a flexible symmetric solid‐state supercapacitor with high energy storage capacity and stability was fabricated using PVA–PPy–CNT‐COOH as the electrode. The capacitance change of the supercapacitor was almost negligible when subjected to 50% strain. Even at 70% strain, the retention rate of volume specific capacitance was still about 88%. This study not only provides a preparation method for a new electrode material but also develops a new type of high‐performance and stable flexible symmetric solid‐state supercapacitor, which has potential application prospects in flexible energy devices. © 2025 Society of Chemical Industry.