Proton Conductive Solid Electrolyte with High Transmittance and Temperature Adaptability for Electrochromic Supercapacitor

ABSTRACT Ionogel‐based solid electrolyte (IG‐SE) possesses excellent temperature adaptability and thus can probably satisfy the development of electrochromic supercapacitors (ECSCs), which need to work in a wide temperature range. However, combining both high transmittance and high ionic conductivity properties remains a major challenge in preparing IG‐SE for ECSCs. Herein, a 3D interconnected crosslinked sulfonated polyvinyl alcohol‐graphene oxide (c‐SPVA‐GO) ionic conductive network is designed to develop IG‐SE with both high ionic conductivity and high transmittance. Through introducing graphene oxide (GO) and modulating its aggregation structure, the ionic conductivity of the IG‐SE is effectively improved from 0.49 to 0.91 mS cm −1 . Simultaneously, the transmittance of the IG‐SE based on the crosslinked polymer‐GO composite membrane increased by 14.83 % after microstructure optimization. Using polyaniline (PANI) as electrode material and c‐SPVA‐GO‐based IG‐SE as electrolyte, the fabricated ionogel‐based ECSC (IG‐ECSC) possessed outstanding electrochemical performance in a wide temperature range between −20°C and 80°C. Furthermore, the IG‐ECSC exhibited an ultrahigh coloring efficiency (CE) of 791.93 cm 2 C −1 . This work investigated SEs from both material composition and microstructure modulation, giving a new way for fabricating wide temperature range ECSCs with excellent energy storage and electrochromic performances.