Extreme properties of double networked ionogel electrolytes for flexible and durable energy storage devices

Abstract

Achieving both performances and functionalities of energy storage devices at extreme conditions remains a critical challenge due to the property trade-offs of materials. Here, we demonstrate highly ion-conducting, stretchable, and ultradurable double network (DN) ionogel films, where ionic liquids are confined in chemically-coupled DNs consisting of hard and soft polymers, for high-temperature flexible supercapacitors (hfSCs). Both mechanical and electrochemical integrities at high temperatures are attributed to the unique DN structure and thermally activated ionic transport of the ionogels. Even at 100 degrees C, the DN ionogel film demonstrates remarkable properties, such as the ionic conductivity of 36.8 mS cm(-1), the tensile strength of 1.4 MPa, stretchability of 500%, and dissipation energy of 216 kJm(-3). Thus, the hfSCs achieve the highest energy density of 51.0 Wh kg(-1) at 180 degrees C among previous solid-state SCs, showing extreme durability of 91% over 100,000 cycles and functional hybrid system at both elevated temperatures and bent states.