Ionogels: From Properties and Synthesis to Toughening, Patterning, and Applications

Ionogels, an emerging branch of gels, are polymer networks swollen with ionic liquids. Ionogels are nonvolatile and possess ionic conductivity as well as high thermal and electrochemical stability. These fascinating features make ionogels extremely attractive in many fields, such as wearable and flexible electronics, energy storage devices, and sensors. Yet, ionogels usually suffer from poor mechanical properties, which severely limits their applications. To solve this problem, a lot of effort has been devoted to improving ionogels. Here, we present a review mainly focusing on the toughening mechanisms of ionogels, given the critical role of mechanical behaviors in their applications. Meanwhile, the physicochemical properties, synthetic strategies, patterning methods, and applications of ionogels are considered. We hope this review will not only inspire further research but also provide guidance for the rational design of tough ionogels, thereby broadening their potential.