Ionogel Electrolytes for High-Performance Lithium Batteries: A Review

Ionic liquids (ILs) are important electrolytes for applications in electrochemical devices. An emerging trend in ILs research is their hybridization with solid matrices, named ionogels. These ionogels can not only overcome the fluidity of ILs but also exhibit high mechanical strength of the solid matrix. Therefore, they show promise for applications in building lithium batteries. In this review, various types of solid matrices for confining ILs are summarized, including nonmetallic oxides, metal oxides, IL-tethered nanoparticles, functionalized SiO₂, metal–organic frameworks, and other structural materials. The synthetic strategies for ionogels are first documented, focusing on physical confinement and covalent grafting. Then, the structure, ionic conductivity, thermal stability, and electrochemical stability of ionogels are addressed in detail. Furthermore, the authors highlight the potential applications of state-of-art ionogels in lithium batteries. The authors conclude this review by outlining the remaining challenges as well as personal perspectives on this hot area of research.