Recent developments of nanocomposite ionogels as monolithic electrolyte membranes for lithium-based batteries

Abstract

To utilize intermittent renewable energy to achieve carbon neutrality, rechargeable lithium-based batteries have been deemed to be the most promising electrochemical systems for energy supply and storage. However, there still exist safety issues and challenges, especially originating from the intrinsic volatility and flammability of the electrolytes used in lithium-based batteries. Due to the unique advantages of better safety, (quasi) solid-state electrolytes have been exploited. Ionogel (IG), known as ionic liquid (IL) based monolithic quasi-solid-state electrolyte separator, consists of IL and gelling matrix and has become an active area of research in lithium-based battery technology, owing to fascinating exotic characteristics including high safety (thermal stability) under extreme operating conditions, wide processing compatibility, and decent electrochemical performances. Among various gelling matrices, nanomaterials are very promising to simultaneously enhance ionic conductivity, mechanical strength, and thermal and electrochemical properties of IGs, which make the nanocomposite ionogels (NIGs). Herein, several significant advantages of NIGs as monolithic electrolyte membranes are briefly described. Also, recent advances in the NIGs for Li-ion batteries, Li-metal batteries, Li-S batteries, and Li-O₂ batteries are timely and systematically overviewed. Finally, the remaining challenges and perspectives on such an interesting and active field are discussed. To the best of our knowledge, there are rare review articles focusing on the NIGs for Li-based batteries till now. This work could offer a comprehensive understanding of recent advances and challenges of NIGs for advanced lithium storage.