Roadmap on Ionic Liquid Electrolytes for Energy Storage Devices

Ionic liquids are considered to be promising electrolyte solvents or additives for rechargeable batteries (i. e., lithium-ion batteries, sodium-ion batteries, lithium-sulfur batteries, aluminum-ion batteries, etc.) and supercapacitors. This is related with the superior physical and electrochemical properties of ionic liquids, which can influence the performance of rechargeable batteries. Therefore, it is necessary to write a roadmap on ionic liquids for rechargeable batteries. In this roadmap, some progress, critical techniques, opportunities and challenges of ionic liquid electrolytes for various batteries and supercapacitors are pointed out. Especially, properties and roles of ionic liquids should be considered in energy storage. Ionic liquids can be used as electrolyte salts, electrolyte additives, and solvents. For optimizing ionic liquid-based electrolytes for energy storage, their applications in various energy storage devices should be considered by combing native chemical/physical properties and their roles. We expect that this roadmap will give a useful guidance in directing future research in ionic liquid electrolytes for rechargeable batteries and supercapacitors.