Recent strategies for improving the performance of ionic liquids as battery electrolytes

Ionic liquids (ILs) are widely known for their intriguing properties, such as low flammability, high electrochemical stability, etc., and therefore are considered as promising alternatives to conventional organic solvent-based battery electrolytes. Yet, IL-based electrolytes have rarely been used for practical battery applications, mostly due to their high viscosity and limited transport properties. Recent research efforts attempt to overcome these drawbacks by increasing the salt concentration in electrolytes and exploring the addition of solvents in hybrid ILs, as well as designing solvate IL electrolytes. This review aims to briefly discuss these recent strategies adopted with regard to Li-based and other advanced battery systems. This work also outlines the design of novel ILs where the tuneable chemistry of ILs can play a role in providing a pathway to battery applications.