Electrolyte design for rechargeable anion shuttle batteries

As an emerging new type of battery chemistry, the anion shuttle battery (ASB), based on the shuttling and storage of anions, is considered a sustainable alternative to gigawatt-scale energy storage due to the associated resource abundance, low cost, high safety, and high energy density. Although significant progress has been achieved, practical applications of ASBs are still hindered by tough challenges, such as short lifetime, limited reversible capacity, and low Coulombic efficiency. Therefore, it is very necessary to design and explore new electrolyte systems with high electrochemical/chemical stability, sufficient compatibility towards electrodes, and excellent kinetics/reversibility for anion electrochemical reactions. Here, we review the recent achievements and main challenges in developing electrolytes for ASBs, which include solid, non-aqueous, and aqueous electrolytes. We mainly focus on the unique properties and basic principles of designing these electrolytes, and their various performance parameters. Perspectives on design strategies for ASB electrolytes are also presented, which could facilitate the development of advanced ASBs for grid-scale energy storage.