Insights on electrolytes engineering towards aqueous zinc ion batteries

The pursuit of safety and efficiency in electrochemical energy storage and conversion systems has always been a constant theme. Among which, aqueous zinc ion batteries (AZIBs) are ideal candidate for the next-generation energy storage devices attributed to high safety, low cost as well as high capacity. Nevertheless, some critical issues related with Zn²⁺ ions transport including dendritic formation and side reactions on zinc metal anodes severely restricted their practical applications. As the blood of AZIBs, electrolytes play crucial roles in the stabilization of zinc metal anodes by introducing various components or optimizing the liquid environment. Therefore, a comprehensive understanding of electrolytes engineering towards AZIBs is of great significance. Herein, the development of electrolytes is firstly discussed. Then, the roles of electrolytes for AZIBs are reviewed based on recent advances, including regulating the solvation process, optimizing the structure of the solid electrolyte interphase (SEI) layer and modulating ionic transport. Finally, some perspectives toward the further development of electrolytes in AZIBs are provided. This review may offer some inspiration for designing functional electrolytes for advanced electrochemical energy storage and conversion systems.