Insights on electrolyte engineering toward aqueous zinc-ion batteries

The pursuit of safety and efficiency in electrochemical energy storage and conversion systems has long been a central theme. Among these systems, aqueous zinc-ion batteries (AZIBs) are considered promising candidates for next-generation energy storage devices due to their high safety, low cost, and high capacity. However, several critical issues associated with Zn2+ ion transport, including dendrite formation and side reactions at zinc (Zn) metal anodes, severely restricted their practical applications. As the “blood” of AZIBs, electrolytes play a crucial role in stabilizing Zn metal anodes by introducing various components or optimizing the liquid environment. Therefore, a comprehensive understanding of electrolyte engineering for AZIBs is of great significance. In this review, the development of electrolytes is first discussed. Then, the roles of electrolytes in AZIBs are summarized based on recent advances, including regulation of the solvation process, optimization of the solid electrolyte interphase layer, and modulation of ionic transport. Finally, perspectives on the further development of electrolytes for AZIBs are provided. This review may offer valuable insights for the design of functional electrolytes for advanced electrochemical energy storage and conversion systems.