Insight into the development of electrolytes for aqueous zinc metal batteries from alkaline to neutral

Aqueous zinc metal batteries are considered as promising candidates for next-generation electrochemical energy storage devices, especially for large-scale energy storage, due to the advantages of high-safety, high energy density and low cost. As the bridge connecting cathode and anode, electrolyte provides a realistic operating environment. In alkaline and neutral aqueous zinc metal batteries, issues associated with electrolyte and anode are still intractable. In this review, we reveal the development and evolution of electrolytes for aqueous zinc metal batteries from alkaline to neutral via the description of fundamentals and challenges in terms of comparison and connection. We also elaborate the strategies in electrolytes regulation and highlight the basic roles and progresses in additives engineering.