Advance in Electrolyte for Stable Zinc Anodes in Mild Aqueous Batteries

The emerging aqueous zinc-ion batteries (AZIBs) are considered to be one of the promising candidates for large-scale energy storage systems due to their high theoretical capacity, low cost, and eco-friendliness. However, the instability of the zinc metal anode side seriously hinders the practical application of AZIBs. Recently, numerous researchers have focused on improving a series of problems related to the alignment of zinc anodes through electrolyte optimizations. In order to thoroughly and comprehensively understand the underlying mechanisms of these strategies, in this review, the origin of uneven Zn deposition/dissolution and interfacial side reactions of zinc anodes in a mild electrolyte are discussed. Ulteriorly, the research progress and corresponding strategies for improving zinc anodes with electrolytes are summarized, including changing the structure of the solvation sheathing, adjusting the Zn deposition behavior, the in situ solid electrolyte interface protection mechanism, and the interfacial pH buffer. Furthermore, we discuss potential future research directions and key focus areas for overcoming the challenges that AZIBs may encounter in their path toward industrialization.