Research progress of electrolytes for aqueous zinc-ion batteries.

Aqueous zinc-ion batteries (AZIBs) are emerging as promising electrochemical energy-storage systems because of their intrinsic safety, material abundance, and sustainability. Among the key battery components, the electrolyte plays a pivotal role in governing ion transport behavior, interfacial chemistry, and overall electrochemical performance. Nevertheless, traditional aqueous electrolytes are often accompanied by parasitic side reactions, including zinc corrosion, dendritic deposition, and water-induced hydrogen evolution, which undermine cycling stability and reversibility. This review presents a comprehensive overview of recent advances in electrolyte engineering for AZIBs, covering three major approaches: tailoring conventional aqueous electrolytes through concentration and pH regulation, developing advanced electrolyte systems such as gel electrolytes, deep eutectic solvents, and ionic-liquid-based electrolytes, and employing functional additives to regulate zinc deposition and stabilize electrode/electrolyte interfaces. By correlating electrolyte characteristics with electrochemical behaviors, the underlying mechanisms through which electrolyte design influences battery performance are systematically discussed. Furthermore, critical challenges associated with wide-temperature operation, compatibility with high-energy-density cathodes, and scalable manufacturing are analyzed. Finally, future research directions toward practical and high-performance AZIB electrolytes are proposed, offering design principles for accelerating the transition of AZIB technology from laboratory studies to real-world applications.