Advancements in ion regulation strategies for enhancing the performance of aqueous Zn-ion batteries

Aqueous Zn-ion batteries (AZIBs) are considered as the emerging energy storage devices due to their high safety and economic value. Their widespread application is, however, hindered by challenges arising from unwanted side-reactions, such as dendrite formation, hydrogen evolution reactions (HER), and corrosion. These issues are closely linked to the Zn 2+ ion solvation sheath, migration, desolvation, and deposition behaviours. Despite significant advances in Zn 2+ ion regulation strategies are used to address these challenges, a deeper understanding of how to design state-of-the-art Zn-ion-batteries through the optimization of the anode, electrolyte, and separator is still needed. This review begins with an overview of the historical development and summarizes the mechanisms behind the challenges faced in AZIBs. It then provides a critical review of recent advances in ion regulation strategies, such as adjusting electrolyte/electrode interface wettability , optimizing crystal orientation , modifying separators, and engineering electrolytes. Finally, the review offers a forward-looking perspective on advancing these energy storage devices for practical industrial use. The insights presented are expected to guide the natural development of other types of active metal-ion batteries.