Aqueous Zinc‐Ion Batteries

Sustainable energy storage, coupled with carbon-negative goals, is vital for the advancement of next generation electrochemical energy storage technologies. In the context of affordable and clean energy storage, rechargeable aqueous zinc-ion batteries (AZIBs) have emerged as an important class of energy storage devices. The high abundance, high theoretical capacity (820 mAh g −1 ), low redox potential (−0.76 V vs. standard hydrogen electrode [SHE]), operational safety, and low toxicity of zinc (Zn) metal anodes make them a promising energy storage solution. ZIBs employ manganese- and vanadium-based oxide cathodes, Zn foil or Zn-powder anodes, aqueous Zn salt electrolytes (such as ZnSO 4 and Zn[CF 3 SO 3 ] 2 ) and glass fiber (GF) or cellulose separators. However, the performance of AZIBs is constrained by several challenges, including the formation of spiky or needle-like Zn dendrites, that damage the separator and cause short circuits, Zn-anode corrosion, undesired side reactions, cathode dissolution, and the hydrogen evolution reaction (HER), collectively leading to battery failure. Therefore, several practical strategies have been developed to overcome these challenges. The robust design of cathodes, dendrite-free Zn-anodes, modified electrolytes, and functional separators paves the way for durable ZIBs. Scalable recyclability, low environmental impact, and better-energy storage performance metrics, highlight the practical significance of ZIB systems for stationary energy storage and other applications.