Recent advances in anode design for mild aqueous Zn-ion batteries

Rechargeable aqueous zinc-ion batteries (ZIBs) are promising as a competitive candidate to replace the dominant lithium-ion batteries due to fewer safety concerns, simplified operational conditions, abundant resources, and cost-effectiveness. However, as anode material, zinc metal suffers from the inevitable zinc dendrites growth, hydrogen evolution reaction (HER), and inherent corrosion in aqueous electrolytes, which severely restrict the reliability of ZIBs. To realize the commercialization of ZIBs, various strategies such as the design of protective coating layers, host materials for zinc stripping/plating, and intercalated anode materials, were developed to overcome the inherent limitations of zinc metal. A thorough understanding of the structure-performance relationship is required for the development of efficient anodes for ZIBs. This review aims to provide a comprehensive overview of the research progress of ZIB anodes concerning protective coating layers on zinc surfaces and intercalated anode materials due to different zinc storage mechanisms. First, the limitations of zinc metal anode and intercalated anode materials are summarized. Second, A summary of diverse strategies and advancements in protective coating layers design for zinc anode is presented. Third, the rarely reported intercalated anode materials are also discussed based on their storage mechanisms, materials specifications, and limitations. Finally, the potential research directions and strategies for developing a high-performance anode for ZIBs were proposed to offer insights into future research endeavors.