Recent progress and challenges of Zn anode modification materials in aqueous Zn-ion batteries

Recently, aqueous Zn-ion batteries (ZIBs) have been actively explored and considered as prospective energy storage devices owing to their high safety, low cost, high volumetric capacity (5851 mAh/cm3), and environment-friendly. Nonetheless, the challenges of Zn anodes in aqueous ZIBs must be addressed before realizing commercial utilization. This review starts with a systematic discussion of the sources of dendrites growth and side reactions of Zn anodes, as well as their origin and fundamental mechanisms in aqueous ZIBs. Subsequently, three strategies for modified Zn anodes are carefully discussed (including surface modification, structure design, and alloying anode). Among them, the action mechanisms and modification designing of different kinds of materials including carbon-based material, metal, polymer, inorganic non-metal, hybrid materials, and novel materials like metal–organic frameworks (MOFs), covalent organic frameworks (COFs), and MXene are particularly addressed. Finally, the conclusion and perspectives of modification methods and material designing points are presented for both future studies and commercial applications in the field of aqueous ZIBs.