A Review on In Situ Microscopic Understandings of Dendritic Zinc Growth in Aqueous Zinc Ion Batteries

ABSTRACT Aqueous zinc ion batteries (AZIBs) have garnered significant attention in recent years due to their environmental friendliness, low cost, and high theoretical capacity, positioning them as a highly promising and safe energy storage system. However, under actual battery operating conditions, zinc (Zn) anodes commonly face issues such as uncontrollable electrodeposition and the resulting dendrite growth, which severely hinder the further application and promotion of AZIBs. The key to addressing this bottleneck lies in understanding the nucleation and growth of Zn dendrites, which has been the goal of a substantial amount of recent research reports. This review thus timely summarizes recent findings related to the evolving mechanisms of Zn dendrites in a working AZIB; specifically, it focuses on those revealed by in situ diagnoses via optical and electron microscopy, the combination of which yields multi‐scale observations that sufficiently cover necessary details from Zn nucleation (nanoscale) to the dendritically developing stage (microscale). By summarizing such in situ findings related to electrochemical Zn deposition, this review aims to establish a reliable model to describe the entire developing stage of dendritic Zn deposits, thus paving the theoretical basis for the strategic engineering of the Zn anode for more sustainable AZIBs. image