Microscopic Insights into Zn (002) Epitaxial Electrodeposition in Aqueous Zinc Metal Batteries

Dendrite growth, corrosion, passivation, and other side reactions during Zn plating and stripping have consistently hindered the capacity and lifespan of Zn metal batteries. In this study, we employ first-principles calculations to unravel the epitaxial electroplating mechanism of Zn (002) planes on various substrate surfaces. We identify six critical factors, including interfacial stability, zincophilicity, surface atomic arrangement, lattice mismatch, responsiveness, and adaptability, that profoundly influence the electrochemical behavior of zinc deposition. Our findings reveal that substrates with hexagonal surface atomic arrangements and strong metallic bonding with zinc, such as (002)-Zn, (111)-Cu, and Ti₃C₂ MXenes, facilitate uniform and dendrite-free zinc deposition. Notably, lattice contraction induced by substrate lattice mismatch exerts a greater impact on the deposition stability than lattice expansion. Kinetic analyses demonstrate that substrates exhibiting high responsiveness and adaptability can tolerate higher current densities and larger areal capacities, which are crucial for practical applications.