Step‐Edge Guided Homoepitaxy Enables Highly Reversible Zn Plating/Stripping

Abstract Metal anodes are of profound impact towards the realization of energy‐dense rechargeable batteries. However, the “hostless” metal redox always presents the disordered plating/stripping, aggravated by the side reactions and local anisotropy that cause the formation of excessive dendrites/voids and quickly lead to battery failure. Here we report step‐edge guided homoepitaxy enabling ordered layer‐by‐layer Zn plating/stripping regardless of the (dis)charging conditions. Through engineering the atomic terrace height on the mono‐oriented Zn(0002) foil anodes, both in‐plane and out‐of‐plane epitaxy aligned to the underlying Zn lattice are demonstrated via the favored edge nucleation and strong interfacial interaction driven by the surface/interface energy minimization, achieving the electrochemical homoepitaxy of continuous, submillimeter‐scale Zn(0002) crystal with nearly 100 % theoretical density. Accordingly, we achieve a high Coulombic efficiency of 99.8 %, high depths of discharge exceeding 51 % and 82 % along with record‐high lifetimes of over a thousand and hundreds of hours, respectively, in zinc metal batteries. The breakthrough results provide new insights on the intrinsic metal plating/stripping from the view of reversible homoepitaxy for rechargeable energy‐dense metal batteries.