Facet-Dependent Plating/Stripping Behavior and Crystallographic Evolution during Cycling on Zn Metal Anodes

Abstract

Aqueous zinc metal batteries offer a safe and low-cost option for scalable energy storage; however, their practical reversibility is limited by nonuniform Zn plating/stripping and dendritic growth. Here, Zn single-crystal electrodes exposing well-defined (002), (100), and (101) crystalline facets were used to isolate the role of crystallography in Zn metal cycling. Zn deposition is strongly facet-dependent, forming hexagonal, rectangular/prismatic, and corner-defined morphologies on (002), (100), and (101) facets, respectively. Time-dependent SEM further reveals that Zn growth proceeds via discrete edge- or corner-initiated crystallographic units rather than uniform terrace coverage. During stripping, Zn metal is removed via facet-preserved mesoscopic dissolution domains, leaving geometry-defined pits rather than random corrosion-like features. However, these pits are not preferentially refilled during subsequent plating. Repeated cycling redirects Zn growth to protrusions and roughened regions, causing mossy/dendritic accumulation, mixed-texture evolution, and loss of epitaxial reversibility. These findings highlight the need to control both oriented deposition and poststripping surface reconstruction.