Self-Passivation of Oriented Zn (101) Plating Via Dangling Bond Saturation and Electrostatic Regulation for Achieving High-Utilization and Fast-Kinetics Zinc Anodes

Zn ion batteries (ZIBs) with mild aqueous electrolytes (e.g., ZnSO 4 ) have emerged as promising candidates for grid-level energy storage owing to their high theoretical capacity (820 mAh g -1 ), abundant resources, and environmental compatibility. However, uncontrolled Zn dendrite growth, the hydrogen evolution reaction (HER), and corrosion severely limit the reversibility and lifespan of ZIBs. These challenges become even more critical in practical applications, where a negative/positive (N/P) capacity ratio below 1.08 is required, similar to that of commercial lithium-ion batteries (LIBs). The morphology of plated Zn, predominantly dictated by the crystallographic (002), (100), and (101) facets of hexagonal close-packed (hcp) Zn, is closely linked to the Zn stripping/plating behaviors and the occurrence of side reactions. According to the Gibbs–Curie–Wulff theorem, the (002) facet exhibits lower surface energy, which translates to reduced reactivity with water and a slower growth rate compared to the (001) and (101) facets. Consequently, orienting the plated Zn along the (002) plane could mitigate dendritic growth, HER, and corrosion, thereby improving the Zn utilization rate (ZUR). Nevertheless, the slower deposition kinetics of Zn (002) relative to Zn (100) and (101) result in increased polarization during cycling, which can adversely affect overall battery performance. Additionally, the (002) orientation is prone to deviation and significant lattice distortion due to the weak bonding between this facet and the deposited Zn atoms, further undermining structural integrity and efficiency. This study aims to leverage the favorable kinetics and stronger Zn–Zn bonding characteristics of the Zn (101) facet to develop sustainable, long-lasting Zn battery applications. Two primary hypotheses were formulated: (a) selective orientation of Zn, specifically the (101) facet, can be achieved by saturating the Zn dangling bonds on this surface; and (b) the highly reactive Zn (101) can be spontaneously passivated by isolating it from direct water contact through an artificial interphase that facilitates rapid Zn 2+ diffusion and provides electron shielding. These hypotheses build on the understanding that (1) dangling bonds are directly associated with surface energy, which elevates the nucleation energy barrier and thereby limits crystalline phase growth, and (2) the plating location of Zn 2+ is governed by ion diffusion and electron reduction. The rapid diffusion of Zn 2+ , coupled with constrained electron availability, may prevent Zn 2+ reduction at the interphase, allowing ions to migrate until they reach an electron source—namely, the underlying Zn electrode—where plating occurs. Herein, we demonstrate reversible Zn 2+ plating along the (101) orientation beneath a SnO 1.17 interphase, achieved by precisely controlling the oxygen ratio in the Sn–O system. This approach selectively saturates the dangling bonds on Zn (101), promotes built-in electrostatic interactions, and reduces the Zn 2+ migration barrier, thus decreasing the surface energy of the Zn (101) facet and facilitating its preferential growth. Moreover, plating Zn (101) beneath the SnO 1.17 interphase prevents direct contact between the highly reactive Zn surface and water, effectively eliminating HER and corrosion. As a result, sustainable Zn 2+ plating/stripping is enabled, ensuring superior reversibility under high current densities and high ZUR conditions. The Zn anode modified with the SnO 1.17 interphase exhibits stable cycling for over 600 hours at 20 mA cm -2 and 20 mAh cm -2 (nucleation overpotential of 72 mV) and 800 hours at a high ZUR of 91.5% (nucleation overpotential of 43 mV). For full-cell performance evaluation, the modified anode was paired with sulfur, MnO 2 , and ZnMn 2 O 4 cathodes. Commercial Zn foil (40 μm) was used for high plating/stripping tests, ultrathin Zn foil (2.8 μm) for low N/P ratios, and Cu foil for an anode-free configuration. The SnO 1.17 -modified anode demonstrated capacity retentions of 95.2% and 77.4% when paired with PEDOT@S and MnO₂ cathodes after 600 and 400 cycles, respectively. Notably, in an anode-free system, the SnO 1.17 -modified anode retained 81.6% of its initial capacity after 200 cycles in the ZnMn 2 O 4 ||SnO 1.17 @Cu configuration, substantially outperforming the 30.9% retention observed in the ZnMn 2 O 4 ||SnO 1.92 @Cu cell. This work was supported by the US National Science Foundation, Award numbers CBET-2207302. [1] Y. Zhang, M. Kim, and S. Lee, Energy Environ. Sci., 2025, doi.org/10.1039/D4EE05498A [2] D. H. Lee, Y. Zhang, and S. Lee, ACS Appl. Mater. Interfaces 2022, 14, 48, 53999–54011, doi.org/10.1021/acsami.2c15719 [3] D. H. Lee, and S. Lee, ACS Appl. Mater. Interfaces 2021, 13, 46, 55676–55686, doi.org/10.1021/acsami.1c16222 Figure 1