Metal-Organic Hybrid Material with Polar Covalent Bonds as a Protective Layer for Zn Anodes in Aqueous Zinc Batteries

Abstract

Aqueous zinc batteries are promising candidates for safe, low-cost energy storage, yet their practical deployment is limited by dendrite growth, hydrogen evolution, and poor interfacial stability. Here, we report a polar-covalent metal–organic hybrid coating, termed Zincone–PC, that stabilizes Zn metal anodes by combining hydrolytic durability with directional ion transport. The Zincone–PC, synthesized via molecular layer deposition, consists of vertically aligned (–Zn–S–hydroquinone–O–)n chains, where polar ZnS bonds provide water resistance and facilitate Zn2+ conduction through an ionic hopping mechanism. Spectroscopic and structural analyses confirm strong vertical ordering and chemical integrity in aqueous media. Zincone–PC enables stable Zn plating/stripping over 550 cycles at 1 mA cm−2 with nearly 100% Coulombic efficiency. In full cells, it delivers 86% capacity retention after 200 cycles at 0.5 C and maintains 19% at 2 C, demonstrating excellent long-term stability and rate capability. This work establishes a molecularly engineered strategy for interfacial stabilization in high-rate, long-life aqueous Zn batteries.