Protective Layer Derived from Garlic for Stable and Dendrite-free Zinc Metal Anodes of Rechargeable Batteries

Zinc (Zn) metal is a promising anode material for large-scale energy storage systems due to its intrinsic safety and cost-effectiveness. However, uncontrolled Zn2+ deposition often leads to dendritic growth, which can pierce the separator and compromise the cell performance and safety. To address this challenge, we report the design of a three-dimensional (3D) long-range functionalized separator incorporating sulfur-containing compounds. The presence of surface-bound sulfur atoms promotes uniform Zn2+ flux and guides ion transport, leading to a more homogeneous electric field at the anode–electrolyte interface. This facilitates controlled Zn nucleation and a smooth deposition behavior. When paired with a thermodynamically stable and intrinsically safe triethyl phosphate (TEP)-based electrolyte, Zn||Zn symmetric cells employing this ″garlic-derived″ separator demonstrate exceptional cycling stability for over 4,000 h at 1.0 mA cm–2 and 1.0 mAh cm–2. Furthermore, stable operation is achieved at current densities as high as 3.0 mA cm–2 with a high Coulombic efficiency of ∼99%. The strong affinity between the organosulfur groups and the electrolyte enhances interfacial wettability, thereby promoting a uniform Zn2+ flux through the solid electrolyte interphase (SEI) and contributing to the excellent electrochemical performance.