Establishing an Ion‐Sieving Separator by Depositing Oxygen‐Deficient SiO_x Layer for Stabilized Zinc Metal Anode

Abstract Stable plating/stripping of Zn metal anode remains a great challenge owing to uncontrollable dendrite growth and side reactions. Ion‐sieving separators is a unique and promising solution, that possess Zn²⁺ permeability and promote Zn²⁺ transport, can effectively alleviate the abovementioned problems. Ion‐sieving on glass fiber separator by deposition of oxygen‐deficient SiO_x layer via active screen plasma technology is achieved. While having chemical composition similar to the glass fiber, the SiO_x nanoparticles contain oxygen‐rich vacancies that promoted dissociation of the adsorbed water and generation of the hydroxyl groups. The negatively‐charged hydroxylated SiO_x layer can repel SO₄²⁻ and attract Zn²⁺, which can alleviate the side reactions. The strong interplay between hydroxyl groups and Zn²⁺ can boost Zn affinity and yield fast Zn²⁺ transport. Consequently, the SiO_x‐deposited GF separator enabled dendrite‐free Zn deposition morphology, which displays lower overpotential of 18 mV and longer cycling life over 2000 h for Zn symmetric cell. Such a separator can also be easily scaled up to prepare the high‐performance large‐area (4 × 6 cm²) pouch Zn‐based devices, showing remarkable flexibility and practicality.