Polyoxometalate Initiated In situ Conformal Coating of Multifunctional Hybrid Artificial Layers for High Performance Zinc Metal Anodes

Abstract Aqueous zinc (Zn) metal batteries are very attractive owing to the high theoretical capacity (820 mAh g⁻¹), meritable electrode potential (−0.76 V vs SHE), low cost, and environmental friendliness of Zn metal anodes. However, the dendrite formation, corrosion, and water decomposition on Zn metal anodes should be resolved for their practical applications. Herein, conformally coated multifunctional organic/inorganic hybrid artificial layers are demonstrated for the reversible and stable Zn deposition. These hybrid layers are synthesized through polyoxometalate (POM) initiated polymerization into poly(1,3‐dioxolane) (Poly(DOL)) and directly coated onto the Zn surface. Moreover, POM acted as chemical bridge connecting Poly(DOL) with Zn metal anode to construct mechanically robust layers with a thickness of ≈40 nm. The fast and selective Zn²⁺ ion transport of multifunctional POM/Poly(DOL) hybrid layer (POMDOL) and their preferential growth into (002) crystalline plane are attributed to the reversible Zn deposition. Accordingly, POMDOL coated Zn (PDOLZn) anodes achieves an extended cycling period up to 2,876 hours with a cumulative capacity of 29 Ah g⁻¹ at 20 mA cm⁻² and 1 mAh cm⁻². Moreover, depth of discharge (DOD) of 40% is achieved. Consequently, the PDOLZn || β‐MnO₂ full cells delivered the high specific capacity of 245 mAh g⁻¹ and long‐term stability over 1 000 cycles.