Stabilizing Zn anodes by constructing PEGMA protecting layers for high-performance Zn-ion batteries

As a promising candidate for grid-scale energy storage, rechargeable aqueous Zn-ion batteries (ZIBs) have many advantages including low cost, high safety, and environmental benignity. However, the Zn metal anode still suffers from severe dendrite and corrosion issues, hindering the practical application of ZIBs. Herein, we report a dense and uniform poly (ethylene glycol methyl ether methacrylate) (PEGMA) artificial protecting layer to alleviate these issues, by preventing the direct electrolyte/Zn anode contact while guiding the uniform migration of Zn²⁺ ions. Thanks to these merits, the cycling stability of Zn//Zn symmetrical cells is remarkably improved from 248 h up to 1096 h (at 1 mA cm⁻² and 1 mAh cm⁻²), and the Coulombic efficiencies (CEs) of the Zn striping/plating reaction is increased from 85.9% to 99.1%. Furthermore, the potential application of this strategy is further demonstrated in Zn//iodine (I₂) full batteries. Compared with the Bare-Zn//I₂ batteries, the PEGMA-Zn//I₂ full batteries deliver better CEs (99.5% vs. 99.3% in average at 0.2 A g⁻¹), cycling stability (capacity retention: 89.0% vs. 74.7% after 4000 cycles at 1 A g⁻¹) and shelf life (capacity retention: 78% vs. 71% after 50 h open-circuit storage), underscoring the application potential of this strategy in high-performance ZIBs.