Water‐Repellent Ionic Liquid Skinny Gels Customized for Aqueous Zn‐Ion Battery Anodes

Abstract Despite the enormous potential of aqueous zinc (Zn)‐ion batteries as a cost‐competitive and safer power source, their practical applications have been plagued by the chemical/electrochemical instability of Zn anodes with aqueous electrolytes. Here, ionic liquid (IL) skinny gels are reported as a new class of water‐repellent ion‐conducting protective layers customized for Zn anodes. The IL skinny gel (thickness ≈500 nm), consisting of hydrophobic IL solvent, Zn salts, and thiol‐ene polymer compliant skeleton, prevents the access of water molecules to Zn anodes while allowing Zn 2+ conduction for redox reactions. The IL‐gel‐skinned Zn anode enables sustainable Zn plating/stripping cyclability under 90% depth of discharge (DOD Zn ) without suffering from water‐triggered interfacial parasitic reactions. Driven by these advantageous effects, a Zn‐ion full cell (IL‐gel‐skinned Zn‐anode||aqueous‐electrolyte‐containing MnO 2 cathode) exhibits high charge/discharge cycling performance (capacity retention ≈95.7% after 600 cycles) that lies beyond those achievable with conventional aqueous Zn‐ion battery technologies.