Tailored Polymer‐Inorganic Bilayer SEI with Proton Holder Feature for Aqueous Zn Metal Batteries

Abstract Conventional solid‐electrolyte interface (SEI) in aqueous Zn‐ion batteries mainly acts as a physical barrier to prevent hydrogen evolution reaction (HER), while such SEI is prone to structural deterioration stemming from uneven Zn deposition at high current densities. Herein, we propose an in situ structural design of polymer‐inorganic bilayer SEI with a proton holder feature by aniline‐modulated electrolytes. The Zn(OTF) 2 exhibits a lower LUMO energy level in comparison to aniline, resulting in the formation of a bilayer structure characterized by an inner ZnF 2 layer and an outer polyaniline (PANI) layer. The ZnF 2 with high stiffness and strength effectively suppresses Zn dendrites. Meanwhile, the…