Specific adsorption effect induces differential deposition structures to achieve 2-year stable cycling of zinc metal anodes

Abstract

The High reactivity of zinc metal anodes (ZMA) in aqueous solutions leads to dendrite growth and side reactions, greatly hindering their commercialization. Introducing a trace amount of 1-butyl-3-methylimidazolium iodide into the electrolyte forms a dual-ion specific adsorption layer. This adsorption layer creates a H₂O-poor Helmholtz layer, effectively preventing side reactions between active water dipoles and ZMA, and accelerating the flux and diffusion of Zn²⁺ at the anode-electrolyte interface, reducing electrochemical polarization. Additionally, I^- plays a decisive role in the nucleation and growth of Zn, selectively controlling the direction of zinc deposition according to the differences in the cycling system. The adjustable deposition direction avoids lattice distortion caused by Zn(002) or dendrite growth caused by Zn(101). Therefore, Zn//Cu and Zn//Zn batteries have a record Coulombic efficiency (99.95 %) and cycle life (19,000 h, over 2 years). Characterization techniques such as synchrotron radiation, multiphysics field simulations and density functional theory calculations are used to validate the stability enhancement mechanism. This work provides a reference for achieving efficient and stable ZMA. Additionally, the simple method for separating and recycling high-value BMIMI from waste electrolytes is of significant importance for green and sustainable chemistry.