Stabling Zinc Metal Anode with Polydopamine Regulation through Dual Effects of Fast Desolvation and Ion Confinement

Abstract

AbstractMetal zinc is recognized as a promising anode candidate for aqueous zinc‐ion batteries (AZIBs), however, dendrites and byproducts formation severe deteriorate its reversibility and practical lifespan. Herein, a polydopamine (PDA) layer, which offers the dual effects of fast desolvation and ion confinement, is constructed on the surface of a Zn anode for efficient AZIBs. The abundant polar functional groups in PDA significantly enhance interfacial contact in aqueous media, which reduces the number of water molecules reaching the zinc surface through fast desolvation, thus lowering the energy barrier for Zn2+ migration. Furthermore, the porous PDA coating controls the ion flux via the ion‐confinement effect, thereby accelerating Zn2+ kinetics on the zinc surface. Consequently, Zn@PDA exhibits significantly improved Zn2+ deposition kinetics (nucleation potential of only 32.6 mV vs 50.2 mV of bare Zn) compared with bare Zn at 2.0 mA cm−2, with a dendrite‐free surface and negligible byproduct formation. When paired with a MnO2 cathode, the Zn@PDA//MnO2 cell delivers high discharge capacity and long cycle stability without significant performance deterioration over 1000 cycles at 1.0 A g−1. Additionally, the cell demonstrates excellent shelving‐restoring performance.