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

摘要

Metal zinc is recognized as a promising anode candidate for aqueous zinc-ionbatteries (AZIBs), however, dendrites and byproducts formation severe deteriorateits reversibility and practical lifespan. Herein, a polydopamine (PDA)layer, which offers the dual effects of fast desolvation and ion confinement, isconstructed on the surface of a Zn anode for efficient AZIBs. The abundantpolar functional groups in PDA significantly enhance interfacial contact inaqueous media, which reduces the number of water molecules reaching thezinc surface through fast desolvation, thus lowering the energy barrier for Zn~(2+)migration. Furthermore, the porous PDA coating controls the ion flux via theion-confinement effect, thereby accelerating Zn~(2+) kinetics on the zinc surface.Consequently, Zn@PDA exhibits significantly improved Zn~(2+) depositionkinetics (nucleation potential of only 32.6 mV vs 50.2 mV of bare Zn) comparedwith bare Zn at 2.0 mA cm~(?2), with a dendrite-free surface and negligiblebyproduct formation. When paired with a MnO_2 cathode, the Zn@PDA//MnO_2 cell delivers high discharge capacity and long cycle stability withoutsignificant performance deterioration over 1000 cycles at 1.0 A g~(?1). Additionally,the cell demonstrates excellent shelving-restoring performance.