Constructing interfacial molecular layer coupled with Zn2+ transfer/deposition kinetics modulation toward deeply reversible Zn anodes

Abstract

Irreversible Zn dendrite formation and hydrogen evolution reactions (HER) have significantly impeded the large-scale commercial deployment of aqueous zinc-metal batteries (AZMBs). Herein, we proposed an innovative interfacial strategy activated by the biomacromolecule Pullulan (Pul) on the surface of metal zinc anodes (ZMAs) within the electrolyte system. The combination of comprehensive experimental results and simulation calculations demonstrated that the spontaneous assembly of the interfacial molecular layer (IML), facilitated by the adaptive adsorption of Pul molecules, not only triggers the formation of a Zn²⁺-concentrated region and effectively balances ionic flux, but also simultaneously transforms the nucleation growth pattern of Zn²⁺ into an instantaneous and progressive hybridized mechanism, reconfiguring the Zn²⁺ transfer/deposition kinetics at the heterogeneous electrode/electrolyte interface. Moreover, the IML provides a stable shielding effect for hydrated hydrogen with high thermodynamic activity and SO₄²⁻ at the solid-liquid interface. Therefore, a smooth and compact Zn deposition layer devoid of dendritic growth is achieved during subsequent plating processes. As a result, Zn||Zn symmetric cells utilizing modified electrolytes exhibit remarkable plating/stripping performance exceeding 1800 hours without significant voltage fluctuations, which contributes to the exceptional long-term durability observed in Zn||CNTs@MnO₂ batteries.