Inherited construction of porous zinc hydroxide sulfate layer for stable dendrite-free Zn anode

Abstract

A stable Zn anode for mitigating dendritic growth, corrosion, and byproducts is vital for exhibiting high-performance electrochemical properties in aqueous Zn-ion batteries. An artificial solid/electrolyte interphase is an effective protective strategy for Zn anodes. Herein, a uniform layer of zinc hydroxide sulfate (ZHS) derived in situ from a ZIF-8 membrane was developed on a Zn anode. The ZHS layer inherited a well-ordered structure and porous channels from the ZIF-8 membrane and exhibited high ionic conductivity, low electronic conductivity, and strong interactions with Zn²⁺ ions, which facilitated the regulation of homogeneous Zn²⁺ flux and deposition for dendritic inhibition. The strong interactions between H₂O molecules and SO₄²⁻ ions in the ZHS layer could alter the solvation structure of hydrated Zn²⁺ ions to facilitate the desolvation process, thus mitigating H₂O-induced side reactions during Zn plating/stripping processes. The ZHS layer-coated Zn anode exhibited a remarkably long cycling lifespan of over 2800 h at a low current density of 1 mA cm⁻² (1 mA h cm⁻²) and over 1100 h at a high current density of 10 mA cm⁻² (5 mA h cm⁻²). This study provides a facile and feasible strategy to achieve the interfacial stability of Zn anodes for use in rechargeable aqueous Zn-ion batteries.