Tailoring Oxygen‐Depleted and Unitary Ti3C2Tx Surface Terminals by Molten Salt Electrochemical Etching Enables Dendrite‐Free Stable Zn Metal Anode

Abstract

AbstractTwo‐dimensional Ti3C2Tx MXene materials, with metal‐like conductivities and versatile terminals, have been considered to be promising surface modification materials for Zn‐metal‐based aqueous batteries (ZABs). However, the oxygen‐rich and hybridized terminations caused by conventional methods limit their advantages in inhibiting zinc dendrite growth and reducing corrosion‐related side reactions. Herein, −O‐depleted, −Cl‐terminated Ti3C2Tx was precisely fabricated by the molten salt electrochemical etching of Ti3AlC2, and controlled in situ terminal replacement from −Cl to unitary −S or −Se was achieved. The as‐prepared −O‐depleted and unitary‐terminal Ti3C2Tx as Zn anode coatings provided excellent hydrophobicity and enriched zinc‐ionophilic sites, facilitating Zn2+ horizontal transport for homogeneous deposition and effectively suppressing water‐induced side reactions. The as‐assembled Ti3C2Sx@Zn symmetric cell achieved a cycle life of up to 4200 h at a current density and areal capacity of 2 mA cm−2 and 1 mAh cm−2, respectively, with an impressive cumulative capacity of up to 7.25 Ah cm−2 at 5 mA cm−2//2 mAh cm−2. These findings provide an effective electrochemical strategy for tailoring −O‐depleted and unitary Ti3C2Tx surface terminals and advancing the understanding of the role of specific Ti3C2Tx surface chemistry in regulating the plating/stripping behaviors of metal ions.