In Situ Formed Robust Solid Electrolyte Interphase with Organic–Inorganic Hybrid Layer for Stable Zn Metal Anode

Stabilizing the Zn anode/electrolyte interface is critical for advancing aqueous zinc ion storage technologies. Addressing this challenge helps minimize parasitic reactions and controls the formation of Zn dendrites, which is fundamental to achieving highly reversible Zn electrochemistry. In this study, 2% by volume of dimethyl sulfoxide (DMSO) is introduced into the baseline zinc sulfate (ZS) electrolyte, which acts as an efficient regulator to form a robust solid-electrolyte interphase (SEI) on the Zn anode. This innovative approach enables uniform Zn deposition and does not substantially modify the Zn²⁺ solvation structure. The Zn||Zn symmetric cell exhibits an extended cycle life of nearly one calendar year (>8500 h) at a current density of 0.5 mA cm^-2 and an areal capacity of 0.5 mAh cm^-2. Impressive full cell performance can be achieved. Specifically, the Zn||VS₂ full cell achieves an areal capacity of 1.7 mAh cm^-2, with a superior negative-to-positive capacity ratio of 2.5, and an electrolyte-to-capacity ratio of 101.4 µL mAh^-1, displaying remarkable stability over 1000 cycles under a high mass loading of 11.0 mg cm^-2 without significant degradation. This innovative approach in electrolyte engineering provides a new perspective on in situ SEI design and furthers the understanding of Zn anode stabilization.