Synergistic Regulation of Hydrogen Bonds and Electrocrystallization for Enhanced Aqueous Zinc Batteries

Aqueous zinc ion batteries are promising candidates for large scale energy‐storage due to their combination of inherent security and abundant reserves. The Zn metal undergoes continuous plating and stripping during electrochemical cycling, accompanied by parasitic side reactions and dendrite growth, which severely impedes the commercialization of batteries. Here, an innovative strategy is introduced in electrolyte engineering, dedicated to enhancing the stability at the Zn/electrolyte interface. Theoretical calculations and in situ experimental analyses collectively demonstrate that methyl sulfonyl methane (MSM) additives are beneficial in jointly modulating the hydrogen bonding network and the Zn2+ solvation structure, which in turn restricts H2O activity at the interface. Concurrently, the preferential adsorption of MSM on the Zn surface facilitates the controlled growth of compact zinc layers while suppressing dendritic and parasitic reactions. By modulating the electrolyte and managing the electrode interface, the Zn||Zn symmetric battery can be reversibly cycled over 150 days at a current density of 2 mA cm−2, and the assembled Zn||Cu half‐batteries show impressive cycling stability over 3100 cycles. This study provides an in‐depth comprehension of the Zn2+ plating/stripping behavior, and the development of sophisticated electrolyte systems offers practical guidance for constructing high‐performance zinc‐based batteries. Methyl sulfonyl methane (MSM), a multifunctional additive utilized in aqueous zinc‐ion batteries, effectively modulates the solvation structure around zinc ions and the electrode/electrolyte interface. It facilitates a homogeneous zinc plating process, thereby conferring the batteries an exceptionally long cycle life.