A Bifunctional Organosilane Additive for Dynamic pH Regulation and Interfacial Protection in Aqueous Zinc-Ion Batteries.

Aqueous zinc-ion batteries exhibit considerable potential for use in grid-scale energy storage. However, issues such as zinc dendrite growth and the occurrence of the hydrogen evolution reaction have limited their development. To address these challenges, this study develop Ormosil, a water-soluble organosilane additive for the electrolyte. In the electrolyte, Ormosil forms Si─O─Zn bonds with the zinc foil, thereby helping to protect the electrode from corrosion reactions. Moreover, on the electrode surface, it facilitates the formation of a solid-electrolyte-interphase layer, enabling rapid zinc-ion transport kinetics. Notably, the hydrophilicity of the organosilane is enhanced by the introduction of ─NH2 groups. Furthermore, the ─NH2 groups can bind to zinc ions and become part of their solvation shell; this incorporation helps suppress the hydrogen evolution reaction. Consequently, the single additive Ormosil provides both electrode protection and solvent restructuring. The cell using Ormosil additive exhibited excellent cycling stability (10 mA cm-2, 1000 h), a high average coulombic efficiency (CE = 99.74%), and a full cell with NVO cathode demonstrated high capacity retention (76.60%), superior to ZnSO4 (51.08%).