Stabilizing Zinc Anodes Through Trace Additive Mediated Solvation and Hydrogen-Bond Network

Aqueous zinc-ion batteries (AZIBs) are attractive for large-scale energy storage but suffer from severe hydrogen evolution reaction (HER) and uncontrolled dendritic zinc growth, both rooted in the interfacial water structure. Here, a trace amount of DL-2,3-dimercapto-1-propanesulfonic acid sodium salt (DMPS) is introduced as an electrolyte additive. Owing to its Zn affinitive dual thiol (-SH) groups and the highly negatively charged, hydrophilic sulfonate (-SO₃ ^-) moieties, DMPS anion (DMPS^-) preferentially adsorbs on the Zn surface, enabling simultaneous coordination with Zn^{2 +} and interaction with H₂O molecules. As a result, DMPS^- enters the Zn²⁺ solvation sheath and simultaneously disrupts the interfacial hydrogen-bond network, lowering water activity and impeding proton transfer. Consequently, HER is effectively suppressed. Moreover, through selective adsorption onto specific zinc crystal planes, DMPS^- promotes uniform zinc deposition with a preferred (101) orientation. As a result, Zn||Zn symmetric cells exhibit ultralong cycling stability exceeding 2000 h, and Zn||MnO₂ full cells deliver enhanced rate capability and prolonged cycling life. This work demonstrates that rational modulation of interfacial water via trace electrolyte additives is an effective strategy for stabilizing Zn metal anodes.