Side Reaction Pathway Modulation for Hydrogen Evolution‐Free Aqueous Zn‐Ion Batteries

Abstract Aqueous Zn‐ion batteries offer excellent safety and cost benefits, but their application is limited by side reactions such as hydrogen evolution and dendritic Zn growth. In this study, telluric acid is introduced as an electrolyte additive to induce the in situ formation of a ZnO–TeO 2 –Te ternary composite layer on the Zn anode. Unlike sulfuric or selenic acid, telluric acid promotes the formation of a dense, rice grain‐like layer with facet‐controlled ZnO (002) orientation and TeO 2 /Te composite. This engineered interphase effectively suppresses Zn corrosion, byproduct formation, and dendrite growth, as confirmed by surface analyses and operando imaging. As a result, telluric acid additive enables stable cycling over 1500 h at 1 mA cm −2 and operate for 250 h even at 50% depth‐of‐discharge condition. Zn/NaV 3 O 8 full cells also show improved capacity retention, enhanced reversibility, and interfacial stability. This work highlights a promising electrolyte engineering strategy for high‐performance aqueous Zn‐ion batteries.