A Bifunctional Descriptor Inspired by Electron‐Donating Ability for Regulating Dendrite Growth and Parasitic Reactions in Zinc‐Ion Batteries

Aqueous zinc-ion batteries (AZIBs) are promising alternatives to lithium-based systems but are limited by dendritic growth and parasitic reactions at the Zn anode. Here, we introduce a bifunctional physicochemical descriptor (Φ) that evaluates hydrogen-bond network strength in the electrolyte and interfacial adsorption strength at the electrolyte/electrode interface, capturing the respective tendencies of parasitic reaction and dendritic formation. This descriptor enables mechanism-informed screening of amino acid additives and identifies l-tyrosine as an effective regulator. Multiscale characterizations show that trace l-tyrosine (1 mM) suppresses hydrogen evolution by restructuring the hydrogen-bond network and promotes Zn(002)-oriented deposition via interfacial adsorption. As a result, Zn||Zn symmetric cells exhibit prolonged stability, exceeding 4500 h at 1 mA cm⁻² and over 12 000 cycles at 10 mA cm⁻², while MnO₂||Zn full cells retain 95.66% capacity after 500 cycles at 1 A g⁻¹. This work establishes a descriptor-based framework for regulating dendrite growth and parasitic reactions and provides a rational strategy for electrolyte additive design in aqueous metal batteries.