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

ABSTRACT 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 MnO 2 ||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.