This study introduces phenylalanine (Phe) as a multifunctional additive in aqueous zinc-ion batteries (AZIBs) to enhance the reversibility and stability of the zinc anode. Phe, an amphipathic amino acid, forms a nucleophilic-hydrophobic interface that homogenizes Zn²⁺ flux while repelling water molecules from contacting the Zn anode. The preferential reduction of Phe prior to water facilitates the in situ formation of an organic-inorganic hybrid solid electrolyte interphase (SEI), enhancing interfacial stability. The hydrophobic benzene ring of Phe repels water molecules, while the hydrophilic hydroxyl and carboxyl groups attract Zn²⁺ ions, promoting uniform Zn deposition. The triple protection of Phe, including solvation structure regulation, amphipathic molecular adsorption, and SEI formation, significantly improves the electrochemical performance of Zn||Zn and Zn||LMO cells, even at extreme diluted electrolytes. The Zn||Zn cells exhibit an ultralong cycle life of 5250 h, and the Zn||LMO full cells retain 77.3% capacity after 300 cycles. The Phe additive also enhances the rate performance of Zn||Zn cells and enables practical applications in AZIBs, as demonstrated by the successful operation of a model airplane powered by a Zn||LMO cell. The study confirms the feasibility of Phe as a promising electrolyte additive for improving the commercialization of AZIBs.This study introduces phenylalanine (Phe) as a multifunctional additive in aqueous zinc-ion batteries (AZIBs) to enhance the reversibility and stability of the zinc anode. Phe, an amphipathic amino acid, forms a nucleophilic-hydrophobic interface that homogenizes Zn²⁺ flux while repelling water molecules from contacting the Zn anode. The preferential reduction of Phe prior to water facilitates the in situ formation of an organic-inorganic hybrid solid electrolyte interphase (SEI), enhancing interfacial stability. The hydrophobic benzene ring of Phe repels water molecules, while the hydrophilic hydroxyl and carboxyl groups attract Zn²⁺ ions, promoting uniform Zn deposition. The triple protection of Phe, including solvation structure regulation, amphipathic molecular adsorption, and SEI formation, significantly improves the electrochemical performance of Zn||Zn and Zn||LMO cells, even at extreme diluted electrolytes. The Zn||Zn cells exhibit an ultralong cycle life of 5250 h, and the Zn||LMO full cells retain 77.3% capacity after 300 cycles. The Phe additive also enhances the rate performance of Zn||Zn cells and enables practical applications in AZIBs, as demonstrated by the successful operation of a model airplane powered by a Zn||LMO cell. The study confirms the feasibility of Phe as a promising electrolyte additive for improving the commercialization of AZIBs.