Trace‐Level Green Bio‐Derived Amino Acid Molecular Leveling Agent Enables Dendrite‐Free and Long‐Lifespan Zinc Metal Anodes

Abstract The poor reversibility of Zn metal anodes, caused by dendrite growth and water‐induced side reactions, hinders the commercialization of aqueous zinc‐ion batteries (AZIBs). To address these issues, regulating Zn 2+ solvation structure, controlling nucleation behavior, and constructing a robust solid electrolyte interphase (SEI) are crucial. Herein, a trace‐level (10 mg mL −1 ) bio‐derived surface‐leveling agent, N,N‐dihydroxyethyl glycine (BICINE), is introduced to tailor the interfacial environment. With multiple coordinating groups, BICINE adsorbs onto the Zn surface, homogenizes nucleation, reconstructs solvation sheath, and induces a hybrid SEI. Meanwhile, it promotes the formation of a uniform cathode electrolyte interphase (CEI), stabilizing cathode morphology and preventing irreversible degradation. These synergistic effects suppress dendrite growth and parasitic reactions, enabling highly reversible Zn plating/stripping. Consequently, symmetric Zn||Zn cells demonstrate remarkable stability, with the capability to operate for over 5,300 h at 5 mA cm −2 /1 mA h cm −2 and maintain stable performance at a high depth of discharge (88.2%). Asymmetric Cu||Zn cells exhibit exceptional Coulombic efficiency of 99.9% over 1,650 cycles. Even with a low N/P ratio of 3, Zn||NH 4 V 4 O 10 full cells retain 89.7% of their capacity after 250 cycles at 2 A g −1 . The low‐cost BICINE strategy holds great promise for advancing the commercialization of AZIBs.