γ-Aminobutyric acid additive enables high stability and long-life zinc anodes via regulating Zn2+ solvation structure and constructing interfacial hydrophobic layer

• GABA electrolyte additive promotes stable interface and uniform Zn deposition. • GABA electrolyte additive changes the solvation structure of Zn 2+ . • The Zn||Zn battery can stably cycle over 4500 h at 0.5 mA cm -2 and 0.5 mAh cm -2 . • The Zn||Cu battery can stably cycle over 700 cycles with average CE of 99.64 %. While aqueous zinc-ion batteries (ZIBs) show great promise for grid-scale energy storage, their practical implementation is hindered by persistent challenges including uncontrolled dendrite formation and parasitic hydrogen evolution reactions. To address these limitations, this work proposed a molecular engineering strategy utilizing γ-aminobutyric acid (GABA) as a multi-functional electrolyte additive. The amphoteric nature of GABA, featuring both carboxyl and amino moieties, enables dual modulation of zinc-ion solvation chemistry: (1) Reconstruction of the primary Zn 2+ solvation structure through competitive coordination, effectively replacing water molecules in the hydration shell; (2) Disruption of bulk electrolyte hydrogen-bond networks, significantly suppressing water activity. Notably, GABA demonstrates spontaneous adsorption on zinc surfaces, forming an interfacial hydrophobic layer through the alignment of its alkyl chains, physically isolating reactive water molecules. The combined effects yield exceptional electrochemical performance, as evidenced by Zn||Zn symmetric cell tests demonstrating stable cycling over 220 h at 10 mA cm -2 and 10 mAh cm -2 and ultralong durability exceeding 4500 h at 0.5 mA cm -2 and 0.5 mAh cm -2 . This work provides fundamental insights into electrolyte design principles for next-generation metal anode batteries through precise solvation structure manipulation and interface engineering. This image shows the stable voltage profile of a zinc anode with a GABA-derived SEI layer. The modification effectively alters the Zn 2+ solvation structure and interface, achieving exceptional long-term cycling stability over 4500 h, which is crucial for advanced zinc-based batteries.