Inductive effect-driven Gibbs adsorption enabling stable zinc metal anodes

The development of aqueous zinc batteries (AZBs) is severely constrained by uncontrolled dendrite growth and parasitic interfacial reactions. Conventional solvation-dominated additives can mitigate these issues by altering the Zn2+ solvation structure, but they often compromise ion transport. Here, we introduce a molecular design principle for a non-solvating additive (NSA) based on inductive effects. Ethyl trifluoroacetate (ETFA), obtained by introducing an electron-withdrawing –CF3 group adjacent to the –C=O moiety of ethyl acetate (EA), participates minimally in the solvation structure but preferentially undergoes Gibbs adsorption at the Zn-electrolyte interface. This process reduces interfacial tension, reconstructs the electrical double layer, and orients ETFA molecules such that the hydrophilic –C=O groups face the electrolyte, modulating hydrogen-bonding networks, while the hydrophobic –CF3 groups anchor onto Zn to regulate deposition. As a result, dendrite formation and side reactions are simultaneously suppressed. With only 1 vol% ETFA, Zn-Cu cells achieve over 4000 stable cycles with 99.89% Coulombic efficiency. Zn-I2 full cells employing the modified electrolyte maintain stable operation for more than 500 cycles (6.8 mg cm−2, 10 μm Zn, N/P = 2.86), and 0.3 Ah Zn-I2 pouch cells (30 mg cm−2, 100 μm Zn) can cycle stably for over 200 cycles. These findings highlight the critical role of Gibbs adsorption in interfacial regulation and provide insights for the molecular design of high-performance additives for stable Zn anodes.