Molecular Engineering of a Weakly Coordinating Additive for Multiscale Stabilization of Zinc Metal Anodes

ABSTRACT

Aqueous zinc metal batteries are promising energy‑storage systems due to their high safety, low cost, and abundant zinc resources. However, their practical application is significantly constrained by persistent challenges at the zinc anode, including dendrite growth, hydrogen evolution, and corrosion in aqueous electrolytes. To overcome these limitations, we propose ethyl maltol (EM) as a weakly coordinating, small‑molecule additive that implements a synergistic strategy integrating solvation‑structure regulation, interfacial desolvation promotion, and defect‑site passivation. Theoretical and experimental results reveal that EM participates in the Zn ²⁺ solvation sheath and restructures the hydrogen‐bond network of water, thereby lowering water activity and retarding proton transport. Its weak coordination facilitates Zn ²⁺ desolvation at the interface, while its preferential adsorption on active Zn surface sites suppresses both hydrogen evolution and corrosion, enabling uniform and dendrite‑free Zn deposition. Benefiting from this synergistic regulation, Zn||Zn symmetric cells achieve stable cycling for over 3500 h at 1 mA cm ⁻² /1 mAh cm ^−2, and 771 h at 5 mA cm ⁻² /5 mAh cm ⁻² ; the Zn||V ₂ O ₅ full cell maintains a reversible capacity of 123.48 mAh g ⁻¹ after 5000 cycles at 5 A g ⁻¹ . This work offers a rational molecular‑design strategy for developing multifunctional electrolyte additives toward highly stable aqueous zinc metal batteries.