Ordered interface regulation at Zn electrodes induced by trace gum additives for high-performance aqueous batteries

Abstract

The reversibility and stability of Zn anodes in aqueous batteries are limited by dendritic growth and corrosion reactions. Herein, a macromolecule with abundant functional groups, i.e., 0.1 wt% locust bean gum (LBG), was used as an electrolyte additive and introduced in baseline 1 m ZnSO₄ to solve the above issues. Theoretical calculations and experimental analysis demonstrated that multiple aligned oxygen sites on LBG molecules allowed ordered interactions with the Zn surface. Meanwhile, the rest of the groups entered Zn²⁺ solvation shells and optimized the hydrogen bonding network at the interface. These active sites captured and homogenized the Zn²⁺ flux toward the electrode and modified the following desolvation paths. The resulting easier removal of solvated water and stronger hydrogen bonds inhibited side reactions, and the controlled removal of final LBG generated uniform deposits. As a result, stable Zn plating/stripping was achieved for 1600 h. Moreover, the mechanism could be extended to a series of macromolecular gum additives at concentrations below 0.1 wt%, presenting cost-effective aqueous electrolytes for Zn cells. Our work shows an ordered interface regulation strategy to promote the stability of Zn electrodes for high-performance aqueous batteries.