N.A. Thieu, P. Gao, W. Li, S. Zhang, S. Chen, X. Li, X. Liu
West Virginia University,
United States
Keywords: La3+ cations, sodium dodecyl sulfate, hybrid additives, adsorption layer, (002) plane, dendrite−free, Zn anode
Summary:
The anode−electrolyte interface in aqueous zinc−ion batteries (AZIBs) is susceptible to instability due to irreversible processes, including dendrite growth, parasitic water−induced side reactions, and hydrogen evolution reactions (HER). Herein, this study proposes a novel electrolyte system utilizing La3+ cations and an anionic surfactant, sodium dodecyl sulfate (SDS), as a hybrid additive in a conventional 1 M ZnSO4 electrolyte to regulate the Zn anode−electrolyte interface. Experimental investigations and theoretical calculations demonstrate that the interaction between La3+ and SDS leads to the formation of a robust interfacial adsorption layer on the Zn surface to promote preferential deposition of Zn with the (002) plane, thereby resulting in a dendrite−free Zn anode. Meanwhile, dodecyl sulfonate (DS−) anions can hinder the adsorption of free water molecules and alter the electrode−electrolyte interface, thereby modulating Zn2+ deposition and inhibiting undesired side reactions. As a result, Zn||Zn symmetric cells substantially prolong cycle life for over 1430 h and 720 h at 1 mA cm−2 and 5 mA cm−2, respectively, while the Zn||Cu asymmetric cell exhibits high reversibility with an impressive Coulombic efficiency of 99.3% at 1 mA cm−2. This study presents an innovative perspective on electrolyte engineering strategies, leveraging synergistic cationic and surfactant interactions to achieve highly reversible Zn metal anodes in aqueous electrolytes.