Close-packed growth and buffer action enabling stable and reversible Zn anode

Abstract

The chemical environment at the electrode/electrolyte interface is critical for the zinc ions deposition behavior and water-related parasitic side reactions. In this study, histidine, with imidazole group, is proposed as a multifunctional electrolyte additive to address the issues like dendrite formation, hydrogen evolution, and corrosion. The histidine exhibits a strong preferential adsorption on the Zn(100) and Zn(101) planes, leading to the exposure of Zn(002) facet, thereby promoting the close-packed growth along (002) plane and achieving a dendrite-free deposition. The imidazole group can both accept and release protons, which regulates the interfacial proton concentration, thus effectively suppressing hydrogen evolution reaction and the formation of undesirable by-products. The Zn||Zn symmetric cell with 0.1 M histidine exhibits good cycling stability, with over 3200 h of operation at 1 mA cm⁻², far surpassing cells without the additive (short circuit after 50 h). The Zn||Cu asymmetric cells demonstrate a high Coulombic efficiency of 99.8 % over 1400 cycles. The Zn||NH₄V₄O₁₀ pouch cell can be steadily operated with 80 % capacity retention after 200 cycles.