Solvation Modification and Interfacial Chemistry Regulation Via Amphoteric Amino Acids for Long-Cycle Zinc Batteries

Abstract

To address the issues of dendrite growth and zinc corrosion in rechargeable zinc-air batteries, multifunctional glycine/valine additives are introduced into the electrolyte. By regulating the solvation shell structure and enhancing interfacial stability, these additives aim to protect the reversibility and stability of the zinc anode. Glycine/valine molecules inhibit the formation of the [Zn(H₂O)₆]²⁺ and Zn₅(OH)₈(OAc)₂·2H₂O by-products at the interface by replacing active water molecules in a strong alkaline environment. Additionally, they form a hydrophobic electric double layer on the zinc metal surface, during the charge/discharge process, and construct an in situ solid electrolyte interface layer. This further suppresses the hydrogen evolution reaction and dendrite growth. The superior long-term cycling stability of Zn||Zn cells, Zn||Cu, and zinc-air full cells demonstrates the effectiveness of glycine/valine additives.