Enhanced Chemical Stability of Zinc Metal Anodes with Deep Eutectic Electrolytes

To examine the impact of electrolytes on the chemical stability of zinc metal anodes, additional studies were performed to investigate the properties of deep eutectic electrolytes. The linear sweep voltammetry (LSV) curve indicated that the DES-3 electrolyte had an electrochemical window exceeding 3.5V at 25℃, with the hydrogen evolution reaction (HER) potential surpassing the electrochemical stability limit of water (Fig 4a). The use of DES-3 eutectic electrolyte as compared to the 3 M ZnCl2 electrolyte resulted in an increased corrosion potential of the zinc metal anode from 0.1V to 0.28V, along with a decreased corrosion current density (Fig S). The enhancement in corrosion potential and reduction in corrosion current density provided confirmatory evidence of the successful suppression of zinc surface corrosion. This can be attributed to the significant reduction in free water clusters and weakened hydrogen bonding between water molecules within the DES electrolyte system. Consequently, it reduces the activity of water molecules and imparts more stable physicochemical properties compared to aqueous electrolytes. This feature is expected to ensure the high stability of zinc metal anodes across a wide temperature range.