Room-Temperature Electrodeposition of Mg Metal from Amide Salts Dissolved in Glyme-Ionic Liquid Mixture

The electrodeposition of Mg metal from an ionic liquid–glyme mixture was investigated at room temperature. The mixture contains a glyme, a simple amide salt Mg(Tf2N)2 (Tf = SO2CF3), and a quaternary-ammonium Tf2N ionic liquid. Using the mixture bath, substantial cathodic electrodeposition of Mg at a large current density (∼10 mA cm−2) was observed, suggesting a change in coordination geometry around Mg2+ cation together with improved conductivity. By mixing diglyme, the conductivity increased by an order of magnitude (2.5 – 2.6 mS cm−1) compared to the glyme-free ionic liquid (0.35 mS cm−1) and the viscosity became as low as that of pure glyme. Additionally, potentiostatic electrolysis resulted in a non-dendritic thin film of elemental Mg with metallic luster.