Phenoxyimine Ligand Molecular Structure Influence on Reversible Magnesium Electrode Reaction in a Magnesium Chloride Complex

Abstract

Non-aqueous electrolytes containing magnesium chloride complex in which magnesium is coordinated by synthesized phenoxyimine ligand have unique properties for magnesium deposition and dissolution. Those properties have been compared using ligands with different terminal groups. For electrochemical and Raman spectroscopic studies, mixed electrolytes were prepared by dissolving a phenoxyimine–magnesium-chloride complex and magnesium [bis(trifluoromethane sulfonyl)imide] in triglyme solvent. An electrolyte containing phenoxyimine with an n-butyl terminal group shows higher Coulombic efficiency of magnesium deposition than the electrolyte prepared with dimethylamine-terminated phenoxyimine, probably because of preferred formation of active triglyme–magnesium-chloride coordinated cations. By contrast, adding aluminum chloride to the electrolyte with n-butyl-terminated phenoxyimine adversely affected reversible magnesium deposition, probably because trapping of chloride occurred preferentially.

Keywords

• magnesium batteries
• magnesium chloride electrolyte
• phenoxyimine ligand