Solution Structure and Magnesium Deposition Electrochemistry of Mixing Alkylmagnesium Halide with Magnesium Sulfonyl Amide/Glyme Solution

To elucidate effective species and their quantitative requirements for reversible magnesium deposition, a triglyme solution of ethylmagnesium bromide (EtMgBr) complex was mixed with magnesium bis(trifluoromethanesulfonyl) amide/triglyme solution in various ratios. The mixed electrolyte characteristics have been assessed using electrochemical magnesium deposition tests, titration of methanol, and Raman spectroscopy. The existence of EtMgBr reduces the overpotential of magnesium deposition. The Coulombic efficiency of this process varies linearly with the EtMgBr content, although the active EtMgBr decreases more than expected from the mixing ratio. Raman spectra for the mixed electrolyte suggest a change in the structure of magnesium bromide species and coordination mode of magnesium by mixing of EtMgBr with magnesium sulfonylamide salt. (C) The Electrochemical Society of Japan, All rights reserved.