A novel magnesium electrolyte containing a magnesium bis(diisopropyl)amide–magnesium chloride complex for rechargeable magnesium batteries

Abstract

We developed a unique class of non-Grignard, weakly nucleophilic magnesium electrolytes based on a simple mixture of magnesium compounds: magnesium bis(diisopropyl)amide (MBA) and magnesium chloride (MgCl₂). A new active species [(C₃H₇)₂N]MgCl₂–MgCl confirmed by NMR spectroscopy and DFT theoretical calculations affords low over-potentials for overall Mg deposition–dissolution without extra conditioning or activation and high and stable cycling coulombic efficiencies. The reduced corrosive nature toward non-noble metals (up to 2.10 V on stainless steel and copper) can be achieved after the addition of AlCl₃. The MBA–2MgCl₂/THF electrolyte exhibits good compatibility with the Mo₆S₈ cathode and the MBA–2MgCl₂ + AlCl₃/THF electrolyte is more applicable for high energy density Mg–S batteries. Overall, this study demonstrates a novel strategic approach to develop highly efficient new electrolyte systems for rechargeable magnesium batteries.