Evaluation of Mg[N(SO₂CF₃)₂]₂/Acetonitrile Electrolyte for Use in Mg-Ion Cells

Abstract

Mg[N(SO2CF3)2]2/Acetonitrile electrolyte was evaluated for use in Mg-ion cells. It was found to have a stable potential range between about −0.2 V and 2.8 V vs. Mg against a stainless steel working electrode. Higher voltages resulted in stainless steel corrosion, while lower voltages resulted in acetonitrile reduction. No Mg plating was observed. Reversible intercalation of Mg into Mo6S8 was demonstrated in this electrolyte with significantly lower irreversible capacity, compared to cycling in Grignard-based electrolytes. Mg[N(SO2CF3)2]2/Acetonitrile electrolyte may be useful for Mg-ion batteries, if the negative electrode has sufficiently high voltage to avoid acetonitrile reduction.