The Role of MgCl2 as a Lewis Base in ROMgCl-MgCl2 Electrolytes for Magnesium-Ion Batteries

A series of strong Lewis acid-free alkoxide/siloxide-based Mg electrolytes were deliberately developed with remarkable oxidative stability up to 3.5V (vs. Mg/Mg2+). Despite the perception of ROMgCl (R=alkyl, silyl) as a strong base, ROMgCl acts like Lewis acid, whereas the role of MgCl2 in was unambiguously demonstrated as a Lewis base through the identification of the key intermediate using single crystal X-ray crystallography. This Lewis-acid-free strategy should provide a prototype system for further investigation of Mg-ion batteries.