Probing the effect of the stoichiometric ratio of Mg(CF3SO3)2/AlCl3 on optimizing the electrolyte performance

Low cost and safety qualify magnesium (Mg) metal batteries as one of the utmost post-lithium batteries. Nonetheless, most Mg electrolytes suffer from conditionality and incompatibility with most useable cathodes, hindering realising applicable Mg batteries. Herein, we study the effect of the stoichiometric ratio of Mg(CF3SO3)2/AlCl3 on the physical, electrical and electrochemical performance of an electrolyte system based on Mg(CF3SO3)2 in acetonitrile (ACN) and tetraethylene glycol dimethyl ether (G4). The physicochemical analyses include Fourier-transform infrared spectroscopy (FTIR), UV–Vis irradiation, electrochemical impedance spectroscopy (EIS) and Mg plating/stripping of electrolytes exhibit the optimum stoichiometric ratio is 0.28MAlCl3/0.17MMg(CF3SO3)2. The present study offers new approaches for designing promising efficient electrolytes for Mg batteries. The work extends to using an unconventional electrode based on sulphur, silicon carbide, and barium titanate to demonstrate the performance of the full cell. This optimised electrolyte coupled with the unconventional cathode allows a high initial specific discharge capacity, ~ 241 mAhg−1. However, the dissolution of polysulphides issue still exists and leads to irreversible cycling.