A New Family of Novel Electrolytes for Rechargeable Magnesium Batteries

Recently, rechargeable magnesium batteries have been attracting an increased attention owing to a high volumetric capacity (3833 mAh cm^-3 vs. 2046 mAh cm^-3  for Li) , absence of dendrites formation and lower costs of Mg metal. Nonetheless, rechargeable Mg battery technologies suffer from critical challenges caused by the absence of practical high voltage cathodes and appropriate electrolytes.  The electrolytes used are currently Grignard and/or organohalo magnesium reagents based as conventional inorganic and ionic Mg salts passivate the Mg metal surface^[1]. These organohalo salts were found to cause severe corrosion of the metallic battery components such as current collectors.  The corrosive nature has been linked to the presence of the chloride ion which is an integral part in these electrolytes’ make. We have been pioneering the development of new class of Mg electrolytes that are not corrosive based on borohydrides and their derivative salts.  Recently, we demonstrated several electrolytes with high compatibility with the magnesium metal representing the first and only examples of inorganic, relatively ionic and halide free salts reported to date that are compatible with Mg metal^[2] as seen in Figure one. In addition, we have just proposed a new design strategy to create magnesium battery electrolytes with high oxidative stability based on borohydrides derivatives ^[3]. These novel electrolytes were demonstrated in rechargeable magnesium batteries.  In this presentation, we will explain our design strategies, discuss fundamental properties obtained from systematic studies and share up-to-date results related to these new promising systems.