Hybrid twin-metal aluminum–magnesium electrolytes for rechargeable batteries

The depletion of lithium and cobalt resources is pushing researchers to develop a more sustainable energy economy in the battery field. The growth of the electric vehicles market is increasing the demand of high energy density storage devices beyond lithium-ion technology. In this work the synthesis and characterization of innovative ionic liquid-based electrolytes for aluminum and magnesium conduction is described. The presence of the two elements shows a synergistic effect, which raises the electrochemical performance to levels that have never been reached by a single metal electrolyte. The interplay between composition, structure and interactions of the ionic species composing the electrolyte is studied. The twin electrolytes are able to deposit and strip simultaneously Mg and Al with a low overvoltage (50 mV), a Coulombic efficiency of 99.66% and lasting for more than 700 cycles. Finally, a prototype battery is assembled and tested under operating conditions.