Magnesium solid electrolytes based on coordination complexes of magnesium borohydride

We present unprecedented high Mg conductivity in chelated Mg complexes of magnesium borohydride, Mg(BH4)2. The highest conductivity of 5∗10 Scm at 30 °C and 6∗10 Scm at 70 °C was found in the borohydride-ethylenediamine complex Mg(en)1(BH4)2 as shown in figure 1. The coordination complexes are stable against elemental magnesium, support cycling in a potential window of 1.2 V, and allow reversible magnesium plating/stripping [1]. Our results demonstrate that partially chelated Mg complexes represent a promising platform for the development of an all-solid-state magnesium battery.