Synthesis and dehydrogenation of LiCa(NH2)3(BH3)2

We report the synthesis of a new hydrogen storage material with a composition of LiCa(NH2)3(BH3)2. The theoretical hydrogen capacity of LiCa(NH2)3(BH3)2 is 9.85 wt.%. It can be prepared by ball milling the mixture of calcium amidoborane (Ca(NH2BH3)2) and lithium amide (LiNH2) in a molar ratio of 1:1. The experimental results show that this material starts to release hydrogen at a temperature as low as ca. 50 °C, which is ca. 70 °C lower than that of pure Ca(NH2BH3)2 possibly resulting from the active interaction of NH2− in LiNH2 with BH3 in Ca(NH2BH3)2. ca. 4.1 equiv. or 6.8 wt.% hydrogen can be released at 300 °C. The dehydrogenation is a mildly exothermic process forming stable nitride products.

► A new phase, LiCa(NH2)3(BH3)2, is synthesized. ► The dehydrogenation of LiCa(NH2)3(BH3)2 is reported. ► NH2− in lithium amide interacts with BH3 in calcium amidoborane strongly, resulting in a lower temperature for dehydrogenation.