Effects of Metal Borohydrides on the Dehydrogenation Kinetics of the Li–Mg–N–H Hydrogen-Storage System

The combination of magnesium amide and lithium hydride represents a category of solid hydrogen-storage system with moderate hydrogen-storage conditions and good reversibility. At a molar ratio of 1:2 for the amide and hydride [Mg(NH 2 ) 2 -2LiH], the dehydrogenation kinetics of the system can be effectively accelerated by LiBH 4 . In this paper, the effects of kinetic enhancement were studied by doping the amide-hydride system at 1:2 molar ratio with NaBH 4 and Mg(BH 4 ) 2 along with LiBH 4 . Compared to the pristine system, the activation energies for the dehydrogenation were decreased by all three metal hydrides in the order of Mg(BH 4 ) 2 > LiBH 4 > NaBH 4 . The mechanism for the kinetic improvement of Mg(BH 4 ) 2 and NaBH 4 was investigated.