Theoretical study on the hydrogen storage mechanism of the Li-Mg-N-H system

The gas-phase reaction mechanism of magnesium amide (Mg(NH2)2) and lithium hydride (LiH) to produce H2 is theoretically investigated using ab initio electronic structure and total energy calculations based on the density functional theory. The reaction with the addition of KH which has been reported to lower the activation energy is also considered. We identify intermediate complexes and transition states in the reaction pathways. Detailed processes are analyzed to show how each reactant (Mg(NH2)2 or LiH) contributes a H atom to produce a H2 molecule and KH induces a modified reaction mechanism with a lower reaction energy.