Effects of mechanical activation on dehydrogenation of the lithium amide and lithium hydride system

The dependence of the dehydriding reaction of the LiNH2 and LiH mixture on the degree of mechanical activation was investigated. Different degrees of mechanical activation were obtained via different conditions of high-energy ball milling. The enhanced reaction kinetics was related to changes in the characteristics of the powder mixtures induced by high-energy ball milling. The more mechanical activation, the more reduction in the onset, peak, and completion temperatures for the dehydriding reaction. Mechanical activation could lead to a decrease in the activation energy of the dehydriding reaction. A 60% reduction in the activation energy was achieved by high-energy ball milling at room temperature for 24 h. High-energy ball milling also effectively prevented escaping of NH3 from the LiNH2 and LiH system. A proposal on dual roles of LiH was put forward to explain the mechanism of the dehydriding reaction and all of the phenomena observed in this study.