Kinetic Control on Hydrogen Generation of Ammonia and Lithium Hydride System

摘要

Ammonia (NH_3) and lithium hydride (LiH) is one of the promising hydrogen storage systems because of its high gravimetric and volumetric hydrogen density. Furthermore, the hydrogen generating reaction proceeds even at room temperature. However, the low reaction yield and reaction rate are problems for development as practical application. Pristine LiH shows low yields of less than 10% even after the reaction with NH_3 for 24 h. We found that activation for LiH by ball milling drastically improved both of yield and rate of the reaction. As a result, more than 80% of the yield of the reaction with NH_3 can be obtained in the case of activated LiH. In order to clarify the mechanism of the reaction, the relation to microstructure, surface properties, and reactivity of LiH are discussed.