Formation reaction of Mg2FeH6: effect of hydrogen absorption/desorption kinetics

In this paper we address some aspects of the kinetics of hydrogen absorption and desorption of Mg2FeH6 nanocomposite powder. The Mg2FeH6 material was prepared from a 2Mg-Fe composition by reactive milling under H2 pressure at room temperature. After mechano-chemical processing, the material was mainly constituted of Mg2FeH6 having a hydrogen gravimetric capacity corresponding to 94% of the theoretical capacity. The kinetics of hydrogen absorption at constant temperature and the transformation of phases during this process were studied. The kinetics of hydrogen absorption presented a two-step b...