SYNTHESIS, STRUCTURAL CHARACTERIZATION AND HYDROGENATION BEHAVIOR OF THE NEW HYDROGEN STORAGE COMPOSITE ALLOY LA2MG17-XWT-PERCENT LANI5

Alloys with the general formula La2Mg17-x wt% LaNi5 (x = 10, 20, 30 and 40) have been synthesized and the hydrogen storage capacity of these new composite materials investigated. The materials were activated at temperatures of approximately 360-degrees-C under a hydrogen pressure of approximately 33 kg cm-2. Optimum storage capacity of 5.24% in terms of pressure and composition was observed for La2Mg17-10 wt% LaNi5 at approximately 400-degrees-C. This is one of the very highest hydrogen storage capacities known so far. The hydriding rate of La2Mg17 in the presence of LaNi5 is about 3-4 times that of La2Mg17 alone. In order to elucidate the role of LaNi5 in accelerating the hydrogen desorption rate of La2Mg17, the structural and microstructural characteristics of the composite material were carried out employing the XRD, SEM and EDAX techniques. The hydriding rate and hydrogen storage capacity are closely related to the microstructure and the types of phase present in the alloys.