Development of Magnesium-Based Material with Hydrogen-Storage Capacity of 7 wt.

ABSTRACT

TiCl3 was chosen as an additive to increase hydriding and dehydriding rates of Mg. In our previous works, we found that the optimum percentage of additives that improved the hydriding and dehydriding features of Mg was approximately ten. Specimens consisting of 90 wt% Mg and 10 wt% TiCl3 (named Mg-10TiCl3) were prepared by high-energy ball milling in hydrogen. The specimens' hydriding and dehydriding properties were then studied. Mg-10TiCl3 had an effective hydrogenstorage capacity (the quantity of hydrogen absorbed in 60 min) of approximately 7.2 wt% at 593 K under 12 bar H2 at the second cycle. After high-energy ball milling in hydrogen, Mg-10TiCl3 contained Mg, ß-MgH2, and small amounts of γ-MgH2 and TiH1.924. TiH1.924 remained undercomposed even after dehydriding at 623 K in a vacuum for 2 h. The hydriding and dehydriding properties of Mg-10TiCl3 were compared with those of other specimens such as Mg-10Fe2O3, Mg-10NbF5, and Mg-5Fe2O3-5Ni, for which the hydrogen-storage properties were previously reported.