Hydriding and Dehydriding Properties of Zinc Borohydride, Nickel, and Titanium-Added Magnesium Hydride

Abstract

A Zn(BH4)2 sample was prepared by milling ZnCl2 and NaBH4 in a planetary ball mill under Ar gas. This sample contained NaCl. Then, 90 wt% MgH2-5 wt% Zn(BH4)2-2.5 wt% Ni-2.5 wt% Ti samples [named 90MgH2-5Zn(BH4)2-2.5Ni-2.5Ti] were prepared by milling in a planetary ball mill under H2 gas. The hydrogen absorption and release properties of the prepared samples were investigated. In particular, the variations of the initial hydriding and dehydriding rates with temperature were examined. SEM micrographs and XRD patterns of 90MgH2-5Zn(BH4)2-2.5Ni-2.5Ti after reactive mechanical grinding and after hydriding-dehydriding were also studied. Particle size distributions and BET specific surface areas of 90MgH2-5Zn(BH4)2-2.5Ni-2.5Ti after reactive mechanical grinding and after 11 hydriding-dehydriding cycles were analyzed. The 90MgH2-5Zn(BH4)2-2.5Ni-2.5Ti had an effective hydrogen storage capacity (the quantity of hydrogen absorbed for 60 min) of near 5 wt% (4.91 wt% at 593 K).