Characterization of Hydrogen-Storage Properties and Physical Properties of Zinc Borohydride and Transition Metals-Added Magnesium Hydride

摘要

In this work, 90?wt.% MgH2 +?5?wt.% Ni?+?1.7?wt.% Zn(BH4)2 +?1.7?wt.% Ti?+?1.7?wt.% Fe samples (named 90MgH2 +?5Ni?+?1.7Zn(BH4)2 +?1.7Ti?+?1.7Fe) were prepared by milling in a planetary ball mill in a hydrogen atmosphere. The fraction of additives was small (10?wt.%) in order to increase hydriding and dehydriding rates without decreasing the hydrogen storage capacity much. The hydrogen absorption and release properties of the prepared samples were investigated. 90MgH2 +?5Ni?+?1.7Zn(BH4)2 +?1.7Ti?+?1.7Fe had an effective hydrogen storage capacity of 5?wt.%. The activation of 90MgH2 +?5Ni?+?1.7Zn(BH4)2 +?1.7Ti?+?1.7Fe was completed after 2 hydriding-dehydriding cycles. At n =?3, the sample absorbed 4.14?wt.% H for 5?min and 5.00?wt.% H for 60?min at 593?K under 12?bar H2. The sample dehydrided at the 3rd hydriding-dehydriding cycle contained Mg and small amounts of β-MgH2, MgO, Mg2Ni, TiH1.924, and Fe. The BET specific surface areas of the sample after milling in a hydrogen atmosphere and after 3 hydriding-dehydriding cycles were 57.9 and 53.2?m2/g, respectively.DOI: http://dx.doi.org/10.5755/j01.ms.23.1.14878