Filings Morphology-Dependent Hydrogen Storage Properties of Magnesium-Rich Mg–Y–Zn Alloy

The filings of magnesium-rich Mg98.5Y1Zn0.5 alloy with different morphologies were prepared by using three kinds of files with arc (A), triangle (T), and flat (F) cross sections, respectively. Their microstructures, hydrogen storage properties, and mechanisms were investigated. The results reveal that these filings all present high storage capacity of about 7.0 wt% and excellent hydrogen sorption kinetics. However, the hydrogen ab/desorption properties of these filings exhibit obvious differences, which is closely related with their microscopic morphologies. Among them, the filings prepared by F file possess the best hydrogen sorption properties due to their higher saw teeth density and more dislocations induced through F file relative to those by A and T files. First-principles calculations reveal that the YH2 not only weakens the H–H and Mg–H bond strength, but also reduces the recombination energy of H atoms from MgH2 surface and the dissociation energy of H2 molecule on Mg surface during the hydrogenation/dehydrogenation of Mg–Y–Zn alloy.