Hydrogen Storage Properties of Hydriding-Dehydriding Cycled Magnesium-Nickel-Iron Oxide Alloy

By measuring the absorbed hydrogen quantity as a function of the number of cycles, the cycling properties of the Mg-15 wt%Ni-5 wt%Fe₂O₃ alloy were investigated. The absorbed hydrogen quantity decreased as the number of cycles increased. The Ha value varied almost linearly with the number of cycles. The maintainability of absorbed hydrogen quantity at n=100 was 89.0% for the hydriding reaction time of 10 min. After the 150^th hydriding-dehydriding cycle, Mg, Mg₂Ni, Mg(OH)₂, MgO, and Fe were observed. The phases were analyzed by Rietveld analysis from the XRD patterns of the Mg-15 wt%Ni-5 wt%Fe₂O₃ alloy after 150 hydriding-dehydriding cycles. The crystallite size and strain of Mg were then estimated with the Williamson-Hall technique.