Increased performance of hydrogen storage by Pd-treated LaNi4.7Al0.3, CaNi5 and Mg2Ni

In this study, a palladium treatment of LaNLi4.7Al0.3, CaNi5 and Mg2Ni is demonstrated to greatly improve the hydrogen storage performance of these intermetallic alloys. Mechanical grinding a small amount of palladium with the hydrogen storage alloys can lower the activation pressures to sub-atmospheric level at room temperature and significantly increase hydrogen absorption/desorption rates without changing the PCI behaviors. The PCI behavior of the palladium treated alloys was determined by a straight forward rule of mixtures calculations. The addition of palladium helps the disassociation of molecular hydrogen, and the mechanism of the treatment on the activation and hydrogen absorption/desorption of the alloys can be explained by hydrogen spillover for the absorption process and reverse hydrogen spillover for the desorption process.