Study of hydrogen storage properties of oxygen modified Ti- based AB(2) type metal hydride alloy

A multi component AB(2) type hydrogen storage intermetallic alloy (A = Ti0.85Zr0.15, B-2 = Mn1.22Ni0.22Cr0.2V0.3Fe0.06; was investigated in this work. The intermetallic specified above was modified by oxygen to yield the composition AB(2)O(0.05). The oxygen was introduced by adding TiO2 to the charge, with corresponding decrease of the Ti amount, followed by arc melting and annealing at the same conditions as for the oxygen free AB(2)-type alloy. The addition of oxygen to the alloy did not change much the PCT properties; the only difference was that the plateau pressure for the oxygen-modified alloy increased slightly. Both alloys have shown to be excellent candidates for H-2 storage, particularly for utility vehicles, due to their relatively high reversible H-2 storage capacity (1.6 wt%) and low plateau pressure at room temperature (<5 bar). The addition of oxygen improved hydrogen absorption kinetics in the AB(2) alloy allowing it to immediately absorb H-2 without activation while for the non-modified sample an incubation period (30 min) was observed at the same conditions. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.