Investigations on gaseous hydrogen storage performances and reactivation ability of as-cast TiFe1-xNix (x=0, 0.1, 0.2 and 0.4) alloys

Abstract

In this paper, Fe is partly substituted by Ni for improving the hydrogen storage properties of the TiFe alloy, such as the activation performance, hydrogen storage capacity, reactivation ability, optimum temperature range, thermodynamics and kinetics. The as-cast TiFe alloy contains the majority phase of TiFe and the minority phases of Ti2Fe and TiFe2. Increasing Ni content causes the majority phase of TiFe to increase firstly and then decrease again. The activation temperature reduces from 573 K for the TiFe alloy to 523 and 443 K for the TiFe0·8Ni0.2 and TiFe0·6Ni0.4 alloys respectively. Substituting Fe with Ni partly can lower the platform pressure for the P-C-T curves and increase the dehydrogenation enthalpy (ΔHdes). The TiFe0·8Ni0.2 alloy possesses the highest hydrogenation capacity. Adding Ni also is beneficial to expand the optimum temperature range, corresponding to the hydrogenation capacity higher than 0.800 wt%, which is 313–383, 313–503 and 313–573 K for the TiFe1-xNix (x = 0.1, 0.2 and 0.4) alloys, respectively. All the alloys can be activated again at 573 K after being exposed to air for 5 min.