Hydrogen storage properties of non-stoichiometric Zr_0.9Ti_xV₂ melt-spun ribbons

Melt-spinning technique is applied to produce non-stoichiometric Zr_0.9Ti_xV₂ (x = 0, 0.2, 0.3, 0.4) ribbons to illustrate the effect of rapidly quenched solidification and non-stoichiometry on microstructures, phase formation and hydrogenation properties. Phase structure investigation by powder X-ray diffraction shows the C15-type ZrV₂ Laves phase, V-BCC, β-Zr and a small amount of Zr₃V₃O in Zr_0.9Ti_xV₂ melt-spun ribbons, and ZrV₂ phase decreases while β-Zr phase increases gradually with increasing Ti content. Activation behavior, hydrogenation kinetics, pressure-composition-temperature (PCT) characteristics, thermodynamics parameters and hydrides constituent of Zr_0.9Ti_xV₂ melt-spun ribbons are compared. Ribbons are easy to be activated and exhibit fast hydrogen absorption kinetics on account of the increased specific surface area and grain refinement. However, the initial hydrogen absorption rate decreases obviously with the increase of Ti content. Meanwhile, the slope of PCT plateau decreases and the stability of metal hydrides increases, which result from the increase of β-Zr content and unit cell volume of the dominant phase with increasing Ti content.