Hydrogen storage properties of AB2 type Ti–Zr–Cr–Mn–Fe based alloys

This investigation explores the solid-state hydrogen storage properties of two series of hydrogen storage alloys: (Ti0.85Zr0.15)xMn0.8CrFe0.2 (x = 1.00∼1.10) and (Ti0.85Zr0.15)1.02MnyCr1.8-yFe0.2 (y = 1.00∼0.40) alloys. These alloys exhibit a single C14-Laves phase structure and demonstrate promising capabilities for solid-state hydrogen storage. The (Ti0.85Zr0.15)xMn0.8CrFe0.2 (x = 1.00∼1.10) alloys display an increased hydrogen absorption capacity and a reduced plateau pressure at higher super-stoichiometric ratios of x. When x = 1.10, the alloy achieves a maximum capacity of 1.86 wt%. The hydrogen storage capacity of the (Ti0.85Zr0.15)1.02MnyCr1.8-yFe0.2 (y = 1.00∼0.40) alloys diminishes as the value of y decreases. Furthermore, the hydrogen absorption plateau pressure and hysteresis factor of the alloys increase with an escalating Mn/Cr ratio. The analysis of cyclic stability reveals that the primary factor contributing to poor cycling stability of the (Ti0.85Zr0.15)1.02Mn0.4Cr1.4Fe0.2 alloy is the compositional decomposition, rather than pulverization or alterations in the phase structure.