Structural and hydrogen absorption/desorption properties of Zr2(Co0.5Fe0.2Ni0.2V0.1) intermetallic alloy

The Zr2(Co0.5Fe0.2Ni0.2V0.1) intermetallic alloy was prepared by arc melting method and its physical properties and hydrogen storage performance were investigated. XRD analysis by Rietveld refinement and Mössbauer spectroscopy measurements revealed a multiphase crystal structure, in which the dominant phases are C16 Laves phase. The hydrogen-induced cracks, chemical composition, and elements distribution were analyzed by SEM and EDX mapping. The optimum conditions for the activation process, hydrogen absorption kinetics, cyclic durability performance, and disproportionation behavior were discussed. Zr2(Co0.5Fe0.2Ni0.2V0.1) alloy has a high absorption kinetic rate, with an activation energy of 10.11 kJ/mol, high hydrogen capacity (2.1 wt%) at room temperature, and good anti-disproportionation behavior (hydrogen pressure up to 8 bar and temperature below 783K). The hydrogen capacity decreased in the first three cycles (~25%) and then remained almost stable, which is likely caused by the high stability of hydride. The studied hydride has interesting features that can be considered for practical applications.