LAUSR

Abstract The strategy of partial substitution was adopted on the A-side of Y-Fe-Al alloys and Y-M-Fe-Al (M = Zr, Ti, V) quaternary alloys with C15 Laves phase were successfully prepared. Reversible hydrogen storage could be realized in these alloys without hydrogen-induced amorphization or disproportionation. The Y-M-Fe-Al alloys showed fast kinetics properties, completing de-/absorption processes within 500s. The Y0.9V0.1Fe1.7Al0.3 alloy could release the maximum amount of hydrogen with 0.79 wt%, which is almost twice as that of YFe1.7Al0.3 alloys. The improvement could be due to the increased desorption equilibrium pressure in Y-M-Fe-Al alloys, which increased from 0.168 to 1.203 atm. Neutron diffraction result indicated that H atoms occupied A2B2 tetrahedral sites in the C15 lattice. Thus, the size of the A2B2 tetrahedral sites and the hydride formation enthalpy of the substituted alloys were calculated, aiming to figure out a rough relation between them and the desorption equilibrium pressure, while providing some constructive suggestions on composition design in future research.