Exploring the Hydrogen-Induced Amorphization and Hydrogen Storage Reversibility of Y(Sc)(0.95)Ni(2) Laves Phase Compounds

Rare-earth-based AB(2)-type compounds with Laves phase structure are readily subject to hydrogen-induced amorphization and disproportionation upon hydrogenation. In this work, we conducted the Sc alloying on Y(0.95)Ni(2) to improve its hydrogen storage properties. The results show that the amorphization degree of Y(0.95)Ni(2) deepens with the increasing hydrogenation time, pressure, and temperature. The Y(Sc)(0.95)Ni(2) ternary compounds show a significant improvement in reversibility and dehydriding thermodynamics due to the reduced atomic radius ratio R(A)/R(B) and cell volume. Hydrogen-induced amorphization is fully eliminated in the Y(0.25)Sc(0.7)Ni(2). The Y(0.25)Sc(0.7)Ni(2) delivers a reversible hydrogen storage capacity of 0.94 wt.% and the dissociation pressure of 0.095 MPa at the minimum dehydrogenation temperature of 100 °C.