Hydrogen diffusion and anti-disproportionation properties in ZrCo alloys: The effect of Sc, V, and Ni dopants

The use of ZrCo alloys as hydrogen isotope storage materials is limited by the significant reduction of storage capacity caused by disproportionation reaction. In this study, the effects of Sc/V/Ni substitution on the hydrogen diffusion and anti-disproportionation properties of ZrCo alloys and their hydrides were systematically investigated by theoretical calculations. The doping of V reduces the migration barrier of absorbed H at different octahedral sites, leading to improved hydrogen permeability and fast kinetics. For ZrCoH₃ hydrides, V/Ni dopant increases the formation energy of H in 8e site, while Sc has opposite effect. Additionally, the migration barrier for H away from 8e site to its nearby 4c₂ site is obviously lowered by V, but is increased by Sc/Ni. These results indicate that V substitution can effectively improve hydride anti-disproportionation capability, which deepens the understanding of experimental phenomena, and sheds valuable light on the design of ZrCo alloys with high performance.