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.& COPY; 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

This study systematically investigated the effects of Sc/V/Ni substitution on the hydrogen diffusion and anti-disproportionation properties of ZrCo alloys and their hydrides through theoretical calculations. The results showed that doping V can improve hydrogen permeability and fast kinetics by reducing the migration barrier of absorbed H. However, Sc/Ni increased the migration barrier and V/Ni increased the formation energy of H in ZrCoH3 hydrides. These findings provide valuable insights for the design of high-performance ZrCo alloys.