Cr substitution enhances Zr0.95V0.05Co1-xCrx(x = 0–0.15) alloy’s hydrogen isotope storage and anti hydrogen-induce disproportionation

Abstract

The ZrCo alloy, considered an ideal candidate material for hydrogen (or its isotope) storage to replace uranium in the ITER, faces challenges due to its susceptibility to hydrogen-induced disproportionation, which leads to a diminished cycling life. To address this, we investigated the substitution of V and Cr for Zr and Co. Our study reveals that this substitution not only refines the grain size and expands the lattice constant but also significantly enhances the kinetics of hydrogen absorption. Notably, the Zr_0.95V_0.05Co_0.85Cr_0.15 alloy demonstrates a remarkable 98.8 % reduction in the time required to absorb 90 % of its full capacity compared to ZrCo. This alloy also exhibits superior isotope effects under H₂ and D₂ environments, along with lower enthalpy and entropy for dehydrogenation, contributing to a reduced dehydrogenation temperature and enhanced resistance to disproportionation. After 50 cycles of hydrogen absorption and desorption, the hydrogen storage capacity of Zr_0.95V_0.05Co_0.85Cr_0.15 alloys decreases by only 5.7 %, significantly outperforming other reference samples and demonstrating its exceptional anti-disproportionation capability. These results indicate that the Zr_0.95V_0.05Co_0.85Cr_0.15 alloy exhibits the best resistance to hydrogen-induced disproportionation. Moreover, post-50 cycling analysis confirms that the phase of the alloy is still dominated by the ZrCo phase, indicating its excellent structural stability. Our findings offer valuable insights into optimizing ZrCo-based alloys for enhanced hydrogen storage performance and cycling stability, providing potential references for advancements in hydrogen isotope storage materials design.