Isomorphic transformation in undoped ZrCo hydrogen isotope storage alloy achieves high-temperature stable cycling

Abstract

The cycling stability of ZrCo hydrogen isotopes storage alloy in fusion reactor is crucial for their engineering applications. In this work, we completely studied the relationship between hydrogen-induced disproportionation reaction and phase transformation process during cycling to understand the capacity attenuation of the ZrCo alloy. And it is proved the reversible non-isomorphic transformation between α (ZrCo) phase and β (ZrCoH 3 ) leads to the cycling capacity attenuation. Thus, we establish an isomorphic transformation between α phase and α H phase through pressure control, which exhibits an extremely stable cycling capacity (1.0 H (f. u.)) even at a high-temperature (415 o C). It is worth mentioning that our work has achieved the stable hydrogen absorption and desorption cycle of ZrCo alloy at high temperatures without any element doping, which well maintains the original platform characteristics of ZrCo alloy and is of great significance for its engineering application.