Theoretical study of ZrCoH3 and the anti-disproportionation ability of alloying elements

First-principles calculations were performed to investigate the bonding characteristics of the undoped and doped ZrCoH3 and predict the anti-disproportionation abilities of alloying elements (i.e. Y, V, Nb, Ta, Zr, Cr, Mn, Ru, Rh, Pd and Zn). The binding between H and Zr (or its substitute elements) shows strong ionic and weak covalent feature, and that between H and Co (or its substitute elements) displays the opposite characteristic. The H diffusion process, the size of the 8e site and the corresponding ZrH distance were calculated, and the substitute elements of Zr (i.e. Nb, Ta and especially V) are predicted to be helpful to improve the ZrCo alloy against the hydrogen-induced disproportionation, and the substitute elements of Co may be not suitable.