The synergistic effect of co-doping with Ti, Nb, and Ni on the hydrogen storage capacity of ZrCo

The effectiveness of element doping in enhancing the hydrogen storage performance of ZrCo alloys has been well established. However, the impact of single element doping is limited, and research on the synergistic effect of multi-element alloying remains relatively scarce. In this paper, the hydrogen storage properties of Zr0 & sdot;75Ti0 & sdot;125Nb0 & sdot;125Co0 & sdot;75Ni0.25 (ZTNCN) alloy were investigated using the first-principles method to explore the synergistic effect of Ti, Nb and Ni doping on ZrCo. The results indicate that the (-110) surface of ZTNCN undergoes significant reconstruction, leading to enhanced adsorption and dissociation of hydrogen on the surface. Moreover, there is no apparent dissociation barrier for H2, facilitating easier migration of H on the surface. The difference in atomic size leads to a variation in lattice interstices, resulting in a lower diffusion energy barrier for H compared to that of the ZrCoHx system. Through atomic substitution, the space within the 8e site becomes compressed, which makes the alloy exhibit improved resistance against disproportionation. Therefore, the synergistic effect of Ti, Nb, and Ni can greatly enhance hydrogen absorption and desorption kinetics in alloys and improve anti-disproportionation.