from the conferences organized by TANGER Ltd.
The intermetallic compound LaNi₅ is a promising material for hydrogen storage. The ternary phase diagram La-Ni-Sn contains phases in which Ni atoms are substituted by Sn atoms, resulting in several different Sn/Ni ratios. In order to describe the La(Ni,Sn)5 system by phenomenological CALPHAD modelling, the energy of the completely substituted LaSn5 is needed. As this compound does not exist under ambient conditions, it is difficult to examine experimentally. Therefore, its properties were computed by quantum-mechanical calculations. Density functional theory (DFT) was employed to determine the structural characteristics of LaSn5, along with its electronic structure, energetics and thermodynamic stability as well as its mechanical stability. Our DFT calculations revealed a dramatic volume expansion upon this extreme case of substitution of all Ni atoms by Sn atoms, but the hexagonal structure remains stable without any significant distortions. The electronic calculations also revealed that the electronic density of states has a minimum at the Fermi level, which is in line with the lattice stability.
Keywords: La-Ni-Sn, quantum-mechanical calculations, stability, thermodynamics, elasticity© This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.