from the conferences organized by TANGER Ltd.
The LaNi5 compound is a prototypical hydrogen-storage material intended for future energy applications. Some of its properties have not been sufficiently studied so far and some critically important data is missing. In particular, there are conflicting literature reports related to the substitution of Ni atoms with Sn atoms in LaNi5. We have employed quantum-mechanical calculations implementing the density functional theory (DFT) within the generalized gradient approximation (GGA) to determine the ground-state structural, electronic, thermodynamic, and vibrational properties of several substituted La(Ni,Sn)5 phases. Our computational cell containing 48 atoms allowed for simulating different Sn/Ni ratios as well as different configurations of substituting Sn atoms. Our results indicate that the free energy of formation is concave and there is a miscibility gap and a decomposition into two phases, one with a low and one with a high Sn concentration. Our theoretical study was complemented by experiments which found a similar miscibility gap, too.
Keywords: miscibility, tin, alloys, phonons© 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.