Speaker
Description
The La-Ni-Sn compounds are considered promising candidates for future hydrogen-storage applications. Some phases from the La-Ni-Sn system have been insufficiently studied so far, and some critically important data are missing. We have, therefore, employed quantum-mechanical calculations combined with experiments to assess the stability of several La-Ni-Sn-H materials. Our study covers (i) binary La2Ni7 as well as La5Ni19 in the hexagonal and trigonal structure, (ii) ternary LaNi5-based ternaries La(Ni,Sn)5 with several Sn concentrations and a partial sublattice disorder, as well as (iii) hydrogen-containing quaternaries HLaNiSn and H2LaNiSn. We found La2Ni7 stable thermodynamically and mechanically but not dynamically due to the presence of imaginary-phonon modes. The two La5Ni19 phases are also thermodynamically and mechanically stable, and their structural, electronic, thermodynamic, magnetic, and elastic characteristics are very similar. Regarding the LaNi5-based ternaries La(Ni,Sn)5, we identified a miscibility gap with respect to the tin content, which was confirmed experimentally. Lastly, the two hydrogen-containing quaternaries HLaNiSn and H2LaNiSn were computed thermodynamically, mechanically and dynamically stable featuring specific high-energy hydrogen-related phonon states.
Acknowledgments
This study is a part of the project No. CZ.02.01.01/00/22_008/0004631 entitled “Materials and technologies for sustainable development” within the Jan Amos Komensky Operational Program financed by the European Union and from the state budget of the Czech Republic. Computational resources were made available by the Ministry of Education, Youth and Sports of the Czech Republic under the Project e-INFRA CZ (ID:90254) at the IT4Innovations National Supercomputing Center, the MetaCentrum and CERIT-SC. Access to the CERIT-SC computing and storage facilities provided by the CERIT-SC Center, under the programme "Projects of Large Research, Development, and Innovations Infrastructures" (CERIT Scientific Cloud LM2015085) and access to CESNET storage facilities provided by the project “e-INFRA CZ” under the programme “Projects of Large Research, Development, and Innovations Infrastructures” LM2023054) is acknowledged.
