Document Type
Article
Original Publication Date
2005
Journal/Book/Conference Title
Physical Review B
Volume
72
Issue
16
DOI of Original Publication
10.1103/PhysRevB.72.165101
Date of Submission
May 2015
Abstract
First-principles calculations based on density functional theory are carried out to understand the mechanisms responsible for hydrogen desorption from Ti-doped sodium-alanate (NaAlH4). While the energy needed to remove a hydrogen atom from NaAlH4 with Ti substituted either at the Na site or at Al site is found to be significantly lower than that from the pristine NaAlH4, the presence of Na vacancies is shown to play an even larger role: It is not only an order of magnitude smaller than that from Ti-doped sodium-alanate, but the removal of hydrogen associated with a Na vacancy is exothermic with respect to formation of H2 molecule. Furthermore, we show that the unusual stabilization of the magic AlH3 cluster in the vacancy containing sodium-alanate is responsible for this diminished value of the hydrogen-removal energy. It is suggested that this role of vacancies can be exploited in the design and synthesis of complex light-metal hydrides suitable for hydrogen storage.
Rights
Araújo, C. M., Li, S., Ahuja, R., et al. Vacancy-mediated hydrogen desorption in NaAlH4. Physical Review B, 72, 165101 (2005). Copyright © 2005 American Physical Society.
Is Part Of
VCU Physics Publications
Comments
Originally published by the American Physical Society at: http://dx.doi.org/10.1103/PhysRevB.72.165101