We use ab initio methods and neutron inelastic scattering (NIS) to study the structure, energetics, and dynamics of pure and Ti-doped sodium alanate (NaAlH_4), focusing on the possibility of substitutional Ti doping. The NIS spectrum is found to exhibit surprisingly strong and sharp two-phonon features. The calculations reveal that substitutional Ti doping is energetically possible. Ti prefers to substitute for Na and is a powerful hydrogen attractor that facilitates multiple Al--H bond breaking. Our results hint at new ways of improving the hydrogen dynamics and storage capacity of the alanates.
@article{arxiv.cond-mat/0401161,
title = {Multi-phonon scattering and Ti-induced hydrogen dynamics in sodium alanate},
author = {Jorge Iniguez and T. Yildirim and T. J. Udovic and E. H. Majzoub and M. Sulic and C. M. Jensen},
journal= {arXiv preprint arXiv:cond-mat/0401161},
year = {2009}
}
Comments
5 pages, with 4 postscript figures embedded. Uses REVTEX4 and graphicx macros