The influence of dopants Ti and Ni on the dehydrogenation properties of NaAlH4 was studied by means of first principles. It was shown that Ti tended to occupy the Al site in NaAlH4, while the interstitial site was favourite for Ni to occupy. Analysis of the electronic structure reveals that the [AlH4] ligand was distorted by the strong interaction between the dopant Ti and its nearest neighbouring Al atoms when Ti occupied the Al site. Therefore, the dehydrogenation properties of NaAlH4 were improved. The influence of Ni on the dehydrogenation properties of NaAlH4 was relatively small than that of Ti. The stability of the [AlH4] ligand was affected only if the Ni occupied the interstitial site. In general, the influence of Ti on the dehydrogenation properties of NaAlH4 is stronger than that of Ni, which is consistent with the experimental findings.

Key words: first-principles, NaAlH4, dehydrogenation property