Ab Initio Computational Studies of Mg Vacancy Diffusion in Doped MgB2 Aimed at Hydriding Kinetics Enhancement of the LiBH4 + MgH2 System

作者：Zhong Yang; Zhu Hong; Shaw Leon L^*; Ramprasad R

来源：Journal of Physical Chemistry C, 2010, 114(49): 21801-21807.

DOI：10.1021/jp1066567

We report an ab initio density functional theory (DFT) study that investigates the effect of transition metal dopants on diffusion of Mg vacancies in MgB2. This study has implications for the diffusion-controlled hydriding kinetics of the technologically important LiBH4 + MgH2 hydrogen storage system. The first-principles calculation reveals that the solubility of M (M = Ni, Mn, V, Ti, Sc, and Y) in MgB2 and the migration barriers of Mg vacancies are dictated by the dopant's atomic radius, whereas the formation energies of Mg vacancies are strongly affected by both the dopant's atomic radius and charge distribution. Mn, Sc, and Y are found to have the potential to enhance the diffusion rate of Mg, whereas V and Ti are poor dopants in enhancing the diffusion rate of Mg in MgB2. The findings in this study are consistent with existing experimental results.

• 出版日期2010-12-16