Theoretical analysis of β-LaNi5Hx (5≤x≤8): structure and energetics
(National Development Center of Hi-Tech Green Materials, Beijing Institute of Technology, Beijing 100081, China)
Abstract: The calculations of total energy, band structure, and electronic density of states and Mulliken population analysis of β-LaNi5Hx(5≤x≤8) were performed by adopting the method of total energy based on the density functional theory. The augmented plane wave function was selected as the basis set in combination with ultra-soft pseudo-potential technology. The influence of the amount of H absorbed in alloys was discussed in terms of geometry, electronic structure and thermodynamic derived from calculated results. The results show that the amount of H absorbed and the preferred site occupation of the absorbed hydrogen atoms were controlled by the position of H-bands and the energy gap between H-bands and conduction bands. The β-phase hydrides of LaNi5 are most stable when hydrogen atom capacity coating in the range of 6-7.
Key words: LaNi5 hydride; geometry; electronic structure; heat of formation