First-principles calculations of LaNi4Al-H solid solution and hydrides

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	First-principles calculations of LaNi4Al-H solid solution and hydrides
	R. J. Zhang ; Y. M. Wang ; D. M. Chen ; R. Yang ; K. Yang
刊名	Acta Materialia
	2006
卷号	54 期号:2 页码:465-472
关键词	electronic structure formation energy hydrogen storage capacity plane-wave pseudo-potential electronic-structure calculations neutron powder diffraction population analysis intermetallic compounds hydrogen absorption lani5 alloys stability energetics storage
ISSN号	1359-6454
中文摘要	First-principles calculations on the crystal and electronic structures of LaNi4AlHx (x = 1, 2, 3, 4, 4.5, 5 and 7) solid solution and hydrides have been performed by employing the plane-wave pseudo-potential method. Their equilibrium structures have been determined based on the calculated relative stabilities of hydrogen occupation sites in LaNi4Al and the rule of H-H separation to be no less than 0.21 nm, as well as the full geometry optimization. The covalency and ionicity analysis shows that the interaction between H and Ni is covalent and ionic; between H and La mainly ionic; between H and Al for x = 1, 2, 3 and 4 mainly ionic and for x = 4.5, 5 and 7 both covalent and ionic. The change of BOH-Nis (or Ionicity(H-La)(s)) with x can be a phenomenological indication of the experimental phase transformation for hydrogen solubility in LaNi4Al. The comparison of the calculated stability of hydrogen at interstices in LaNi4Al and LaNi5 shows that the possible hydrogen occupation sites in LaNi4Al are fewer than those in LaNi5. This contributes to the decrease of hydrogen storage capacity for LaNi4Al, which is illustrated by comparing the electron density distribution of LaNi4AlH7 with LaNi5H7. Except for H-H repulsions, the change of absorption energy with hydrogen content,. arising from the fact that an H atom tends to keep away from an Al atom, elucidates the limited maximum hydrogen content ill LaNi4Al. (c) 2005 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
原文出处	://WOS:000234785200017
公开日期	2012-04-14
内容类型	期刊论文
源URL	[http://ir.imr.ac.cn/handle/321006/34704]
专题	金属研究所_中国科学院金属研究所
推荐引用方式 GB/T 7714	R. J. Zhang,Y. M. Wang,D. M. Chen,et al. First-principles calculations of LaNi4Al-H solid solution and hydrides[J]. Acta Materialia,2006,54(2):465-472.
APA	R. J. Zhang,Y. M. Wang,D. M. Chen,R. Yang,&K. Yang.(2006).First-principles calculations of LaNi4Al-H solid solution and hydrides.Acta Materialia,54(2),465-472.
MLA	R. J. Zhang,et al."First-principles calculations of LaNi4Al-H solid solution and hydrides".Acta Materialia 54.2(2006):465-472.