A first principles study of the thermal stability of A(m)(MH(4))(n) light complex hydrides

IMR OpenIR

	A first principles study of the thermal stability of A(m)(MH(4))(n) light complex hydrides
	Y. L. Wang; S. Liu; L. J. Rong; Y. M. Wang
	2010
发表期刊	Journal of Physics-Condensed Matter
ISSN	0953-8984
卷号	22 期号:17
摘要	From the physical point of view, the cohesive energy of a reactant is preferable to its formation energy for characterizing its influence on the reaction processes from the reactants to the products. In fact it has been found that there is a certain correlation between the experimental hydrogen desorption temperature and the cohesive energy calculated by a first principles method for a series of A(m)(MH(4))(n) (A = Li, Na, Mg; M = Be, B, Al) light complex hydrides (including Na(2)BeH(4), Li(2)BeH(4), NaAlH(4), LiAlH(4), Mg(AlH(4))(2), LiBH(4) and NaBH(4)), which suggests that cohesive energy may be a useful physical quantity for evaluating the hydrogen desorption ability of complex hydrides, especially in cases when dehydrogenation products have unknown crystal structures, or may even be unknown. To understand this correlation more deeply, the ionic interaction between A and the MH(4) complex and the covalent interaction between M and H were calculated and their contributions to the cohesive energy evaluated quantitatively. The calculated results show that the covalent M-H interaction in the MH(4) complex is the dominant part of the cohesive energy E(coh) (up to more than 75%) and hardly changes during high-pressure structural transitions of A(m)(MH(4))(n). It was also found that low electronegativity of M or high electronegativity of A is responsible for the weak covalent M-H interaction and finally leads to the low thermodynamic stability of A(m)(MH(4))(n), suggesting that complex hydrides A(m)(MH(4))(n) can be destabilized by partial substitution of M (A) with an element with electronegativity lower (higher) than Ms (As). This conclusion has been confirmed by lots of experimental results and may be a useful guideline for the future design of new complex hydrides of the type A(m)(MH(4))(n).
部门归属	[wang, yuan-ming] chinese acad sci, inst met res, shenyang natl lab mat sci, shenyang 110016, peoples r china. [wang, yong-li; liu, shi; rong, li-jian] chinese acad sci, inst met res, mat special environm dept, shenyang 110016, peoples r china.;wang, ym (reprint author), chinese acad sci, inst met res, shenyang natl lab mat sci, 72 wenhua rd, shenyang 110016, peoples r china;ymwang@imr.ac.cn
关键词	Reversible Hydrogen Storage Doped Naalh4 Mechanochemical Synthesis Lithium Borohydride Metal Hydrides Ti Transition Libh4 Sc 1st-principles
URL	查看原文
文献类型	期刊论文
条目标识符	http://ir.imr.ac.cn/handle/321006/31550
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	Y. L. Wang,S. Liu,L. J. Rong,et al. A first principles study of the thermal stability of A(m)(MH(4))(n) light complex hydrides[J]. Journal of Physics-Condensed Matter,2010,22(17).
APA	Y. L. Wang,S. Liu,L. J. Rong,&Y. M. Wang.(2010).A first principles study of the thermal stability of A(m)(MH(4))(n) light complex hydrides.Journal of Physics-Condensed Matter,22(17).
MLA	Y. L. Wang,et al."A first principles study of the thermal stability of A(m)(MH(4))(n) light complex hydrides".Journal of Physics-Condensed Matter 22.17(2010).