First-principles calculations of crystal and electronic structures and thermodynamic stabilities of La-Ni-H, La-Ni-Al-H and La-Ni-Al-Mn-H hydrogen storage compounds

IMR OpenIR

	First-principles calculations of crystal and electronic structures and thermodynamic stabilities of La-Ni-H, La-Ni-Al-H and La-Ni-Al-Mn-H hydrogen storage compounds
	Liu, GL; Chen, DM; Wang, YM; Yang, K; Wang, YM (reprint author), Chinese Acad Sci, Inst Met Res, Shenyang 110016, Peoples R China.
	2016-07-27
发表期刊	INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
ISSN	0360-3199
卷号	41 期号:28 页码:12194-12204
摘要	First-principles density functional theory (DFT) and lattice dynamical theory (LDT) calculations have been used to investigate the crystal and electronic structures and thermodynamic stabilities of La-Ni-H, La-Ni-Al-H and La-Ni-Al-Mn-H hydrogen storage compounds. We find that all these compounds studied are dynamically stable. For LaNi3.8Al1.2-xMnxH (x = 0.2, 0.4, 0.6) hydrides, Al only substitutes Ni at 3g0 site, H occupies 12n tetrahedral site. The structural optimizations indicate that Mn prefers to substitute Ni at 3g1 site. Mn substitutions for Ni and Al decrease their stabilities. A detailed analysis of bonding interactions reveals that the covalent bonds of H with one Ni or Mn at 3g1 site and two Ni at 2c site are mainly responsible for the stabilities of these compounds. We also present a comprehensive investigation of phonon spectra and vibrational thermodynamics of LaNi5-xAlxH (x = 0, 0.25, 0.5, 0.75 and 1) and LaNi3.8Al1.2-xMnxH (x = 0.2, 0.4 and 0.6). We find that all phonon vibrations have contribution to their vibrational enthalpies; in contrast, the low-frequency phonon vibrations mainly dominate their vibrational entropies. The calculated accuracy of low-frequency phonon vibrations is closely related to crystal symmetry, supercell size and atomic distribution in selected supercell. Generally, calculated enthalpies are more accurate than calculated entropies with respect to their experimental values. We present in the current research a first-principles method to predict the variation of enthalpy with hydrogen content at hydrogenation or dehydrogenation plateau and then to identify the so-called plateau enthalpy of each La Ni based hydrogen storage alloy. By using this method, we find that the partial substitutions of Ni by Al decrease the so-called plateau enthalpy but impair the hydrogen storage capacity obviously, while Mn and Al substitutions for Ni not only decrease the so-called plateau enthalpy but also extend the plateau length. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
部门归属	[liu, guoliang ; chen, demin ; wang, yuanming ; yang, ke] chinese acad sci, inst met res, shenyang 110016, peoples r china ; [liu, guoliang] univ chinese acad sci, beijing 100049, peoples r china
关键词	Formation Energy Stability Bonding Interactions Thermodynamic Properties
学科领域	Chemistry, Physical ; Electrochemistry ; Energy & Fuels
资助者	National Natural Science Foundation of China [51271176]
收录类别	sci
语种	英语
WOS记录号	WOS:000380627600035
引用统计	被引频次：6[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://ir.imr.ac.cn/handle/321006/76320
专题	中国科学院金属研究所
通讯作者	Chen, DM; Wang, YM (reprint author), Chinese Acad Sci, Inst Met Res, Shenyang 110016, Peoples R China.
推荐引用方式 GB/T 7714	Liu, GL,Chen, DM,Wang, YM,et al. First-principles calculations of crystal and electronic structures and thermodynamic stabilities of La-Ni-H, La-Ni-Al-H and La-Ni-Al-Mn-H hydrogen storage compounds[J]. INTERNATIONAL JOURNAL OF HYDROGEN ENERGY,2016,41(28):12194-12204.
APA	Liu, GL,Chen, DM,Wang, YM,Yang, K,&Wang, YM .(2016).First-principles calculations of crystal and electronic structures and thermodynamic stabilities of La-Ni-H, La-Ni-Al-H and La-Ni-Al-Mn-H hydrogen storage compounds.INTERNATIONAL JOURNAL OF HYDROGEN ENERGY,41(28),12194-12204.
MLA	Liu, GL,et al."First-principles calculations of crystal and electronic structures and thermodynamic stabilities of La-Ni-H, La-Ni-Al-H and La-Ni-Al-Mn-H hydrogen storage compounds".INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 41.28(2016):12194-12204.