Hydrogen storage properties in Ti catalyzed Li-N-H system
Hydrogen storage properties in Ti catalyzed Li-N-H system
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DOI：
10.1016/j.jallcom.2004.11.110
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发表时间：
2005-12-08
影响因子：
6.2
通讯作者：
Fujii, H
中科院分区：
文献类型：
--
作者：
Ichikawa, T;Hanada, N;Fujii, H
以LiNH 2 + LiH Li 2NH + H-2表示的Li-N-H体系由于具有大量的可逆氢（6.5wt%），有望成为储氢材料的有希望的候选者，令人满意的快速动力学和相对小的焓变。本文从三个不同的角度研究了Li-N-H体系的储氢性能。首先，我们声称，含有少量（1摩尔%）氯化钛（TiCl 3）的氨基化锂（LiNH 2）和氢化锂（LiH）的球磨1：1混合物显示出上级的储氢性能;大量的H-2气体在150至250 ℃的温度范围内以5 ℃/n-dn的加热速率解吸，并且其显示出优异的可逆性。其次，我们阐明了上述放氢反应是由两类基元反应组成的：一类是2LiNH（2）分解为Li 2NH并放出氨（NH3）;另一种是NH3与LiH反应生成LiNH 2和H2-，表明NH3在H2-脱附反应中起重要作用。最后，我们检查了LiH和LiOH的反应，以澄清将产物暴露于空气的影响。这是因为LiH和LiNH 2暴露于空气中容易生成LiOH。LiH和LiOH之间的反应表明更好的动力学，但较差的耐久性和额外的H2解吸，由于转化为Li 2 O。(c)2005 Elsevier B. V.保留所有权利。
The Li-N-H system expressed by LiNH2 + LiH Li2NH + H-2 can be expected as a promising candidate for the hydrogen storage materials because of possessing a large amount of reversible hydrogen (6.5 wt.%), a satisfactorily fast kinetics and a relatively small enthalpy change. In this work, we investigated the hydrogen storage properties of the Li-N-H system from three different points of view. Firstly, we claim that the ball milled 1: 1 mixture of lithium amide (LiNH2) and lithium hydride (LiH) containing a small amount (I mol %) of titanium chloride (TiCl3) shows superior hydrogen storage properties; a large amount of H-2 gas desorbs in the temperature range from 150 to 250 degrees C at a heating rate of 5 degrees C/n-dn and it reveals an excellent reversibility. Secondly, we clarify that the above hydrogen desorption reaction is composed of two kinds of elementary reactions: The one is that 2LiNH(2) decomposes to Li2NH and emits ammonia (NH3). The other is that the emitted NH3 reacts with LiH and transforms into LiNH2 and H-2, indicating that NH3 plays an important role on this H-2 desorption reaction. Finally, we examined the reaction of LiH and LiOH to clarify the influence of exposing the product to air. This is because due to the fact that LiOH is easily produced by exposing LiH and LiNH2 to air. The reaction between LiH and LiOH indicated better kinetics but worse durability and an extra H2 desorption due to transforming into Li2O. (c) 2005 Elsevier B.V. All rights reserved.