Hydrogen storage measurements in novel Mg-based nanostructured alloys produced via rapid solidification and devitrification
Hydrogen storage measurements in novel Mg-based nanostructured alloys produced via rapid solidification and devitrification
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DOI：
10.1016/j.ijhydene.2011.05.137
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发表时间：
2011-08-01
影响因子：
7.2
通讯作者：
Lass, Eric A.
中科院分区：
文献类型：
--
作者：
Lass, Eric A.
采用熔体快淬法制备了Mg_（85）Ni_（15-x）Mx（M = Y或La，x = 0或5）非晶和非晶-纳米晶前驱体，通过失透处理制备了纳米储氢材料。所有三种组合物在573 K下均表现出约5质量% H的最大存储容量。当在己烷中球磨30 mm时，该二元合金可以在473 K下活化（第一循环吸氢）。DSC实验表明，在该样品中的解吸开始于525 K，相比于560 K，当材料在573 K下活化时;这表明由于毛细作用的氢化物反应热力学的改善。添加Y和La通过减缓微观结构粗化来改善在二元合金的循环期间观察到的存储容量的退化。与二元合金相比，与La合金化还显示MgH 2和Mg 2NiH 4形成的反应焓分别降低约8 kJ/mol和5 kJ/mol;导致在473 K下H-2的一些脱附。改进的热力学进行了讨论，在不稳定的合金添加剂相对于新的平衡相。所提出的含La材料的包埋反应与先前报道的实验结果一致。版权所有（C）2011，氢能出版有限责任公司。由爱思唯尔有限公司出版。保留所有权利。
Nanostructured materials for hydrogen storage with a composition of Mg85Ni15-xMx (M = Y or La, x = 0 or 5) are formed by devitrification of amorphous and amorphous-nanocrystalline precursors produced by melt-spinning. All three compositions exhibit a maximum storage capacity of about 5 mass % H at 573 K. When ball-milled for 30 mm in hexanes, the binary alloy can be activated (first-cycle hydrogen absorption) at 473 K. DSC experiments indicate that desorption in this sample begins at 525 K, compared to 560 K when the material is activated at 573 K; which indicates an improvement in the hydride reaction thermodynamics due to capillarity effects. Additions of Y and La improve the degradation in storage capacity observed during cycling of the binary alloy by slowing microstructural coarsening. Alloying with La also shows a decrease of about 8 kJ/mol and 5 kJ/mol in the enthalpy of reaction for MgH2 and Mg2NiH4 formation, respectively, compared to the binary alloy; resulting in some desorption of H-2 at 473 K. The improved thermodynamics are discussed in terms of destabilization of the hydrides relative to new equilibrium phases introduced by alloying additions. The proposed hydriding reaction for the La-containing material is in agreement with previously reported experimental results. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.