Hydrogen storage performance of 5LiBH₄聽+聽Mg₂FeH₆ composite system

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• 作者：Shuaishuai Deng ; Xuezhang Xiao ; Leyuan Han ; Yun Li ; Shouquan Li ; Hongwei Ge ; Qidong Wang ; Lixin Chen ; ^{lxchen@zju.edu.cn}
• 关键词：Complex hydride ; LiBH4 ; Mg2FeH6 ; MgH2 ; FeB ; Hydrogen storage performance
• 刊名：International Journal of Hydrogen Energy
• 出版年：2012
• 期刊代码：42_03603199
• 类别：ch
• 出版时间：April, 2012
• 卷：37
• 期：8
• 页码：6733-6740
• 文件大小：1212 K

摘要

The hydrogen storage properties of 5LiBH₄聽+聽Mg₂FeH₆ reactive hydride composites for reversible hydrogen storage were investigated by comparing with the 2LiBH₄聽+聽MgH₂ composite in the present work. The dehydrogenation pathway and reaction mechanism of 5LiBH₄聽+聽Mg₂FeH₆ composite were also investigated and elucidated. The self-decomposition of Mg₂FeH₆ leads to the in situ formation of Mg and Fe particles on the surface of LiBH₄, resulting in a well dispersion between different reacting phases. The formation of FeB is observed during the dehydrogenation of 5LiBH₄聽+聽Mg₂FeH₆ composite, which might supplies nucleation sites of MgB₂ during the dehydrogenation process, but is not an ascendant catalyst for the self-decomposition of LiBH₄. And FeB can also transform to the LiBH₄ and Fe by reacting with LiH and H₂ during the rehydrogenation process. The dehydrogenation capacity for 5LiBH₄聽+聽Mg₂FeH₆ composite still gets to 6.5聽wt%even after four cycles. The X-ray diffraction analyses reveal the phase transitions during the hydriding and dehydriding cycle. The formed FeB in the composite maintains a nanostructure after four hydriding-dehydriding cycles. The loss of hydrogen storage capacity and de-/rehydrogenation kinetics can be attributed to the incomplete generation of Mg₂FeH₆ during the rehydrogenation process.