Improved Hydrogen Storage Properties of LiBH4 Destabilized by in Situ Formation of MgH2 and LaH3

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• 作者：Yifan Zhou ; Yongfeng Liu ; Wei Wu ; Yu Zhang ; Mingxia Gao ; Hongge Pan
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：January 12, 2012
• 年：2012
• 卷：116
• 期：1
• 页码：1588-1595
• 全文大小：526K
• 年卷期：v.116,no.1(January 12, 2012)
• ISSN：1932-7455

文摘

A reactive composite of LiBH₄鈥?i>xLa₂Mg₁₇ was successfully prepared by means of mechanochemical reaction under 40 bar of H₂. It was found that MgH₂ and LaH₃ were readily formed in situ during high-pressure ball milling, and a strong dependency of hydrogen storage performance of the LiBH₄鈥?i>xLa₂Mg₁₇ composites on the content of La₂Mg₁₇ was observed. The as-prepared LiBH₄鈥?.083La₂Mg₁₇ composite under 40 bar of H₂ exhibits superior hydrogen storage properties as 6.8 wt % of hydrogen can be reversibly desorbed and absorbed below 400 掳C. It was also purposed that the self-decomposition of MgH₂ first occurred to convert into Mg with hydrogen release upon dehydrogenation and subsequently catalyzed the reaction of LiBH₄ and LaH₃ to liberate additional hydrogen along with the formation of LaB₆ and LiH. The in situ formed MgH₂ and LaH₃ provide a synergetic thermodynamic and kinetic destabilization on the de/hydrogenation of LiBH₄, which is responsible for the distinct reduction in the operating temperatures of the as-prepared LiBH₄鈥?i>xLa₂Mg₁₇ composites.