Enhancement of Hydrogen Storage in Destabilized LiNH2 with KMgH3 by Quick Conveyance of N-Containing Species

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• 作者：Yongtao Li ; Xiaoli Ding ; Feilong Wu ; Dalin Sun ; Qingan Zhang ; Fang Fang
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：January 28, 2016
• 年：2016
• 卷：120
• 期：3
• 页码：1415-1420
• 全文大小：393K
• ISSN：1932-7455

文摘

The advantage of potassium–magnesium bimetallic hydride as novel destabilization agent for LiNH₂ is demonstrated by a comparative study among MgH₂-, NaMgH₃-, and KMgH₃- systems. LiNH₂ combined with KMgH₃ not only results in a substantial decreased desorption temperature by >60 °C and suppression of NH₃ release but also enhances sorption kinetics two to five times in comparison with the single MgH₂ or NaMgH₃. A high reversible capacity of >65% is also achieved, even recharging under milder conditions. Through detailed structural analysis on the desorption products in various stages of these combined systems, we proposed a “self-concerted” reaction mechanism in which the in situ formed active MgH₂ and KH by KMgH₃ are involved in LiNH₂ decomposition. In addition, the remarkable promotion in conveyance of N-containing species by highly active KH compared with NaH is believed to be responsible for the superior destabilizing effect of KMgH₃ over NaMgH₃ in improving hydrogen sorption kinetics of LiNH₂.