Hydrogen desorption/absorption properties of Li-Ca-N-H system

JOURNAL OF ALLOYS AND COMPOUNDS

卷:439

Article

Tokoyoda, Kazuhiko ; Hino, Satoshi ; Ichikawa, Takayuki ; Okamoto, Keisuke ; Fujii, Hironobu

关键词: hydrogen storage materials;    gas-solid reactions;    ball-milling;    calcium amide;   

DOI  :  10.1016/j.jallcom.2006.08.234

来源: Elsevier

【 摘 要 】

Hydrogen storage properties of two ball-milled composites of Ca(NH2)(2) + 2LiH and CaH2 + 2LiNH(2) were investigated as C - a series of searching studies of high performance hydrogen storage materials. About 4.5 mass% hydrogen is desorbed from about 100 degrees C and the thermal desorption profiles show a peak around 200 and 220 degrees C for the composites of CaH2 + 2LiNH(2) and Ca(NH2)(2) + 2LiH, respectively, under a helium flow at 5 degrees C/min heating rate without any NH3 emission within our experimental accuracy. The powder X-ray diffraction and infrared absorption spectroscopy indicated that the dehydrogenated states of both composites form an unknown imide phase after heating up to 400 degrees C, while the dehydrogenated states after heating up to 200 degrees C in vacuum are the mixed phases of Li2NH and CaNH. The rehydrogenated state for the ball-milled composite of CaH2 + 2LiNH(2) is transformed into the composite of Ca(NH2)(2) and 2LiH by repeating the dehydrogenation and rehydrogenation cycles at 180-200 degrees C. (c) 2006 Elsevier B.V. All rights reserved.

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