Hydrogen desorption/absorption properties of Li-Ca-N-H system
JAllCompd_439_1-2_337.pdf 435 KB
Hydrogen storage materials
Hydrogen storage properties of two ball-milled composites of Ca(NH2)2+2LiH and CaH2+2LiNH2 were investigated as a series of searching studies of high performance hydrogen storage materials. About 4.5 mass% hydrogen is desorbed from about 100 °C and the thermal desorption profiles show a peak around 200 and 220 °C for the composites of CaH2+2LiNH2 and Ca(NH2)2+2LiH, respectively, under a helium flow at 5 °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 °C, while the dehydrogenated states after heating up to 200 °C in vacuum are the mixed phases of Li2NH and CaNH. The rehydrogenated state for the ball-milled composite of CaH2+2LiNH2 is transformed into the composite of Ca(NH2)2 and 2LiH by repeating the dehydrogenation and rehydrogenation cycles at 180~200 °C.
Journal of Alloys and Compounds
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Copyright (c) 2007 Elsevier B.V.
Natural Science Center for Basic Research and Development
Institute for Advanced Materials Research