Enhanced hydrogen storage properties of 2LiNH(2)/MgH2 through the addition of Mg(BH4)(2)

摘要

The Li-Mg-N-H system has been widely considered as one of the most promising candidates for on-board hydrogen storage due to its high reversible hydrogen capacity, good reversibility, and favorable thermodynamics. In this study, we show that the hydrogen storage properties of the 2LiNH(2)/MgH2 sample can be further promoted through the addition of Mg(BH4)(2). The onset temperature for the dehydrogenation of the 2LiNH(2)/MgH2/0.1Mg(BH4)(2) sample is only 80 degrees C, showing a reduction of around 50 degrees C with respect to the 2LiNH(2)/MgH2 sample. The hydrogenation tests indicate that the dehydrogenated 2LiNH(2)/MgH2/0.1Mg(BH4)(2) sample could fully absorb about 5.0 wt% of hydrogen at 180 degrees C and 48 bar hydrogen pressure in 2 h, while only 3.5 wt% of hydrogen was recharged into the dehydrogenated 2LiNH(2)/MgH2 sample at 200 degrees C and 48 bar hydrogen pressure even within 30 h. The investigation on the structural changes and the cycling absorption/desortion of hydrogen was also performed. Moreover, the thermal conductivity of the as-milled 2LiNH(2)/MgH2 sample is almost doubled after the addition of 0.1Mg(BH4)(2) without any loss of hydrogen capacity. (C) 2017 Elsevier B.V. All rights reserved.