De-/rehydrogenation properties and reaction mechanisms of 4LiBH4-LiAlH4-MgF2 system

In this paper, the 4LiBH(4)-LiAlH4-MgF2 ternary reactive system was constructed to investigate its de-/rehydrogenation properties and reaction mechanisms. It was found that the 4LiBH(4)-LiAlH4-MgF2 system starts to release hydrogen at about 100 degrees C and totally desorbs about 8.9 wt.% of hydrogen up to 480 degrees C. These dehydrogenation properties are much better than those of the 2LiBH(4)-LiAlH4, 2LiBH(4)-MgF2 and 4LiBH(4)-LiAlH4-MgF2 systems. Thermal dehydrogenation of the 4LiBH(4)-LiAlH4-MgF2 system proceeds mainly in three steps with MgAlB4, LiH and LiF as the desorbed products. After rehydrogenation at 400 degrees C under 6 MPa hydrogen pressure, about 4.9 wt.% of hydrogen can be desorbed during the second dehydrogenation process. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.