A comparative study was performed on four LiBH4-based hydrogen storage composites 2LiBH(4) + MgX2 and 6LiBH(4) + CaX2 (X = H and F). The composites with fluorides and those with corresponding hydrides exhibited similar hydrogen storage properties. The dehydrogenation of 2LiBH(4) + MgF2 demonstrated a strong dependence on the hydrogen back pressure, similar to that of 2LiBH(4) + MgH2. The reversible hydrogen storage of 2LiBH(4) + MgF2 was achieved under a back pressure of 5 bar at 450 degrees C. Dehydrogenation under lower H-2 pressures resulted in the production of Mg and thus a partial reversibility. In contrast, both 6LiBH(4) + CaH2 and 6LiBH(4) + CaF2 revealed reversible hydrogen storage properties regardless of the hydrogen back pressure. The structural difference between MgB2 and CaB6 may account for the observed differences in hydrogen storage properties of the Mg- and Ca-containing LiBH4 reactive composites. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.