Ion exchanged aluminium hydrides were prepared by a mechanochemical ball milling method with a variation of milling time using Mg, Ca chloride and Na, Li aluminium hydride in the absence of any solvents. For the purpose of comparison, ion exchanged aluminium hydrides were also prepared by a metathesis reaction method in the presence of diethyl ether. The formation of magnesium aluminium hydride (Mg(AlH_4)_2) and magnesium aluminium hydride - diethyl ether (Mg(AlH_4)_2·Et_2O) adduct was confirmed by XRD measurements. In both magnesium aluminium hydrides, hydrogen evolution occurred in the first step decomposition. The starting temperature for hydrogen evolution of the solvent-free magnesium aluminium hydride decreased with increasing milling time, and the amount of hydrogen evolution of the solvent-free magnesium aluminium hydrides increased with increasing milling time. Also, the starting temperature for hydrogen evolution of the Mg(AlH_4)_2·Et_2O adduct was much higher than that of the solvent-free Mg(AlH_4)_2. The addition of a small amount of titanium to the solvent-free aluminium hydrides had a significant effect on the hydrogen evolution performance. The addition of a small amount of titanium reduced the hydrogen evolution temperature and had a better performance of hydrogen restoration after hydrogen evolution. However, the maximum amount of hydrogen evolution of the titanium-doped aluminium hydrides were smaller than that of the solvent-free Mg(AlH_4)_2.
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