Improved dehydrogenation properties of lithium alanate (LiAlH 4) doped by low energy grinding

LiAlH 4 is an attractive hydrogen storage material because of its high gravimetric hydrogen storage capacity of 10.5 wt.%. There are various reports in the literature on doping LiAlH 4 with transition metals in order to improve its dehydrogenation kinetics. However, very often it was found that LiAlH 4 starts dehydrogenating already during doping, thereby, reducing the usable hydrogen storage capacity considerably. In this study, LiAlH 4 was doped by low-energy grinding with different transition metal chlorides (ZrCl 4, TiCl 3 and NiCl 2). Thus, unwanted dehydrogenation during doping could be prevented. The positive effect of the dopants on promoting the dehydrogenation of LiAlH 4 was systematically studied by thermal analysis. In addition, the crystal phases were characterized by X-ray diffraction. In view of long-term storability of suchlike doped LiAlH 4, the weight change was monitored at room temperature up to seven months.