Improved dehydrogenation properties of lithium alanate (LiAlH4) doped by low energy grinding

LiAlH4 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 LiAlH4 with transition metals in order to improve its dehydrogenation kinetics. However, very often it was found that LiAlH4 starts dehydrogenating already during doping, thereby, reducing the usable hydrogen storage capacity considerably.In this study, LiAlH4 was doped by low-energy grinding with different transition metal chlorides (ZrCl4, TiCl3 and NiCl2). Thus, unwanted dehydrogenation during doping could be prevented. The positive effect of the dopants on promoting the dehydrogenation of LiAlH4 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 LiAlH4, the weight change was monitored at room temperature up to seven months.

► Transition metal (TM)-doping of LiAlH4 by low-energy grinding prevents dehydrogenation during preparation.
► Onset temperature and kinetics of TM-doped LiAlH4 were studied systematically under a hydrogen pressure of 1 bar.
► Long-term storability of TM-doped LiAlH4 at RT was studied up to 7 months.