Alane (AlH₃) has a high weight percent hydrogen storage (10.1 wt. %) and a high volumetric storage density which makes it appealing for vehicular use. The major problem with bulk alane is that once hydrogen is desorbed from the material the remaining bulk aluminium requires over 2 GPa of hydrogen pressure to return to AlH₃.^1,2 An investigation of alane nanoparticles has been undertaken to determine if there is a relationship between particle size and H₂ absorption pressure.

Alane nanoparticles have been synthesised via a mechanochemical method³ with a focus on tuning particle size (and obtaining a pure product) to study the sorption conditions for hydrogen in the aluminium-alane nanoparticle system. Alane is synthesised via the following reaction:

3LiAlH₄ + AlCl₃ → 4AlH₃ + 3LiCl

A variety of solvents have been investigated in order to remove the LiCl by-product phase leaving pure AlH₃ nanoparticles. A range of techniques including x-ray diffraction (XRD), transmission electron microscopy (TEM), small angle x-ray scattering (SAXS) and hydrogen sorption measurements have been utilised to characterise the alane nanoparticles.

References
1. Baranowski, B. & Tkacz, M. (1983). Zeitschrift für Physikalische Chemie 135, 27-38.
2. Konovalov, S. K. & Bulychev, B. M. (1995). Inorganic Chemistry 34, 172-175.
3. Brinks, H. W., Istad-Lem, A. & Hauback, B. C. (2006). Journal of Physical Chemistry B 110, 25833-25837.