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Formation and decomposition of AlH3 in the aluminum-hydrogen systemOct. 20, 2008AlH3 is a promising material for hydrogen storage due to its large gravimetric and volumetric hydrogen content and has been prepared only by organometallic synthesis. Possibility of a direct hydrogenation of aluminum at high pressure has been suggested in the literature. However aluminum is passivated in air to form a chemically stable oxide layer, hydrogenation is prevented. Hydrogenation of pristine aluminum has failed. Here, in situ x-ray diffraction measurements for the Al-H system were conducted to investigate the hydrogenation and dehydrogenation reaction of aluminum immersed in hydrogen fluid. Pristine aluminum was hydrogenated at 8.9 GPa and 600 �C. The cyclic dehydrogenation and hydrogenation of the AlH3 were measured by the in situ x-ray measurement. Transparent single crystals were recovered at ambient conditions. Improvement of thermodynamical property of AlH3 by atomic substitution is expected to be achieved through the high pressure technique. These results will be helpful to develop hydrogen storage materials. This result was published online in Applied Physics Letters, Vol. 93, Issue 15, Oct. 17, 2008. This work was supported by New Energy and Industrial Technology Development Organization (NEDO) under �Advanced Fundamental Research Project on Hydrogen Storage Materials� |
