A new Li-Al-N-H system for reversible hydrogen storage

Complex metal hydrides are considered as a class of candidate materials for hydrogen storage. Lithium-based complex hydrides including lithium alanates (LiAlH4 and Li3AlH6) are among the most promising materials owing to its high hydrogen content. In the present work, we investigated dehydrogenation/ rehydrogenation reactions of a combined system of Li3AlH6 and LiNH2. Thermogravimetric analysis (TGA) of Li3AlH6/3LiNH(2)/4 wt % TiCl3-1/3AlCl3 mixtures indicated that a large amount of hydrogen ( similar to 7.1 wt %) can be released between 150 degrees C and 300 degrees C under a heating rate of 5 degrees C/min in two dehydrogenation reaction steps. The results also show that the dehydrogenation reaction of the new material system is nearly 100% reversible under 2000 psi pressure hydrogen at 300 C. Further, a short-cycle experiment has demonstrated that the new combined material system of alanates and amides can maintain its hydrogen storage capacity upon cycling of the dehydrogenation/ rehydrogenation reactions.