Al-N-Compounds – Possible Materials for Hydrogen Storage

Aluminum hydride (AlH₃) by itself has already been considered as a hydrogen storage material over 50 years ago based on its high volumetric (148 g H₂ L^-1) and gravimetric (10.1 wt.-%) hydrogen density. Based on its low decomposition temperature and light weight, research on AlH₃ confining the impractical re-hydrogenation conditions is still in progress. Attempts to stabilize AlH₃ with a Lewis base, such as an amine, lead to a significant reduction of the thermodynamic hydrogenation barrier of Al. This approach enables the hydrogenation at room temperature and reasonable pressures to generate amine AlH₃ adducts, called amino alanes. The influence of tertiary amines leads to stabilized phases under mild conditions offering promising properties for reversible hydrogenation.
 
References:
[1]   J. Ortmeyer, A. Bodach, L. Sandig-Predzymirska, B. Zibrowius, F. Mertens, M. Felderhoff, Direct Hydrogenation of Aluminum via Stabilization with Triethylenediamine: A Mechanochemical Approach to Synthesize the Triethylenediamine AlH₃ Adduct, ChemPhysChem, 2019, DOI: 10.1002/cphc.20180109
[2]     M.B. Ley, T. Bernert, J. Ruiz-Fuertes, R. Goddard, C. Fares, C. Weidenthaler, M. Felderhoff, The plastic crystalline A15 phase of dimethylaminoalane, [N(CH₃)₂–AlH₂]₃, Chem. Commun. 2016, 52, 11649–11652.