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Lithium aluminium hydride (LiAlH 4 ) has long been identified as a viable hydrogen storage material, due to its high attainable theoretical gravimetric hydrogen capacity of 7.9 wt%. The main impediment to its viability for technical application is its limitation for regeneration. Recently, solvent-mediated regeneration has been achieved at room temperature using dimethyl-ether, Me 2 O, although the reaction pathway has not been determined. This in situ multinuclear NMR spectroscopy study ( 27 Al and 7 Li) has confirmed that the Me 2 O-mediated, direct synthesis of LiAlH 4 occurs by a one-step process in which LiAlH 4 · x Me 2 O is formed, and does not involve Li 3 AlH 6 or any other intermediates. Hydrogenation has been shown to occur below ambient temperatures (at 0 °C) for the first time, and the importance of solvate adducts formed during the process is demonstrated. [ABSTRACT FROM AUTHOR]

A novel approach for confining LiBH 4 within a porous aluminium scaffold was applied in order to enhance its hydrogen storage properties, relative to conventional techniques for confining complex hydrides. The porous aluminium scaffold was fabricated by sintering NaAlH 4, which was in the form of a dense pellet, under dynamic vacuum. The final product was a porous aluminium scaffold with the Na and H 2 having been removed from the initial pellet. This technique contributed to achieving highly dispersed LiBH 4 particles that were also destabilised by the presence of the aluminium scaffold. In this study, the effectiveness of this novel fabrication method of confined/destabilised LiBH 4 was extensively investigated, which aimed to simultaneously improve the hydrogen release at lower temperature and the kinetics of the system. These properties were compared with the properties of other confined LiBH 4 samples found in the literature. As-synthesised samples were characterised using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) and Nitrogen Adsorption measurements. The hydrogen storage capacity of all samples was analysed using temperature programmed desorption in order to provide a comprehensive survey of their hydrogen desorption properties. The porous aluminium scaffold has a wide pore size distribution with most of the porosity due to pores larger than 50 nm. Despite this the onset hydrogen desorption temperature (T des ) of the LiBH 4 infiltrated into the porous aluminium scaffold was 200 °C lower than that of bulk LiBH 4 and 100 °C lower than that of nanosized LiBH 4 . Partial cycling could be achieved below the melting point of LiBH 4 but the kinetics of hydrogen release decreased with cycle number. [ABSTRACT FROM AUTHOR]