Preparation and properties of ball-milled MgH2/Al nanocomposites for hydrogen storage

Abstract

For reversible hydrogen storage properties of 17MgH2 + 12Al Mg17Al12 + 17H2, MgH2/Al nanocomposites (I)( IV) synthesized by ball milling of MgH2 and Al (or AlH3) were studied in connection with milling conditions. The milling processes consisting of two steps were effective to improve the hydrogen storage behavior; MgH2 was first milled with solutions of triethylaluminium (TEA) in hexane, followed by addition of Al and TEA solutions. The mixtures were further milled to yield the nanocomposite (III). In preparing the nanocomposite (IV), AlH3 was used instead of Al. For the nanocomposites (III) and (IV), it was proved by XRD, TDS, DSC and PCI that such ball-milling led to high dispersion of nanocrystalline MgH2 in Al and/or AlH3 matrix in the resulting nanocomposites. In DSC measured under a 0.1 MPa hydrogen atmosphere, the nanocomposites (III) and (IV) exhibited reversible H2 absorption and desorption at 493503 and 573593 K, respectively. © 2013 The Japan Institute of Metals and Materials.