Reversible hydrogen storage in metal-doped Mg-LiBH4 composites

Composite powders of Mg50Ni and Mg15Fe with LiBH4 have been produced by short-time milling under an argon atmosphere. These composites show enhanced reversible hydrogen capacities of 7 wt% (Ni) and 5.5 wt% (Fe) at 573 K in just 300 s. The presence of LiBH4 does not modify the thermodynamic of the composites, but does account for their improved kinetic behavior. As evidence of a new kind of Mg-B interaction, MgNi3B2 is clearly identified after successive hydrogen sorption cycles below 623 K. (C) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.