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AKE: Arbeitskreis Energie
AKE 5: Mobilität
AKE 5.3: Talk
Monday, March 14, 2011, 17:30–17:45, MENSA Dül
New double-cation borohydrides — •Inge Lindemann1, Roger Domènech Ferrer1, Yaroslav Filinchuk2, Hans Hagemann3, Radovan Černý3, Ludwig Schultz1, and Oliver Gutfleisch1 — 1IFW Dresden, Institute for Metallic Materials, P.O. Box 270016, 01171 Dresden, Germany — 2Swiss-Norwegian Beam Lines at ESRF, BP-220, 38043 Grenoble, France — 3Department of Physical Chemistry and Crystallography, University of Geneva, 1211 Geneva, Switzerland
Complex hydrides are under consideration for on-board hydrogen storage due to their high hydrogen density. However, up to now conventional borohydrides are either too stable or unstable for applications as in PEM fuel cells (60-120°C). Recently, double-cation borohydride systems have attracted great interest. The desorption temperature of the borohydrides decreases with increasing electronegativity of the cation. Consequentely, it is possible to tailor a feasible on-board hydrogen storage material by the combination of appropriate cations. The stability was found to be intermediate between the single-cation borohydride systems. Two combinations were sucessfully synthesised by metathesis reaction via high energy ball milling. Al-Li-borohydride shows desorption at about 70°C combined with a very high hydrogen density (17.2 wt.%) and the Na-Al-borohydride (14.2 wt.%) decomposes around 90°C. Both desorption temperatures are in the target range for applications. The decomposition pathways were observed by in-situ-Raman spectroscopy, DSC (Differential Scanning Calorimetry), TG (Thermogravimetry) and thermal desorption measurements.