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MM: Fachverband Metall- und Materialphysik

MM 17: Postersession I

MM 17.19: Poster

Monday, March 16, 2015, 18:00–20:00, Poster E

Thermally induced hydrogen desorption of metal-borohydrides — Christoph J. Sahle¹, Simon Kujawski², Arndt Remhof³, Yigang Yan³, Nick Stadie³, Kolja Mende², Ali Al-Zein¹, Simo Huotari⁴, Metin Tolan², and •Christian Sternemann² — ¹European Synchrotron Radiation Facility, Grenoble, France — ²Fakultät Physik / DELTA, Technische Universität Dortmund, Dortmund, Germany — ³Empa, Hydrogen and Energy, Dübendorf, Switzerland — ⁴Department of Physics, University of Helsinki, Helsinki, Finland

Complex lightweight hydrides are candidates for efficient reversible hydrogen storage. During dehydrogenation the hydrides decompose into both crystalline and amorphous phases where latter are often difficult to detect. We use x-ray Raman scattering, a bulk sensitive probe of soft x-ray absorption edges, to measure e.g. boron K- and magnesium L-edges both ex-situ and in-situ during decomposition. To clarify possible decomposition pathways, spectra of reference samples are employed to fingerprint intermediate phases via principal component analysis. Results for magnesium and calcium borohydrides will be discussed with focus on the formation of closo-borane species, which could act as a boron sink and hinder cycling.