Ca(BH4)(2)-MgF2 Reversible Hydrogen Storage: Reaction Mechanisms and Kinetic Properties

Rapee Gosalawit-Utke, Karina Suarez, Jose M. Bellosta von Colbe, Ulrike Boesenberg, Torben R. Jensen, Yngve Cerenius, Christian Bonatto Minella, Claudio Pistidda, Gagik Barkhordarian, Matthias Schulze, Thomas Klassen, Ruediger Bormann, Martin Dornheim

Research output: Contribution to journalArticlepeer-review

19 Citations (SciVal)

Abstract

A composite of Ca(BH4)(2)-MgF2 is proposed as a reversible hydrogen storage system. The dehydrogenation and rehydrogenation reaction mechanisms are investigated by in situ time-resolved synchrotron radiation powder X-ray diffraction (SR-PXD) and Raman spectroscopy. The formation of an intermediate phase (CaF2-xHx) is observed during rehydrogenation. The hydrogen content of 4.3 wt % is obtained within 4 h during the first dehydrogenation at isothermal and isobaric conditions of 330 degrees C and 0.5 bar H-2, respectively. The cycling efficiency is evaluated by three release and uptake cycles together with absorbed hydrogen content in the range 5.1-5.8 wt % after 2.5 h (T = 330 degrees C and p(H-2) = 130 bar). The kinetic properties on the basis of hydrogen absorption are comparable for all cycles. As compared to pure Ca(BH4)(2) and Ca(BH4)(2)-MgH2 composite, Ca(BH4)(2)-MgF2 composite reveals the kinetic destabilization and the reproducibility of hydrogen storage capacities during cycling, respectively.
Original languageEnglish
Pages (from-to)3762-3768
JournalJournal of Physical Chemistry C
Volume115
Issue number9
DOIs
Publication statusPublished - 2011

Subject classification (UKÄ)

  • Natural Sciences
  • Physical Sciences

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