title: Al3Li4(BH4)13: a complex double-cation borohydride with a new structure.
abstract: The new double-cation Al-Li-borohydride is an attractive candidate material for hydrogen storage due to a very low hydrogen desorption temperature (approximately 70 degrees C) combined with a high hydrogen density (17.2 wt%). It was synthesised by high-energy ball milling of AlCl(3) and LiBH(4). The structure of the compound was determined from image-plate synchrotron powder diffraction supported by DFT calculations. The material shows a unique 3D framework structure within the borohydrides (space group=P-43n, a=11.3640(3) A). The unexpected composition Al(3)Li(4)(BH(4))(13) can be rationalized on the basis of a complex cation [(BH(4))Li(4)](3+) and a complex anion [Al(BH(4))(4)](-). The refinements from synchrotron powder diffraction of different samples revealed the presence of limited amounts of chloride ions replacing the borohydride on one site. In situ Raman spectroscopy, differential scanning calorimetry (DSC), thermogravimetry (TG) and thermal desorption measurements were used to study the decomposition pathway of the compound. Al-Li-borohydride decomposes at approximately 70 degrees C, forming LiBH(4). The high mass loss of about 20 % during the decomposition indicates the release of not only hydrogen but also diborane.
authors.affiliation: IFW Dresden, Dept. 21, Helmholtzstrasse 20, 01069 Dresden, Germany. I.Lindemann@ifw-dresden.de
authors.forename: Inge
authors.initials: I
authors.lastname: Lindemann
authors.forename: Roger
authors.initials: R
authors.lastname: Domènech Ferrer
authors.forename: Lothar
authors.initials: L
authors.lastname: Dunsch
authors.forename: Yaroslav
authors.initials: Y
authors.lastname: Filinchuk
authors.forename: Radovan
authors.initials: R
authors.lastname: Cerný
authors.forename: Hans
authors.initials: H
authors.lastname: Hagemann
authors.forename: Vincenza
authors.initials: V
authors.lastname: D'Anna
authors.forename: Latévi Max
authors.initials: LM
authors.lastname: Lawson Daku
authors.forename: Ludwig
authors.initials: L
authors.lastname: Schultz
authors.forename: Oliver
authors.initials: O
authors.lastname: Gutfleisch