Ball-milling and AlB(2) addition effects on the hydrogen sorption properties of the CaH(2) + MgB(2) system

Among the borohydrides proposed for solid state hydrogen storage, Ca(BH(4))(2) is particularly interesting because of its favourable thermodynamics and relatively cheap price. Composite systems, where other species are present in addition to the borohydride, show some advantages in hydrogen sorption...

Full description

Saved in:
Bibliographic Details
Published in:Journal of alloys and compounds 2011-09, Vol.509, p.S714-S718
Main Authors: Schiavo, B, Girella, A, Agresti, F, Capurso, G, Milanese, C
Format: Article
Language:English
Subjects:
Borides
Borohydrides
Hydrogen storage
Magnesium
Magnesium compounds
Sorption
Spectra
Storage capacity
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Among the borohydrides proposed for solid state hydrogen storage, Ca(BH(4))(2) is particularly interesting because of its favourable thermodynamics and relatively cheap price. Composite systems, where other species are present in addition to the borohydride, show some advantages in hydrogen sorption properties with respect to the borohydrides alone, despite a reduction of the theoretical storage capacity. We have investigated the milling time influence on the sorption properties of the CaH(2) + MgB(2) system from which Ca(BH(4))(2) and MgH(2) can be synthesized by hydrogen absorption process. Manometric and calorimetric measurements showed better kinetics for long time milled samples. We found that the total substitution of MgB(2) with AlB(2) in the starting material can improve the sorption properties significantly, while the co-existence of both magnesium and aluminum borides in the starting mixture did not cause any improvement. Rietveld refinements of the X-ray powder diffraction spectra were used to confirm the hypothesized reactions.
ISSN:0925-8388
DOI:10.1016/j.jallcom.2010.11.045