6533b838fe1ef96bd12a473c
RESEARCH PRODUCT
Ball-milling and AlB2 addition effects on the hydrogen sorption properties of the CaH2 + MgB2 system
Alessandro GirellaChiara MilaneseFilippo AgrestiGiovanni CapursoBenedetto Schiavosubject
MagnesiumSorption kineticsMechanical EngineeringInorganic chemistryComposite numberMetals and Alloyschemistry.chemical_elementSorptionBorohydridesHydrogen storageBorohydrideBall-millingHydrogen storagechemistry.chemical_compoundchemistryHydrogen absorptionMechanics of MaterialsAluminiumMaterials ChemistryBall millHydrogen storage; Borohydrides; Ball-milling; Hydrogen absorption; Sorption kineticsPowder diffractiondescription
Abstract 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.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2011-09-01 |