Enhanced hydrogen sorption kinetics of Mg sub(50)Ni-LiBH sub(4) composite by CeCl sub(3) addition

• Published in: Journal of power sources Vol. 195; no. 10; pp. 3266 - 3274
• Main Authors: Gennari, F C, Puszkiel, JA
• Format: Journal Article
• Language: English
• Published: 15.05.2010
• ISSN: 0378-7753
• DOI: 10.1016/j.jpowsour.2009.12.006

Mg sub(50)Ni-LiBH sub(4) and Mg sub(50)Ni-LiBH sub(4)-CeCl sub(3) composites have been prepared by short times of ball milling under argon atmosphere. Combination of HP-DSC and volumetric techniques show that Mg sub(50)Ni-LiBH sub(4)-CeCl sub(3) composite not only uptakes hydrogen faster than Mg sub(50)Ni-LiBH sub(4), but also releases hydrogen at a lower temperature (225 degree C). The presence of CeCl sub(3) has a catalytic role, but it does not modify the thermodynamic properties of the composite which corresponds to MgH sub(2). Experimental studies on the hydriding/dehydriding mechanisms demonstrate that LiBH sub(4) and Ni lead to the formation of MgNi sub(3)B sub(2) in both composites. In addition, XRD/DSC analysis and thermodynamic calculations demonstrate that the addition of CeCl sub(3) accounts for the enhancement of the hydrogen absorption/desorption kinetics through the interaction with LiBH sub(4). The in situ formation and subsequent decomposition of Ce(BH sub(4)) sub(3) provides a uniform distribution of nanosize CeB sub(4) compound, which plays an important role in improving the kinetic properties of MgH sub(2).