Comparative analysis of the hydriding kinetics of LaNi sub(5, La) sub(0).8Nd sub(0.2Ni) sub(5) and La sub(0.7Ce) sub(0).3Ni sub(5 compounds)

In two-phase domains, the plateau pressure of hydride forming materials (such as intermetallic compounds or IMCs) depends markedly on the operating temperature (Van't Hoff relationships). Therefore, for practical applications, it is necessary to select hydrogen storage materials by considering...

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Bibliographic Details
Published in:International journal of hydrogen energy 2011-03, Vol.36 (6), p.4178-4184
Main Authors: Ngameni, R, Mbemba, N, Grigoriev, SA, Millet, P
Format: Article
Language:English
Subjects:
Alloy plating
Alloying
Asymptotic properties
Diffusion
Diffusion rate
Hydrides
Hydrogen storage
Operating temperature
Storage tanks
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Summary:In two-phase domains, the plateau pressure of hydride forming materials (such as intermetallic compounds or IMCs) depends markedly on the operating temperature (Van't Hoff relationships). Therefore, for practical applications, it is necessary to select hydrogen storage materials by considering the thermal environment of the hydride tank. The thermodynamic properties (absorption and desorption pressure plateaux) of IMCs can be adjusted to some extend by chemical alloying with foreign metals and substitution on different crystallographic sites. In this paper, we report on the hydriding kinetics of substituted AB sub(5 compounds. Isotherms have been measured at different temperatures on La) sub(x)Nd sub(1-xNi) sub(5) (x [asymptotic to] 0.2) and La sub(xCe) sub(1)-xNi sub(5 (x [asymptotic to] 0.3) compounds. Pneumato-chemical impedance spectroscopy has been used to analyze the hydriding kinetics and to determine microscopic rate parameters associated with surface dissociation of molecular hydrogen, diffusion-controlled transport of atomic hydrogen to bulk regions and hydride formation. Results have been compared to those measured on LaNi) sub(5) and the interest of using such substituted compounds for application in auxiliary power units is discussed.
ISSN:0360-3199
DOI:10.1016/j.ijhydene.2010.06.107