Facilitating de/hydrogenation by long-period stacking ordered structure in Mg based alloys

We propose a simple strategy to effectively improve the hydrogenation and dehydrogenation kinetics of Mg based hydrogen storage alloys. We designed and prepared an Mg91.9Ni4.3Y3.8 alloy consisting of a large quantity of long-period stacking ordered (LPSO) phases. A type of highly dispersed multiphas...

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Bibliographic Details
Published in:International journal of hydrogen energy 2013-08, Vol.38 (25), p.10438-10445
Main Authors: Liu, J.W., Zou, C.C., Wang, H., Ouyang, L.Z., Zhu, M.
Format: Article
Language:English
Subjects:
Alloys
Alternative fuels. Production and utilization
Applied sciences
Dehydrogenation
Dispersion
Energy
Exact sciences and technology
Fuels
Hydrogen
Hydrogen storage
Hydrogen storage material
Hydrogenation
Kinetics
Long-period stacking ordered structure
Mg–Ni–Y
Nanostructure
Phases
Stacking
TEM
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Summary:We propose a simple strategy to effectively improve the hydrogenation and dehydrogenation kinetics of Mg based hydrogen storage alloys. We designed and prepared an Mg91.9Ni4.3Y3.8 alloy consisting of a large quantity of long-period stacking ordered (LPSO) phases. A type of highly dispersed multiphase nanostructure, which can markedly promote the de/hydrogenation kinetics, has been obtained utilizing the decomposition of LPSO phases at first a few of hydrogenation reactions. The fine structures of LPSO phases and the microstructural evolutions of the alloy during hydrogenation and dehydrogenation reactions were in detail characterized by means of transmission electron microscopy (TEM). The LPSO phases transformed to MgH2, Mg2NiH4, and YH3 after the first hydrogenation. The highly dispersed nanostructure at macro and micro (nano) scale range remains even after several de/hydrogenation cycles. The alloy shows excellent hydrogen storage properties and its reversible hydrogen absorption/desorption capacities are about 5.8 wt% at 300 °C. Particularly, the alloy exhibits very fast dehydrogenation kinetics. The dehydrogenated sample can release approximately 5 wt% hydrogen at 300 °C within 200 s and 5.5 wt% within 600 s. We elucidate the structural mechanism of the alloy with outstanding hydrogen storage performance. [Display omitted] •Highly dispersed multiphase nanostructure was obtained via decomposition of LPSO in Mg91.9Ni4.3Y3.8 alloy.•The alloy shows excellent hydrogen storage capacity and very fast de/hydrogenation kinetics.•The structural mechanism of the alloy during de/hydrogenation was revealed.
ISSN:0360-3199
1879-3487
DOI:10.1016/j.ijhydene.2013.05.149