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Title: Microstructure and electrochemical hydrogenation/dehydrogenation performance of melt-spun La-doped Mg{sub 2}Ni alloys

This work focuses on microstructure and electrochemical hydrogen storage properties of La-doped Mg{sub 2}Ni alloys. The alloys with nominal compositions of Mg{sub 2}Ni{sub 1−x}La{sub x} (x = 0, 0.1, 0.3, 0.5) were prepared via metallurgical smelting and melt-spun on a rotating copper wheel. The scanning electron microscope, X-ray diffraction, differential scanning calorimetry and transition electron microscope, galvanostatic charging/discharging and other electrochemical measurements were employed to investigate. The results show that the increasing of La content and melt-spinning speed favors the formation of Mg–Ni–La amorphous/nanocrystalline alloys. It is found that the melt-spun ribbons display increased discharge capacities and superior cycle stabilities compared to the as-cast alloys with and without La. The potentiodynamic polarization results indicate that melt-spun La-doped Mg{sub 2}Ni ribbons possess more positive corrosion potential E{sub corr} and exhibit relatively high corrosion resistance against the alkaline solution. The mechanism for electrochemical hydrogenation/dehydrogenation has been proposed based on the effect of microstructures on the mass/charge transfer process for electrode electrochemical reaction. - Highlights: • Nanocrystalline/amorphous Mg–Ni–La alloys are obtained by melt-spinning. • Microstructures of as-cast and rapid quenched Mg{sub 2}Ni{sub 1−x}La{sub x} alloys are investigated. • Electrochemical hydrogenation properties of experimental alloys are characterized. • Electrochemical hydrogen absorption/desorption mechanism is proposed.
Authors:
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Publication Date:
OSTI Identifier:
22476132
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Characterization; Journal Volume: 106; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ABSORPTION; CORROSION; CORROSION RESISTANCE; CRYSTALS; DEHYDROGENATION; DESORPTION; DOPED MATERIALS; ELECTROCHEMISTRY; ELECTRON MICROSCOPES; HYDROGEN STORAGE; HYDROGENATION; LANTHANUM ADDITIONS; MAGNESIUM ALLOY-AZ31B; MASS; MICROSTRUCTURE; NANOSTRUCTURES; NICKEL ALLOYS; POLARIZATION; SCANNING ELECTRON MICROSCOPY; X-RAY DIFFRACTION