Electrochemical Properties and Dissolution Mechanism of A2Ni7 Hydrides (A=Y, Gd, La–Sm) - Laboratoire Interfaces et Systèmes Electrochimiques Accéder directement au contenu
Article Dans Une Revue ChemElectroChem Année : 2015

Electrochemical Properties and Dissolution Mechanism of A2Ni7 Hydrides (A=Y, Gd, La–Sm)

Résumé

The electrochemical behavior of hydride-forming A2B7 alloys (Y2Ni7, LaSmNi7, and Gd2Ni7) is investigated in KOH solution. The evolution of the material performance is shown to strongly depend on the A elements. Electrochemical impedance spectroscopy (EIS), SEM observations, XRD, and Raman spectroscopy showed that Y2Ni7 is mainly sensitive to calendar corrosion and decrepitation, whereas LaSmNi7 and Gd2Ni7 are sensitive to the concomitant effect of both cycling and calendar corrosion. It is also shown that the capacity loss of Gd2Ni7 can be ascribed to amorphization on cycling, which is not the case for Y2Ni7. The formation of both an thin oxide film (a few tens of nanometers thick) at the material surface, measured by EIS, and the dissolution products formed during long-term immersion, analyzed by Raman spectroscopy, is in agreement with the decrease in material activity evaluated by EIS during cycling at different depths of charge.

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Chimie Autre
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Dates et versions

hal-01224847 , version 1 (05-11-2015)

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Beatriz Puga, Suzanne Joiret, Vincent Vivier, Véronique Charbonnier, Habiba Guerrouj, et al.. Electrochemical Properties and Dissolution Mechanism of A2Ni7 Hydrides (A=Y, Gd, La–Sm). ChemElectroChem, 2015, 2 (9), pp.1321-1330. ⟨10.1002/celc.201500163⟩. ⟨hal-01224847⟩
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