Influence of the alkaline electrolyte on the behavior of Na0.6CoO2 used as conductive additive in positive electrode of Ni-MH cells

The influence of the electrolyte alkaline ions, potassium, lithium, and sodium, on the efficiency of the Na0.6CoO2 phase, as a conductive additive in the positive nickel oxide electrode, is analyzed in the present paper. Aging tests of the Na0.6CoO2 phase and of the gamma-Co phases, deriving from it...

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Bibliographic Details
Published in:Journal of the Electrochemical Society 2008, Vol.155 (12), p.A945-A951
Main Authors: Douin, Myriam, Guerlou-Demourgues, Liliane, Goubault, Lionel, Bernard, Patrick, Delmas, Claude
Format: Article
Language:English
Subjects:
Chemical Sciences
Material chemistry
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Summary:The influence of the electrolyte alkaline ions, potassium, lithium, and sodium, on the efficiency of the Na0.6CoO2 phase, as a conductive additive in the positive nickel oxide electrode, is analyzed in the present paper. Aging tests of the Na0.6CoO2 phase and of the gamma-Co phases, deriving from it, in the three electrolyte components, KOH, NaOH, and LiOH, have shown the presence of topotactic exchange/(de)intercalation reactions of the alkaline ions, occurring within the materials. Electrochemical tests, performed in the various electrolytes, underline an unfavorable effect of lithium ions. The formation of a semiconductive LixCoO2 phase has been identified as responsible for the loss of efficiency of the conductive material, when lithium ions are present in the electrolyte.
ISSN:0013-4651
1945-7111
DOI:10.1149/1.2988095