Effect of Thermal Treatment on the Electronic Conductivity Properties of Cobalt Spinel Phases Synthesized by Electro-Oxidation in Ternary Alkaline Electrolyte (KOH, LiOH, NaOH)

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• 作者：Myriam Douin ; Liliane Guerlou-Demourgues ; Michel Mé ; né ; trier ; Emilie Bekaert ; Lionel Goubault ; Patrick Bernard ; Claude Delmas
• 刊名：Chemistry of Materials
• 出版年：2008
• 出版时间：November 11, 2008
• 年：2008
• 卷：20
• 期：21
• 页码：6880-6888
• 全文大小：212K
• 年卷期：v.20,no.21(November 11, 2008)
• ISSN：1520-5002

文摘

A thermal treatment of Co₃O₄ type spinel phases, synthesized by electrooxidation of CoO powder in a mixed alkaline electrolyte (KOH, LiOH, NaOH), is shown to have an important influence on the electronic conductivity properties of the materials. The initial spinel phase contains hydrogen, lithium, cobalt vacancies, and especially Co⁴⁺ ions within the structure, leading to an electronic conductivity significantly larger than that of stoichiometric Co₃O₄. The thermal treatment, followed by in situ X-ray diffraction, TGA-MS and electronic conductivity measurements, induces a water release, coupled with an increase of the Co/O atomic ratio and a structural reorganization. The resulting cationic redistribution within the spinel framework entails an increase of the Co⁴⁺ amount in the [Co₂O₄] network and therefore of the electronic conductivity (by 3 orders of magnitude).