Phase Stability Control of Interstitial Oxide Ion Conductivity in the La1+xSr1−xGa3O7+x/2 Melilite Family

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• 作者：Chris I. Thomas ; Xiaojun Kuang ; Zengqiang Deng ; Hongjun Niu ; John B. Claridge ; Matthew J. Rosseinsky
• 刊名：Chemistry of Materials
• 出版年：2010
• 出版时间：April 27, 2010
• 年：2010
• 卷：22
• 期：8
• 页码：2510-2516
• 全文大小：907K
• 年卷期：v.22,no.8(April 27, 2010)
• ISSN：1520-5002

文摘

The two-dimensional polyhedral anion network melilites La_1+xSr_1−xGa₃O_7+0.5x exhibit interstitial oxide ion conductivity. The solid solution is shown to extend to x = 0.64, and the variation of the conductivity with x is investigated. At high temperatures, all of these compounds adopt the typical tetragonal melilite structure. When x > 0.6, cooling below 600 °C results in a reversible phase transition to an orthorhombic structure which reduces the ionic conductivity. Quenching experiments have shown the tetragonal structure has a higher conductivity compared to the orthorhombic structure of the same composition. Short-range order effects associated with this transition exercise an important influence on the composition- and temperature-dependence of the conductivity.