Electrical, Chemical, and Electrochemical Properties of Double Perovskite Oxides Sr2Mg1鈥?i>xNixMoO6鈭捨?/sub> as Anode Materials for Solid Oxide Fuel Cel

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• 作者：Zhixiang Xie ; Hailei Zhao ; Zhihong Du ; Ting Chen ; Ning Chen
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：August 21, 2014
• 年：2014
• 卷：118
• 期：33
• 页码：18853-18860
• 全文大小：525K
• ISSN：1932-7455

文摘

The suitability of double perovskite oxides of composition Sr₂Mg_1鈥?i>xNi_xMoO_{6鈭捨?/sub> (SMNM, x = 0鈥?.9) as anode materials for solid oxide fuel cells (SOFCs) was evaluated. Single double perovskite structures could be obtained up to x = 0.9 in syntheses at ambient atmosphere. However, after reduction at 800 掳C, trace amounts of impurities were detected in the sample with x = 0.9, suggesting that the upper limit for the Ni content (x) in SMNM is less than 0.9 under SOFC operating conditions. The electrical conductivity of SMNM increases with increasing Ni content because of the increase in the concentration of electronic defects, [MoMo⁶⁺⁵⁺鈥瞉, and the decreased band gap energy, as revealed by first-principles calculations. The substitution of Ni can facilitate the charge-transfer process of the electrode reaction, decrease the polarization resistance, and thus increase the power density of a single cell. X-ray photoelectron spectroscopy and temperature-programmed reduction measurements were used to explain the reason for the performance improvement. SMNM showed good chemical compatibility with Ce0.8Sm0.2O2鈭捨?/sub> (SDC) but a slight reactivity with the electrolyte La0.8Sr0.2Ga0.83Mg0.17O3鈭捨?/sub> (LSGM) at 1300 掳C. The use of an SDC buffer layer could avoid the interface reaction between the SMNM anode and the LSGM electrolyte, resulting in better cell performance. The Sr2Mg0.3Ni0.7MoO6鈭捨?/sub> electrode exhibited a maximal power density of 160 mW cm^鈥? at 800 掳C with an electrolyte (LSGM, 400 渭m)-supported cell configuration.}