La0.8Sr0.2FeO3−δ as Fuel Electrode for Solid Oxide Reversible Cells Using LaGaO3-Based Oxide Electrolyte

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• 作者：Kohei Hosoi ; Hidehisa Hagiwara ; Shintaro Ida ; Tatsumi Ishihara
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：July 28, 2016
• 年：2016
• 卷：120
• 期：29
• 页码：16110-16117
• 全文大小：542K
• 年卷期：0
• ISSN：1932-7455

文摘

Activity of La_0.8Sr_0.2FeO₃ (LSF) to the fuel electrode reaction in solid oxide reversible cells (SORCs) was investigated by using La_0.9Sr_0.1Ga_0.8Mg_0.2O₃ (LSGM) and Ba_0.6La_0.4CoO₃ (BLC) as electrolyte and air electrode, respectively. In electrolysis mode (SOEC), the LSF electrode exhibited small overpotential under the atmosphere without H₂ cofeeding; the current densities reached −1.42, −0.92, and −0.36 A/cm² at 1.4 V at 900, 800, and 700 °C, respectively, and the H₂ formation rate is well agreed with that estimated by Faraday’s law. On the other hand, in the SOEC–SOFC reversible mode with the gas composition of 20% steam/20%H₂/60%Ar, the maximum power densities of 0.42, 0.28, and 0.11 W/cm² were achieved at 900, 800, and 700 °C, respectively. In addition, the cyclic reversible operation was also investigated at 800 °C, and it was found that the cell showed high stability over 30 cycles. DC polarization measurement suggests that the exchange current density of LSF is 14 mA/cm² at 700 °C, which is almost the same as that of Ni-YSZ reported. X-ray diffraction (XRD) measurement and scanning electron microscopy (SEM) observation after the reversible measurement suggest that LSF is highly stable under SOEC–SOFC cyclic operation conditions. Therefore, LSF is promising as the fuel electrode for SORCs, although the conductivity is not sufficiently high as an electrode.