کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1297515 | 1498403 | 2006 | 4 صفحه PDF | دانلود رایگان |
The layered phases derived from YBaCo4O7 exhibit a relatively low thermal expansion, significant mixed conductivity and attractive electrochemical activity in contact with doped LaGaO3 solid electrolyte. These properties may be of interest for intermediate-temperature SOFC cathodes. Moderate doping of yttrium-barium cobaltite with iron decreases slightly the total conductivity, predominantly p-type electronic, and have no essential effect on the oxygen ion transport and cathodic polarization at 1073 K. However, hexagonal YBaCo4O7, where the average cobalt oxidation state is + 2.25, and its derivatives appear metastable at temperatures below 1050–1100 K. Oxygen uptake at intermediate temperatures in air leads to the phase decomposition, accompanied by increasing conductivity and dramatic volume contraction.
Journal: Solid State Ionics - Volume 177, Issues 19–25, 15 October 2006, Pages 1823–1826