Performance of anode-supported solid oxide fuel cell with La sub(0.85)Sr sub(0.15 )MnO sub(3) cathode modified by sol-gel coating technique

• Published in: Journal of power sources 2002-04, Vol.106 (1-2), p.160-166
• Main Authors: Yoon, Sung Pil, Han, Jonghee, Nam, Suk Woo, Lim, Tae-Hoon, Oh, In-Hwan, Hong, Seong-Ahn, Yoo, Young-Sung, Lim, Hee Chun
• Format: Article
• Language: English
• ISSN: 0378-7753

Yttria-stabilized zirconia (8mol%; YSZ) or samaria-doped ceria (Sm sub(0.2)Ce sub(0.8)O sub(2); SDC)-modified La sub(0.85)Sr sub(0.15)MnO sub(3) (LSM) composite cathodes were fabricated by formation of an YSZ or SDC film at the triple-phase boundary (TPB) of LSM/YSZ/gas. The YSZ film greatly enlarged the number of electrochemical reaction sites (ERSs) by increasing the TPB. The composite cathode was formed on thin YSZ electrolyte (about 30 mu m thickness) supported on an anode and then I-V characterization and ac impedance analyses were performed at temperatures between 700 and 800 degree C. As a result of the impedance analysis on the cell at 800 degree C, with humidified hydrogen as the fuel and air as the oxidant, the element R sub(1) around the frequency of 1000 Hz is identified as the anode polarization, R sub(2 ) around the frequency of 100 Hz is identified as the cathode polarization and R sub(3) below the frequency of 10 Hz is the resistance of gas phase diffusion through the anode. The maximum power densities of the cell modified by the SDC sol-gel coating were about 0.53W/cm super(2) at 750 degree C and about 0.19W/cm super(2) at 650 degree C. The result implied that deposition of SDC in the pore surface of the cathode increased the area of the TPB, resulting in a decrease of cathode polarization and improved cell performance. copyright 2002 Elsevier Science B.V. All rights reserved.