화학공학소재연구정보센터
Journal of Power Sources, Vol.185, No.2, 641-648, 2008
Characterization and optimization of La0.8Sr0.2Sc0.1Mn0.9O3-delta-based composite electrodes for intermediate-temperature solid-oxide fuel cells
Composite electrodes composed of a perovskite-type La0.8Sr0.2Sc0.1Mn0.9O3-delta(LSSM) and a fluorite-type scandium-stabilized zirconia (ScSZ) were prepared and evaluated as potential cathodes for intermediate-temperature solid-oxide fuel cells. Characterization was made by phase reaction, electrochemical impedance spectroscopy, step Current polarization and I-V tests. The phase reaction between LSSM and ScSZ occurred at 1150 degrees C or higher; however, it had a minor effect on the electrode performance. The formation of a composite electrode led to an obvious improvement in both charge transfer and surface-related processes. With the increase of ScSZ content, the rate-limiting step of oxygen reduction reaction steadily changed from mainly a surface diffusion process to an electron transfer process. The optimal ScSZ content and sintering temperature of the electrode layer were found to be 20 wt.% and 1100-1150 degrees C, respectively. Under optimal conditions, an anode-supported single cell with LSSM + ScSZ composite cathode showed high power densities of similar to 1211 and 386 MW cm(-2) at 800 and 650 degrees C, respectively. (C) 2008 Elsevier B.V. All rights reserved.