Physical and Electrochemical Characteristics of Pulsed Laser Deposited La_0.6Sr_0.4CoO_3-Cd-Ce_0.9Gd0.1O _2-Cd Nanocomposites as a Function of the Mixing Ratio

Binary nanocomposite thin films of lanthanum strontium cobaltite and gadolinia-Cdoped ceria (La_0.6Sr_0.4CoO_3-Cd- Ce_0.9Gd_0.1O_2-Cd, LSC-CGDC) were prepared using pulsed laser deposition (PLD) for application as cathodes of low-Ctemperature operating solid oxide fuel cell (LT-CSOFC). The thin films were fabricated under identical deposition conditions, but the LSC:GDC mixing ratio was varied. The PLD-Cprocessed LSC-CGDC nanocomposites exhibit different physical and electrochemical properties than do conventional powder-Cprocessed composite SOFC cathodes. The LSC:GDC mixing ratio not only alters the composition of the LSC-CGDC nanocomposite thin films but also affects their crystallographic orientation and microstructure. The major component of the composite appears to govern the physical properties of the LSC-CGDC nanocomposite thin films. The electrochemical properties measured with AC impedance spectroscopy during the half-Ccell tests reveal that the electrochemical performance of the LSC-CGDC nanocomposite cathode is enhanced as the LSC content in the composite increases, which is in contrast to the behavior of powderprocessed composite cathodes. The present study provides important insight into the design and application of thin-Cfilm-Cprocessed nanocomposite electrodes.