Characteristic thickness for a dense La0.8Sr0.2MnO3 electrode

Dense La0.8Sr0.2MnO3 (LSM) electrodes were patterned by photolithography and fabricated via pulsed-laser deposition on Y2O3-stabalized ZrO2 (YSZ) electrolytes. Impedance analysis shows that the interfacial polarization resistance decreases significantly as electrode thickness drops below a critical value, beyond which the top surface of the LSM becomes active for oxygen reduction. However, when the LSM electrodes become too thin, the in-plane sheet resistance of the LSM starts to limit the utilization of the electrodes along their length. Quantification of the characteristic thickness is important not only to intelligent design of practical mixed-conducting electrodes but also to electrode design for fundamental studies. (c) 2005 The Electrochemical Society.