Cathodic performance of La0.9Sr0.1MnO3 (LSM) electrode on LaGaO3-based electrolyte was examined. The LSM was also mixed with La0.9Sr0.1Ga0.8Mg0.2O3 (LSGM) electrolyte to form a composite electrode. The electrodes with different preparation methods were tested to study the effects of the degree of chemical reaction between electrode and electrolyte, the microstructure, and the mixed-ionic and electronic conductivity on cathodic overpotential. To lower the cathodic overpotential, either reducing the reaction between electrode and electrolyte or enhancing the mixed-ionic and electronic conductivity was more important than controlling the microstructure. (C) 2004 Elsevier B.V. All rights reserved.