A La0.9Sr0.1Ga0.8Mg0.2O3 (LSGM)-based honeycomb-type solid oxide fuel cell (SOFC) with a 0.5 mm thick electrolyte wall was successfully fabricated and operated. This cell shows a much higher volumetric power density than a ZrO2-based cell in the temperature range from 973 to 1173 K. Detailed results of internal resistance analysis suggest that IR loss is the predominant internal resistance of the cell. Furthermore, improved power density is achieved by decreasing LSGM electrolyte wall thickness. The effective area power densities are about 0.50 and 0.27 W/cm(2) at 1073 and 973 K, respectively, using a 0.5 mm thick electrolyte wall. A 0.5 mm thick 4-wall cell was also successfully fabricated and operated at 1073 K; the estimated volumetric power density of this cell is as high as 600 W/L when five channels are used. (C) 2008 Elsevier B.V. All rights reserved.