Improved thermal cycling durability of a solid oxide fuel cell (SOFC) using a LaGaO3-based electrolyte was studied by inserting a thin Sm0.5Sr0.5CoO3-delta (SSC55) cathode interlayer with a submicron-sized convex. The thin SSC55 interlayer was prepared on a SDC20-LSGM9182 bilayer film by pulsed layer deposition. The resulting maximum power density (MPD) was 1.99 W/cm(2) at 973 K, and the open circuit voltage was close to the theoretical value. In addition, the thermal cycling tolerance was significantly improved. The decrease in MPD was only 4% over three thermal cycles from 973 to 298 K. The MPD of a cell with no SSC55 interlayer decreased significantly. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3494029] All rights reserved.