A gadolinia-doped ceria (GDC) capping layer was fabricated on a metal Pt cathode via a sputtering technique to enhance the thermal stability and oxygen-reduction reaction (ORR) kinetics. By varying the thickness of the GDC thin film on the Pt cathode, we fabricated thermally durable low-temperature solid oxide fuel cells (LT-SOFCs) on porous anodized aluminum oxide (AAO) substrates while securing very high performance. The GDC protective layers subsequently mitigated the agglomeration of the Pt morphology by hindering the coarsening of metal grains, and enhanced the cathodic kinetics as a result of the increased TPB density at the Pt-electrolyte interface. Enhanced performance of fuel cells and thermo-stable behavior with the GDC capping layer were demonstrated by employing transmission electron microscopy (TEM) and electrochemical analysis. An enhanced peak power density of 258 mW/cm(2) was obtained with a degradation of 56.4% of the Pt cathode over 25 hours of operation at 450 degrees C. (c) 2017 The Electrochemical Society. All rights reserved.