Obtaining a catalyst with high activity and thermal stability is essential for high-performance energy conversion devices operating at an elevated temperature. Herein, the design and fabrication of a heterogeneous catalyst with an ultrathin CeO2 overlayer via atomic layer deposition (ALD) on Pt electrodes for low-temperature solid oxide fuel cells (LT-SOFCs) is reported. The cell with a CeO2-overcoated (five ALD cycles) Pt cathode shows lower activation resistance by 50% after a 10 h operation and higher thermal stability by a factor of 2 compared with the cell with a Pt-only cathode, which is known to be the best single catalyst at 450 °C. Eventually, a thin-film SOFC with a highly active and stable CeO2-overcoated cathode based on an anodized aluminum oxide (AAO) substrate demonstrates a high peak power density of 800 mW cm–2 at 500 °C, which is the highest performance ever reported for an AAO-based SOFC at this temperature.

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Agglomeration of the metal electrode decreases the performance of low-temperature solid oxide fuel cells (LT-SOFC) during operation at elevated temperatures. Here, we report a Pt electrode/ridge-valley nanostructured samaria-doped ceria (SDC) layer interface with extended lifetime. LT-SOFCs with RF-sputtered SDC interlayers with thicknesses in the range 65-260 nm show a >20 times lower degradation of performance as compared to cells without interlayer when operated at 450 C (1.8% h À1 vs. 45% h À1 ). Micromorphological analysis reveals that the coarsening of the Pt electrode is significantly suppressed by the presence of the nanostructured SDC interlayer, possibly due to a stronger bonding between this layer and the Pt grains.