Ag-Ce_0.9Gd_0.1O_2-δ-Based Nanocomposite Thin Film Air Electrodes for Low-Temperature Solid Oxide Cells

Understanding and controlling the interfaces between different materials is crucial for developing solid oxide cells (SOCs) with both high performance and durability for low-temperature operation (<700 °C). Current research focuses on evaluating microstructural designs and composite material interactions to optimize SOC performance. Nanocomposite heterostructures exhibit unique properties at the interfaces, which are achieved through precise control of the composition, thickness, and surface chemistry. In this investigation, our goal was to develop nanocomposite films using a combination of a metal and a metal oxide. Specifically, we successfully fabricated Ag-Ce_0.9Gd_0.1O_2-δ (Ag-CGO) nanocomposite thin films using pulsed laser deposition (PLD) in a single step. Dense Ag-CGO films with thicknesses of approximately 30 and 300 nm were grown on (100)-oriented yttria-stabilized zirconia (YSZ) substrates. The 300 nm-thick films exhibited an area-specific resistance (ASR) value of 22.6 Ω cm² at 480 °C in a symmetrical cell configuration. This value is comparable to that of a micrometer scale-thick Ag electrode with a coarse porous microstructure. Therefore, Ag-CGO films represent a promising alternative to bulk Ag-based SOC electrodes by significantly reducing noble metal usage. The process described is suitable for integration into thin-film solid oxide fuel cell fabrication processes, as it eliminates the subsequent annealing step required to form a stable and active layer. Overall, this study provides valuable insights into enhancing the performance of metal/metal oxide thin films as SOC electrodes for low-temperature operation. While further investigations are necessary to optimize long-term stability, these films may also prove attractive for alternative catalytic applications operating at lower or ambient temperatures.