Abstract
Solid oxide fuel cells (SOFCs) are one of the most promising types of fuel cells, which convert the chemical energy of fuel into electricity and operate at elevated temperatures (conventionally > 800°C). Wide deployment of SOFCs has been significantly hampered by high costs, lengthy startup, thermal stresses, and unintended chemical reactions between components. Lowering the working temperature to a more moderate range (600–800 °C) is a key to avoiding these issues, enabling this technology's long-term operation and commercial viability. However, lowering the operating temperature results in a significant sacrifice in both ionic conductivity and catalytic activity, especially the kinetics of oxygen reduction reaction (ORR) occurring at the cathode.

This study focuses on improving the performance of (La,Sr)(Co,Fe)O3-δ (LSCF)-based SOFC cathodes by introducing a nanoscale interlayer between the cathode and electrolyte using the spin-coating or atomic layer deposition (ALD) technique. In the first study, the effect of different layers (200-800 nm) of LSCF, gadolinia-doped ceria (GDC), and LSCF-GDC composites inserted at the LSCF-based cathodic interface via spin-coating were studied. Samples that are spin-coated with LSCF 4 times showed the best performance. The result is ascribed to the mixed ionic and electronic conducting property of LSCF, which effectively enlarges the active ORR sites. In the second study, the interfacial layer effect was examined by using ALD. Ten layers of ceria ALD rendered the best performance. In addition, the dependencies of electrode polarization resistance on the number of deposited layers, temperature, and oxygen partial pressure were presented to understand cells' behavior and limiting factors.

Biography
Orbel Barkhordarian is an M.S. candidate in the Department of Mechanical Engineering at the University of California, Merced. His work is focused on the development of durable and high-performance solid oxide fuel cells using atomic/nano-scale engineering methods. He received his B.Sc. degree in mechanical engineering and M.S. in energy systems engineering from K.N. Toosi University of Technology, Iran.