Multiple physics-based investigation of additives and thin film coatings applied to cathode and anode surfaces in hydrogen-fuelled solid oxide fuel cells

In this thesis, hydrogen-fuelled solid oxide fuel cells (SOFCs) were analyzed using a multiphysics modeling approach with the COMSOL Multiphysics software. COMSOL Multiphysics was chosen for the system analysis due to its ability to simultaneously simulate multiple physical phenomena, including electrochemical reactions, heat transfer, mechanical stresses, and fluid dynamics. Based on a literature review, Ni-YSZ was selected as the anode material, LSM as the cathode, 8YSZ as the electrolyte, and Inconel 625 for the flow channels. In the first phase of the study, analyses were conducted at 800 °C, 900 °C, and 1000 °C to determine the optimum operating temperature. It was found that 900 °C provided the most balanced performance. At this temperature, a maximum current density of approximately 22,623 A/m² at 0 V and a maximum power density of 5536 W/m² at 0.5 V were achieved. In the second phase, the effects of platinum (Pt) and palladium (Pd) thin film coatings on system performance were investigated. The thin film coatings significantly improved mechanical, thermal, and electrical performance, with Pt coatings offering higher energy efficiency compared to Pd. In the final phase, molybdenum (Mo) and tungsten (W) dopings were applied to the Pt-coated structures, and comparative performance analyses were carried out. Mo doping provided balanced energy distribution and reduced losses, whereas W doping enhanced current density and reaction management efficiency. Overall, the Pt-coated SOFC structure with Mo doping demonstrated the highest efficiency, minimized energy loss, and achieved balanced mechanical stability, making it the most suitable system configuration.