Connecting microstructural coarsening processes to electrochemical performance in solid oxide fuel cells: An integrated modeling approach

• Published in: Journal of power sources 2014-03, Vol.250, p.319-331
• Main Authors: Abdeljawad, Fadi, Völker, Benjamin, Davis, Ryan, McMeeking, Robert M., Haataja, Mikko
• Format: Article
• Language: English
• Subjects: Anodes; Applied sciences; Coarsening; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical analysis; Electrochemical conversion: primary and secondary batteries, fuel cells; Electrochemical performance; Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Fuel cells; Microstructure; Ni coarsening; Nickel; Particle size; Phase field; Solid oxide fuel cell (SOFC); Solid oxide fuel cells; Topological evolution; Yttria stabilized zirconia
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2013.10.121

In solid oxide fuel cells (SOFCs), Ni coarsening in porous anodes that are comprised of Ni and yttria stabilized zirconia (YSZ) leads to changes in several microstructural attributes, which affect the electrochemical performance. Herein we present an integrated modeling approach, where a dynamic mesoscale phase field model is linked with a stationary macroscale electrochemical cell level model in order to assess the role of Ni coarsening on the performance of SOFCs. The phase field model is capable of capturing the morphological evolution of Ni and accounting for its polycrystalline nature, while the electrochemical model encompasses the entire set of processes of gas transport, electronic and ionic conduction as well as the electrochemical reactions. Microstructural features are extracted from the phase field model as anode systems evolve over time and employed as effective properties in the electrochemical model. Simulation results highlight the importance of Ni and YSZ particle size and ratio on both the microstructural stability and electrochemical performance of SOFCs. In particular, it is shown that, for the classes of microstructures employed in this work, coarsening of Ni particles can either improve or diminish the maximum power density relative to the as-sintered ones, depending on the initial particle size. •Integrated model: a phase-field model and an electrochemical cell one are linked.•Using the integrated model, we study the role of Ni coarsening on SOFC performance.•Simple scaling laws describe the evolution of key microstructural features.•Ni particle size strongly affects morphological evolution in Ni–YSZ SOFC anodes.•Integrated approach facilitates identification of parameters associated with stable microstructures and/or optimal performance.