Effects of Electrode Microstructure on Intermediate Temperature Solid Oxide Fuel Cell Performance

Abstract

Abstract In this study, the effects of electrode microstructure and electrolyte parameters on intermediate temperature solid oxide fuel cell (ITSOFC) performance were investigated using a one-dimensional solid oxide fuel cell model from the Pacific Northwest National Laboratory (PNNL). The activation overpotential was investigated through the exchange current density term, which is dependent on the cathode activation energy, the cathode porosity, and the pore size and grain size at the cathode triple phase boundary. The cathode pore size, grain size, and porosity were not integrated in the PNNL model, therefore, an analytical solution for exchange current density from Deng and Petric (2005, “Geometric Modeling of the Triple-Phase Boundary in Solid Oxide Fuel Cells,” J. Power Sources, 140, pp. 297–303) was utilized to optimize their effects on performance. Through parametric evaluation and optimization of the electrode microstructure parameters, the activation overpotential was decreased by 29% and the overall ITSOFC maximum power density was increased by almost 400% from the benchmark PNNL case. The effects and importance of electrode microstructure parameters on ITSOFC performance were defined. Optimization of such parameters will be the key in creating viable ITSOFC systems. Although this was deemed successful for this project, future research should be focused on numerically quantifying and modeling the electrode microstructure in two- and three-dimensions for more accurate results, as the electrode microstructure may be highly multidimensional in nature.