Permeability of Gases in the Anode of an Anode Supported SOFC

• Published in: ECS transactions Vol. 68; no. 1; pp. 1185 - 1192
• Main Authors: Geagea, Maya, Genov, Ivaylo, Stoynov, Zdravko, Vladikova, Daria, Chesnaud, Anthony, Thorel, Alain
• Format: Journal Article
• Language: English
• Published: 2015
• ISSN: 1938-5862; 1938-6737
• DOI: 10.1149/06801.1185ecst

In the high current density regime, the performance of SOFCs is limited by concentration overpotentials when the demand for reactants exceeds the capacity of the porous cermet anode to supply them by gas diffusion mechanisms, and when the rate at which water is produced exceeds the ability of the anode to evacuate water. A compromise should be found between maintaining a high level of activation in the anode, which means a high density of Triple Phase Boundaries (TPB) usually associated with small grains size and small pores, and high gas permeability generally associated with large interconnected pores. The present work aims at determining experimentally the gas permeability of the anode as a function of the percolation, tortuosity and volume fraction of the pores. Anodes with varying porosity ensured by different quantities of pore former were obtained by cold pressing and sintering. SEM image analysis, mercury intrusion porosimetry and permeability measurements for different gases were performed. However, non-linearity as a function of the gases molecular weight is observed.