Influence of gas phase mass transfer limitations on molten carbonate fuel cell cathodes
1997 (English)In: Journal of Applied Electrochemistry, ISSN 0021-891X, E-ISSN 1572-8838, Vol. 27, no 10, 1149-1156 p.Article in journal (Refereed) Published
The purpose of this paper is to elucidate to what extent mass transfer limitations in the gas phase affect the performance of porous molten carbonate fuel cell cathodes. Experimental data from porous nickel oxide cathodes and calculated data are presented. One and two-dimensional models for the current collector and electrode region have been used. Shielding effects of the current collector are taken into account. The mass balance in the gas phase is taken into account by using the Stefan-Maxwell equation. For standard gas composition and normal operating current density, the effect of gas-phase diffusion is small. The diffusion in the gaseous phase must be considered at operation at higher current densities. For low oxygen partial pressures, the influence of mass transfer limitations is large, even at low current densities. To eliminate the influence of conversion on polarization curves recorded on laboratory cell units, measurements should always be performed with a five to tenfold stoichiometric excess of oxygen. Two-dimensional calculations show rather large concentration gradients in directions parallel to the current collector. However, the influence on electrode performance is still small, which is explained by the fact that most of the current is produced close to the electrolyte matrix.
Place, publisher, year, edition, pages
1997. Vol. 27, no 10, 1149-1156 p.
IdentifiersURN: urn:nbn:se:kth:diva-12883ISI: A1997XZ13900004OAI: oai:DiVA.org:kth-12883DiVA: diva2:319519
QC 201005182010-05-182010-05-182010-05-18Bibliographically approved