Studying Low-Humidity Effects in PEFCs Using EIS II: Modeling
2012 (English)In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 159, no 8, F379-F392 p.Article in journal (Refereed) Published
Electrochemical impedance spectroscopy (EIS) and steady-state models have been developed to investigate the influence of water transport on the membrane and electrode performance, with focus on the low-frequency impedance. Models for the membrane, hydrogen anode and oxygen cathode were connected in order to take the influence of water concentration on proton conductivity and hydrogen kinetics into account. At low frequencies, below 1 Hz, a pseudo-inductive loop was predicted, resulting from the overlap of the responses from anode and membrane. The anode response could be coupled to changes in the kinetics and polymer conductivity in the active layer, and the membrane response to changes in conductivity with changing water profile. The low frequency capacitive part was attributed to drying of the anode side of the membrane, while the inductive part was attributed to the rehydration of the membrane with water produced at the cathode. The loop appeared at a frequency proportional to 1/L-2, where L is the membrane thickness. The model was successfully fitted to experimental data at different membrane thicknesses, relative humidities and current densities. The modeled data follow the same trends as experimental data, giving an increase in impedance at dry conditions and with thicker membranes.
Place, publisher, year, edition, pages
2012. Vol. 159, no 8, F379-F392 p.
Other Chemical Engineering
IdentifiersURN: urn:nbn:se:kth:diva-103399DOI: 10.1149/2.006208jesISI: 000308559400057OAI: oai:DiVA.org:kth-103399DiVA: diva2:559964
FunderSwedish Research CouncilStandUp
QC 201210112012-10-112012-10-112016-04-11Bibliographically approved