Impedance Spectroscopy Measurements of Ionomer Film Oxygen Transport Resistivity in Operating Low-Pt PEM Fuel Cell.

The work presents a model for local impedance of low-Pt proton exchange membrane fuel cells (PEMFCs), including cathode pore size distribution and O transport along pores and through a thin ionomer film covering Pt/C agglomerates. The model was applied to fit the local impedance spectra of low-Pt fuel cells operated at current densities from 100 to 800 mA cm and recorded by a segmented cell system. Assuming an ionomer film thickness of 10 nm, the fitting returned the product of the dimensionless Henry's constant of oxygen dissolution in ionomer by the oxygen diffusivity in the ionomer ().

Correction: Nafion film transport properties in a low-Pt PEM fuel cell: impedance spectroscopy study.

[This corrects the article DOI: 10.1039/C9RA07794D.].

Nafion film transport properties in a low-Pt PEM fuel cell: impedance spectroscopy study.

Unexpected over-linear transport loss in low-Pt PEM fuel cells has been a subject of numerous studies and discussions in literature. Most of the authors agree that these losses are due to oxygen transport in the Nafion film covering Pt/C agglomerates in the cathode catalyst layer (CCL). We develop a model for PEM fuel cell impedance, which takes into account oxygen transport through the film.