Nengyou Jia

Transient Analysis of Hydrogen Sulfide Contamination on the Performance of a PEM Fuel Cell

A transient kinetic model for the anode catalyst layer of a proton exchange membrane (PEM) fuel cell is proposed to describe the performance loss introduced by the hydrogen sulfide contaminant. Reaction rates are considered as functions of cell current density and contamination level and are estimated based on the available experimental data. It is found that at a constant cell current density the surface coverage of Pt-S increases faster with time and the anode overpotential rises sharply when increasing the contamination level from 1 to 10 ppm, leading to a faster and more severe cell performance degradation. At a constant contamination level, the surface coverage of Pt-S also increases faster with time when increasing the cell current density from 0.1 to 1.0 A cm -2 , resulting in faster and more severe cell performance degradation. Simulation shows that the contaminant surface coverage at steady state is governed by current density. With the same contaminant concentration, to maintain a higher current density output, a significant decrease of steady-state contaminant coverage is required, while at a lower current density, steady-state contaminants coverage increases significantly.

Durability of PEMFC Cathodes Exposed to Toluene-contaminated Air

The effects of toluene contamination on the performance of polymer electrolyte membrane fuel cells (PEMFCs) were studied. The severity of the contamination effect increased with increases in the current density, the toluene concentration and air stoichiometry, but decreased with an increase in the back pressure. The effect of toluene contamination on current dynamic operation was also studied by cycling the current density from 0.0 to 0.2, and then to 1.0 A cm -2 at the presence of toluene. The degradation of the fuel cell performance during the current dynamic operation was accelerated by the presence of toluene.