Comparison of the Sulfur Poisoning of PBI and Nafion PEMFC Cathodes

The poisoning effect of H(2)S and SO(2) in air is compared for phosphoric-acid-doped polybenzimidazole (PBI) membrane and perfluorosulfonic acid (Nafion) proton exchange membrane fuel cells (PEMFCs). The cathodes of PBI PEMFCs are about 70 times more resistant to 1 ppm of H(2)S or SO(2) than the Nafion PEMFCs. The PBI PEMFCs only lose < 2% in cell performance when exposed to 1 ppm of H(2)S or SO(2) and have 5.2 and 7.1% losses with 5 and 10 ppm H(2)S over 24 h, respectively. Purging the poisoned PBI cells with neat air leads to complete performance recovery.