Decrease of PEMFC Performance by SO2 in Air

The effects of SO2 on the performance of proton exchange membrane(PEMFC) were investigated by introduction air containing SO2 into cathode inlet of PEMFC. And the recovery of the cell performance by applying clean air, cycle voltammetry(CV) and high voltage holding following exposure contaminated air was studied. The SO2 concentration range used in the experiments was from 20 ppb to 1.3 ppm. The performance degradation and recovery were measured by constant-current discharging, I-V polarization and electrochemical impedance spectroscopy(EIS). The cell voltage gradually decayed with time and decreased by 17 mV after 200 hours of 20 ppb SO2 injection. The cell performance can be recovered partially by clean air flushing, CV and high voltage holding due to desorption of S from Pt catalyst.