Hydrogen and material quality issues for PEM fuel cells

The transportation industry is under mounting pressure to move to more environmentally friendly energy sources. This is primarily because of increased publicity relating to acid rain, increased levels of air pollution, greenhouse gas emissions and fossil fuel depletion. One potential replacement for fossil fuel energy in internal combustion engines is fuel cells. Fuel cells, however, face a problem of declining power generation if contaminants are allowed to enter the fuel cell. The contaminants can enter the fuel cell as impurities in the fuel and oxidant gas streams. Additionally, fuel cell components such as bipolar plates and sealing gaskets have a tendency to evolve impurities which could degrade the performance of the proton exchange membrane fuel cell (PEMFC). This paper will explore the potential effects of contaminants on the performance of a PEMFC. The effect of low levels of carbon monoxide (CO) in the hydrogen (H2) fuel gas will be examined. Additionally, the ability of the fuel cell to recover from CO exposure will be explored. Preliminary guidelines for CO will be presented for hydrogen purity. The potential of metal contaminants to leach from the fuel cell components will also be explored. Data will be presented to understand the nature of the contaminants.