Study on Transient Tolerance Concentration of Cathode Ammonia in Proton Exchange Membrane Fuel Cells

Abstract

<div class="section abstract"><div class="htmlview paragraph">The performance and lifetime of proton exchange membrane fuel cells (PEMFC) are affected by impurities in the gas stream. The concentration of ammonia in the air can exceed 1ppm in a specific area, which is a potential factor in the degradation of PEMFC performance and lifetime. Investigating the mechanism and concentration threshold of cathode ammonia poisoning PEMFC is the prerequisite for preventing catalyst ammonia poisoning. In this work, the effect of 250ppb~5ppm transient contamination on PEMFC performance and impedance is studied. The results show that the attenuation performance caused by ammonia is attributed to the increase of impedance, which is mainly reflected in the mass transmission resistance, followed by the cathode activation resistance, and has little effect on the charge transfer resistance. The performance is somewhat recovered after the polarization curve testing, which is related to the voltage change and the increase in water generated during the high current density. Through the comprehensive analysis of the voltage and EIS, it is concluded that the transient tolerance concentration threshold of PEMFC to ammonia is 500ppb.</div></div>