PEM fuel cell cathode contamination in the presence of cobalt ion (Co2+)

This paper reports the effects of Co2+ contamination on PEM fuel cell performance as a function of Co2+ concentration and operating temperature. A significant drop in fuel cell voltage occurred when Co2+ was injected into the cathode air stream, and Co2+ contamination became more severe with decreasing temperature. To investigate in detail the mechanism of Co2+ poisoning, AC impedance was monitored before and during Co2+ injection, revealing that both charge transfer and mass transport related processes deteriorated significantly in the presence of Co2+, whereas membrane conductivity decreased to a lesser extent. Surface cyclic voltammetry and contact angle measurements further revealed changes in physical properties, such as active Pt surface area and hydrophilicity, furthering our understanding of the contamination process.