Cationic contamination is a well-known phenomenon that causes performance degradation and decrease in lifetime in polymer electrolyte based electrochemical systems. Calcium is a significant cationic impurity due to its prevalence. In this work, the role of calcium is investigated in-situ by injecting into the cathode of a single polymer electrolyte fuel cell (PEFC) through a nebulizer as a solution of calcium sulphate (CaSO_4) in deionized (DI) water. Stability tests are conducted to determine the contaminant effects at different current densities with different Ca~(2+) concentrations. It is found that 5 ppm Ca~(2+) in air at 1 A/cm~2 is high enough to lead to high cell performance loss as well as severe membrane degradation. Chemical precipitation is found at the contact regions between the gas diffusion layer (GDL) and flow plate of the cathode at all test conditions.
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