Distributed cation contamination from cathode to anode direction in polymer electrolyte fuel cells

• Effect of Cation (Ca2+) contamination on PEFC is studied using a multi-layer membrane cell.
• Pt wires are inserted between the membrane layers to monitor the through plane potential.
• The cell performance deteriorates, when cation solution is injected into the cell.
• High frequency resistance increases more than 50% due to cation contamination.

Distributed effects of cation contamination on polymer electrolyte fuel cells (PEFC) were investigated at a fixed concentration of 5 ppm of Ca2+ in the air stream of an operating fuel cell. A special purpose MEA was prepared using five layers of membrane, and four Pt wires (electrodes) were inserted between the membrane layers. These Pt electrodes were used to monitor the through plane potential due to the permeation of hydrogen and oxygen from the anode and the cathode, respectively as well as the resistance distribution across the membrane thickness. At the beginning of the test, oxygen permeated from the cathode to the first layer of the membrane. After 32 h, oxygen continued to permeate from cathode to the other layers of the membrane. The cell performance deteriorated, when CaSO4 solution was injected as a contaminant. Within 21 h of contaminant injection, the cell voltage dropped to less than 200 mV. High frequency resistance (HFR) increased more than 50% in the individual membrane layer that was located close to the cathode.