Chlorine-contaminated anode and cathode PEMFC-recovery perspective

Progressive thinking about future generation proton exchange membrane fuel cells (PEMFCs) leads us to cost-effective compact fuel cells operating with dry reactants using self-humidifying membranes. Presently, however, PEMFCs are limited by number of factors. One such factor is the reactant impurities present in the feed streams. Chlorine is one such impurity affecting both anode and cathode PEMFC adversely. Several studies have reported adverse impact of anionic chloride in PEMFCs but scarce or no literature is available on the effect of chlorine gas as such on PEMFCs. In the present work, we report for the first time to the best of our knowledge the adverse effects of chlorine when introduced on anode and cathode independently using a single-cell PEMFC. About 94% (anode) and 82% (cathode) loss in performance is observed at an operating voltage of 0.6 V after contamination with 100 ppm chlorine at the anode and cathode respectively. It is found that operating at higher current density plays a significant role in the PEMFC recovery process. The duration of recovery changes for anode-contaminated cell and cathode-contaminated cell, which is 2 and 4 h respectively. The protons on the anode side and the hydroxyl ion at the cathode side help in replacing the chloride species adsorbed on the platinum surface. The electrochemical impedance studies show an increase in the charge transfer resistance after cathode contamination, whereas in the case of anode contamination, the cell resistance increases while maintaining the same charge transfer resistance.