Study on the Influence of Anode Ammonia Impurities on Proton Exchange Membrane Fuel Cell Performance

Industrial by-product hydrogen and reformate hydrogen from ammonia are possible fuels for proton exchange membrane fuel cells (PEMFCs) which may have ammonia impurities that damage the performance. This study investigates the influence of ammonia impurities in anode fuel on the performance of PEMFCs. Comprehensive electrochemical characterizations were employed to analyze the effects of varying ammonia concentrations and relative humidity (RH) levels. The results demonstrate that ammonia impurities significantly increase electrode activation overpotentials and proton transfer resistance in the cathode catalyst layer and membrane, with more pronounced effects under low RH conditions. Ammonia adsorption on platinum catalysts reduces the electrochemical active surface area and impedes the oxygen reduction reaction, leading to increased activation losses. Additionally, ammonia binding with membrane sulfonate groups elevates proton transfer resistance. These findings underscore the critical need to control ammonia impurities in anode fuel to maintain optimal PEMFC performance.