Distributed performance of polymer electrolyte fuel cells under low-humidity conditions

For reduced system complexity and compactness, it is desirable to operate polymer electrolyte fuel cells (PEFC) with low humidification. In order to more fully understand and optimize performance, there is a need for combined distributed current, species, and impedance data. This paper presents results of a series of experiments at various anode and cathode humidity levels with distributed current, species, and high frequency resistance (HFR) data. This provides much insight into the characteristic operating performance of PEFCs under low-humidity operation. Results show that the degree of water saturation in the anode greatly influences local performance through local anode dryout, even for the thin 18 mu m electrolytes used in this study. A characteristic curve has been developed to predict the qualitative shape of the current profile for a coflow arrangement under fully dry to fully humidified inlet combinations. These results should also be of great interest to those seeking experimental data for model validation. (c) 2005 The Electrochemical Society.