Abstract

We performed in situ through-plane visualization of liquid water distribution in a polymer electrolyte fuel cell operating at 30℃, 50℃, and 70℃ by using high-resolution soft X-ray radiography. Less liquid water accumulation in the membrane electrode assembly was observed in the elevated operating temperature. These observations indicated that water generated in the electrode is mainly transported as vapor phase at higher temperature conditions. It was also confirmed that liquid water accumulation was less significant in the micro porous layer than those in the gas diffusion layer.