Drying process of water in a Nafion membrane embedded in the fuel cell analyzed by coherent anti-Stokes Raman scattering spectroscopy

摘要： A coherent anti-Stokes Raman scattering (CARS) spectroscopy system was designed to measure the transient behavior of the humidi?cation of a Na?on membrane used in a polymer electrolyte fuel cell (PEFC). We observed a variation in the intensity of the O–H stretching vibration peak of water during dry and wet gas ?ow. From our measurements, we found that our system showed a high time resolution enough to measure humidi?cation variation in a Na?on membrane in a PEFC. The high acquisition rate revealed the nonequilibrium process of the dehydration or hydration of the Na?on membrane through the temporal variation in the intensity of the O–H stretching vibration peak. The peak consisted of three peaks, suggesting that water molecules hydrated with di?erent bonding energies. The transient behavior of the peaks was probably attributed to the motion of hydration molecules in the proton channel. ? 2018 The Japan Society of Applied Physics