[3Ep01-07] Surface Science and Energy Storage: Electrode Surface Science Division's Session

[3Ep03] Operando coherent anti-Stokes Raman scattering (CARS) spectroscopy of different OH species in anion exchange membrane fuel cells (AEMFCs) during operation.

*Solomon Wekesa Wakolo¹, Donald Tryk², Hiromichi Nishiyama³, Junji Inukai^2,4 (1. Integrated Graduate School of Medicine, Engineering, and Agricultural Sciences, University of Yamanashi, Japan. , 2. Hydrogen and Fuel Cell Nanomaterials Research Center, University of Yamanashi, Japan., 3. LIB Technical Center, GS Yuasa International Ltd., Japan., 4. Clean Energy Research Center, University of Yamanashi, Japan)

In this paper, an in-house build 785 nm CARS spectroscopy system developed at the University of Yamanashi was used to investigate steady state and transient water distribution in an operational AEMFC for the first time. A QPAF-4 membrane of 2.0 meq g^-1 IEC and 30 µm thickness was used as the anion exchange membrane. It was observed that during power generation, water in the membrane on the anode side increased steadily with increasing current density. At the center of the membrane, water decreased with increasing current density up to 0.05 A cm^-2. Above 0.05 A cm^-2, water at the center of the membrane increased. On the cathode side, water decreased with increasing current density up to 0.1A cm^-2. Above 0.1 A cm^-2, water increased steadily. The water distribution during the 15s of transient response mirrored the steady-state response above; however, the decrease in water on the cathode side was more severe than the increase in water on the anode side. The recovery was also faster than expected.