Abstract
Direct methanol fuel cell (DMFC) using polymer electrolyte membrane (PEM) is gaining recognition as a power source of portable electronics. However certain methanol through the PEM (i.e. methanol crossover) is known to cause the degradation of efficiency and output. Since, it is significant to develop a measurement method of mass diffusion coefficient in PEM. Therefore, we have newly developed the Soret Forced Rayleigh Scattering method (SFRS) using CO2 laser for measuring mass diffusion coefficient in PEM. SFRS is a noncontact and high-speed ( ~100ms) measurement technique. In the present study, we present difficulties and resolutions using heterodyne detection etc. in applying SFRS to solutions in PEM, and report preliminary result of diffusion coefficient of 13 wt% methanol aqueous solutions in Nafion 117 by newly constructed apparatus.
