Abstract
Microprobe measurement technique has been demonstrated to measure the diffusion constant of gaseous species in the electrolyte membrane of PEFCs (polymer electrolyte fuel cells.) Thin platinum wires are inserted between the electrolyte membranes to measure the diffusion-limited current density to obtain the value of diffusion coefficient of either hydrogen or oxygen. The results show Arthenius type of temperature dependence of the diffusion coefficient for both species. Increasing relative humidity of the supplied gas increases the diffusion coefficients, and the ratio of the hydrogen to oxygen diffusion coefficient decreases understanding the mechanism of the gas transport in the membrane.
