OXYGEN PERMEATION IN AG YSZ AIR CATHODES

Potential-step chronoamperometry of Ag/YSZ (YSZ = yttria stabilized zi rconia) air cathodes was measured at 350-500-degrees-C in air. A decay equation was derived by solving Fick's diffusion equation assuming a diffusion mechanism in which oxygen diffuses through the solid silver and is reduced to oxide ion at the Ag-YSZ. The theoretical decay curve s calculated from the decay equation were fitted to the experimental d ata by optimizing the equation parameters. The diffusion constant calc ulated from the time constant, which was obtained as one of the optimi zed parameters, agreed with the known values. This agreement suggests that the silver electrode shows bulk oxygen permeation.