Oxygen transport in composite materials for oxygen separators and syngas membranes

The mixed conducting YSZ / LSM is a model material for use in dense ceramic membranes for syngas production at elevated temperatures. Previous determination of oxygen transport data for this material have shown that the composite posses a significantly different value for the oxygen surface exchange coefficient (k) and the oxygen self diffusion (D) than the individual materials. One possible explanation is due to the fundamental limitations governing the analysis of isotope diffusion profiles in the oxides (in particular LSM), which can lead to errors in the estimation of both D and k. To verify this explanation, experiments have been undertaken on LSM to perform high accuracy measurements of the oxygen transport properties.