Susan Wang Wenquan Gong Manoj Yadav


We investigate complex oxide materials that have applications in high temperature ionic devices, such as fuel cells, oxygen transport membranes and sensors. The major part of our work centers on mixed metal oxides with the ABO3 perovskite structure. At present the database of perovskite oxide ionic properties is limited and we investigate new compositions to establish structure-property relationships. We also investigate the synthesis of new oxide structure types. The discovery of a new class of (Ba,Sr)-Co-O oxides is one recent example.


We use a variety of techniques to characterize the surface reactivity and bulk transport properties of materials, which together determine device performance. We use oxygen permeation through membranes, electrical conductivity relaxation, dc conductivity, ac impedance spectroscopy and other techniques to establish transport properties at high temperature in a variety of atmospheres. We also determine compound stoichiometry using thermogravimetric analysis and coulometric titration techniques. Isotope exchange experiments also give important and complementary information about ionic transport. We collaborate with C. A. Mims and P. van der Heide to investigate transport across interfaces using secondary ion mass spectroscopy (SIMS). Experimental measurements are combined with modeling studies to interpret the transport behavior.


Research Supported by:  National Science Foundation, Department of Energy,
Robert A. Welch Foundation, Texas Center for Superconductivity.



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