The ability to control the electrical properties of the materials that are used in fuel cell devices is crucial. Among the materials that are used as electrodes in fuel cells, oxygen-deficient perovskites are an important family due to their ability to conduct both ions and electrons. The defects created due to oxygen-deficiency lead to interesting electrical properties in these compounds. We have examined several series of oxygen-deficient perovskites and demonstrated that there are correlations between their electrical properties and the arrangement of defects in the structure. We have found that the defects, generated as a result of oxygen-deficiency, can be controlled and distributed in the material structure in an ordered manner. There is a systematic relationship between electrical conductivity and defect-order in this class of compounds. Considering that some devices such as solid oxide fuel cells (SOFCs) operate at high temperature, variable-temperature impedance studies have also been carried out. These studies reveal that there is an optimum degree of defect-order that can lead to the best electrical conductivity at high temperature. Multiple techniques including neutron diffraction, x-ray photoelectron spectroscopy, and impedance spectroscopy have been utilized to demonstrate the structure-property relationships in this important family of functional materials.

Design and synthesis of defect-ordered perovskites: Controlling the electrical properties through modification of defect-arrangement for fuel-cell applications

2019 Spring National Meeting

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