Abstract:

Among the superionic conductors, oxygen ion conductors play a very important role due to their possible applications in fuel cells, oxygen pumps and oxygen sensors. Among them, the δ phase of bismuth oxide Bi2O3 shows the highest electrical conductivity. This phase, crystallizing in the structure of defective fluorspar, is however stable in a narrow temperature range from 730 to 825 ° C. In order to stabilize the structure of the fluorspar below 730 ° C, Bi2O3 solid solutions are usually formed with the appropriate oxides or thin films are obtained. We have recently discovered that the delta phase - stable at room temperature - can be obtained in a completely different way, namely by thermal nanocrystallization of bismuth glasses. As part of the main research hypothesis, we propose that the cause of stabilization is the entrapment of the delta phase nanocrystallites in the glassy matrix. During the seminar, the progress of experimental and computational work aimed at verifying the research hypothesis will be presented.

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