Diffusion Phenomenon of Cathode Components in YSZ Electrolyte and Effect on Mechanical Properties of SOFC

Abstract

At present, SOFC research mainly focuses on the development of new medium and low temperature cathode materials or the improvement of existing cathodes, as well as the development of new anodes resistant to carbon deposition and sulfur poisoning. However, during the discharge state, the diffusion of metal elements in the electrolyte caused by the constant current is rarely studied. In order to analyze whether there is a diffusion of electrode elements at the electrode-electrolyte interface, and the effect of this diffusion on the mechanical properties of the SOFC. Polarization test of the half-cell of YSZ electrolyte and LSM cathode was carried out at 950°C with the current load of -300 mA·cm-2 in an air atmosphere, and the polarization time was different. The powders were analyzed by XRD. A post-test analysis of the cathode-electrolyte interface was tested by using SEM, EDX and EPMA. Finally, the Vickers hardness was used to measure the mechanical properties of YSZ electrolyte. The results show that the Mn element has diffused into the YSZ electrolyte after constant current. In addition, it has a certain impact on the mechanical properties of the cell.