Influences of the thickness and density of the gadolinia doped ceria barrier layer on the performance of the solid oxide fuel cell

Abstract

Ce_0.9Gd_0.1O_2-δ (GDC) is used as the barrier layer of the solid oxide fuel cell (SOFC) maturely due to its advantages of high oxygen ion conductivity and excellent chemical stability.It can prevent the interfacial reaction between the cathode perovskite material and the fluorite electrolyte material effectively. In this study, the dense GDC barrier layer with fewer flaws and better gas tightness was prepared by screen-printing method and co-sintering. Improving the density of the GDC barrier layer and reducing the flaws on the interface between the GDC barrier layer and the electrolyte can contribute to the faster oxygen ion transfer, making the SOFC shows better electrochemical performance. Furthermore, densifying the GDC barrier layer can also weaken the influences of the oxygen partial pressure and the temperature on the oxygen ions conductivity of the GDC barrier layer, making the ohmic resistance of the SOFC no longer vary obviously with the oxygen partial pressure, especially at lower operation temperature. In addition, the increasing oxygen partial pressure contributed to the gaseous phase diffusion and exchange on the cathode, lowering both the cathode polarization resistance and the total resistance of the SOFC, and improving the electrochemical performance of the SOFC. This study can deepen the understanding of the GDC barrier layer, and contributes to the large-scale production and further application of the GDC barrier layer during the commercialization of the SOFC.