Abstract
Durability and reliability of SOFC electrode/electrolyte interfaces largely depend on the phase stability. Equilibrium calculation suggests the reactivity and driving force of the interfaces. To estimate the long-term durability, it is desirable to know the reaction rates and mass transports at the interfaces, such as diffusion of elements from electrode to electrolyte. For example, it is well known that the cathode component elements can diffuse into YSZ electrolyte to form solid-solution or second phase at the interfaces. When the second phase can be formed at the interface, the electrical conductivity and thermal expansion behaviors can be changed with the composition. The present study is to evaluate the diffusivity of elements at the cathode/electrolyte interfaces, and to estimate the stability and durability at the interface in the long-term operation. A simple calculation was made to estimate the composition change and physical property change at the cathode/electrolyte interfaces based on the observed diffusion phenomena.
