Combined effect of temperature difference across interface and finite size of the ions on interdiffusion in SOFC

Abstract

In the present study, the combined effect of the temperature difference across the electrode-electrolyte interface and the finite size of ions non-idealities on the cation interdiffusion is investigated using a mathematical model. Here, we build on and add significantly to our previous work 1 where the study was limited only to the finite effect of ions. Considering each non-ideality/effect separately, the diffusion of manganese (Mn3+) ions decreases about 50 nm for a temperature difference (∆ T) of 50 K, and 31 nm for a finite size parameter ( ν) of 1.826. However, it is decreased by 54 nm considering both effects combindly for ∆ T = 50 K and ν = 1.75. Further, under individual effects, the highest electric potential drop is 0.32 for a ∆ T = 50 K and 0.27 for a ν = 1.75. Under combined effects, the electric potential drop is about 0.85 for ∆ T = 50 K and ν = 1.75. A significant variation is observed in the diffusion of Zr4+, Y3+ and Mn3+ ions and the overall electric potential. It is anticipated that the consideration of these effects/non-idealities will help in the better understanding of cation interdiffusion, and contribute towards performance enhancement of SOFCs.