Effect and mechanism of Cr deposition in cathode current collecting layer on cell performance inside stack for planar solid oxide fuel cells

Abstract

Quantitative effect and mechanism of Cr on cell performance inside stack are investigated by incorporating Cr in the cathode current-collecting layer (CCCL). The results show that the maximum output power density (MOPD) of the unit cell inside a stack decreases as the Cr content increases beyond 253.81 μg cm−2. The MOPD is independent of Cr when its content is less than 253.81 μg cm−2 at the original operation stage. The degradation of the repeating unit inside the stack increases with increasing Cr content. When the Cr content is higher than 182.22 μg cm−2, cell degradation increases. However, cell degradation is independent of Cr content when its content is less than 182.22 μg cm−2. The addition of Cr to the CCCL increases the ohmic resistance of the CCCL and the contact between the cathode and the electrode during the initial stage. The effect of Cr on cell degradation increases with time, but Cr content has no influence on the contact resistance between the interconnect and the cathode. Cell degradation is mainly dependent on ohmic resistance, and is independent of polarization resistance. Therefore, the addition of Cr to the CCCL increases the cell ohmic resistance, but does not affect cell polarization resistance.