Electrochemical properties of a SOFC cathode in contact with a chromium-containing alloy separator

Substrate-type solid oxide fuel cells (SOFCs) can reduce the operating temperature of SOFCs to enable alloys to be used as separators. When chromium-forming alloys are used as the separators, however, the performance of SOFC cathodes degrades rapidly. The degradation of a porous La_0.6Sr_0.4MnO_3+δ (LSM)/YSZ electrode in contact with the alloy current-collector has been investigated using the frequency dispersion diagram of the complex impedance of the electrode. The equivalent circuit analysis based on a Randles-type equivalent circuit made clear that the Cr₂O₃ deposition at the interface between the LSM and the YSZ electrolyte causes an increase in both diffusion and charge-transfer resistances.