Effect of Rare Earth Y and Metal X (Co, Mn, Ni, Cu) Elements on Cr Diffusion Behavior of SOFC Metallic Interconnect

ABSTRACT At present, the metallic interconnects of the solid oxide fuel cell (SOFC) can result in Cr poisoning problem of cathode after long‐term high‐temperature oxidation. Such problem seriously affects the efficiency of battery power generation. In order to optimize the performance of the metallic interconnect, this paper firstly studies the doping effect of rare earth element Y and metal element X (Co, Mn, Ni, Cu) on the diffusion behavior of Cr at the FeCr/Cr 2 O 3 interface by the first principles method. The Cr diffusion pathway and energy barriers under different elemental doping models are calculated by CI‐NEB method. Based upon the theoretical results, the Mn 1.8 CoY 0.2 O 4 spinel coating is further deposited on the surface of Crofer 22 APU substrate by sol–gel and electrophoretic deposition method to verify the theoretical results. The performance of the coating samples after high‐temperature oxidation are tested and analyzed. The experimental results show that the Mn 1.8 CoY 0.2 O 4 spinel coating significantly improves the high‐temperature antioxidation, Cr resistance performance, and electrical conductivity of the interconnect, providing a feasible solution for solving the Cr poisoning problem in cathode and accelerating the application of Crofer 22 APU alloy materials in SOFC metallic interconnects.