Effects of Ni-Doping in CuMn2O4 Spinel Coatings for Interconnects in Solid Oxide Fuel Cells

Chromium (Cr) poisoning from metallic interconnects is a significant issue that impairs the performance of solid oxide fuel cells (SOFCs). Employing doped spinel coatings as a protective layer on interconnects has proven to be a successful mitigation strategy for Cr poisoning. This study examines three different nickel (Ni) doping levels in CuMn2O4 spinel to determine the most effective doping content. The compositions explored were CuNi0.2Mn1.8O4, CuNi0.4Mn1.6O4, and CuNi0.6Mn1.4O4. Results indicate that Ni doping enhances the phase stability and electrical conductivity and reduces Cr diffusion in the CuMn2O4 spinel. Notably, CuNi0.2Mn1.8O4 demonstrated best overall performance, exhibiting the highest electrical conductivity of 94-103 S/cm in the 700-800 degrees C range, forming the densest coating layer, and exhibiting the strongest diffusion barrier to Cr migration. Thus, CuNi0.2Mn1.8O4 is identified as the optimally Ni-doped Cu-Mn spinel coating.