Synthesis and characterization of Ag-Y co-doped Mn-Co spinel for solid oxide fuel cell application

Mn-Co spinel coating for solid oxide fuel cell interconnects shows a suitable thermal expansion match, acceptable electrical conductivity, and good structural stability. In this paper, the addition of different amounts of Ag and Y as dopants on the physical and electrical properties of the Mn-Co spinel is investigated to improve the coating performance. First, the doped and co-doped powders were successfully synthesized using the Pechini sol-gel method. The synthesized powders were then characterized using X-ray diffraction and field emission scanning electron microscopy. The results confirmed that Ag was not completely doped into the spinel structure and instead acted. as an additive, whereas Y caused Mn3O4 impurity phase formation at higher mol%. Next, the powders were pressed and sintered at different temperatures (950 and 1050 °C) to evaluate the effect of dopants on the sintering and electrical behavior of the samples. Finally, the electrical conductivity of the samples was evaluated using a 2-probe direct current technique. Although results showed that room temperature electrical conductivity increased upon doping, adding Y had a better effect on conductivity than Ag.