Another related cathode composition is the doped lanthanum ferrite; LaxSr1-xFeyNi1-yO3-δ (LSFN), with La0.6Sr0.4Fe0.8Ni0.2O3-δ (6428) as the optimum composition. The material shows electronic conductivity of 300 Scm -1 at 900 °C with a reasonable TEC of 14 × 10 -6 K -1 , 65 but they also come with their problems of forming insulating phases such as La2Zr2O7 and SrCoO3 at the interface when used with YSZ as an electrolyte, which further degrades the performance of the cell.