Preparation and performance of triple-layer graded LaBaCo2O5+δ–Ce0.8Sm0.2O1.9 composite cathode for intermediate-temperature solid oxide fuel cells

The triple-layer graded LaBaCo2O5+δ–Sm0.2Ce0.8O1.9 (LBCO–SDC) composite cathode was prepared by screen-printing method for intermediate-temperature solid oxide fuel cells. The result of X-ray diffraction indicated the LBCO cathode was chemically stable with the SDC electrolyte. Through optimizing the composition and microstructure, the electrochemical performance of cathode was significantly improved. For triple-layer graded LBCO–SDC composite cathode, the area-specific resistance (ASR) values were 0.881 Ω cm2 at 600 °C, 0.174 Ω cm2 at 700 °C and 0.047 Ω cm2 at 800 °C in air, about 14.8%, 41.0% and 65.7% lower than that of the monolayer LBCO cathode, respectively. The cathodic overpotential was also decreased from 51.0 mV for the monolayer cathode to 33.6 mV at a current density of 0.20 A cm−2 at 700 °C. The graded composite cathode showed great potential in improving the cathode performance for IT-SOFCs.

► The cathode performance was improved by optimizing the composition and structure.
► The graded TEC minimize the mismatch between the cathode and electrolyte.
► The graded cathode showed superior electrochemical performance to monolayer cathode.
► The graded cathode showed great potential in improving the cathode performance.