Porous YFe_0.5Co_0.5O₃ thin sheets as cathode for intermediate-temperature solid oxide fuel cells

In this work, porous YFe_0.5Co_0.5O₃ (YFC) thin sheets were synthesized by citric acid method. The crystal structure, morphology, thermal expansion, electrical conductivity, and electrochemical properties of YFC were investigated to evaluate it as a possible cathode on BaZr_0.1Ce_0.7Y_0.2O₃ (BZCY) electrolyte for intermediate-temperature solid oxide fuel cells (IT-SOFCs). An orthorhombic perovskite structure was observed in YFC. The conductivity of YFC is 183 S cm ⁻¹ at 750 °C in air. The coefficient of thermal expansion of composite cathode YFC-BZCY is closer to BZCY electrolyte than YFC. The composite cathode represents a relatively low polarization resistance (R_p) of 0.07 Ω cm² at 750 °C in air due to the porous thin sheet-like cathode. The oxygen reduction reaction process and the reaction activation energy of cathode were also analyzed. An anode-supported cell of NiO-BZCY∣BZCY∣YFC-BZCY is fabricated by a simple method of co-pressing. The power density of the cell is 303 mW cm⁻² at 750 °C as the thickness of electrolyte is 400 μm. The results suggest that YFC is a promising cathode candidate for IT-SOFC.