Electrochemical performance of Ba2Co9O14 + SDC composite cathode for intermediate-temperature solid oxide fuel cells

A 50–50 wt.% Ba2Co9O14 (BCO) + Sm0.2Ce0.8O1.9 (SDC) composite was evaluated as a cathode for an intermediate-temperature solid oxide fuel cell (IT-SOFC) operating at 800 °C. The composite was supported on the electrolyte La0.8Sr0.2Ga0.83Mg0.17O2.815 (LSGM) and its performance for the oxygen-reduction reaction (ORR) was evaluated with a symmetric BCO + SDC|LSGM|BCO + SDC cell, which gave a polarization resistance of 0.068 Ω cm2 at 800 °C in air. A singe cell with a 300-μm-thick electrolyte and a composite NiO + Gd-doped ceria anode gave a nearly stable Pmax ≈ 450 mW cm−2 at 800 °C, indicating that with a thinner electrolyte, the composite cathode could provide an IT-SOFC that meets the targeted 500 mW cm−2 at 800 °C. The fabrication of the composite cathode versus BCO alone serves two functions: improved adhesion to the electrolyte and an enhancement of the ORR activity.

► A 50–50 Ba2Co9O14 (BCO) + Sm0.2Ce0.8O1.9 (SDC) composite was evaluated as a cathode for an IT SOFC. ► The composite serves two functions: improved electrolyte adhesion and enhancement of the ORR. ► The composite cathode gave a polarization resistance of 0.068 Ω cm2 at 800 °C in air. ► At 800 °C, a SOFC with the composite anode can meet the targeted Pmax > MW cm−2.