LaBa0.8Ca0.2Co2O5+δ cathode with superior CO2 resistance and high oxygen reduction activity for intermediate-temperature solid oxide fuel cells

Abstract

The development of highly efficient cathode materials with durable performance and high resistance toward environmental impurity is crucial for realizing the practical applications of intermediate temperature - solid oxide fuel cells (SOFCs). Since CO2 as the oxidation product of hydrocarbons is unavoidable in the surrounding air atmosphere for SOFCs operating on hydrocarbon fuels, CO2 tolerance of the air electrode is a big concern. Herein, LaBa0.8Ca0.2Co2O5+δ (LBCC) double perovskite is proposed as a promising cathode with superior CO2 tolerance and favourable oxygen reduction activity. It shows a relatively low area specific resistance of 0.128 Ω cm2 at 600 °C in a CO2-free synthetic air atmosphere, tested based on a symmetrical cell configuration (LBCC | Gd0.2Ce0.8O1.9 | LBCC). In addition, under open-circuit voltage condition, it can run stably for more than 120 h in the air containing 1% CO2 (1% CO2, 21% O2 and 78% N2) at 650 °C. More attractively, the LBCC shows high reversibility in performance by removing CO2 from air. An anode-supported single SOFC with thin film doped ceria electrolyte (∼25 μm) and LBCC cathode shows a favourable peak power density of 1063 mW cm−2 at 700 °C by using ambient air as the cathode atmosphere and hydrogen as the fuel.