A highly active and CO2-tolerant perovskite cathode for solid oxide fuel cells operating below 700 °C

Exploring high-performance and durable cathode materials can accelerate the commercialization of intermediate/low-temperature solid oxide fuel cells (SOFCs). Herein a highly active and CO2-tolerant perovskite cathode, Pr0.94Ba0.7Ca0.3CO2O5+delta (P0.94Ba0.3C), is well-designed and developed for SOFC5 operating below 700 degrees C. It is discovered that cation-ordered/disordered perovskite phases co-exist in P0.94Ba0.7Ca0.3C, induced by calcium doping. As a result, the P0.94Ba0.7Ca0.3C cathode exhibits a polarization resistance as low as 0.022 Omega cm(-2) at 700 degrees C in air. When tested under realistic conditions, an anode-supported single cell delivers a peak power density of 1202 mW cm(-2) at 700 degrees C, along with excellent long-term stability for 120 h. Furthermore, the CO2 tolerance of P0.94Ba0.7Ca0.3C is investigated in CO2-containing atmosphere, demonstrating an initial polarization resistance of 0.035 Omega cm(-2) in air with 10 vol % CO2 at 700 degrees C, which increases to 0.053 Omega cm(-2) after a 13 h operation. The degradation rate is merely similar to 1/4 of that for the state-of-the-art Ba0.5Sr0.5Co0.8Fe0.2O3-delta (BSCF) cathode. The outstanding ORR kinetics and durability highlight the potential of P0.94Ba0.7Ca0.3C as a promising cathode candidate for SOFCs operating below 700 degrees C. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

The highly active and CO2-tolerant Pr0.94Ba0.7Ca0.3CO2O5+delta (P0.94Ba0.3C) cathode has shown low polarization resistance and excellent long-term stability for solid oxide fuel cells operating below 700 degrees C. Its CO2 tolerance has also been demonstrated, making it a promising candidate for SOFCs operating at lower temperatures.