LAUSR

Abstract The development of cathode materials, with high catalytic activity toward oxygen reduction reaction (ORR), structural stability and CO2 tolerance, is an important research direction for the successful realization of intermediate-temperature solid oxide fuel cells (IT-SOFCs). Herein, a novel double perovskite mixed ionic conductor, i.e., Sr2Fe1.3Ga0.2Mo0.5O6-δ (SFGM), is developed by Ga-doping at Fe-sites of Sr2Fe1.5Mo0.5O6-δ (SFM) and evaluated as a cathode material in IT-SOFCs. At 750 °C, the area specific resistance (ASR) of SFGM cathode is found to be 0.099 Ω cm2, which is ~50% lower than SFM cathode (0.224 Ω cm2) in 20% O2/N2 atmosphere. Moreover, SFGM exhibits outstanding CO2 tolerance due to its excellent CO2 adsorption resistance compared with SFM. The ASR of SFGM remains stable at ~0.13 Ω cm2 during 100 h of continuous operation in 5% CO2-containing air. In addition, a large-sized SFGM cathode (30 cm2) is utilized in anode-supported flat-tube SOFCs to demonstrate the potential of SFGM in practical applications. At 750 °C, the as-prepared SFGM-based single-cell provides a stable power of 12 W for 291 h in 5% CO2-containing air. The superior electrochemical performance and outstanding CO2 tolerance of SFGM are promising features for the rapid development of IT-SOFCs.