A high performance composite cathode with enhanced CO₂ resistance for low and intermediate-temperature solid oxide fuel cells

CO₂-resistant perovskite cathode has a significant role in solid oxide fuel cell (SOFC) application particularly for operation in an air atmosphere contains higher than normal amount of CO₂ such as in single-chamber SOFC (SC-SOFC). This work features a systematic study of the electrochemical performance of SrCo_0.8Nb_0.1Ta_0.1O_3-δ (SCNT)-Ce_0.9Gd_0.1O_2−δ (GDC) composite cathode under CO₂ exposure for SOFC operation in low-temperature (LT, 500 °C and below) and intermediate-temperature (IT, 500–700 °C) ranges. The complementary results from powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, in situ high temperature XRD, electrochemical impedance spectroscopy, and the single cell test show that SCNT-GDC cathode exhibit slightly lower electrochemical performance but higher CO₂ resistance than SCNT, which enables practical SOFC application. At 550 °C, SCNT-GDC-based single cell has a peak power density of 630 mW cm⁻² and reduces to a stable power density of 525 mW cm⁻² after exposure to air containing 1 vol% CO₂ for 2 h. The collective characterization and electrochemical data presented here highlight the potential of SCNT-GDC composite cathode for use in SC-SOFC and to enhance the performance stability in LT and IT-SOFCs.