SrCo0.7Fe0.2Ta0.1O3−δ perovskite as a cathode material for intermediate-temperature solid oxide fuel cells

• Fe and Ta co-doped SCFT perovskite as cathode material for IT-SOFC is studied.
• Fe and Ta co-doping stabilizes SCFT cubic perovskite phase at room temperature.
• Introduction of Ta can effectively improve phase stability of SCFT.
• SCFT material is chemically compatible with LSGM electrolyte at 950 °C for 10 h.
• SCFT material shows good conductivity, electrochemical performance and stability.

Perovskite oxide SrCo0.7Fe0.2Ta0.1O3−δ (SCFT) was synthesized by a solid–state reaction and investigated as a potential cathode material for intermediate-temperature solid oxide fuel cell (IT-SOFC). The single phase SCFT having a cubic perovskite structure was obtained by sintering the sample at 1200 °C for 10 h in air. Introduction of Ta improved the phase stability of SCFT. The SCFT exhibited a good chemical compatibility with the La0.9Sr0.1Ga0.8Mg0.2O3−δ (LSGM) electrolyte at 950 °C for 10 h. The average thermal expansion coefficient was 23.8 × 10−6 K−1 between 30 and 1000 °C in air. The electrical conductivities of the SCFT sample were 71–119 S cm−1 in the 600−800 °C temperature range in air, and the maximum conductivity reached 247 S cm−1 at 325 °C. The polarization resistance of the SCFT cathode on the LSGM electrolyte was 0.159 Ω cm2 at 700 °C. The maximum power density of a single-cell with the SCFT cathode on a 300 μm-thick LSGM electrolyte reached 652.9 mW cm−2 at 800 °C. The SCFT cathode had shown a good electrochemical stability over a period of 20 h short-term testing. These findings indicated that the SCFT could be a suitable alternative cathode material for IT-SOFCs.

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