Proton conducting intermediate-temperature solid oxide fuel cells using new perovskite type cathodes

•Sr2Fe1.5Mo0.5O6−δ (SFM) is used as cathode for H-SOFC.•SFM is compatible with BCZY electrolyte under 1100 °C.•SFM–BCZY cathode is promising for H-SOFC at intermediate temperature.•Good performance is achieved with SFM–BCZY composite cathode.•Co-sintering temperature of 1000 °C is found optimal.

Sr2Fe1.5Mo0.5O6−δ (SFM) is proposed as the electrodes for symmetric solid oxide fuel cells (SOFCs) based on oxygen-ion conducting electrolytes. In this work SFM is investigated as the cathodes for SOFCs with proton conducting BaZr0.1Ce0.7Y0.2O3−δ (BZCY) electrolyte. SFM is synthesized with a combined glycine and citric acid method and shows very good chemical compatibility with BZCY under 1100 °C. Anode-supported single cell (Ni–BZCY anode, BZCY electrolyte, and SFM-BZCY cathode) and symmetrical fuel cell (SFM–BZCY electrodes and BZCY electrolyte) are fabricated and their performances are measured. Impedance spectroscopy on symmetrical cell consisting of BZCY electrolyte and SFM–BZCY electrodes demonstrates low area-specific interfacial polarization resistance Rp, and the lowest Rp, 0.088 Ω cm2 is achieved at 800 °C when cathode is sintered at 900 °C for 2 h. The single fuel cell achieves 396 mW cm−2 at 800 °C in wet H2 (3 vol% H2O) at a co-sintering temperature of 1000 °C. This study demonstrates the potential of SFM–BZCY as a cathode material in proton-conducting intermediate-temperature solid oxide fuel cells.