Electrical conductivity and electrochemical performance of SrMo0.94Fe0.06O3−δ–Gd0.2Ce0.8O1.9 composite for SOFC anode

• SrMo0.94Fe0.06O3−δ is compatible with Gd0.2Ce0.8O1.9 in both air and H2 atmosphere.
• SrMo0.94Fe0.06O3−δ can be easily obtained by reducing SrMo0.94Fe0.06O4−δ at 850 °C.
• The ionic conductivity can be improved by adding GDC into SrMo0.94Fe0.06O3−δ.
• The lowest RP of composite anode can be obtained by suitable GDC adding.
• SMF7-GDC3 has favorable electrochemical catalytic activity of hydrogen oxidation.

Fe-doped SrMoO4 (SrMo0.94Fe0.06O4−δ), synthesized by an EDTA–glycine complexing combustion process, can be easily reduced to SrMo0.94Fe0.06O3−δ (SMF) at 850 °C in pure H2 atmosphere. The incorporation of Gd0.2Ce0.8O1.9 (GDC) into SrMo0.94Fe0.06O3−δ is supposed to enhance the ionic conductivity and catalytic activity of SMF. Phase composition and chemical compatibility of SMF-GDC composite in both air and H2 atmosphere are confirmed by X-ray diffraction test. SMF-GDC composites in different mass ratios are systematically investigated in terms of electrical conductivity, electrochemical performance and power output with the fuel cells. With the addition of GDC, the ionic conductivity is able to be improved and the lowest interfacial polarization resistance is observed to be 0.647 Ω cm2 for SMF7-GDC3 composite anode at 850 °C. With SMF7-GDC3 as anode, the single cell is able to generate a maximum power density of 530 mW cm−2 at 850 °C when fed with pure H2 (30 mL min−1) and demonstrates a considerable stability with the anode exposed to H2 and upon redox cycling.

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