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Composite anodes of La0.75Sr0.25Cr0.5Mn0.5O3−δ –Ce0.8Sm0.2O1.9 (LSCM–SDC) were prepared and investigated as anode materials for intermediate-temperature solid oxide fuel cells (IT-SOFCs) with YSZ electrolyte. Results showed that the addition of SDC significantly enhanced the electrochemical performance of LSCM anode. The anode containing 40 wt.% SDC demonstrated optimal performance. The polarization resistance and anodic overpotential (at a current density of 0.05 A cm−2) of this anode were 0.95 Ω cm2 and 0.12 V in H2 at 800 °C, respectively, whereas those of pure LSCM anode were 3.66 Ω cm2 and 0.38 V, respectively. The electrochemical performance of the LSCM–40SDC composite anode was further improved when a thin SDC interlayer was coated between the anode and YSZ electrolyte. The resulting polarization resistance and anodic overpotential with the SDC interlayer were 0.30 Ω cm2 and 0.035 V in H2 at 800 °C, demonstrating a reduction by factors of 3.2 and 3.4, respectively. The impedance data displayed that the coated SDC interlayer mainly affected the low frequency electrode process, indicating that the SDC interlayer played an important role in the promotion of the dissociation and diffusion processes of H2 oxidation reaction. [ABSTRACT FROM AUTHOR]

Abstract: ZnO doping can significantly diminish the deleterious effect caused by impurities on the grain-boundary conduction of polycrystalline Ce0.8Gd0.2O1.9 electrolyte. Analysis by field emission transmission electron microscopy equipped with energy-dispersive X-ray spectroscopy reveals that the siliceous and ZnO phases are separately aggregated at the triple grain junction areas in ZnO-added specimens. This finding implies that the scavenging process does not occur via the expected formation of zinc silicates, but via a novel mechanism in which resistive siliceous phases strongly aggregate in non-wetting configurations induced by ZnO. A three-dimensional schematic is established to elucidate the role of ZnO in the CeO2–Gd2O3 system. [Copyright &y& Elsevier]