NdFeO3 as anode material for S/O2 solid oxide fuel cells

Sulfur-oxygen solid oxide fuel cells (S/O2-SOFCs) can improve the utilization ratio of energy via converting the combustion heat of sulfur into electrical energy directly, and sulfur trioxide which is an intermediate in sulfuric acid industry can be obtained directly via S/O2-SOFCs. The anode material NdFeO3 was prepared via sol-gel method, the phase stability of NdFeO3 in sulfur vapor or sulfur dioxide atmosphere was investigated. The single cell, consisting of NdFeO3-SDC/SDC/LSM-SDC structure, was fabricated by the screen-printing method and tested by the home-built equipment with sulfur vapor or sulfur dioxide as the fuel. As indicated by X-ray diffraction (XRD) analysis, NdFeO3 was stable in sulfur vapor or sulfur dioxide atmosphere at 800 °C, the phase composition of the mixture of NdFeO3 and SDC (Sm doped CeO2) did not change after the mixture was calcined at 800 °C for 4 h. The transmission electron microscope (TEM) photograph revealed that the average grain size of NdFeO3 powder was about 80 nm. With sulfur vapor or SO2 as the fuel, the maximum open circuit voltages (OCVs) of the single cell were 409 mV at 620 °C and 474 mV at 650 °C, respectively; the maximum power densities of single cell were 0.154 mW/cm2 at 620 °C and 0.265 mW/cm2 at 650 °C, respectively.