Power generation characteristics of solid oxide fuel cell with internal steam reforming of methane

The V-I and polarization characteristics were measured for the solid oxide fuel cell with internal reforming of methane. Although the metallic surface area of Ni was low for the Ni-YSZ cermet prepared by reduction of NiO-YSZ, the activity for steam reforming reaction was high to attain equilibrium conversion at 1000 degrees C. The high operation temperature not only reduced the polarization resistance bur also attained the high conversion of methane and selectivity to CO. The changes in selectivities to CO and CO2 and formation rate of H-2 were qualitatively explained by the equilibrium of steam reforming and the shift reaction. Significant contribution of concentration overvoltage was suggested for the high methane content, whereas a limiting current was observed for the dilute methane condition at high current densities.