EFFECTS OF ANODE MATERIAL AND FUEL ON ANODIC REACTION OF SOLID OXIDE FUEL-CELLS

Anodic properties of solid oxide fuel cells have been evaluated for several anode/electrolyte systems. Anodic over-voltage of metal/yttria-stabilized zirconia (YSZ) interface was related with metal-oxygen bonding strength and was the smallest for the Ni anode in the present study. The anodic polarization conductivity of Ni-YSZ cermet/YSZ electrolyte interface strongly depended on oxygen partial pressure, P(O2), in fuel, but was independent of the kind of fuel (H-2-H2O, CO-CO2, and CH4-H2O). The activation of oxygen ion appears to be the rate limiting step in the overall reaction. The overvoltages of Ni/ and Pt/samaria-doped ceria (SDC) were very small as compared with those of Ni/ and Pt/YSZ. The anodic properties were also influenced by the oxide material mixed with Ni as a cermet component. The sequence of anodic polarization conductivities of Ni-oxide cermet systems was Ni-PrO(x) > Ni-SDC > Ni-YSZ.