Conductivity degradation of NiO-containing 8YSZ and 10YSZ electrolyte during reduction

Yttria-stabilized zirconia (YSZ) electrolyte containing dissolved nickel as a result of co-sintering in air with NiO was shown by TEM and magnetic measurements to develop isolated, nano-sized metallic nickel precipitates during treatments in hydrogen-containing atmosphere. During exposure to hydrogen containing atmosphere at 1000 °C for 500 h, an exponential decrease in oxygen ion conductivity was observed in Ni-doped 8YSZ, while no conductivity change was observed in Ni-doped 10YSZ.