Characterization of solid oxide fuel cell device having a three-layer film structure grown by RF magnetron sputtering

Abstract

Solid oxide fuel cell (SOFC) having a three-layer film of Ni/YSZ/Ni structure was prepared on NiO and Al 2O 3 substrates by the RF magnetron sputtering growth. The constitutional YSZ electrolyte and Ni electrode films were characterized based on dependence on the RF power and annealing treatment. A thin YSZ electrolyte film grown on NiO substrate at a lower RF power of 200 W indicated a columnar structure with longitudinal pinholes in the film. By annealing treatment at 1600°C, YSZ film was improved as a denser film having a bulk electrolyte structure without pinholes. Ni electrode grown at 300 W showed a low resistivity of 3.6 Ω cm at 1000°C, because the contact resistance at grain boundary in the film decreased with increasing RF power. YSZ film grown on Al 2O 3 substrate at a higher RF power of 600 W was reformed to denser electrolyte film by annealing treatment. An SOFC using the annealed YSZ film exhibited a reproducible power generation property having 0.9 V of the nearly theoretical voltage at 1000°C.