Thin-Film SOFCs Using Gastight YSZ Thin Films on Nanoporous Substrates

We fabricated yttria stabilized zirconia (YSZ) thin films having submicrometer thickness without gas leakage to be incorporated in low-temperature solid oxide fuel cells (SOFCs). We obtained -thick YSZ films by oxidizing Y–Zr alloy thin films deposited onto anodic nanoporous alumina substrates having pore diameter of 20 and using dc-magnetron sputtering at room temperature. During the thermal oxidation, the alloy films were successfully transformed to defect-free oxide thin films. Volume expansion induced from the oxidation of the alloy resulted in dense oxide thin films that are free from hydrogen permeation. Conductivity of YSZ thin films at room temperature was measured and compared with the reported conductivity of YSZ ceramics. And low-temperature operation testing was performed using the fabricated fuel cell.