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O: Fachverband Oberflächenphysik
O 45: Solid-Liquid Interfaces II: Reactions and Electrochemistry
O 45.10: Vortrag
Dienstag, 17. März 2020, 13:00–13:15, WIL C107
Influence of Porosity on the Protonic Surface Conductivity of Yttria-Stabilized Zirconia Thin Films — •Erdogan Celik1, Torsten Brezesinski2, and Matthias T. Elm1 — 1Center for Materials Research, Justus-Liebig-University Gießen, Germany, Heinrich-Buff-Ring 16, 35392 Gießen — 2Institute of Nanotechnology; Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen
Yttria-stabilized zirconia (YSZ) is among the best-performing solid-state electrolytes for applications in fuel cells or heterogeneous catalysis because of its outstanding ionic conductivity at high temperatures. In addition, nanostructured oxides exhibit an even enhanced protonic conductivity at low temperatures. Nevertheless, the influence of material morphology on the protonic transport is still controversially discussed. To study the effect of surface and porosity on the protonic conductivity, porous YSZ thin films were prepared pulsed laser deposition. Such films represent an ideal model system because of their high surface-to-volume ratio. Electrochemical impedance spectroscopy was carried out as a function of temperature, oxygen activity and humidity of the surrounding atmosphere. The total conductivity is found to increase under humidified atmosphere conditions at all temperatures due to protonic surface conduction, especially below 100 ∘C. When coating a nanometer-thick layer of titania (TiO2) on the porous YSZ network using atomic layer deposition (ALD), the proton transport is suppressed, thus indicating the significant influence of surface properties on the protonic transport.