Fabrication of Gd2O3-Doped CeO2 Thin Films for Single-Chamber-Type Solid Oxide Fuel Cells and Their Characterization

Gd2O3-doped CeO2 (GDC) thin-film electrolytes with lateral-type electrode geometry for integrated single-chamber solid oxide fuel cells (SOFCs) were prepared by dc/radio-frequency reactive magnetron sputtering. The morphological and electrical properties of the GDC films with various electrode geometries were characterized by X-ray diffraction. scanning election microscopy and impedance spectroscopy. The electrolyte films had in average grain size of similar to 50 nm and exhibited a conducting behavior similar to bulk GDC. The activation energy for electrical conductivity was estimated to be 0.77 eV along, the direction normal to the film surface. The electrical conductivity along, both the lateral and vertical directions was similar to those of bulk GDC. This suggests that a GDC thin film With such a small average grain size has negligible deleterious effects originating from the gain boundaries. It was confirmed from the oxygen partial pressure-independent electrical conductivity of the films that the electrical conduction originated mainly from oxygen ions, not electrons. Overall. the fabricated cell with the interdigitated electrode geometry might be suitable for the single-chamber SOFC cell. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3056036] All rights reserved.