Design, development and investigation of novel electrolytes and electro-catalysts for intermediate and low temperature solid oxide fuel cells

In the present PhD dissertation the properties of novel electrolytes and electrocatalysts for applications in Intermediate and Low Temperature Solid Oxide Fuel Cells (IT & LTSOFCs) are investigated. Initially, in the 1st Chapter, the aims and the motives that drove to the investigation of the specific materials are presented, whereas in the 2nd Chapter, a brief review of the research efforts that have been made towards the reduction of the operation temperature of SOFCs is cited. The experimental apparatus and the experimental techniques that were used in order to determine the structural, electrical and electrochemical properties of the materials under investigation are presented in the 3rd Chapter, followed by the experimental results. In Chapters 4 and 5, the structural and electrical characterization of novel solid electrolytes for IT-SOFCs are studied, while in Chapters 6 and 7, the effect of carbon dioxide on the electrocatalytic properties of a recently discovered and highly promising cathode are investigated, during the operation of a single SOFC in the low and intermediated temperature interval. More precisely, in the 4th Chapter the structural and electrical properties of samariumdoped barium cerate perovskites, BaCe1-xSmxO3-δ (where 0.00≤x≤0.20), prepared by following the solid state reaction method, are investigated. According to the Χ-ray diffraction patterns, the solid solutions BaCe1-xSmxO3-δ present cubic perovskite structure with orthorhombic distortions. The relative density of the prepared samples corresponds to ~87% in the case of compositions 0.02≤x≤0.05, whereas in the case of 0.05