Fabrication of ultra-thin electrolytes for low temperature operation of SOFCs at 600~650C

Abstract

In recent years, intensive research efforts have been made to develop ultra-thin film electrolyte in order to lower the operating temperature of SOFCs down to 600~650oC. Although current thin film techniques such as solution or vacuum deposition technique offers numerous advantages over the conventional thick film printing methods to fabricate ultra-thin films below 1 micrometer thick, its practical application for SOFC fabrication have been limited due to the difficulties in controlling the macro-defects, which are frequently generated during the film deposition process. In this study, application of advanced thin film technologies based on pulsed laser deposition (PLD) and chemical solution deposition (CSD) are investigated to safely reduce the operating temperature down to 600~650oC without sacrificing the performance. We optimized the processing conditions for thin film deposition to the way to reduce the microstructural anisotropy and its related macrodefects in deposited electrolyte films. According to the performance analysis, excellent gas-tightness of the thin electrolyte was confirmed from both of the cells produced via CSD and PLD, by showing open circuit voltage close to the theoretical value. The electrochemical performance was also superior to conventional SOFCs in both cases. The presentation will discuss the up-to-date progress of related research activities for the development of advanced SOFC based on thin film technology at KIST.