Flash light sintered SDC cathodic interlayer for enhanced oxygen reduction reaction in LT-SOFCs

Abstract

To commercialize solid oxide fuel cells, many methods for reducing the production time of manufacturing a fuel cell membrane-electrode-assembly (MEA) using a non-vacuum process have been studied and still the post-heat treatment process is an issue. This paper discusses an alternative sintering method to replace the conventional thermal sintering step for ceramic thin film fabrication, which is time consuming and costly. We fabricated samarium-doped ceria (SDC) thin films, which has high ionic conductivity and high surface exchange coefficient for oxygen reactions at the cathode side. The films were deposited by chemical solution deposition (CSD) method utilizing electrostatic spray deposition (ESD) technique. Thermal decomposition and crystallization steps are required as a post-heat treatment process to obtain desired material properties. For this purpose, the flash light sintering method is adopted and compared with the conventional thermal sintering process using halogen furnace. With this flash light sintering method, the conventional post-heat treatment process time can be significantly reduced from tens of hours to a few seconds. Scanning electron microscopy, X-ray diffraction, and transmission electron microscopy analyses were carried out for material characterizations. Additionally, electrochemical impedance analysis and current-voltage behavior measurements were conducted. By successful fabrication of SDC cathodic functional layer utilizing flash light irradiation process, the 2-folds of fuel cell performance enhancement was obtained in terms of the peak power density at the measurement temperature of 450 °C.