ScSZ Electrolyte And It's Application In IT-SOFCs

State of the art anode-supported solid oxide fuel cell (SOFC) with thin YSZ electrolyte leads the development of intermediate temperature SOFCs. In this type, the polarization loss originated from the LSM-YSZ cathode is the key issue affecting the cell performance. Much attention has been paid to the improvement of the cathode/electrolyte interface and the development of high performance cathode materials. Althouth scandia stabilized zirconia electrolyte (ScSZ) exhibits the highest ionic conductivity in the zirconia-based solid electrolytes, ScSZ has not adopted widely in SOFCs due to the complex phase assembly and the poor sintering property. In this dissertation, ScSZ electrolytes were chosen and applied to design novel cathode/electrolyte interface and new composite cathodes in order to improve the performances of the traditional anode-supported SOFCs. ScSZ electrolytes doped with ceria were synthesized and characterized. The ceria introduction can stabilize the cubic structure of 10ScSZ electrolytes at high temperature down to room temperature. Furthermore, ceria doping can bring about a clean grain boundary and therefore reduce the boundary impedance, althogh the ScSZ conductivity decreased.Anode-supported SOFC with 25μm ScSZ thin film was fabricated through co-firing process. The cell gave an open circuit voltage (OCV) of 1.00 V and a maximum power density of 1.07 W/cm2 at 800oC. Amount of pinholes existed in the ScSZ layer even if the anode/electrolyte assembly was co-fired at 1450oC. The...