| AVS 55th International Symposium & Exhibition | |
| Energy Science and Technology Focus Topic | Tuesday Sessions |
| Session EN-TuP |
| Session: | Energy Focus Topic Poster Session |
| Presenter: | M.H. Engelhard, Pacific Northwest National Laboratory |
| Authors: | M.H. Engelhard, Pacific Northwest National Laboratory Z.Q. Yu, Nanjing Normal University, China S.V.N.T. Kuchibhatla, Pacific Northwest National Laboratory C.M. Wang, Pacific Northwest National Laboratory O. Marina, Pacific Northwest National Laboratory W. Jiang, Pacific Northwest National Laboratory V. Shutthanandan, Pacific Northwest National Laboratory P. Nachimuthu, Pacific Northwest National Laboratory R. Devanathan, Pacific Northwest National Laboratory L.V. Saraf, Pacific Northwest National Laboratory S. Thevuthasan, Pacific Northwest National Laboratory |
| Correspondent: | Click to Email |
The development of electrolyte materials with high oxygen ion conductance at relatively low temperatures is essential to increase the efficiency and lifetime of electrochemical devices, such as solid oxide fuel cells (SOFC). Recently, there has been considerable interest in scandia stabilized zirconia (SSZ) since it shows high oxygen ionic conductance in comparison to commonly used ytrria stabilized zirconia (YSZ) in SOFCs. We have used oxygen plasma assisted molecular beam epitaxy (OPA-MBE) to synthesize high quality SSZ thin films on sapphire (0001) substrates and systematically investigated the conductivity as a function of temperature and Sc concentration. The epitaxial films have been characterized using various surface and bulk sensitive capabilities to determine their structure and composition. The ionic conductivity of SSZ depends not only on the dopant concentration, but also on the crystalline structure of the thin films. The optimum Sc dopant concentration for the highest conductivity was observed as 18 cation % in the temperature range of 500-900 °C. Conductivity appears to be significantly high in high quality cubic SZZ films in comparison to mixed phases of cubic and monoclinic. Molecular dynamics simulations of oxygen diffusion in cubic SZZ between 1125 and 2500 K show that the oxygen vacancy has no preference between Sc and Zr first neighbors, but the activation energy for O diffusion changes with Sc dopant concentration. Insights into the role of Sc dopant concentration on conductivity of SZZ obtained from experiments and simulations will be presented