Manjula I. Nandasiri

Doctoral Dissertation Announcement

---

Candidate: Manjula I. Nandasiri

Degree of: Doctor of Philosophy

Department: Physics

Title: Engineered Interfaces and Nano-scale Thin Films for Solid Oxide Fuel Cell Electrolytes

Committee:
Dr. Asghar N. Kayani, Chair
Dr. John A. Tanis
Dr. Sung G. Chung
Dr. Muralidhar K. Ghantasala
Dr. S. Thevuthasan

Date: Thursday, February 21, 2013 4 p.m. to 6 p.m.
2202 Everett Tower

Abstract:
Solid state electrolytes with high oxygen ionic conductivity at low temperatures are required to develop cost effective and efficient solid oxide fuel cells. The study investigates the influence of engineered interfaces on the oxygen ionic conductivity of Samaria doped CeO2 (SDC) and Scandia stabilized ZrO2 (ScSZ) multilayer thin film electrolytes. The epitaxial SDC(111)/ScSZ(111) multilayer thin films are grown on high purity Al2O3(0001) substrates by oxygen plasma-assisted molecular beam epitaxy. The number of layers and thickness in the multilayered samples are optimized to get maximum oxygen ionic conductivity through the sample. The SDC/ScSZ multilayer thin films show significant enhancement in the oxygen ionic conductivity with respect to the single layer samples. The 8-layer SDC/ScSZ film exhibits the maximum oxygen ionic conductivity (0.885 S/cm at 600°C) with one order of magnitude enhancement in the temperature range of 500-800°C compared to single layer thin films.