(Invited) Probing Oxide Ion Transport in Fluorite and Perovskite Oxides for Solid Oxide Fuel Cells

Abstract

Oxygen surface exchange reactions occurring at the solid cathode surface, and subsequent incorporation and transport of oxygen species across heterostructures strongly affect the performance of solid oxide fuel cells (SOFCs). Using isotopic exchange in conjunction with secondary ion mass spectroscopy (SIMS) depth profile analysis, we examined some technologically relevant fluorite and perovskite thin film oxides commonly utilized as component materials for intermediate-temperature SOFCs. In general, nanograined thin films exhibited improved oxygen surface exchange kinetics as compared to quasi-single-crystalline thin films, indicating enhancement of oxygen incorporation facilitated via highly dense grain boundaries. Furthermore, results indicated strong dependence of oxygen surface exchange properties on crystalline orientation. These results demonstrate the versatility of the technique to further our understanding of oxide ion transport occurring across various heterostructures and heterointerfaces, which hopefully would lead towards envisaging new structures and interfaces for high-performance SOFCs.