PNNL

Abstract

This chapter describes the results from a project that aimed to develop an understanding of oxygen ionic transport processes in oxide nanostructured materials that may enable the design of new types of electrolyte materials for electrochemical device applications with enhanced ionic conductivity that function well at low temperatures. Increased ionic transport at low temperatures would simply allow the use of a wide range of lower-cost materials for electrochemical devices. Interface-controlled nucleation and growth of two- and three-dimensional, nanostructured materials show unique physical, chemical and electronic properties that are different from bulk materials due to quantum confinement and other effects occurring at the nanoscale. Atomic and ionic transport, which is crucial for many technological applications including catalysis and fuel-cell technology, is also expected to be enhanced in nanostructured materials due to effects related to size, electronic structure, space charge and multiple interface pathways. We have investigated the fundamental scientific issues associated with oxygen ionic transport properties of multilayer, single- and poly-crystalline nano-oxide film structures on suitable substrates. We have taken advantage of our ability to grow and characterize single-crystal, pure and doped multilayer, nanoscale materials, using state-of-the-art capabilities at the Environmental Molecular Sciences Laboratory (EMSL). Detail description of the results from the investigations of thin films with nanodomains, with interfaces parallel to the substrate surfaces and with interfaces perpendicular to the substrate surfaces is discussed.