A computational investigation of structure and properties of nanostructured material based on Cerium Dioxide (CeO2)

Abstract

Fluorite-structured ceramic materials based on ceria are have been intensively studied because of their potential to substitute zirconia in solid oxide fuel cells. The most relevant aspect for their application as solid electrolyte is the oxygen ion conductivity. In polycrystalline materials oxygen transport is largely controlled by phenomena occurring at the grain boundaries. The present PhD research work was focused on the computer simulation of structure, defect distribution and transport phenomena in gadolinium doped ceria. Static lattice simulations were used to investigate the structure of the bulk material as well as surfaces and grain boundaries. It was also employed for the calculation of the grain boundary enthalpies of segregation for the major lattice defects, i.e. oxygen vacancies and gadolinium onto cerium sites. Molecular dynamics techniques were on the other hand used to explore transport phenomena, with particular emphasis on the oxygen diffusion.