The role of dopant segregation on the oxygen vacancy distribution and oxygen diffusion in CeO2 grain boundaries

Adam Symington, Marco Molinari, Joel Statham, Ji Wu, Stephen Charles Parker

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8 Citations (Scopus)


An important challenge when attempting to identify the role of microstructure and the effect of dopant concentration on the properties of energy materials is to distinguish the behaviour of each grain boundary. In this paper we describe our recent work using atomistic simulations to investigate the structure, composition and oxygen transport of gadolinium doped cerium dioxide tilt grain boundaries. We find that energy minimisation can be systematically employed to screen grain boundary structures and dopant segregation. When dopants are distributed equally across grains, molecular dynamics simulations reveal oxygen vacancies reside near dopants, resulting in higher oxygen diffusivity. Once the dopants accumulate at the grain boundaries these grain boundaries become saturated with oxygen vacancies. We see fast oxygen diffusion within the grain boundary plane, although the depletion layer, as shown via the electrostatic potential appears to block transport across the grain boundary. However, this is highly dependent on the grain boundary structure as we find striking differences of the potential and the segregation behaviour between each of interface studied.
Original languageEnglish
Number of pages15
JournalJournal of Physics: Energy
Issue number4
Early online date11 Jun 2019
Publication statusPublished - 20 Sep 2019


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