Origin of Space Charge in Grain Boundaries of Proton-Conducting BaZrO3
Artikel i vetenskaplig tidskrift, 2013

Segregation energies of oxygen vacancies and protons near three symmetric tilt grain boundaries (GBs) in BaZrO3 are determined using density functional theory. Two of the GBs have the [-110] direction as tilt axis whith a (111) or (112) plane as GB plane, while the third has the [001] direction as tilt axis and a (210) plane as GB plane. Both defects are found to segregate to all three GBs, with vacancy segregation energies of -0.5 and -1.5 eV and proton segregation energies of about -0.8 eV. The effects of the calculated segregation energies on defect concentrations and electrostatic potential in the GB region are investigated using a thermodynamic space charge model. An increased concentration of defects is seen in all GBs, giving electrostatic potential barriers around 0.6 V at 400-900 K. Protons are found to give important contributions to the space charge in all three GBs.

Space Charge Theory

Proton Conductors

Conducting Materials

Grain Boundaries

Defect Segregation

Density Functional Calculations

Författare

Edit Ahlberg Helgee

Chalmers, Teknisk fysik, Material- och ytteori

Anders Lindman

Chalmers, Teknisk fysik, Material- och ytteori

Göran Wahnström

Chalmers, Teknisk fysik, Material- och ytteori

Fuel Cells

1615-6846 (ISSN) 1615-6854 (eISSN)

Vol. 13 19-28

Drivkrafter

Hållbar utveckling

Styrkeområden

Energi

Materialvetenskap

Infrastruktur

C3SE (Chalmers Centre for Computational Science and Engineering)

Ämneskategorier

Den kondenserade materiens fysik

DOI

10.1002/fuce.201200071