TY  - JOUR
AU  - Parras, Jana P.
AU  - Cao, Chen
AU  - Ma, Zheng
AU  - Mücke, Robert
AU  - Jin, Lei
AU  - Dunin‐Borkowski, Rafal
AU  - Guillon, Olivier
AU  - De Souza, Roger A.
TI  - The grain‐boundary resistance of CeO 2 ceramics: A combined microscopy‐spectroscopy‐simulation study of a dilute solution
JO  - Journal of the American Ceramic Society
VL  - 103
IS  - 3
SN  - 1551-2916
CY  - Westerville, Ohio
PB  - Soc.
M1  - FZJ-2020-02950
SP  - 1755 - 1764
PY  - 2020
AB  - Weakly acceptor‐doped ceria ceramics were characterized structurally and compositionally with advanced transmission electron microscopy (TEM) techniques and electrically with electrochemical impedance spectroscopy (EIS). The grain boundaries studied with TEM were found to be free of second phases. The impedance spectra, acquired in the range 703 ≤ T/K ≤ 893 in air, showed several arcs that were analyzed in terms of bulk, grain‐boundary, and electrode responses. We ascribed the grain‐boundary resistance to the presence of space‐charge layers. Continuum‐level simulations were used to calculate charge‐carrier distributions (of acceptor cations, oxygen vacancies, and electrons) in these space‐charge layers. The acceptor cations were assumed to be mobile at high (sintering) temperatures but immobile at the temperatures of the EIS measurements. Space‐charge formation was assumed to be driven by the segregation of oxygen vacancies to the grain‐boundary core. Comparisons of data from the simulations and from the EIS measurements yielded space‐charge potentials and the segregation energy of vacancies to the grain‐boundary core. The space‐charge potentials from the simulations are compared with values obtained by applying the standard, analytical (Mott–Schottky and Gouy–Chapman) expressions. The importance of modelling space‐charge layers from the thermodynamic level is demonstrated.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000492529100001
DO  - DOI:10.1111/jace.16843
UR  - https://juser.fz-juelich.de/record/878612
ER  -