Microstructure — ionic conductivity relationships in ceria-gadolinia electrolytes

Influence of impurity-vacancy disorder on characteristics of gadolinium-doped ceria oxide: Molecular dynamics study

“…Grain boundaries influence on the conductivity decreases with increasing temperature, and according to Zhang [19] total conductivity (marked as "(exp) Zhang, total" in Fig.5) is approximately equal to the bulk conductivity. In [17] it is shown that when a size of the grain is decreased the grain boundary resistance decreases. Total conductivity "Ivanov, total, submicron grain" [20] of the ceramics, which has a grain size of about 250nm, is almost identical in magnitude to the bulk conductivity.…”

“…The calculated activation energies for the different GdD for the given potentials set are practically the same, which again suggests a weak GdD influence on the macro parameters. The experimental activation energies for the bulk conductivity (AvilaParedes, Christie, Zhang) and for the total conductivity of submicron ceramic In [17] Christie gives estimation of the diffusion activation energy equal to 0.9eV for all the studied temperature range (6 points in the range of 250-500 ˚C)…”

“…Experimental data on the bulk conductivity of Ce 0.8 Gd 0.2 O 1.9 crystals were taken from Avila-Paredes [15], Mogensen [16], Christie [17] and Zhang [18]. Grain boundaries influence on the conductivity decreases with increasing temperature, and according to Zhang [19] total conductivity (marked as "(exp) Zhang, total" in Fig.5) is approximately equal to the bulk conductivity.…”

“…It were obtained with the samples with X = 0.1, and bring, in particular, to demonstrate the correctness of the Nernst-Einstein relation (1) using. The depth of the oxygen isotope profile is 0.07cm, the average grain size for typical CGO ceramics can be estimated as 10μm = 0.01cm (see for example [17]) -so, it can be assumed that in the SIMS experiments the total effective diffusion was measured (in the bulk and in the grain boundary), and it should be compared with the total conductivity. Data on the total conductivity for CGO ceramics with X=0.1 were obtained from [15] and are marked on the Fig.5 as "Avila-Paredes, X=0.1, total".…”

Preparation and characterization of Ce0.85La0.15 − xSrxO{2 − (0.075 + x / 2)} solid electrolytes for intermediate temperature solid oxide fuel cells

“…Use of a simple capacitor is not sufficient to model the electrical response of these materials due to microstructural inhomogenieties in the sample. A constant phase element (CPE) is, therefore, used to fit the data [30]. CPE is equivalent to a distribution of capacitors in parallel.…”