Ionic conductivities, sintering temperatures and microstructures of bulk ceramic CeO2 doped with Y2O3

Stable High Conductivity Bilayered Electrolytes for Low Temperature Solid Oxide Fuel Cells

“…Activation energies and pre-exponential factors for SDC and SDC\ESB electrolytes are listed in Table 2-2 and they are in good agreement with Tian and Chan [22], and Wang et al's results [31]. An inspection of Table 2-2 shows that activation energies and pre-exponential factors obtained by the capacitance method [19 -23] were larger than those obtained by the geometric method [19 -23].…”

“…A similar difference between the two methods was observed by Tian and Chan [22]. The difference between the values of the activation energy and pre-exponential terms, obtained from the capacitance and geometric methods, most likely arises from the inaccuracy in the assumed values of grain size and grain-boundary thickness used in the geometric method [19 -23].…”

“…This is neither a trivial nor an unambiguous operation, however, and there are currently two prevailing schools of thought that have produced two distinct methodologies namely: the geometric method and the capacitance method. Additional information may be obtained from recent reviews on grain-boundary conductivity and microstructure relations by Steele [19], Virkar et al [20], Hong et al [21], Tian and Chan [22], and Gerhardt and Nowick [23]. …”

The Effect of Co and Zn Addition on Densification and Electrical Properties of Ceria-Based Nanopowders

“…The bulk (σ b ) and total (σ t ) electrical conductivities were calculated from the corresponding (bulk and total=bulk+grain boundary) R values taking into account the sample geometry. The grain boundary conductivity was calculated assuming estimates for the grain boundary thickness and grain size, to calculate the microscopic grain boundary conductivity can be calculated as usual 24 . Figure 8 depicts Arrhenius plots of the bulk and microscopic grain boundary electrical conductivities measured in air for specimens sintered 1200-1000 °C/10h.…”

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

“…This is because for small grain size, i.e., larger grain boundary area, the finite amount of impurity contained in the sample is not sufficient to form a continuous and uniform glassy phase layer along grain boundaries. This leaves the remaining grain boundary area for clean grain to grain contact [38]. Therefore, the transport of O 2− ions becomes faster across the grains through clean grain boundaries.…”