A strategy for improving the sinterability and electrochemical properties of ceria-based LT-SOFCs using bismuth oxide additive

Influences of Bi0.75Y0.25O1.5 addition on the microstructure and ionic conductivity of Ce0.8Y0.2O1.9 ceramics

“…One of the focus research issues on SOFC is to develop outstanding electrolytes with higher ionic conductivity in a lower operation temperature range. [5][6][7] Among several potential candidate electrolytes for SOFC, the doped ceria shows many remarkable advantages compared with the traditional yttria-stabilized zirconia (Zr 0.92 Y 0.08 O 1.96 , 8YSZ) especially in the intermediate operation temperature range of 300°C-700°C. However, the application of the CeO 2 -based electrolyte in SOFC is restricted because of its non-negligible electron conduction in reducing atmosphere as well as its higher sintering temperature (a sintering temperature of about 1400°C is required for a relative density of 95%~98%).…”

“…Considering the fact that the doped-Bi 2 O 3 was an excellent oxygen ion conductor, some doped δ-Bi 2 O 3 additives had also been introduced into CeO 2 or ZrO 2 -based ceramics to increase the ionic conductivity by 5-10 times and improve the sintering performance. 5,15,16 For example, Jaiswal et al 17 (CLO). As a result, the ionic conductivity of CLO at 600°C could reach 1.41 × 10 −2 S/cm by adding 0.5 wt% ESB, which was nearly an order of magnitude higher than that of the pure CLO (1.99 × 10 −3 S/cm) at the same temperature.…”

“…In general, the sequence of the ionic conductivity for these solid electrolytes with cubic fluorite structure is as follows: Bi 2 O 3 ‐based>CeO 2 ‐based>ZrO 2 ‐based ceramic. One of the focus research issues on SOFC is to develop outstanding electrolytes with higher ionic conductivity in a lower operation temperature range 5–7 . Among several potential candidate electrolytes for SOFC, the doped ceria shows many remarkable advantages compared with the traditional yttria‐stabilized zirconia (Zr 0.92 Y 0.08 O 1.96 , 8YSZ) especially in the intermediate operation temperature range of 300°C–700°C.…”

“…Considering the fact that the doped‐Bi 2 O 3 was an excellent oxygen ion conductor, some doped δ‐Bi 2 O 3 additives had also been introduced into CeO 2 or ZrO 2 ‐based ceramics to increase the ionic conductivity by 5–10 times and improve the sintering performance 5,15,16 . For example, Jaiswal et al 17 discovered that Er 2 O 3 ‐stabilized Bi 2 O 3 (Bi 0.8 Er 0.2 O 1.5 , ESB) could not only improve the sintering performance, but also clean the silicon phase in the grain boundary of Ce 0.85 La 0.15 O 1.925 (CLO).…”

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A second phase of Y 2 O 3 -stabilized Bi 2 O 3 (Bi 0.75 Y 0.25 O 1.5 ,YSB) is introduced into Y 2 O 3 -doped CeO 2 (Ce 0.8 Y 0.2 O 1.9 ,YDC) as a sintering additive and the composite ceramics of 5,10,20,30, 40 wt%) are prepared through sintering at 1100°C for 6 h in air atmosphere. The YDC-xYSB ceramics are composed of both YDC and YSB with cubic fluorite structure, and no other impurity phases are detected in XRD patterns.

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