| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1288397 | Journal of Power Sources | 2012 | 7 Pages |
In the present work, the microwave heating (MH) route is used to prepare and sinter dysprosium-doped ceria (DDC) nanopowder, Ce(1−x)DyxO2−x/2 (x = 0.05–0.25 at.%), and the results are compared with the same composition obtained by conventional heating (CH). The results show that the as-synthesized powders are pure oxides with high crystallinity. The average crystallite size of the MH-DDC samples is approximately 22 nm, while the CH-DDC sample size is approximately 29 nm. The sinterability of the MH samples is greater than that of the CH samples. Microwave sintering produces high-density MH-DDC pellets with fine and almost homogeneous grain-growth and a grain size of 400 nm, while the conventionally densified pellets have non-uniform grains range in size from 1100 to 1400 nm. The electrical properties of the sintered pellets were investigated by impedance spectroscopy. The ionic conductivity of the MH-DDC15 pellet sintered by microwave at 1050 °C for 1 h was determined to be σ550 °C = 7.42 × 10−2 S cm−1, with an activation energy of Ea = 0.86 eV. The pellets that were conventionally sintered at 1300 °C for 5 h were found to have ionic conductivity of σ550 °C = 9.79 × 10−3 S cm−1, with Ea = 1.05 eV. The correlations between the grain, grain boundary relaxation and ion transport mechanism in nanocrystalline electrolyte materials are discussed.
Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Microwave heating route for synthesis and sintering to Dy-doped ceria. ► Homogeneous grain-growth with air-tight density is achieved at much lower temperature 1050 °C for 1 h sintering in microwave. ► Conventional heating requires 5 h sintering at 1400 °C for gas-tight compactness. ► Processing routes strongly influence on sintering behavior and electrical properties. ► Microwave-assisted processing route has potential to develop nanocrystalline doped ceria powders as electrolytes for IT-SOFCs.
