Evaluation of the Microstructure and the Electrochemical Properties of Ce0.8(1−x)Gd0.2(1−x)CuxO[1.9(1−x)+x] Electrolytes for IT-SOFCs

Abstract

<jats:p>The influence of copper addition (0.5–2 mol%) on the crystal structure, densification microstructure, and electrochemical properties of Ce0.8Gd0.2O1.9 synthesized in a one-step sol–gel combustion synthesis route has been studied. It has been found that Cu is very active as sintering aids, with a significative reduction of GDC firing temperature. A reduction of 500 °C with a small amount of copper (0.5 mol%) was observed achieving dense bodies with considerable ionic conductivities. Rietveld refined was used to investigate the crystal structure while relative density and microstructural examination were performed in the sintering temperature range of 1000–1200 °C after dilatometer analysis. High dense bodies were fabricated at the lowest sintering temperature, which promotes the formation of Ce0.8(1−x)Gd0.2(1−x)CuxO[1.9(1−x)+x] solid solution and the absence of secondary phase Cu-rich or the segregation or copper at the grain boundary. As compared to the pure GDC an improvement of total conductivity was achieved with a maximum for the highest copper content of 2.23·10−3–9.19·10−2 S cm−1 in the temperature range of 200–800 °C.</jats:p>

Recent Advances and Challenges in Thin-Film Fabrication Techniques for Low-Temperature Solid Oxide Fuel Cells

“…However, the addition of sintering additives can decrease the conductivity of the electrolyte, especially in the presence of SiO 2 impurities by increasing the grain boundary resistance [266]. For example, it was reported that cobalt oxide and copper oxide are useful additives in promoting the sinterability of ceria solid solutions (i.e., GDC); however, most of the added cobalt and copper ions were found to segregate at the grain boundaries [267,268]. When studying the microstructure and conductivity of doped ceria, background impurities, such as SiO 2 , are of major concern.…”

Development and characterization of solid oxide electrolysis cells based on zirconia and ceria based electrolyte for hydrogen production from steam

“…It should be noted that not only sintering aid can improve the sinterability of electrolyte but the use of nanometer-or submicronelectrolyte starting-powders derived from wet synthesis, e.g. sol-gel [123], can facilitate the growth of electrolyte densification [124]. However, at sintering lower than 1350°C, the grain boundaries were not obviously observed on 1Bi10SCGZ electrolyte.…”