Preparation and properties of dense Ce0.9Gd0.1O2−δ ceramics for use as electrolytes in IT-SOFCs

Electrical properties of samaria-doped ceria electrolytes from highly active powders

“…sintered at low-temperatures. Zhang et al [38] confirmed that the dissolution of Gd 2 O 3 into CeO 2 was not completed when the ceramics were sintered at temperatures below 1600 • C using powders derived from solid state reaction. In this work, gi for samples sintered at 900 • C was close to those sintered at temperatures above 1300 • C, suggesting that Sm 3+ was uniformly dissolved in the ceria solid solution at temperature as low as 900 • C. This further indicates high compositional homogeneity as well as very high sinterability of the precursor powders.…”

Low temperature fabrication of dense gadolinia-doped ceria electrolyte with enhanced electrical conductivity

“…When the pellet is heated up to ∼1200 o C, the relative density starts to decrease. In fact, this interesting phenomenon of anti-densification has been reported by Zhang et al [14], who examined the effect of calcination temperatures on the pellets' densification behaviors and found out volume expansion in the sintering temperature range of ~1250-1400 o C when lower calcining temperatures (≤ 700 o C )…”

“…They pointed out it may be caused by the partial loss of lattice oxygen atoms and the subsequent reduction of Ce 4+ to Ce 3+ , resulting in lattice expansion and macroscopic volume increase due to the larger radius of Ce 3+ (0.105 nm) than Ce 4+ (0.097 nm). Especially, with regard to ultrafine nanocrystalline powders, the lower temperature the powder is calcined, the lower temperature the anti-densification phenomenon occurs [14]. Hence, in this paper, taking into account the fact that the synthesized powder originally possesses high sintering activity and that it was calcined under a relative comfortable condition (400 o C for 2 h), it is reasonable for the sample having an anti-densification onset temperature of ~1200 o C. By contrast with this powder, the powder synthesized by NH 4 OH coprecipitation and then calcined at 600 o C for 2 h didn't show any anti-densification behaviors during similar measurement [22], and this comparison fully illustrates the dependence of the sintered ceria-based electrolyte's anti-densification phenomenon on its original powder's quality.…”

“…Ceria solid solution is widely recognized as a promising electrolyte for IT-SOFCs due to higher oxygen ionic conductivity and better chemical compatibility to electrode materials than conventional yttria stabilized zirconia (YSZ) [6][7][8][9][10][11][12][13]. However, one of the main difficulties encountered in application about ceria-based materials is to obtain densified electrolytes at low temperatures, which usually need to expose to high temperatures over 1600 o C when solid-state reactions are applied, leading to electrochemical performance degradation [14]. Fortunately, nanometric powder preparation has shown to be effective for low-temperature densification of ceria solid solution, which is of significance for cost-effective fabrication of IT-SOFCs [15][16][17].…”

Formation of samarium doped ceria thin films

“…Different types of electrolyte materials could be used, such as lanthanum gallate ceramic including lanthanum strontium gallium magnesium, bismuth yttrium oxide, barium cerate, strontium cerate, zirconium oxide or cerium oxide stabilized by rare earth oxides, etc. [1][2][3][4][5][6]. In recent years doped ceria, as a potential substitute for stabilized zirconia electrolyte, has increasingly attracted more interest for its higher conductivity in the field of intermediate temperature solid oxide fuel cells (ITSOFCs) [7].…”