Assessment of processing route on the performance of ceria‐based composites. (2nd February 2021)

• Record Type: Journal Article
• Authors: Grilo, João P. F.; Macedo, Daniel A.; Nascimento, Rubens M.; Marques, Fernando M. B.
• Other Names: Atabani Abdulaziz E. guestEditor.
• Is Part Of: International journal of energy research. Volume 45:Number 6(2021)
• Page Start: 9069
• Page End: 9082
• Publication Date: 2021-02-02
• Subjects: alkali metal carbonates -- ceria -- composites -- electronic conductivity -- percolation; Power resources -- Periodicals; Power (Mechanics) -- Periodicals; Power resources -- Research -- Periodicals; 621.042
• DOI: 10.1002/er.6438
• Languages: English
• ISSNs: 0363-907X

Abstract

Summary: Gd‐doped ceria (GDC)‐based composites, including a eutectic mixture of lithium and sodium carbonate (NLC) as second phase, were prepared using several processing routes, namely chemical synthesis, co‐firing of both phases, or impregnation of a presintered porous matrix. LiAlO2 ‐based composites were also prepared and used as reference. The structural, microstructural, and electrical properties (impedance spectroscopy in air, up to 700°C) of these materials were assessed in detail. A limited set of compositions was also used in measurements of total electrical conductivity at different oxygen partial pressures (from 0.21 to <10 −25 atm), in the 600°C to 700°C range. The results obtained confirmed the enormous impact of the processing route on the percolation of the ceramic phase. In the exploited range of operating conditions, GDC‐NLC composites prepared by infiltration of molten carbonates within a mechanically robust ceramic matrix exhibit a high total ionic conductivity strongly influenced by the contribution of the molten salt while the ceramic phase is decisive in the appearance of a significant component of electronic conductivity under reducing conditions. Abstract : Gd‐doped ceria (GDC) and (Na0.48 Li0.52 )2 CO3 eutectic (NLC) composites via several processing routes. Higher ionic conductivity of GDC‐NLC composites using chemical and impregnation routes with respect to conventional route. Electrical conductivity as a function of temperature and oxygen partial pressure. Identification of the onset of electronic conductivity.