resumo
Molten carbonate remained a topic of intense research in electrochemical sciences, particularly where it co-exists with ceramic phases in composites. Various models and assumptions were developed to explain the behavior of carbonate. In fact, most explanations, such as superionic diffusion along the interface, are yet challenged in research, which needs right justification or overwriting the story to nullify those claims. Here, we attempt to develop our understanding of carbonate conductivity based on the well-established concept of changing ionic mobility in vicinity of ceramic surface, which depends on extension of interface (area) among ceramic and molten phases and surface defect conc. and molten carbonate wettability of ceramic. Therefore, to discuss the behavior of carbonate, in present work, the solid/molten interface area was expanded in Ce0.9Gd0.1O1.95(CGO)NaLiCO3(NLC), where NLC varied from 3 to 40 vol%. In initial experiments, the CGO matrices of fixed 30 vol% porosity were impregnated at 650-800 degrees C to find the optimum temperature. Then, all CGO matrices of 10-40 vol % porosities were impregnated at optimum temperature. The SEM micrographs showed NLC impregnation changes the microstructure of composites from partially soaked CGO grains to the grains suspended in pool of NLC melt. The composite conductivity measurements were performed at temperature starting from 200 degrees C, where only ceramic phase is active, to 700 degrees. As well, on basis of matching activation energies and eutectic points, three distinct conductivity regions were recognized in Arrhenius.
palavras-chave
ELECTRICAL-CONDUCTIVITY; IONIC-CONDUCTIVITY; DOPED CERIA; OXIDE; PHASE; POWDER; SINGLE
categoria
Electrochemistry
autores
Jamale, AP; Nikte, SS
nossos autores
Atul Prabhakar Jamale
Investigador JúniorProjectos
CICECO - Aveiro Institute of Materials (UIDB/50011/2020)
CICECO - Aveiro Institute of Materials (UIDP/50011/2020)
Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)
agradecimentos
This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020, financed by national funds through the FCT/MCTES (PIDDAC). Specific support (AJ) provided by national funds (OE), through FCT, IP, in the scope of the framework contract foreseen in the numbers 4, 5, and 6 of the article 23 of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19.