Ionic conductivity behavior by activated hopping conductivity (AHC) of barium aluminoborosilicate glass–ceramic system designed for SOFC sealing

• Published in: Journal of the European Ceramic Society Vol. 39; no. 10; pp. 3103 - 3111
• Main Authors: Da Silva, M.J., Pontuschka, W.M., Bartolomé, J.F., Jasinski, P., Karczewski, J., Reis, S.T.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-08-2019
• Subjects: Activated hopping conduction; Glass–ceramics; Impedance spectroscopy; Phase separation; Sealants; SOFC; Glass–ceramics; Activated hopping conduction; Impedance spectroscopy; Sealants; Phase separation; SOFC
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2019.03.027

Non-conducting BaO-B2O3-Al2O3-SiO2 parent glasses designed for solid oxide fuel cell (SOFC) sealing applications were prepared using the melt-quenching technique. The glass formation region was determined according to phase equilibrium relations and was found to be in the composition range 70BaO-(x)Al2O3-(10−x)B2O3-20SiO2 where 3.0 < x < 6.0 wt%. The conductivity values obtained conductivity ranged from 10−5 to 10−10 S/cm at temperatures between 600 and 850 °C. The batch compositions presented a threshold of dc conductivity near 70BaO wt% with a quasi linear behavior with the decrease of the BaO content. Different values of conduction activation energy were observed at temperatures above the glass transition temperature (Tg) (up to 700 °C), which were attributed to the thermal bond-breaking of non-bridging oxygen (NBO) defects. The experimental results of the electrochemical characterization by impedance spectroscopy of glass–ceramic interfaces with yttria-stabilized zirconia (YSZ) acting as solid ionic conductor electrolyte are presented and discussed.