Influence of Lithium Oxide Addition on the Sintering Behavior and Electrical Conductivity of Gadolinia Doped Ceria

• Published in: Journal of materials science & technology Vol. 27; no. 5; pp. 460 - 464
• Main Authors: Han, Minfang, Liu, Ze, Zhou, Su, Yu, Lian
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 2011
• Subjects: Electrical conductivity; Gadolinia doped ceria; Sintering additive; 中温固体氧化物燃料电池; 扫描电子显微镜; 掺杂; 氧化铈; 氧化锂; 烧结行为; 电化学阻抗谱; 高电导率; Sintering additive; Gadolinia doped ceria; Electrical conductivity
• ISSN: 1005-0302; 1941-1162
• DOI: 10.1016/s1005-0302(11)60091-1

Ceria-based electrolytes have been widely researched in intermediate-temperature solid oxide fuel cell （SOFC）, which might be operated at 500-600℃. Sintering behavior with lithium oxide as sintering additive and electrical conductivity of gadolinia doped ceria （GdonCe0.902-σ, GDC10） electrolyte was studied in this paper by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and electrochemical impedance spectroscopy （EIS）. As the results,, the fully dense GDC10 electrolytes are obtained at a low temperature of 800℃ with 2.5 mol% Li20 as sintering additive （called 5LiGDCS00）. During sintering process, lithium oxides adsorbed by around GDC10 surface help to sinter at 800~C and are kept at the grain boundary of GDC10 in the end. The fine grains of 100-400 nm and high electrical conductivity of 0.014 S/cm at 600~C in 5LiGDC800 were achieved, which contributed to the lower sintering temperature and enhanced grain boundary conductivity, respectively. Lithium, staying at grain boundary, reduces the depletion of oxygen vacancies in the space charge layers and increases the oxygen vacancy concentration in the grain boundary, which leads to improve the total electrical conductivity of 5LiGDC800.