J. Mater. Sci. Technol. ›› 2011, Vol. 27 ›› Issue (5): 460-464.

• Reviews • 上一篇    下一篇

Influence of lithium oxide addition on the sintering behavior and electrical conductivity of gadolinia doped ceria

韩敏芳1,刘泽2,3,周肃2,3,于立安2,3   

  1. 1. 中国矿业大学（北京），化学与环境工程学院
    2.
    3. 中国矿业大学（北京）
  • 收稿日期:2010-09-26 修回日期:2010-12-05 出版日期:2011-05-28 发布日期:2011-05-28
  • 通讯作者: 韩敏芳
  • 基金资助:

    National Science Council;National Natural Science Foundation of China

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

Minfang Han, Ze Liu, Su Zhou, Lian Yu   

  1. Union Research Center of Fuel Cell, School of Chemical & Environment Engineering, University of Mining & Technology (CUMTB), Beijing 100083, China
  • Received:2010-09-26 Revised:2010-12-05 Online:2011-05-28 Published:2011-05-28
  • Contact: Minfang Han
  • Supported by:

    the National Natural Science Foundation of China (Grant No. 50730004), and the Ministry of Science and Technology of the People's Republic of China (No. 2009DFA6136)

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摘要： Ceria-based electrolytes have been widely researched in intermediate- temperature solid oxide fuel cell (SOFC), which might be operated at 500~600°C. Sintering behavior with lithium oxide as sintering additive and electrical conductivity of gadolinia doped ceria (Gd0.1Ce0.9O2-δ, GDC10) electrolyte was studied in this paper by XRD, SEM and EIS. As the results, the fully dense GDC10 electrolytes are obtained at a low temperature of 800°C with 2.5mol% Li2O as sintering additive (called as 5LiGDC800). During sintering process, lithium oxides adsorbed 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 0.014S/cm at 600°C in 5LiGDC800 are 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.

Abstract: Ceria-based electrolytes have been widely researched in intermediate-temperature solid oxide fuel cell (SOFC), which might be operated at 500−600°C. Sintering behavior with lithium oxide as sintering additive and electrical conductivity of gadolinia doped ceria (Gd0.1Ce0.9O2-δ, 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°C with 2.5 mol% Li2O as sintering additive (called 5LiGDC800). 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.

Key words: Gadolinia doped ceria, Sintering additive, Electrical conductivity