Effect of Ceria Content of CeScSZ Powder on the Phase Stability and Electrical Conductivity of SOFC Electrolyte

Solid oxide fuel cell (SOFC) is attracting more attention in recent years for its lower pollution emission and high energy convert efficiency. The SOFC is conventionally operated at high temperatures between 900 and 1000 °C, because of the low ionic conductivity of YSZ below 800 °C. ScSZ-based electrolyte is one of the candidate materials for IT-SOFCs because of their higher ionic conductivities compared to any other zirconia electrolytes. In general, it is reported that 1Ce10ScSZ composition is available as ScSZ-based electrolyte of SOFC [1].

 In this paper, CeScSZ powders with ceria-doped content were synthesized by co-precipitation process. The crystal lattice parameter and XRD peak pattern of powders were investigated with the increase of calcination temperature and the change of ceria-doped content at a certain calcination temperature. Ionic conductivities of the CeScSZ powders were also studied at the range of 500 ~ 900 °C. In here, the XRD peaks of cubic structure were found only on the ceria-doped powders more than 1 mole% even at the calcination temperature of 1500 °C. Meanwhile, the behaviour of ionic conductivities showed little different characteristics from the XRD pattern, namely, 1 mole% ceria-doped 10ScSZ powder showed the highest conductivity. Therefore, electrolyte film was fabricated by using the synthesized 1Ce10ScSZ powder and single cell of SOFC with anode-supported electrolyte was fabricated by  tape casting and co-sintering process. As a result, the SOFC cell showed power density of 1.2 W/cm² at 2 A/cm², 800 °C with low ohmic resistance of under 0.1 W·cm².   

References

[1] Ju Hee Kang, Young Mi Kim, Ho-Sung Kim, Moo Sung Lee, Jae Hyuk Jang, Jin-Hun Jo “Fabrication characteristics of SOFC single cell using nanocrystalline 1Ce10ScSZ electrolyte powder prepared by co-precipitation process,” J. Full Cell and Technology, 2012, Vol 9, pp. 011015.