Brinch-Larsen, Mathias1; Søgaard, Martin1; Hjelm, Johan2; Frandsen, Henrik Lund2
1 Mixed Conductors, Department of Energy Conversion and Storage, Technical University of Denmark2 Department of Energy Conversion and Storage, Technical University of Denmark3 Applied Electrochemistry, Department of Energy Conversion and Storage, Technical University of Denmark
Solid oxide fuel cell (SOFC) cathodes were prepared by impregnating the nitrates corresponding to SrTixFe1-xO3-δ (STF), x= 0; 0.1; 0.2; 0.3; 0.4 and 0.5, into a porous backbone of Ce 0.9Gd0.1O2-δ (CGO). STF was chosen as very high oxygen surface exchange rate, high ionic conductivity and electrochemical stability as a thin film electrode have been reported for these materials. XRD measurements showed a high degree of secondary phase formation in the infiltrate as well as reaction with the CGO backbone. Microstructural analysis showed that the STF infiltrate had formed a coating on the CGO backbone. All prepared electrodes were characterized as symmetric cells using impedance spectroscopy. Within the investigated series the infiltrate with x = 0.1 (STF10) showed the best performance with an area specific resistance (ASR) of ASR ≈ 6.4 Ω cm2 (STF10) at 600°C in air. The relatively poor performance is believed to originate from poor electronic conduction in the electrodes and possibly also reactions between Sr-containing compounds and CGO. To circumvent the low electronic conductivity, backbones of a composite cathode containing LaCo0.4Ni0.6O 3-δ (LCN60) and CGO were also tried infiltrated with STF. The ASR of the backbone was 8.7 Ω cm2 prior to infiltration and this decreased to 0.34 Ω cm2 after infiltration with STF10.
Ceramic Engineering and Science Proceedings, 2013, p. 1-12
Ceramic materials; Electric conductivity; Film preparation; Impregnation; Iron compounds; Solid oxide fuel cells (SOFC); Cathodes
Main Research Area:
Ceramic Engineering and Science Proceedings
36th International Conference on Advanced Ceramics and Composites, 2013