Evaluation of La sub(0.3)Sr sub(0.7)Ti sub(1-x)Co sub(x)O sub(3) as a potential cathode material for solid oxide fuel cells

Perovskites La sub(0.3)Sr sub(0.7)Ti sub(1-x)Co sub(x)O sub(3) (LSTCs, x= 0.3-0.6) are systematically evaluated as potential cathode materials for solid oxide fuel cells. The effects of Co substitution for Ti on structural characteristics, thermal expansion coefficients (TECs), electrical conductivi...

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Bibliographic Details
Published in:Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2014-06, Vol.2 (26), p.10290-10299
Main Authors: Du, Zhihong, Zhao, Hailei, Shen, Yongna, Wang, Lu, Fang, Mengya, Swierczek, Konrad, Zheng, Kun
Format: Article
Language:English
Subjects:
Cathodes
Electrical resistivity
Electrolytes
Electrolytic cells
Mathematical analysis
Resistivity
Solid oxide fuel cells
Titanium
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Summary:Perovskites La sub(0.3)Sr sub(0.7)Ti sub(1-x)Co sub(x)O sub(3) (LSTCs, x= 0.3-0.6) are systematically evaluated as potential cathode materials for solid oxide fuel cells. The effects of Co substitution for Ti on structural characteristics, thermal expansion coefficients (TECs), electrical conductivity, and electrochemical performance are investigated. All of the synthesized LSTCs exhibit a cubic structure. With Rietveld refinement on the high-temperature X-ray diffraction data, the TECs of LSTCs are calculated to be 20-26 10 super(-6) K super(-1). LSTC shows good thermal cycling stability and is chemically compatible with the LSGM electrolyte below 1250 degree C. The substitution of Co for Ti increases significantly the electrical conductivity of LSTC. The role of doping on the conduction behavior is discussed based on defect chemistry theory and first principles calculation. The electrochemical performances of LSTC are remarkably improved with Co substitution. The area specific resistance of sample La sub(0.3)Sr sub(0.7)Ti sub(0.4)Co sub(0.6)O sub(3) on the La sub(0.8)Sr sub(0.2)Ga sub(0.8)Mg sub(0.2)O sub(3- delta ) (LSGM) electrolyte in symmetrical cells is 0.0145, 0.0233, 0.0409, 0.0930 Omega cm super(2) at 850, 800, 750 and 700 degree C, respectively, and the maximum power density of the LSGM electrolyte (400 mu m)-supported single cell with the Ni-GDC anode, LDC buffer layer and LSTC cathode reaches 464.5, 648, and 775 mW cm super(-2) at 850 degree C for x= 0.3, 0.45, and 0.6, respectively. All these results suggest that LSTC are promising candidate cathode materials for SOFCs.
ISSN:2050-7488
2050-7496
DOI:10.1039/c4ta00658e