Journal article
Evaluation of LSF based SOFC cathodes using cone-shaped electrodes and EIS
Seven compositions of (La1-xSrx)0.99FeO3-δ (x = 0, 0.05, 0.15, 0.25, 0.35, 0.50, 0.70) perovskites were synthesized using the glycine-nitrate method. The (La1-xSrx)0.99FeO3-δ compounds were characterized with powder X-ray diffraction, dilatometry, total conductivity and electrochemical impedance spectroscopy on cone-shaped electrodes using a Ce1.9Gd0.1O1.95 electrolyte.
Dilatometry shows that the thermal expansion coefficient of the (La1-xSrx)0.99FeO3-δ compounds increases with increasing strontium content. Total conductivity finds is maximum for LSF35. The activity of the (La1-xSrx)0.99FeO3-δ based perovskites towards the electrochemical reduction of oxygen was strongly dependent of the strontium content, the activity being highest for the composition (La0.85Sr0.15)0.99FeO3-δ.
The results indicates that Fe(III) is the catalytic active specie towards the electrochemical reduction of oxygen in a solid oxide fuel cell on (La1-xSrx)0.99FeO3-δ compounds. The results also show that oxide ion vacancies in the perovskite structure are important for the electrochemical reduction of oxygen.
However, a negative effect of defect ordering (Sr2+ and oxide ion vacancies) is strongly indicated for the strontium rich compounds. Segregation of SrO to the surface might also play a detrimental effect on the activity towards the oxygen reduction reaction.
Language: | English |
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Year: | 2020 |
Pages: | 115096 |
ISSN: | 18727689 and 01672738 |
Types: | Journal article |
DOI: | 10.1016/j.ssi.2019.115096 |
ORCIDs: | Kammer Hansen, Kent |