Evaluation of the Perovskite (La0.8Sr0.2)0.95Fe0.8Ni0.2O3–δ as SOFC Cathode

✍ Scribed by S. B. C. Duval; T. Graule; P. Holtappels; J. P. Ouweltjes; G. Rietveld

• Publisher: John Wiley and Sons
• Year: 2009
• Tongue: English
• Weight: 316 KB
• Volume: 9
• Category: Article
• ISSN: 1615-6846
• DOI: 10.1002/fuce.200900154

✦ Synopsis

The evaluation of new alternative materials for SOFC cathodes comprises numerous steps, starting from basic materials properties, such as conductivity, physical and chemical compatibility with adjacent materials during fabrication and operating conditions, up to electrochemical performance tests. The perovskite system (La 1-x Sr x ) y Fe 1-z Ni z O 3-d has been proposed based on favourable electrical properties and mixed ionic electronic conductivity [1-3] compared to La-Sr-Mn perovskites. Electrochemical tests on button sized anode supported cells (active area 1-1.7 cm 2 ) [4] combined with the given cathode composition reached a power density of 0.5 and 0.3 W cm -2 at 750 and 650 °C, respectively. A more detailed study [5] of the single cathode performance in the La 0.7 Sr 0.3 Fe 1-x Ni x O 3-d system confirmed a slightly negative influence of Ni addition on the oxygen reduction activity compared to Ni-free La-Sr ferrite. However, area specific resistances (ASR) of 0.12 and 0.5 W cm -2 at 850 and 650 °C (calculated from the current overpotential curves) and the high electronic conductivity of (La 0.8 Sr 0.2 ) 0.95 Fe 0.8 Ni 0.2 O 3-d (LSFN) make this material a promising candidate for SOFC cathodes. Nevertheless, an assessment of LSFN as an SOFC cathode on technically relevant cell sizes and oxygen utilisation-to the best of our best knowledge-has not been reported so far.