Abstract
(Y 0.5In 0.5)BaCo 4-xZn xO 7 (1.0 ≤ x ≤ 2.0) oxides crystallizing in a trigonal P31c structure have been explored as alternative cathode materials for solid oxide fuel cells (SOFC). At a given Zn content, the (Y 0.5In 0.5)BaCo 4-xZn xO 7 compositions exhibit superior phase stability compared to YBaCo 4-xZn xO 7 and InBaCo 4-xZn xO 7 at the operating temperatures of SOFC (600-800 °C). In the (Y 0.5In 0.5)Ba(Co 4-xZn x)O 7 system, the x = 1 sample offers a combination of good electrochemical performance, low thermal expansion coefficient (TEC), and enhanced chemical stability against Ce 0.8Gd 0.2O 1.9 (GDC) electrolyte while demonstrating good phase stability at 600-800 °C for 100 h. Optimum cathode performance could be obtained by employing (Y 0.5In 0.5)BaCo 3ZnO 7 + GDC (50:50 wt.%) composite cathodes attached at 850 °C for 3 h as evidenced by ac-impedance spectroscopy, and the fuel cell performance of this composite cathode was evaluated using anode-supported single cells. With a combination of excellent high-temperature phase stability, low TEC, and good electrochemical performances, the trigonal (Y 0.5In 0.5)BaCo 3ZnO 7 composition is an attractive cathode candidate for intermediate temperature SOFC.
Original language | English |
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Pages (from-to) | 7-14 |
Number of pages | 8 |
Journal | Journal of Power Sources |
Volume | 214 |
DOIs | |
State | Published - Sep 15 2012 |
Funding
Financial support for the work carried at the University of Texas at Austin by the Welch Foundation grant F-1254 and National Science Foundation MIRT grant DMR-1122603 is gratefully acknowledged by Young Nam Kim and Arumugam Manthiram. Research carried out at Oak Ridge National Laboratory (ORNL) was supported by the Laboratory Directed Research and Development (LDRD) Program of ORNL and Jung-Hyun Kim acknowledges the support of ORISE postdoctoral fellowship. Ashfia Huq acknowledges Spallation Neutron Source for financial support which is supported by the Division of Scientific User Facilities, Office of Basic Energy Sciences, U.S. Department of Energy.
Keywords
- Cathodes
- Phase stability
- Solid oxide fuel cells
- Thermal expansion coefficient