Durable high-performance Sm0.5Sr0.5CoO3–Sm0.2Ce0.8O1.9 core-shell type composite cathodes for low temperature solid oxide fuel cells

✍ Scribed by Daehee Lee; Inyong Jung; Seong Oh Lee; Sang Hoon Hyun; Jae Hyuk Jang; Jooho Moon

• Publisher: Elsevier Science
• Year: 2011
• Tongue: English
• Weight: 933 KB
• Volume: 36
• Category: Article
• ISSN: 0360-3199
• DOI: 10.1016/j.ijhydene.2011.02.093

✦ Synopsis

Sm 0.5 Sr 0.5 CoO 3 (SSC)eSm 0.2 Ce 0.8 O 1.9 (SDC) core-shell composite cathodes are synthesized via a polymerizable complex method, and the durability of a cell incorporating the cathodes is examined. Nanocrystalline SSC powders have been coated onto the surfaces of SDC cores to enable the formation of a rigid backbone structure, over which the catalyst phase is effectively dispersed. A symmetrical SSCeSDC jSDCj SSCeSDC half-cell exhibits a polarization resistance of 0.098 U cm 2 at 650 C. The durability and microstructure of the cathode are investigated by electrochemical impedance spectroscopy and thermo-cycle tests at temperatures in the range of 100 Ce650 C. After 30 cycles, the polarization resistance is found to increase by 9.04 Â 10 À2 U cm 2 , a 3.56% rise with respect to the initial resistance. Coarsening of the SSC catalyst phase has been prevented with the use of core-shell type powders, as confirmed by a nearly constant low frequency polarization resistance and a microstructural analysis. The performance of a unit cell comprised of the core-shell type cathode exhibits 1.07 W cm À2 at 600 C and 0.62 W cm À2 at 550 C.