Sm0.5Sr0.5CoO3 (SSC)-Sm 0.2Ce0.8O1.9 (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 SSC-SDC SDC SSC-SDC half-cell exhibits a polarization resistance of 0.098 Ω cm2 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 °C-650 °C. After 30 cycles, the polarization resistance is found to increase by 9.04 × 10-2 Ω cm2, 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-2 at 600 °C and 0.62 W cm-2 at 550 °C.
Bibliographical noteFunding Information:
This work is the outcome of the fostering project of the Specialized Graduate School of Hydrogen & Fuel Cell supported financially by Ministry of Commerce, Industry and Energy (MOCIE) and Seoul R&BD Program (CS070157). This work was partially supported by the New and Renewable Energy Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government , Ministry of Knowledge and Economy ( 2008-NFC12J0333602009 ).
All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment
- Fuel Technology
- Condensed Matter Physics
- Energy Engineering and Power Technology