| 초록 |
For intermediate-temperature SOFC (IT-SOFC), scandia-stabilized zirconia (SSC) was selected as the electrolyte material since it shows the highest ionic conductivity among the zirconia-based oxide material. Due to high polarization resistance of the cathode in low-temperatures (600~700oC), an ideal cathode material should have mixed ionic and electronic conductivities as well as proper catalytic properties. We have synthesized well-engineered nanocomposite particles for the achievement of low polarization resistance and highly durable solid oxide fuel cell cathodes. The use of a dual-composite approach in which both LSCF and SDC phases are placed on a SDC grain allows for the development of an ideal cathode microstructure with improved phase contiguity and interfacial coherence. SEM, XRD, dilatometer were employed to analyze microstructure of the cathode layers. The impedance spectra were obtained over a frequency range from 100 kHz to 0.1 Hz with an applied ac voltage amplitude of 20mV at temperatures from 550 to 700 oC in 50 oC intervals. Full cell performance was also investigated using the Solartron 1286 interfaced with a computer in humidified hydrogen as a fuel and air as an oxidant at ambient pressure. |
