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Characterizations of LBC-GDC Composite Cathodes for Low Temperature SOFCs

2011; Institute of Physics; Volume: 158; Issue: 9 Linguagem: Inglês

10.1149/1.3606475

1945-7111

Ruhul Amin, Ben Kenney, Kunal Karan,

Magnetic and transport properties of perovskites and related materials

This study reports on the physico-electro-chemical characterization of porous composite electrodes made of lanthanum-barium-cobalt oxide (LBC) electrocatalyst and gadolinium-doped-cerium oxide (GDC) oxygen-ion conductor. Four different compositions of LBC-GDC composite electrodes were fabricated and heat-treated at 1150°C. The phase purity of the heat-treated LBC-GDC composite was checked by X-ray diffraction measurements. Thermal expansion coefficient (TEC) was measured from room temperature to 900°C. Porous LBC-GDC composite electrodes were studied in a symmetrical cell configuration by impedance spectroscopy where gadolinium doped ceria (GDC) was used as a solid electrolyte. Impedance spectra obtained at zero dc bias conditions consisted of two semi-circular arcs, which indicate that the overall oxygen reduction comprises at least two distinct processes. The area specific resistance (ASR) for electrode polarization was measured in the 600–800°C temperature ranges. The lowest ASR value of 0.06 Ω cm−2 at 600°C was exhibited by LBC/GDC composite of composition 60/40. The ASR values at lower temperatures offer the promise of utilizing composite as a cathode for low-temperature SOFCs.