Nanosized Ce_(0.8)Sm_(0.2)O_(1.9) infiltrated GdBaCo_2O_(5-δ) cathodes for intermediate-temperature solid oxide fuel cells

摘要

In this paper, Ce_(0.8)Sm_(0.2)O_(1.9) (SDC) nanoparticles modified GdBaCo_2O_(5-δ) (GBCO) cathodes were fabricated by an infiltration technique and evaluated for intermediate-temperature solid oxide fuel cells (IT-SOFCs). Good chemical compatibility between GBCO and infiltrated SDC was confirmed by X-ray diffraction (XRD) characterization. SDC nanoparticles (~40 nm) formed continuous ionic-conducting phase on porous GBCO backbone, which contributed to significantly improved electro-catalytic property. At 600 °C, the composite cathode with 3.3 mg cm~(-2) SDC loading exhibited encouragingly low R_p value of 0.1 Ω cm~2, which was much lower than 0.43 Ω cm~2 of pure-GBCO cathode. As revealed by PO_2 dependence of impedance spectra, the oxygen reduction reaction was mainly limited by charge-transfer processes. Furthermore, a stable operation of 80 h was obtained at 600 °C. Our study implies that infiltrated GBCO cathode is very attractive for application in IT-SOFC cathode.