Preparation and characterization of YDC-BCFN as nanocoating on the cathode of IT-SOFC

Abstract

Abstract Using metal nitrates, Nb2O5, citric acid and Ethylenediamine Tetraacetic Acid (EDTA) as raw materials, Ba1.0Co0.7Fe0.2Nb0.1O3 − δ (BCFN) nanopowders were successfully prepared by an EDTA-citric acid complex method. The synthesis process, thermal decomposition behavior, phase variation and micro-morphology of the precursor and obtained nanopowders were characterized by TG/DSC, FTIR, XRD and TEM combined with selected area electron diffraction (SAED) techniques. The cubic perovskite-type structure BCFN nanopowders could be obtained at 950 °C with an average crystallite size of ~ 60 nm. The redox performance was studied using O2 temperature programmed desorption (O2-TPD) and H2 temperature programmed reduction (H2 –TPR). BCFN nanopowders exhibited better oxygen reduction ability than micron powders at lower temperature. Both BCFN nanopowders and micron powders were mixed with Ce0.8Y0.2O2 − δ (YDC) nanopowders with mass ratio of 1:1, respectively. The mixed powders were coated on a BCFN-Ce0.8Gd0.2O2 − δ (GDC) composite cathode in order to lower its polarization resistance. The results showed that the BCFN-GDC/GDC/BCFN-GDC symmetric cell with BCFN-YDC nanocoating exhibited lower polarization resistance compared to samples with BCFN-YDC micron size coating or without coating.