Tailoring La2-XAXNi1-YBYO4+δ cathode performance by simultaneous A and B doping for IT-SOFC

• DOI: 10.1016/j.ijhydene.2020.03.150
• Publication Date: 2020-05-11T00:02:17Z
• Authors: L. Navarrete; M. Fabuel; C.-Y. Yoo; J.M. Serra
• Keywords: 01 natural sciences; 7. Clean energy; 0104 chemical sciences

The present work focuses on the study of different Ruddlesden-Popper based cathode materials for Solid Oxide Fuel Cells at Intermediate Temperature (IT-SOFC). The partial substitution of La and Ni by Pr and Co, respectively, were studied in the LaPrNiCoO system, with the purpose of enhancing their mixed ionic-electronic conductivity and the electrocatalytic activity for the O-reduction while the crystal structure was preserved. All synthesized compounds were characterized by electrochemical impedance spectroscopy (EIS), DC conductivity measurements, X-Ray diffraction (XRD), iodometric titration and scanning electron microscopy (SEM). XRD analyses by Rietveld refinement revealed the influence of the ionic radius on the crystalline phase for the different dopants, i.e., variation of the cell parameters and M−O bond lengths. The substitution in both La and Ni sites improves LaNiO electrochemical properties as IT-SOFC cathode, since higher conductivity and lower polarization resistance were obtained. Finally, LaPrNiCoO cathode exhibited the lowest electrode polarization resistance and activation energy values in the temperature range of 450–900 °C. LaPrNiCoO was applied on an anode supported cell and a maximum power density of ~400 mW cm was obtained at 700 °C using pure hydrogen and air. This work was financially supported by Spanish Government (Grants SEV-2016-0683 and RTI2018-102161) and Generalitat Valenciana (PROMETEO/2018/006). Vicente B. Vert, Ji Haeng Yu and Dae Sik Yun are kindly acknowledged for their support during this work preparation and Forschungszentrum Jülich for providing the anode supported cell.