Y doped La2Ce2O7 proton conducting SOFC electrolyte membrane: Thin film deposition via EPD, electrochemical performance and DRT analysis

Abstract

Herein, a new series La2-xYxCe2O7 (x = 0, 0.05, 0.10, 0.15 and 0.20) as electrolyte materials are investigated for intermediate temperature SOFCs application. The adopted synthesis route for nano sized La2-xYxCe2O7 powder is glycine nitrate combustion. The crystal structure and phases present in the Y doped La2Ce2O7 is studied extensively using X-ray diffraction and Raman spectroscopy. The material exhibits dual phase fluorite (F) type and C type phases. The structural relationship along with oxygen vacancies are critically analyzed. The ionic conductivity of the Y doped La2Ce2O7 series are studied and La1.85Y0.15Ce2O7 exhibits the highest ionic con-ductivity of 3.29 x 10-3 Scm- 1 in moist atmosphere at 700 degrees C. The stability and suspension chemistry of La1.85Y0.15Ce2O7 is investigated in different suspension media and then electrophoretic deposition (EPD) employed to fabricate the thin (-13 mu m) and dense electrolyte on the fuel electrode. The cell demonstrated a maximum power density (MPD) of roughly 500, 353.6, and 197 mW cm-2 at 700 degrees C, 650 degrees C, and 600 degrees C, respectively. The cell is found to be stable under constant operation of short-term stability test at 700 degrees C. The distribution of relaxation time (DRT) from the impedance spectra suggests that the gas diffusion process in the electrodes contributes greatly to the overall polarization of the cell.