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 conductivity of 3.29 × 10−3 Scm−1 in moist atmosphere at 700 °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 μm) 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 °C, 650 °C, and 600 °C, respectively. The cell is found to be stable under constant operation of short-term stability test at 700 °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.