Electrochemical properties of graded and homogeneous Ce0.9Gd0.1O2−δ–La0.6Sr0.4Co0.2Fe0.8O3−δ composite electrodes for intermediate-temperature solid oxide fuel cells

Abstract

Graded and homogeneous CGO–LSCF composite electrodes deposited by Electrostatic Spray Deposition on an YSZ substrate have been studied with and without screen-printed LSCF current collector. Impedance spectroscopy measurements have been performed in air at open circuit potential between 450 °C and 700 °C; and during isothermal treatments at 600 °C for 200 h; and at 800 °C for 12 h to estimate the relevance of such oxygen electrodes for intermediate temperature solid oxide fuel cells (IT-SOFCs). A thin and dense CGO layer is firstly deposited to avoid any chemical reaction between LSCF and YSZ. No significant increase of the polarization resistance has been evidenced during isothermal test at 600 °C for 200 h, proving good stability of the electrode. Using a LSCF current collector layer (CCL), the polarization resistance decreases by a 1.5 order of magnitude compared to samples with single cathode functional layer (CFL). The electrochemical results do not conclusively indicate which composition presents lower polarization effects.