Electrophoretic Deposition of Gadolinium‐doped Ceria as a Barrier Layer on Yttrium‐stabilized Zirconia Electrolyte for Solid Oxide Fuel Cells

Abstract

AbstractReplacing the electronically conductive (LaSr)MnO3±δ (LSM) cathode in the LSM/yttrium‐stabilized zirconia (YSZ) system with the mixed ion‐electron conductive (MIEC) (LaSr)(CoFe)O3–δ will promote cathode performance in solid oxide fuel cells (SOFCs) significantly. However, a barrier layer between LSCF and YSZ is necessary for preventing chemical reaction between these two components. In this study, a gadolinium‐doped ceria (GDC) barrier layer was deposited on the YSZ electrolyte by scalable and cost‐effective electrophoretic deposition (EPD). Polypyrrole (PPy) was coated on the YSZ surface as the conductive agent. A highly compact GDC green layer was obtained by the EPD process in an ethanol‐based suspension. GDC barrier layers ranging in thickness from 5 µm to 8 µm were successfully densified at temperatures as low as 1,300 °C. The performance of these cells was evaluated using a symmetrical cell configuration through electrochemical impedance spectroscopy (EIS). Ohmic resistance of the GDC barrier layer made by EPD versus the conventional spin‐coating method was reduced by 0.09 Ω cm2 at 750 °C, which generally accounts for 30% of the total ohmic resistance for the electrode‐supported fuel cells (0.30 Ω cm2). This result suggests that EPD is a highly desirable method for efficiently manufacturing an electrolyte barrier layer with improved performance.