Development and performance of MgFeCrO4 – based electrodes for solid oxidefuel cells

Abstract

Composite anodes for solid oxide fuel cells (SOFC) developed on yttria stabilised zirconia (YSZ) porous supports by infiltration of electrode materials has been successfully applied for various anode and cathode compositions, resulting in high performance SOFC devices. The focus of this study is the performance of the chromium-rich spinel (MgFeCrO₄) as an electrode support material when used alone or impregnated. The composite anodes were prepared by aqueous infiltration of nitrate salts to produce (La_0.75Sr_0.25)_0.97Cr_0.5Mn_0.5O_3−δ, Ce_0.9Gd_0.1O_2−δ, CeO₂ or Pd into a MgFeCrO₄ scaffold with 45% porosity and studied by electrochemical impedance spectroscopy in symmetrical cell configuration. The performance was evaluated in humidified 5% H₂/Ar in order to quantify their stability and performance up to 850 °C with respect to the MgFeCrO₄ porous substrate. It was found that all the impregnated phases adhere very well to the spinel and considerably enhance performance and stability to a level required for SOFC applications. MgFeCrO₄/LSCM/CGO and MgFeCrO₄/LSCM/CGO/Pd showed the most substantial improvement in comparison to the scaffold’s performance, with ASR values of 1.74 Ω cm² and 0.91 Ω cm², respectively.