A promising cathode for intermediate temperature protonic ceramic fuel cells: BaCo0.4Fe0.4Zr0.2O3−δ

Abstract

In this study, BaCo_0.4Fe_0.4Zr_0.2O_3−δ (BCFZ), which has been previously investigated as a stable oxygen permeable membrane material, is confirmed to be a promising cathode for intermediate temperature protonic ceramic fuel cells (IT-PCFCs). BCFZ shows lower electrode polarization resistances, longer performance stability, and better compatibility with the state of the art protonic ceramic electrolyte BaCe_0.7Zr_0.1Y_0.1Yb_0.1O_3−δ (BCZYYb) than the prevailing cathode La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ (LSCF). The oxygen reduction reaction (ORR) mechanism and the reaction kinetics are also investigated in detail. A single cell constructed from the BCFZ cathode with a BCZYYb electrolyte and BCZYYb-Ni anode demonstrates a power density of 225 mW cm⁻² at 600 °C, which is ∼20 times greater than a single cell constructed from an LSCF cathode with the same electrolyte and anode under the same operating conditions.