Single crystalline La0.5Sr0.5MnO3 microcubes as cathode of solid oxidefuel cell

Abstract

The efficiency of solid oxide fuel cells (SOFCs) is heavily dependent on the electrocatalytic activity of the cathode toward the oxygen reduction reaction (ORR). In order to achieve better cathode performance, single crystalline La_0.5Sr_0.5MnO₃ (LSM) microcubes with the {200} facets have been synthesized by the hydrothermal method. It is found that the LSM microcubes exhibit lower polarization resistance than the conventional polycrystalline La_0.8Sr_0.2MnO₃ powder in air from 700 °C to 900 °C. The ORR activation energy of the LSM microcubes is lower than that of the conventional powder. The ORR kinetics for the microcubes is limited by the charge transfer step while that for the conventional powder is dominated by the oxygen adsorption and dissociation on the cathode surface.