Construction of Heterointerfaces with Enhanced Oxygen Reduction Kinetics for Intermediate-Temperature Solid Oxide Fuel Cells

The intermediate temperature solid oxide fuel cells (IT-SOFCs) whose operating temperature ranges from 873 K to 1073 K have attracted a lot of attention in recent years because of their decreased cost, improved efficiency, and increased turn on/off switch speed. Nevertheless, the reduced performance of the cathode when operating at the intermediate temperature range becomes a challenge, due to the reduced catalytic activity for oxygen reduction reaction (ORR) on traditional cathode materials. Ideal cathodes are required to present efficient charge and oxygen transfer processes. Herein, by constructing heterointerfaces, we designed a novel composite cathode material PrSrFe_0.5Co_0.5O₄-Pr_0.4Sr_0.6Fe_0.5Co_0.5O₃ (PSFC_214-113). According to the X-ray diffraction patterns and high-resolution transmission electron microscopy, the PSFC_214-113 composite material has been synthesized successfully. As a SOFC cathode, PSFC_214-113 maintains a high electronic conductivity and excellent chemical compatibility. Compared to single-phase materials, PSFC_214-113 showed significantly lower electrochemical impedance spectroscopy values and the peak power density of cell reached a power density of 0.73 W cm^-2. The presence of heterointerfaces promoted electronic and oxygen migration which, in turn, enhanced the oxygen reduction kinetics and provided superior electrochemical performance to the material. Our results reveal that the construction of heterointerfaces is an effective strategy to enhance the oxygen reduction kinetics for the high-activity cathode.