Preparation of Pr, Co co-doped BaFeO3–δ-based nanofiber cathode materials by electrospinning

Abstract

The solid oxide fuel cell (SOFC) is considered promising technology that directly converts the chemical energy stored in the fuel into electrical energy. However, the undesired oxygen reduction reaction (ORR) activity and stability of the cathode have hindered its commercialization. In this work, a series of Pr-doped PrxBa1-xFe0.8Co0.2O3-δ (x = 0∼0.3) nanofibers and powder cathode materials with excellent performance are synthesized by electrospinning and sol-gel methods, respectively. The influence of different Pr doping amounts on the nanofiber morphology, phase structure, thermal stability and electrochemical properties of BaFe0.8Co0.2O3-δ (BFCO) nanofibers cathode materials were investigated. Compared the microstructures and electrochemical performance of Pr0.1Ba0.9Fe0.8Co0.2O3-δ nanofiber and powders prepared by different methods. The partial substitution of Pr for Ba (doping of a few of Pr) can effectively eliminate the BFCO hexagonal phase and induce the transformation to the cubic phase. The content of oxygen vacancies was significantly increased as well as the cathode ORR activity was well enhanced. In addition, we demonstrated by DRT that oxygen adsorption is the rate-limiting step at the cathode. Among them, Pr0.1Ba0.9Fe0.8Co0.2O3-δ nanofiber has the best electrochemical performance and the highest oxygen surface exchange kinetics performance. The area-specific resistance (ASR) of Pr0.1Ba0.9Fe0.8Co0.2O3-δ nanofiber is 0.1416 Ω cm2 at 700 °C. When the peak power density (PPD) of the YSZ-NiO/YSZ/GDC/PBCF1–F single cell shows 0.787 W cm−2, an anode-supported fuel cell with Pr0.1Ba0.9Fe0.8Co0.2O3-δ nanofiber demonstrates excellent stability after 100 h of long-term stability test. Electrospinning technology is an effective method to prepare high-performance cathodes, and Pr0.1Ba0.9Fe0.8Co0.2O3-δ nanofiber cathodes are expected to be high-performance cathode materials for IT-SOFCs.