Application of Ba0.5Sr0.5FeO3−δ-NdMnO3−δ Composite Cathode in Proton-Conducting Solid Oxide Fuel Cells

Abstract

Ba0.5Sr0.5FeO3−δ (BSF) nanofibers are prepared via electrospinning and sintering at a temperature of 800 °C for 2 h to produce a pure cubic perovskite phase, with the aim of finding a high-performance cathode material suitable for proton-conducting solid oxide fuel cells (PCFCs) operating at medium temperatures. The results of SEM analysis showed that the BSF nanofibers are alternately stacked, presenting fluffy and uniform high porosity, which is favorable to the cathode polarization reaction of PCFCs. To balance the excessive coefficient of thermal expansion of the BSF cathode, it is combined with a negative thermal expansion (NTE) material NdMnO3−δ (NM). At 700 °C, the peak power density (PPD) of the BSF–NM cathode cell is 1170 mW cm−2, and the open-circuit voltage (OCV) of the single cell is 1.04 V. The corresponding polarization impedance (Rp) of the BSF–NM is 0.037 Ω cm2. This result is significantly better than the previously reported powder cathode BSF, indicating that the performance of PCFC can be further optimized by transforming the BSF cathode into a nanofiber state and compounding it with the NTE material NM.