Porous an hollow nanofibers for solid oxide fuel cell electrodes

Among the diverse approaches for improving the electrode performance of solid oxide fuel cells operating at intermediate temperatures, the use of nanofiber-based electrodes has provided large improvement owing to their large specific surface area, continuous conduction pathway, and highly porous structure. However, the low thermal stability at increased temperature often limits the process compatibility and sustainability during operation. In this study, we fabricated nanofiber-based electrodes with a high porosity and hollow shape using one-step electrospinning with a hydrogel polymer, which exhibited largely improved performance and excellent thermal stability. A porous-nanofiber-based cell exhibits a polarization resistance of 0.021 Ωcm² and maximum power density of 1.71 W/cm² at 650 °C, which is an improvement of 34.3% and 14.7% compared to that of a solid-nanofiber-based cell, respectively. Comprehensive analyses of the microstructures and chemistry indicate that the performance increase is mainly attributable to the enhanced surface oxygen exchange reactions owing to the extended reaction sites with lower energy barriers by the high porosity and enriched oxygen vacancies in the nanofibers.