Insight into the Electrospinning Process for SOFC Cathode Nanofibers

Abstract

La1–xSrxCo1–yFeyO3-δ (LSCF) and La1–xSrxMnO3-δ (LSM) are typical cathode materials for solid oxide fuel cells (SOFC). The nanofibers of these materials prepared by electrospinning technology show excellent electrochemical performance. In this work, the electrospinning process for these two materials was investigated in detail. The viscosity and the conductivity of the electrospinning solution were tested. The focus was on evaluating the effect of nitrate concentration on the minimum voltage for a nondripping drop (Vmin). A model of the electrospinning process was proposed to understand the electrospinning process intuitively. The results show that adding LSCF and LSM nitrate to the electrospinning solution affects the solution viscosity by increasing it 3-fold compared to the nitrate-free solution, followed by increases in conductivity and Vmin. This results in a difference in the size and morphology of the nanofibers, probably depending on the types of element, the valence state, and the content of metal ions per unit volume. It is found that 470.6–2267 mP·s and 7.69–17.07 mS/cm are the appropriate values for the viscosity and conductivity, respectively, to obtain relative uniform nanofibers by applying a Vmin in the range of 17–26 kV. The results in this work are expected to serve as a reference for the industrialization of LSM/LSCF nanofiber electrodes and the preparation of other SOFC nanofiber cathodes by electrospinning.