PVdF‐based electrospun fibers with various morphologies and their separator applications for secondary batteries

In this study, pristine PVdF nanofibers (PPFs), nanocomposite fibers (NCFs), and bicomponent fibers (BCFs) were prepared by electrospinning. TiO2 and SiO2 nanofillers were used in order to tune the properties and performance of the separators. The morphology, thermal degradation behavior, thermal dimensional stability, mechanical properties, porosity, electrolyte uptake, and electrochemical performance of the samples were investigated. All three morphologies were successfully fabricated under optimized conditions and 15 wt% polymer concentration was found electrospinnable at 0.4 ml h−1 feed rate and under 15 kV applied voltage. Viscosity and conductivity of the spinning solutions were found significant for the fiber morphology. For nanocomposite and bicomponent fibers, TiO2 and SiO2 nanofillers were found to be well dispersed throughout the fiber axis with good adhesion to the matrix. Nanofillers were found to increase the thermal stability, mechanical strength, and electrochemical performance of the separators. Thermal, mechanical properties, porosity, electrolyte uptake, and electrochemical performance of the separators were determined as NCFs > BCFs > PPFs.