Synthesis and characterization of electrospun polyvinylidene fluoride (PVdF)-based polymeric separators for supercapacitor applications
This study outlines the synthesis and characterization of electrospun polymer-based nanofibers with carbon black nanoinclusions for separators in supercapacitor applications. Supercapacitors, also known as ultracapacitors, are a new generation of storage devices used to store an electrical charge with a high power density and having a long life cycle compared to other storage devices. Polyvinylidene fluoride (PVdF)/polyvinylpyrrolidone (PVP) incorporated with carbon black nanopowders were synthesized via the electrospinning method for supercapacitor separators. Morphological characterizations of the PVdF/PVP nanofiber separators by scanning electron microscopy (SEM) show that the nanoscale fiber structures have a diameter range of 100 to 200 nm. Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and x-ray diffractometry (XRD) were also employed to study the microstructures, crystalline phases, and chemical bondings. Total capacitance values of PVdF/PVP nanofibers were enhanced due to the pseudocapacitance effect in the presence of oxygen and nitrogen functional groups. Test results revealed that the ionic conductivity, dielectric constant, and wetting properties of electrospun nanofibers were improved. This investigation demonstrated that the porous nanocomposite fibers have shown increased physical and electrical properties. The effect of heat treatment and ultraviolet (UV) irradiation exposure on the PVdF/PVP nanofibers demonstrated better dielectric constant values and surface wettability. Overall, this study showed that enhanced physical, electrical, and thermal properties are useful for supercapacitor separator applications. Supercapacitors will become one of the most favorable storage devices in the future, and separators are one of their major components.
Thesis (Ph.D.)-- Wichita State University, College of Engineering, Dept. of Mechanical Engineering