Electrospun polyacrylonitrile (PAN) carbon nanofibers (CFNs) as electrode material for supercapacitors: A comprehensive review of synthesis, characterization, and electrochemical performance

Supercapacitors (SCs) are attracting a significant amount of interest as energy storage devices owing to their higher specific power, rapid charging–discharging rate, and prolonged cyclic stability. Carbon-based materials are used frequently in SCs because of their excellent electric conductivity, stable chemical properties, and low cost. Electrospun polyacrylonitrile (PAN)-based carbon nanofibers (CNFs) have attracted much interest as they perform well electrochemically, have a large surface area, and show substantial mechanical characteristics; as well as having a high carbon yield among all polymer PAN. In this paper, an extensive review of the synthesis, characterization, and electrochemical performance of electrospun PAN CNFs is presented. An overview of the electrospinning procedure and properties of PAN CNFs that make them suitable for SC applications is presented. Various characterization methods, including transmission electron microscopy, scanning electron microscopy, x-ray diffraction, Raman spectroscopy, and surface area analysis, have been carried out to evaluate the morphological, structural, and surface properties of PAN CNFs. The review also highlights the recent advances in modification and functionalization to enhance their electrochemical performance, including doping, surface functionalization, and hybridization. Galvanostatic charge–discharge experiments, cyclic voltammetry, and electrochemical impedance spectroscopy have been employed for electrochemical characterization. Finally, a comparative study between various carbon-based and electrospun PAN CNF electrode materials for SCs has been conducted. The review is concluded by discussing the challenges, opportunities, and possible future trends in the development of high-performance electrode material. This comprehensive review provides valuable insightful information on the design and optimization of electrospun PAN CNF electrode materials for SC applications.