Surface Fluorination of PAN-Based Carbon Fibers Electrodes for High Energy Density Supercapacitor

This study aims to enhance the electrochemical performance of supercapacitors by maximizing the specific surface area and surface treatment of carbon-material electrodes through fluorination doping. Polyacrylonitrile (PAN)-based carbon fibers (PCFs) were produced via electrospinning and subsequently activated with potassium hydroxide (KOH) at 800 °C to obtain activated PAN-based carbon fibers (APCFs). Direct fluorination was then used to synthesize fluorinated PAN-based carbon fibers (FPCFs). The specific surface area of the electrode materials was maximized by adjusting the concentration of the electrospinning solution. The effect of fluorination on changes in surface elemental content was precisely managed to mitigate the decrease in porosity. The pore size distribution, vital for determining the specific capacitance of supercapacitors, was thoroughly assessed. After the activation and fluorination processes, the specific surface area of the FPCFs increased significantly to 1753.2 m2 g–1. This value is notably higher than that of commercial activated carbons, which typically range from 1200 to 1500 m2 g–1. The supercapacitor properties of the resulting materials were evaluated, revealing a specific capacitance of 176.2 F g–1 for FPCF with an electrospun PAN concentration of 7 wt %.