Electrochemical capacitors or supercapacitors are electrochemical systems that can store and release energy with pulse-power. Carbon fiber cloths have been recognized as the best supports as supercapacitor materials by providing high specific surface area, electrical conductivity, and flexibility compared to a wide range of used substrates such as nickel foam, 1D iron nanowires, etc. So far, various metal oxides, chalcogenides, phosphides, 2D metal carbides, carbon nanotubes, graphene, and conductive polymers have been composited to improve carbon fiber cloth's charge storage activity. In the present study, electrodes for use in flexible wearable supercapacitors were fabricated using sulfuric acid-doped polyaniline (acting as a pseudocapacitor) deposited onto activated carbon fibers (ACFC) (which can be solely used as supercapacitor electrode material) and coated on activated carbon fibers (PANI/ACFC). Initially, carbon fibers were oxidized via electrochemical anodization (potentiostatic) in 1 M H2SO4 solution at room temperature to provide a high specific surface area and enhance capacitive properties. Subsequently, polyaniline was coated onto the oxidized carbon fibers from a bath containing 0.2 M aniline monomer and 1 M H2SO4 as the dopant material using the potentiostatic electrochemical method on the previously oxidized carbon fibers. To modify and improve the pseudocapacitive properties and cyclic stability of PANI/ACFC electrodes, the effect of various coating parameters such as potential and time in potentiostatic method on the morphology, microstructure, and electrochemical behavior of PANI/ACFC electrodes were eva‎luated and studied. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and Scanning Electron Microscopy (SEM) were used for microstructural and morphological investigations. Electrochemical eva‎luations were conducted using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) at room temperature in 1 M H2SO4 electrolyte. It was found that the electrode produced at a potential of 0.95 V for an electro-polymerization time of 150 seconds showed the highest capacitance value of 1475 mF.cm-2 at a scan rate of 5 mV.s-1 and the highest rate capability. Moreover, this electrode could retain 48% of its initial capacitance after 500 charge-discharge cycles at a scan rate of 100 mV.s-1.

كيوان رئيسي , مهران نحوي

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