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An electrical double-layer capacitor (EDLC) is based on the physical adsorption/desorption of electrolyte ions onto the surface of electrodes. Due to its high surface area and other properties, such as electrochemical stability and high electrical conductivity, carbon materials are the most widely used materials for EDLC electrodes. In this work, we study an activated carbon felt obtained from sheep wool felt (ACF'f) as a supercapacitor electrode. The ACF'f was characterized by elemental analysis, scanning electron microscopy (SEM), textural analysis, and X-ray photoelectron spectroscopy (XPS). The electrochemical behaviour of the ACF'f was tested in a two-electrode Swagelok ®-type, using acidic and basic aqueous electrolytes. At low current densities, the maximum specific capacitance determined from the charge-discharge curves were 163 F•g −1 and 152 F•g −1 , in acidic and basic electrolytes, respectively. The capacitance retention at higher current densities was better in acidic electrolyte while, for both electrolytes, the voltammogram of the sample presents a typical capacitive behaviour, being in accordance with the electrochemical results.

A systematic study using design of experiments was applied in order to map out the thermal stabilization of electrospun polyacrylonitrile mats and to investigate how oxidation and cyclization reactions are affected by rate, temperature, and time in an oxidative environment. Cyclization indexes were estimated by a simple methodology based on differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy data. Values of enthalpy and relative intensities of bands assigned to CN and CN bonds were used on calculation. The statistical planning applied in this study was important to show that not always longest treatment is effective to stabilize polyacrylonitrile, but also samples obtained in less than 3 h presented low values of exothermic peak on DSC, values of cyclization indexes near to 90%, both from DSC and Fourier transform infrared spectroscopy techniques, reduced weight loss in thermogravimetric analysis and O/C ratio higher than 10% by X‐ray photoelectron spectroscopy, that are appreciated characteristics to a precursor of high‐performance carbon materials. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45458.

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The main challenge for the development of a high efficiency supercapacitor is the electrode material. Developing electrode materials with high specific electrical capacitance and low electrical resistance enables an increase in the energy accumulated in the device. In addition, it is expected that the electrode material presents a simple procedure for preparation having low production cost and being environmentally friendly. This work is based on the deposition of silver nanoparticles on activated carbon felt (Ag@ACF) as a supercapacitor electrode. The samples were characterized by field emission gun scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and textural analysis. Supercapacitor behavior was evaluated by galvanostatic charge-discharge curves, cyclic voltammetry and electrochemical impedance spectroscopy using a symmetrical two-electrode Swagelok type cell, and three different aqueous solution electrolytes: 2 M H 2 SO 4 , 6 M KOH and 1 M Na 2 SO 4. Ag@ACF presented a high specific capacitance in KOH, about 170 F g-1 , which makes it an interesting material for supercapacitor electrodes and it showed good specific electrical capacitance, low resistance and high cyclability.

Activated carbon fibers (ACF) are known as excellent adsorbent materials due to their fast adsorption rate and easy handling characteristic. The ACF can be manufactured from the polyacrylonitrile fiber, based on an usual carbon fibers (CF) production process accomplished by an additional activation process. The aim of the present work is to describe the production, chemical/morphological characterization and application potentiality of activated carbon fiber felt (ACFF) produced from textile PAN fiber, using a set of homemade equipment. The 5.0 dtex PAN fiber tow with 200 thousand filaments was oxidized and used as raw material for felt production. The oxidized PAN fiber felt (OPFF) was displaced in a special sample holder, carbonized (900 °C) and then activated in CO 2 atmosphere at 1000 °C in an electric tubular furnace. All steps of the process were performed as fast as possible, and characterization was done by 77 K N 2 isotherms, adsorption isotherms in liquid phase, scanning electronic microscope, X-ray diffraction and surface chemistry by Bhoem methodology. The results confirmed the production of essentially microporous (pore < 3.2 nm, centered on 1.2 nm) and 1,300 m 2 g -1 surface area. The ACFF produced have demonstrated a strong potential application as electrode supercapacitor.

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