Hybrid Supercapacitors Based on Activated Carbons and Conducting Polymers (original) (raw)
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Conducting polymers as electrode materials in supercapacitors
Solid State Ionics, 2002
This paper summarizes the performance data of conventional and especially designed thiophene-based conducting polymers for use as positive and negative electrodes in n/p type supercapacitors. Performance data of polymer composite electrodes are also compared with those of high surface area carbon-based composite electrodes. On the basis of capacity, capacitance and electrode charging resistance data, we selected the best electrode materials, and assembled and tested galvanostatic chargedischarge cycles n/p type pMeT-based supercapacitors and hybrid supercapacitors with pMeT as positive electrode active material and activated carbon as negative. The results of this investigation demonstrate that a conventional polymer such as pMeT can be successfully used in the supercapacitor technology when a hybrid configuration is realized; its use is, indeed, a great advantage because the hybrid supercapacitor outperforms the double-layer carbon supercapacitors presently on the market in terms of specific energy and power. D
Asymmetric supercapacitor devices based on dendritic conducting polymer and activated carbon
Electrochimica Acta, 2017
Dendritic conducting polymers(CPs) are a novel class of porous pseudocapacitive electrode materials assembled with the combination of highly reversible redox active triphenylamine(TPA) and thiophene, 3-methylthiophene, selenophene and thieno[3,2-b]thiophen moieties. Due to the unique combination of three dimensional conducting network, fast redox reversible reactions, porous morphology, high thermal and electrochemical stability have fetched these pseudocapacitive polymers to exhibit high specific capacitance and emerged as an ideal candidate for energy storage devices. The electrochemical performance of as-prepared polymers showed specific capacitance of 278, 257, 246 and 315 Fg-1 for poly tris[4-(2-thienyl)phenyl]amine (P1), poly tris(4-(3-methylthiophene-2yl)phenyl)amine (P2), poly tris(4-(selenophen-2-yl)phenyl)amine (P3) and poly tris(4-thieno[3,2-b]thiophen-2-yl) phenyl)amine (P4) respectively with low internal resistance. An insertion of selenophene and thieno(3,2-b)thiophene linkers in TPA block showed enhanced electrochemical performance than the thiophene-TPA pair. Furthermore, asymmetric supercapacitors were assembled with the polymer as cathode and activated carbon as an anode and the detailed electrochemical characterizations has been investigated. This research may shed light on designing new redox active psuedocapacitors and other electrochemical devices.
Journal of Solid State Electrochemistry, 2014
r o l y t e o f s o d i u m bis(trifluoromethanesulfonyl)imide (NaTFSI)-polyethylene oxide (PEO) in an organic solvent mixture has been prepared and examined for supercapacitor applications by using activated carbon electrodes. The solvent was a mixture of propylene carbonate, dimethyl carbonate, and ethylene carbonate at equal molar ratio, and also, a propylene carbonate-based gel was used for a comparison. The polymer-salt interaction was viewed by infrared spectral study. The cells have been characterized in a two-electrode type using linear sweep voltammetry, cyclic voltammetry, galvanostatic cycling, and impedance techniques at 22°C. The voltammograms evidence symmetry and reversibility of the cells. The ternary gel has shown better electrochemical performances. Moreover, the cell operative potential window was found to be stable at 2.5 V with high specific capacitance and also a good efficiency at low charge rate. The typical obtained specific capacitance, real power, and energy density values are 24 F g −1 , 0.52 kW kg −1 , and 18.7 Wh kg −1 , respectively, which may be viewable for a compact capacitor.
Electrochimica Acta, 2012
In the present work, we report high temperature performance of solid electrolyte supercapacitor based on activated carbon (AC) and phosphoric acid doped poly [2,5 benzimidazole] (ABPBI). Supercapacitors with varying concentrations of solid electrolyte in the electrode were fabricated and unit cells were analyzed over a wide temperature range of 27-120 • C. Supercapacitor with AC/ABPBI wt ratio 1.0:0.25 exhibited a specific capacitance of 197 F g −1 at room temperature. To the best of our knowledge, the value reported here is one of the highest for electric double layer supercapacitor with a solid electrolyte. The specific capacitance of supercapacitors having various compositions increased with temperature. The specific capacitance for AC/ABPBI wt ratio 1.0:0.25, capacitance increased to 248 F g −1 at 120 • C. The performance of supercapacitors was also analyzed by electrochemical impedance spectroscopy. The Nyquist plots at room temperature and 100 • C were studied by fitting them using Randles equivalent circuit. Supercapacitor with AC/ABPBI wt ratio 1.0:0.25 showed phase angle of 86.8 • at low frequency which indicated excellent capacitive behavior at room temperature. The supercapacitor was found to have good stability during galvanostatic charge-discharge cycling even after repeated heating and cooling.
Carbon, 2014
The performance of supercapacitor cells with activated carbon (AC) electrodes was improved by adding a small amount of multiwall carbon nanotubes (MWCNTs). The electrode structure investigated comprised AC, four different types of MWCNTs and two polymer binders, polyvinylidene fluoride or polyvinyl alcohol. All fabricated devices were of the electrochemical double layer capacitor type. The organic electrolyte used was tetraethyl ammonium tetrafluoroborate (TEABF 4) in two different solvents: propylene carbonate or acetonitrile (AN). The electrodes were characterised with scanning electron microscopy and tested for their specific surface area and pore size distribution. The electrode fabrication process was fine-tuned by investigating the effect of the coating thickness on the supercapacitor cell performance. It was established that an AC/MWCNT-based supercapacitor with 30 lm thick roll-coated, composite electrodes of just 0.15%w/w MWCNT content provided superior tested power and energy densities of 38 kW/kg and 28 W h/kg, respectively, compared to 18 kW/kg and 17 W h/kg for AC only-based cells in a 1.5 TEABF 4 /AN electrolyte. The increased energy density was attributed to a fine lace of MWCNTs covering the AC microparticles with visible 20-30 nm lace pores and to the high specific area of micropores.
Materials Today Energy, 2018
High energy density but not at the expense of power density, large areal and gravimetric capacitances, durability, lightweight, ease of fabrication, low self-discharge rates, low cost, eco-friendly, non-hazardous components to enable scale-up and safe disposal are the desirable prerequisites that supercapacitors are expected to satisfy so that they can bridge the gap between batteries and sole carbon based supercapacitors. These requirements are met in a hybrid based on poly(3,4-ethylenedioxythiophene) (PEDOT) fibers, a robust, inexpensive, easily processable conducting polymer, with an another remarkably cheap, CO 2 activated carbon (CO 2 @C) derived from rice husk, a waste by-product of rice manufacturing, which is abundantly available (for two-thirds of the world's population consumes rice). The PEDOT-CO 2 @C hybrid based symmetric flexible supercapacitor delivers gravimetric and areal capacitances of 458 F g À1 (at 1 A g À1) and 850 mF cm À2 over a wide voltage window of 2.1 V, an equilibrated low leakage current of 0.14 mA, an exceptionally high energy density of 280 Wh kg À1 at a power density of~1 kW kg À1 , a low diffusion resistance of 3 U and a capacitance retention of~98% over 5000 cycles. These performance metrics are significantly superior to that exhibited by symmetric cells of sole CO 2 @C or PEDOT electrodes. This study shows that the PEDOT-CO 2 @C hybrid overcomes the major limitations that a majority of the lab-level supercapacitors suffer from: low energy density and a processing methodology that is cost effective and scalable simultaneously. Three charged PEDOT-CO 2 @C hybrid based symmetric supercapacitors are connected in series. Using this assembly, red and yellow LEDs are illuminated, and a commercial glucometer is powered by replacing the 3 V battery with the hybrid supercapacitors. The latter demonstration opens up an exciting possibility of powering a range of micro-diagnostic devices with this easy to use, handle and dispose hybrid supercapacitors instead of toxic, difficult to dispose-batteries.
2018 7th International Conference on Computer and Communication Engineering (ICCCE), 2018
A simple RC equivalent circuit model often used to represents a supercapacitor. The model is far from accurately model the behavior of the device. A 2cm by 2 cm supercapacitor prototype based on Activated carbon as the active electrode material and NaOH as the electrolyte was fabricated. This prototype was characterized using Cyclic Voltammetry and Galvanostatic Charge Discharge to get the supercapacitor working potential window, capacitance and internal resistance. The device works up to 0.7V with capacitance of up to 1.6F and internal resistance as low as 190 Ohm was found for the prototype. Several equivalent circuit model of a supercapacitor was simulated to produce similar response of the prototype. Multiple Branch Parallel RC circuit response profile fit the experimental profile the best.
An activated carbon monolith as an electrode material for supercapacitors
2009
Activated carbon binderless monoliths with high consistency and large porosity, synthesised from a mesophase pitch, are studied as electrodes for supercapacitors. The electrochemical cells prepared provided high capacitance values in sulphuric acid media (334 F g-1) and very low electrical resistivity, which results in a very efficient energy storage device (12 Wh Kg-1 maximum energy density and 12,000 W Kg-1 maximum power density). Long-term cycling experiments showed excellent stability with a reduction of the initial capacitance values of 19 % after performing 23,000 galvanostatic cycles at ∼300 mA g-1 .
Journal of Power Sources, 2001
The use of electronically conducting polymers (ECPs) as pseudocapacitive electrode materials in high-power supercapacitors is a challenge to overcome the performance of carbon-based double-layer supercapacitors for applications requiring high power levels. ECPs provide different supercapacitor con®gurations but devices with the polymer n-doped form as the negative electrode and the p-doped form as the positive one are the most promising in term of energy and power. This type of supercapacitor has indeed a high operating voltage, it is able to deliver all the doping charge and it has in the charged state both electrodes in the conducting (p-and n-doped) states. Data for poly(3-methylthiophene) positive and negative electrodes, envisioned for a n/p-type supercapacitor, as well as data for cyclability of supercapacitors with composite electrodes based on such conventional polymer are here reported and discussed. The capacitance and cycling stability of poly(3-methylthiophene) are suf®ciently high to take this polymer into consideration for supercapacitor technology. #
C
A novel flexible supercapacitor device was developed from a polyethylene terephthalate substrate, reused from beverage bottles, and a conductive ink based on carbon black (CB) and cellulose acetate (CA). The weight composition of the conductive ink was evaluated to determine the best mass percentage ratio between CB and CA in terms of capacitive behavior. The evaluation was performed by using different electrochemical techniques: cyclic voltammetry, obtaining the highest capacitance value for the device with the 66.7/33.3 wt% CB/CA in a basic H2SO4 solution, reaching 135.64 F g−1. The device was applied in potentiostatic charge/discharge measurements, achieving values of 2.45 Wh kg−1 for specific energy and around 1000 W kg−1 for specific power. Therefore, corroborated with electrochemical impedance spectroscopy assays, the relatively low-price proposed device presented a suitable performance for application as supercapacitors, being manufactured from reused materials, contributing ...