We present the electrochemical performance of solid-state EDLCs constructed using composites of perfluorosulfonic acid polymer (Nafion) with micro porous polytetrafluoroethylene (PTFE) membrane and with cellulose acetate (CA), as electrolyte with carbon as electrodes (surface area: 260 m2 g -1). The performance is compared with EDLCs constructed with perfluorosulfonic acid polymer as electrolyte. Scanning electron microscopy is used to study the morphology of the composite electrolyte while micro-Raman and IR measurements determine the integrity of the composite. The performance of the EDLC with perfluorosulfonic acid and PTFE composite electrolyte is good and comparable with the performance of the EDLC with pure perfluorosulfonic acid polymer electrolyte. A specific capacitance of 16 F g-1 is obtained for this EDLC with a maximum working potential of 2.0 V. There is an increase in the equivalent series resistance value from 0.08 Ω for the Nafion EDLC to 4.1 Ω for the Nafion/PTFE composite EDLC. However, the performance of the EDLC with the composite of Nafion/CA is poor due to substantial increase in ESR. The probable reasons are discussed. © 2010 Springer Science+Business Media B.V.

Subramaniam C-K

Department of Physics

School of Advanced Sciences

Vellore Campus

Charge-discharge

ELECTRIC DOUBLE LAYER CAPACITOR

Electrochemical impedance

Micro-Raman

NAFION COMPOSITES

PERFLUOROSULFONIC ACID

Capacitors

Electric discharges

Electrochemical corrosion

Electrolytes

infrared imaging

POLYMER MEMBRANE ELECTRODES

Polymers

Polytetrafluoroethylenes

Scanning electron microscopy

Electrochemical impedance spectroscopy

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Journal of Applied Electrochemistry

Solid state carbon based Electrochemical Double Layer capacitors (EDLC) was assembled and cyclic voltammetry (CV) was studied at high sweep rates. The carbons used were Vulcan XC carbon with typical surface area of 260 m 2/gm, templated mesoporous carbon, (CMK-3), typical surface area of 1260 m2/gm, and a blend of Vulcan XC carbon and mesoporous carbon (90:10% by weight). Solid ionic polymers of perfluorosulphonic acid were used as electrolyte. CV was performed for scan rates as high as 800V/s. Electrochemical impedance spectroscopy, EIS, was used to understand the interface characteristics. It was found that the polymer electrolyte membrane can support high scan rates. The resistance of the EDLC was more emphasized at high scan rates, which maybe due to surface effects rather than bulk characteristics of the carbon. It was found that the change in capacitance was less pronounced at scan rates above 10V/s. ©The Electrochemical Society.

ECS Transactions

Study of Carbon Based Solid State EDLCs at High Sweep Rates

ABSTRACTElectrochemical Double Layer Capacitors, EDLC, using Cobalt sulfide- Graphene (CoSG) composite electrodes, were fabricated and the storage process was studied. CoSG composite was prepared by a simple chemical route. X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA) and Field Emission Scanning Electron microscopy (FESEM) were used to characterized the as prepared composites which indicated formation of Co S phase. Solutions of perfluorosulfonic acid and Polyvinylidene Fluoride (PVDF) were used as electrode binding material. The storage capacitance of the composites were studied in 1M KCl and 6M KOH electrolytes using standard electrochemical techniques like cyclic voltammetry, CV, electrochemical impedance spectroscopy, EIS, and discharge profiles. The capacitance was estimated for various binder concentrations for both the electrolytes. The concentration of perflurosulfonic acid binder of 0.8 wt% and PVDF of 0.04 wt% showed optimized specific capacitances of 657.8 F/gm and 1418.8 F/g, respectively. Some of the problems in storage density in activated carbon, like varying micro or meso pores, poor ion mobility due to varying pore distribution, low electrical conductivity, can be overcome by using Graphene and composites of Graphene. Graphene in various structural nomenclatures have been used by different groups for charge storage. Optimization of the electrode structure in terms of blend percentage, binder content and interface character in the frequency and time domain provides insights to the double layer interface structure.

MRS Proceedings

Cobalt Sulfide-Graphene (CoSG) Composite based Electrochemical Double Layer Capacitors

Solid-state electrochemical double-layer capacitor (SEDLC) forms excellent energy storage device for high-power applications. They are highly reliable, with no electrolyte leaks, and can be packaged to suit various applications. The electrode material can be activated carbon to graphene. These can have a range of particle size, surface area, pore size and pore distribution for charge storage. The emphasis will be to optimize the graphene to carbon blend in the electrodes which would provide appreciable storage density of the SEDLC. We can use perfluorosulfonic acid polymer as the solid electrolyte in the SEDLC assembly. They have high ionic conductivity, good thermal stability, and mechanical strength. They also have excellent long-term chemical stability. Carbon is widely used for many practical applications, especially for the adsorption of ions and molecules, as it is possible to synthesize one-, two- or three-dimensional (1-, 2-, or 3-D) carbons. Some of the problems in activated carbon like varying micro or mesopores, poor ion mobility due to varying pore distribution, low electrical conductivity, can be overcome using graphene and blends of graphene with carbon of the right pore dimension and distribution. Graphene in various structural nomenclatures have been used by various groups for charge storage. Graphene nanoplates (GNP), with narrow mesopore distributions have been effectively used for SEDLCs. SEDLCs assembled with GNP and blends of GNP with Vulcan XC and solid polymer electrolyte like Nafion show exceptional performance. The cyclic voltammetric studies show that they support high scan rates with substantial smaller capacitance drop as we increase scan rates. Optimization of the electrode structure in terms of blend percentage, binder content and interface character in the frequency and time domain provides excellent insight into the double-layer interface. © 2014 Springer-Verlag Berlin Heidelberg.

Applied Physics A

Study of storage capacity in various carbon/graphene-based solid-state supercapacitors

Various carbon-carbon EDLCs were assembled with ionic polymers of perfluorosulphonic acid polymer in the H+, Na+ and K + forms, composites of polytetrafluoro ethylene (PTFE) and perfluorosulphonic acid, PVA-KOH, sulphonated PEEK and PVdF. The surface area of the carbon used in these EDLCs is 260 m2/gm. CV, EIS and discharge profiles were used for characterization. The working voltage of these EDLCs was 2V. The specific capacitance was found to be 20 F/g, 40 F/g and 55 F/g for the perflurosulphonic acid electrolyte in H+, Na+ and K +, respectively. A specific capacitance of 16 F/g was obtained for the EDLC with the composite of PTFE/perluorosulphonic acid and 7.5 F/g and 1.0 F/g for PVA-KOH and sulphonated PEEK electrolyte, respectively. Modules of 5F (2.0V) were developed using carbon electrodes and composites of PTFE/perflurosulphonic as electrolyte. The maximum energy stored in these modules, was of the order of 7.5 Watth/kg. ©The Electrochemical Society.

Solid state EDLCs using various ionic polymers: A study

Journal of New Materials for Electrochemical Systems

10.14447/jnmes.v21i3

A solid-state electrochemical double-layer capacitor (EDLC) was assembled with perfluorosulfonic acid based electrolyte in the HK+, Na +, and K+ forms and with carbon as electrodes (surface area: 260 m2 /g). The performance of these EDLCs was studied using cyclic voltammetry, impedance spectroscopy, and charge-discharge profiles. The assembled cells behaved as EDLCs with a maximum operating voltage of 2.0 V. The specific capacitance was 20 F/g for the electrolyte in HK+ form, 40 F/g for the Na+ form, and 55 F/g for the K+ form. The increase in the specific capacitance may be attributed to the increase in the charge carrying capacity as we move from the proton form (HK+) to the K+ form. There is an increase in the charge density from 1.0 C/ cm2 for the electrolyte in the HK+ form to 6.0 C/ cm 2 for the electrolyte in the K+ form. © 2010 The Electrochemical Society.

Journal of the Electrochemical Society

Perfluorosulfonic acid based electrochemical double-layer capacitor

Carbon

Effects of oxidation and heat treatment of acetylene blacks on their electrochemical double layer capacitances

Journal of Power Sources

Exfoliated graphite–ruthenium oxide composite electrodes for electrochemical supercapacitors

Electrical double layer supercapacitor is very significant in the field of electrical energy storage which can be the solution for the current revolution in the electronic devices like mobile phones, camera flashes which needs flexible and miniaturized energy storage device with all non-aqueous components. The multiwalled carbon nanotubes (MWNTs) have been synthesized by catalytic chemical vapor deposition technique over hydrogen decrepitated Mischmetal (Mm) based AB 3 alloy hydride. The polymer dispersed MWNTs have been obtained by insitu polymerization and the metal oxide/MWNTs were synthesized by sol-gel method. Morphological characterizations of polymer dispersed MWNTs have been carried out using scanning electron microscopy (SEM), transmission electron microscopy (TEM and HRTEM). An assymetric double supercapacitor stack has been fabricated using polymer/MWNTs and metal oxide/MWNTs coated over flexible carbon fabric as electrodes and nafion ® membrane as a solid electrolyte. Electrochemical performance of the supercapacitor stack has been investigated using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy.

Fulltext

Nanoscale Research Letters

Asymmetric flexible supercapacitor stack

Performance of EDLCs using Nafion and Nafion composites as electrolyte

Journal	Journal of Applied Electrochemistry
ISSN	0021891X
Open Access	No