supercapacitor

The electrical and chemical characteristics of nanocomposite materials based on carbon black for double-layer supercapacitors were investigated. It was shown that the highest values of the specific capacitive characteristics were obtained for carbon material SP4 which has the largest specific surface area (total capacity 228 F/g, reversible capacity 162 F/g).

In this paper we investigate carbon materials prepared from different organic raw materials of vegetable nature by the method of pyrolysis. Properties of obtained carbon substances are established by the methods of impedance spectroscopy, voltamperometry, and chronoamperometry. Starting from the data of electron paramagnetic resonance, impedance spectroscopy and an analysis of the Regon diagrams it is concluded that the obtained carbon materials contain carbon nanostructures in the form of bungles of multiwall nanotubes.

In the current paper electrospun nanofiber mats were derived from polyacrylonitrile (PAN). The temperature influence on the volumetric and surface composition of the resulting pyropolymers was studied by means of elemental analysis and X-ray photoelectron spectroscopy.

A various features of the electrochemical behavior of number superfine carbon materials in electrolyte based on an ionic liquid 1-methyl-3-butilimidazolium tetrafluorineborate (1Me3BuImBF4) were determined by voltammetry and impedance methods. A comparative analysis of the effect of the type and nature of the electrolyte material on the main electrochemical characteristics of carbon electrodes which may be used in supercapacitors was done.

This article show results of research work which focused on a new electrodes for symmetrical supercapacitor which made from electrochemically reduced graphene oxide films.

The recovery process illustrated by experimental recordings С-V curves. Was identified the dependence of the reduced graphene oxide specific capacity from rate of charge/discharge, for symmetric and unipolar working voltage range. Was identified supercapacitor power density when it was tested in cyclic charge-discharge duty of the potentiostat with different speeds.

This work is dedicated to phosphoric acid esters working as solvents for lithium-ion and supercapacitor (SC) electrolyte. The electrical conductivity of electrolytes based on phosphoric acid esters, lithium salts, commonly used in lithium-ion batteries (LIB), and salts used in SC technology was measured. The thermodynamic stability of new electrolytes in comparison with other solvents used in chemical power sources technology was also estimated. It was shown that the thermodynamic stability of phosphoric acid ester increases in a homologous series.

The electrochemical characteristics of the electrode material based on activated “NORIT B Test EUR” carbon in 1 M sodium sulfate solution were evaluated by cyclic voltammetry, galvanostatic charge-discharge curves, and impedance spectroscopy. It is established that this material has low resistance, and the specific capacity of the electrode was 45 F/g.

The cyclic voltammetry was used to study the behavior of a symmetric supercapacitor with activated carbon cloth electrodes and a solution of an ionic liquid (C₈H₁₅N₂PF₆) in freon-22 as an electrolyte in the temperature range from ? 140 to + 130°C. The measurements were carried out in a special autoclave. At temperatures above 90°C, the supercapacitor exhibits purely capacitive behavior, whereas at the temperature lowering, the influence of resistance strongly increases.

The results of the study of electrochemical dispersion of flake graphite in sulfuric acid were presented. It was shown that the highest dispersion efficiency was achieved while using large fractions of graphite with a particle size being more than 200 microns. The formation of the multilayer graphene oxide structures with the thickness of 0.1–1.0 microns and lateral dimensions up to 100 microns during anodic oxidation of graphite was established. The graphene structures were identified by the x-ray phase analysis and IR-Fourier spectroscopy.