Электрохимические конденсаторы

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.

The influence of the pH value in the dispersions during washing the potassium polytitanate powder (PPT) after its molten salt synthesis on electrical properties of the obtained product, namely conductivity, permittivity and tangent of dielectric losses. It is established that the samples obtained in weakly alkaline conditions (pH = 7.44 and 8.50), are characterized by higher values of low-frequency conductivity and dielectric permittivity (up to 10^{5), low value of the relaxation time (0.112 and 0.358, respectively).

The present article considers work principle of lithium-ion capacitor (LIC) and methods of negative electrode pre-lithiation. The effect of application of different active materials of positive and negative electrodes, electrolyte and separator on the specific power and energy of LiC is shown.

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.

DOI: https://doi.org/10.18500/1608-4039-2017-17-4-225-234

DOI: https://doi.org/10.18500/1608-4039-2017-17-4-173-224

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.

A review of the current literature on hybrid supercapacitors (hybrid devices) in acid and alkaline electrolytes is presented.

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 electrochemical characteristics of electrodes based on various fibrous carbon materials (manufactured by OOO NPTs Uvikom) for hybrid supercapacitors C/PbO₂ with an acid electrolyte have been investigated. It is shown that the highest values of the capacitive characteristics of the electrodes were obtained using carbon activated felt UVIS-AK-V-170, characterized by capacities up to 400 F/g.