Электрохимические конденсаторы

The work is devoted to investigation of the anisotropy of conductivity and determination of the most likely charge carriers in the amorphous polytitanate potassium. Defined ac – and dc-conductivity, dielectric permittivity, dielectric loss tangent in mutually perpendicular directions compacted potassium polytitanate.
An increase in the shift of the peak and the dielectric loss tangent in a frequency region when measured along the preferred direction location lamellae potassium polytitanate.

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.

In the temperature range from 25 to 100 °C, the behavior of the conductivity and the electrical characteristics of potassium polytitanate modified iron sulfate at a pH modifying solution from 2.0 to 9.0. The temperature dependence of ac-conductivity, permittivity, conductivity activation energy evaluated.

The phase composition, thermal coefficient of linear expansions (TCLE) and electrical conductivity of (PrXLa1-X)1.85Sr0.15Ni0.9Сu0.1O4 (X=0.0; 0.1; 0.5; 0.9 и 1) (X=0.0; 0.1; 0.5; 0.9 and 1), Pr1-YSrYNiO4 (Y= 0.0; 0.05; 0.1; 0.15; 0.16 and 0.2) and Pr1.84Sr0.16Ni1-ZCuZО4 (Z=0.0; 0.1; 0.5 and 1) are investigated at air in the temperature range 100–1000 °C.The thermal coefficient of linear expansion of (Pr1-XLaX)2-YSrYNi1-ZCuZO4 are in range of (11.6–16.3) 10-6 deg-1 and depends on the size and type of addition.

The behavior of the conductivity and of electrophysical characteristics of potassium polytitanate modified by cobalt (II) sulphate was investigated under the temperature from 100 to 800 °C. The temperature dependence of AC and DC-conductivity was found, activation energy was appreciated in the low and high temperature phases. A equivalent circuit describing the transport processes in the studied composite based on potassium polytitanate was proposed.-

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: 10.18500/1608-4039-2015-15-4-160-166

Behavior of electrodes based on activated carbon P2 (Ener G2) wih additions of plain carbon black, as well as carbon black doped with silver nanoparticles have been studied. Depending on potential range and polarization direction the electrodes were found to reveal a capacitance close to double-layer or pseudocapacitance.