Supercapacitors

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.

The energy characteristics of prototypes of supercapacitors with carbon fabric electrodes Busofit T-040 were studied depending on the concentration of aqueous solutions of sulfate, sodium iodide and their mixtures without and in the presence of a corrosion inhibitor of the nickel collector – benzotriazole. It was found that the specific capacity of devices based on sodium iodide is almost two times higher than in the case using sulfate media. Close values of specific capacitance were obtained in devices based on mixed electrolytes.

The work is devoted to the study of the electrochemical characteristics of prototype energy storage devices made on the basis of electrodes consisting of titanium-modified graphite woven material “busofit”. It is shown that the modification increases the specific values of the capacitance and the magnitude of the operating voltage.

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.

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

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.

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

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.

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).