Электрохимические конденсаторы

The new materials obtained in the potassium polytitanate (PPT)–MnSO₄ system by modifying PPT in aqueous solutions of manganese sulfate of various concentrations, followed by thermal treatment and annealing at 1080°C, were synthesized and studied. The phase composition of the obtained materials was determined. Their electrochemical and electrophysical properties in the temperature range from 250 to 700°C were studied.

The electrochemical and electrophysical properties of the protonated and modified with silver iodide potassium titanates, which can be applied in energy storage units, have been investigated by impedance spectroscopy. It has been shown that the dielectric losses at medium and high frequencies are weakly dependent on the polarizing voltage. It has also been established that transfer in modified potassium titanate can be made through potassium and silver ions.

Poly(5-vinyl-2-methylpyridine) sulfurized with elemental sulfur at 140-320°C (sulfur content up to 45%) possess electric conductivity (6.4·10^-11-1.6·10^-7 S/cm), paramagnetism 6.2·10¹⁸–5.0·10¹⁹ sp/g, g = 2.0043-2.0046, AH = 0.49-0.58 mT), redox and complex-forming properties.

The automatic module device for cycling in galvanostatic regime with a wide range of charge/discharge current and measuring signals from electrochemical cells is developed. The software allowing governing the cycling processes and providing friendly interactive interface is written.

It was established one-, two and three-factor regression dependencies among discharge capacity С, short-circuit current I (SC), open circuit voltage U (OCV), internal resistance (R_i) and mass (m) for polynomials of a degree n(n = 1–4) in all sampling. The discharge capacity of ``fresh'' cell's forecasts a little bit better than after their long storage and magnitude of standard deviations for ``fresh'' CR2325 (2.5%) differ from ``old'' cells approximately twice (5.5%).

It is shown that the correlations of Romanov and Shepherd–Dasoyan are equivalent under description of discharge curves of alkaline accumulators in the interval of discharge voltages from the beginning to 1 V and any ones used for the particular accumulators of discharge currents. However under low discharge voltages the correlation of Shepherd–Dasoyan describes the direction of discharge curve correctly while the correlation of Romanov gives false results.

In present work the lithium diffusion was investigated to LiAl- and MnO₂-electrodes, modified by La. With this purpose Al and MnO₂ was worked up by cathodiе incorporation method in aprotic organic solutions of sulfanilate lanthanum. The next cyclization of electrodes to lithium perchlorate solution was making in potentiodynamic conditions.

With mathematical methods of description of macrokinetic processes in the volume of porous electrodes the investigation of influence of kinetic and structural characteristics of electrode-comprising materials to the process of current generation was performed. The nonuniformity of current generation distribution as well as the level of polarization loss are significantly determined by correlation of electric conduction values of solid phase components and electrolyte.

The relation between porous structure, electronic properties of carbonaceous material and the capacitance of its interface with an electrolyte is discussed. The sizes of the pores in which the processes of capacitive and pseudocapacitive charge accumulation dominate are determined.

Safety level of small commercial Lithium-Ion cells with LiCoO₂ as cathode material during overcharge was investigated. Conditions and possible mechanism of autocatalytic rise of temperature and pressure inside the battery were discussed.