импеданс

We have studied the capacitance and kinetic properties of nanoporous carbon material which was obtained from wood. The maximum radius pore distribution of the investigated material was 1.37 nm. The data from X-ray scattering and electrochemical impedance spectroscopy was used to investigate the influence of porous structure change and electronic structure of activated carbon material on the mechanism and kinetics of charge-discharge at 7.6m KOH solution. It was proved that depending on the electrode potential and chemical potentials of electrolyte ions there are two different mechanisms of the charge of the porous structure of investigated material. The first mechanism is a process of electrostatic adsorption of hydrated electrolyte ions, and the second is a process electrosorption of H+ or OH. It was shown the cycle of charge-discharge capacity of 95 F/g can be made for two seconds and this is half of the maximum capacity of the material under study.

In this paper, we investigated the possibility of determining the internal resistance of the battery by pulsed method with followed Fourier transformation in transition characteristics. The changes of internal resistance of lithium sulfur cells were studied in dependence on the discharge and charge depths during continuous cycling by proposed method. It was shown that the internal resistance of lithium sulfur cell was maximal at the point corresponding to the transition between high-voltage and low-voltage plateaus both at the charge curves and at the discharge curves. The most significant increase in the internal resistance of lithium sulfur cells occurs at the initial stages of cycling. It was found that the internal resistance of lithium sulphur cell is governed by the way the state of charge is achieved. This is due to the difference in densities of products, generated in positive electrodes by electrochemical reactions at charge (ρ(S) = 2.07 g/cm³) and discharge (ρ(Li₂S) = 1.63 g/cm³).