ISSN 1608-4039 (Print)
ISSN 1680-9505 (Online)

Литиевые электрохимические системы

Some trends in improvement of cathode materials for lithium-ionic batteries

Major trends in cathode active material development for lithium-ion batteries have been reviewed. Statistics on all publications in «Journal of Power Sources» (from 03.2006 till 04.2007) is summarized in order to point out that the main effort in secondary batteries development is concentrated on lithium-ion batteries, especially on positive electrode study. Based on these publications the main routes for LiCoO2 modification as well as for novel materials research have been reviewed.

Electrodes of lithium-ion batteries: some simple method for diagnostics of degradation at cycling

It is shown that an examination of reduced galvanostatic charge-discharge curves allows making preliminary conclusion on degradation mechanism upon cycling. If such degradation is due to loss of active material all normalized curves coincide. In the case of insulating films building up normalized curves are shifted along potential axis. Various structure changes result in qualitative change of curves shape.

The lithium batteries based on the gidrolytic lignin

In this paper the possibility of applying of hydrolysis lignin as the lithium battery cathode material was demonstrated for the first time. Hydrolysis lignin features have been investigated by impedance spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Electrochemical characterization was carried out at room temperature using 1M LiBF4 in ?-butyrolacton electrolyte system. The chemical composition of cathode materials upon battery discharge down to 0.9 V was studied by the X-ray photoelectron spectroscopy and Infrared spectroscopy.

Dependence of the electrochemical characteristics of lithium-ion battery in the initial state and after Degradation of the structural parameters of the positive electrode

The study of the internal resistance of the lithium-ion battery designed and manufactured by JSC «Saturn» as the original, and after a long cycle life by pulse chronopotentiometry and electrochemical impedance was carried out. It is shown that the higher the hexagonal ordering of the material and the closer the degree of cation mixing to the optimal value, the less polarization resistance of the battery as original, and after a long cycle life. It was found that the less the original polarization resistance of the battery, the more its cyclic life.

Silicon electrodes degradation at cycling

On basis of analysis of literature data as well as of own experimental results we suggest some regularity for degradation of silicon electrodes upon cycling. It was shown that an electrode capacity Q at n-th cycle can be calculated from equation Q = Q0 exp(kn+?n2/2), where Q0 is initial capacity value, k и ? are empiric constants.

Behavior of a 150 A·h lithium-ionic battery in extreme situations

The brief review of the processes arising in Li-ion cells in the cases of abuse is presented. The results of tests on overcharge, overdischarge, short circuit inside the cell and external short circuit for Li-ion cell having capacity of 150 A·h are shown and discussed. The recommendations to minimize the aftergrowths are suggested.

Determination of residual capacity of lithium-fluorocarbon batteries for car-dioelectronics

A pulse method at which a tested chemical power source is discharged by a pulse generated by constant current of special shape, and voltage on a cell is measured before and after pulse action has been developed to determine the degree of dicharge of chemical power sources. The degree of dicharge of a chemical power source is determined using a specially developed algorithm from the values of these voltages and other electrical parameters calculated.

Research and diagnostics of the lithium power sources by the method of electrochemical noise. II

The problem of use discharge and noise characteristic of primary power sources system of thionyl chloride/lithium for definition of their operative conditions (first of all, depth of discharge) is considered. On the basis of the analysis of features of discharge curves of Li/SOCl2 cells both bobbin and wound (rolled) type, and also intensity of voltage fluctuations and power-density spectrum of electrochemical noise of above mentioned cells it is drawn a conclusion on an opportunity of carrying out their correct diagnostics.

Multichannel potentiostat-galvanostat for battery and electrochemical cells cycling

Multichannel instrument to study batteries and electrochemical cells during charge-discharge cycling, and open-circuit conditions is described. Each channel is a programmable potentiostat-galvanostat operating by an independent program. The accuracy of the stabilization current and potential is 0.01%. The additional sensors with analog output, such as temperature, can be plugged to each channel. The proposed hardware and software solution allows to control experiments, receive measurement data and remote administer the instrument via Ethernet.

Properties of LiFePO4-based cathode material with additions of conducting polymer for Li–ion batteries

In this study, the electrochemical behavior and properties of the novel LiFePO4-based composite cathode material with a water-soluble binder LA-133 and a conductive polymer PEDOT:PSS (poly-3,4-ethylenedioxythiophene: polystyrenesulfonate) as an aqueous dispersion were studied. Using the conductive polymer in combination with a water-soluble binder LA-133 allows to reduce the proportion of electrochemically inactive components (up to 10\%) and thus to increase its specific capacity for a given weight of the active material.