Lithium electrochemical systems

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.

The relationship between the structural parameters of layered materials such as \alpha -NaFeO2 used as positive electrode materials of lithium-ion battery, and electrochemical characteristics were investigated. The dependence of charge transfer resistance on the ratio of cobalt to lithium mole fractions in layered oxides was studied.

The effect of 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF4) and 1-butyl-3-methylimidazolium tetrafluoroborate (BMIBF4) ionic liquids on the properties of the polymer electrolyte based on polyethylene glycol diacrylate (PEG-DA) and LiBF4 salt was studied. Research was carried out by spray-mass spectroscopy, differential scanning calorimetry, and electrochemical impedance spectroscopy technique in the temperature range from -40 to 120 °C.

Cite measuring result spectrum impedance of poly crystalline samples Mg-rcplacc lithium-iron spinel structure Li0 5l;c24Mg01O4 in the frequency range И>2 105 Hz in temperature range 295 723K. Displayed, that conduct temperature dependence real part of dielectric conductivity from temperature affirm about process activation electron transition between ions of iron varied valence and accompany reorientation dipole in variable field.
At high temperatures (T> 573K) make apparent dominating contribution of electro conductivity on direct current. Activation energy of conductivity in low (295 473K) and high (473 723K) temperatures region put accordingly 0.3 and 0.4 eV. Distinction value activation energy grows with increase frequencies and form on a frequency./ 105 Hz -55%. Такса research components complex electrical module of dielectric polarization, enabling division electronic and ionic part of conductivity.

The influence of rare earth elements nature on Mn02 electrode electrochemical modification process in solutions of their salts in aprolic organic solvents was investigated. It was proved that periodicity of properties inherent in the lanthanides lakes place in the products of their interactions with MnO, and it is connected with characteristics of their structure. It was shown that the choice of metal as a modifying agent may be decisive in choosing the conditions of synthesis of cathode materials.

Specific capacity of secondary batteries with thin-film electrodes have been estimated. Notable gain in specific capacity is shown to be possible only at substitution of the both electrodes with higher capacity for traditional ones.

Thin-film amorphous silicon electrodes, subjected to various pretreatment have been tested in galvanostatic and potenciodynamic modes. Preliminary heat treatment of silicon electrodes in nitrogen atmosphere was established to lead to some decrease in discharge capacity and insignificant decrease in degradation upon cycling. Preliminary annealing of silicon electrodes in vacuum at 480°C results in increase of discharge capacity and some decrease of degradation upon cycling. Silicon electrodes with thickness about 1 micron annealed in vacuum have discharge capacity about 1200 mA·h/g.

This paper describes the state-of-the-art and areas of application for lithium-ion batteries. Their competitiveness in comparison with conventional alkaline and acid based batteries is shown. System approaches and circuit configurations used for designing high-capacity energy storage batteries with microprocessor battery managemmt systems (BMS) are considered, including the main functions of BMS. Based on the given examples, the modular design approach of batteries with 2-3 levels of control has been proved. A comparative analysis of different hardware schemes for voltage leveling in storage batteries is carried out.

Cell with electrochemical system «lithium – fluorinated carbon» intended for electrical pacemakers have been developed. Their significant advantages over traditional lithium – iodine cells for pacemakers are shown. Discharges characteristics, a shelf-life, and reliability, as well as an effect of various additives in fluorinated carbon cathode on discharge characteristics have been studied.

The electrode behavior of various fluorinated graphite materials and different conductive additives in various electrolytes are studied. Fluorocarbon materials based on graphite fibers are shown to have the best discharge characteristics. The advantage of thin cathodes based on fluorinated nanomaterials with a solid polymer electrolyte in comparison with the similar electrodes with traditional fluorocarbon active material is demonstrated. The use of fluorinated nanomaterials results in increased discharge characteristics of the cells.