Литиевые электрохимические системы

The protective properties of the coating applied to the surface of lithium-manganese spinel (LiMn2O4), using the eutectic composition of Li2O : B2O3 = 47 : 53 (wt.) with the melting point of 650°C, were studied. The content of the eutectic lithium borate varied from 1% to 10%. The electrochemical behavior of the obtained materials in the cathode half-cells of lithium-ion battery was studied at room temperature.

An approach for constructing mathematical models of the current dependence of the capacity of electrode materials is proposed. The approach involves analyzing the probabilities of favorable and unfavorable events occurring on the elements of electrical equivalent circuits that can be used to model the electrode. Several probabilistic models that correspond to different combinations of a capacitor, a Warburg element and a constant phase element in an electrical circuit are proposed.

Nowadays, the active search for an anode material, which can be used in lithium-ion current sources, takes place. The potential anode materials are transition metal oxides (SnO₂, NiO and others). In this work, submicron NiO powder was obtained using the thermal decomposition of Ni(CH₃COO)₂⋅4H₂O. Besides, a NiO/C composite anode was fabricated and its behavior in the anode half-cell of lithium-ion current source was studied during multiple cycling.

Compositions of ultrafine Si and C particles are promising anode materials for lithium-ion power sources with improved energy characteristics. In the work, samples of lithium-ion power sources with an anode made of ultrafine SiC fibers, as well as mixtures of SiC fibers with graphite (C/SiC) and electrolytically deposited submicron silicon fibers (C/Si/SiC) were fabricated and studied for energy characteristics.

The effect of the structure and the specific surface area of carbon materials, contained in positive electrodes, on the peculiarities of cycling of lithium-sulfur cells (the depth of electrochemical reduction of sulfur and lithium polysulfides, the changes in capacity and Coulomb efficiency of cycling) was studied.

Characterization by in situ or operando methods is very important to deeper understand the chemical and electrochemical processes, as well as the degradation processes that occur during the operation of a lithium-ion battery.

Doped lithium titanate is known to be able to reversibly cycle in the potential range from 3 to 0.01 V and this ability depends both on the nature of the dopant and the doping level. In this work Li₄Ti₅O₁₂ samples doped with Nd in the amount of 0.5 to 2.0% were studied. It was shown that while being cycled in the extended potential range, the samples with the doping level from 0.5 to 1.0% demonstrated the highest capacity.