Литиевые электрохимические системы

DOI: https://doi.org/10.18500/1608-4039-2018-18-3-113-121

This article discusses methodical approaches to diagnostics of the state of electrochemical objects including evaluation of the depth of discharge of chemical current sources. Techniques of experiments and software package for data collection and processing are described. The study is focused on identifying the acoustic spectroscopy parameters most closely related to the depth of discharge of chemical current sources.

The review of cathode materials for lithium-ion batteries is presented, the analysis of advantages and application prospects of cathode materials on the basis of lithiated transition metals oxides is carried out. A method of heterovalent modification by ions of highly negative elements, lanthanum and its analogues for improving the electrochemical indices and stability of lithium manganese spinel is proposed. The effectiveness of fullerene, lithium fluoride, fullerenes halogen derivatives as modifying additive for MnO₂ cathode materials has been noticed.

To model the characteristics of lithium-sulfur batteries based on the experimental evaluation of the electrochemical properties of electrode materials, the software "Battery Designer", included in the software package “ElChemLab”, was developed. The possibilities of software are described. The specific energy of lithium-sulfur batteries is compared for different surface capacitances of a positive electrode and for different amounts of electrolyte.

The influence of lithium-fluorocarbon glass leads on the stability and preservation, as well as the behavior of differentcurrent leads of insulator is studied. It is shown that the most resistant glass for lithium output is silicon-free glass C62. The behavior of the fluorocarbon cathode current lead (titanium, niobium, molybdenum-rhenium) during storage is investigated. Discovered high corrosion niobium current lead correlation between OCV element and the intensity of corrosion of niobium current lead.

Synthesis of electrode material based on Li₂MnSiO₄/С using widely used, environmentally safe and inexpensive Li, Si and Mn-containing precursors was considered. Mechanochemical activation was used for improving the flow of thesolid-state synthetic process and providing the necessary reactivity to obtain the target product with a high content of the main lithium-accumulating compound.Structural and morphological features of the composite were investigated by X-ray diffraction, laser diffraction granulometry.

Various strategies for the synthesis of promising electrode materials for lithium-ion battery (LIB) based on iron(II)-lithium orthosilicate (Li₂FeSiO₄) using widely distributed, environmentally friendly and inexpensive starting materials are considered. The materials obtained are multicomponent electroactive composites that include, in addition to the main lithium accumulating component, also auxiliary structure-forming and electrically conductive components based on the products of the pyrolytic decomposition of organic compounds.

This paper discusses the prospects for developing a cathode material based on the cobalt(II)-lithium vanadate(V) (LiCoVO₄) for a lithium-ion battery, an approach to its preparation and features of the electrochemical behavior.

For the purpose of creation of a reliable current conductor for fluorocarbon-lithium cell with use of the fast-tempered materials the corrosion and electrochemical behavior of microcrystalline AV-86 alloy and also amorphous Ni₈₁P₁₉ and Fe₇₀Cr₁₀P₁₃C₇ alloys in electrolytes on a basis ?-butyrolactone (GBL) is studied. The high corrosion resistance and conductivity of amorphous materials do perspective their use as current conductor of current sources.

Degradation of Na₂Ti₃O₇-based electrodes is studied by galvanostatic as well as electrochemical impedance spectroscopy methods. The rate of degradation was shown to decrease from cycle to cycle as the cycling progresses and also as the cycling current increases. It was concluded that the main reason of degradation is the gradual an electrolyte reduction with the formation of insoluble products (SEI).

Within the work, an influence of manganese dopant on electrochemical performance of anatase titanium dioxide (Mn/Ti = 0.05; 0.1; 0.2) had been investigated. It was established that incorporation of Mn³⁺ into the TiO₂ lattice results in the formation of Ti_{1 ? x}Mn_xO₂ solid solution and increased anatase unit cell volume from 136.41 A³ (undoped sample) to 137.25 A³ (Mn/Ti = 0.05). The conductivity of doped TiO₂ rises up to two orders in magnitude.