The work is devoted to the development of scientific principles for the creation of high-capacity conversion electrodes of the I type and highly reversible conversion electrodes of the II type with a large loading capacity and the construction of new "formulas" of liquid organic electrolytes (LOE), which provide the formation of mechanically strong and elastic, chemically and electrochemically stable, insoluble, dense and thin solid electrolyte interphase with unipolar Li+-conductivity and high adhesion to the electrode surface. It is shown that the use of trinity is the basis of a systematic approach in the selection of effective materials and optimization of physicochemical processes with their participation, taking into account the relationship of components and interdependence of electrochemical parameters of electrodes, and is the key to creating high energy and powerful lithium power sources (LPS). The principles of management of such processes are formulated and ways of practical use of the executed developments are offered.
A reversible Li-electrode with a modified superstoichiometric alloy Li1+xAl surface is obtained and characterized, effective electrically conductive ceramic 3D-composites with high nano-silicon content are synthesized, which are based on the idea of controlling their features at atomic, nano- and macro-levels, combined in a "carbon–carbon" composite advantages of highly crystalline and highly dispersed carbons, environmentally friendly polymeric binders based on water are used, which promote the formation of strong bonds of active materials with current collector, proposed replacement of the anode from graphite deposited on copper foil by Al-foil not only to increase the specific energy of lithium–ion batteries (LIBs), but also to significantly reduce the cost and simplify their manufacture, developed effective compositions of aprotic electrolytes for primary and secondary LPS.
The limits of application of lithium metal simultaneously as a reference electrode and an auxiliary electrode in half-cells are established. It is shown that the formation of dendritic lithium during electrodeposition is an inevitable process, despite the nature of the electrolyte and current density. New criteria that do not depend on the plating-stripping current of lithium are proposed to adequately describe the experimental data and reflect the physical nature of the processes during its cycling.
The proposed new criteria for cycling the lithium electrode are convenient for rapid analysis of the effects of impurities in the electrolyte that cause lithium corrosion. The limitation of the use of lithium metal simultaneously as a reference electrode and an auxiliary electrode in half-cells is established. It is proposed to place Al-foil on lithium so that its surface is enriched in situ with a superstoichiometric alloy Li1+xAl. Such an electrode has a low polarization resistance and a homogeneous plating-stripping of lithium is observed on it.
For the first time it is proposed to form a free volume of LOE in the cathode space of 1.5 V-cells of the system Li || CuO, which allows: to increase the volume of lithium in the anode and the mass of the cathode (reducing its porosity); avoid increasing the internal resistance of the elements until the end of the discharge; to reduce the time of output voltage of the cells to an acceptable operating level; reduce the swelling of the cells to acceptable limits. For the first time, a new design of 1.5 V-cells of the Li || CuO system was proposed for direct replacement of cells of the Zn || HgO system.
A reliable express-method of quantitative assessment of the influence of active materials and binders of electrode layer, as well as electrolyte components on the service life of LIBs has been developed. For this purpose, it is proposed to perform coulometric measurements on laboratory half-cells with high accuracy and to calculate the value of the accumulated irreversible capacity Qairr (n) as a key characteristic parameter. With this approach, there is no need to conduct research using the equipment needed to manufacture commercial LIBs.
The "carbon–carbon" composite combines the advantages of highly crystalline and highly disordered carbons, high-performance non-porous ceramic 3D-composites of 0D- and 2D-silicon with carbon-enriched silicon oxycarbide were synthesized for the first time.
Key words: intercalation, conversion mechanisms, liquid organic electrolytes, electrolyte additives, metallic lithium, aluminum foil, synthetic graphites, polymer binders, carbon-rich silicon oxycarbide, 0D- and 2D-nanosilicon, silanol functional groups, ceramic 3D silicon composites, solid electrolyte interphase, side reactions, electrode reversibility, accumulated irreversible capacity, lithium–ion batteries, primary lithium cells.
