Silicon and silicon oxide compounds SiO, SiO2, SiOx and SiOC are considered as a promising family of materials for high-energy lithium batteries due to their high theoretical capacity, widespread in nature, low cost, environmental safety and ease of synthesis. Silicon oxide compounds have replaced silicon in the hope of improving the discharge characteristics of lithium batteries. Oxides of silicon show excellent stability during cycling after structure optimization. However, they suffer from the problem of low Coulomb efficiency and high voltage hysteresis (difference in charge and discharge voltage), which prevents their practical application. Significant bulk expansion of silicon oxides during cycling and irreversible loss of capacity in the initial cycles are an obstacle to their large-scale practical use. This review pays attention to the peculiarities of the conversion of SiO2 and its hybrid compounds into the redox reaction with lithium and ways to overcome existing problems. Silicon dioxide is more resistant to bulk expansion than silicon. Various structural formats of nanometer SiO2 have been developed and tested for lithium batteries, such as nanotubes, nanorods, nanowires, nanoparticles, thin films. To solve problems in the SiO2/Li system, a number of SiO2 composites with carbon, graphene, active and inactive metals, etc. have also been proposed and studied. Analyzing the results of the studies, we found a significant role of the solid electrolyte interphase film in the efficient conversion of SiO2. In turn, the formation of a film on silicon dioxide depends on the method of synthesis of dioxide, which introduces impurities into the final synthesis product. Impurities contribute to the distortion of the solid electrolyte interphase film during the cycling of the SiO2/Li system, and the loss of discharge capacity. SiO2 dioxide obtained in a dry environment of a ball mill differs favorably from that obtained from solutions. Many efforts have been made to overcome the problems in Si-containing electrode materials, however, they have to go a certain way for large-scale practical application.

In this work, we explored the possibilities of network thermodynamics to determine the most important kinetic parameter of the diffusion process, the diffusion coefficient of lithium ions (D Li ) in iron sulfide. Iron sulfides have been electrolytically synthesized in thin aluminum-based layers for implementation in miniature lithium batteries. A comparison is made of the results obtained by the method of network thermodynamics and the method of potentiostatic pulse titration PITT. The theoretical aspects of both methods are presented. The task was reduced to obtaining curves I (current) - time (t), their analysis and calculation of coefficient values (D Li ), using the theoretical foundations of diffusion and the methods used. At the early stages of applying the method of network thermodynamics to the study of diffusion in lithium current sources, it was not clear why the method is suitable for determining D Li not in the entire working range of potentials. A wide range of studies using the PITT method helps to answer questions related to the application of the network thermodynamic method. When using both methods, it is important to establish the potential range with diffusion kinetics and to reveal the accompanying electrode processes. Thus, it was found that both methods used are unable to provide reliable results in the Fe x S y electrode potential range of 2.8–1.8 V, since the diffusion nature of the electrode process is not a priority in this potential range.

The article presents some new results of the studies of corrosion processes in lithium battery systems with non-aqueous electrolytes. The following processes are considered: electrochemical corrosion of positive and negative electrodes, corrosion of structural materials, and electrochemical and chemical decomposition of non-aqueous electrolytes, which occurs simultaneously with the main electrochemical process. The main attention is paid to the role of corrosion processes on current collectors of current sources. Corrosion processes on aluminum current collector and stainless steel current collector for positive electrodes of lithium batteries are particularly considered. An important role of corrosion in the degradation of the lithium battery is emphasized. Case studies on corrosion in positive electrodes and lithium electrode are mentioned. Considerable attention is paid to the contact corrosion in aircraft, with an emphasis on the need for further studies of this process. The proposed corrosion mechanisms are considered.

Heterogeneous vanadium oxide compounds (bronzes and vanadates) attract designers of lithium-ion batteries due to their superior structural integrity in a redox reaction with lithium compared to V2O5, a standard intercalation electrode material for lithium-ion batteries. The structural stability favors improved discharge behavior of lithium-ion batteries based on potassium- and sodium-containing vanadium oxide compounds. We investigate the effect that the copresence of potassium and sodium ions has on the electrochemical transformation of vanadium oxide compounds in electrodes for rechargeable lithium-ion batteries. Results of X-ray diffraction analysis suggest that dispersed precipitates deposited at the anode depend on the electrolyte composition. The precipitates containing the vanadates Na5V12O32 and KV5O13 are formed in potassium metavanadate solutions containing sodium ions, and the vanadates Na10V24O64 and KV5O13 are formed in vanadyl sulfate solutions containing potassium and sodium ions. The evaluation of electrochemical behavior of the synthesized material suggests that it has potential for use in lithium-ion batteries. The vanadates prepared in vanadyl sulfate solutions and incorporated in thin-layer matrix-free electrodes of a lithium battery display superior cycling efficiency compared to V2O5. Implementations of thin-layer lithium batteries based on the Na,K–vanadium oxide compound synthesized in vanadyl sulfate solution may benefit from the positive effect resulting from the copresence of potassium and sodium.

behavior of a thin-layer Co 9 S 8 in redox reactions with

V2O5 thin layers are electrodeposited on a stainless steel (Type 18N12Kh9T) anode from an aqueous metavanadate solution. The oxide deposits are subjected to thermal treatment at 300 or 500°C and tested in a redox reaction with lithium. The findings are compared to the behavior of similar deposits obtained from a vanadium oxysulfate solution. The use of prepared deposits in thin-film lithium batteries is discussed. The physicochemical and structural properties and surface morphology of synthesized materials are investigated using X-ray diffraction, IR absorption spectroscopy, atomic force microscopy, and thermal analysis. In comparison to coarse-grain deposits obtained in metavanadate solutions, deposits formed in vanadium oxysulfate solutions exhibit better adhesion to a substrate due to their branched structure. To use the V2O5 deposited from metavanadate solution in lithium batteries, new ways for modification of the deposit surface morphology must be developed. The coarse-grain structure of V2O5 can be broken if electrodeposition is carried out in the presence of Co2+ ions.

The reasons for the fall in the discharge capacity of the LiMn2O4 spinel composition with a Norit carbon filler in the redox reaction with lithium at a temperature of 271 K were analyzed using cyclic voltammetry and impedance spectroscopy. A comparison is made between the electrochemical behavior of LiMn2O4–Norit compositions, LiMn2O4 compositions with carbon nanotubes, and LiMn2O4 compositions with natural EUZ–M graphite to identify the key factors responsible for the efficient transformation of the composite electrodes under study in the prototype lithium battery.

Electrochemically synthesized thin-layer NiS electrodes were studied in lithium perchlorate dissolved in 1.3-dioxolane or in a mixture of 1.3-dioxolane and tetrahydrofuran. In the 1.3-dioxolane 1 M LiClO4 electrolyte, the irreversible capacity was reduced by 20% сompared to the initial capacity. However, the stability of the electrochemical characteristics of NiS electrodes in redox reactions with lithium is unsatisfactory. Much better results of charge–discharge cycling of NiS electrodes were obtained in the electrolyte solutions of 1.3-dioxolane, tetrahydrofuran, and 1 M LiClO4 demonstrating a stable reversible capacity of 400–450 mAh/g during 50–75 cycles. Using the methods of electron microscopy and IR spectroscopy with Fourier transform, it was established that the reason for the discharge capacity fading of NiS electrodes was associated with the formation of a surface film, which reduces the adhesion and cohesion of NiS particles. This, in turn, leads to a loss in the mechanical strength of NiS electrodes.

ÒÎÍÊÎØÀÐβ ÅËÅÊÒÐÎÄÈ, ÂÈÃÎÒÎÂËÅͲ Ç ÏÐÈÐÎÄÍÎÃÎ FeS 2 -ϲÐÈÒÓ ² ÅËÅÊÒÐÎ˲ÒÈ×ÍÎ ÑÈÍÒÅÇÎÂÀÍÎÃÎ FeS 2 ÊÎÌÏÎÇÈÒÓ, ÄËß ÂÈÊÎÐÈÑÒÀÍÍß Â Ë²Ò²ªÂÎÌÓ ÀÊÓÌÓËßÒÎв ÄÂÍÇ «Óêðà¿íñüêèé äåðaeàâíèé õ³ì³êî-òåõíîëîã³÷íèé óí³âåðñèòåò», ì.Äí³ïðî, Óêðà¿íà Âèÿâëåíî, ùî ïðèðîäíèé FeS 2 -ï³ðèò áåç äîì³øîê åëåêòðîí

It was established that the number of active sites for the insertion/extraction of lithium ions in/from the V2O5 structure in EC-DMC/Li-salt solutions depends on superhalogen anion. Unstable sites and their dependence on superhalogen anion (PF6–, AsF6–, ClO4–) are identified during discharge-charge cycling of V2O5 electrodes. The number of open sites in V2O5 depends on the structure stability and conductivity of V2O5. To increase the structure stability in phase transitions, we propose the electrochemical doping of V2O5 by Mn2+. We propose that the conductivity and rate characteristics of V2O5 could be increased by its co-deposition with conducting polymer of polyaniline type. Using theoretical calculation simulations assumptions have been made regarding the difference in the solvation of lithium ions in an EC/DMC mixture with different ratios of the solvents.

V2O5 is known as inexpensive, high energy, environmental secure the electrode material in lithium accumulators. The loss of discharge capacity at cycling due to structure degradation of crystal lattice V2O5 is one from the deterrent for expanded production of Li/V2O5 accumulators. For improvement of stability of V2O5cycling, obtained electrochemically V2O5-X·yH2O oxides were doped by argentum using ion-exchanging method with following their annealing. Synthesized argentum vanadate's in the electrodes for lithium accumulator show raised discharge capacity and stability in comparison with those of V2O5.

Magnesium battery is considered as an alternative to more expensive and environmentally unsafe lithium battery. New strategy proposes for practical magnesium system according to which the high energy and current density are achieved due to surface redox reactions and capacitive non-Faraday processes. This strategy was successful in nanometer anode material Mn3O4. In the paper, the electrode material (Mn3O4, Mn2O3) with the particles above submicron level in a composition with a carbon filler Norit was synthesized and investigated as less harmful to human health. A comparison of (Mn3O4, Mn2O3, Norit) characteristics is performed in cell with magnesium- and lithium perchlorate electrolytes based on glymes. The possibility was shown and the electrochemical reformation conditions of (Mn3O4, Mn2O3, Norit) are determinate in magnesium electrolytes to obtain a capacity of the order of 200 mAh.g(-1). The start lithiation capacity of (Mn3O4, Mn2O3, Norit) reaches to 980 mAh.g(-1) in lithium perchlorate electrolyte, whereas delithiation capacity is reduced to 250-300 mAh.g(-1). The Norit carbon material is an electrically conductive additive, but it is also electrochemically active in magnesium electrolyte. However, the rate and capacitive characteristics of (Mn3O4, Mn2O3, Norit) limited by the size of the particles of the thermal synthesized low-conducting Mn3O4, Mn2O3 oxides. The problem of using Mn3O4 in high energy magnesium battery capable of replacing lithium battery is discussed. For the replacing, magnesium non-aqueous electrolyte is needed with wide window of electrochemical stability for Mn3O4-anode compatible also with high voltage cathode materials.

Silicon dioxide has been produced by deposition from an aqueous solution of Na2SiО3 · mH2O. The particle size of the main faction of the synthesized material determined using an electron microscope ranges from 12 to 16 nm. According to XRD phase analysis, an amorphous modification of silicon dioxide has been obtained. It was then used to synthesize a thin-layer SiO2/Ni composite via electrolysis to determine the possibility of using it in the negative electrodes of miniature LIBs (LIBs). Studies of the SiO2/Ni composite in a prototyping lithium-ion battery in the galvanostatic mode have shown stable cycling in the voltage range from 0.40 to 0.15 V indicating promising usage in LIBs.

The analysis of electrochemical and impedance characteristics of thin-layer composite LiMn2O4 spinel, carbon nanotubes (CNT)-electrodes in redox reaction with lithium was provided to gain a better discharge characteristics at long cycling and low temperature. The comparison of parameters of impedance spectra (IS) for LiMn2O4, CNT-electrodes in contact with electrolyte and also conductivity of pressed LiMn2O4 spinel, its pressed composites with CNT and electro conductivity of electrolyte (1 mole-l LiClO4, ethylencarbonate, dimethylcarbonate) on dependence temperature and composite mass was performed. It was established undoubted contribution of transfer processes in Solid electrolyte interface (SEI) film of composite, electro conductivity of composite in efficiency of electrochemical performance of spinel composite at low temperatures. Activation energy of Li+-diffusion in LiMn2O4 composite volume exceeds one of migration of ions in SEI film and of charge transfer through phase boundary at room temperatures. Key role in decreasing of discharge characteristics of LiMn2O4 spinel composition with CNT at low temperatures and long cycling due to charge transfer through SEI film /spinel composite interface complicated by diffusion Li+ in composite volume which resistance rises in the most extensively measure than other parameters. Electrolyte of 1 mole l-1 LiClO4, ethylencarbonate, dimethylcarbonate is not recommended use for effective performance of LiMn2O4 spinel, CNT-composite in redox reaction with lithium at low temperatures and it is need its substitution. Improvement of low temperature discharge characteristic of spinal composite in further may be attaining by optimization of its perspective Co-doping.

The efficiency of using in a lithium battery transition metal sulfides electroplated on a metal support strongly depends on the kind and relief of the support. To make the nickel support rougher for enhancing the adhesion of sulfides, it was electroplated with a nickel–carbon composite, NiC. The discharge capacity and the efficiency of cycling of iron and cobalt sulfides electroplated with a NiC sublayer were higher than in the case when the sulfides were electroplated on a smooth nickel support without composite coating.

Conductive fillers play an essential role in the efficiency of the electrochemical performance of semiconducting LiMn2O4 spinel in a lithium accumulator. In this study, in order to improve the discharge characteristics of LiMn2O4 spinel in a thin-layer electrode, a Norit carbon filler with a submicron particle size was used as a filler. The composition of spinel with this filler ensures a discharge capacity of more than 100 mA h/g at a high discharge rate (more than 10 C) in the redox reaction with lithium in EC, DMC, 1MLiClO(4) electrolytes. Decrease of capacity takes place after the 200th cycle. The causes of this decrease upon cycling and at lower temperatures were analyzed via the impedance spectroscopy method. The efficient resistance of the charge transfer through the spinel composite electrode/electrolyte interface and the diffu-sion of Li+ play key roles in the degradation processes in the intercalation/deintercalation of Li ions into/from the spinel composite.

Purposeful synthesis of iron sulfide FeS2 films for a lithium battery were purposefully synthesized on a 18N12Kh9T steel cathode from a solution containing Mohr’s salt and Na2S2O3. Various aspects of synthesis were studied. Thin-film Fe-sulfide synthesis products were tested in a prototype lithium battery and also in a lithium-ion system. The synthesized electrolytic iron sulfide FeS2 with a marcasite structure is capable of reversible electrochemical transformation with output of 390 mA h g−1 in negative electrodes of the lithium-ion system with a LiMn2O4 counter electrode.

In order to obtain Co-doped LiMn2O4, high-temperature synthesis was used. Co-doping increases the conductivity of spinel, being in form of extruded pellet, at the temperature of 293 and 323 K. The advantage of compositions of Co-doped LiMn2O4 spinel with MCNT over pure LiMn2O4 lies in the increase of cycling efficiency and the rate of intercalation/deintercalation processes of lithium ions in thin-layer electrodes. At the discharge rate of 30-40 C the discharge capacity of (Co)LiMn2O4 in composition with MCNT is 80% of those obtained at the rate of 1 C. The reasons of the decrease in discharge capacity of composition of Co-doped LiMn2O4 spinel with MCNT in redox reaction with lithium at continuous galvanostatic cycling and reduced temperature were shown. On the basis of the analyses of system impedance spectrum, the composition of Co-doped LiMn2O4 spinel with MCNT/(EC, DMC, 1 M LiClO4)-electrolyte, the key role of charge-transfer resistance through composition/electrolyte surface was defined as well as degradation factors of particular stages of redox reaction of lithium with spinel composition.