For the first time, the electrochemical behavior of sodium vanadium fluorophosphate-based electrodes in carbonate and diglyme electrolytes was compared. It was shown that a 1 M NaPF6 solution in diglyme can be successfully used in anode-free sodium batteries with sodium vanadium fluorophosphate-based cathodes.

The paper presents the results of a study on the distribution of lithium in a solid-state thin-film lithium-ion battery using the Rutherford backscattering spectrometry (RBS) method. The analysis employs He+ ions with an energy of 1.8 MeV, scattered at an angle of 165° with normal incidence to the surface. Based on the energy loss of scattered ions, we determine the concentration of Li ions in the battery layers in both charged and discharged states. The study shows that the Li-concentration values obtained through the RBS method and the galvanostatic-measurement method coincide, provided that the specific stopping cross section for lithium εLi in the anode layer is half of that in the single-element substance.

All-solid-state anode-free sodium batteries present a special and especially important kind of energy storage device. Unfortunately, the industrial production of such batteries has been absent up to now, although the prospects of their development seem to be rather optimistic. The present mini review considers the fundamental advantages of all-solid-state anode-free sodium batteries as well as challenges in their creation. The advantages of all-solid-state anode-free sodium batteries reveal themselves when comparing them with ordinary sodium-ion batteries, sodium metal batteries, sodium batteries with liquid electrolyte, and their lithium counterparts.

Cyclic voltammetry and gravimetry are used to study the behavior of a smooth gold electrode in a medium of bridged 1,2,4-trioxalane in acetonitrile. It is found that the peroxide bond in the molecule of bridged 1,2,4-trioxalane is reduced on the surface of the electrode during the cathodic process, with the subsequent formation of a diketone fragment. The formation of colloidal gold particles is detected during anodic oxidation.

It was shown for the first time that Ge–Co nanostructures can be formed on a copper substrate by electrochemical deposition. The nanostructures are globules, reaching 1 μm in size and consisting of smaller particles whose size does not exceed 10 nm. They demonstrate a sufficiently high reversible capacity of 850 mA h/g and good stability under long-term cycling.

The principal features of all-solid-state lithium-ion batteries and similar ones with a lithium metal electrode are reviewed. The main areas of application of such batteries are considered. Solid inorganic electrolytes and electrode materials are discussed in detail. The principal manufacturers are briefly listed.

The effect of a supporting salt in lithium-ion batteries upon the electrochemical performance of Ge-Co-In anodes was studied. The replacement of lithium difluoro(oxalate)borate (LiDFOB) for LiClO4 enhanced the discharge capacity at elevated C-rates because of a notable improvement in a solid electrolyte interphase (SEI), namely, a decrease in the resistance and thickness of the SEI formed in the LiDFOB electrolyte.

Atomic force microscopy, scanning electron microscopy, X-ray diffraction phase analysis, voltammetry, and chronopotentiometry are used to study the physicochemical properties of lead coating on steel substrates obtained galvanically. The effect the oxidized surface layer and through pores in the lead coating have on the coating’s function as an anode of chemical power sources is analyzed. It is shown that at positive temperatures, the anodic oxidation of the steel substrate can contribute to the functioning of the anode during a discharge. The high discharge characteristics of lead-coated anodes with no barrier layers on steel substrates at temperatures of −50 to +50°С are confirmed by tests of pilot batches of Pb/HClO4/PbO2 reserve power sources. The potential of using tin–lead alloy POS 63 on copper substrates to manufacture anodes for chemical power sources is demonstrated.

Bridged bicyclic peroxide with 1,2,4-dioxazolidine core, namely, ethyl 2-(4-chlorobenzyl)-1,5-dimethyl-6,7-dioxa-8-azabicyclo[3.2.1]octane-2-carboxylate, was studied by cyclic voltammetry in acetonitrile medium on a smooth gold electrode. During the cathode process, two electrons are transferred, with the first electron transfer being reversible; a mechanism of cathode reduction of the substrate involves acetonitrile as the source of protons. The anodic oxidation involves the formation of colloidal gold particles due to corrosion of the gold electrode. O O Me EtO Me Cl O Au + 2e-EtO O O O Me NH Cl-e-Au Au NPs

The electrochemical characteristics of solid-state thin-film lithium-ion batteries with two different structures: Ti/Anode/LiPON/LiCoO2/Ti (with an anode) and Ti/LiPON/LiCoO2/Ti (anode-free) are intercompared. Si@O@Al composite anode with thicknesses of 154 and 15 nm, as well as pre-lithiated LixSi@O@Al composite with a thickness of 192 nm, were used as anodes. In anode-free batteries, the lithium anode was formed by the in-situ method. Batteries with 154 nm-thick Si@O@Al and LixSi@O@Al anodes have good cyclability due to their moderate volume change during lithium-ion insertion/extraction and reliable adhesion to the LiPON solid electrolyte. These batteries are promising in terms of high energy density due to the lithium anode in-situ formation, although they have poor cycling performance due to peeling of the upper current collector. The introducing of a Si@O@Al thin film with a thickness of 15 nm between the LiPON and the current collector allows maintaining the high energy density that is inherent in batteries with lithium anodes, while also improving their cyclability.

Germanium-cobalt-indium (Ge-Co-In) nanostructures are a promising material for negative electrodes of lithium- ion batteries aimed for arctic exploitation. Electrochemical impedance spectroscopy was used for a detailed study of the interaction of Ge-Co-In nanostructures with lithium in a temperature range from -35 to +20 degrees C. The discharge capacity at temperatures of 20, 0, -10, -20, and -35 degrees C amounted to 1400, 1228, 1040, 907, and 793 mAh g-1, respectively. The impedance spectra measured at various lithiation degrees were found to differ but insignificantly whereas temperature variation resulted in notable changes in the spectra. A normalized charge transfer resistance for Ge-Co-In nanostructures was significantly (more than an order of magnitude) less than for Ge-In nanowires (obtained by the same method, but without the addition of cobalt salt into the electrolysis solution). It is this difference in charge transfer resistance that can explain the difference in the shapes of the impedance spectra for both objects. Also, in contrast to data for Ge-In nanowires, the dependences of the lithium diffusion coefficient in Ge-Co-In nanostructures on potential had a clearly defined minimum. The lithium diffusion coefficient in Ge-Co-In nanostructures slightly exceeded that in Ge-In nanowires, and the activation energy of lithium diffusion in Ge-Co-In nanostructures was marginally less than in Ge-In nanowires.

Electrochemical impedance spectroscopy was used to detailed study the interaction of Ge-Co-In nanostructures with lithium in a temperature range of ‒32 to +20 °C. The nanostructures were synthesized by electrodeposition from aqueous complex solutions of Ge (IV) and Co (II). Such nanostructures were described by slightly modernized equivalent circuit, including the resistance of the electrolyte (Rs), the resistance of the SEI (RSEI) shunted by an element with constant phase shift (CPESEI), the charge transfer resistance (Rct), shunted by CPEct, and the Warburg impedance (W). The impedance spectra measured at various lithiation degrees were found to differ but insignificantly whereas temperature variation resulted in notable change in the spectra. All room-temperature impedance spectra consist of high-frequency semicircle and low-frequency Warburg straight line. Temperature lowering is accompanied by some distortion and even degeneration of the semicircle, in contrast to features of Ge-In nanowires studied previously. Also, in contrast to data for Ge-In nanowires the dependences of the lithium diffusion coefficient in Ge-In-Co nanostructures on potential have a clearly defined minimum. The lithium diffusion coefficient in Ge-In-Co nanostructures slightly exceeds that in Ge-In nanowires, and activation energy of lithium diffusion in Ge-In-Co nanostructures is marginally less than in Ge-In nanowires.

The problem of fast charging of lithium-ion batteries is one of the key problems for the development of electric transport. This problem is multidisciplinary and is connected, on the one hand, with electrochemical current-producing processes and the features of lithium-ion batteries themselves, and on the other hand, with the charging infrastructure, the design of chargers, charging protocols, thermal management, battery management systems, etc. This review concerns the electrochemical aspects of fast charging keeping in mind that lithium-ion battery is a complicated and delicate system. Problems associated with positive and negative electrodes and electrolyte are considered separately.

The discharge of the zinc–perchloric acid–lead dioxide electrochemical system at temperatures from –50 to +50°C was studied. Zinc coatings, including those subjected to chromate passivation, can be used as anode materials for fast-activated reserve chemical power sources. The tests of pilot batches confirmed that the power sources met the activation time requirements (no more than 50 ms). The power sources of the given system are characterized by increased discharge voltage (the maximum voltage of one cell is 2.12–2.44 V) compared with that of the lead–perchloric acid–lead dioxide system (1.50–1.86 V). The disadvantages of the zinc–perchloric acid–lead dioxide system were revealed: instability of discharge characteristics and possible cell polarity reversal as a result of side reactions, which may have a significant negative impact on the reliability of reserve power sources.

Gallium phosphide (GaP) was synthesized and studied as an anode functional material for lithium-ion and sodium-ion batteries. Electrochemical interaction of GaP with lithium and sodium was compared. The reversible capacity of GaP toward lithium and sodium insertion was found to be about 760 and 465 mAh g–1, respectively.

In this work, a new cathode material for lithium-sulfur (Li-S) batteries was developed. Microporous carbon (with predominant pore size pound 1.2 nm) served as both a matrix for sulfur retention and conductive additive. Microporous carbon was shown to be capable of adsorbing lithium polysulfides thereby suppressing their migration toward lithium anode. The discharge capacity of the S/C composite at the 1 st and 20th th cycles in Li-S battery operation was 513 and 421 mAh g -1 at a scan rate of 0.1 mV s-1. -1 .

The electrochemical behavior of a flat gold electrode in an acetonitrile solution of 3-(1,4-dimethyl-2,3,5,6-tetraoxabicyclo[2.2.1]hept-7-yl)propanoic acid was studied by cyclic voltammetry. The formation of colloidal gold particles was detected during the anodic oxidation. The kinetics of their formation was studied by the gravimetric method. Peroxide bonds in the cyclic peroxide molecule were found to be reduced on the cathode surface with the subsequent formation of the diketone fragment.

Two new electrochemical systems have been developed for sodium-ion batteries with a positive electrode based on manganese-doped sodium iron phosphate (NaFe0.5Mn0.5PO4) and a negative electrode based on a CoGe2P0.1 nanostructure, as well as with a positive electrode based on iron-doped sodium vanadophosphate (Na3V1.9Fe0.1(PO4)3) and a negative electrode based on a CoGe2P0.1 nanostructure. The results of cycling of battery models showed that the energy density of the NaFe0.5Mn0.5PO4/CoGe2P0.1 and Na3V1.9Fe0.1(PO4)3/CoGe2P0.1 electrochemical systems is 165 and 167 W h/kg, respectively.

The purpose of this research is to improve the performance and reduce the activation time of reserve power sources based on lead-acid systems at lower temperatures, down to –50 °C. Physico-chemical factors affecting the activation speed of reserve power sources based on Pb–HClO4–PbO2 and Zn–HClO4–PbO2 systems are investigated using chronopotentiometry, scanning electron microscopy, and standard contact porosimetry. Two approaches to the improvement of the low-temperature performance of power sources are used. The first one is based on the substitution of lead as anodic material with zinc. This allows the increase in discharge voltage and simultaneous decrease in activation time, but brings about the instability of discharge characteristics and, finally, deteriorates the reliability of power sources. The second approach is based on the use of PbO2 cathode material with enhanced nanoporosity. The chronopotentiometric method in galvanostatic mode is applied to the quality estimation of cathodes. The criterion of applicability of cathodes for reserve power sources consists in the low discharge overvoltage (0.1–0.2 V). Efficient performance of reserve power sources possessing the stable discharge voltage (1.5–1.8 V per cell) and the unprecedentedly short activation time (under 30 ms) even at lower temperatures (down to –50 °C) is achieved. The results are verified by fabrication and testing of pilot batches of miniaturized reserve power sources having microcells’ volume of 0.02 ml. The second approach to the improvement of power sources is transferred into the industrial production.