Russian Journal of Electrochemistry最新文献

Using polyethylene glycol (PEG) as stabilizer to control particle size, an easy-accessible PEG-assisted solid-state process is successfully developed. The method mainly involves ball-milling and sintering processes, so it is very suitable for scale-up production. Through systematic characterization, it has been found that the morphology and the particle size (less than 100 nm) of the cubic MnO are indeed successfully controlled. The galvanostatic charge/discharge tests show that the acquired MnO sample exhibits a high initial coulombic efficiency around 72%, a good cyclic performance (the capacity retention about 90% after 50 cycles) and an improved rate capability. The electrochemical performance improvements are mainly due to the reasons as following: the smaller particles and higher specific surface area can shorten the pathway for Li⁺ and electron transport; better structure is positive for reducing irreversible capacity loss; nanostructure can partly accommodate the strains of Li ion intercalation/de-intercalation.

Ti₃C₂T_x MXene has been actively studied as a promising energy storage material. In this paper, Ti₃C₂T_x MXene was prepared by selective removal of Al from Ti₃AlC₂ structure and then composited with graphene oxide (GO) to further improve the performance of Ti₃C₂T_x MXene. The as-prepared samples were characterized by using SEM and XRD techniques. SEM images of the Ti₃C₂T_x MXene exhibits a typical accordion-like morphology after removal of Al from Ti₃AlC₂ structure. The multiple-layered MXene were exfoliated into mono- or few-layered ones by using ultrasound assisted approach. XRD results indicate that the (002) crystal plane are left-shifted due to the surface termination and larger interlayer spaces of the samples. Electrochemical tests of the samples indicate the sample of Ti₃C₂T_x MXene composited with 0.5 g GO exhibits a capacity of 758 F/g at the scan rate of 10 mV/S, with the increasing of scan rate, the capacity retention rate is 58.83%, which is regarded as the optimum electrode.

It is discussed how the silver selenide concentration in glasses of the chalcogenide system (1 ‒ x)(0.27Sb₂Se₃–0.73GeSe₂)–xAg₂Se affects their plasticity, the relationship between microhardness and the glass transition temperature, and the binding energy of metal atoms in these glasses. Attention is focused on the many-fold increase in plasticity with an increase in the silver selenide content in chalcogenide glasses. These effects are associated with the formation of the metallophilic silver–silver interactions. The results of impedance measurements supplement the studies because the metallophilic interactions in chalcogenide glass can exert a strong effect on the glass transition temperature and many other important properties including the mechanism of electronic and ionic conduction.

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 electrochemical energy converters are described which, depending on the type, can be used both for generating electric energy and its accumulation in the form of chemical energy of active substances. An alternative scheme of the guaranteed supply of electricity and heat is considered for a region remote from the centralized energy supply but with a high potential of wind energy generation and hydrogen energy storage without using any imported or local fuel. The scheme includes a wind energy complex, i.e., a farm of wind turbines localized in sites with the high wind potential, which guarantees the electricity supply even during low wind periods. All surplus electricity is consumed in the thermoelectric heating of water in storage tanks and the hydrogen production by water electrolysis. Hydrogen is either stored or supplied to the fuel cell plant (used in windless periods or as an alternative power source) and to the hydrogen condensing boiler in heat-deficiency periods. The annual hydrogen energy balance, the necessary number of wind turbines, the parameters of the equipment scheme are calculated, and the capacity factors of the installed equipment are estimated for a real autonomous region (Novikovo village, Sakhalin island). The main prerequisites for the implementation of the alternative scheme of electricity and heat supply that uses no imported fuel but operates on wind power and electrochemically converted energy are shown.

Literature on electrochemical sensors highlights its expanding role in biomedical applications, supported by advancements in nanotechnology. This paper briefly explores the development and need for nanomaterials-based sensors with advanced technologies emphasizing sensitivity and selectivity and the critical role of electrochemical sensors in medicine. The devices that convert chemical reactions into measurable electrical signals have evolved significantly since its inception in the 18th century. Understanding advancements in nanotechnology, these sensors now play a crucial role in healthcare, enabling continuous monitoring, non-invasive diagnostics, and precise detection of various biological analytes. Numerous advancements, including fabrication techniques such as 3D printing, artificial intelligence and the internet of things, MXene, wearable sensors, and other analytical methods to enhance the performance and functionalities of electrochemical sensors, such as cancer detection, glucose monitoring, wearable health devices, etc. Based on the Google Scholar search, this review provides insights into the different nuances of electrochemical sensors developed since 2014.

The charging/discharging cyclic process in a hydrogen–bromine battery is studied. Porous titanium felt with IrO₂–TiO₂-mixed-oxide coating in contact with aqueous HBr/Br₂ solution is used as positive electrode (the cathode). A hydrogen gas-diffusion electrode with Pt–C catalytic layer served as negative electrode. The hydrogen ion is transferred between the electrodes through a GP-IEM 103 perfluorinated sulfocation-exchange membrane. The morphology, phase, and chemical composition of the cathode material are characterized using scanning electron microscopy with X-ray spectral microanalysis, Raman spectroscopy, and X-ray photoelectron spectroscopy. The condition for switching between the charging and discharging stages within each cycle (the voltage upper limit) is so chosen as to minimize the amount of bromide and polybromide anions relative to the molecular bromine formed at the end of the charging stage (oxidation of Br^–), instead of the traditionally used approach which includes only partial conversion of bromide to bromine, in order to increase the stability of the latter in the form of polybromide complexes. Charge–diacharge tests of the hydrogen–bromine battery are carried out in the galvanostatic mode at three current densities: 25, 50, and 75 mA/cm². Comparison of the charge and average voltage values in the course of the electrical energy generation (the discharge stage) and storage (the charge stage) shows that the highest efficiency of the cycle is achieved at the current density of 50 mA/cm². This value of the charging/discharging current density also corresponds to the maximal utilization of the electrolyte redox-capacity. The stability of the mixed-oxide cathode material used in contact with bromine compounds in acidic environment is found to exceed significantly that of the carbon paper. The principal reason of the decrease of the battery capacity from cycle to cycle is the molecular bromine absorption by elements of the system contacting the catholyte: components of the membrane–electrode assembly, pipelines, and elements of the pump that ensures the circulation.

The approach taken here is to build on the success of the Dissipation Theorem used to elucidate steady turbulent shear flows and apply it to homogeneous isotropic turbulence where the various physical mechanisms can be treated simultaneously by the development of a predictive method. For some time, it has been assumed that small eddies dissipate faster than large eddies and that energy is transferred from larger to smaller eddies to facilitate the overall process. In 1895, Osborne Reynolds [1] described in detail how velocity fluctuations generate turbulent dissipation and stress which are significantly larger than those due to local averaged velocity and pressure gradients. Here it is shown how the decay process can be explained by the turbulent-dissipation mechanism, with little or no inter-eddy transfer. In a homogeneous system, momentum transfer is not important, and a mechanical-energy balance is used instead. With no energy source, both volumetric dissipation and mechanical energy decrease with time. Apparent energy transfer among eddies of different size can be due to diffusion of spectral energy in wave-number space or due to elongation of eddies or due to eddies breaking into smaller eddies. The assumed initial energy spectrum continues to be reflected in the energy profile for a substantial time. This indicates that, in experimental systems, the total initial energy is concentrated near a wave number corresponding to the mesh spacing of the grid. The total mechanical energy is inversely proportional to time except for very early times and very late times. Experimental data of Comte-Bellot and Corrsin [2] are shown for comparison. The use of modified variables to eliminate the density and viscosity allows results to be applied to any Newtonian fluid and clarifies thinking about dimensional issues.

The binding interactions of (E)-1-((2,4-dichlorophenylimino)methyl)naphthalen-2-ol (DCPIMN) and (E)-1-((2-chloro-4-nitrophenylimino)methyl)naphthalen-2-ol (CNPIMN) with some biomolecules, namely, calf thymus DNA (ct-DNA) and serum albumins (HSA and BSA) were investigated by square-wave voltammetry (SWV) at physiological pH of 7.40. Also, the absorption, distribution, metabolism and excretion (ADME) profiles of DCPIMN and CNPIMN were reported. DCPIMN had an irreversible voltammetric peak at −1.352 V on the mercury electrode at pH 7.40. However, in physiological pH, electrochemical experiments revealed that CNPIMN showed two irreversible cathodic peaks owing to reductions of nitro and azomethine moieties, respectively. The variations in the current and potential values of reduction signals of DCPIMN and CNPIMN with adding of different concentrations of these biomolecules (BMs) were followed. The voltammetric experiments showed that although DCPIMN interacted with these BMs, CNPIMN only interacted with HSA. The binding constants (K) of these 1 : 1 interactions were calculated from electrochemical data. These K values showed that the binding strength of BSA to DCPIMN is stronger than those of HSA and ct-DNA compounds. Moreover, CNPIMN binds more strongly to HSA than DCPIMN. On the other hand, the molecular docking studies of DCPIMN and CNPIMN were carried out to evaluate their theoretical binding affinities. The binding affinity (BA) of BSA (–8.9 kcal/mol) with DCPIMN is higher than those of A-DNA, B-DNA and HSA. In addition, the BA value of HSA with CNPIMN is also greater than that of its interaction with DCPIMN. From the molecular docking results, it was found that there was a hydrogen bond between −NO₂ group of CNPIMN and ARG117 residue of HSA. Finally, pharmacokinetic properties of these Schiff bases exhibited that DCPIMN has the capability of blood-brain barrier (BBB) penetration; however, CNPIMN does not have this feature.

The interactions of clofazimime (CLF) with human serum albumin (HSA), bovine serum albumin (BSA) and calf thymus DNA (ct-DNA) were studied by square-wave voltammetry (SWV) at physiological pH. The cyclic voltammogram of CLF gave three reversible redox peak couples in the studied medium. SWV data showed that the cathodic current of CLF decreased by adding of HSA, BSA and ct-DNA owing to the molecular binding interactions. For these binding processes, thermodynamic quantities (ΔG°, ΔH° and ΔS°) and binding constants (K) were obtained and calculated from voltammetry data in the temperature range 295–310 K. Also, the molecular docking studies were carried out to obtain theoretical information about the interactions of CLF with A-DNA, B-DNA and serum albumins. The results of docking applications showed that CLF had the highest binding affinity (BA) for BSA.