Low-temperature operation remains a major challenge because sluggish Li+ transport and aggravated polarization severely compromise energy delivery and cyclability. Here we develop a wide-temperature tri-salt electrolyte comprising LiBF4, LiFSI and LiDFOB in a PC/DME/iBA solvent matrix. With an optimized formulation (0.75 M LiBF4, 0.2 M LiFSI, 0.05 M LiDFOB, PC : DME : iBA = 25:65:10, v/v/v, T-electrolyte), Li||LiCoO2 batteries deliver high reversibility, strong rate capability and durable cycling from − 20 to 40 °C. Remarkably, at −20 °C, the optimized electrolyte sustains 143.5 mAh g− 1 at 0.2 C and preserves 129.7 mAh g− 1 after 500 cycles, corresponding to 85.5

Low-temperature operation of lithium-ion batteries (LIBs) is severely limited by sluggish Li+ transport, aggravated interfacial polarization, and structural degradation of layered oxide cathodes. Herein, a multifunctional Li2O-B2O3-Li2SO4 composite coating, denoted as LBLS, was constructed on LiNi0.6Co0.2Mn0.2O2 (NCM622) through a simple wet-mixing/calcination strategy. Structural and surface characterizations confirm that the LBLS-derived layer is successfully introduced onto NCM622 while the layered α-NaFeO2 framework is well preserved. Benefiting from the regulated surface chemistry and improved interfacial kinetics, NCM622@LBLS exhibits significantly enhanced electrochemical performance, especially under subzero conditions. At −20 °C, the charge-transfer resistance decreases from 160 Ω for pristine NCM622 to 110 Ω after LBLS modification. Moreover, after 500 cycles at −20 °C, NCM622@LBLS maintains 101.57 mAh g−1 with a capacity retention of 80.60%, which compares favorably with representative coated NCM622 cathodes evaluated under comparable subzero conditions. In situ XRD reveals suppressed lattice breathing, while ex situ EIS, DRT and GITT confirm reduced interfacial polarization and faster Li+ diffusion. Depth-profiling XPS further demonstrates that LBLS promotes an inorganic-reinforced CEI containing Li–O, B–O/B–F, and SOx-containing species, thereby stabilizing the cathode/electrolyte interface during low-temperature cycling.

The nickel–cobalt–manganese ternary cathodes suffer from severe interfacial and structural instability at low temperatures, hindering their application in high-energy–density lithium-ion batteries. In this work, a 5-nm uniform lithium boron oxide (LBO) coating on LiNi0.6Co0.2Mn0.2O2 (denoted as NCM) was fabricated via a wet-chemical method. At −20 °C and 0.2 C, the LBO-coated NCM retains 84.84

The heteroatom doping is considered a promising strategy for enhancing the performance of the MnO2-based electrode materials for zinc-ion battery (ZIB). However, quickly discovering the high-performance doped-MnO2 remains significant challenge to simultaneously give consideration to both the various metal types, doping concentration, and the essential screening mechanism. Herein, a novel research paradigm is developed by combining machine learning predictions with systematic experiments and theoretical calculations for solving this issue. The results simulated by machine learning from the two-dimensional perspective reveal that only when Co species are introduced into b-MnO2 can zinc ions (Zn2+) maintain the smaller binding energy gradient distribution and larger activation area ratio among the constructed various doping system database, further achieving qualitative "structure-activity" descriptor. Moreover, the density functional theory (DFT) calculations systematically unveil optimal adsorption energy/Gibbs free energy, higher negative integral crystal orbital Hamilton population (-ICOHP) (0.0125 Ha), and lower Zn2+ diffusion barrier (0.978 eV) for moderate Co-doped b-MnO2 with oxygen vacancy (Co(M)-b-MnO2-x, where (M) denotes moderate Co-doping concentration) compared with the other samples, which can preserve the Zn2+ adsorption/desorption equilibrium and the structure integration, and accelerate the reaction kinetics. Benefiting from these advantages, the obtained ZIB using the optimized cathode can present the large specific capacity of 655.7 mAh & centerdot;g-1 at 0.5 A & centerdot;g-1 and high rate capability (209.8 mAh & centerdot;g-1 at 20 A & centerdot;g-1), which is far higher than those of the other compound cathode materials. This study offers new insights for the design and optimization of doped-b-MnO2 cathodes in ZIBs, and the obtained universal theoretical guidance is also suitable for constructing other high-performance layered electrode materials.

Silicon-germanium alloy films were formed by electrochemical deposition of germanium into porous silicon matrices with thicknesses varying from 1.5 to 10 mu m followed by subsequent rapid thermal processing at 950 degrees C in an inert atmosphere. Study of the fabricated structures using SEM and Raman spectroscopy, as well as measurements of their electrical conductivity and thermoelectric properties revealed that the highest Seebeck coefficient (-505 mu V/K at 450 K) and Power Factor (1950 mu W/(m & sdot;K2) at 400 K) values were obtained when a 5 mu m-thick porous silicon was used as a structural matrix. Under such conditions, an optimal balance between electrical conductivity, structural disorder and electrical insulation from the substrate is achieved due to the presence of a residual porous underlayer, making it possible to maximize the film's thermoelectric performance. The obtained silicon-germanium alloy films are deemed suitable for the fabrication of both discrete and integrated thermoelectric devices based on monocrystalline silicon substrates.

Thermoelectric materials based on cobalt-containing SiGe alloy films were fabricated using monocrystalline silicon wafers with thin porous silicon layers electrochemically decorated with cobalt nanoparticles, filled germanium and subsequently subjected to rapid thermal processing. SEM, XRD, Raman spectroscopy and measurements of electrical conductivity and thermoelectric parameters revealed that an intermediate silicidization step involving thermal processing at 850 degrees C after cobalt deposition is crucial to maximize the resulting alloy's thermoelectric capabilities. The obtained silicidized SiGe:Co samples demonstrate a Seebeck coefficient of -450 mu V/K and an estimated figure-of-merit ZT value of up to 0.72 at 450 K due to the presence of crystalline cobalt silicides in the film. These results enable a new approach to the fabrication of thin film thermoelectric materials based on SiGe alloys.

Film structures based on Si1–xGex (0 < x < 1) solid solutions are currently obtained by chemical-vapor-deposition methods. For device application of the obtained structures, it is necessary to know the electrical properties of the material synthesized under different conditions. In this work, we carry out galvanomagnetic studies of the electrical conductivity in porous and solid Si1–xGex films, as well as the concentration and mobility of the majority charge carriers in them at a temperature of 30–300 K. It is shown that, as in pure silicon and germanium of comparable porosity, the electrical conductivity in the studied samples can be considered as in a medium with voids. It is established that the type of majority charge carriers in the alloy is determined by the type of silicon substrate used. This is practically important for creating both arms of a thermoelectric converter, which makes the method for producing Si1–xGex(0 < x < 1) alloy promising for device applications, in particular in thermoelectric converters and lithium-ion batteries.

This work experimentally and theoretically analyzes the dynamics of the process of ion emission from a capillary emitter filled with an ionic liquid as a working fluid. Such emitters can be used in the energy system of low-mass satellites as a source of jet propulsion. The dependence of the thrust of a micromotor on the electrical power supplied to it was experimentally studied, which made it possible to determine the most efficient operating modes of the microthruster. This is of interest from the point of view of increasing the energy efficiency of the latter in conditions of limited power availability of low-mass satellites. It was found that the characteristic “electric field voltage – emitter thrust” is non-monotonic with a pronounced maximum, which imposes restrictions on the magnitude of the electric field in the emitter. To explain the limit of emission intensity, a diffusion-convective model of ion movement inside the capillary was constructed. The main idea of the proposed model is the assumption that the intensity of ion emission is determined by their concentration at the outlet of the capillary, and the velocity of the emitted ions is higher than the velocity of flow of the ionic liquid in the capillary as a continuous medium. Moreover, the acceleration of ions at the outlet of the emitter increases nonlinearly with increasing external forces. The decrease in the concentration of ions as they are emitted must be compensated by their diffusion inside the capillary and convective flows, the velocity of which is limited. The constructed system of equations is analyzed numerically. For the system of Navier – Stokes equations, the projection method proposed by Chorin is applied. Based on the known velocity field, density, and concentration distribution, a time step is taken for the equations of motion. Then, taking into account the found velocity, a time step is taken for the convective diffusion equations and the density field is recalculated. The created code made it possible to confirm the possibility of the existence of a maximum mass flow rate of ions, i.e., micromotor thrust, which is in qualitative agreement with the experimental data. The main factor on which the magnitude of the maximum and its position depend is the degree of nonlinearity of the coefficient responsible for the acceleration of ions at the outlet of the capillary.

By combining sol-gel and hydrothermal deposition methods on glass substrates, thin-film coatings of zinc oxide doped with nickel and aluminum were obtained. Studies of the structure and composition of the films using scanning electron microscopy, energy-dispersive X-ray and Raman spectroscopy have shown that they consist of close-packed zinc oxide crystallites doped with impurity atoms of nickel and aluminum. Resistive type photodetectors were manufactured based on the films obtained. It has been shown that when irradiated with ultraviolet light with a wavelength less than 400 nm, the resistivity of the structure decreases from 190–210 to 7.5–8.0 Ohm⋅cm. The achieved response time for the rise of the light pulse is 48 s, while the decay time is ≈700 s.

The recent results of the investigations performed in the research units of the Department of Micro- and Nanoelectronics of Belarusian State University of Informatics and Radioelectronics in the field of the development of perspective optical and electronic intra-chip and inter-chip interconnections of silicon integrated circuits are summarized. Examples of the use of nanostructured materials for the proposed light sources and detectors (Si) as well as light guides (Al2O3/TiO2) integrated with monocrystalline silicon are presented. The strategy of an application of inter-chip interposers for optical and electronic connections in bulk (2.5D and 3D) packages of integrated circuits was promoted and tested. Novel materials and structures promising for light sources, optically transparent electrical conductors and protectors against microwave electromagnetic radiation are demonstrated.

A variety of micro‐ and nanocomposite materials based on electrochemically‐acquired porous silicon are produced and evaluated in terms of their applicability to display technology. It is shown that porous silicon provides a versatile and well‐adjustable template for filling with other materials, which can outright change its electrophysical parameters. While, in terms of display applications, porous silicon layers are mostly prominent for their photohiminescence not akin to monocrystalline silicon, this property can be additionally enhanced by employing a variety of electrochemical techniques to form metal deposits of certain shapes.

Morphology and crystalline structure of silicon-germanium alloys formed by rapid thermal processing of germanium-filled porous silicon layers are evaluated. Two types of porous silicon are employed as matrices for electrochemical pore filling using GeO2 aqueous solutions and subsequently compared, the first one formed by electrochemical anodization and the second by silver-assisted chemical etching of monocrystalline silicon. The resulting alloys' structure and composition are investigated using scanning electron microscopy, energy -dispersive X-ray analysis, Raman spectroscopy and X-ray powder diffraction. It is shown that by varying the porosity of the initial matrix (by adjusting anodization current density for anodic porous silicon or changing silver deposition time for structures produced by metal-assisted etching) in the range from 55 to 75%, Si1-xGex alloys with germanium fractions of x = 0.31 to x = 0.83 can be formed, as indicated by Raman spectroscopy. It is concluded that composition-adjustable layers of silicon-germanium can be successfully formed on either type of porous silicon layer. While an increase in porosity generally leads to a decrease in silicon fractions in the alloy, the steepness of this effect varies heavily depending on the type of porous matrix used and should be considered independently for anodic porous silicon and silicon nanowires.

Using scanning electron microscopy, the structures of the surface and internal regions of porous silicon obtained by anodizing heavily doped plates of single-crystal silicon with electron conductivity in a hydrofluoric acid solution at different current densities were studied. It is found that the porous silicon surface has dark gray and light gray pores, which differ in size and surface distribution density. Dark gray pores possess larger sizes, and their density is about 5–10 times less than that of light gray pores. Based on the cross-section imagery, it is shown that light gray pores correspond to underdeveloped channels of small depth, while dark gray pores are the entrance points of deep bottle-shaped channels passing from the surface into the depth of the silicon wafer. The equivalent diameters of light gray pores on the surface of porous silicon are 12–15 nm and are practically independent of the anodic current density. At the same time, the equivalent diameters of dark gray pores and average distances between their centers increase linearly from 15 to 35 nm on the surface and from 35 to 120 nm in the volume of porous silicon when the current density is increased from 30 to 90 mA/cm2. The average thickness of silicon skeleton elements is about 3 nm on the surface and increases to 5–6 nm in the volume. By setting the density of the anode current, it is possible to obtain layers of porous silicon with different structural parameters. The obtained research results have practical significance for the formation of composite materials based on porous silicon, which can be used as a porous matrix for the deposition of metals and semiconductors.

Morphology and crystalline structure of silicon-germanium alloys formed by rapid thermal processing of germanium-filled porous silicon layers are evaluated. Two types of porous matrices are used for electrochemical pore filling using GeO2 aqueous solutions and subsequently compared, the first one formed by electrochemical anodization and the second by metal-assisted chemical etching of monocrystalline silicon. The resulting alloys’ structure and composition are investigated using scanning electron-microscopy, Raman spectroscopy and X-ray powder diffraction. It is concluded that layers of silicon-germanium can be successfully formed on either type of porous layer, exhibiting some minor distinctions in uniformity but no major difference between the resulting alloys’ composition.

As a transition metal phosphide, copper phosphide (Cu3P) undergoes high volume expansion and reduced electrical conductivity during cycling, causing kinetic issues and rapid capacity fading. The well-dispersed and sheet-like structure of individual nano-copper phosphide particles is crucial for alleviating volume expansion and enhancing kinetic behavior, which however have been rarely concerned. In this work, we report a novel heterostructure with nano-copper phosphide particles immobilized on phosphorus doped carbon nanosheet (Cu3P@PCNSs) by using Cu-BDC as the precursor. When the synthesis temperature is 600 ?, the Cu3P@PCNSs-600 exhibits a remarkable rate capability (383.4 mA h g(-1) at 2 A g(-1)) and outstanding long-term durability (436.4 mA h g(-1) at 1000 mA g(-1 )after 1000 cycles) for lithium storage. The monodisperse structure of Cu3P nanoparticles embedded in phosphorus doped carbon could reduce the volume change of Cu3P nanoparticles. Moreover, the electron density, adsorption energy, diffusion barrier and other properties of Cu3P and carbon matrix heterostructures were calculated in accordance with density functional theory (DFT). As dndicated by the calculation, the strong interaction between the heterostructures had an effect on the adsorption capacity of Li, and the experimental results were confirmed to be correct. This novel Cu3P@PCNSs electrode can be used as an effective strategy for applying other transition metal electrode materials in lithium-ion batteries.

A method of germanium electrodeposition from a GeO2-based aqueous solution into the pore channels of anodic mesoporous silicon formed on n-type highly-doped (100) silicon wafers is described. The effect of deposition time, pore channel shape and preconditioning of porous silicon layers in hydrofluoric acid is evaluated. Recommendations are given in regards to the optimal parameter combinations to ensure uniform pore channel filling with germanium. The possibility of producing silicon-germanium alloys by subsequent rapid heat treatment of the germanium-filled porous silicon layers is established.

The optical properties of ZnO films doped with the Ni and Co transition metals that were hydrothermally deposited on a silicon substrate are discussed. The SEM, EDX, XRD and Raman spectroscopy studies showed that the films deposited have a compact crystalline structure and can be considered as nanostructured polycrystalline ZnO films doped with Ni and Co and designated as ZnO:Ni and ZnO:Co, respectively. Under optical and electronic excitation, the films demonstrated both near-band-edge ultraviolet and visible range luminescence due to crystal lattice defects. The highest intensity of the ultraviolet luminescence with a fast decay was achieved for the ZnO:Ni and ZnO:Co samples deposited in the 0.05 M solutions of Ni or Co nitrate salts. Wide luminescence spectra make the films obtained promising as luminophore or scintillating coatings for the beta-particles detection including structures integrated with silicon circuits, for example, solid state silicon-based radiation counters.

Films of cobalt oxide and nickel oxide on monocrystalline silicon substrates were obtained by electrochemical deposition from aqueous electrolyte solutions. Their structure and composition were studied by Raman microscopy and scanning electron microscopy. The results of the study by Raman spectroscopy showed that the obtained films are polycrystalline structures of cobalt (II, III) oxide and nickel (II) oxide, the crystalline perfection of which increases with an increase in the electrolyte temperature. It was found by scanning electron microscopy that nickel oxide films have a smoother surface, while cobalt oxide has a more developed structure consisting of lamellar crystals. The specific electrochemical capacity of cobalt oxide and nickel oxide films obtained under optimal conditions, measured by voltammetry, was 14.67 and 1634.08 F/g, respectively. The high specific electrochemical capacity of a nickel oxide film can be used to create efficient electrochemical devices and energy storage devices.

In this work, we propose a new, previously unpresented in the literature, approach to the formation of Si1-xGex films. This approach includes electrochemical processes of the formation of porous silicon, electrochemical deposition of low-melting metals and Ge. Post-heat treatment is made possible to synthesize film structures based on Si1-xGex solid solutions. Using this approach an alloy of the composition Si0.4Ge0.6 has been obtained at a lower formation temperature than predicted by the phase diagram for the Si-Ge system.