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.

Developed rapid chemical vapor deposition lasting only 3 min allowed to produce smooth layered carbon nitride polycrystalline thin films as thick as 830-1547 nm at 550-625 degrees C in air with crystallites in the layers oriented parallel to the substrate (glass or silicon) surface. They are distinguished by high transparency in the visible range and the thickness uniformity. It made possible an adequate optical transmission and absorption spectra measurements at room temperature and their correct processing with the Swanepoel's envelope method to determine optical properties of the films and compare them with characteristics of carbon nitride materials obtained by conventional chemical vapor deposition or thermal polymerization. The application of the Swanepoel's method allowed to determine actual thickness of the films and then the refraction index of the material to be 2.50-3.25 and the extinction coefficient to be 0.1-0.4 as functions of the deposition temperature. The average photoluminescence lifetime of the deposited material is found to be 2.3-2.6 ns for high energy carrier recombination processes being the shortest in the sample fabricated at 550 degrees C and correlating with crystallinity of the film. Optimal temperature for rapid chemical vapor deposition of carbon nitride thin films is concluded to be in the range of 550-575 degrees C providing its best properties promising for electronic and optoelectronic applications.

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.

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.

Rapid chemical vapor deposition of continuous thin films of graphitic carbon nitride (g-CN) material with stoichiometry close to its ideal g-C3N4 form on silicon and glass substrates is demonstrated. It allows fabrication of 200-1200 nm g-CN films within 3-5 min at 500-620 degrees C instead of earlier reported few hours. SEM, XRD and EDX analysis of the films revealed their grain-layered structure and high crystallinity. The film thickness and crystallinity were found to have maximum at synthesis temperature of 575-600 degrees C. Energy band gap of the material changes with the deposition temperature too and reaches its maximum of 2.98 eV at 600 degrees C. Depen-dence of the film properties on the deposition temperature evidences competition between the rates of synthesis and evaporation of the synthesized material. The developed approach is energy budget saving and could be scaled up using conventional rapid thermal processing equipment opening a way to practical g-CN based elec-tronics and optoelectronics.

Sol-gel technology has attracted attention in the fabrication of diverse luminescent materials and thin film structures, with forms that range from powders to microcavities. The optical properties of sol-gel-derived structures depend on the sol composition, deposition, and heat treatment conditions, as well as on the film thicknesses and other factors. Investigations on the upconversion luminescence of lanthanides in film structures and materials are also ongoing. In this study, we synthesized three different types of materials and film structures using the same sol, which corresponded to a Ba0.76Er0.04Yb0.20TiO3 xerogel, as follows: (a) the target form, which used the explosive compaction method for sol-gel-derived powder; (b) single-layer spin-on xerogel films annealed at 450 and 800 °C; and (c) microcavities with an undoped SiO2/BaTiO3 Bragg reflector surrounding a Ba0.76Er0.04Yb0.20TiO3 active layer. The BaTiO3:(Er,Yb)/SiO2 microcavity exhibited an enhancement of the upconversion luminescence when compared to the BaTiO3:(Er,Yb) double-layer film fabricated directly on a crystalline silicon substrate. The reflection spectra of the BaTiO3:(Er, Yb)/SiO2 microcavity annealed at 800 °C demonstrated a deviation of the maxima of the reflection within 15% for temperature measurements ranging from 26 to 120 °C. From the analyses of the transmission and reflection spectra, the optical band gap for the indirect optical transition in the single layer of the BaTiO3:(Er,Yb) spin-on film annealed at 450 °C was estimated to be 3.82 eV, while that for the film annealed at 800 °C was approximately 3.87 eV. The optical properties, upconversion luminescence, and potential applications of the BaTiO3:(Er,Yb) sol-gel-derived materials and structures are discussed in this paper.

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.

Graphitic carbon nitride (g-C3N4 ) was synthesized by pyrolysis of thiocarbamide and a subsequent polymerization of its products at 500 °С. After grinding the synthesized material, aqueous suspensions with the concentrations of the particles of 100–300 μg/ml were prepared from it. The antibacterial activity of the material under irradiation with the LED’s visible light for 60–120 min was confirmed for Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa.

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.

Indium electrodeposition in-between silicon nanowire arrays fabricated by silver-assisted chemical etching of lightly-doped (100)-oriented silicon wafers is evaluated. It is concluded based on SEM and EDX analysis of indium’s distribution that, by utilizing pulsed-mode electrodeposition and maintaining a sufficiently low duty cycle value, indium particles can be formed exclusively at the very bottom of each consecutive pore on the residual silver particles left over from metal-assisted etching. This result differs significantly from irregular pore filling along with surface and subsurface deposition observed in the cases of continuous galvanostatic deposition regimes at prolonged durations or in the absence of residual silver particles. Bottommost fusible metal deposit localization, which is unattainable on porous silicon fabricated by electrochemical anodization, is presumed to be optimal for the growth of germanium crystallites inside the pores via the electrochemical liquid-liquid-solid approach and subsequent silicon-germanium alloy formation through thermal annealing.

Carrier separation, charge transport, and visible light absorption are the main factors affecting the solar water splitting performance of a semiconductor photoanode. In this work, ZnIn2S4 (ZIS) nanosheet arrays (NSAs) were prepared by a hydrothermal route on a transparent fluorine-doped tin oxide (FTO) substrate, which was followed by a modification with an amorphous FeOOH thin layer. The surface morphology of ZIS NSAs was shown not to change regardless of whether Au was used as the seeding layer. Besides, the effect of the FeSO4 solution concentration on the morphology, optical absorption, and photoelectrochemical (PEC) performance was investigated. The PEC measurements showed that at the 1.23 V bias relative to RHE (VRHE), the FeOOH/ZIS/Au optical photoanodes exhibited a 4.5 and 1.9 times higher photocurrent density than the ZIS/FTO and ZIS/Au/FTO electrodes, respectively. For the 0.05Fe/ZIS/Au/FTO samples, the 0.91 mA cm−2 initial photocurrent density was achieved at VRHE of 1.23 V. The FeOOH/Au/ZIS photoanodes also displayed a maximum H2 yield amount of 26.2 µmol cm−2 h−1. It was also observed that the enhanced PEC performance may be resulted from the synergistic effect of the FeOOH top decoration and Au under layer. Specifically, FeOOH facilitated the hole injection into the electrolyte, while Au NPs provided a number of sinks for the electron transport to the FTO substrates.

Owing to the distinctive and designable properties of high-entropy alloys (HEAs), many researchers have been engrossed in studying them. The CrFeNiNbx (x is the molar ratio; x = 0.4, 0.5, 0.6, 0.7, 0.8) alloys were prepared using vacuum arc melting furnace equipment to study the impact of Nb content on microstructure, processing performance, and corrosion resistance. Laves primary phase and eutectic structure phase were obtained. And the area of the Laves primary structure, which was rich in Nb, was amplified when the alloy's percentage of Nb was supplemented. The Nb4 alloy (x = 0.4) exhibited a range of satisfactory mechanical properties, including a hardness of 422.3 HV, a compressive stress of 2355 MPa, and a compressive strain of 26.33%. Cracks formed around the Laves phase during electrochemical corrosion experimentation, and the alloy passivation film's breakdown potential was approximately 1.0 V.

The development of a high-efficiency photocatalyst having favorable charge transfer has become an important scientific approach for solar-to-fuel conversion. In this study, the one-dimensional (1D)/2D CeO 2 /ZnIn 2 S 4 (ZIS) photocatalyst having a Z-scheme heterojunction has been successfully fabricated using the in situ growth of ZIS nanosheets on the CeO 2 nanorod surfaces. The optimal H 2 production rate of 3.29 mmol g −1 h −1 was achieved with the 15% CeO 2 /ZIS sample under visible light without any cocatalyst; furthermore, this value was 2.7 and 92.6 times higher than those of pristine ZIS and CeO 2 , respectively. The remarkable photocatalytic activity can be attributed to the efficient separation of photogenerated carriers as well as the formation of the Z-scheme heterojunction, which maintained the strong reduction of electrons in ZIS for H 2 production. The presence of an internal electric field between CeO 2 and ZIS has been demonstrated by both density functional theory calculations and Kelvin probe force microscopy. The Z-scheme transfer of photogenerated carriers in the CeO 2 /ZIS heterojunction has been confirmed by electron paramagnetic resonance spectroscopy and in situ irradiated X-ray photoelectron spectroscopy. This study presents certain insights into the development of efficient Z-scheme photocatalysts for H 2 evolution from solar water splitting.