Search Results (363)

One of the advantages of the EPR spectroscopy method in assessing structural defects caused by irradiation is the fact that using this method it is possible to determine not only the concentration dependences of the defect structure but to also establish their type, which is not possible with methods such as X-ray diffraction or scanning electron microscopy. Based on the data obtained, the role of variation in the ratio of components in Li₄SiO₄–Li₂TiO₃ ceramics on the processes of softening under high-dose irradiation with protons simulating the accumulation of hydrogen in the damaged layer, as well as the concentration of structural defects in the form of oxygen vacancies and radiolysis products on the processes of high-temperature degradation of ceramics, was determined. It was found that the main changes in the defect structure during the prolonged thermal exposure of irradiated samples are associated with the accumulation of oxygen vacancies, the density of which was estimated by the change in the intensity of singlet lithium, characterizing the presence of E-centers. At the same time, it was found that the formation of interphase boundaries in the structure of Li₄SiO₄–Li₂TiO₃ ceramics leads to the inhibition of high-temperature degradation processes in the case of post-radiation thermal exposure for a long time. Also, during the conducted studies, the role of thermal effects on the structural damage accumulation rate in Li₄SiO₄–Li₂TiO₃ ceramics was determined in the case when irradiation is carried out at different temperatures. During the experiments, it was determined that the main contribution of thermal action in the process of proton irradiation at a fluence of 5 × 10¹⁷ proton/cm² is an increase in the concentration of radiolysis products, described by changes in the intensities of spectral maxima, characterized by the presence of defects such as ≡Si–O, SiO₄³⁻ and Ti³⁺ defects. Full article

The (1−x)Ba_0.96Ca_0.04TiO₃−xBi(Li_1/3Zr_2/3)O₃ (x = 0.03–0.15) ceramics were fabricated via the traditional solid reaction method. Characterization results revealed that each component exhibited a pure perovskite structure, and the average grain size significantly diminishes with increasing x. The (1−x)Ba_0.96Ca_0.04TiO₃−xBi(Li_1/3Zr_2/3)O₃ ceramics exhibited prominent relaxor ferroelectric behavior, whose characteristic narrow hysteresis loops effectively enhanced the energy storage performance of the material. Most importantly, the composition with x = 0.10 demonstrated exceptional energy storage properties at 150 kV/cm, achieving a high recoverable energy storage density (W_rec = 1.91 J/cm³) and excellent energy efficiency (η = 90.87%). Under the equivalent electric field, this composition also displayed a superior pulsed discharge performance, including a high current density (871 A/cm²), a high power density (67.3 MW/cm³), an ultrafast discharge time (t_0.9 = 109 ns), and a discharged energy density of 1.47 J/cm³. These results demonstrate that the (1−x)Ba_0.96Ca_0.04TiO₃−xBi(Li_1/3Zr_2/3)O₃ ceramic system establishes a promising design paradigm for the creation and refinement of next-generation dielectrics for pulse power applications. Full article

An altermagnet, characterized by its distinctive magnetic properties, may hold potential applications in diverse fields such as magnetic materials, spintronics, data storage, and quantum computing. As a prototypical altermagnet, RuO₂ exhibits spin polarization and demonstrates the advantageous characteristics of high electrical conductivity and low thermal conductivity. These exceptional properties endow it with considerable promise in the emerging field of thermal spintronics. We studied the electronic structure and thermoelectric properties of RuO₂; the constructed RuO₂/TiO₂/RuO₂ all-antiferromagnetic tunnel junction (AFMTJ) exhibited thermally induced magnetoresistance (TIMR), reaching a maximum TIMR of 1756% at a temperature gradient of 5 K. Compared with prior studies on RuO₂-based antiferromagnetic tunnel junctions, the novelty of this work lies in the thermally induced magnetoresistance based on its superior thermoelectric properties. In parallel structures, the spin-down current dominates the transmission spectrum, whereas in antiparallel structures, the spin-up current governs the transmission spectrum, underscoring the spin-polarized thermal transport. In addition, thermoelectric efficiency emphasizes the potential of RuO₂ to link antiferromagnetic robustness with ferromagnetic spin functionality. These findings promote the development of efficient spintronic devices and spin-based storage technology for waste heat recovery and emphasize the role of spin splitting in zero-magnetization systems. Full article

The rocks of the Burpala alkaline intrusion contain a wide range of rare minerals that concentrate rare earth elements (REEs), Nb, Th, Li, and other incompatible elements. One of the examples of the occurrence of such mineralization is albite–aegirine rocks located at the contact zone between the intrusion and the host terrigenous–sedimentary rock. In albite–aegirine rocks, cubic crystals of “metaloparite”, partially or completely substituted by bastnäsite-(Ce) and polymorphic TiO₂ phases (anatase and rutile) mainly represent the rare metal minerals. In albite–aegirine rocks, trace element minerals are predominantly represented by cubic crystals of “metaloparite”, which are partially or completely replaced by bastnäsite-(Ce) and polymorphic TiO₂ phases such as anatase and rutile. Additionally, Th-bearing zircon (up to 17.7 wt% ThO₂) and a variety of unidentified minerals containing REEs, Th, and Nb were detected. The obtained data indicate that bastnäsite-(Ce) is the result of the recrystallization of “metaloparite” accompanied by the formation of Th-bearing zircon and Nb-bearing rutile (up to 9.9 wt% Nb₂O₅) and the separation of various undiagnosed, unidentified LREE phases. Our studies show that remobilization of LREEs, HFSEs, and local enrichment of rocks in these elements occurred due to the effects of residual fluid enriched in fluorine and carbon dioxide. Full article

This study presents the development of a TiO₂ nanowire-based electrochemical sensor for the selective and sensitive detection of hydrogen peroxide (H₂O₂) under neutral pH conditions, with a particular focus on its application in analyzing plant stress. The sensor exhibited a linear detection range of 0–0.5 mM, a sensitivity of 0.0393 mA · mM⁻¹, and a detection limit of 2.8 μM in phosphate-buffered saline solution (PBS, pH 7.4). This work’s main novelty lies in the systematic investigation of the relationship between TiO₂ nanostructure morphology, which is controlled by hydrothermal synthesis parameters, and the resulting sensor performance. Interference studies confirmed excellent selectivity in the presence of common electroactive species found in plant samples, such as NaCl, KNO₃, glucose, citric acid, and ascorbic acid. Real sample analysis using barley plant extracts grown under salt stress and treated with Fe₃O₄ nanoparticles confirmed the sensor’s applicability in complex biological matrices, enabling accurate quantification of endogenously produced H₂O₂. Endogenous H₂O₂ concentrations were found to range from near-zero levels in control and Fe₃O₄-only treated plants, to elevated levels of up to 0.36 mM in salt-stressed samples. These levels decreased to 0.25 and 0.15 mM upon Fe₃O₄ nanoparticle treatment, indicating a dose-dependent mitigation of stress. This finding was supported by genome template stability (GTS) analysis, which revealed improved DNA integrity in Fe₃O₄-treated plants. This study takes an integrated approach, combining the development of a nanostructured sensor with physiological and molecular stress assessment. The urgent need for tools to detect stress at an early stage and manage oxidative stress in sustainable agriculture underscores its relevance. Full article

The development of high-performance and stable solid-state lithium batteries (SSBs) is critical for advancing next-generation energy storage technologies. This study investigates LATP (Li_1.3Al_0.3Ti_1.7(PO₄)₃) coatings to enhance the electrochemical performance and interface stability of NCMA83 (LiNi_0.83Co_0.06Mn_0.06Al_0.05O₂) cathodes. Compared to conventional combinations with LPSC (Li₆PS₅Cl) solid electrolytes, LATP coatings significantly reduce interfacial reactivity and improve cycling stability. Structural and morphological analyses reveal that LATP coatings maintain the crystallinity of NCMA83 while fine-tuning its lattice stress. Electrochemical testing demonstrates that LATP-modified samples (83L5) achieve superior capacity retention (65 mAh/g after 50 cycles) and reduced impedance (R_ct ~200 Ω), compared to unmodified samples (83L0). These results highlight LATP’s potential as a surface engineering solution to mitigate degradation effects, enhance ionic conductivity, and extend the lifespan of high-capacity SSBs. Full article

Nanostructured binary metal oxides have demonstrated the potential for increased electrochemical performance due to their structural stability, electronic conductivity, and various oxidation states. The Li₄Ti₅O₁₂ was successfully synthesized via a hydrothermal procedure at different reaction periods (12, 18, and 24 h), and its microstructural and supercapacitive characteristics were studied. The XRD and XPS studies confirm the formation of Li₄Ti₅O₁₂ in pure phase when synthesized at 24 h (LTO@24) of reaction time. FESEM and HRTEM images reveal nanoflake surface morphology. Both LTO@24 and V-LTO@24 nanoflakes exhibited impressive electrochemical performance, with specific capacitance values of 357 and 442 F g^−1, respectively, at 1 A g⁻¹. The V-LTO@24 showed remarkable supercapacitor properties, demonstrating excellent rate capability and cycleability that surpass those of pure LTO@24. Full article

In this study, we address the need for sustainable and scalable synthesis routes for hydrogen storage materials by developing a FeTi alloy in which vanadium (V) partially substitutes for titanium (Ti). The alloy was synthesized using mechanical alloying, compaction, and post-annealing, employing industrial-grade Fe and Ti powders and an alternative to pure vanadium, i.e., ferrovanadium (Fe–V). X-ray diffraction (XRD) analysis of the mechanically alloyed mixture revealed the partial formation of a Fe(V) solid solution, along with residual Ti. Subsequent compaction and annealing at 1000 °C led to the formation of the FeTi(V) phase, accompanied by two minor secondary phases, Fe₂Ti and Fe₂Ti₄O. A maximum phase yield of 90% for FeTi was achieved after 48 h of annealing. The novelty of this work lies in the demonstration of a sustainable and economical synthesis approach for V-substituted FeTi alloys using industrial-grade raw materials, offering a potential reduction in the carbon footprint compared with conventional melting techniques. Full article

The complex dielectric permittivity has been studied with the waves of millimeter wavelength for rare earth manganate and titanate and LiCoPO₄ and LiNi_0.5Co_0.5PO₄ orthophosphate composites. The measurements are carried out at frequencies of 26 to 38 GHz via measurements of transmission and reflection coefficients through a plate. A special method on how to extract the real and imaginary parts of dielectric permittivity is applied. Discussion is conducted on a nonmonotonic type of the frequency dependences for both real and imaginary parts of permittivity, and it has been shown that relaxation is non-Debye. The Cole–Cole, Havriliak–Negami, and Kohlrausch–Williams–Watts models cannot also explain the nonmonotonic frequency dependence of the real part of dielectric permittivity. Investigation of the structure and phase composition of nanocomposites has been carried out. Full article

Nanotechnology is an emerging field in science that exhibits significant promise in the synthesis of nanomaterials for diverse applications. Traditionally, these nanomaterials were manufactured using hazardous and labor-intensive physical and chemical processes. Nevertheless, in recent years, researchers have developed safer, more scalable, and environmentally friendly methods for green synthesis. The problem addressed in this study is the need for an environmentally friendly and efficient synthesis process for titanium dioxide nanoparticles (TiO₂ NPs) with enhanced properties. The aim of this work is to describe the synthesis of TiO₂ NPs with various plant extracts using a green approach and to evaluate the physicochemical characteristics and potential applications of the resulting nanoparticles. This study focuses on understanding how the integration of plant extracts influences the properties of TiO₂ NPs, particularly in terms of their structural, optical, and functional characteristics. The novelty lies in the use of plant extracts as bio-reductants and capping agents, which not only provides a safer and more sustainable synthesis method but also enhances the functional properties of TiO₂ NPs. This green synthesis approach reduces the use of harmful chemicals, making the process more environmentally friendly and economically viable, with potential applications in photocatalysis, antibacterial, and antioxidant activities. The TiO₂ NPs possess diverse functionalities, including photocatalysis, antibacterial properties, and antioxidant properties. The initial precursor, such as a metal salt, undergoes transformation into the desired nanoparticles through the actions of plants exactly. Bio-reduction and capping processes are carried out by secondary metabolites found in bacteria and plants. The results demonstrated that the plant extract-mediated TiO₂ NPs exhibited enhanced photocatalytic activity, superior antibacterial effects, and higher antioxidant potential compared to chemically synthesized TiO₂ NPs. This highlights the potential of green synthesis methods in producing nanomaterials with improved functional properties for a wide range of applications. Full article

The iron and steel industry, as a major energy consumer, was critically required to enhance operational efficiency and reduce CO₂ emissions. Conventional blast furnace processing of vanadium–titanium magnetite (VTM) in China had been associated with persistent challenges, including suboptimal TiO₂ recovery rates (<50%) and elevated carbon intensity (the optimal temperature range for TiO₂ recovery lies within 1400–1500 °C). Shaft furnace technology has emerged as a low-carbon alternative, offering accelerated reduction kinetics, operational flexibility, and reduced environmental impact. This study evaluated the low-carbon PLCsmelt process for VTM smelting through energy–mass balance modeling, comparing two gas-recycling configurations. The process integrates a pre-reduction shaft furnace and a melting furnace, where oxidized pellets are initially reduced to direct reduced iron (DRI) before being smelted into hot metal. In Route 1, CO₂ emissions of 472.59 Nm³/tHM were generated by pre-reduction gas (1600 Nm³/tHM, 64.73% CO, and 27.17% CO₂) and melting furnace top gas (93.98% CO). Route 2 incorporated hydrogen-rich gas through the blending of coke oven gas with recycled streams, achieving a 56.8% reduction in CO₂ emissions (204.20 Nm³/tHM) and altering the pre-reduction top gas composition to 24.88% CO and 40.30% H₂. Elevating the pre-reduction gas flow in Route 2 resulted in increased CO concentrations in the reducing gas (34.56% to 37.47%) and top gas (21.89% to 26.49%), while gas distribution rebalancing reduced melting furnace top gas flow from 261.03 to 221.93 Nm³/tHM. The results demonstrated that the PLCsmelt process significantly lowered carbon emissions without compromising metallurgical efficiency (CO₂ decreased about 74.48% compared with traditional blast furnace which was 800 Nm³/tHM), offering a viable pathway for sustainable VTM utilization. Full article

KSnI₃-based perovskite solar cells have attracted a lot of research interest due their unique electronic, optical, and thermal properties. In this study, we optimized the performance of various lead-free perovskite solar cell structures—specifically, FTO/Al–ZnO/KSnI₃/rGO/Se, FTO/LiTiO₂/KSnI₃/rGO/Se, FTO/ZnO/KSnI₃/rGO/Se, and FTO/SnO₂/KSnI₃/rGO/Se, using the SCAPS-1D simulation tool. The optimization focused on the thicknesses and dopant densities of the rGO, KSnI₃, Al–ZnO, LiTiO₂, ZnO, and SnO₂ layers, the thickness of the FTO electrode, as well as the defect density of KSnI₃. This yielded PCE values of 27.60%, 24.94%, 27.62%, and 30.21% for the FTO/Al–ZnO/KSnI₃/rGO/Se, FTO/LiTiO₂/KSnI₃/rGO/Se, FTO/ZnO/KSnI₃/rGO/Se, and FTO/SnO₂/KSnI₃/rGO/Se perovskite solar cell configurations, respectively. The FTO/SnO₂/KSnI₃/rGO/Se device is 7.43% more efficient than the FTO/SnO₂/3C-SiC/KSnI₃/NiO/C device, which is currently the highest performing KSnI₃-based perovskite solar cell in the literature. Thus, our FTO/SnO₂/KSnI₃/rGO/Se perovskite solar cell structure is now, by far, the most efficient PSC design. Its best performance is achieved under ideal conditions of a series resistance of 0.5 Ω cm², a shunt resistance of 10⁷ Ω cm², and a temperature of 371 K. Full article

Na₄Fe₃(PO₄)₂P₂O₇ (NFPP) is recognized as a prospective electrode for sodium-ion batteries (SIBs) because of its structure stability, economic viability and environmental friendliness. Nevertheless, its commercialization is constrained by low operating voltage and limited theoretical capacity, which result in a power density significantly inferior to that of LiFePO₄. To address these limitations, in this work, we first designed and synthesized a series of Mn-doped NFPP to enhance its operating voltage, inspired by the successful design of LiFe_1-xMn_xPO₄ cathodes. This approach was implemented to enhance the operating voltage of the material. Subsequently, the optimized Na₄Fe_1.2Mn_1.8(PO₄)₂P₂O₇ (1.8Mn-NFMPP) sample was selected for further Ti-doped modification to enhance its cycle durability and rate performance. The final Mn/Ti co-doped Na₄Fe_1.2Mn_1.7Ti_0.1(PO₄)₂P₂O₇ (0.1Ti-NFMTPP) material exhibited a high operating voltage of ~3.6 V (vs. Na⁺/Na) in a half cell, with an outstanding reversible capacity of 122.9 mAh g⁻¹ at 0.1 C and remained at 90.6% capacity retention after 100 cycles at 0.5 C. When assembled into a coin-type full cell employing a commercial hard carbon anode, the optimized cathode material exhibited an initial capacity of 101.7 mAh g⁻¹, retaining 86.9% capacity retention over 50 cycles at 0.1 C. These results illustrated that optimal Mn/Ti co-doping is an effective methodology to boost the electrochemical behavior of NFPP materials, achieving mitigation of the Jahn–Teller effect on the Mn³⁺ and Mn dissolution problem, thereby significantly improving structural stability and cycling performance. Full article

The in situ electrochemical behaviors of Ti-39Nb-6Zr alloy were investigated in 2.3 ppm Li⁺ and 1500 ppm B³⁺ solution at 300 °C and 14 MPa. The activation energy is 12.84 kJ/mol, and the oxidation of titanium is controlled by oxygen ions diffusion in the liquid phases. The morphology, phase structure, and composition of the oxide film after 700 h exposure time in 300 °C and 14 MPa solution were characterized. The oxide film mainly included anatase TiO₂ phases, ZrO₂, Nb₂O₅, and a slight B₂O₃. The morphology of the film is shown by many nanocrystalline grains and the thickness is about 5 μm. The passivation film on the alloy substrate transforms from a single-layer film structure to a double-layer film structure. The impedance of the passivation decreases with the increase in temperature, which is related to the enhanced ion conductivity of the passivation film at high temperatures. The impedance of the dense layer inside the passivation film is much greater than that of the loose layer outside, and the dense layer inside plays a crucial role in the corrosion resistance of the Ti-39Nb-6Zr alloy. During the insulation process, the impedance of the dense layer inside the passivation film first increases and then slowly decreases, and the corrosion resistance of the passivation film first increases and decreases. Full article

The development of a simple and reliable strategy to synthesize cathode materials is crucial for achieving the overall high performance of rechargeable lithium batteries, which has proved to be quite challenging. Herein, we report a simple sol–gel method for the synthesis of Li₂FeTiO₄ cathode materials. The reaction mechanism of Li₂FeTiO₄ crystals can be divided into five stages: including the breakage of the coordination bond; the thermal decomposition of citric acid; the thermal decomposition of metal salts and the reduction of trivalent iron and the formation of Li₂FeTiO₄ crystals. Finally, the optimum calcination temperature for the preparation of Li₂FeTiO₄ cathode materials was explored. The Li₂FeTiO₄ cathode material prepared at 700 °C provides a discharge-specific capacity of 121.3 mAh/g in the first cycle and capacity retention of 89.2%. Our results provide new insights into the application of Li₂FeTiO₄ cathode materials. Full article