Journal of Materials Science最新文献

In this paper, an electrospinning composite material for solar energy storage was prepared by combining 2-methyl-acrylic acid 6-[4-(4-methoxy-phenylazo)-phenoxy]-hexyl ester (MAHE) as molecular solar thermal (MOST) molecule and polyethylene glycol-2000 (PEG) as phase change material (PCM) using electrospinning technique for the first time. In the composite fibers, both kinds of energy storage molecules successfully carried out energy storage and release behavior, and the enthalpy value reached 11.623 J/g. MAHE molecule in the composite showed good fatigue resistance in the reversible charge and discharge process within 50 cycles. It is more noteworthy that the materials obtained by electrospinning have excellent leakage resistance. The experimental results show that electrospinning has a wide development potential in the preparation of solar energy storage materials.

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We report here, the microwave-assisted synthesis of the copolymer viz poly(aniline-co-indole) (PAI) nanocomposite, and subsequent incorporation of nitrogen-doped carbon dots on the polymer. The resulting polymer nanocomposite exhibited a large specific capacitance of 670.23 F g⁻¹ at a current density of 0.50 A g⁻¹ in conjunction with excellent cycling stability of 94% capacitance retention after 1000 cycles at 0.5 A g ⁻¹. In vitro cytotoxicity evaluations for the copolymer and the nanocomposite demonstrated remarkable biocompatibility. The excellent electrochemical performance combined with good biocompatibility makes it a potential alternative to traditional supercapacitors.

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Graphical abstract for the synthesis of polymer nanocomposite (PAI-1) for supercapacitor applications

Bis (8-hydroxyquinoline) copper (CuQ₂) is an important organometallic complex based on a central metal cation coordinated to quinolate ligands. However, CuQ₂ exhibits limitations such as low fluorescence intensity, short fluorescence lifetime, and low efficiency of visible light absorption. In this study, density functional theory (DFT) calculations were performed to investigate the frontier molecular orbitals of CuQ₂, revealing its potential for excellent luminescence properties. Subsequently, CuQ₂ was synthesized using physical vapor deposition (PVD), yielding micron-sized CuQ₂ particles. CuQ₂ micron particles were characterized using scanning electron microscopy (SEM), X-ray diffraction spectroscopy (XRD), fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), ultraviolet visible spectroscopy (UV–Vis), photoluminescence and fluorescence lifetime. The results demonstrate that the deposition temperature significantly influences the morphology, thermal stability and fluorescence properties of CuQ₂. At a deposition temperature of 200 °C, the CuQ₂-C sample forms spherical micron particles with uniform morphology, enhanced thermal stability, optimal visible light absorption efficiency, and highest fluorescence intensity. The CuQ₂-C sample exhibits a maximum emission wavelength of 660 nm, a maximum excitation wavelength of 333 nm, and a fluorescence lifetime of 10.646 μs.

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Solid solutions of Ga_{(0.67–0.67x)}Co_xCr₂S₄ have been synthesized based on the cation-deficient spinel Ga_0.67Cr₂S₄ with x = 0–0.3. The structural properties of the synthesized compounds were analyzed by X-ray diffraction (XRD), which revealed that they are single-phase in spinel structure type. The surface morphology was examined using scanning electron microscopy (SEM), and it was determined that the average crystalline particle size is within the range of 0.6–1.0 µm. The EDX analysis confirmed that the composition was in compliance with the intended one and that the sample was homogeneous. A study of the structural properties revealed that the cationic vacancies and gallium ions in the spinel structure are ordered, resulting in the formation of a superstructure within the tetrahedral sublattice. Consequently, the solid solutions under investigation are classified within the (text{F}overline{4}3text{m }) space group, rather than (text{Fd}overline{3}text{m }). This study demonstrates how the magnetic properties of the investigated solid solutions are influenced by the presence of ordered vacancies. A change from paramagnetic to antiferromagnetic with weak ferromagnetism was observed for all compositions. The magnetic transition temperatures (T_N = 19–34 K for x = 0–0.3, respectively) have been determined. It has been demonstrated that the substitution of gallium by cobalt leads to an increase in the magnetic transition temperature. Furthermore, an increase in coercivity (H_C, from 1.41 to 2.62 kOe) and residual magnetization (M_R, from 0.007 to 0.034 μ_B) was observed in series with increasing cobalt concentration.

This study explores the electrochemical, thermal, and structural properties of alum as a potential material for energy storage devices, particularly capacitors and pseudocapacitors. Alum, a cost-effective and abundant material, was characterized using several advanced techniques, including thermogravimetric analysis, dynamic light scattering, and zeta-potential measurements, which provided valuable insights into its thermal stability, particle size distribution, and surface charge. Surface area analysis through the BET method revealed a specific surface area of 12.6 m²/g, highlighting the material’s porous nature. Electrochemical investigations through cyclic voltammetry demonstrated capacitive behavior with potential pseudocapacitive contributions, evidenced by observable redox peaks at scan rates ranging from 20 to 120 mV/s. The highest specific capacitance recorded was 9.48 F/g at a scan rate of 20 mV/s. Galvanostatic charge–discharge measurements confirmed charge–discharge characteristics aligned with capacitor behavior, showing a decrease in specific capacitance with increasing current density. This work underscores the potential of alum as a promising low-cost alternative for supercapacitor applications, particularly for low-power energy storage devices. With further optimization of its electrochemical performance and long-term cycling stability, alum could offer a sustainable solution for the development of efficient energy storage technologies. This study contributes to the growing international interest in sustainable materials for energy storage, addressing a significant gap in research and offering new avenues for future exploration in supercapacitor and pseudocapacitor technologies. The work aligns with global efforts to innovate cost-effective and environmentally friendly energy solutions, highlighting alum’s role in advancing the field of energy storage by providing a novel, yet accessible material with high potential for widespread application.

The antibacterial properties and corrosion resistance of magnesium-based materials are critical to the safety and reliability of medical equipment. As a promising metallic biomaterial for such applications, magnesium-based materials must address significant concerns regarding the potential for corrosion of various components and bacterial contamination in operating rooms and other medical environments. Ensuring that medical equipment remains safe and dependable is paramount, as these issues can compromise the effectiveness and integrity of the devices. This study evaluated the synergistic effects of the micro-arc oxidation (MAO) process combined with phytic acid (PA) treatment on AZ91 alloys in basic media. The assessment focused on surface topography, electrochemical response, immersion experiments, and antibacterial properties, comparing the results with those of the bare substrate and MAO-based coatings. The results indicate that adding 4 g of nano-TiO₂ per liter to the MAO electrolyte generates MgO, MgSiO₄, and TiO₂ on the surface. These compounds can act as a barrier, preventing rapid degradation and thereby slowing the corrosion rate. At 60 °C, a 60-min treatment with phytic acid (PA) yields the best corrosion resistance, which is an order of magnitude higher than that of MAO-based coatings. Furthermore, this treatment reduced the survival rate of Escherichia coli under various wavelengths of ultraviolet light.

In response to the energy crisis, researchers are working on creating novel materials for the electrodes of energy storage devices, particularly supercapacitors. Furthermore, in order to promote an environmentally friendly environment, the contamination of industrial effluent with various colors is becoming a significant problem that needs to be addressed right now. Ce-Mo co-doped NiO nanomaterials have been created for the first time to address this problem. The capacitive and photocatalytic performance of NiO was greatly influenced by the morphology, which was significantly altered by the co-doping of Ce and Mo. The characterization techniques like XRD, SEM, TEM, EDX, BET and XPS were used to investigate the specific physical properties of the as-prepared nanomaterials. CV, GCD, and EIS experiments were used to evaluate the electrochemical characteristics. CV analysis has revealed that among the various Ce and Mo co-doped NiO samples, Ce_0.05Mo_0.05NiO based on nanowires has offered the highest specific capacitance, i.e., 1108.68 F/g. The EIS studies have revealed that Ce_0.05Mo_0.05NiO nanowires are highly conductive in nature. Moreover, after 10,000 CV cycles, 85.7% capacitance retention was noted for Ce_0.05Mo_0.05NiO nanowires. The photocatalytic performance of as-prepared nanowires was assessed against the model dye methyl red (MR). During the optical study of as-prepared co-doped NiO nanomaterials, the Ce_0.05Mo_0.05NiO sample has shown a reduced optical band gap of 2.95 eV, which is very helpful for the photocatalytic conduct. The optimized Ce_0.05Mo_0.05NiO nanowires have exhibited 97% photodegradation activity against the methyl red (MR) and strong catalytic stability (88.7%). On the basis of such astonishing performance, it is suggested that the as-reported Ce and Mo co-doped NiO material based on nanowires is a potential candidate for the application in energy storage and water purification applications.

Garnet-type Li₇La₃Zr₂O₁₂ (LLZO) solid electrolytes for solid-state lithium batteries have garnered significant research interest due to their excellent lithium-ion conductivity and wide electrochemical stable window. However, the LLZO-based electrolytes still face challenges in practical applications, such as instability in solid–solid contact, surface defects, and the presence of contaminants, which lead to interface failure between the electrolyte and the electrodes. This review article presents a comprehensive overview of the LLZO-based solid electrolytes, focusing on its materials properties and interface issues. The review begins with an introduction to the crystal structure of LLZO and its Li-ion conductivity and delves into the interface between LLZO and lithium anodes, discussing physical, chemical, and electrochemical stability, as well as strategies for interface regulation. The interface between LLZO and the cathode is also examined, including interface stability and engineering. Finally, the review summarizes the current understanding of LLZO and provides an outlook for future research directions.

Revealing the high hardness mechanism of abnormal banded structure from the crystallography perspective can effectively prevent the local failure behavior of materials. In this study, the surface, 1/4 thickness (1/4 T), and center segregation samples of 70 mm thick plates for high-rise building were taken and treated at different cooling speeds (water cooling, oil cooling, air cooling). The effects of cooling rate and solute segregation on hardness were studied. The results showed that the mixed structure of lath martensite and lath bainite is formed in the surface, 1/4 T and center segregation zone (Center-SZ), and the microstructure hardness is 310 ± 10, 287 ± 10, 366 ± 17 HV, respectively. The increase in hardness was attributed to the refinement of the substructural size and the increase in the density of the large angle grain boundaries (> 15°, D_LAGBS). The analysis conducted using the Hall–Petch formula for validation and fitting led to the conclusion that the block acts as an effective structural unit for controlling hardness. The solute element segregation in the center-SZ enhances the variant selection in the phase transformation process and increases the fractions of V2, V3, and V5 variants. These variants formed block boundaries with the V1 variants, ultimately leading to a high block boundary density (> 55°, D_BBS). In addition, elements segregation increases the driving force of bainite phase transformation and decreases the driving force of martensite phase transformation, forming a high fraction of V1/V2 variant pairs in both phases. It can adjust the phase transformation strain, increase the D_LAGBS, and finally make the abnormal banded structure obtain a higher hardness value (366 ± 17 HV).