Advanced Composites and Hybrid Materials最新文献

Nanodielectric systems based on a high glass-to-rubber transition temperature (T_g) epoxy resin modified with laponite® (Na⁺_0.7[(Si₈Mg_5.5Li_0.3)O₂₀(OH)₄]^–0.7) cylindrical nanoparticles were developed and examined as dielectric materials for capacitive energy storage applications. Laponite is an inexpensive synthetic nanoclay that has recently gathered attention as potent electrode material for batteries, due to its high specific surface area and ionic groups. The dielectric properties of the developed nanocomposites were investigated extensively by means of broadband dielectric spectroscopy (BDS), which revealed intense Maxwell–Wagner-Sillars interfacial polarisation (MWS-IP) phenomena at the organic/inorganic interface and an additional dielectric process that showed a strong dependence on the nanoclay concentration, thus attributed to laponite (IDE). It was also found that the presence of laponite significantly altered the temperature dependence of MWS-IP, leading to an enhancement in relaxation times at higher temperatures. The observed phenomenon is attributed to less mobile, adsorbed polymer fragments entrapped between two or more laponite nanoparticles that alters the interphase between the particle and the epoxy. MWS-IP was observed to obey the Barton-Nakajima-Namikawa relation with the dc conductivity values being indicative that both phenomena are associated with the same charge carriers, at different timescales. Moreover, the cycle life performance of epoxy/laponite nanodielectrics was also examined at 30 °C and 120 °C conducting charge/discharge measurements in dc conditions. The addition of laponite nanoparticles endowed the nanodielectric systems with significantly improved capacitive energy efficacy.

The solid-state transformer (SST) in the renewable energy grid is developing in the way of high voltage and high frequency, which often results in a sharp increase in heat production of the equipment and accelerates the failure of the insulating materials. Epoxy resin (EPR) is commonly used as an insulation material for SST due to its excellent electrical insulating properties, processing performance (viscosity), and low price. However, the thermal conductivity of EPR is only about 0.2 W/(m·K), which leads to poor insulating performance under high frequency and temperature. To enhance thermal conductivity, a substantial quantity of highly thermally conductive particles is incorporated into the EPR, accompanied by a severe increase in electrical insulation defects and viscosity. This study utilized a multi-scale particle-filled approach to investigate the thermal conductivity, processing characteristics, and high-frequency electrical insulation performance of composites. The composite, filled with 25 µm BN and 5 µm SiO₂ particles, enhances thermal conductivity to 0.732 W/(m·K) and demonstrates superior electrical insulating properties at both 10 kHz and 20 kHz bipolar square waves (with an increase of 131.76% and 163.97% in relative EPR, respectively), as well as good processability. Meanwhile, it is found that the dielectric loss, thermal conductivity, and electric field distribution of the composite are the main factors affecting the electrical insulating properties from 10 to 20 kHz under high voltage.

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The post-industrial revolution era has witnessed unprecedented economic and technological growth, leading to a significant surge in population and industrial advancements. However, this rapid progress has been accompanied by a concerning increase in environmental degradation, resulting in mass extinctions and posing a serious threat to both ecosystems and human health. Addressing these pressing challenges requires innovative solutions. Metal-organic frameworks (MOFs), which are crystalline structures made of metal ions or clusters interwoven with organic ligands, are one intriguing technique. MOFs have gotten a lot of interest because of their amazing specific surface area, tunable pore size, and adaptability. Their development holds significant potential for mitigating industrial waste gas emissions and improving environmental quality across various applications. This comprehensive review delves into the pivotal role of MOFs in air purification. Beginning with an exploration of the hazards, origins, and complexities of haze, the review meticulously examines the applications of MOFs in addressing various pollutants, including SO₂, NO_x, PM_2.5, automobile exhaust, coal-fired flue gas, fuel emissions, and incineration byproducts. Each section provides insight into design principles, adsorption mechanisms, and transformation processes for effective pollutant mitigation. Overall, this review demonstrates an array of effective and environmentally sound technical methodologies, underscoring the pivotal role of MOFs in combating multifaceted air pollution. It serves as a valuable resource for researchers and practitioners seeking sustainable solutions to complex environmental challenges.

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Core–shell structured Fe₃O₄@PANI composite was prepared using a chemical oxidation polymerization method and used as the bio-carrier to enhance the biotransformation of waste activated sludge to produce medium-chain fatty acid by anaerobic fermentation. The synthesized composite had stable chemical properties and good biological affinity. The addition of Fe₃O₄@PANI can effectively promote the acidogenesis and chain elongation in the fermentation system. When 1 g/L of Fe₃O₄@PANI was added, the acid production from the fermentation system increased by up to 1.9 times, and the maximum acid production rate increased by 3.4 times. Meanwhile, the production of caproate increased by 2.79 times. It was demonstrated that the added Fe₃O₄@PANI facilitated the release of organic compounds from bacterial cells and improved the electrical activity of the sludge system, thereby accelerating the chain elongation to generate caproate. Moreover, the addition of Fe₃O₄@PANI can effectively enrich the functional microbes related to chain elongation, including Clostridium sensu stricto 12, Dechloromonas, Romboutsia, and IMCC26207.

Due to the abundant terrestrial storage of raw materials, tin sulfide stands out as one of the most promising candidates for anodes in lithium-ion batteries (LiBs). Among its various forms, Tin trisulfide (Sn₂S₃) is a n-type semiconductor with notable anisotropic electrical conductivity. However, research on Sn₂S₃ crystal materials and their utilization as anode materials in LiBs remains limited. To expand the scope of application research involving Sn₂S₃ anode materials and to address the efficiency shortcomings associated with tin sulfide, a novel stacked leaf-like Sn₂S₃@C/Ti₃C₂T_x anode material has been meticulously designed and synthesized. Employing mechanical ball milling, the negatively charged surface of the Ti₃C₂T_x material is strategically leveraged to create defect spaces. These spaces facilitate a more stable anchoring of Sn₂S₃@C onto the sheet-like surface, mitigating internal stresses that may arise during charge–discharge cycles due to material aggregation. When deployed as the anode in LiBs, the Sn₂S₃@C/Ti₃C₂T_x composite exhibits exceptional cycling stability and conductivity. Notably, it demonstrates high reversible specific capacities across various current densities, i.e., 1162, 996.8, 925.4, 866.4, 810.1, 721.4, 624.5, and 552.8 mAh g⁻¹ at 0.1, 0.2, 0.5, 1, 2, 4, 8, and 10 A g⁻¹, respectively, surpassing those reported for SnS_x-based anodes for LiBs. Additionally, dynamic tests such as galvanostatic intermittent titration technique (GITT) reveal that Sn₂S₃@C/Ti₃C₂T_x possesses superior surface diffusion capability and rapid electrical conduction rates. These findings underscore the significant potential for the practical application of Sn₂S₃@C/Ti₃C₂T_x nanocomposites in high-performance LiBs, offering a promising avenue for advancing battery technology towards enhanced efficiency and reliability.

The semiconductive cadmium sulfide (CdS) nanoparticles were coated on the surface of Methanosarcina barkeri (M. barkeri) by self-assembly method to form the M. barkeri-CdS biohybrid in this work. It proved to be an effective and selective catalyst for the solar-driven conversion of CO₂ to CH₄, enabling the upgrading of biogas from anaerobic digestion. The physicochemical properties of the synthesized biohybrid were characterized, and the effect of various conditions on the CH₄ production of the biohybrid was also investigated. It was revealed that the CdS dosage, pH, cysteine, and concentration of sodium bicarbonate were key factors influencing the performance of the biohybrid. Additionally, it was observed that CH₄ was produced under both light and dark conditions. Finally, the mechanisms involved in the CH₄ production by the biohybrid under light and dark conditions were discussed.

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Methanosarcina barkeri–cadmium sulfide biohybrid can effectively convert carbon dioxide to methane, achieving biogas upgrading.

Tin (Sn) micro-nanoparticles with special pine tree dendritic morphology were synthesized by using tin foil as the anode and titanium as the cathode through simple anodization method. Surprisingly, it is found that the morphology of Sn particles is closely related to factors such as the type of electrolyte, the concentration of the electrolyte, and the different applied voltages, and briefly discussed the influence of various factors on the growth of Sn particles. In addition, Sn particles are calcined under different temperature conditions to obtain Sn/SnO₂ hybrid materials with different tin dioxide (SnO₂) contents. The changes in morphology and the phase of SnO₂ crystal lattices were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively, which proved the successful synthesis of Sn/SnO₂ mixed materials. Finally, the Sn/SnO₂ hybrid material with metal-doped modified semiconductor properties was used to photocatalytic degradation of simulated organic pollutants rhodamine B (RhB). It was found that the photocatalytic degradation efficiency of the Sn/SnO₂ hybrid material under simulated sunlight conditions is near 90% in 5 h. Therefore, this work provides a convenient and effective environmental protection approach for the treatment of architecture and industrial dyes.

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Tin (Sn) micro-nanoparticles with special pine tree dendritic morphology are synthesized through simple anodization method, and the final product Sn/SnO₂ particles after different heat treatments show superior photocatalytic degradation of RhB under simulated solar light.

Electroconductive ceramics were a class of materials that exhibited metal-like conductivity while also retaining the beneficial properties of ceramics. Currently, they were ceramic composites generally fabricated by sintering ceramic powders with conductive additives such as graphene or single-wall carbon nanotubes, which were expensive and often suffered from poor dispersibility and low performance. To address these issues, we developed a novel and facile sol–gel approach for synthesizing electroconductive ceramic composites. In this work, we have successfully synthesized high-entropy metallic (Ti, Mg, Al, Zr) oxide ceramic composites using cost-effective organic metallic coupling agents in a “one-pot” synthesis. Subsequent thermal sintering produced the ceramic composites with dramatically reduced resistivity through the creation of oxygen vacancies and homogeneous in situ graphitization. The resulting electroconductive ceramic composites also possessed remarkable mechanical properties, photothermal conversion ability, and biocompatibility. To the best of our knowledge, this was the first time that electroconductive high-entropy ceramic composites have been synthesized using organic metallic coupling agents. This work offered new potential for the fields of electro-discharge machining (EDM) processing, electronics, energy, solar-driven photothermal engineering, and biomedical industries, allowing easy and inexpensive production of electroconductive ceramic composites with unique properties.

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Nanofibers, due to the characteristics of high porosity, large specific surface area, and high strength and mechanical flexibility, exhibit a great potential for gas sensing as a sensing layer or versatile support. The abundant compositions, specific morphology, and tunable pore size of nanofibers are suitable for the detection of diverse environmental gases, and its excellent flexibility and mechanical properties are convenient for fabricating the smart and wearable electronic devices. Compared with conventional powder materials, these merits of nanofibers mainly can enhance the sensitivity and stability. In this review, we first introduce the main evaluation parameters for gas sensors, the designed principle of sensors, and the advantages of nanofiber materials for gas sensing. Then, the recent advances in nanofiber-based gas sensors for monitoring the different environmental gases, mainly including hydrogen (H₂), methane (CH₄), carbon monoxide (CO), acid gases (H₂S, NO₂, and SO₂), SF₆ and its decomposition products, chemical warfare agents (CWAs), and volatile organic compounds (VOCs), are summarized. Meanwhile, the sensing mechanism and different sensing materials based on noble metals, metal oxides, metal-organic framework, and their composites are discussed comprehensively. Finally, the challenges and perspectives of nanofiber-based gas sensors are also addressed.

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By structural design, a new type of highly functional ionic liquid (NHFIL) was synthesized by combining 1-vinylimidazole with tris(2-chloroethyl) phosphate through a one-pot method. When it is melted into the polymer composite, the highly reactive vinyl of NHFIL promotes the cross-linking within the polymer system to enhance the compatibility between the inorganic filler and polymer matrix and further improve the mechanical properties of the composite, additionally, the N and P elements would generate non-flammable gas phase and carbonized layer during combustion, which endows the polymer composites with remarkable flame-retardant performance. On this basis, the low-smoke flame retardant ethylene–vinyl acetate (EVA)-based composites were prepared by introducing NHFIL into the industrial formula of the cable sheath material for maglev trains. The effects of the composition and molecular structure of NHIFL on the interfacial compatibility, microstructure, mechanical properties, and flame retardancy of composite materials have been studied in detail. The results indicate that with the addition of NHFIL, the cross-linking degree, gel content, thermal stability, mechanical properties, oil resistance, and the flame retardancy of the EVA-based composites were comprehensively improved. Significantly, with a low addition of 3.5% NHFIL, the gel content reaches 90.3%, the carbon residue reaches 42.7%, and the limiting oxygen index (LOI) reaches 36.3%, and surprisingly, the oil resistance increased by five times, which endows the composites with great application potential in cables of major transportation equipment.