Highly effective decontamination of lead is a primary challenge for ecosystem protection and public health. Herein, we report a methodology of ternary cations intercalation to synthesize Ti3C2Tx ...MXene by structural control with angstrom-level precision through mixed fluorinated salts wet etching-alkalization approach for high-efficient lead adsorption. The successive introduction of lithium, potassium, and sodium ions continuously weakens interaction forces between Ti3C2Tx layers, resulting in achieving fine tailored interlayer distance from 9.8 to 15.9 Å. A high density of complexing groups are formed after ternary cations intercalation, which greatly improve the hydrophilicity of Ti3C2Tx to enhance the accessibility and shorten the mass transfer and provide abundant adsorption sites to exhibit strong complexing effects with lead ions. The prepared ternary cations-intercalated Ti3C2Tx nanosheets exhibited a high adsorption capacity (267.2 mg/g) toward lead ions and sharply cut down lead concentration from 10 to 0.009 mg/L, far below the drinking water standards (0.015 mg/L).
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•Ti3C2Tx MXene was achieved by mixed fluorinated salts wet etching-alkalization•Structural control with angstrom level was realized by ternary cations intercalation•High density of complexing groups exhibited strong complexing effects with lead ions•Yield of generated Ti3C2Tx was greatly enhanced compared with single Li+ intercalation
Nanomaterials; Materials structure
Materials to be used in the space environment have to withstand extreme conditions, particularly with respect to cosmic particle irradiation. We report robust stability and high tolerance of ...organolead trihalide perovskite solar cells against high-fluence electron and proton beams. We found that methylammonium and formamidinium-based lead iodide perovskite solar cells composed of TiO2 and a conductive polymer, as electron and hole transport materials, can survive against accumulated dose levels up to 1016 and 1015particles/cm2 of electrons (1 MeV) and protons (50 KeV), respectively, which are known to completely destroy crystalline Si-, GaAS-, and InGaP/GaAs-based solar cells in spacecraft. These results justify the superior tolerance of perovskite photovoltaic materials to severe space radiations and their usefulness in satellite missions.
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•Lead halide perovskites have extreme stability against electron and proton irradiations•Radiation tolerance of perovskite solar cells can exceed those of Si- and GaAs-based cells•Proton beam focused to perovskite absorber revealed high stability up to 1014 protons/cm2•Our study shows the usefulness of lightweight perovskite solar cells in satellite missions
Aerospace Engineering; Energy Materials; Materials Structure.
TC4/NiTi multi-materials structure components have been successfully fabricated via multi-wire arc additive manufacturing (MWAAM). Here we show the interface characteristics and mechanical properties ...of TC4/NiTi multi-materials structure component under bionic gradient interlayer build strategy. The results indicated that MWAAM TC4/NiTi gradient heterogeneous alloy with ultimate compression strength (1533.33 ± 26 MPa) was obtained. The excellent compression behaviour was mainly contributed to the excellent transition of gradient region indicated by EBSD analysis showing fine grain sizes and smaller difference Schmidt factor values. The phase composition from TC4 region to NiTi region had evolved with the increasing of NiTi content as follows: α-Ti + β-Ti → α-Ti + NiTi2 → NiTi2 → NiTi2 + NiTi → NiTi + Ni3Ti. The microhardness of the gradient heterogeneous alloy ranged from 310 ± 8 HV to 230 ± 11 HV, and the highest hardness value was 669.6 ± 12 HV in region B due to the precipitation of NiTi2 strengthening phase. The ultimate fracture stress and strain of sample were 1533.33 ± 26 MPa and 28.3 ± 6% respectively. The irrecoverable strain of MWAAM TC4/NiTi gradient heterogeneous alloy gradually approached 2.75% during 10 load/unload cycles of compression test.
The traditional sound absorption problem has not been completely resolved over the last 200 years. At every stage, its research has changed depending on practical requirements and current ...technologies. Phononic crystals (PCs) and acoustic metamaterials (AMs) have gained attention because of their extensive investigation and development over the past 30 years. Especially, the use of these materials brings new vitality into the traditional sound absorption problem to figure out broad working band and low-frequency absorption. This review highlights recent progress in sound absorption—from airborne to waterborne absorption—and gradient-index AMs. Progress in gradient-index AMs is singled out because of their favorable impedance matching, good viscous and thermal dissipation, and lengthened propagation paths compared with those of other materials. The progress in sound absorption of PCs and AMs is promising to serve as the next-generation sound absorbing materials, trap and reuse acoustic energy, and attenuate earthquake/tsunami wave in the future.
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Acoustics; Materials Design; Materials Structure; Metamaterials
Perovskite solar cells (PSCs) have achieved extremely high power conversion efficiencies (PCEs) of over 25%, but practical application still requires further improvement in the long-term stability of ...the device. Herein, we present an in situ interfacial contact passivation strategy to reduce the interfacial defects and extraction losses between the hole transporting layer and perovskite. The existence of PbS promotes the crystallization of perovskite, passivates the interface and grain boundary defects, and reduces the nonradiation recombination, thereby leading to a champion PCE of 21.07% with reduced hysteresis, which is one of the best results for the methylammonium (MA)-free, cesium formamidinium double-cation lead-based PSCs. Moreover, the unencapsulated device retains more than 93% and 82% of its original efficiencies after 1 year's storage under ambient conditions and thermal aging at 85°C for 1,000 h in a nitrogen atmosphere, likely due to the usage of MA-free perovskite and the enhanced surface hydrophobicity.
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•An in situ interfacial defects contact passivation strategy has been developed•PbS quantum dots were used as the passivant to reduce the traps of perovskite films•The methylammonium-free device with passivation layer gives efficiency over 21%•The unsealed device demonstrated excellent ambient and thermal long-term stability
Electrochemical Energy Storage; Energy Materials; Devices; Materials Structure
Sodium thioantimonate (Na3SbS4) and its W-substituted analogue Na2.88Sb0.88W0.12S4 have been identified as potential electrolyte materials for all-solid-state sodium batteries due to their high Na+ ...conductivity. Ball milling mechanochemistry is a frequently employed synthetic approach to produce such Na+-conductive solid solutions; however, changes in the structure and morphology introduced in these systems via the mechanochemistry process are poorly understood. Herein, we combined X-ray absorption fine structure spectroscopy, Raman spectroscopy, solid-state nuclear magnetic resonance spectroscopy, powder X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy characterization techniques to provide an in-depth analysis of these solid electrolytes. We report unique changes seen in the structure and morphology of Na3SbS4 and Na2.88Sb0.88W0.12S4 resulting from ball milling, inducing changes in the electrochemical performance of the solid-state batteries. Specifically, we observed a tetragonal-to-cubic crystal phase transition within Na3SbS4 following the ball mill, resulting in an increase in Na+ conductivity. In contrast, the Na+ conductivity was reduced in mechanochemically treated Na2.88Sb0.88W0.12S4 due to the formation and accumulation of a WS2 phase. In addition, mechanochemical treatment alters the surface morphology of densified Na2.88Sb0.88W0.12S4 pellets, providing intimate contact at the solid electrolyte/Na interface. This phenomenon was not observed in Na3SbS4. This work reveals the structural and morphological origin of the changes seen in these materials’ electrochemical performance and how mechanochemical synthesis can introduce them.
Tissue engineering of the annulus fibrosus (AF) is currently being investigated as a treatment for intervertebral disc degeneration, a condition frequently associated with low back pain. The ...objective of this work was to use 3D printing to generate a novel scaffold for AF repair that mimics the structural and biomechanical properties of the native tissue. Multi-layer scaffolds were fabricated by depositing polycaprolactone struts in opposing angular orientations, replicating the angle-ply arrangement of the native AF tissue. Scaffolds were printed with varied strut diameter and spacing. The constructs were characterized morphologically and by static and dynamic mechanical analyses. Scaffold surfaces were etched with unidirectional grooves and the influence on bovine AF cell metabolic activity, alignment, morphology and protein expression was studied
in vitro
. Overall, the axial compressive and circumferential tensile properties of the scaffolds were found to be in a similar range to the native AF tissue. Confocal microscopy images indicated that cells were able to attach and spread on the smooth polycaprolactone scaffolds, but the surface texture induced cellular alignment and proliferation. Furthermore, immunofluorescence analysis demonstrated the aligned deposition of collagen type I, aggrecan and the AF-specific protein marker tenomodulin on the etched scaffolds. Overall, results demonstrated the potential for using the scaffolds as a template for AF regeneration.
Air-to-air missile is an important weapon for aircraft to gain the superiority of air control combat. With the development of overall design technology and the promotion of operational use ...requirements, air-to-air missile will fly farther and farther and face the problem of penetration. Stealth capacity is crucial for the missile penetration. Stealth material is an important carrier and key technology for air-to-air missile stealth, and also an important part of its structure design. This paper analyzes the current research status of stealth materials and intelligent stealth technology in visible light, infrared, radar and other technical fields, and puts forward the development focus of intelligent stealth technology in the next stage.
Nature does nothing in vain. Through millions of years of revolution, living organisms have evolved hierarchical and anisotropic structures to maximize their survival in complex and dynamic ...environments. Many of these structures are intrinsically heterogeneous and often with functional gradient distributions. Understanding the convergent and divergent gradient designs in the natural material systems may lead to a new paradigm shift in the development of next-generation high-performance bio-/nano-materials and devices that are critically needed in energy, environmental remediation, and biomedical fields. Herein, we review the basic design principles and highlight some of the prominent examples of gradient biological materials/structures discovered over the past few decades. Interestingly, despite the anisotropic features in one direction (i.e., in terms of gradient compositions and properties), these natural structures retain certain levels of symmetry, including point symmetry, axial symmetry, mirror symmetry, and 3D symmetry. We further demonstrate the state-of-the-art fabrication techniques and procedures in making the biomimetic counterparts. Some prototypes showcase optimized properties surpassing those seen in the biological model systems. Finally, we summarize the latest applications of these synthetic functional gradient materials and structures in robotics, biomedical, energy, and environmental fields, along with their future perspectives. This review may stimulate scientists, engineers, and inventors to explore this emerging and disruptive research methodology and endeavors.
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Biomaterials; Materials Structure; Materials Design
Investigating the rheology of 2D materials such as clays is of growing interest in various applications as it dictates their flowability and structural stability. Clay minerals present unique ...rheological properties, especially when in suspension. This study explores the effect of functionalizing bentonite clay with betaines of variable carbon chain lengths on the rheological properties of clay slurries to analyze their interactions in suspension. The results show that these zwitterion-functionalized clays exhibit higher viscosity, storage moduli, and flow stresses due to the formation of three-dimensional networks and increased aggregation caused by intercalation. The structural properties of the clay slurries are also found to be pH-sensitive. Additionally, XRD and SEM analyses support the proposed intercalation of the clays. The findings suggest the potential application of small-chain betaine functionalized clays in engineering and energy applications. Overall, this study provides insight into predicting the stability and strength of functionalized clay suspensions.
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•Bentonite slurries have been functionalized with betaines•Interactions between the betaines and clay on rheology have been investigated•Intercalation and rearrangement of molecules depend on betaine carbon-chain length•Clays functionalized with C1 betaine exhibited the most desirable characteristics
Materials testing; Materials structure; Materials science engineering
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