Advanced Composites and Hybrid Materials最新文献

With the increasing use of aluminum-rich (Al-rich) supplementary cementitious materials (SCMs), clarifying the roles of aluminum in C-A-S-H gels and in surplus Al-rich phases is critical for assessing chloride resistance. An Al-rich C-A-S-H material was synthesized under precise stoichiometric conditions and exposed to accelerated chloride ingress for up to 120 days. The evolution of phase assemblage, gel chemistry and physicochemical properties was monitored during the exposure. A time-dependent model was developed to describe chloride ingress and binding. Chloride ion binding in the Al-rich C-A-S-H occurred through both chemical solidification in Friedel’s salt and physical adsorption, with physical adsorption on C-A-S-H surfaces being dominant, accounting for approximately 60–70% of total bound chloride. The Al-rich phase primarily acted as a “reservoir,” releasing Ca²⁺ and Al³⁺ which facilitated the formation of Friedel’s salt and promoted the subsequent formation of C-A-S-H gel. Furthermore, the subsequent re-incorporation of aluminum into the C-A-S-H gel under chloride leading to a partial transformation from cross-linked to non-cross-linked silicate chains. This structural evolution is accompanied by a marked micromechanical degradation, with the Young’s modulus decreasing from 11.1 to 6.9 GPa under highly accelerated, severe exposure conditions. Overall, these results provide a time-resolved mechanistic picture of how C-A-S-H gel and surplus Al phases co-evolve under chloride attack, offering a new basis for the durability design of SCM-rich cementitious composites.

Advanced military equipment increasingly demands materials with acoustic, electromagnetic, and infrared stealth properties, yet existing materials are unable to achieve effective multispectral stealth. Based on a multistage porous structure design concept, this study develops an aramid nanofiber (ANF)/flake carbonyl iron powder (FCIP)/polydopamine@biomass porous carbon (PC) composite aerogel (AFPC). This material exhibits not only efficient acoustic, electromagnetic, and infrared multispectral stealth compatibility but also maintains favorable mechanical properties. We constructed a “directional pore channels - multistage pores - heterogeneous interfaces” architecture across macro‑to‑micro scales. Macroscopically, ice-templating regulates the aligned arrangement of ANFs, establishing a directional pore skeleton with low propagation impedance. Mesoscopically, thermodynamic control modulates the porous conductive network of PC to enhance energy dissipation and suppress thermal conduction. Microscopically, FCIP tailors magnetoelectric heterogeneous interfaces to strengthen electromagnetic wave polarization loss, while utilizing the metal’s “mirror-reflection” effect for infrared multireflection. The AFPC aerogels integrate highly efficient multispectral stealth performance, demonstrating noise reduction coefficient of 0.73 (30 mm), minimum reflection loss of -71.53 dB (30 mm), absorption bandwidth of 15.8 GHz (30 mm), thermal conductivity of 46 ~ 48 mW/m·K (10 mm), and infrared emissivity of 0.31 ~ 0.33 (10 mm). These properties significantly surpass those of previously reported multispectral stealth aerogels. This design establishes a paradigm for developing highly efficient multispectral stealth materials, showing substantial potential for advanced military applications.

Electromagnetic waves management in electronic equipment is an important premise to ensure the efficient and stable operation of components. In this work, aimed at the 2–18 GHz frequency spectrum, a novel theoretical framework for achieving effective absorption (reflection loss < -10 dB) is established and applied to deduce the ideal ranges of permittivity, input impedance, and attenuation constant for arbitrary thicknesses. Guided by the ideal electromagnetic parameter qualification model, multiphase composites with complex dielectric characteristics are constructed, which are composed of 3D graphene skeleton, SiC interface, and SiBCN matrix, to verify the regulation of the electromagnetic properties. Based on electric field simulation, the permittivity, microstructure, and composition of the composites are systematically predicted, regulated, and optimized. Therefore, the enhanced absorption performance can reach a minimum reflection loss of -39.4 dB and a maximum effective absorption bandwidth of 2.96 GHz. Furthermore, a new empirical permittivity mixing model which can suit the composites is preliminarily developed, demonstrating excellent permittivity prediction accuracy. This work provides a paradigm shift in microwave compatibility and management in electronic components through coupled theoretical-experimental advancement.

The hydrothermal method presents significant advantages in terms of low cost, environmental sustainability, and high efficiency for the corrosion protection of magnesium alloys. However, the experimental stability and protection performance can be restricted by specific details of technologic process such as the direction of sample placement and defects in coating encapsulation. This study synthesized a composite coating comprising Mg(OH)₂-CaSiO₃/CaCO₃ and proposed a synergistic optimization strategy based on multi-physics field to address these issues. By constructing a joint simulation model using Fluent-transient structure analysis, the mechanism behind coating defects caused by the eddy current effect in the reactor and the geometric stress concentration of the sample was elucidated. A synergistic approach involving chamfering and horizontal placement was developed to achieve complete coating encapsulation. The results indicate that the dense Mg(OH)₂ bottom layer effectively inhibits charge transfer, while the CaSiO₃/CaCO₃ surface composite layer extends the diffusion path for corrosive media. The polarization resistance of the optimized sample reaches 4.06 × 10⁹ Ω·cm², with corrosion current density reduced by five orders of magnitude compared to that of bare substrate. After 168 h of immersion testing, the coating continued to provide effective protection. The corrosion product Mg(OH)₂ has been shown to continuously fill the micropores. forming a secondary protective layer. The integrated approach, combining simulation, mechanism and process optimization, contributes to significantly expanding the industrial application for protective coatings on magnesium alloys.

Regulating the solvation structure toward anion-derived complex is crucial for building an inorganic-rich solid-state electrolyte interface (SEI) utilized as a dendrite-free lithium anode. Introducing porous materials into the separator is an effective strategy to promote the desolvation of solvated ions as they traverse the pores, thereby addressing key interfacial challenges. Micropores enable effective desolvation; however, they restrict Li⁺ ion mobility. Herein, for the first time, mesoporous boehmite (γ-AlOOH with an average pore size of 3.45 nm) is used to regulate the solvation structure and achieve multifunctional synergy. Typically, the BP/GF separator achieves a Li⁺ ion transference number of 0.61, superior flame retardancy, and an inorganic-dominated SEI (enriched with Li₂CO₃, Li₃N, Li₂O, and LiF), because the hydroxyl groups on boehmite establish hydrogen bonds with solvent molecules and anions, which effectively promote the desolvation and confine free anions, leading to an increase in anion-derived complex and enhancement of Li⁺ ion transport kinetics, and finally collectively mitigate dendrite formation and stabilize the lithium metal anode. Furthermore, mesoporous boehmite universally regulates solvation structure modulation across Li-S, Li-LiFePO_4, and Li-O₂ batteries, enabling broad-spectrum performance improvements.

Bismuth oxychloride (BiOCl) has been prevalently applied in UV-photodetection due to its wide band gap. However, further application is hindered by its low light utilization efficiency and fast carrier recombination. In this work, a 2D-2D Ti₃CN@BiOCl heterojunction was constructed to broaden the light absorption and increase the carrier mobility. A small amount of hole scavengers was utilized to suppress the carrier recombination. According to DFT calculations, the electron transfer occurs from MXene to BiOCl and is subsequently converted into an electrical signal. The photo-response performance of Ti₃CN@BiOCl was systematically investigated, where an optimized photocurrent density as high as 47.17 µA∙cm^− 2 and a photoresponsivity of 12.50 mA/W could be achieved. Furthermore, Ti₃CN@BiOCl was found to exhibit a broad-band and fast response (~ 0.04 s), and excellent long-term stability (~ 0.005% decrement for each cycle). This work highlights promising prospects of Ti₃CN@BiOCl heterojunctions for use in photodetection, which also hold great potential for other types of optoelectronic devices.

Structural engineering of electromagnetic wave absorbing (EMWA) materials faces critical challenges in scalable fabrication and multifunctional integration. Herein, a flexible and sustainable bamboo-based composite (BMXMo) featuring engineered microcapacitor-Schottky heterostructures is proposed to synergize ultra-efficient K-band microwave absorption with self-powered health monitoring. The heterostructure is constructed by assembling conductive Ti₃C₂T_x MXene electrodes and 1T/2H-MoS₂ dielectric nanoflowers within a densified bamboo matrix. The heterostructure optimizes impedance matching while enhancing multi-scale polarization via interfacial/dipolar effects and Schottky-modulated charge trapping. The optimized BMXMo₅₅ film exhibits exceptional EMWA performance, with an ultra-high reflection loss of − 52.05 dB and a broad effective absorption bandwidth of 7.95 GHz (covering 18–26 GHz). Moreover, the mechanical flexibility and unique microcapacitor-Schottky structure enable efficient surface charge modulation, allowing the direct fabrication of high-performance triboelectric nanogenerators (TENGs). The resulting BMXMo-TENG devices generate an open-circuit voltage of 81.8 V and a power density of 6.4 µW cm⁻², sufficient to drive commercial electronics. Furthermore, an integrated self-powered sensing system is demonstrated for real-time and precise monitoring of various physiological signals, including respiratory rhythms, joint kinematics, and micromotions. This work pioneers a sustainable platform for multifunctional wearables in electromagnetic-heavy environments, unifying high-efficiency EMWA with autonomous biosensing.

Graphical Abstract

Recovery of rare earth elements (REEs) from industrial waste is a glorious channel for waste to resource transformation. Herein, Zn-BDC-graphene oxide composite (Zn-BDC@GO) was crafted via combining terephthalic acid ligand (BDC) coordinated to Zn²⁺ center (Zn-BDC) and graphene oxide (GO) to recover Pr(III) from aqueous solution. Recovery performance was optimized using response surface methodology (RSM). Speciation resolved adsorption mechanism was clarified via amalgamating Zn-BDC@GO and Pr(III) speciation, statistical thermodynamics, isotherms and kinetics, as well as multifarious spectroscopy. Result delivers, Zn-BDC@GO renders Pr(Ⅲ) recovery efficiency superior to either GO or Zn-BDC. The maximum mono layer adsorption capacity given by the Langmuir model is 436.68 mg·g^− 1 at pH 6, dosage 500 mg·L^− 1 and contact time 60 min. RSM clarifies the optimum Pr(III) recovery percent as 99.583% under pH 6.852, Zn-BDC@GO dosage 582.197 mg·L^− 1 and contact time 54.017 min. Moreover, Zn-BDC@GO can effectively recover Pr(Ⅲ) from binary lanthanides Pr/Sm, Pr/Eu, Pr/Gd with high selectivity coefficient 24.74, 60.46, 122.77, respectively, exhibiting exceptional selectivity. Statistical thermodynamic functions including enthalpy, Gibbs free energy, entropy, etc., unveil that adsorption is exothermic, spontaneous and randomness increasing. Isotherm and kinetic fittings uniformly designates favorable chemisorption controlled by surface reaction. Speciation and versatile spectroscopy (FTIR, Raman, fluorescent, XPS) reveal that Pr(Ⅲ) is attached to COO, C-O-C, C-C and C = C mainly in the form of Pr³⁺ via electrostatic attraction and electron transfer to yield maximum adsorption at pH = 6. This work illuminates the adsorption behaviour and mechanism of Pr(Ⅲ) over Zn-BDC@GO, as to shed light on developing MOFs based materials for REEs recovery.

The global food crisis is worsening owing to severe losses in the fruit and vegetable supply chain, driven by rapid population growth, geopolitical conflicts, and environmental challenges. This review primarily addresses the requirements of the fruit and vegetable supply chain and investigates the functional properties of biomimetic materials as potential solutions to the challenges faced. These materials provide advanced postharvest preservation solutions through hydrophobicity, adhesion, self-healing, enhanced mechanical properties, and microbial inhibition. They also have the potential to mitigate losses caused by cold chain fluctuations and transportation vibrations. Furthermore, their integrated sensing and stimulus-responsive capabilities enable autonomous problem resolution. A theoretical framework has been established for the future development and optimization of biomimetic materials in the fruit and vegetable supply chain, with proposed pathways to reduce waste and enhance food safety. These developments highlight the potential of biomimetic materials to transform supply chain management and mitigate food losses.

Graphical abstract

Digital light processing (DLP) 3D printing enables fabrication of complicated geometries, but the intrinsically insulating properties of photocurable polymeric resins have limited their electrical functionalities. Here we report an exceptionally high electrical conductivity (σ = 341 Scm^-1) using a novel Ag⁺ ion resin, synthesized by incorporating AgNO₃ into PEGDA-based resin. The small Ag⁺ ion (~ 0.1 nm) maintains stable dispersion in solution, significantly reducing UV scattering/absorption and increasing penetration depth (797.1 μm), compared with the resin where solid particles are dispersed. The photopolymerization of the resin and thermal reduction of Ag⁺ to Ag⁰ are carried out independently. The photopolymerization constructs complicated geometries with high resolution. The subsequent vacuum thermal reduction at 180 ℃ generates uniformly dispersed Ag nanoparticles. The Ag⁺ ion resin (Ag = 18 vol%) enables construction of highly conductive electrical components (σ = 341 S cm^-1), with the significantly larger UV penetration depth (797.1 μm) and fast exposure time (1.5 s/layer for layer thickness of 25 μm), compared with DLP 3D printing reports in literature. The σ is also invariant for 9 months.