Expanding the functionality of 3D magnetic nanostructures requires precise control over competing anisotropy contributions. Here, we fabricate bisegmented Co–Ni “jellyfish” nanowires with tailored segment arrangements, exploiting Co’s strong magnetocrystalline anisotropy and Ni’s dominant shape anisotropy. We uncover a unique magnetic duality: Co segments can be tuned to exhibit either a flux closing multidomain state or a shape anisotropy dominated vortex configuration, directly governed by their geometry. This local domain structure suppresses magnetostatic interactions in nanowire arrays - reducing the interaction field from 1090 Oe (homogeneous Ni) to approximately 700 Oe - despite Co’s higher saturation magnetization. Magnetic force microscopy directly visualizes the flux closing state, while micromagnetic simulations elucidate the underlying spin configurations. Furthermore, we demonstrate that the engineered domain structure enables programmable anisotropic magnetoresistance (AMR) in individual nanowires, achieving a maximum ΔR/R of 1.0% with a distinct two step switching signature in bisegmented Co/Ni nanowires - features promising for multi-level data storage. This work establishes a design blueprint for functional magnetic nanomaterials where strategic anisotropy control dictates both static and dynamic properties, advancing 3D nanomagnetism toward high density spintronic memory and neuromorphic computing applications.
Marine biofouling poses serious safety risks to offshore infrastructures and leads to substantial economic losses. Although hydrogels have shown significant promise in marine antifouling applications, developing antifouling hydrogels that simultaneously possess excellent mechanical strength and strong antifouling efficiency remains a major challenge. Herein, a high-performance antifouling hydrogel was constructed by incorporating hollow glass microspheres functionalized with a Cu(I) based metal-organic framework (Cu(I)-MOFs) into a poly(vinyl alcohol)/ poly(sulfobetaine methacrylate) (PVA/PSBMA) double-network matrix. The as-developed Cu(I)-MOFs/hydrogel composite integrates excellent antifouling and mechanical properties, achieving protein and algal resistance of 99.8% and 99.9%, respectively, as well as a high antibacterial rate of 99.6%. Importantly, the composite reaches a compressive strength of 5.35 MPa, outperforming many existing antifouling hydrogels, and demonstrates low swelling with reliable performance in seawater. In a 100-day field test in a real marine environment, the fouling coverage of as-prepared hydrogel was as low as 0.12%. This work offers an effective and feasible strategy for preventing marine biofouling and also pioneers a new approach for hydrogel applications.
With the miniaturization of two-dimensional transition metal dichalcogenide electronic devices to the submicron scale, electrical breakdown and thermal breakdown become more likely to occur. Clarifying the breakdown mechanism of two-dimensional semiconductor materials is essential for reliable application of micro- and nanoelectronics. This work investigates the size-dependent breakdown characteristics of MoS2 field-effect transistors and reveals a transition in breakdown mechanism that is governed by channel length. In short-channel devices (≤ 0.8 μm), reduced thermal conductivity elevates the channel temperature and narrows the bandgap, leading to tunneling-dominated breakdown under high electric fields. For longer channels (≥ 1.5 μm), recovered thermal conductivity and enlarged heat-dissipation area lower the device junction temperature and reduce carrier tunneling, and the breakdown mechanism shifts to avalanche multiplication. This research provides insights into the thermal and electrical characteristics of two-dimensional materials and advances the reliability analysis of two-dimensional electronics.
Photocatalytic water splitting is crucial for tackling energy shortages and environmental pollution. Janus materials, with their asymmetric structures and intrinsic electric fields, are highly valued for this purpose. Through first-principles calculations, we examine Janus M2XYZ (M=Bi, Sb; X/Y/Z=S, Se, Te; X≠Y≠Z) monolayers and reveal their robust structural stability, band gaps of 1.11-1.75 eV at the HSE06 level (reduced below 1.23 eV upon inclusion of spin-orbit coupling), strong absorption of visible-to-ultraviolet light, and elevated carrier mobility (electrons: 103 cm2·V-1·s-1; holes: 102 cm2·V-1·s-1). The corrected solar-to-hydrogen (STH) efficiencies—calculated as theoretical optical absorption limits—surpass 24 %, with Sb2SSeTe achieving 28.80 %. Mechanistically, the kinetics of the hydrogen evolution reaction (HER) are influenced by the adsorption strength of the X-layer, while the oxygen evolution reaction (OER) activity is enhanced by the presence of a built-in electric field. Notably, we establish a linear relationship between the difference in surface electronegativity and built-in electric field (ΔΦ ∝ Δχ), providing a straightforward descriptor for the rational design of Janus-based heterostructures.
The aggressive implementation of fast charging protocols in high-energy-density lithium-ion batteries severely intensifies internal Joule heating, triggering a hazardous electro-thermal-fire trilemma. Traditional organic phase-change materials (PCMs) offer an attractive energy-free cooling route but suffer from low thermal conductivity, liquid leakage, flammability, and poor electrical insulation. Herein, a leaf-vein-inspired anisotropic phase-change composite material (CPCM) is fabricated via an elegant, pre-modification-free in-situ alkaline activation and directional ice-templating strategy. By leveraging the residual nucleophilic hydroxyl ions natively dwelling within the strongly alkaline aramid nanofiber (ANF) slurry, the unpassivated edge defects of pristine boron nitride nanofibers (BNNFs) undergo a spontaneous interfacial chemical reconstruction. This in-situ reaction matures an extensive hydrogen-bonding network and mechanical interlocking with neighboring ANF backbones, structurally locking them into highly aligned, vertical lamellar cell walls. Benefiting from continuous vertical phonon highways, the engineered CPCM delivers an outstanding out-of-plane thermal conductivity of 1.12 W/(m·K) while preserving a premium latent heat density of 216.9 J/g with an elite cycling enthalpy retention of 96.58% across 400 continuous thermal iterations. Furthermore, the robust aerogel framework confers exceptional shape-stabilization, reliable electrical isolation (12.47 MΩ), and advanced anti-dripping structural integrity that effectively prevents hazardous flaming liquid runoff and pool fires during aggressive thermal matrix decomposition. When evaluated under a continuous 2C constant-current rapid-charging protocol for 1800 s, the dynamic synergy between accelerated directional heat conduction and large-capacity latent heat buffering successfully shunts intense internal heat flux outward, pinning the battery contact interface temperature at 34.3 °C with a peak regulation efficiency of 69.2%.
Constructing lightweight, outstanding electromagnetic wave absorbers through simple methods represents one of the key strategies to tackle electromagnetic pollution. Here, Fe2O3-modified carbon nanotube/cellulose composite (FCCA) was prepared by freeze-drying with cellulose nanofiber (CNF) as the matrix and the Fe2O3 nanoparticles and carbon nanotube (CNT) as functional fillers. The results indicate that the FCCA composite effectively attenuates electromagnetic waves by extending their propagation path to enhance multi-reflection and scattering, while the introduced CNT impart excellent conductivity, leading to substantial conduction loss. Also, the weakly magnetic Fe2O3 nanoparticles optimizes impedance matching, offers permeability, and enriches the electromagnetic wave dissipation mechanisms. Meanwhile, the abundant heterogeneous interfaces in the FCCA composite generate significant interface polarization, enhancing the polarization relaxation loss of electromagnetic waves. With an Fe2O3 nanoparticle loading of 20% (Fe2O3:CNT=20%), the FCCA-20 composite demonstrated a competitive density of 48.1 mg cm-3. When the thickness was 2 mm, it delivered excellent absorption performance, characterized by a RLmin of -63.5 dB alongside a favorable bandwidth of 5.02 GHz. Furthermore, simulation of the RCS confirmed a maximum reduction of 24.22 dB m2, which indicates effective electromagnetic wave attenuation by the FCCA composite.
Constructing multicomponent heterogeneous interfacial structures and integrating magnetoelectric coupling functions represent the key strategies for developing high-performance electromagnetic wave (EMW) absorbers at a low matching thickness. Silicon carbide nanowires (SiCnws) exhibit excellent dielectric loss capability, yet their traditional synthetic methods rely on long-term high-temperature treatment and suffer from low yield. Single-component SiCnws lack multiple loss mechanisms, which hinders their practical application in EMW absorption. In this study, a stepwise Joule heating method was adopted, and CoNi nanoalloys introduced in situ were used as the growth catalyst for SiCnws, thus successfully synthesizing hierarchical SiCnws@rGO composites. The coexistence of CoNi nanoalloys and rGO introduces both conductive and magnetic loss mechanisms, and the synergy of these multiple loss mechanisms endows the as-synthesized samples with outstanding EMW absorption performance. A minimum reflection loss (RL) of −61.8 dB is achieved at an ultralow matching thickness of only 1.3 mm, with the effective absorption bandwidth (EAB) reaching 4.1 GHz. This work provides an efficient synthetic strategy and theoretical support for the design of high-performance EMW absorbers with low matching thickness.
Herein, we investigate the effect of varying tungsten disulfide (WS2) loadings (0, 0.5, 1.0, and 3.0 wt% within the preceramic polymer) on the multifunctional capabilities of silicon oxycarbide (SiOC) ceramics. Gyroid lattices were produced by digital light processing (DLP) using a polysiloxane-based preceramic resin with varying WS2 loadings, followed by pyrolysis at 800 °C in an inert atmosphere. The addition of nanofillers substantially enhanced electrical conductivity, peaking at 1.0 wt% WS2, despite the relatively low pyrolysis temperature that usually restricts carbon ordering in SiOC. Simultaneously, thermal conductivity declined as WS2 content increased, caused by phonon scattering at the interfaces of the filler and matrix and throughout the designed gyroid framework, allowing for some decoupling of electronic and phononic transport. The 1.0 wt% WS2 concentration exhibited the highest power factor at room temperature and demonstrated an improved thermoelectric response relative to neat SiOC at 400 °C, whereas the 3.0 wt% WS2 showed the maximum ZT at higher temperatures (∼3 × 10−6). The electromechanical sensitivity showed a significant enhancement, with a peak elastic gauge factor (∼121) observed at 1.0 wt% WS2, signifying an ideal percolation network that is very responsive to deformation. The significance of this study lies in the potential of WS2/SiOC as multifunctional materials that combine thermoelectric functionality with mechanical strength and piezoresistive sensing in conditions where conventional materials are not suitable.
Biomass-derived electromagnetic wave (EMW) absorbers with lightweight architectures and multifunctional characteristics are highly desirable for next-generation electromagnetic protection systems. Herein, anisotropic Co nanoparticle-decorated wood-derived carbon monoliths were fabricated through the in-situ growth of ZIF-67 within a natural wood scaffold followed by one-step pyrolysis. Benefiting from the inherited three-dimensional aligned porous architecture, conductive carbon framework, and uniformly dispersed magnetic Co nanoparticles, the resulting composites exhibit excellent electromagnetic attenuation capability. Among all samples, WC/Co-1000 achieved an outstanding minimum reflection loss (RLmin) of −71.8 dB at a thickness of 1.7 mm and a broad effective absorption bandwidth (EAB) of 6.24 GHz. Electromagnetic parameter analysis revealed that the superior absorption performance originated from the synergistic contributions of conduction loss, interfacial polarization, dipolar relaxation, natural resonance, and magnetic loss, together with optimized impedance matching. CST simulations further demonstrated a remarkable radar cross-section reduction of 33.47 dB m2, confirming excellent stealth capability under practical operating conditions. In addition to electromagnetic protection, the WC/Co-1000 exhibited enhanced thermal stability, hydrophobicity, flame resistance, and rapid Joule-heating performance, reaching 153 °C under 5 V. The anisotropic porous structure also contributed to acoustic attenuation and thermal insulation properties. This work provides an effective strategy for constructing lightweight, sustainable, and multifunctional wood-derived composites for applications in electromagnetic protection, stealth technology, aerospace engineering, and advanced communication systems.
