Materials Horizons最新文献

Electrolyte optimization is recognized as a critical strategy for enhancing both the long-term cycling stability and safety performance of lithium-ion batteries. Modified electrolytes must possess the following critical properties, including suppressed decomposition reactions, reduced viscosity at low temperatures, and enhanced ionic transport capabilities, while ensuring compatibility with high-voltage cathodes and optimizing the formation of both solid electrolyte interphases (SEI) and cathode electrolyte interphases (CEI). With the inherent limitations of traditional carbonate-based systems, emerging solvents including fluorinated, ether, sulfone and siloxane-based solvents demonstrate significant potential due to their intrinsic safety and wide temperature adaptability. Fluorinated solvents reduce the formation of lithium dendrites to improve safety, and ether-based solvents have low viscosity and excellent low-temperature performance for extreme environments, while sulfone and siloxane-based solvents exhibit excellent thermal stability and interfacial compatibility to extend cell longevity, respectively. Through synergistic molecular design and experimental optimization, such advanced electrolyte systems not only underpin the development of high-energy-density lithium-ion batteries but also establish the basis for breakthroughs in energy storage technology, especially in electric vehicles, renewable energy systems and operation under extreme conditions. Future research should prioritize innovations in high-performance electrolytes that will accelerate the progress of the global energy transition and contribute to carbon neutrality objectives.

Conductive hydrogels are promising materials for advanced applications in artificial muscles, biomimetic soft robotics, and wearable electronics. However, the simultaneous realization of rapid reversible actuation, superior mechanical robustness, and high-resolution multimodal sensing remains a formidable challenge. Herein, we present a multifunctional hydrogel based on thermos-responsive poly(N-isopropylacrylamide) (PNIPAM), reinforced via acrylamide (AM) copolymerization and polyvinyl alcohol (PVA) network integration, which synergistically enhance mechanical strength and toughness. The incorporation of MXene nanosheets endows the hydrogel with stable, repeatable, and ultrasensitive piezoresistive sensing performance. Moreover, the hydrogel exhibits excellent photothermal actuation under near-infrared (NIR) irradiation, enabling remote, light-actuation deformation coupled with real-time self-sensing. To enrich its sensing modalities, a piezoelectric composite layer composed of poly(vinylidene fluoride-trifluoroethylene) and barium titanate [P(VDF-TrFE)/BTO] is integrated, allowing simultaneous detection of strain amplitude, movement direction, and velocity. As a proof of concept, a biomimetic octopus predation system was constructed, showcasing the potential of this integrated actuator-sensor platform for intelligent soft robotic systems.

Wireless technology advances exacerbate electromagnetic interference challenges, fueling the demand for microwave absorption (MA) materials with broadband compatibility and adaptive tunability. This work proposes a dual-layer intelligent broadband MA composite. The upper and lower layers exhibit complementary microwave loss characteristics across the frequency spectrum. Synergistically, this ensures high-efficiency MA that seamlessly covers the entire 2-18 GHz band. Specifically, the dual-layer structure utilizes carbonyl iron powder (CIP)/boron nitride (BN) and FeSiAl/BN/vanadium dioxide (VO₂) composite powders, prepared via plasma ball milling, for the upper-layer and lower-layer absorbers, respectively. The BN coating modulates the dielectric properties of the composite powders. As a result, the upper layer, featuring a lower characteristic impedance, primarily attenuates X/Ku-band microwaves, while the lower layer, with a higher characteristic impedance, is designed to absorb S/C-band microwaves. Strong magnetic loss from CIP in the X/Ku band and FeSiAl in the S/C band further enhances layer-specific MA within their target frequency ranges. Ultimately, this structure achieved an ultra-wide effective absorption bandwidth (EAB) of up to 13.49 GHz at a thickness of 3.70 mm. Compared with the application of a single magnetic absorber, it demonstrated a 48% enhancement in EAB. Additionally, the VO₂ enables dynamic Ku-band MA modulation through insulator-to-metal transition, yielding a maximum tunable EAB range (ΔEAB) of 8.35 GHz. A dynamic poly(urethane urea) matrix enables the composite to achieve adhesive-free layer assembly through self-healing. Thus, this composite is promising for applications in 5G/6G telecommunications, multi-band radar and health-monitoring flexible devices.

The electromechanical properties of piezoelectric materials are influenced significantly by the defect chemistry, which is determined by the solid-solubility and charge-compensation mechanisms. In the present work, the effects of Sn⁴⁺ doping of lead-free (Ba_0.85Ca_0.15)([Ti_0.92-xSn_x]Zr_0.08)O₃ (x = 0.00-0.10) ceramics on these parameters and the resultant electromechanical properties and energy-storage efficiencies are reported. The complex nature of the solid solubility mechanisms as a function of dopant content is elucidated through comprehensive analyses of the structures, microstructures, and surface chemistry. The corresponding charge compensation mechanisms are determined by correlating these characterization data with corresponding defect equilibria, which then provide the basis for the interpretation of the mechanisms governing the electromechanical properties and energy-storage efficiencies. The combined data for the surface Ti oxidation state (XPS) and bulk unit cell volumes (XRD) for the three observed polymorphs (orthorhombic Pmm2, tetragonal P4mm, and cubic Pm3̄m) reveal interstitial solid solubility at low (0.00 ≤ x ≤ 0.04) and high (0.08 ≤ x ≤ 0.10) Sn⁴⁺ doping levels, with intermediate (0.04 < x < 0.08) Sn⁴⁺ doping levels exhibiting mixed interstitial-substitutional solid solubility. The trends in the electromechanical properties correlate directly with the solid solubility mechanisms, with two resultant inflections at x = 0.04 (maximal defect concentration) and x = 0.08 (minimal defect concentration). These mechanisms significantly influence the electromechanical properties, where maxima occur for polarization at x = 0.04, bipolar strain at x = 0.08, and energy storage efficiency at x = 0.10. The latter is notable because this parameter reaches >95% across the wide temperature range of 25°-130 °C.

Sustainable, autonomous, adaptive, and next generation flexible electronic systems inside Internet of Things (IoT) and wearable devices have resulted in innovative advancements in energy harvesting technologies. Despite the existence of numerous energy harvesting technologies, triboelectric nanogenerators (TENGs) have emerged as a potential option for powering smart and compact electronic devices. This study focuses on the fabrication of high-performance TENGs composed of a composite layer with SrBi₄Ti₄O₁₅ (SBTO) embedded in polydimethylsiloxane (PDMS) and a biocompatible, natural pectin polymer layer. Utilizing the synergistic dielectric enhancement of SBTO, a lead-free Aurivillius-type perovskite, and the charge-accumulative characteristics of pectin, the TENG achieved exceptional electrical performance, with an output voltage reaching 375.7 V, an output current of 20.8 μA and a power density of 12.5 W m^-2 under optimal conditions. An optimal filler concentration of 7 wt% and an operating frequency of 5 Hz produced maximum charge transfer efficiency. The engineered devices exhibited exceptional mechanical durability (>10 000 cycles), environmental stability (>30 days), and humidity resistance (45-90% R.H) when encapsulated. Moreover, incorporating TENGs into autonomous fire alarm systems substantiates their real-time sensing and notification capabilities via the integration of Wi-Fi and Bluetooth modules that function without batteries. The developed system delivers prompt, location-specific alerts via human-initiated activation, even during emergencies. This work demonstrates the scalable design of flexible TENGs, offering a unique alternative for autonomous fire detection in off-grid or high-risk environments.

Drug-encapsulated scaffolds are crucial to treat challenging bone defects, but the approach for loading drugs into scaffolds is limited. Despite microspheres as carriers that improve drug efficacy and the therapeutic window, the traditional "first preparation - then encapsulation" in drug-microsphere encapsulated scaffolds remains complicated and time-consuming. Herein, we present a facile approach for fabricating drug-microsphere in site encapsulated bone-repair scaffolds (CHP@Drug), in which a solid-liquid interaction triggered by vortex oscillation can be leveraged to realize in site preparation and simultaneous encapsulation of drug-loaded microspheres, rapidly and uniformly. Owing to the induced collision, homogenized and reinforced shear stress from the solid-liquid interaction, CHP@Drug endowed a sustained drug release and an interconnected porous structure. As a proof of concept, CHP@Drugs, were loaded with three drugs respectively, demonstrating significantly enhanced healing of critical-sized, infected, and osteoporotic bone defects in vivo. This study offers a facile and universal way to load drugs into tissue-repair scaffolds, with in-clinic potential.

The extensive utilization of synthetic detergents presents a substantial threat to the global environment. Inspired by traditional practices in Asia-such as using rice-washing water for cleaning-this study develops a green, non-toxic, and surfactant-free detergent. The innovative detergent was fabricated using natural collagen extracted from delimed bovine hide trimmings as the core component, requiring no chemical modification. It forms in situ Pickering emulsions on contaminated surfaces, effectively encapsulating and removing oil stains. Interfacial desorption energy measurements indicate that the collagen detergent adsorbs irreversibly at the oil-water interface (approximately 2.2 × 10⁷K_BT). The collagen detergent achieves a comparable cleaning efficiency of up to 90% on both human skin and various material surfaces, in comparison with commercial products. More importantly, it is non-irritating to the eyes and skin and exhibits no toxicity toward cells, seeds, lettuce seedlings, and zebrafish. By combining high detergency with exceptional biocompatibility and environmental safety, this approach offers a compelling alternative to conventional surfactants. Remarkably, the detergent is produced solely from delimed bovine split trimmings, demonstrating the potential of collagen valorization for next-generation sustainable cleaning agents that align with ecological preservation and public health priorities.

As the annual volume of data production exceeds tens of zettabytes, there is increasing interest in developing non-volatile materials for next-generation memory technologies. Among them, HfO₂-based fluorite-structured ferroelectrics have emerged as leading candidates due to their ability to maintain ferroelectric properties even at thicknesses below 10 nm and their compatibility with conventional complementary metal-oxide-semiconductor (CMOS) processes. However, the inherently large depolarisation field induced by the ultra-thin film nature makes it challenging to achieve the over 10-year data retention required for practical memory applications. In this study, we identify that retention degradation originates from the tail region of the polarisation switching distribution and demonstrate that Lorentz-tail engineering can substantially enhance retention performance. Accelerated retention tests show that the engineered ferroelectric HZO retains over 93% of its polarisation after a projected 10 years, thus contributing to the advancement of HfO₂-based ferroelectrics for memory device applications.

In this work, we demonstrate for the first time tunable upconversion luminescence in three primary colors using a single excitation wavelength of 980 nm, via altering the excitation intensity. A core/shell/shell nanocrystal of about 50 nm diameter was synthesized using a design strategy with 2% Er³⁺ and 98% Yb³⁺ in the core, and the outer shell is made of NaYF₄:Yb³⁺,Tm³⁺ (with 2% Tm³⁺ and 18% Yb³⁺), separated by an inert intermediate shell. This rationally designed architecture enables green, red, and blue light emissions by modulating the excitation power density, leveraging the photon-order-dependent upconversion process. As the power density of the 980 nm continuous-wave (CW) laser increases, the emission color shifts systematically from green to red and ultimately to blue, corresponding to the involvement of 2-photon, 3-photon, and 4-photon processes, respectively. Chromaticity coordinate shifts on the CIE diagram validated this dynamic color modulation, demonstrating precise control over emission pathways. The findings offer a simplified yet highly versatile excitation setup for full RGB tunability, paving the way for advancements in photonics and enabling possibilities in high-resolution color display and biomedical applications.

Flame-retardant coatings provide effective fire protection for various substrates, yet developing eco-friendly alternatives that combine strong adhesion, high-efficiency flame retardancy, and excellent thermal insulation remains a formidable challenge. Inspired by the nesting behavior of birds, a fully biomass-based fire-retardant coating without traditional flame-retardant elements was constructed through a green multiple-groups synergy strategy for "one stone for multiple birds" that concurrently incorporates nanostructuring, strong adhesion, thermal insulation, and universal flame retardancy. In this design, gallic acid (GA) self-assembles into nanofibrous-like supramolecular aggregates through π-π stacking, mimicking structural "twigs". Meanwhile, chitosan acts as a cohesive binder, replicating the adhesive function of "saliva". The resulting coating exhibits a bird nest-like interpenetrating structure with nanopores (<250 nm), which reduces the thermal conductivity of rigid polyurethane foam (RPUF) to 24.85 mW (m K)^-1 from 28.57 mW (m K)^-1. The synergy of decarboxylation/carbonization and radical scavenging imparts self-intumescent barrier properties and universal flame retardancy to diverse materials (fabric, RPUF, paper, wood), yielding a limiting oxygen index of 25-30%, and smoke and toxic gas suppression. This work presents a biomimetic strategy for sustainable, high-performance flame-retardant coatings with broad applicability.