Microstructure Design and Dimensional Engineering of Nanomaterials for Electromagnetic Wave Absorption and Thermal Insulation.

Multifunctional materials integrated with electromagnetic wave absorption (EWA), thermal insulation, and lightweight properties are urgently indispensable for the flourishing advancement of space technology, which can simultaneously prevent electromagnetic detection and resist aerodynamic heating. To achieve excellent synergistic EWA and thermal insulation performance, the elaborate regulate the microstructure and dimension of nanomaterials has emerged as a captivating research direction. However, comprehending the structure-property relationships between microstructure, electromagnetic response, and thermal insulation mechanisms remains a significant challenge.

Ultraflexible Ultrathin 3D/1D Hierarchical Interpenetrating Ni-MOF/CNT Buckypaper Composites: Microstructures and Microwave Absorption Properties.

Metal-organic frameworks (MOFs) have attracted attention due to their designable structures. However, recently reported MOF microwave-absorbing materials (MAMs) are dominated by powders. It remains a challenge to design MOF/carbon nanotube (CNT) composite structures that combine the mechanical properties of self-supporting flexibility with excellent microwave absorption.

A Pyrophosphate Bifunctional Cathode with Inductive Effect for High-Voltage and Self-Charging Zinc Ion Battery.

With the growing demand for new energy storage devices, rechargeable aqueous zinc ion batteries (ZIBs) have attracted widespread attention due to their low cost and high safety. Among the cathode materials for ZIBs, polyanionic-based cathode materials with high voltage, high stability, and low cost have great potential. In this paper, tetragonal NaVOPO was prepared using a simple sol-gel method.

Robust TiCT MXene foam modified with natural antioxidants for long-term effective electromagnetic interference shielding.

MXenes have been proven to be outstanding lossy phase of advanced electromagnetic interference (EMI) shielding materials. However, their poor tolerance to oxygen and water results in fast degradation of the pristine two-dimensional (2D) nanostructure and fading of the functional performance. Herein, in this research, natural antioxidants (e.

Introduction of Nanoscale SiN to Improve the Dielectric Thermal Stability of a SiN/P(VDF-HFP) Composite Film.

In order to improve the dielectric thermal stability of polyvinylidene fluoride (PVDF)-based film, nano silicon nitride (SiN) was introduced, and hence the energy storage performance was improved. The introduction of nano SiN fillers will induce a phase transition of P(VDF-HFP) from polar β to nonpolar α, which leads to the improved energy storage property. As such, the discharging energy density of SiN/P(VDF-HFP) composite films increased with the amount of doped SiN.

Amorphous/Nanocrystalline, Lightweight, Wave-Transparent Boron Nitride Nanobelt Aerogel for Thermal Insulation.

At present, the new generation of aircraft is developing in the direction of high speed, long endurance, high mobility, and repeatability. Some studies have shown that the surface temperature of the radome can reach even 1800 °C as the flight speed of the aircraft increases. However, the antenna inside the radome cannot serve at this temperature.

Construction of Hollow Carbon Nanofibers with Graphene Nanorods as Nano-Antennas for Lower-Frequency Microwave Absorption.

Electromagnetic (EM) wave absorbers at a lower-frequency region (2-8 GHz) require higher attenuation ability to achieve efficient absorption. However, the impedance match condition and attenuation ability are usually inversely related. Herein, one-dimensional hollow carbon nanofibers with graphene nanorods are prepared based on coaxial electrospinning technology.

Wide-temperature-range multispectral camouflage enabled by orientation-gradient co-optimized microwave blackbody metastructure coupled with conformal MXene coating.

Cloaking against electromagnetic detection is a well-researched topic; yet achieving multispectral camouflage over a wide temperature range remains challenging. Herein, an orientation-gradient co-optimized graded Gyroid-shellular (GGS) SiOC-based metastructure with a conformal MXene coating (M@SiOC) is proposed to achieve wide-temperature-range microwave/infrared/visible-light-compatible camouflage. Firstly, the combination of coordinate transformation and genetic algorithm endows the GGS architecture with optimal orientation and gradient, allowing superior microwave blackbody-like behavior.

Formation and Evolution of Micro/Nano Periodic Ripples on 2205 Stainless Steel Machined by Femtosecond Laser.

The preparation of micro/nano periodic surface structures using femtosecond laser machining technology has been the academic frontier and hotspot in recent years. The formation and evolution of micro/nano periodic ripples were investigated on 2205 stainless steel machined by femtosecond laser. Using single spot irradiation with fixed laser fluences and various pulse numbers, typical ripples, including nano HSFLs (‖), nano LSFLs (⟂), nano HSFLs (⟂) and micro grooves (‖), were generated one after another in one test.

Nature-Inspired 3D Spiral Grass Structured Graphene Quantum Dots/MXene Nanohybrids with Exceptional Photothermal-Driven Pseudo-Capacitance Improvement.

Solar-thermal conversion is considered as a green and simple means to improve the performance of energy storage materials, but often limited by the intrinsic photothermal properties of materials and crude structure design. Herein, inspired by the unique light trapping effect of wide leaf spiral grass during photosynthesis, a biomimetic structural photothermal energy storage system is developed, to further promote the solar thermal-driven pseudo capacitance improvement. In this system, three-dimensional printed tortional Kelvin cell arrays structure with interesting light trapping property functions as "spiral leaf blades" to improve the efficiency of light absorption, while graphene quantum dots/MXene nanohybrids with wide photothermal response range and strong electrochemical activity serve as "chloroplast" for photothermal conversion and energy storage.

Tunable hydrogen enhancement of Ce doped CdS with different Poisson's ratio support.

In this article, a 3D photocatalytic support with different Poisson's ratio was used for the first time to control the photocatalytic production rate of hydrogen. It was created by a stereo-lithography method, and the support with the most negative Poisson's ratio got the best result. The Poisson's ratio of the 3D structure influences the rate of hydrogen production, and it is important for the photocatalyst supports to be porous for light to penetrate into them.

Micro/Nano Periodic Surface Structures and Performance of Stainless Steel Machined Using Femtosecond Lasers.

The machining of micro/nano periodic surface structures using a femtosecond laser has been an academic frontier and hotspot in recent years. With an ultrahigh laser fluence and an ultrashort pulse duration, femtosecond laser machining shows unique advantages in material processing. It can process almost any material and can greatly improve the processing accuracy with a minimum machining size and heat-affected zone.

Non-Destruction Evaluation Method for Long-Term Oxidation Behavior of SiC/SiC Composites with Different Preforms in Wet Oxygen.

The implementation of SiC fiber reinforced SiC/SiC composites to aero-engine hot components has attracted wide attention, due to their many excellent properties. Along these lines, in order to predict the oxidation behavior of the material in extreme environments and to explore the effect of different preforms on the oxidative behavior of the composites, four SiC/SiC composites, with different preforms, were oxidized under environmental conditions of pressure of 12 kPa HO:8 kPa O:80 kPa Ar, at 1400 °C temperature. Moreover, the morphology and defect distribution of the samples were characterized by carrying out scanning electron microscopy, and micro-computed X-ray tomography measurements.

Ti C T /MoS Self-Rolling Rod-Based Foam Boosts Interfacial Polarization for Electromagnetic Wave Absorption.

Heterogeneous interface design to boost interfacial polarization has become a feasible way to realize high electromagnetic wave absorbing (EMA) performance of dielectric materials. However, interfacial polarization in simple structures such as particles, rods, and flakes is weak and usually plays a secondary role. In order to enhance the interfacial polarization and simultaneously reduce the electronic conductivity to avoid reflection of electromagnetic wave, a more rational geometric structure for dielectric materials is desired.

Bi selectively doped SrTiO nanosheets enhance photocatalytic CO reduction under visible light.

Converting CO into chemical energy by using solar energy is an environmental strategy to achieve carbon neutrality. In this paper, two dimensionality (2D) SrTiO nanosheets with oxygen vacancies were synthesized successfully. Oxygen vacancies will generate defect levels in the band structure of SrTiO.

3D Printed Electrochromic Supercapacitors with Ultrahigh Mechanical Strength and Energy Density.

With the accelerating update of advanced electronic gadgets, a great deal of attention is being paid today to the function integration and intelligent design of electronic devices. Herein, a novel kind of multitasking 3D oxygen-deficient WO  ∙ 2H O/Ag/ceramic microscaffolds, possessing simultaneous giant energy density, ultrahigh mechanical strength, and reversible electrochromic performance is proposed, and fabricated by a 3D printing technique. The ceramic microscaffolds ensure outstanding mechanical strength and stability, the topology optimized porous lattice structure provides developed surface area for coloration as well as abundant easily accessible channels for rapid ion transportation, and the bifunctional oxygen-defective pseudomaterials enable the large areal capacity and impressive electrochromic performance.

Rational design of n-BiTiO@p-BiOI core-shell heterojunction for boosting photocatalytic NO removal.

Bismuth titanate (BiTiO) with unique sillenite structure has been shown to be an excellent photocatalyst for environmental remediation. However, the narrow light-responsive range and rapid recombination of photoinduced electrons-holes limit the photocatalytic performance of BiTiO. To overcome the limitations, a practical and feasibleway is to fabricate heterojunctions by combining BiTiO with suitable photocatalysts.

Formation of Ultra-High Temperature Ceramic Hollow Microspheres as Promising Lightweight Thermal Insulation Materials via a Molten Salt-Assisted Template Method.

Ultra-high temperature ceramics (UHTCs) have become a vital candidate material system for thermal protection systems in aerospace applications. However, high thermal conductivity and high density are the main obstacles to the application of UHTCs. It is a promising solution to prepare porous UHTCs using UHTC hollow microspheres (HMs) as a pore-forming agent.

3D-Printed Topological MoS/MoSe Heterostructures for Macroscale Superlubricity.

Superlubricity is a fascinating phenomenon which attracts people to continuously expand ultralow friction and wear from microscale to macroscale. Despite the impressive advances in this field, it is still limited to specific materials and extreme operating conditions. Introducing a heterostructure with intrinsic lattice mismatch into delicate topologies mimicked from nature provides a promising alternative toward macroscopic superlubricity.

Infinite Approaching Superlubricity by Three-Dimensional Printed Structures.

The rapid development of three-dimensional (3D) printing technology opens great opportunities for the design of various multiscale lubrication structures. 3D printing allows high customization of arbitrary complex structures and rapid prototyping of objects, which provides an avenue to achieve effective lubrication. Current experimental observations on superlubricity are limited to atomically smooth clean surfaces, extreme operating conditions, and nano- or microscales.

Adjusting the Morphology and Properties of SiC Nanowires by Catalyst Control.

We report on the growth of SiC nanowires on a single crystal Si substrate by pyrolysis of polycarbosilane and using two catalyst (AlO and Ni) films with different thickness (2, 4, and 6 nm). The catalyst films were deposited on the Si substrate, and the SiC nanowires were grown according to two mechanisms, i.e.

Morphology Design of Co-electrospinning MnO-VN/C Nanofibers for Enhancing the Microwave Absorption Performances.

To enhance microwave loss abilities, constructing composites with one-dimensional (1D) structure is an excellent scheme. In this work, a high-efficiency microwave absorber of MnO nanograins decorated vanadium nitride/carbon nanofibers (MnO-VN/C NFs) was successfully prepared for the first time via co-electrospinning technology and subsequent nitriding treatment. Studying in detail the specific relationship between nitriding time and the morphology of the as-prepared NFs, the precipitations of MnO nanoparticles with tailored structures were attached on the surface of VN/C NFs to optimize their electromagnetic parameters.

Preparation and Performance of SiN Hollow Microspheres by the Template Method and Carbothermal Reduction Nitridation.

Silicon nitride (SiN) hollow microspheres with smaller particle size and narrower distribution can be used to prepare closed-cell ceramics as the pore-forming agent to improve heat insulation performance and wave-transparent performance of porous SiN ceramics. In this work, SiN hollow microspheres with a diameter of about 1 μm and a wall thickness of approximately 150 nm were prepared by using the template method combined with the carbothermal reduction nitridation method. The optimum preparation temperature of the SiN hollow microspheres is 1450 °C.

Ultralight Cellular Foam from Cellulose Nanofiber/Carbon Nanotube Self-Assemblies for Ultrabroad-Band Microwave Absorption.

Microwave absorption materials (MAMs) with lightweight density and ultrabroad-band microwave absorption performance are urgently needed in advanced MAMs, which are still a big challenge and have been rarely achieved. Here, a new wide bandwidth absorption model was designed, which fuses the electromagnetic resonance loss ability of a periodic porous structure in the low-frequency range and the dielectric loss ability of dielectric materials in the high-frequency range. Based on this model, a lightweight porous cellulose nanofiber (CNF)/carbon nanotube (CNT) foam consisting of a cellular vertical porous architecture with the macropore diameters between 30 and 90 μm and a nanoporous architecture at a scale of 1.

Lightweight TiCT MXene/Poly(vinyl alcohol) Composite Foams for Electromagnetic Wave Shielding with Absorption-Dominated Feature.

Lightweight absorption-dominated electromagnetic interference (EMI) shielding materials are more attractive than conventional reflection-dominated counterparts because they minimize the twice pollution of the reflected electromagnetic (EM) wave. Here, porous TiCT MXene/poly(vinyl alcohol) composite foams constructed by few-layered TiCT (f-TiCT ) MXene and poly(vinyl alcohol) (PVA) are fabricated via a facile freeze-drying method. As superior EMI shielding materials, their calculated specific shielding effectiveness reaches up to 5136 dB cm g with an ultralow filler content of only 0.