Strong Interfacial Polarization Research Articles

Dimensional Design of Cellulose Aerogels with Schottky Contact for Efficient Microwave Absorption.

Cellulose aerogels, as a novel class of carbon-based materials, exhibit immense potential in the field of microwave absorption (MWA) due to their biocompatibility, low density, unique porous structure, and tunable architecture. However, the development of multi-dimensional components with specialized heterogeneous structures, which are based on cellulose aerogels, remains a significant challenge. This 0D/1D/3D structural configuration facilitates tunable electromagnetic properties and favorable impedance matching. The Schottky contact at the ZnO/Ni interface, in particular, induces a strong interfacial polarization, and the multi-dimensional structural design results in multiple heterointerfaces. Density functional theory (DFT) calculations reveal that the unique Schottky contact induces a Schottky barrier that causes band bending, facilitating the directed migration of electrons at the interface and the formation of an internal electric field, thus significantly accelerating the multipolar relaxation process. As anticipated, the CCMC/ZnO@Ni aerogel exhibits a minimum reflection loss (RLmin) value of -64.0 dB at 13.9 GHz at a thickness of 2.0 mm, and its effective absorption bandwidth (EAB) reaches 4.9 GHz. This work gives valuable guidance and inspiration for the design of multi-dimensional materials that are composed of dimensional gradient structures, which holds great application potential for electromagnetic wave (EMW) attenuation.

Biomass-based MnO2 Composite for Efficient Microwave Absorption Performance: Strong Interfacial Polarization and Electron Transition Effects

In this study, we explored the effectiveness of enhancing microwave absorption capabilities of biomass-derived porous carbon by introducing MnO2 through thermochemical techniques. The results showed that the MnO2-C exhibited higher values in both the real and imaginary parts of the dielectric constant compared to the Control, indicating that the addition of MnO2 significantly enhanced the energy storage and dissipation capabilities. Although the magnetic loss properties of the composite were relatively weak, the increase in conductive and dielectric losses compensated for this aspect. Moreover, the loading of MnO2 optimized the dielectric losses and promoted the reconstruction of charge, enabling MnO2-C to demonstrate superior microwave absorption performance, particularly in the high-frequency range. This is attributed to the multiple polarization mechanisms present in MnO2-C, including interfacial and dipolar polarization, which play a crucial role in enhancing dielectric losses. Additionally, a multilevel porous structure significantly enhanced the scattering and reflection of microwaves, further improving the absorption effectiveness. Consequently, these characteristics contribute to the MnO2-C achieving a minimum reflection loss value of -46.2dB and an expanded effective absorption bandwidth. Overall, the MnO2-C composite, with its optimized electromagnetic properties and complex microstructure, provides valuable insights for the development of new, highly efficient microwave absorption materials.

Synergistically magnetic and dielectric properties of two dimensional Fe3Al@PPy lamellae exhibiting broadband and strong electromagnetic wave absorption

Addressing the issue of low impedance characteristics is essential to improve the electromagnetic wave absorption performance of magnetic materials. Herein, two dimensional Fe3Al@polypyrrole (PPy) lamellae with synergistic magnetic and dielectric properties are fabricated by a mechanical alloying, ordering transformation and polymerization process, which exhibits excellent electromagnetic wave absorption performance. By carefully controlling the thickness of the PPy shell, the optimized Fe3Al@PPy lamellae show a minimum reflection loss of −45.6 dB and an effective absorption bandwidth of 9.1 GHz at a thickness of only 1.5 mm. The conformal growth of Fe3Al@PPy lamellae can induce strong interfacial polarization, dipole polarization, multiple scattering effect and magnetic loss behaviors for the attenuation of electromagnetic waves. This study demonstrates a facile strategy for the development of efficient Fe3Al@PPy composite absorbents showing great potential for practical applications.

Diffusosphere engineering in BNT-based multilayer heterogeneous film capacitors for high performance

Combining layers with high breakdown resistance and high polarization is a promising approach for designing dielectric capacitors with high energy density and efficiency. However, such combinations often accompany strong interfacial polarization, magnification of local electric fields, leading to premature breakdown. This work addresses this issue via controlled formation of diffusospheres. We constructed multilayer heterogeneous films using two Bi0.5Na0.5TiO3 (BNT)-based substances with high breakdown resistance and high polarization properties. Experimental results and finite element simulations demonstrate that the energy storage capacity of these films effectively harnesses the advantages of both phases. Notably, the interface polarization is minimal. Instead, a solid solution-like diffusosphere, formed by the mutual diffusion of ions between the two phases, plays a crucial role. The diffusosphere acts as a transition zone, mitigating charge aggregation at the interfaces and optimizing the relaxor and breakdown characteristics of the capacitor. With six diffusospheres, the multilayer heterogeneous capacitor achieves a recoverable energy storage density of 94 J/cm3, a significant advancement in BNT-based energy storage films. This work proposes and validates the concept of diffusospheres and their role in reducing interfacial polarization in multilayer heterogeneous films, enhancing the understanding of heterogeneous composite structures and advancing the field of dielectric energy storage.

Construction of spherical heterogeneous interface on ZnFe2O4@C composite nanofibers for highly efficient microwave absorption

Enriching the electromagnetic wave loss mechanism and improving the impedance matching are the keys to improve the electromagnetic wave absorption performance of carbon fibers. In this study, beaded ZnFe2O4@C absorbing composite fibers (ZFCF) with synergistic effects of magnetic loss and dielectric loss was prepared by electrospinning and heat treatment. ZnFe2O4 magnetic particles effectively improve the impedance matching and increase the loss mechanism of carbon nanofibers. The optimal ZFCF composite has excellent absorption performance, with a minimum reflection loss of −53.6 dB at 2.64 mm and the widest effective absorption bandwidth of 4.32 GHz. The excellent absorption performance is attributed to significant magnetic losses from eddy currents and magnetic resonance generated by ZnFe2O4, and strong interfacial polarization from the numerous heterogeneous interfaces. Additionally, the one-dimensional carbon nanofibers create a conductive network and structural defects that enhance conductive loss and dipole polarization effects. Moreover, the RCS of ZFCF composite was significantly reduced by −32.85 dBm2. The combination of simulation technology and material design is of great significance for the study of electromagnetic wave absorption mechanism and the rational design of electromagnetic wave absorbing coatings.

Template-sacrificing synthesis of hollow Co@C nanorods for excellent microwave absorption

Metal organic frameworks (MOFs) have been widely used as microwave absorption (MA) materials owing to their varied structures and large specific surface area. However, it is still challenging to endow MOF derivatives with a rational structure to achieve outstanding microwave absorption. In this work, the hollow Co@C nanorods (HCCN) with lots of winding carbon nanotubes on the surface are obtained based on a template-sacrificing method which employs ZnO nanorods as templates and ZIF67 nanoparticles as ornaments. The HCCNs possess large pore size and specific surface area, efficiently improving the impedance matching. The 1D structure, abundant heterointerfaces and defects trigger strong conduction loss, interfacial and dipole polarization, respectively. Therefore, HCCNs exhibits excellent MA properties: the strong reflection loss of −66.8 dB at the thickness of 2.1 mm and the effective absorption bandwidth of 5.68 GHz at 2.5 mm. Radar cross section (RCS) simulation results have confirmed the practicality of HCCNs. This study proposes an inspiration for the structural designing of MOF materials and derivatives to realize amazing MA performance.

In situ fabrication of Fe3C nanoparticles and porous-carbon composites as high-performance electromagnetic wave absorber.

This study successfully utilized a straightforward approach, choosing liquid-liquid phase separation to build a porous structure and synthesize composite absorbers based on polyimide-based porous carbon/Fe3C (PIC/Fe3C-1, PIC/Fe3C-2) nanoparticles and porous carbon/FeCo alloy nanoparticles (PIC/FeCo). The specially designed network structure pore structures contributed multiple reflection, conduction loss and strong interfacial polarization. After characterization, PIC/Fe3C-2 obtained minimum RL of -35.37 dB at 17.04 GHz with 1.55 mm thickness and effective absorption bandwidth of 4.95 GHz with 1.66 mm thickness. Furthermore, PIC/FeCo, with a thickness of 1.63 mm, exhibits the most robust electromagnetic wave loss ability at 15.6 GHz, with a minimum RL of -56.32 dB and an effective absorption bandwidth of 4.88 GHz. Thus, the design strategy presented in this study could serve as a model for synthesizing other high-performance absorbers, effectively mitigating electromagnetic wave-induced pollution.

Constructing Multiphase-Induced Interfacial Polarization to Surpass Defect-Induced Polarization in Multielement Sulfide Absorbers.

The extremely weak heterointerface construction of high-entropy materials (HEM) hinders them being the electromagnetic wave (EMW) absorbers with ideal properties. To address this issue, this study proposes multiphase interfacial engineering and results in a multiphase-induced interfacial polarization loss in multielement sulfides. Through the selection of atoms with diverse reaction activities, the multiphase interfacial components of CuS (1 0 5), Fe0.5 Ni0.5 S2 (2 1 0), and CuFe2 S3 (2 0 0) are constructed to enhance the interfacial polarization loss in multielement Cu-based sulfides. Compared with single-phase high-entropy Zn-based sulfides (ZnFeCoNiCr-S), the multiphase Cu-based sulfides (CuFeCoNiCr-S) possess optimized EMW absorption properties (effective absorption bandwidth (EAB) of 6.70GHz at 2.00mm) due to the existence of specific interface of CuS (1 0 5)/CuFe2 S3 (2 0 0) with proper EM parameters. Furthermore, single-phase ZnFeCoNiCr-S into FeNi2 S4 (3 1 1)/(Zn, Fe)S (1 1 1) heterointerface through 400°C heat-treated is decomposed. The EMW absorption properties are enhanced by strong interfacial polarization (EAB of 4.83GHz at 1.45mm). This work reveals the reasons for the limited EMW absorption properties of high-entropy sulfides and proposes multiphase interface engineering to improve charge accumulation and polarization between specific interfaces, leading to the enhanced EMW absorption properties.

Segmental interactions, interfacial polarization, and gigantic dielectric permittivity in ethylene vinyl acetate copolymer‐carbon nanotube composites

AbstractThis study reports copolymer composition tailored wrapping of carbon nanotubes, leading to a gigantic dielectric permittivity and peculiar nonlinear rheological response in a nonfluoro copolymer/carbon nanotube (CNT) hybrid system. Specifically, we observed a strong interfacial polarization effect in ethylene vinyl acetate (EVAc) copolymer/CNT nanocomposites, resulting in a dielectric permittivity of approximately 4000 at 10 Hz and 450 (dielectric loss <1) at 1 kHz, with only 1% volume fraction of CNTs and 40% vinyl acetate (VAc) content. No such effect was observed in EVAc with 12% VAc. Extensive amplitude oscillatory rheology studies prompted us to propose a novel hook‐wrap‐type mechanism, wherein polar interactions act as hooks and nonpolar segments allow wrapping, depending on the optimal interactions between the CNT and copolymer. Raman spectroscopy, small‐angle x‐ray scattering, and relaxation studies also revealed a significant change in segmental dynamics and mass fractal compactness with a change in the VAc content. This work provides a melt processing‐based scalable route to develop polymer dielectrics while advancing the fundamental understanding of polymer‐CNT interactions and the underlying mechanisms of dielectric behavior in nanocomposites.

Enhancement of dielectric properties in flexible Ti3C2Tx/PVDF composite films

Ti3C2Tx MXene has gained increasing research in high dielectric materials. In this study, Ti3C2Tx nanosheets were incorporated as conductive filler into the PVDF matrix and Ti3C2Tx/PVDF composite films were prepared by an easy solution-casting method. The prepared Ti3C2Tx nanosheets with large aspect ratios were confirmed by XRD, SEM and TEM. The effects of various Ti3C2Tx nanosheets loadings on the morphology, crystallization behaviour and dielectric properties of Ti3C2Tx/PVDF composite films were explored and the mechanism of dielectric properties was explained using an equivalent circuit model. The results showed that a high dielectric permittivity of 155 accompanied by a low dielectric loss of 0.32 at 1 kHz was obtained in the Ti3C2Tx/PVDF composite film with 13 wt% Ti3C2Tx loading. With up to near the percolation limit of 15 wt% Ti3C2Tx loading (fc = 15.9 wt%), the dielectric permittivity increased to 762. The enhanced dielectric properties are mainly caused by the strong interfacial polarization and micro-capacitance effect, as well as good interfacial compatibility between Ti3C2Tx nanosheets and PVDF matrix. This work will provide a promising composite in modern electronic fields.

MOF-derived multicore-shell Fe3O4@Fe@C composite: An ultrastrong electromagnetic wave absorber

Excessive artificial electromagnetic radiation poses significant health risks and disrupts military equipment. To address this, high-performance microwave absorption materials are urgently required. While ferromagnetic materials have excellent absorption but suffer from high density, limited bandwidth, and perishable properties. Carbon materials, especially metal-organic frameworks (MOFs), offer promise due to low density, chemical stability, and high conductivity. In this study, we synthesized a novel multicore-shell Fe3O4@Fe@C composite via solvothermal and in-situ pyrolysis methods. This composite integrated Zn-MOF-derived porous carbon with core-shell Fe3O4@Fe@C, enabling multiple electromagnetic wave routes, strong interfacial polarization, and magnetic-dielectric synergy. It exhibited exceptional electromagnetic wave absorption, with a −59.1 dB reflection loss at 13.36 GHz and a 5.36 GHz effective absorption bandwidth. Our innovative MOF-core-shell approach holds great promise for highly efficient microwave absorbers to mitigate artificial electromagnetic radiation's adverse effects on health and military equipment.

Rational construction of Ni@CBF-x composites derived from bamboo fungus for enhanced microwave absorption with a 10 % filler content

Carbon materials derived from biomass have gained substantial prominence within the domain of microwave absorption (MA). Their eco-friendly attributes, cost-effectiveness, and distinctive morphology have propelled them to the forefront, constituting an effective strategy for the development of sustainable and high-performance microwave absorbing materials (MAMs). Herein, cloud-like porous carbon was derived from bamboo fungus through hydrothermal and carbonization treatment. Subsequently, Ni@carbonized bamboo fungus (Ni@CBF-x) composites were created in situ by introducing magnetic Ni particles. The cloud-like carbon layer derived from bamboo fungus promotes multiple reflections and scattering, enhancing the MA properties of the composites. By adjusting the carbonization temperature, the morphology of Ni particles embedded in the cloud-like porous carbon can be modified, leading to the introduction of numerous heterogeneous interfaces and the construction of 3D conductive networks. Typically, Ni@CBF-800 sample with a filler loading of 10 wt% achieves an impressive minimum reflection loss (RLmin) of –61.2 dB at 10.6 GHz. The effective absorption bandwidth (EAB) of Ni@CBF-1000 sample extends from 6.16 to 11.04 GHz, encompassing 4.88 GHz. Compared to CBF-800 sample, Ni@CBF-1000 sample exhibits a remarkable 171 % increase in EAB, and Ni@CBF-800 exhibits a 50 % increase in RLmin. This exceptional performance can be attributed to four factors, including the strong interfacial polarization induced by the cloud-like porous carbon and Ni particles, the defects created by hydrothermal and carbonization processes, the dipole polarization facilitated by naturally occurring N elements in bamboo fungus, and the magnetic loss caused by magnetic Ni particles. Furthermore, the synergistic coupling of magnetic and dielectric properties serves to optimize the impedance matching characteristics of Ni@CBF-x. These encouraging findings present new avenues for the advancement of magnetic MAMs derived from renewable biomass sources.

Defect Engineering Activates Schottky Heterointerfaces of Graphene/CoSe2 Composites with Ultrathin and Lightweight Design Strategies to Boost Electromagnetic Wave Absorption

AbstractTo tackle the increasingly complex electromagnetic (EM) pollution environment, the application‐oriented electromagnetic wave (EMW) absorption materials with ultra‐thin, light weight and strong tolerance to harsh environment are urgently explored. Although graphene aerogel‐based lightweight EMW absorbers have been developed, thinner thickness and more effective polarization loss strategies are still essential. Based on the theory of EMW transmission, this work innovatively proposes a high attenuation design strategy for obtaining ultra‐thin EMW absorption materials, cobalt selenide (CoSe2) is determined as animportant part of ultra‐thin absorbers. In order to obtain a dielectric parameter range that satisfies the ultra‐thin absorption characteristics and improve the lightweight properties of EMW absorption materials, a composite of CoSe2 modified N‐doped reduced graphene oxide (N‐RGO/CoSe2) is designed. Meanwhile, the controllable introduction of defect engineering into RGO can activate Schottky heterointerfaces of composites to generate a strong interfacial polarization effect, achieving ultra‐thin characteristics while significantly improving the EM loss capability. In addition, infrared thermal images and anti‐icing experiments show that the composite has good corrosion resistance, infrared stealth, and thermal insulation properties. Therefore, this work provides an effective strategy for obtaining thin‐thickness, light‐weight, and high‐performance EMW absorption materials, embodying the advantages of N‐RGO/CoSe2 composites in practical applications.

Inimitable 3D pyrolytic branched hollow architecture with multi-scale conductive network for microwave absorption

To solve the electromagnetic pollution problem, the reasonable structure design and component control of the electromagnetic absorber is prominent. In this work, three-dimensional (3D) pyrolytic branched hollow architecture carbon PBHAC/MoS2 composites were prepared via a hydrothermal and calcination two-step strategy. The narrow-gap nano-size MoS2 acquired after vulcanization and micro-size 3D branched carbon skeleton PBHAC possess intensified conduction losses. Particularly, the presence of potential differences between different phases creates a space charge region at the heterogeneous interface, resulting in strong interfacial polarization. The resulting 3D branched hollow PBHAC/MoS2 composites exhibit optimized impedance matching and multiple loss mechanisms. Finally, the 3D branched hollow carbon PBHAC/MoS2 composites have the best electromagnetic wave (EMW) absorption performance. The minimum reflection loss (RLmin) is –57.8 dB at 1.93 mm and the maximum effective absorption bandwidth (EABmax) is 6.08 GHz at 2 mm, which indicates the excellent EMW absorption performance of the composites. Accordingly, this composite is expected to be a microwave absorber with the characteristics of “thin, light, wide, and strong”.

Self-Assembled MoS2 Cladding for Corrosion Resistant and Frequency-Modulated Electromagnetic Wave Absorption Materials from X-Band to Ku-Band.

Reasonable composition design and controllable structure are effective strategies for harmonic electromagnetic wave (EMW) adsorption of multi-component composites. On this basis, the hybrid MoS2 /CoS2 /VN multilayer structure with the triple heterogeneous interface is prepared by simple stirring hydrothermal, which can satisfy the synergistic interaction between different components and obtain excellent EMW absorption performance. Due to the presence of multiple heterogeneous interfaces, MoS2 /CoS2 /VN composites will produce strong interfacial polarization, while the defects in the sample will become the center of polarization, resulting in dipole polarization. Due to the excellent structural design of MoS2 /CoS2 /VN composite material, MoS2 /CoS2 /VN composite material not only has good conductive loss and polarization loss, but also can maintain excellent stability in simulated seawater, and enhance corrosion resistance. The MoS2 /CoS2 /VN composite with dual functions of corrosion resistant and microwave absorption achieves a minimum reflection loss (RL) of -50.48dB and an effective absorption bandwidth of up to 5.76GHz, covering both the X-band and Ku-band. Finally, this study provides a strong reference for the development of EMW absorption materials based on transition metal nitrides.

In-situ growth of magnetic nanoparticles on honeycomb-like porous carbon nanofibers as lightweight and efficient microwave absorbers

To achieve the goal of both lightweight and strong absorption, tailoring the microstructure and components of microwave absorber had been regarded as a promising method. Herein, in-situ growth of magnetic Ni nanoparticles on honeycomb-like porous carbon nanofibers were prepared by electro-blowing spinning and subsequent high-temperature pyrolysis technique. The honeycomb-like porous structure of carbon nanofibers was formed by the decomposition of pore forming agent PTFE nanoparticles during carbonization process, and the effects of PTFE content on the specific surface area and pore size distribution were systematically studied. Simultaneously, the magnetic Ni nanoparticles were in-situ formed and homogenously dispersed in the fiber skeleton. The obtained fibers were connected into a three-dimensional (3D) interconnected macroscopic network, which could form an electrically conductive network to enhance the conductive loss, and induce multiple reflecting and scattering to consume electromagnetic waves. The honeycomb-like porous structure with large specific surface area could shorten the impedance gap with free space and endow the absorber with light-weight feature. In addition, the in-situ growth magnetic Ni nanoparticles introduced additional magnetic loss, which was also benefit to improve the impedance matching. Moreover, the formed heterojunctions at the interface of magnetic Ni nanoparticles and carbon nanofibers triggered intensive interfacial polarization. Under the synergistic effect of magnetic-dielectric loss, appropriate impedance matching, strong interfacial polarization and multiple reflecting and scattering, the optimal sample of Ni/PCNF-2 presented an excellent microwave absorption performance with the minimum RL of −40.48 dB at 1.5 mm thickness, and the effective absorption bandwidth reached to 4.0 GHz.

Interfacial Polarization Triggered by Covalent‐Bonded MXene and Black Phosphorus for Enhanced Electrochemical Nitrate to Ammonia Conversion

AbstractMXenes have recently emerged as a new class of electrocatalysts for diverse energy conversion reactions, but they are generally considered to be catalytically inert. Herein, a strategy of interfacial polarization is put forward to improve the catalytic activity of MXenes, with the construction of an interfacial structure consisting of black phosphorus (BP) nanoflakes and Nb2C MXene nanosheets for electrochemical nitrate reduction to ammonia as a proof of concept. The experimental and computational results reveal that a strong interfacial polarization is built between BP nanoflakes and Nb2C nanosheets in the prepared BP/Nb2C composite. The polarization of Nb centers by adjacent BP sites gives rise to the formation of positively centered Nb atoms and BP‐polarized Nb atoms, which synergistically catalyze the cleavage of N–O bonds in HNO2* to form NO*. In addition, the stabilization of monatomic *N by the BP/Nb2C composite is also enhanced compared with BP nanoflakes and Nb2C nanosheets. As a result, both the ammonia yield rate and Faraday efficiency of the BP/Nb2C composite are much higher than that of BP nanoflakes and Nb2C nanosheets. Overall, this work shows the great potential for constructing a strong interfacial polarization to improve the catalytic performance of MXenes‐based electrocatalysts.

Multi-mechanism response of molten salt-modified MXene with NiCo2O4 nanosheets for enhanced electromagnetic wave absorption performance

To obtain even superior electromagnetic wave (EMW) absorption materials, research is currently focused on composite absorbers. The aim of this work is to prepare composite absorbers with multiple absorption mechanisms using 2D porous Ti3C2Tx MXene as a substrate. Here, porous Ti3C2Tx MXene nanosheets with a large layer spacing were formed through high-temperature molten salt treatment of layered Ti3C2Tx MXene nanosheets. Then, NiCo2O4 nanosheets were anchored onto the porous Ti3C2Tx MXene nanosheets through heat treatment, forming a heterogeneous structure of porous Ti3C2Tx MXene/NiCo2O4 (P-MXene/NiCo2O4). The heterogeneous interface between Ti3C2Tx MXene and NiCo2O4 nanosheets forms strong interfacial polarization, while NiCo2O4 connects the MXene layer to layer forming a conductive network structure. Furthermore, NiCo2O4 nanosheets suppress the self-stacking of porous Ti3C2Tx MXene nanosheets and improve impedance matching. As a result, P-MXene/NiCo2O4 offers excellent EMW absorption performance with a reflection loss (RL) value of − 64.7 dB at a matching thickness of 4.465 mm. This study provides a new idea for pretreating Ti3C2Tx MXene and constructing efficient composite absorbing materials for electromagnetic waves.

A Water-Free Ionic Covalent Organic Polymer with High Electrorheological Activity and Temperature Stability

Ionic polymers are important electrorheological (ER) materials, whose ER effect originates from ion motion-induced interfacial polarization. However, the first-generation ionic polymer ER material based on traditional polyelectrolyte needs adsorbed water to make ion movement to activate the ER effect. This results in poor temperature and cycling stability. Although the second-generation ionic polymer ER material based on polyethylene oxide-salt complexes and the currently developed poly(ionic liquid) ER material do not require adsorption of water to activate the ER effect due to decreased ion-pair dissociation energy, low glass transition temperature still limits their temperature and cycling stability. Herein, we report an ionic polymer ER material based on ionic covalent organic polymer (iCOP) synthesized via the Menshutkin reaction and ion exchange, which exhibits not only a highly anhydrous ER effect due to lots of hydrophobic fluoric counterion-induced strong interfacial polarization but also excellent temperature stability and cycling stability due to a unique covalent organic framework structure. In particular, its leaking current density and power consumption are far lower than those of the ER system of traditional polyelectrolytes, polyethylene oxide-salt complexes, and poly(ionic liquid)s. These make iCOP possess large potential as a platform to develop next-generation ionic polymer ER material with high performance.

In‐Situ Fabrication of Sustainable‐N‐Doped‐Carbon‐Nanotube‐Encapsulated CoNi Heterogenous Nanocomposites for High‐Efficiency Electromagnetic Wave Absorption

Developing carbon encapsulated magnetic composites with rational design of microstructure for achieving high-performance electromagnetic wave (EMW) absorption in a facile, sustainable, and energy-efficiency approach is highly demanded yet remains challenging. Here, a type of N-doped carbon nanotube (CNT) encapsulated CoNi alloy nanocomposites with diverse heterostructures are synthesized via the facile, sustainable autocatalytic pyrolysis of porous CoNi-layered double hydroxide/melamine. Specifically, the formation mechanism of the encapsulated structure and the effects of heterogenous microstructure and composition on the EMW absorption performance are ascertained. With the presence of melamine, CoNi alloy emerges its autocatalysis effect to generate N-doped CNTs, leading to unique heterostructure and high oxidation stability. The abundant heterogeneous interfaces induce strong interfacial polarization to EMWs and optimize impedance matching characteristic. Combined with the inherent high conductive and magnetic loss capabilities, the nanocomposites accomplish a high-efficiency EMW absorption performance even at a low filling ratio. The minimum reflection loss of -84.0dB at the thickness of 3.2mm and a maximum effective bandwidth of 4.3GHz are obtained, comparable to the best EMW absorbers. Integrated with the facile, controllable, and sustainable preparation approach of the heterogenous nanocomposites, the work shows a great promise of the nanocarbon encapsulation protocol for achieving lightweight, high-performance EMW absorption materials.