High Electromagnetic Interference Shielding Effectiveness Research Articles

Sandwich-Structured Mxene/Waste Polyurethane Foam Composites For Highly Efficient Electromagnetic Interference, Infrared Shielding and Joule Heating.

Electromagnetic interference (EMI) shielding and infrared (IR) stealth materials have attracted increasing attention owing to the rapid development of modern communication and military surveillance technologies. However, to realize excellent EMI shielding and IR stealth performance simultaneously remains a great challenge. Herein, a facile strategy is demonstrated to prepare high-efficiency EMI shielding and IR stealth materials of sandwich-structured MXene-based thin foam composites (M-W-M) via filtration and hot-pressing. In this composite, the conductive Ti3C2Tx MXene/cellulose nanofiber (MXene/CNF) film serves as the outer layer, which reflects electromagnetic waves and reduces the IR emissivity. Meanwhile, the middle layer is composed of a porous waste polyurethane foam (WPUF), which not only improves thermal insulation capacity but also extends electromagnetic wave propagation paths. Owing to the unique sandwich structure of "film-foam-film", the M-W-M composite exhibits a high EMI shielding effectiveness of 83.37dB, and in the meantime extremely low emissivity (22.17%) in the wavelength range of 7-14µm and thermal conductivity (0.19W m-1 K-1), giving rise to impressive IR stealth performance at various surrounding temperatures. Remarkably, the M-W-M composite also shows excellent Joule heating properties, capable of maintaining the IR stealth function during Joule heating.

Regulated orientation and exfoliation of flaky fillers by close packing structures in polymer composites for excellent thermal conduction and EMI shielding

Efficient heat dissipation and electromagnetic interference (EMI) shielding are essential demands on packaging intensively integrated circuits in advanced electronics. Multicompetent polymer composites with thermal conduction and EMI shielding capacity have attracted tremendous interest in the material science community. Herein, we report the preparation of thermally conductive polymer composites with superior EMI shielding effectiveness (SE) by building a 3D interconnected conductive network under close-packing circumstances. The build of the 3D network relies on the coordinated stacking of flaky and spherical fillers, where the asymmetric graphite flakes (FG) are confined in the interstitial regions of the close-packing structures of hollow glass microspheres (HGμS). The “rigid” close-packing structure of HGμS inhibits the in-plane orientation of FG along the flow direction during melt processing and facilitates the exfoliation of FG under external forces producing a conductive network with enhanced interconnectedness. The model system comprised of thermoplastic polyurethane (TPU), FG and HGμS has attained in-plane and through-plane thermal conductivity of 20.54 W m−1 K−1 and 6.55 W m−1 K−1 with 30 vol% FG (while maintaining a low mass density of 1.15 g cm−3, identical to neat TPU). Meanwhile, a high EMI SE of 69 dB has been achieved at a thickness of 1 mm.

Flexible and Robust Core-Shell PANI/PVDF@PANI Nanofiber Membrane for High-Performance Electromagnetic Interference Shielding.

Developing high-performance electromagnetic interference (EMI) shielding materials that are lightweight and flexible and have excellent mechanical properties is an ideal choice for modern integrated electronic devices and microwave protection. Herein, we report the preparation of core-shell polyaniline (PANI)-based nanofiber membranes for EMI shielding through seed polymerization. Electrospinning a PANI solution leads to homogeneously dispersed PANI on the nanofiber surface, with abundant attachment sites for aniline through electrostatic adsorption and hydrogen bonding interaction, allowing PANI to grow on the nanofiber surfaces. This stable core-shell heterostructure provides more interfaces for reflecting and absorbing microwaves. The PANI/PVDF@PANI membranes achieved a shielding efficiency (SE) of 44.7 dB at a thickness of only 1.2 mm, exhibiting an exceptionally high specific EMI shielding effectiveness (SE/t) of 372.5 dB cm-1. Furthermore, the composite membrane exhibits outstanding mechanical stability, durability, air permeability, and moisture permeability, also making it suitable for applications such as EM shielding clothing.

A coding based metasurface absorber with triple circular ring resonator for broadband RCS reduction and high EMI shielding effectiveness

In this paper, a novel coding-based metasurface absorber (CMA) featuring a triple circular ring resonator is introduced for broadband radar cross-section (RCS) reduction and high electromagnetic interference (EMI) shielding effectiveness. The coding element comprises a triple circular ring resonator generating a 1-bit coding scheme (‘0’ and ‘1’ element) with a reflection phase difference of 180° ± 45° across the frequency range of 7.5 GHz–15.5 GHz by employing varying dimensions for the outer circular ring. A most affordable FR-4 substrate with 1.6 mm thickness is used to design the CMA structure. Binary Particle Swarm Optimization (BPSO) algorithm combined with array theory is employed to strategically position unit cells within the subarray. Simulations demonstrate a significant RCS reduction of −10 dBsm across the entire 7.5 GHz–15.5 GHz band. Furthermore, the 2D and 3D scattering patterns observed at 8.26 GHz, 10.56 GHz, and 13.30 GHz serve as additional proof of the remarkable effectiveness of the optimized pattern in reducing bi-static RCS. The optimized CMA structure also exhibits absorption levels exceeding 80 % at different resonance frequency while maintaining high shielding effectiveness. To validate these findings, a prototype of the optimized CMA structure is fabricated, and experimental investigations are conducted. The measured results closely align with the simulated outcomes, with minor discrepancies observed outside the designated frequency band. Based on comprehensive simulation and experimental analyses, the optimized CMA structure emerges as a promising choice for achieving broadband RCS reduction and high EMI shielding effectiveness in practical applications.

Flexible, Reliable, and Lightweight Multiwalled Carbon Nanotube/Polytetrafluoroethylene Membranes with Dual-Nanofibrous Structure for Outstanding EMI Shielding and Multifunctional Applications.

In this study, lightweight, flexible, and environmentally robust dual-nanofibrous membranes made of carbon nanotube (CNT) and polytetrafluoroethylene (PTFE) are fabricated using a novel shear-induced in situ fibrillation method for electromagnetic interference (EMI) shielding. The unique spiderweb-like network, constructed from fine CNTs and PTFE fibrils, integrates the inherent characteristics of these two materials to achieve high conductivity, superhydrophobicity, and extraordinary chemical resistance. The dual-nanofibrous membranes demonstrate a high EMI shielding effectiveness (SE) of 25.7-42.2dB at a thickness range of 100-520µm and the normalized surface-specific SE can reach up to 9931.1 dB·cm2 ·g-1 , while maintaining reliability even under extremely harsh conditions. In addition, distinct electrothermal and photothermal conversion properties can be achieved easily. Under the stimulation of a modest electrical voltage (5V) and light power density (400mW·cm-2 ), the surface temperatures of the CNT/PTFE membranes can reach up to 135.1 and 147.8 °C, respectively. Moreover, the CNT/PTFE membranes exhibit swift, stable, and highly efficient thermal conversion capabilities, endowing them with self-heating and de-icing performance. These versatile, flexible, and breathable membranes, coupled with their efficient and facile fabrication process, showcase tremendous application potential in aerospace, the Internet of Things, and the fabrication of wearable electronic equipment for extreme environments.

From Waste to Value Added Products: Manufacturing High Electromagnetic Interference Shielding Composite from End-of-Life Vehicle (ELV) Waste.

The use of plastics in automobiles is increasing dramatically due to their advantages of low weight and cost-effectiveness. Various products can be manufactured by recycling end-of-life vehicle (ELV) plastic waste, enhancing sustainability within this sector. This study presents the development of an electromagnetic interference (EMI) shield that can be used for protecting electronic devices in vehicles by recycling waste bumpers of ethylene propylene diene monomer (EPDM) rubber from ELVs. EPDM waste was added to a unique combination of 40/60: PP/CaCO3 master batch and conductive nanofiller of carbon nanotubes using an internal melt mixing process. This nanocomposite was highly conductive, with an electrical conductivity of 5.2×10-1S·cm-1 for 5 vol% CNT in a 30 wt% EPDM/70 wt% PP/CaCO3 master batch and showed a high EMI shielding effectiveness of 30.4 dB. An ultra-low percolation threshold was achieved for the nanocomposite at 0.25 vol% CNT. Waste material in the composite improved the yield strain by about 46% and strain at break by 54% in comparison with the same composition without waste. Low cost and light-weight fabricated composite from ELV waste shows high EMI SE for application in electronic vehicles and opens a new path to convert waste to wealth.

Thermoplastic polyurethane foams derived from cellulose nanofibril/carbon nanotube/(Fe/C) aerogels for efficient electromagnetic interference shielding

The electromagnetic interference (EMI) shielding performance of a material can be enhanced by combining carbon and magnetic components to make the material simultaneously conductive and magnetic. In this work, a series of cellulose nanofibril (CNF)/carbon nanotube (CNT)/(Fe/C)/thermoplastic polyurethane (TPU) foams are fabricated by preforming CNF/CNT/(Fe/C) aerogels followed by combing TPU to improve the mechanical property, where Fe/C is derived from Prussian blue (PB, Fe4[Fe(CN)6]3) after pyrolysis. Consequently, the obtained aerogels and foams display electrical conductivity and magnetism. The CNF/CNT/(Fe/C)/TPU foam reaches a high EMI shielding effectiveness value of 42.2 dB at a thickness of 2 mm when the mass ratio of PB and CNT is 5:1 and the pyrolysis temperature is 650 ℃. Furthermore, the CNF/CNT/(Fe/C)/TPU foam exhibits compression resilience and hydrophobicity. This study is expected to provide a feasible strategy to acquire absorption-dominated EMI shielding materials by imparting conductivity, magnetism and porous structures to the material.

Incorporating Loss Factor Modular Design for Full Ku-Band Microwave Attenuation in Double-Layered Graphene Aerogels.

The fabrication of absorption-dominant electromagnetic interference (EMI) shielding materials is a pressing priority to prevent secondary electromagnetic pollution in miniaturized electronic devices and communication systems. Meeting this goal has remained a tough challenge to keep pace with the rapid evolution of electronics due to the complex compositional and structural design and narrow operating bands. This work articulates a sound and simple strategy to precisely modulate the electrical conductivity of reduced graphene oxide (rGO), as the building block in lightweight double-layered rGO-film/rGO-aerogel/polyvinyl-alcohol (PVA) composites, for efficient microwave absorption over the entire Ku-band frequency range. These constructs reasonably comprised a porous absorption structure built from parallel rGO sheets aligned and prepared via freeze casting followed by freeze drying. The electrical conductivity and impedance of this layer were tuned by varying the annealing temperature from 400 to 800 °C, thereby adjusting the degree of reduction and the absorption characteristic. This layer was backed by a highly conductive rGO film reduced at a high temperature of 1000 °C, with a reflectivity of 97.5%. The incorporation of this film ensured high EMI shielding effectiveness of the double-layered structure through the absorption-reflection-reabsorption mechanism, consistent with the predicted values based on calculated loss factors and the input impedance of the structure. Accordingly, at an average EMI shielding effectiveness of 57.59 dB, the reflection shielding effectiveness (SER) and reflectivity (R) of the assembled composites were optimized to be as low as 0.22 dB and 0.049, respectively. This equates to approximately 99.999% shielding (SET) and ∼95% absorptivity (A) of the incident wave. This study opens new avenues for the development of lightweight (with a density as low as 15 mg/cm3) absorption-dominant EMI shielding composite materials with promising EMI shielding efficiency and potential applications in modern electronics.

Construction of strong and superhydrophobic MXene composite films by binary organosilane cross-linking for electromagnetic interference shielding and joule heating

Transition-metal carbide and/or nitride (MXene) with outstanding electrical conductivity and surface chemistry tunability shows great potential for constructing high-performance electromagnetic interference (EMI) shielding materials. Unfortunately, MXene has poor mechanical properties and ambient stability, limiting its practical applications. In this work, strong and superhydrophobic MXene/carboxymethylcellulose sodium (S-MC) composite films were prepared by blade coating followed by binary organosilane modification. Through the joint contributions of hydrogen-bonding interaction, alignment, and organosilane cross-linking of MXene nanosheets, the proposed S-MC films achieved outstanding mechanical properties and EMI shielding performance. For instance, the S-MC composite film containing 90 wt% MXene content demonstrated high specific EMI shielding effectiveness (152 069 dB/cm) and strong tensile strength (181.5 MPa), surpassing those of other reported MXene-based shields. The S-MC films also had excellent Joule heating performance with low applied voltage and quick thermal response. Furthermore, the binary organosilane cross-linking endowed the S-MC films with superhydrophobic properties by inducing rough surface and low surface energy, resulting in stable conductivity and EMI shielding performance in oxidizing and aqueous environments. The developed S-MC films showed enormous potential applications for EMI shielding and Joule heating. Our study offers a novel and scalable strategy to construct strong, stable, and multifunctional MXene-based composites.

Absorption-dominated double-layered electromagnetic interference shielding polymer-based nanocomposites: Optimal design and manufacturing

Double-layered electromagnetic interference (EMI) shielding composites having a gradient structure to achieve an efficient EMI shielding effectiveness (SE) with a low electromagnetic wave reflectivity (R) would be highly desired for engineering applications to control secondary electromagnetic pollution. However, it is still challenging to optimize their performance and structure efficiently. In this work, theoretical calculations were conducted on the prepared double-layer shielding polymer composite material using an improved normalized input impedance (NII) method to verify and optimize the structural composition and R-value of the composite material. The R-value of the composite can be calculated iteratively based on the conductivity and electromagnetic parameters of each material layer, and in this way the optimal structural composition to achieve the lowest R-value can be well predicted. Thus, the optimal structural composition to achieve the lowest R value can be well predicted from the theoretical calculation. Suggested by the theoretical calculation, the double-layered waterborne polyacrylate/polydopamine modified reduced graphene oxide/Cu@Ag (WPA/rGO@PDA/Cu@Ag) composite has achieved broadband low-reflectivity. The R values of the resultant WPA/rGO@PDA-20 wt%/Cu@Ag-1.448 mm composite are <0.5 over 8.3–12.4 GHz, implying its broadband low reflection performance while possessing a high EMI shielding effectiveness beyond 44.3 dB. The modified NII method is promising for advancing the practical production and engineering application of multilayered absorption-dominated EMI shielding composites.

Electromagnetic interference shielding of graphene/PMMA composites depending on growth temperature of CVD-graphene

The research on graphene, driven by its exceptional mechanical, electrical, and thermal properties, has garnered significant attention, making it a promising multi-functional material for electronics. In this study, we investigated the effect of the synthesis temperature on the crystalline quality and the electromagnetic interference (EMI) shielding performance of graphene. We performed graphene synthesis on Cu foil at different temperatures (from 900° to 1050°C) and subsequently analyzed the samples using Raman spectroscopy. The results showed that the crystalline quality of graphene increased with increasing synthesis temperature. We then fabricated a 100-layer graphene/poly(methyl methacrylate) (PMMA) composite (GPC) and evaluated its electrical, mechanical properties, and EMI shielding effectiveness (SE). Our findings revealed the GPC with high crystalline graphene had a higher electrical conductivity and tensile strength than the GPC with defective graphene. In addition, the GPC with high crystalline graphene had a higher EMI SE, with a total SE of 14.16 dB, which is 140 % higher than that value for a defective graphene structure.

Hyperelastic, Robust, Fire‐Safe Multifunctional MXene Aerogels with Unprecedented Electromagnetic Interference Shielding Efficiency

AbstractMXene aerogels have shown great potential for many important functional applications, in particular electromagnetic interference (EMI) shielding. However, it has been a grand challenge to create mechanically hyperelastic, air‐stable, and durable MXene aerogels for enabling effective EMI protection at low concentrations due to the difficulties in achieving tailorable porous structures, excellent mechanical elasticity, and desired antioxidation capabilities of MXene in air. Here, a facile strategy for fabricating MXene composite aerogels by co‐assembling MXene and cellulose nanofibers during freeze‐drying followed by surface encapsulation with fire‐retardant thermoplastic polyurethane (TPU) is reported. Because of the maximum utilization of pore structures of MXene, and conductive loss enhanced by multiple internal reflections, as‐prepared aerogel with 3.14 wt% of MXene exhibits an exceptionally high EMI shielding effectiveness of 93.5 dB, and an ultra‐high MXene utilization efficiency of 2977.71 dB g g−1, tripling the values in previous works. Owing to the presence of multiple hydrogen bonding and the TPU elastomer, the aerogel exhibits a hyperelastic feature with additional strength, excellent stability, superior durability, and high fire safety. This study provides a facile strategy for creating multifunctional aerogels with great potential for applications in EMI protection, wearable devices, thermal management, pressure sensing, and intelligent fire monitoring.

3D printed epoxy composite microsandwich with high strength, toughness, and EMI shielding performances

Materials with exceptional mechanical and electromagnetic interference (EMI) shielding properties are urgently needed due to the growing demand for multifunctional protection layers in aviation and new energy vehicles. Herein, we fabricate an epoxy-based composite microsandwich composing of solid and lattice layers via 3D printing. The rationally assembled layered architecture together with high manufacturing accuracy give the microsandwich high strength, toughness, and fracture toughness, exhibiting 92%, 140%, and 18.5% improvement compared to its solid counterpart, respectively. The solid layers bear most of the loadings, while the cellular lattice layers can prevent quick crack propagation, resulting in simultaneously high strength and toughness. Besides, the synergetic effect of the solid and lattice layers also effectively promotes the multiple reflection of the incident electromagnetic waves, giving rise to a high EMI shielding effectiveness. The above findings might offer insights into the achievement of highly tunable multifunctional properties for epoxy-based composites through properly controlled architectures.

Flexible N-doped carbon nanofiber containing Nb2O5 nanoparticle and its polydimethylsiloxane composite for electromagnetic interference shielding

The miniaturization of electronic devices and systems has led to increasingly sophisticated electronic circuits, resulting in electromagnetic interference (EMI) that can substantially influence performance of electronic devices and wireless communications. To address this issue, researchers have extensively explored various strategies including application of EMI shielding materials. Here, we use Nb2O5 nanoparticles incorporated N-doped carbon nanofibers (Nb2O5–CNF) for EMI shielding applications in wide frequency range (8.2 GHz–26.5 GHz). Nb2O5–CNF was prepared through electrospinning, followed by carbonization. A 50 wt% loading of Nb2O5 (Nb2O5–CNF-50) exhibited high EMI shielding effectiveness of 67 dB with a thickness of 0.08 mm, where, more than 80% of shielding is through absorption mechanism. Ease of handling of Nb2O5–CNF could be improved by making flexible PDMS composites of Nb2O5–CNF. The PDMS composites exhibited similar EMI shielding behavior in the frequency range 8.2–26.5 GHz. Nb2O5–CNF and their PDMS composites can open up new possibilities towards large scale production of lightweight, flexible, and easy-to-integrate materials to shield workspaces, surroundings, and complex electronic circuits against unwanted EM radiations.

Electrostatic induced self-assembled MXene/EPOSS for high-performance electromagnetic interference shielding materials

It is still a challenge to prepare flexible electromagnetic interference (EMI) shielding materials based on Ti3C2Tx MXene through a facial and scalable method. In this study, epoxied octamethyl-cyclotetrasiloxane (EPOSS) was self-assembled with Ti3C2Tx to construct EMI shielding composites via facial spraying coating. Because the EPOSS decreased the surface free energy of Ti3C2Tx in the acid-base component, the Ti3C2Tx/EPOSS suspension was able to be sprayed on carboxylated polybutadiene (CPB) uniformly. Molecular dynamics (MD) simulations were explored to demonstrate the interaction energy between EPOSS and CPB with different –COOH contents. The prepared EMI shielding composite has high abrasion resistance and good bending durability because EPOSS reinforced the interface interaction between Ti3C2Tx and CPB through covalent bonds. Based on a pre-stretching spray method, the prepared composite has high surface roughness, leading to a high specific EMI shielding effectiveness of 1800 dB cm2 g−1 at a low Ti3C2Tx loading of 8.5 wt%. Additionally, the physically protective effect of Si–O–Si cages in EPOSS provided good flame retardancy. Therefore, the proposed EPOSS-assisted Ti3C2Tx spraying strategy could prepare EMI shielding materials with high effectiveness, excellent abrasion resistance, and good flame retardancy, which has a broad prospect for the application of high-power, portable, and wearable flexible electronic devices.

Conductivity-Controlled Polyvinylidene Fluoride Nanofiber Stack for Absorption-Dominant Electromagnetic Interference Shielding Materials.

This work presents a novel method for achieving lightweight electromagnetic interference (EMI) shielding materials with high EMI shielding effectiveness (SE) through absorption-dominant mechanisms, utilizing only organic polymer nanofibers (NFs). Instead of incorporating high-density fillers, the approach involves adjusting the concentrations of iron chloride in the NFs and subsequent vapor phase polymerization (VPP) to control the polymerization density of poly(3,4-ethylenedioxythiophene) (PEDOT) on the surface of polyvinylidene fluoride (PVDF) NFs. This process results in NF layers with varying conductivity, creating a conductivity gradient structure. The conductivity gradient structure of the NF layers significantly enhances absorptivity by reducing impedance mismatches between the shielding material and the surrounding air, as well as between different interlayers. This reduction in impedance mismatches allows for efficient dissipation of absorbed electromagnetic (EM) waves within the highly conductive NF layer. This improved absorptivity is also attributed to the attenuation of EM wave energy through multiple reflections and scattering within the NF pores. Moreover, the gradient structure of the NF layers promotes interfacial polarization, further contributing to the effective absorption of electromagnetic waves. As a result, a high absolute EMI SE (SSEt) of 12,390 dB·cm2 g-1 with low reflectivity (0.32) was achieved without compromising the lightweight and flexible properties.

Heterogeneous Waterborne Polyurethane Composite with Alternating Electromagnetic Layers for Absorption-Dominated Electromagnetic Interference Shielding.

Flexible waterborne polyurethane (WPU) electromagnetic interference (EMI) composites of heterogeneous alternating multilayer structure with conductive gradient were fabricated through the layer-by-layer stacking and hot-pressing methods. Combining the synergetic electromagnetic loss and interface polarization loss formed by the selective distribution of metallized chopped polyimide fiber (PI@Ni/Cu/Ni), reduced graphene oxide (rGO), and magnetic Fe3O4 fillers, as well as multilevel electromagnetic wave propagation paths, the penetrating microwaves would undergo a particular "absorption-reflection-reabsorption" process in the composite. The asymmetric multilayer WPU composite with an absorption-dominated shielding feature exhibits a high EMI shielding effectiveness (SE) of 53.90 dB and an A value of 0.56. Moreover, the multilayer WPU composite maintains excellent integrity through repeating bending, long-time soaking, and burning tests. This work provides a viable strategy for the design of absorption-dominated EMI shielding material with controllable and stable performance that is befitting for next-generation advanced electronic products.

MXenes (Ti3C2Tx) incorporated polyimide nanohybrid composite films

In this study, polyimide (PI)/MXene hybrid composite films as electromagnetic interference (EMI) shielding materials were fabricated using MXene (Ti3C2Tx) as a filler. The PI/MXene nanohybrid composite films were fabricated by casting an aqueous solution containing water-soluble poly (amic acid) ammonium salt (PAS) and MXene colloid, followed by thermal imidization. PI/MXene hybrid composite films with different contents (1.36 wt. % ∼ 20 wt. %) were prepared. The PI/MXene hybrid composite films showed high EMI shielding effectiveness up to 159 dB/mm as well as low moisture contents, controlled dielectric constants, improved thermal stability, and low coefficients of thermal expansion.

Scalable Fabrication of Nacre-Structured Graphene/Polytetrafluoroethylene Films for Outstanding EMI Shielding Under Extreme Environment.

In this work, inspired by the great advantage of the unique "brick-mortar" layered structure as electromagnetic interference (EMI) shielding materials, a multifunctional flexible graphene nanosheets (GNS)/polytetrafluoroethylene (PTFE) composite film with excellent EMI shielding effects, impressive Joule heating performance, and light-to-heat conversion efficiency is fabricated based on the self-emulsifying process of PTFE. Both PTFE microspheres and nanofibers are employed together for the first time as "sand and cement" to build unique nacre-structured EMI shielding materials. Such configuration can obviously enhance the adhesion of composites and improve their mechanical property for the application under extreme environment. Moreover, the simple and effective repetitive roll pressing method can be used for the scalable production in industrialization. The GNS/PTFE composite film shows a high EMI shielding effectiveness (SE) of 50.85dB. Furthermore, it has a high thermal conductivity of 16.54W (m K)-1 , good flexibility, and recyclable properties. The excellent fire-resistant and hydrophobic properties of GNS/PTFE film also ensure its reliability and safety in practical application. In conclusion, the GNS/PTFE film demonstrates the potential for industrial manufacturing, and outstanding EMI shielding performance with high stability and durability, which has a broad application prospect for electronic devices in practical extreme outdoor environments.

Highly aligned reduced graphene oxide in alumina composites for strengthening, toughening, and electromagnetic interference shielding

Engineering ceramics with high strength, toughness and electromagnetic interference (EMI) shielding effectiveness (SE) are highly desirable as electromagnetic protecting material in harsh environment. Herein, we show that both excellent mechanical and EMI shielding performance can be realized in alumina composites embedded with highly aligned reduced graphene oxide (RGO), which are readily prepared via sintering of core-shell structured RGO@Al2O3 nanoplates with pressure. Compared to monolithic Al2O3, the highly aligned RGO/Al2O3 composites show simultaneously improved strength and toughness up to ∼26.1% and ∼60.2%, respectively. The steeply rising R-curve behavior proves the better crack tolerance in the highly aligned structure with respect to randomly oriented one. Moreover, the RGO/Al2O3 composites also exhibit a high specific EMI SE reaching ∼34 dB/mm in K band, due to the reflection and highly enhanced absorption after percolation in the out-of-plane direction. These findings provide a novel strategy of designing mechanically reliable engineering ceramic for EMI shielding.