Electromagnetic Interference Shielding Research Articles

A review of recent advances in MXenes/polymer‐based electromagnetic interference shielding materials

AbstractThe booming development of mobile devices has remarkably improved the lives of people, but it also leads to severe electromagnetic radiation problems. Therefore, it has become significantly important to develop electromagnetic interference (EMI) shielding materials for electromagnetic protection. In recent years, MXenes have attracted much attention in the field of EMI shielding, owing to outstanding electrical conductivity, high specific surface area and hydrophilicity. Firstly, this review introduces EMI shielding mechanism and categorization of EMI shielding materials. Subsequently, the research progress of MXenes/polymer‐based EMI shielding materials is reviewed in detail, especially for preparation methods of MXenes/polymer‐based EMI shielding blocks. Finally, the key scientific problems in MXenes/polymer‐based EMI shielding materials are proposed, and their development trend are prospected.Highlights The EMI shielding mechanism and categorization of EMI shielding materials is presented. The latest research progress of MXenes/polymer‐based EMI shielding materials is reviewed. Scientific problems for MXenes/polymer‐based EMI shielding materials are proposed. Development trend of MXenes/polymer‐based EMI shielding materials is prospected.

Electromagnetic Interference Shielding Properties of Highly Flexible Poly(styrene-co-butyl acrylate)/PEDOT:PSS Films Fabricated by Latex Technology.

As the use of stretchable electronic devices increases, the importance of flexible electromagnetic interference (EMI) shielding films is emerging. In this study, a highly flexible shielding film was fabricated using poly(styrene-co-butyl acrylate) (p(St-co-BA)) latex as a matrix and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as a conductive filler, and then the mechanical properties and EMI shielding performance of the film were examined. Styrene and butyl acrylate were copolymerized to lower the high glass transition temperature and increase the ductility of brittle polystyrene. The latex blending technique was used to produce a shielding film in which the aqueous filler dispersion was uniformly dispersed in the emulsion polymerized resin. To determine the phase change in the copolymer matrix with temperature, the storage modulus was measured, and a time-temperature superposition master curve was constructed. The drying temperature of water-based copolymer resin suitable for film fabrication was set based on this curve. The glass transition temperature and flexibility of the blends were determined by evaluating the thermomechanical analysis and tensile tests. The EMI shielding effectiveness (SE) of the films was analyzed at frequencies from 50 MHz to 1.5 GHz, covering the VHF and UHF ranges. As the filler content increased, the SE of the blend film increased, but the elongation increased until a certain content and then decreased. The optimal content of PEDOT:PSS that satisfied both the ductility and shielding performance of the film was found to be 10 wt%. In this case, the elongation at break reached 300%, and the SE of a 1.6 mm thick film was about 35 dB. The film developed in this study can be used as an EMI shielding material that requires high flexibility.

Enhancing structural analysis and electromagnetic shielding in carbon foam composites with applications in concrete integrating XGBoost machine learning, carbon nanotubes, and montmorillonite

Electromagnetic shielding in carbon foam composites involves using the natural conductivity of carbon foam to block or absorb electromagnetic fields. These composites protect sensitive electronic devices from electromagnetic interference (EMI), which can disrupt or damage their operation. The inclusion of XGBoost machine learning analyzes and optimizes the material compositions for electromagnetic interference shielding. By integrating Carbon Nanotubes (CNTs) and Montmorillonite (MMT) into samples of carbon foam, this research aims to identify the electromagnetic shielding effectiveness (SE), electrical conductivity, and dielectric permittivity at different frequencies of carbon foam composites. This analysis will facilitate the development of enhanced composite materials tailored for effective EMI shielding in concrete environments, particularly in structures housing sensitive electronic equipment. The novelty of this study lies in the dual integration of carbon nanotubes and montmorillonite into carbon foam composites, uniquely exploring their synergistic effects on both mechanical and electrical properties. The study employs XGBoost machine learning to optimize the material compositions for enhanced electromagnetic interference shielding. This study probes the dual integration of CNTs and montmorillonite into carbon foam composites, evaluating their synergistic impact on mechanical and electromagnetic properties. Incorporating 1 %, 3 %, and 5 % of these additives into carbon foams, substantial improvements were recorded in compressive, tensile, and flexural strengths, peaking with a 5 % MMT enhancement that nearly doubled the compressive strength from 3.96 MPa to 9.44 MPa. Concurrently, these composites displayed enhanced EMI SE, with detailed electrical characterizations at varying frequencies. Employing XGBoost machine learning, optimal material compositions were derived for EMI shielding, presenting advancements for industrial applications requiring robust structural and electrical performance.

Multifunctional wood-derived cellulose/Ti3C2Tx composite films enhanced by densification strategy for electromagnetic shielding, Joule/solar heating, and thermal camouflage

In the era of increasing reliance on electronic devices, the development of flexible smart composite films that offer multifunctional capabilities such as electromagnetic shielding, sensing, infrared stealth, and autonomous heating is becoming increasingly significant. In this study, we fabricated polydopamine-modified cellulose scaffold/MXene composite films (PCM) using a densification strategy, resulting in films with a thickness of only 33 μm, outstanding tensile strength of 235.28 MPa, and excellent electromagnetic shielding effectiveness of 44.6 dB. The PCM also demonstrates remarkable electrothermal performance, reaching temperatures of up to 610 °C at 5 V, and exhibits excellent photo-thermal conversion performance, along with good cycling stability and tunability. Additionally, the PCM’s low infrared emissivity provides it with exceptional infrared stealth capabilities, effectively concealing a high surface temperature ranging from 250 °C to 25 °C. The PCM’s ability to detect human body movement and light-driven actuation for bionic motions underscores its flexibility and utility as a sensor. Therefore, this efficient and versatile approach provides a promising method for synthesizing multifunctional MXene-based composite films, achieving satisfactory mechanical properties, high electromagnetic interference shielding, and effective thermal management for wearable smart devices and military applications.

Enhancement of electromagnetic interference shielding properties of hemp fiber sandwiched carbon fiber composites using electroless NiP coating

The present study aimed to improve the electromagnetic interference (EMI) shielding effectiveness (SE) of woven hemp fiber (HF) sandwiched carbon fiber (CF) epoxy composites using electroless Nickel-phosphorus coating. Furthermore, the phase composition, functional groups, microstructure, elemental composition, mapping and electrical conductivity of the raw fiber and coated fiber were analyzed in detail. Three different composite samples were prepared and their EMI SE was studied using a key sight 9374A vector network analyzer with 8–12 GHz frequency band (X-band frequency). The EMI SET of the raw HF sandwiched CF composite (S1) was observed as 61.17 dB. But, the addition of 1-layer coated HF between CF (S2) has increased the EMI SET from 61.17 to 83.16 dB. The 2 layer coated HF between CF (S3) had exhibited 92.77 dB which is 51.66 % higher than the S1 composite.

Fabrics Modified with Ag Nanowire/Cellulose Nanofibril Composites for High Conductivity, Electromagnetic Interference Shielding, Ultraviolet Protection, and Thermal Insulation

Fabrics Modified with Ag Nanowire/Cellulose Nanofibril Composites for High Conductivity, Electromagnetic Interference Shielding, Ultraviolet Protection, and Thermal Insulation

Improvement of thermal, mechanical, and electromagnetic interference shielding properties of polyethylene nanocomposites by introducing non‐covalently modified carbon nanotube and reactive polyethylene copolymer

AbstractWe herein report the enhancement of thermal, electrical, electromagnetic interference (EMI) shielding, and mechanical performance of polyethylene (PE) nanocomposites by the introduction of non‐covalently modified multi‐walled carbon nanotube (MWCNT) and ethylene‐glycidyl methacrylate (EGMA) copolymer. For this purpose, benzylacetic acid‐functionalized MWCNT (BA‐M) is prepared by ball milling, and it is melt‐mixed with EGMA to prepare a masterbatch. The masterbatch is then melt‐compounded with neat PE to manufacture a series of PE/EGMA/BA‐M nanocomposites with 0.5–5 wt% MWCNTs. Electron microscopic and spectroscopic analyses confirm the successful fabrication of non‐covalently functionalized BA‐M, the uniform dispersity of MWCNTs in the PE matrix, and the chemical reactions between the carboxylic acid groups of BA‐M and the epoxy group of EGMA in the nanocomposites. Scanning calorimetric data reveals that BA‐M acts as an efficient nucleating agent for the crystallization of PE. The excellent dispersity and robust interfacial bonding of BA‐M in the PE matrix result in improved electrical and EMI shielding properties in PE/EGMA/BA‐M nanocomposites. Furthermore, the tensile strength, initial modulus, and impact strength of the nanocomposites gradually rise as the BA‐M content increases. Thus, the PE/EGMA/BA‐M nanocomposite containing 5 wt% MWCNT achieves excellent performance of EMI shielding effectiveness of ~14.7 dB/mm, tensile strength of ~34.5 MPa, initial modulus of ~295.7 MPa, and impact strength of ~539.9 J/m, which represent enhancements of ~265%, ~40%, ~82%, and ~452%, respectively, compared to pristine PE.Highlights Non‐covalently modified MWCNT (BA‐M) was prepared by facile ball milling. PE nanocomposites with BA‐M and EGMA were prepared by masterbatch melt‐mixing. Excellent dispersity and interfacial bonding of MWCNT in the PE matrix were attained. Tensile strength and initial modulus of the nanocomposites were highly improved. EMI shielding effectiveness of the nanocomposite with 5 wt% MWCNT was ~14.7 dB/mm.

Multifunctional polyimide/boron nitride nanosheet/Ti3C2Tx MXene composite film with three-dimensional conductive network for integrated thermal conductive, electromagnetic interference shielding, and Joule heating performances

With the demand for further miniaturization and higher frequency operation of electronic devices, polymer films with high thermal conductivity and electromagnetic interference (EMI) shielding effectiveness (SE) are urgently required. Herein, polyimide (PI)/boron nitride nanosheets (BNNS) aerogels with oriented porous structure are fabricated by unidirectional-freezing and freeze-drying methods. Subsequently, hierarchical PI/BNNS/Ti3C2Tx composite films with consecutively electrically and thermally conductive networks are successfully prepared via a unidirectional PI/BNNS aerogels-assisted immersion and hot-pressing strategy. Owing to the three-dimensional conductive dual networks of BNNS and Ti3C2Tx, the composite film exhibits excellent thermal conductivity with the maximum in-plane value of 4.73 W/(m·K), increased by 456 % compared to pure PI film. Moreover, the conductive network of Ti3C2Tx is conducive to the excellent EMI shielding performance, endowing the PI/BNNS/Ti3C2Tx composite film with an outstanding EMI SE value of 49.2 dB at 8.2 GHz with a low MXene content of 6 wt% and thickness of 300 μm. Furthermore, the composite film shows the superior Joule heating performance with fast thermal response and sufficient reliability. Therefore, the resulting composite film exhibits excellent thermal conductive, EMI shielding and Joule heating performance, which enables the potential application of multifunctional composites for thermal management and EMI shielding.

Lightweight thermoplastic polyurethane/multi-wall carbon nanotube foams with a continuous gradient cell structure for electromagnetic interference shielding

With the rapid development of portable microelectronic devices, materials with tunable electromagnetic shielding (EMI) performance and comfort of use have become urgently necessary. A lightweight, conductive thermoplastic polyurethane/multi-walled carbon nanotube (TPU/MWCNT) composite foam with a continuous gradient cell structure has been developed to impede electromagnetic wave reflection induced by excessive impedance mismatch. The continuous gradient distribution of cell structure and conductivity provides the TPU/MWCNT composite foams with distinct shielding effects of electromagnetic waves in both front and back gradient directions. The maximum front absorption coefficient (A) reached 0.93, which is higher than any foam with a uniform cell size within the cell size range of the gradient composite foams. At the same time, the gradient composite foams possess the characteristics of lightweight, high elasticity, and extensibility. The weight was decreased by 67.27–85.45 %, the elastic recovery ratio of compression reached 95 %, and the toughness was also excellent. Numerical simulation of the gradient foam model was conducted using CST Microwave Studio to uncover the gradient asymptotic dissipation mechanisms. The lightweight and stretchable continuous gradient foams show great promises for the next-generation portable electronic devices that generate no radiation pollution.

Absorption‐Dominant Electromagnetic Interference (EMI) Shielding across Multiple mmWave Bands Using Conductive Patterned Magnetic Composite and Double‐Walled Carbon Nanotube Film

AbstractThe revolution of millimeter‐wave (mmWave) technologies is prompting a need for absorption‐dominant EMI shielding materials. While conventional shielding materials struggle in the mmWave spectrum due to their reflective nature, this study introduces a novel EMI shielding film with ultralow reflection (<0.05 dB or 1.5%), ultrahigh absorption (>70 dB or 98.5%), and superior shielding (>70 dB or 99.99999%) across triple mmWave frequency bands with a thickness of 400 µm. By integrating a magnetic composite layer (MCL), a conductive patterned grid (CPG), and a double‐walled carbon nanotube film (DWCNTF), specific resonant frequencies of electromagnetic waves are transmitted into the film with minimized reflection, and trapped and dissipated between the CPG and the DWCNTF. The design factors for resonant frequencies, such as the CPG geometry and the MCL refractive index, are systematically investigated based on electromagnetic wave propagation theories. This innovative approach presents a promising solution for effective mmWave EMI shielding materials, with implications for mobile communication, radar systems, and wireless gigabit communication.

Nickel-Fe3O4@Graphene coated lightweight carbonized wood for efficient electromagnetic interference shielding

The miniaturization and integration of electronic equipment promote electromagnetic effect radiation pollution more and more serious. The lightweight, renewable electromagnetic interference (EMI) shielding materials is urgently needed. This study developed a high temperature carbonization, Fe3O4@Graphene impregnation, and electroless Ni technique to construct a carbonized wood composite with strong EMI shielding performance using sustainable natural wood as the raw material. The Fe3O4@Graphene is distributed throughout the carbonized wood to provide the conductivity and magnetism of the reinforced composite material, and provide more interfaces to increase the dielectric loss and magnetic loss, thereby exhibiting excellent EMI shielding performance. The results show that at low thickness (2 mm) and ultra-low density (0.284 g/cm3), the CWN-7 composite exhibits excellent EMI shielding effectiveness of up to 84.2 dB in the whole X-band (8.2–12.4 GHz). At the same time, it has extraordinary compressive strength and good thermal insulation performance. This study offers a different method for creating composite multifunctional electromagnetic shields out of carbonized green wood.

Smart windows with adjustable electromagnetic interference shielding using hydrogel technology

Thermochromic smart windows with adjustable electromagnetic interference (EMI) shielding capability are integral elements in modernized buildings, especially in military applications, due to their energy-saving benefits and ability to mitigate electromagnetic pollution. However, its application is limited by the relatively poor light transmission of conductive substances and the high demand for light transmission of thermochromic smart windows. Maintaining the thermochromic performance of smart windows while adjusting EMI shielding effectiveness (SE) poses a significant challenge. Here, we propose a straightforward approach to create a smart EMI shielding material with adaptable properties, including light transmission, shape, and EMI SE. This method involves a layer-by-layer polymerisation process followed by solvent substitution. The resulting hydrogel exhibits tunable optical properties, making it suitable for use as a smart window that responds to external conditions and offers local tunability. Noteworthy characteristics include high light transmittance (80.87 %), ultra-fast response time (16 s), multiple shape adjustments, adjustable EMI SE ranging from 0 to 27.64 dB, and strong adhesion, among other features. These findings suggest that the obtained hydrogels have significant potential to provide a substantial advantage in developing next-generation soft and intelligent smart EMI shielding windows.

Large-area (50 cm × 50 cm) optically transparent electromagnetic interference (EMI) shielding of ZTO/Ag/ZTO: an analytical/numerical and experimental study of optoelectrical and EMI shielding properties

Transparent conducting oxides (TCOs), exhibiting both high optical transparency and low electrical resistivity, are commonly employed in optoelectronic devices. However, acquiring a balance between these optical and electrical properties in a uniform way over large areas has been a pending challenge, which is essential to achieving optically transparent electromagnetic interference (EMI) shielding surfaces. In this study, we propose and demonstrate a stratified thin film structure consisting of zinc-doped tin oxide (Zn2SnO4, ZTO) as TCO along with a metal layer of silver (Ag) deposited on a large area of 50 cm × 50 cm polycarbonate (PC) substrate enabled by a scanning magnetron sputtering gun. We achieved high EMI shielding of 99.9% at the optical transparency of 68% in the visible spectrum by engineering the stratified architecture of ZTO/Ag/ZTO. The Ag layer of 18 nm in thickness with a sheet resistance of 10 Ω/sq yields shielding effectiveness (SE) of 27 dB in a wide frequency range of 2–20 GHz. The bottom and top ZTO layers, 20 and 40 nm thick, respectively, provide the lowest optical loss of 13% across 400–700 nm. The structure’s EMI shielding, optical and structural performances were systematically characterized through a free-space focused-beam system, UV–Vis spectrophotometer, ellipsometry, focused ion-beam cross-sectional sampling and imaging, transmission electron microscopy, atomic force microscopy and secondary ion mass spectroscopy. EMI shielding and optical performances were validated by CST Microwave Studio and the transfer matrix method, respectively. These findings indicate that the proposed multi-layer architecture holds great promise for large-area EMI shielding and other optoelectronic applications.

An ultralight all‐fiber‐structure sponge with thermal and electromagnetic integrated insulation property

AbstractThe integration of thermal and electromagnetic interference (EMI) insulation is of great significance for fields such as aerospace that face extreme environments. The challenge lies in ensuring that the protective layer is lightweight while simultaneously possessing the ability to suppress heat conduction, heat convection, thermal radiation, and electromagnetic radiation. To address these challenges, we propose a novel ultralight all‐fiber‐structure composite sponge, yttria‐stabilized zirconia/polyvinyl butyral‐supported silver (YAP) nanofiber sponge, with ultralight mass (∼65 mg/cm3), exceptionally low thermal conductivity (21 mW/m K at 25°C, and 329 mW/m K at 500°C), and remarkable EMI shielding effectiveness (∼62.6 dB). Moreover, benefiting from its all‐fiber‐structure, the YAP nanofiber sponge can endure 100 cycles of compression up to 50% of its original volume while retaining its mechanical properties with minimal degradation. These characteristics render YAP nanofiber sponge an ideal material for integrated thermal and EMI insulation, offering a promising solution to the rigorous demands of extreme environment protection such as space exploration.

Determination of Photothermal and EMI Shielding Efficiency of Graphene-Silver Nanoparticle Composites Prepared under Low-Dose Gamma Irradiation.

Silver nanoparticles (Ag NPs) have been produced by low-dose (1-20 kGy) gamma irradiation of silver nitrate in the presence of graphene-based material (graphene oxide or electrochemically exfoliated graphene). The large surface area of those graphene-based materials combined with the presence of oxygen-containing functional groups on the surface provided successful nucleation and growth of Ag nanoparticles, which resulted in a uniformly covered graphene surface. The obtained Ag nanoparticles were spherical with a predominant size distribution of 10-50 nm for graphene oxide and 10-100 nm for electrochemically exfoliated graphene. The photothermal efficiency measurement showed a temperature increase upon exposure to a 532 nm laser for all samples and the highest photothermal efficiency was measured for the graphene oxide/Ag NP sample prepared at 5 kGy. Electromagnetic interference (EMI) shielding efficiency measurements showed poor shielding for the composites prepared with graphene oxide. On the other hand, all composites prepared with electrochemically exfoliated graphene showed EMI shielding to some extent, and the best performance was measured for the samples prepared at 5 and 20 kGy doses.

Multifunctional Integrated Organic–Inorganic-Metal Hybrid Aerogel for Excellent Thermal Insulation and Electromagnetic Shielding Performance

HighlightsThe homogeneous hybridization of organic–inorganic-metal elements in 3D aerogel was achieved by an expeditious method.The aerogel tightly integrates excellent thermal insulation (49.6 mW m−1 K−1), ablative resistance, mechanical strength, and superhydrophobic properties.The ablated carbon aerogel combines notable electromagnetic interference shielding properties (31.6 dB) and load-carrying properties (272.8 kN·m kg−1).

Advanced Polymer Composite with Graphene Content for Emi Shielding

One of the increasingly common unexpected outcomes of the extensive usage of electronic devices and systems is electromagnetic interference (EMI). The need for efficient fillers and shielding materials to manage electromagnetic interference (EMI) and associated issues is rising. Adding more filler typically means greater production costs, poor dispersion, and unintended agglomeration, which makes polymer composites harder to work with and mechanically weak. Therefore, it is highly desired to design a strong composite with conductive filler content that nonetheless performs well as an EMI shield. Therefore, using a graphene substrate and dispersion of conducting polymers such as polyacetylene and MWCNT fillers, a hybrid polymer composite based on polyetherimide is proposed in this research. Next, the enhancement of EMI shielding efficiency is examined. The design of the graphene substrate was completed with a coating based on nano filler, and the blending methods of the polymer matrix and the reinforcing filler materials are explored. ANSYS-HFSS software is then used to assess the shield's efficacy among others, and the results demonstrated improved performance. Therefore, by putting the suggested design into practice, high-performance EMI shielding materials can be created by combining various shield fillers. As a result, the composites' mechanical, electrical, and EMI shielding qualities will all improve.

Sustainable graphene production for solution-processed microsupercapacitors and multipurpose flexible electronics

The growing demand for portable and wearable electronics, Internet of Things microdevices, and wireless sensor networks has led to the development of miniaturized energy storage devices, such as microsupercapacitors (mSCs). With excellent electrical conductivity and high surface area in a layered structure, graphene materials are ideal for mSCs, but current manufacturing methods still hinder their widespread integration. Here, we propose a sustainable approach for the rapid and eco-friendly production of few-layer graphene flakes based on the exfoliation of graphite in water by a combination of high-shear mixing and a high-pressure airless spray. An all-carbon composite paste with high electrical conductivity and tunable viscosity was designed to fabricate planar, interdigitated mSCs on polyethylene terephthalate (PET). The flexible, metal-free mSCs achieved a Coulombic efficiency close to 100%, with areal and volumetric capacitances of 6.16 mF cm−2 and 2.46 F cm−3, respectively. The maximum energy density exceeds 200 μWh cm−3 with 91.5% capacitance retention after 10000 galvanostatic chargedischarge cycles. The mSCs retain the same performance when subjected to a wide bending range and can be easily modularized to adjust the voltage and capacitance outputs. Finally, high-performance coatings for electromagnetic interference shielding and wearable strain sensors are also fabricated to demonstrate the multipurpose applicability of the graphene-based paste.

Strong and flexible MXene-based nanocomposite films for atomic oxygen resistance and electromagnetic interference shielding

MXene has garnered considerable attention as a promising candidate for multifunctional artificial materials, owing to its exceptional mechanical performance and superior electric conductivity. However, macroscopically layered films assembled by MXene nanosheets are usually accompanied by serious degradation of mechanical properties. Moreover, there is a notable paucity of investigations on MXene in low Earth orbit (LEO) environment. Inspired by the layered structure of nacre, we applied polyurethane (PU) as an interfacial crosslinking agent to improve the mechanical properties of MXene films. The optimized MXene/PU (MP) nanocomposite film exhibited a tensile strength of 298.02 MPa and a toughness of 13.81 MJ m−3, surpassing those of the pure MXene film by 260 % and 1300 %, respectively. The atomic oxygen (AO) erosion yield of MP was approximately one order of magnitude lower than that of commercial Kapton films, which was attributed to the shielding effect of MXene against AO attacks. Remarkably, the MP nanocomposite film demonstrated exceptional retention of tensile strength under various extreme conditions including AO irradiation, cryogenic-high temperature, cyclic thermal shock and hot water. Contributed by multi-layer structural design and high conductivity, the MP exhibited a high electromagnetic interference shielding effectiveness (EMI SE) of 48 dB and a specific SE divided by thickness (SSE/t) of 13,479 dB cm2 g−1 at the thickness of 20 μm. Consequently, the nacre-like MP nanocomposite film with exceptional mechanical properties and high-level functional performance holds substantial promise as a multifunctional space material for LEO environments.

Multistage microcellular waterborne polyurethane composite with optionally low-reflection behavior for ultra-efficient electromagnetic interference shielding

Electromagnetic interference (EMI) shielding materials with superior shielding efficiency and low-reflection properties hold promising potential for utilization across electronic components, precision instruments, and fifth-generation communication equipment. In this study, multistage microcellular waterborne polyurethane (WPU) composites were constructed via gradient induction, layer-by-layer casting, and supercritical carbon dioxide foaming. The gradient-structured WPU/iron-cobalt loaded reduced graphene oxide (FeCo@rGO) foam serves as an impedance-matched absorption layer, while the highly conductive WPU/silver loaded glass microspheres (Ag@GM) layer is employed as a reflection layer. Thanks to the incorporation of an asymmetric structure, as well as the introduction of gradient and porous configurations, the composite foam demonstrates excellent conductivity, outstanding EMI SE (74.9 dB), and minimal reflection characteristics (35.28 %) in 8.2–12.4 GHz, implying that more than 99.99999 % of electromagnetic (EM) waves were blocked and only 35.28 % were reflected to the external environment. Interestingly, the reflectivity of the composite foam is reduced to 0.41 % at 10.88 GHz due to the resonance for incident and reflected EM waves. Beyond that, the composite foam is characterized by low density (0.47 g/cm3) and great stability of EMI shielding properties. This work offers a viable approach for crafting lightweight, highly shielding, and minimally reflective EMI shielding composites.