Absorption-dominated Electromagnetic Interference Research Articles

Absorption dominated broadband terahertz electromagnetic shielding properties of ultrathin rGO paper

The demand for absorption-dominated terahertz (THz) electromagnetic shielding materials is critical in THz devices or components for electromagnetic compatibility and protection. However, it is challenging to find out a ultrathin, absorption-dominated shielding material with high absorptivity in a broad range. Herein, we demonstrate the hydrogen iodine (HI) acid reduced graphene oxide (rGO) ultrathin paper as a promising candidate for absorption-dominated electromagnetic interference (EMI) shielding. By optimizing the conductivity and layered structures, rGO paper with thickness of only 13 μm exhibited an absorption-dominated EMI shielding effectiveness (SE) of 21.09 dB in a broad band from 0.2 to 1.2 THz. Simple stacking of the rGO papers further improved the EMI SE up to 42.53 dB with a total thickness of 40 μm. rGO papers can also be integrated into structured substrates for applications in different scenarios. Covering a single rGO paper onto the wedge structure array, a broadband THz absorption over 99% can be achieved. Similarly, combining rGO papers and arrays of zinc pyramids, and the average SE and the max THz absorption were enhanced to 54.83 dB and 99.986%, respectively. We believe this absorption-dominated THz shielding rGO paper paves an efficient avenue towards high performance THz shielding/absorption devices for diverse applications.

Absorption-dominant electromagnetic interference shielding material using MXene-coated polyvinylidene fluoride foam

MXene (Ti3C2Tx), known for its exceptional electrical conductivity, unique two-dimensional structure, extensive surface functionality, and hydrophilicity, has emerged as a leading candidate for electromagnetic interference (EMI) shielding applications. Despite these excellent characteristics, EMI shielding materials based on MXene mostly utilize the reflection mechanism, which may cause secondary interferences. This study introduces an approach to utilize MXene as absorption-dominant EMI shielding materials. By engineering a porous layer of polyvinylidene fluoride (PVDF) atop MXene nanoflakes, we achieved a synergistic enhancement in EMI shielding effectiveness (SE) and absorptivity. The PVDF foam serves as an effective impedance matching layer, substantially enhancing the absorption of electromagnetic waves into the shielding material. Incorporating electrically conductive MXene nanoflakes to form a thin film creates a robust conductive network, fully leveraging its inherent performance. This network efficiently dissipates EM waves, thereby significantly enhancing the EMI SE. The shielding performance of this composite was thoroughly evaluated across both the X-band (8.2 GHz–12.4 GHz) and the Ka-band (26.5 GHz–40 GHz) frequencies. It demonstrated high EMI SE, attributed to mechanisms predominantly based on absorption. Specifically, it achieved an EMI SE of approximately 63.3 dB with high absorptivity (0.74) in the X-band and approximately 73.3 dB with high absorptivity (0.85) in the Ka-band. These findings underscore its potential as a route to develop absorption-dominant EMI shielding materials.

Aromatic phase change microspheres constructed nanocomposite films for fluorine-free self-cleaning, absorption-dominated EMI shielding, and high-temperature thermal camouflage

The combination of high shielding effectiveness and excellent thermal insulation is highly attractive for electromagnetic interference (EMI) shielding materials, yet remains challenging in the absence of thermal stability and self-cleaning effect. Here, poly(arylene ether nitrile) (PEN), an aromatic super engineering polymer, is synthesized and one-step self-assembled into phase-changeable microspheres in an oil-in-water microemulsion system, synchronously settling thermal lability and leakproof of conventional phase change materials. Pre-functionalized multi-wall carbon nanotubes are subsequently immobilized on PEN-based phase change microspheres for EMI shielding and thermal camouflage compartments. The resultant compartments are integrated into macroscopical nanocomposite films with segregated structures via hot-compressing densification. Due to the 3D interconnected cavities, the shielding effectiveness of the PEN-based nanocomposite film is strikingly up to 43 dB with an excellent absorption coefficient of 0.99. Meanwhile, the nanocomposite film exhibits outstanding thermal camouflage throughout a wide temperature range of 80 to 200 °C at a low thickness of ∼1.5 mm. Interestingly, superb fluorine-free self-cleaning is endowed with its inherent hydrophobic surface (contact angle up to 148.6°) overlaid with micropapillaes. Our work sheds light on such application integration of fluorine-free self-cleaning, absorption-dominated EMI shielding, and high-temperature thermal camouflage.

Capillarity-assisted assembly of composite fibers to enable highly conductive fabrics for electromagnetic interference shielding

Poor adhesion between silver nanomaterials and substrates seriously restricts the development of electronic composite devices. In this work, flexible and conductive silver nanowires/fibroin/degummed silk (AgNWs/fibroin/dSF) composite fibers with high adhesion and conductivity via capillarity-assisted assembly for electromagnetic interference (EMI) shielding are designed and fabricated by a facile and scalable all-solution dip-coating method. The nanocomposite fiber possesses high conductivity with a resistance of 8.8 Ω/cm at a low AgNWs/fibroin loading of 19.3 wt%. The assistance of the capillary force in the fiber highly increases the mass of deposited AgNWs. Furthermore, the AgNWs show high adhesion on the fibers in the tape-peel test. The enhanced deposition factors and mechanisms are detailly investigated. Moreover, the composite fibers are further woven into a soft and flexible fabric. The composite fabric shows an absorption-dominated EMI shielding performance with an efficient shielding effectiveness of 38 dB. The capillarity-assisted assembly is an attractive procedure for constructing high-conductive and uniform coatings for a wide application.

Janus structure design of polyimide composite foam for absorption-dominated EMI shielding and thermal insulation

In the present work, by virtue of the synergistic and independent effects of Janus structure, an asymmetric nickel-chain/multiwall carbon nanotube/polyimide (Ni/MWCNTs/PI) composite foam with absorption-dominated electromagnetic interference (EMI) shielding and thermal insulation performances was successfully fabricated through an ordered casting and directional freeze-drying strategy. Water-soluble polyamic acid (PAA) was chosen to match the oriented freeze-drying method to acquire oriented pores, and the thermal imidization process from PAA to PI exactly eliminated the interface of the multilayered structure. By controlling the electro-magnetic gradient and propagation path of the incident microwaves in the MWCNT/PI and Ni/PI layers, the PI composite foam exhibited an efficient EMI SE of 55.8 dB in the X-band with extremely low reflection characteristics (R = 0.22). The asymmetric conductive network also greatly preserved the thermal insulation properties of PI. The thermal conductivity (TC) of the Ni/MWCNT/PI composite foam was as low as 0.032 W/(m K). In addition, owing to the elimination of MWCNT/PI and Ni/PI interfaces during the thermal imidization process, the composite foam showed satisfactory compressive strength. The fabricated PI composite foam could provide reliable electromagnetic protection in complex applications and withstand high temperatures, which has great potential in cutting-edge applications such as advanced aircraft.

Structural Design for EMI Shielding: From Underlying Mechanisms to Common Pitfalls.

Modern human civilization deeply relies on the rapid advancement of cutting-edge electronic systems that have revolutionized communication, education, aviation, and entertainment. However, the electromagnetic interference (EMI) generated by digital systems poses a significant threat to the society, potentially leading to a future crisis. While numerous efforts are made to develop nanotechnological shielding systems to mitigate the detrimental effects of EMI, there is limited focus on creating absorption-dominant shielding solutions. Achieving absorption-dominant EMI shields requires careful structural design engineering, starting from the smallest components and considering the most effective electromagnetic wave attenuating factors. This review offers a comprehensive overview of shielding structures, emphasizing the critical elements of absorption-dominant shielding design, shielding mechanisms, limitations of both traditional and nanotechnological EMI shields, and common misconceptions about the foundational principles of EMI shielding science. This systematic review serves as a scientific guide for designing shielding structures that prioritize absorption, highlighting an often-overlooked aspect of shielding science.

An Integrated Approach for Piezo-Electrochemical Nanoenergy Generation, Storage, and Real-Time Electromagnetic Interference Shielding Control.

The extensive utilization of high-end wireless electronic equipment in medical, robotics, satellite, and military communications has created a pressing challenge for real-time electromagnetic interference (EMI) control. Herein, a piezo-powered self-chargeable supercapacitor (PPSC) architecture based on an iron-doped graphitic nitride (Fe-g-C3N4: FGN) electrode with a solid piezoelectrolyte is devised, which can provide real-time controlled EMI shielding through piezo-powered self-charging voltage (SCV). This PPSC device along with real-time SCV-controlled EMI shielding also integrates additional features like nanoenergy generation and storing capability. The results demonstrate that the PPSC device is capable of exhibiting a piezo-tuned self-charging ability of up to 669.2 mV under 9.47 N of dynamic pressing for 180 s. The SCV electrostatically modifies the PPSC device that causes destructive interference and governs the absorption of electromagnetic radiation (EMR) and controls the absorption-dominated EMI shielding up to 59.2 dB at 500 mV. Additionally, the SCV-led electrification of the PPSC device also controls a unique functional transition from the EMR reflector to the EMR absorber at ∼90 mV. Hence, this strategy of tailored absorption and reflection adjustments of EMR could also potentially contribute toward the advancement of stealth technology for military armaments with externally controlled stealth capabilities.

Reduced graphene oxide-manganese ferrite/zinc oxide nanorods coated carbonized cotton fabric for absorption-dominant electromagnetic interference shielding

In this interconnected world, safeguarding electronic devices from electromagnetic interference (EMI) is crucial. This study introduces an innovative approach to enhance EMI shielding by synergistically coating cotton fabric with vertically aligned zinc oxide nanorods (ZnO NRs) and reduced graphene oxide-magnetic ferrite nanoparticles (RGO-MF). Vertical ZnO NRs coating is achieved by seeding cotton fabric with ZnO nanoparticles, followed by hydrothermal NR growth. Subsequently, uniform RGO-MF coating is carried out by spraying a solution of graphene oxide-MF nanoparticles onto ZnO NRs coated cotton, followed by thermal annealing to reduce graphene oxide. Our observations reveal that EMI shielding effectiveness increases with RGO loading, while reflection loss decreases due to enhanced cotton fabric conductivity. Careful optimization of RGO-MF on ZnO NRs coated cotton is demonstrated. The incorporation of MF nanoparticles not only improves EMI shielding but also enhances reflection loss, highlighting the shield's absorption-dominant nature. The resulting RGO-MF/ZnO NRs coated cotton exhibits a high total EMI shielding effectiveness of ∼55 dB, reflection loss of 6.8 dB, and an absorption coefficient of 74.5 %, which attribute to the remarkable dielectric properties of ZnO NRs, the exceptional conductivity of RGO sheets, the strong magnetism of MF nanoparticles, and the enhanced core-shell structure of the cotton fabric with these materials.

Enhanced polarization via Joule heating in wood-derived carbon materials for absorption-dominated EMI shielding.

To cope with sophisticated application scenarios, carbon materials can provide opportunities for integrating multi-functionalities into superior electromagnetic interference (EMI) shielding properties. Nevertheless, carbon materials usually possess high electrical conductivity, which allows them to counteract electromagnetic waves by reflection. Moreover, the identification of factors that dominate the shielding mechanisms has typically been result-oriented, leading to a reliance on a trial-and-error approach for the development of shielding materials. Thus, it is crucial to identify the dominant factors for EMI shielding and elucidate the mechanism underlying the coordination of the balance between reflection and absorption in carbon materials. In this study, we developed a promising and viable approach to create Co@CNTs embedded in carbonized wood (CW) via chemical vapor deposition, producing Co@CNTs/CW foams. The CNTs, densely grown on the CW surface, tightly encapsulated the Co nanoparticles within them. By manipulating the Co content, the defect density and CNT length varied within the Co@CNTs. Through first-principles calculations, these variations substantially influenced the work function, charge density, and dipole moment of the Co@CNTs. Thus, defect-induced and interfacial polarizations were improved, inducing a transformation of the shielding mechanism from reflection to absorption. Regarding the Co@CNTs/CW foams, while high conductivity was essential for achieving satisfactory shielding performance, the enhanced polarization loss dominated the contribution of absorption to the overall shielding effectiveness. Taking advantage of the enhanced polarizations, the Co@CNTs/CW foams exhibited an impressive shielding effectiveness of 42.0 dB, along with an absorptivity of 0.64, which were instrumental in effectively minimizing secondary reflections. Remarkably, these as-prepared foams possessed outstanding hydrophobicity and Joule heating features with a water contact angle of 138° and a saturation temperature of 85.5 °C (2.5 V). Through the stimulation of voltage-driven Joule heating, the absorptivity of Co@CNTs/CW foams can be significantly enhanced to a range of 0.61 to 0.73, irrespective of the Co content. This research would provide a new avenue for designing carbon materials with an absorption-dominated mechanism integrated into EMI shielding performance.

3D graphene decorated with nickel nanoparticles: in situ synthesis, enhanced dispersibility, and absorption-dominated electromagnetic interference shielding

Utilizing the complexation of carboxyl groups with Ni(ii), 3D graphene with highly dispersed Ni NPs was achieved via laser fabrication.

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.

Dual cross-linked and vertically oriented MXene/polyvinyl alcohol aerogel for ultrabroadband electromagnetic interference shielding and thermal camouflage

Lightweight and porous conductive aerogels have demonstrated great potential in electromagnetic interference (EMI) shielding and thermal camouflage, while the poor mechanical properties and structural stability usually limit their applications. Herein, vertically oriented and physically/chemically dual cross-linked Ti3C2TX MXene/polyvinyl alcohol (PVA) composite aerogel is prepared by ice-templated unidirectional freezing process and subsequent glutaraldehyde (GA) treatment. GA induced covalent crosslinking leads to the significantly enhanced structural stability and mechanical strength of the resultant MXene/PVA composite aerogels, which also endows them with desirable flame retardancy. The honeycomb-like structure of the composite aerogel contributes to its good anisotropic absorption-dominated EMI shielding performance over an ultrabroadband frequency range (8.2–40 GHz) with a low MXene content of 3.81 vol%. Furthermore, the excellent thermal insulation properties and low infrared emissivity of the highly oriented arranged MXene sheets bring the composite aerogel promising applications in thermal camouflage. Therefore, the lightweight and robust MXene/PVA composite aerogel demonstrates great potential in multi-scenario applications as a high-performance multifunctional EMI shielding material.

Poly(arylene ether nitrile) composite foams with magnetically and electrically separated structures for frequency-selective electromagnetic interference shielding

With the rapid development of communication technology and modern intelligent electronic systems, the demand for frequency-selective electromagnetic interference (EMI) shielding materials has grown. In this work, poly(arylene ether nitrile) (PEN) composite foams with separated magnetic and conductive layers were prepared via delayed non-solvent induced phase separation, where the distribution of magnetic and conductive layers was designed to construct double-layer asymmetric structures and sandwich structures. Benefiting from destructive interference between electromagnetic waves (EMWs) in the magnetically and electrically separated porous structures, the double-layer asymmetric composites (M−C) exhibited outstanding absorption-dominated EMI shielding performance with favorable frequency selectivity, which did not occur in conventional double-layer composites. Specifically, M−C achieved a maximum shielding efficiency (SE) of 49.3 dB and a maximum average absorption ratio (Ar) of 93.9 %. Meanwhile, increasing the thickness of the magnetic layer of M−C can lower the characteristic frequency (fc) of the shielding peak and enhance average SE and average Ar. Moreover, M−C could show higher fc, average Ar, and average adsorption coefficient in the X-band when the incident EMWs first met with the magnetic layer, which was unavailable in frequency-selective PEN-based sandwich-structured composites. This effort offers a novel, flexible design to fabricate absorption-dominated EMI shielding materials with frequency selectivity.

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.

Bio-inspired flexible versatile textiles for excellent absorption-dominated electromagnetic interference shielding, thermal management, and strain sensing

Multifunctional flexible textiles are urgently required for wearable electronics and military equipment. However, it remains a big challenge for them to achieve absorption-dominated electromagnetic interference (EMI) shielding and maintain excellent multifunctionalities. Herein, inspired by hierarchical structure of muscle, a novel multilayer self-assembly strategy was proposed to conformally deposit conductive substances and absorption fillers on flexible textiles to realize superior versatility in EMI shielding, thermal management, and strain sensing. The formed muscle-like nanostructure was composed of Ag nanoparticles, Ag nanowires, MXene, and FeCo-C. Benefiting from the 3D cross-linked stable networks with high conductivity (14075.3 S·m−1), durable EMI shielding (85 dB after stretching and bending), and excellent electrical heating (116.3 °C under 1.8 V) were achieved. Based on robust electrostatic interaction between FeCo-C and MXene, strong EMW absorption was realized with a low reflection coefficient (0.168). The textile also demonstrated excellent strain sensing performance in a linear range of 5–60 % with a fast response time (121 ms) for complex motion detection. Besides, the textiles had good gas permeability, ensuring long-term wearable comfortability. This work offers a significant paradigm to construct multifunctional flexible textiles for next-generation integrated flexible electronic devices and military equipment with practical applications.

Construction of alternating multilayer films with stable absorption-dominated electromagnetic shielding performance and reinforced mechanical properties via interface engineering

As an ideal material to lessen electromagnetic pollution, absorption-dominated electromagnetic interference (EMI) shielding composites still face the problems of complicated structure design and insufficient performance stability. Herein, an alternating multilayer film with stable absorption-dominated EMI shielding effectiveness (SE) and reinforced mechanical properties is fabricated by constructing hydrogen bonding between multilayers interface. When the layers increase to 4, benefiting from the construction of multilayer structure and the stronger interaction, the reflective shielding effectiveness decrease to 2.9 dB, the absorption coefficient of multilayer film increases from 0.13 to 0.52, the retention rate of EMI SE increases from 1.0 % to 97.6 % after bending 1000 cycles, and the tensile strength is enhanced from 5.7 MPa to 27.3 MPa. The calculated binding energies and the experimental results show that the interaction between Pluronic F127 anchored on the porous film and cellulose nanofibers entangled on the carbon nanotubes layer increases the interlayer interaction force and durability of EMI SE.

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.

Phase separation-regulated fabrication of MXene/PVA cryogel sensor with effective electromagnetic interference shielding

Multifunctional hydrogels with desirable mechanical properties have attracted extensive attention in flexible electronic devices. Herein, tough and robust Ti3C2Tx MXene/polyvinyl alcohol (PVA) composite cryogel with excellent flexibility is prepared via a cyclic freeze–thaw (F-T) method. The morphological and crystalline structure of the composite cryogel is regulated by the phase separation process during fabrication, which greatly contributes to the enhanced mechanical properties. The highly flexible and stretchable MXene/PVA cryogel exhibits sensitive and reliable responses to deformations, demonstrating promising application in the detection of human motions and smart coding. Furthermore, the composite cryogel presents a high absorption-dominated electromagnetic interference (EMI) shielding effectiveness of 25 dB at an ultralow MXene loading of 0.04 wt%, which is ascribed to the synergetic effect of its tunable porous structure and water-rich environment. These findings provide valuable insights into the design and fabrication of high-performance multifunctional hydrogels.

Thermally insulating carbon nanotubes and copper ferrite based porous polydimethylsiloxane foams for absorption-dominant electromagnetic interference shielding performance

The exponential growth of the electronic and communication industry in the last 50 years raised serious concerns about electromagnetic (EM) pollution. Consequently, suitable composite materials for electromagnetic interference (EMI) shielding have been developed to reduce EM pollution. In the present work, carbon nanotubes (CNT) and copper ferrite (CuFe2O4) nanoparticle-based porous polydimethylsiloxane (PDMS) composite foams were prepared using the baking soda template method. The PDMS foam acts as the 3-dimensional (3D) porous network, CNT gives the required conductive path and magnetic CuFe2O4 provides the necessary magnetic loss, so that the resultant foams achieved high EMI shielding through the absorption mechanism. Without the inclusion of CuFe2O4, the total EMI SE of the PDMS foam is lower than 20 dB, while various contents of the added CuFe2O4 improve the EMI SE up to 32 dB at a thickness of 3 mm. In addition, the thermal insulation properties are also reported and the resultant material shows a moderately low thermal conductivity of 0.046 W m−1 K−1. These characteristics of the composite foam highlight the strong absorption-dominated EMI shielding and thermal insulation performance, allowing it to successfully meet a wide range of applications.

MXene/Ag@ZnO/WPU/Melamine gradient composite foams prepared by a unidirectional evaporation approach for absorption-dominated electromagnetic interference shielding

Gradient electromagnetic interference (EMI) shielding materials with absorption-dominated characteristics are promising but always have problems like complicated steps or harsh operation conditions. Herein, we propose a gradient EMI composite foam of MXene/Ag@ZnO/WPU/Melamine fabricated through a simple unidirectional evaporation in combination with a vacuum-drying method. Benefiting from it, the conductivity of the material decreases from the top and bottom to the middle. The top with good impedance matching, which allows electromagnetic waves to enter the material, and the bottom with an efficient conductive network, which ensures an excellent EMI SE of the composite foam, could be balanced owing to the difference in the dispersibility of MXene and Ag@ZnO. Under the effect of “absorb-reflect-reabsorb”, the as-prepared M2A3F composite material exhibits a high EMI SE of 39.90 dB and a low reflectivity coefficient of 0.1423 with an ultra-low volume ratio (2.72 % MXene and 4.25 % Ag). In addition, it features good mechanical properties, especially cyclic compression recovery. In sum, this study provides a novel solution for preparing high-performance EMI materials with absorption-dominated characteristics on a large scale.