High Electromagnetic Interference Research Articles

Compressible thermoplastic polyurethane/silver nanorod foams for absorption dominant electromagnetic interference shielding

Conductive polymer composites (CPCs) have attracted significant interest in the field of flexible electromagnetic protection, but the challenge of balancing high electromagnetic interference shielding effectiveness (EMI SE) and low reflection losses still exists. Herein, thermoplastic polyurethane/silver nanorod (TPU/AgNR) composite foams have been successfully prepared using both the salt template and vacuum-assisted thermal compression methods. By varying the AgNRs content and employing a layer-by-layer bonding approach, a gradient structure with optimized impedance matching is achieved. The “absorb-reflect-reabsorb” EM attenuation mechanism of the asymmetric gradient EMI shielding in the internal structure is exploited, resulting in TPU/AgNR foam (TAF) with high EMI SE and significantly reduced EM reflection. Notably, the three-layer foams exhibit an average shielding efficacy of 35.5 dB and a reflected power coefficient (R) of 0.085 in the X-band, thereby substantially mitigating secondary EM wave reflections. Furthermore, these foams demonstrate exemplary compressive resilience, with the sample maintaining excellent EMI shielding stability even after undergoing 100 compression cycles at 50 % strain. Consequently, a straightforward approach is employed to fabricate materials with high EMI SE and low reflectivity, offering the potential for use in EM shielding applications of next-generation flexible electronic devices.

High‐Performance Thermoelectric and Electromagnetic Interference Shielding Derived from MXene/Ag2Se Nanowire Composite Film

AbstractA flexible n‐type composite film consisting of MXene/Ag2Se nanowires (MX‐AS), is synthesized herein via a facile wet chemical sintering process. The thermoelectric properties of the composites with various MXene concentrations are systematically explored. The as‐synthesized 2D MXene exhibits homogeneous intercalation and dispersion of the Ag2Se nanowires. A comparative analysis reveals that these composite films outperform the pristine Ag2Se nanowire films fabricated using the same process. Specifically, the MX‐AS composite film containing 1.5 wt.% MXene exhibits a significant (≈1.25 times) improvement in the maximum thermoelectric power factor (PF), exhibiting a value of ≈933.4 µW m−1 K−2 at 400 K. This enhancement can be attributed to the combination of the remarkable intrinsic Seebeck coefficient of the Ag2Se and the high electrical conductivity of the MXene. Moreover, cyclic bending tests demonstrate the exceptional mechanical durability and flexibility of the composite film, with only an ≈7% decrease in the PF after 1000 cycles. In addition, the as‐prepared MX‐AS composite exhibits a high electromagnetic interference (EMI) shielding efficiency.

Liquid Metal‐Coated Textile with P(AAm‐co‐AA) Ionogel Encapsulation to Mitigate Electromagnetic Radiation Pollution

AbstractConductive textiles with electromagnetic interference (EMI) shielding functionality are highly desirable for growing flexibility requirements of EMI shielding devices. Most extant shielding coatings on textiles rely on rigid nanomaterials, which are susceptible to detachment, and generate a great deal of reflected EM waves. Thus, there is a high demand for shielding coatings on textiles that are stretchable, stable, and capable of suppressing the secondary reflection toward incident EM waves. Liquid metal is a particularly suitable candidate owing to its high electrical conductivity and excellent conformality. Herein, a straightforward coating strategy is developed for fast fabrication of Ion/Clay‐F that is reinforced with ionogel encapsulation. Especially, the method enables the direct transformation of fluid‐like liquid metal into a clay‐like state and the preparation of ionogel sealings from monomer solutions. The resulting Ion/Clay‐F exhibits promising features, including high total EMI shielding effectiveness (SET) (highest value of 49.3 dB for a single layer and an average value of 73.0 dB for three layers), low reflectivity (0.404), improved tensile strength (13.16 MPa) and tolerance in a wide range of temperatures (−18–100 °C). Remarkably, such Ion/Clay‐F outperforms pure cotton fabric in terms of thermal management, delivering superior heat dissipation and thermal insulation properties.

Ultralight Flexible Collagen Fiber Based Aerogels Derived from Leather Solid Waste for High Electromagnetic Interference Shielding.

Designing and developing high-performance shielding materials against electromagnetic interference is of utmost importance due to the rapid advancement of wireless telecommunication technologies. Such materials hold both fundamental and technological significance. A three-stage process is presented for creating ultralight, flexible aerogels from biomass to shield against electromagnetic interference. Collagen fibers sourced from leather solid waste are used for: (i) freeze-drying preparation of collagen fibers/poly(vinyl alcohol) (PVA) aerogels, (ii) adsorption of silver nanowires (AgNWs) onto collagen fiber/PVA aerogels, and (iii) Hydrophobic modification of collagen fiber/PVA/AgNWs aerogels with 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane (POTS). Scanning electron microscopy studies reveal that an interweaving of AgNWs and collagen fiber/PVA porous network has formed a conductive network, exhibiting an electrical conductivity of 103 S·m-1. The electromagnetic interference shielding effectiveness reached more than 62 dB, while the density was merely 5.8 mg/cm3. The collagen fiber/PVA/AgNWs/POTS aerogel displayed an even better electromagnetic shielding efficiency of 73 dB and water contact angle of 147°. The study results emphasize the distinctive capacity of leather solid waste to generate cost-effective, ecofriendly, and highly efficient electromagnetic interference shielding materials.

A Comprehensive Investigation into Bidirectional DC-DC Converters with Soft Switching for Electric Vehicles

Electric vehicles (EVs) are one of the the promising solutions for the environmental issues such as carbon emission and global warming. The high voltage traction battery in EVs is charged from utility grid by an EV charger. The Society of Automotive Engineers (SAE) standardize EV charges into two categories on-board chargers and off-board chargers. Usually, the on-board chargers are located inside the vehicle whereas, off-board chargers are not mounted on the vehicle. For onboard chargers, size and power density of charger become a prior matter of concern. The only way to reduce the size of a converter and thereby increase the power density is to operate power electronic conversion system (PECS) at very high switching frequency (HSF) resulting in reduced size of magnetic component in the charger configuration. However, HSF operation may lead to a high electromagnetic interference (EMI), loss in switch and switch duty. The work in this paper is focused on the development of high frequency bi-directional DC-DC converter (BD2C) stage priory used in on-board chargers due to distributed sources of energy as well as to manage the power distribution in the configuration. The power electronic BDCs are derived from boost and buck unit. The boost derived converter are current fed converters and offers advantages in terms of inherent voltage gain, short circuit protection and lower input current ripple. The voltage spikes across switches, high rated device selection, hard switching, snubber and auxiliary circuit requirements are some of the undesirable factors. This occurrence happened due to unbalance power transfer by the power electronics converter. Similarly, voltage fed converter offers good voltage control during power transfer.

Flexible Sandwich-Shaped Cellulose Nanocrystals/Silver Nanowires/MXene Films Exhibit Efficient Electromagnetic-Shielding Interference Performance.

The electromagnetic pollution problem is becoming increasingly serious due to the speedy advance of electronic communication devices. There are broad application prospects for the development of flexible, wearable composite films with high electromagnetic interference (EMI)-shielding performance. The MX@AC composite films were prepared from MXene, silver nanowires (AgNWs) and cellulose nanocrystals (CNCs) with a sandwich structure. Benefiting from the upper and lower frame structure formed by winding 1D AgNWs and CNC, the tensile strength of the MX@AC was improved to 35 MPa (12.5 wt% CNC content) from 4 MPa (0 wt% CNC content). The high conductivity of MXene and AgNWs resulted in the MX@AC composite film conductivity up to 90,670 S/m, EMI SE for 90 dB, as well as SSE/t up to 7797 dB cm2 g-1. And the MX@AC composite film was tested for practical application, showing that it can effectively isolate electromagnetic waves in practical application.

ITO/Cu-mesh transparent conductive film with high weather resistance and electromagnetic interference shielding effectiveness

ITO/Cu-mesh transparent conductive film with high weather resistance and electromagnetic interference shielding effectiveness

Enhancing thermal conductivity and electromagnetic shielding performance of Ni-CNT/Al2O3/PVDF composite film with a multi-layered structure

To develop thermal interface materials with both high thermal conductivity and electromagnetic interference shielding, the polyvinylidene fluoride (PVDF) composite film was prepared by electrospinning and hot-pressing, using strategies of multi-layered structure and two fillers synergy of nickel modified carbon nanotube (Ni-CNT) and Al2O3 microspheres. The composite film consisted of a Ni-CNT filled PVDF electrospun fiber film as the top and bottom surface layers, and a PVDF electrospun fiber film electrostatically adsorbing Al2O3 microspheres and surface-sprayed with Ni-CNT as the middle layer. At a 20 wt% Ni-CNT in the surface layers and a 16.7 wt% Al2O3 and 5 wt% Ni-CNT in the middle layer, the composite film with a thickness of 0.1 mm exhibited optimal performances with electromagnetic wave shielding efficiency of 65 dB in the frequency range of 8.2–12.4 GHz, with 86% of the electromagnetic waves being absorbed. At the same time, the composite film had a high in-plane thermal conductivity of 4.02 W m−1 K−1, while maintaining a tensile strength of 25 MPa and flexibility.

Two birds with one stone: High electromagnetic interference shielding effectiveness and high thermal conductivity of ternary polyvinyl alcohol/graphene/ carbonyl iron nanocomposite films

Gaining brilliant flexible, easily-processable, bendable, low-density and high electrical conductivity (σ) materials with an excellent electromagnetic-interference (EMI) shielding performance is urgently needed in the fields of aerospace, aircraft, military, wearable and portable electronic industries. Therefore, the growing desire towards miniaturizing and developing high-frequency electronics is increasing incredibly today and grabbing much attention, however, they cause extreme heat accumulation and EM radiations that affect their performances as well as their hazardous effects on human health. So, polymer nanocomposites with high thermal conductivity (k) and EMI shielding effectiveness (SE) synchronously are urgently required to consume the generated heat and blocks the EM waves. Herein, poly(vinyl alcohol)/graphene nanosheets/carbonyl iron (PVA/GRx/CIR0.1-x) nanocomposite films are introduced as a new alternative candidate for EMI shielding applications with high in-plane k//, high mechanical functions, and EMI SET performance. The synergistic effect of GR and CIR on EMI shielding functions, thermal stability, mechanical properties, electrical features, and surface morphology has been explored. The increase in GR(x) amounts provides continuous GR layers and dense networks for conducting electrons and heats, provides the films with an admirable k// and total SE (SET) synchronously. Particularly, the PVA/GR0.08/CIR0.02 films have shown an σ of 1.72 Sm−1, a large SET of 32.94 dB and a specific SE (SSE/t) of 4365 dBcm2g−1 due to the mutual role (effect) of both high electrical conductive graphene and high magnetic carbonyl iron in cancelling the magnetic and electric fields of the incident EM waves. Moreover, the layered structure of GR endows films with a high k// of 3.62±0.11 W/(m·K), which is 14-fold larger than that of green PVA. The high compatibility and fine dispersion of GR/CIR fillers endow the films with a high Young modulus of 2.16 GPa, which is 7-fold larger than that of green PVA. This work suggests a novel and feasible scheme for producing high EMI shielding and high thermal conductive polymeric films, which will have huge prospects in advanced technology such as electromagnetic (microwave) interference shielding, wearable, biological, smart fabrics, military technologies and electronic equipments.

Highly thermally conductive and EMI shielding composite fabricated via free‐radical polymerization of poly acrylic acid assisted by expanded graphite with liquid metal‐grafted MXene

AbstractPolymer composites offer numerous benefits, including low cost, easy processability, and diverse applications. In this work, we fabricated a composite material with high thermal conductivity and electromagnetic interference (EMI) shielding performance using EGaIn, a liquid metal (referred to as LM in this paper), MXene (MX), and expanded graphite (EG) as multifunctional fillers, along with polyacrylic acid (PAA). LM was used to exfoliate MX under the effect of shear force, which not only reduced the size of MX but also increased the aspect ratio of the 2D‐structured MX. MX was filled into the pores of EG to make a heat transfer path, thereby enhancing its thermal conductivity, mechanical properties, and EMI SE properties. LM served as the initiator of free‐radical polymerization to convert acrylic acid (AA) into PAA. Finally, the LMMX/EG/PAA composite was hot‐pressed to make the heat‐transfer path dense. As a result, the LMMX/EG/PAA composite exhibited a thermal conductivity of 1.88 W/m·K and an EMI shielding effect of 52 dB.

2D/0D multiscale interfacial engineering of carbon fiber composites for simultaneous achieving high mechanical and electromagnetic interference shielding properties

AbstractIn the face of escalating electromagnetic pollution, it is urgently needed to expedite the development of innovative carbon fiber reinforced polymer (CFRP) composites that not only demonstrate superior mechanical properties as well as durability but also boast exceptional electromagnetic interference shielding (EMI) performance. However, given the absence of robust interface interactions and the lack of an outstanding nanostructured conductive network, there remains a need to further elevate the overall performance of CFRP composites. Herein, a highly continuous conductive network by integrating 2D MXene and 0D Ag nanoparticles with strong interlayer interactions was constructed through point‐to‐plane conductive modes, facilitated by polydopamine (PDA). Thanks to the excellent electromagnetic wave loss and the unique multi‐dimensional structure arising from the optimizing interfacial engineering, the EMI shielding effectiveness of the modified CF‐PDA‐M‐Ag/EP composite achieved a remarkable 45.9 dB, obtaining a 99.5% enhancement compared with the neat CF/EP. The synergistic effect resulting from the multi‐dimensional structure and strong interaction can improve the interfacial shear strength (IFSS), interlaminar shear strength (ILSS) and flexure strength of the composite up to 81.9, 85.8 and 864.6 MPa, respectively, far superior to the unmodified composite materials. This research provides a dependable and convenient approach for exploiting high‐performance CFRP composites with intriguing electromagnetic interference (EMI) shielding properties.Highlights An optimizing multifunctional 2D/0D interface for carbon fiber was designed. A highly conductive network via the point‐to‐plane conductive mode. The EMI shielding effectiveness of the composite reached up to 45.9 dB.

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.

Multilayered silver nanowires and graphene fluoride-based aramid nanofibers for excellent thermoconductive electromagnetic interference shielding materials with low-reflection

Multilayered films composed of alternating layers of graphene fluoride (GF) and silver nanowires (AgNWs) in an aramid nanofiber (ANF) matrix were fabricated. The films were prepared by sequential vacuum filtration of GF@ANF and AgNWs@ANF suspensions to obtain multilayered composite architectures. The multilayered GF@ANF/AgNWs@ANF films exhibited exceptional mechanical flexibility and strength, with tensile strength up to 130 MPa and 5000 bending cycles with negligible performance deterioration. The films displayed remarkably high electromagnetic interference (EMI) shielding effectiveness up to 54 dB in X-band frequencies, attributed to the multiple internal reflections in the multilayered structure. EMI shielding was dominated by absorption rather than reflection, enabling attenuation of incident microwaves without secondary pollution. The multilayered films also exhibited ultrahigh in-plane thermal conductivity of up to 45 W/mK, owing to the thermally conductive GF and AgNWs networks. The EMI shielding effectiveness and thermal conductivity were retained after temperature and bending cycling. The composite films also demonstrated excellent flame retardancy. This study provides an effective route toward concurrent enhancement of multi-functional properties through architectural engineering at the nanoscale. The combination of robust EMI shielding, mechanical flexibility, thermal management, and fire safety highlights the potential of rationally designed multilayered composites for practical applications in 5 G wearable electronics devices, communications systems, and radar technologies.

Sandwich-Like Flexible Breathable Strain Sensor with Tunable Thermal Regulation Capability for Human Motion Monitoring.

High-performance flexible strain sensors with synergistic and outstanding thermal regulation function are poised to make a significant impact on next-generation multifunctional sensors. However, it has long been intractable to optimize the sensing performance and high thermal conductivity simultaneously. Herein, a novel flexible sandwich-like strain sensor with advanced thermal regulation capability was prepared by assembling electrospun thermoplastic polyurethane (TPU) fibrous membrane, MXene layer, and TPU/boron nitride nanosheet (BNNS) composite films. The as-prepared sensor demonstrates a wide strain working range (∼100% strain), an ultrahigh gauge factor (2080.9), and a satisfactory reliability. Meanwhile, benefiting from the uniform dispersion and promising orientation of BNNSs in TPU composites, the sensor possesses a high thermal conductivity of 1.5 W·m-1·K-1, guaranteeing wearer comfort. Additionally, the unique structure endows the sensor with high stretchability, breathability, biocompatibility, and tunable electromagnetic interference shielding performances. Furthermore, an integrated wireless motion monitoring device based on this sensor is rationally designed. It exhibits a fast response time, a wide recognition range, and the ability to maintain skin temperature during prolonged physical activity. These encouraging findings provide a new and feasible approach to designing high-performance and versatile flexible strain sensors with broad applications in advanced wearable technology.

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.

New construction strategies of carbon‐based composites for flexible electromagnetic interference shielding films

AbstractDue to the quick growth of portable/wearable devices and electronics, the development of high efficiency flexible electromagnetic interference shielding films is a hot research topic. This work discusses the latest advances in flexible carbon‐based electromagnetic interference shielding films, such as constructing desirable structures, combining with magnetic constituents, and filling with polymer matrices. The new construction strategies, preparation methods, performances, and associated mechanisms are summarized. Moreover, the synergism, multifunctionality, and potential application of outstanding carbon‐based electromagnetic interference shielding films including graphene‐based, CNT‐based, and carbon fiber‐based films are analyzed in detail. Additionally, some significant issues and prospective views on carbon‐based composites as flexible electromagnetic interference shielding films are also presented.Highlights The latest progress of flexible carbon‐based EMI shielding films Constructing desirable structure, synergizing with others, designing CPCs The relationship between preparation, structure, property, and mechanisms The synergism, multifunctionality, application of EMI shielding films Key challenges and future perspectives of carbon‐based EMI shielding films

Electromagnetic shielding, absorption and physicochemical evaluations of Fe3N @ C nanocomposite decorated with Poly(DCBP-co-BT) for absorption application in 8-12 GHz

Multipurpose electromagnetic shielding materials with high absorption and low reflection are a potential topic for upcoming advancement in the fabrication industry. Nevertheless, the task of effectively incorporating these traits into the same material remains challenging. In the current work, Fe3N @ C nanocomposite wrapped in Poly(4,4′-di(N-carbazoyl)bipheny-co-2,2′-bithiophene) polymer is fabricated for absorbance-based shielding material which exhibits significant absorbance and minimal reflection characteristics. The microwave absorption features of as-synthesized material were studied for different loading ratios and it has achieved minimum reflection loss (RLmini) of − 39 dB having 2.0 mm thickness for 8 wt% loading sample. Shielding effectiveness of the fabricated nanocomposite was also measured, and the sample with 8 wt% filler loading had a high electromagnetic interference shielding efficacy of − 60 dB at 8.5 GHz. Additionally, high absorption capacity (−30 dB) and excellent shielding effectiveness (−60 dB) make this nanocomposite a special one that may be used as a radar-absorbing coating to shield against electromagnetic radiation interference. Thus, such adaptive shielding material possesses essential uses in electromagnetic shielding due to its exceptional capacity for absorption and remarkable efficiency in shielding.

Metaheuristic aided structural topology optimization method for heat sink design with low electromagnetic interference

This study investigates the application of the Metaheuristic Aided Structural Topology Optimization (MASTO) method as a novel approach to address the multiphysics design challenge of creating a heat sink with both high heat conductivity and minimal Electromagnetic Interference (EMI). A distinctive 2D layout with elongated fins is examined for electromagnetic traits, highlighting resonance-related EMI concerns. MASTO proves to be a valuable tool for navigating the complex design space, yielding thoughtfully optimized solutions that harmonize efficient heat dissipation with effective EMI control. By merging simulation findings with practical observations, this study underscores the potential of the MASTO method in achieving effective designs for intricate multiphysics optimization problems. Specifically, the method's capacity to address the complex interplay of heat transfer with convection and the suppression of electromagnetic emissions is showcased. Moreover, the study demonstrates the feasibility of translating these solutions into tangible outcomes through manufacturing processes.

Catechol grafted rGO/MXene heterosheet structures for high performance electromagnetic interference shielding and thermal management applications

Two-dimensional MXenes have shown extraordinary potential in various scientific areas, including energy harvesting and microwave shielding. Despite their outstanding properties, MXene-based scaffolds suffer from vulnerable mechanical fragility and environmental instability, which reduces the operational life. Here, we used a nature-inspired strong surface adhesion to assemble a stacked heterosheet structure of reduced graphene oxide (rGO) and MXene (Ti3C2TX). Catechol bonding of self-triggered polydopamine between these two-dimensional nanofillers resulted in a dense and well-ordered structure, transforming their mechanical and electrical properties to those of a freestanding sheet. The simultaneous grafting of catechol and the formation of stacked heterosheets with rGO not only protects the MXene sheets from environmental oxidation but also preserves their intrinsic transportation properties. The resulting rGO/MXene composite sheet was ordered and dense, with a tensile strength of 86 MPa and toughness 118.2 MJm−3. The ultrathin, highly flexible, and conductive (26.5 Scm−1) composite sheet exhibited specific shielding effectiveness of 16340, 19136 and 21340 dBcm2g−1 in the X, Ku, and K bands, respectively. Additionally, it showed outstanding Joule-heating properties, with a rapid thermal response of approximately 2 s and the ability to reach a saturation temperature >120 °C at a relatively low supplied voltage of <7 V. The grafted rGO/MXene composite sheet maintained its transportation properties, electromagnetic interference shielding, and electrothermal properties even after 60days of continuous exposure to ambient by suppressing oxidation attacks. The synergistic enhancement of physical properties and environmental stability in the composite sheet suggest a great potential for high-performance, flexible shielding, and thermal management applications in aerospace and automobile electronics.

MXene/PDMS composite foam with regulatable cell structures for improved EMI shielding performance

AbstractThe construction of conductive network and the design of material structure are the key points of polymer‐based shielding materials. Herein, we reported a MXene/PDMS composite foam material with adjustable cell structure and high efficiency electromagnetic interference (EMI) shielding. Few‐layered MXene is used as a conductive filler to construct three‐dimensional conductive networks by in situ chemical etching. Meanwhile, a series of polystyrene microspheres with different sizes were prepared by applying suspension polymerization method as templates to introduce different cell sizes and densities for PDMS‐based materials. The density and EMI shielding performance of composites can be improved by adjusting the cell structure. Compared with the unfoamed MXene/PDMS composites, the composite foam in this work not only reduces the material density greatly but also improves the microwave absorption performance with smaller cell size. This method provides a simple and effective guide for changing material density and absorbing mechanism by introducing cell structure into polymer‐based materials in the future.