High-performance Electromagnetic Interference Shielding Research Articles

MXene-decorated carbonized jute composite for high-performance electromagnetic interference shielding

Lightweight, good processability and efficient electromagnetic interference (EMI) shielding materials have captured more interest with the recognition of electromagnetic pollution hazards. Biomass-based carbon has been considered as a promising EMI shielding due to its low cost, renewability and environmental friendliness. Here, we used jute felt as the precursor of biomass carbon to fabricate the MXene (Ti3C2Tx)/jute composite (MXene/CJ) via a simple carbonization process and dip-and-dry method. Higher carbonization temperature and more MXene loading are conducive to electrical conductivity and shielding effectiveness (SE). When the carbonization temperature was 900 °C and dip-and-dry times was 3, the average EMI SE of 59.08 dB was achieved in 8.2–12.4 GHz (X-band) with a reflection-dominated mechanism. Besides, the composite also exhibits the potential to be used as a strain sensor. Under small pressure, the composite possessed excellent sensitivity and response time. The wrist bending, swallowing and vocal cord vibration can be monitored in real-time. These results illustrate that the MXene/CJ composite has a broad prospect in the EMI shielding and wearable electronics fields. This work also provided a feasible approach for the high-value utilization of natural biomass resources.

Progress in the Foaming of Polymer-based Electromagnetic Interference Shielding Composites by Supercritical CO2.

As a critical action plan formulated for peaking carbon dioxide emissions, polymeric electromagnetic interference (EMI) shielding materials based on CO2 foaming technology have recently been attracting widespread attention in both research and industry, attributable to their efficient use of CO2 , high specific strength, corrosion resistance and low-cost characteristics. In the past decade, the emergence of novel design concepts and preparation techniques for CO2 foaming technology has led to the development of new high-performance EMI shielding materials in this field. This review summarizes the research progress made to date on the fabrication of EMI shielding composite foams by supercritical carbon dioxide (scCO2 ) foaming. We also explore the structure-activity relationships between the component/distribution and EMI shielding properties. Additionally, the application prospects and development challenges of new EMI shielding composite foams are described.

Facile fabrication of flexible and ultrathin self-assembled Ti3C2Tx/bacterial cellulose composite films with multifunctional electromagnetic shielding and photothermal conversion performances

With the rapid development of modern electronics, the next generation of electromagnetic interference (EMI) shielding materials requires ultrathin, lightweight, flexibility and robustness to protect electronic devices from radiation pollution. In this study, the multifunctional Ti3C2Tx/Bacterial Cellulose (Ti3C2Tx/BC) composite films with uniformly lamellar structures have been developed by combining experimental and theoretical works. The microstructures, mechanical properties, EMI shielding and photothermal conversion performances of Ti3C2Tx/BC composite films have been systematically investigated. It is highlighted that the resultant ultrathin and flexible Ti3C2Tx/BC composite film with a Ti3C2Tx content of 50 wt% exhibits satisfactory tensile strength of 109.6 ± 4.5 MPa, excellent electrical conductivity of 5020 S m−1 and EMI SE value of 43.7 dB. More interestingly, the composite film displays stable and fast-response photothermal characteristics, with the photothermal conversion temperature up to 74.5 ℃. This study proposes a versatile strategy to synthesize multifunctional MXene/BC composite films with satisfactory mechanical properties, high performance EMI shielding and photothermal conversion effects, which shows great potential for the protection of electronic devices.

Fe3O4 uniformly decorated reduced graphene oxide aerogel for epoxy nanocomposites with high EMI shielding performance

This work reports the successful fabrication of Fe3O4@anisotropic reduced graphene oxide aerogel/epoxy (Fe3O4@AGA/EP) nanocomposites, with outstanding electromagnetic interference (EMI) shielding performance and mechanical properties. One-step hydrothermal reduction reaction and unidirectional freezing approach were utilized in order to avoid the agglomeration of Fe3O4 and graphene oxide (GO). The Fe3O4@AGA/EP nanocomposites were subsequently obtained by freeze-drying, annealing treatment, EP infiltrating and curing processes. Due to the synergistic effect of the Fe3O4 (with magnetic and dielectric loss properties) and the three-dimensional AGA framework (presents high electrical conductivity), the EMI shielding efficiency of Fe3O4@AGA/EP nanocomposites reached 40.4 dB along the radial direction when the mass ratio of FeSO4: GO was 2: 1. Simultaneously, an enhanced storage modulus of 116% was exhibited compared with that of the pure EP. Moreover, the nanocomposites showed absorption-dominated EMI shielding characteristics, which is significant for the reduction of secondary pollution of electromagnetic waves. This research provides a one-step hydrothermal reduction method to address the agglomeration of Fe3O4 and prepare EP-based composites with high EMI shielding performance and mechanical properties.

C60 intercalating Ti3C2T MXenes assisted by γ-cyclodextrin for electromagnetic interference shielding films with high stability

Ti3C2Tx MXenes with excellent metallic conductivity and flexibility have shown a promising prospect as electromagnetic interference (EMI) shielding materials. Ultrathin, hierarchical hybrid films were fabricated by using C60 intercalating Ti3C2Tx MXenes with the assistance of water-soluble γ-cyclodextrin (CD). The C60/CD complex was obtained by high-speed vibration milling using hydrophilic CD as dispersing agent. After thermal annealing treatment, the obtained hybrid film exhibited excellent EMI shielding (53.52±0.43 dB), hydrophobicity (water contact angle: 93.7°) and mechanical stability (over 0.9 million bending times). Taking advantage of the antioxidant of C60, the chemical durability of Ti3C2Tx MXenes based hybrid films was also improved as expected. These results indicate that the well-designed hierarchical hybrid films with the intercalation of C60 have promising potential for high-performance EMI shielding applications.

Tuning the Self-Assembled Morphology of Ti3C2Tx MXene-Based Hybrids for High-Performance Electromagnetic Interference Shielding.

Hybrid materials based on transition metal carbide and nitride (MXene) nanosheets have great potential for electromagnetic interference (EMI) shielding due to their excellent electrical conductivity. However, the performance of final products depends not only on the properties of constituent components but also on the morphology of the assembly. Here, via the controlled diffusion of positively charged poly(allylamine hydrochloride) (PAH) chains into the negatively charged Ti3C2Tx MXene suspension, MXene/PAH hybrids in the forms of thin films, porous structures, and fibers with distinguished internal morphologies are obtained. Our results confirm that PAH chains could effectively enhance the oxidation stability and integrity of wet and dry MXene structures. The flexibility to tune the structures allows for a thorough discussion of the relations between the morphology, electrical conductivity, and EMI shielding mechanism of the hybrids in a wide range of electrical conductivity (2.5 to 3347 S·cm-1) and thickness (7.7 to 1900 μm) values. The analysis of thin films shows the direct impact of the polymer content on the alignment and compactness of MXene nanosheets regulating the films' electrical conductivity/EMI shielding effectiveness. The colloidal behavior of the initial MXene suspension determines the interconnection of MXene nanosheets in MXene/PAH porous assemblies and the final electrical properties. In addition to the internal morphology, examining the laminated MXene/PAH fibers with geometrically different arrangements demonstrates the role of conductive network configuration on EMI shielding performance. These findings provide insights into tuning the EMI shielding effectiveness via the charge-driven bottom-up assembly of electrically conductive MXene/polyelectrolyte hybrids.

Utilization of hazardous red mud in silicone rubber/MWCNT nanocomposites for high performance electromagnetic interference shielding

With burgeoning technological advancement in telecommunication and high frequency electronics, its repercussion as electromagnetic pollution is alarmingly high. Hence, much effort has been made to supress this undesired phenomenon using efficient electromagnetic interference (EMI) shielding materials. Red mud, a hazardous by-product of alumina extraction is rich in oxides of iron, aluminium & titanium with ca. 30–60% of hematite, a magnetic lossy material that could be suitable for enhancing microwave absorption and EMI shielding performance of polymer nanocomposites. The impetus for this work was to utilize red mud as magnetically lossy filler in silicone rubber (SR)/multi-wall carbon nanotube (MWCNT) nanocomposites to function as efficient EMI shields with superior microwave absorption. Herein, taking the advantage of conductive percolated network of MWCNT in SR, red mud was incorporated with varying concentration of 5–20 wt% & compression moulded to form flexible sheets. These nanocomposite sheets exhibited a maximum electrical conductivity of 24 S/cm with superior EMI shielding effectiveness value of −83.4 dB in the X band (8.2–12.4 GHz) region making it a suitable candidate for commercial shielding applications. Moreover, sustainable use of a hazardous industrial waste to suppress EMI, which is yet another challenging invisible pollutant, is the key highlight of this work.

Transparent and Flexible Electromagnetic Interference Shielding Materials by Constructing Sandwich AgNW@MXene/Wood Composites.

Electromagnetic interference (EMI) shielding materials have attracted intensive attention with the increased electromagnetic pollution, which are required to possess high transparency and flexibility for applications in visualization windows, aerospace equipment, and wearable devices. However, it remains a challenge to achieve high-performance EMI shielding while maintaining excellent light transmittance. Herein, a sandwich composite is constructed by coating the core material of transparent wood (TW) with silver nanowire (AgNW)@MXene, exhibiting a maximum transmittance of 28.8% in the visible range and a longitudinal tensile strength of 47.8 MPa. The average EMI shielding effectiveness can reach up to 44.0 dB under X-band (8-12.4 GHz), ascribed to the increased absorption shielding induced by the multireflection of electromagnetic waves within microchannels of the TW layer and the interfacial polarization between AgNW and MXene. Simultaneously, large-scale EMI shielding films can be conveniently produced by our proposed method, which provides inspiration for the development of advanced EMI shielding materials for wide applications.

Electrically conductive and corrosion resistant MAX phases with superior electromagnetic wave shielding performance

MAX phases have emerged as promising corrosion-resistant electromagnetic interference (EMI) shielding materials. Herein, four MAX phases: Ti3SiC2, Ti3AlC2, V0.5Cr1.5AlC, and Nb4AlC3, were synthesized via solid–liquid reactions. The electrical conductivities of Ti3SiC2, Ti3AlC2, V0.5Cr1.5AlC, and Nb4AlC3 are 14.7 × 103, 15.5 × 103, 5.1 × 103, 8.0 × 103 S/cm, respectively, and the corresponding average EMI shielding effectiveness values in the frequency of 18–26.5 GHz are 53.9, 69.2, 19.4, and 29.0 dB, respectively. Most importantly, these MAX phases are highly corrosion resistant under acidic conditions. Despite the exposure to the acidic environment and a slight decrease in the electrical conductivity, the corroded MAX phases exhibited excellent EMI shielding properties compared to the pristine MAX phases. Additional analysis showed that reflection was the primary EMI blocking mechanism. The study offers a guide for designing MAX phase ceramics that exhibit high EMI shielding performance in corrosive environments.

Multifunctional CoFe2O4@MXene-AgNWs/Cellulose Nanofiber Composite Films with Asymmetric Layered Architecture for High-Efficiency Electromagnetic Interference Shielding and Remarkable Thermal Management Capability.

Developing high-efficiency electromagnetic interference (EMI) shielding composite films with outstanding flexibility and excellent thermal management capability is vital but challenging for modern integrated electronic devices. Herein, a facile two-step vacuum filtration method was used to fabricate ultrathin, flexible, and multifunctional cellulose nanofiber (CNF)-based composite films with an asymmetric layered architecture. The asymmetric layered structure is composed of a low-conductivity CoFe2O4@MXene/CNF layer and a highly conductive silver nanowires (AgNWs)/CNF layer. Benefiting from the rational placement of the impedance matching layer and shielding layer, as well as the synergistic effect of electric and magnetic losses, the resultant composite film exhibits an extremely high EMI shielding effectiveness (SE) of 73.3 dB and an average EMI SE of 70.9 dB with low reflected efficiency of 4.9 dB at only 0.1 mm thickness. Sufficiently reliable EMI SE (over 95% reservation) is attained even after suffering from continuous physical deformations and long-term chemical attacks. Moreover, the prepared films exhibit extraordinary flexibility, strong mechanical properties, and satisfactory thermal management capability. This work offers a viable strategy for exploiting high performance EMI shielding films with attractive thermal management capacity, and the resultant films present extensive application potential in aerospace, artificial intelligence, advanced electronics, stealth technology, and the national defense industry, even under harsh environments.

Flexible and High-Performance Electromagnetic Shielding Materials from Waste Polyurethane Foams

In the modern society, polymer composites utilizing various wastes for electromagnetic interference (EMI) shielding are of great economic and social significance. Herein, we report that waste polyurethane foams (WPUF) can be facilely converted into high-performance EMI shielding materials via surface coating of carbon nanotubes followed by hot pressing. The merit of this work lies in the novel skin-core segregated structure from the complete three-dimensional skeleton of WPUF, which is well retained after compression molding. The uniform distribution of multiwalled carbon nanotubes (MWCNTs) on the polyurethane skeleton surface assisted by cellulose nanofibers (CNFs) provides the material with remarkable electrical conductivity, leading to excellent EMI shielding properties. The resultant composite (WPUF-MC) achieves a high EMI shielding effectiveness (SE) of 63.2 dB at a low loading of MWCNTs (6.6 wt %), far surpassing the values for many early reported shielding materials of this kind. Moreover, the WPUF-MC also exhibits sufficient flexibility and reliable EMI shielding performance. Even if bent or twisted 1000 times, it can still maintain EMI SE at a fairly high level. This work not only offers an effective strategy for high-value utilization of WPUF but also may expand the application potential of flexible shielding materials.

Biomimetic Porous MXene Sediment-Based Hydrogel for High-Performance and Multifunctional Electromagnetic Interference Shielding.

Developing high-performance and functional hydrogels that mimic biological materials in nature is promising yet remains highly challenging. Through a facile, scalable unidirectional freezing followed by a salting-out approach, a type of hydrogels composed of "trashed" MXene sediment (MS) and biomimetic pores is manufactured. By integrating the honeycomb-like ordered porous structure, highly conductive MS, and water, the electromagnetic interference (EMI) shielding effectiveness is up to 90 dB in the X band and can reach more than 40 dB in the ultrabroadband gigahertz band (8.2-40 GHz) for the highly flexible hydrogel, outperforming previously reported porous EMI shields. Moreover, thanks to the stable framework of the MS-based hydrogel, the influences of water on shielding performance are quantitatively identified. Furthermore, the extremely low content of silver nanowire is embedded into the biomimetic hydrogels, leading to the significantly improved multiple reflection-induced microwave loss and thus EMI shielding performance. Last, the MS-based hydrogels allow sensitive and reliable detection of human motions and smart coding. This work thus not only achieves the control of EMI shielding performance via the interior porous structure of hydrogels, but also demonstrates a waste-free, low-cost, and scalable strategy to prepare multifunctional, high-performance MS-based biomimetic hydrogels.

Gradient structure silicone rubber composites for selective electromagnetic interference shielding enhancement and low reflection

Electromagnetic interference (EMI) shielding composites with gradient filler distributions were fabricated with the application of an induced magnetic field. The selective enrichment of nickel-coated carbon fibers within a core-shell structure effectively strengthens the overlap between fillers. This composite exhibited outstanding conductivities (98.2 S/m) that were two orders of magnitude greater than composites that possessed uniformly dispersed fillers because of the favorable inductive effect and the perfect loading of Ni nanoparticles. In addition, the sandwich structure causes the electromagnetic (EM) waves to reflect multiple times, further improving the EMI shielding effectiveness (SE) of the composite and resulting in a maximum SE of 60.8 dB. The introduction of magnetic Fe3O4@MWCNTs greatly increased the EM wave absorption efficiency from 14% to 45%, which resulted in low reflection peaks due to the resonant cancellation of the incident and reflected EM waves. The reflectivity of the composite was only 4% at 8.2 GHz, indicating a high absorption rate of 96% at this frequency. Furthermore, the composite shows excellent EMI shielding stability after 1000 repeated bends. This work thus describes a new approach to the preparation of high-performance (high-efficiency and low-reflectivity) EMI shielding materials and broadens their applicability to precision electronic devices and flexible wearable devices.

Methylene blue adsorption derived thermal insulating N, S-co-doped TiC/carbon hybrid aerogel for high-efficient absorption-dominant electromagnetic interference shielding

The development of absorption-dominant electromagnetic interference (EMI) shielding materials with high-efficiency EMI shielding effectiveness (SE) and low reflection (R) is crucial but challenging for next-generation electronics devices and telecommunication. In this regard, a facile and environmentally friendly approach was proposed to fabricate N, S-co-doped TiC/carbon hybrid aerogels with hierarchically porous architecture through MXene/cellulose hybrid hydrogels as precursors for adsorbing dyes, followed by freeze drying and carbonization process. Profiting from the synergistic effect of highly interconnected three-dimensional (3D) porous structure, heterogeneous conductive network with greatly conductive difference as well as heteroatoms-doping induced dipole polarization, the resultant aerogel with an ultra-low density (47.1 mg/cm3) achieves a highly efficient EMI SE of 84.3 dB at 12.4 GHz (average 81.8 dB in the X-band) and a superior absorption coefficient of 0.68 simultaneously. Meanwhile, the highly porous structure endows the prepared aerogels with outstanding thermal insulating capacity, which is essential to provide infrared stealth and radar stealth for military equipment and to protect sensitive electronic devices from high-temperature attacks. This work offers a prospective strategy for constructing high-performance absorption-dominated EMI shielding materials with excellent thermal insulation properties, and the obtained aerogels present broad application prospects in the fields of aviation, portable electronic equipment and national defense industry.

Multifunctional MXene/Aramid Nanofiber Composite Films for Efficient Electromagnetic Interference Shielding and Repeatable Early Fire Detection.

Rapid development of highly integrated electronic and telecommunication devices has led to urgent demands for electromagnetic interference (EMI) shielding materials that incorporate flame retardancy, and more desirably the early fire detection ability, due to the potential fire hazards caused by heat propagation and thermal failure of the devices during operation. Here, multifunctional flexible films having the main dual functions of high EMI shielding performance and repeatable fire detection ability are fabricated by vacuum filtration of the mixture of MXene and aramid nanofiber (ANF) suspensions. ANFs serve to reinforce MXene films via the formation of hydrogen bonding between the carbonyl groups of ANFs and the hydroxyl groups of MXene. When the ANF content is 20 wt %, the tensile strength of the film is increased from 24.6 MPa for a pure MXene film to 79.5 MPa, and such a composite film (9 μm thickness) exhibits a high EMI shielding effectiveness (SE) value of ∼40 dB and a specific SE (SSE) value of 4361.1 dB/mm. Upon fire exposure, the composite films can trigger the fire detection system within 10 s owing to the thermoelectric property of MXene. The self-extinguishing feature of ANFs ensures the structural integrity of the films during burning, thus allowing for continuous alarm signals. Moreover, the films also exhibit excellent Joule heating and photothermal conversion performances with rapid response and sufficient heating reliability.

Ultra-compact MXene fibers by continuous and controllable synergy of interfacial interactions and thermal drawing-induced stresses

Recent advances in MXene (Ti3C2Tx) fibers, prepared from electrically conductive and mechanically strong MXene nanosheets, address the increasing demand of emerging yet promising electrode materials for the development of textile-based devices and beyond. However, to reveal the full potential of MXene fibers, reaching a balance between electrical conductivity and mechanical property is still the fundamental challenge, mainly due to the difficulties to further compact the loose MXene nanosheets. In this work, we demonstrate a continuous and controllable route to fabricate ultra-compact MXene fibers with an in-situ generated protective layer via the synergy of interfacial interactions and thermal drawing-induced stresses. The resulting ultra-compact MXene fibers with high orientation and low porosity exhibit not only excellent tensile strength and ultra-high toughness, but also high electrical conductivity. Then, we construct meter-scale MXene textiles using these ultra-compact fibers to achieve high-performance electromagnetic interference shielding and personal thermal management, accompanied by the high mechanical durability and stability even after multiple washing cycles. The demonstrated generic strategy can be applied to a broad range of nanostructured materials to construct functional fibers for large-scale applications in both space and daily lives.

Rheology-Guided Assembly of a Highly Aligned MXene/Cellulose Nanofiber Composite Film for High-Performance Electromagnetic Interference Shielding and Infrared Stealth.

Delicately aligned structures of two-dimensional (2D) MXene nanosheets have demonstrated positive effects on applications, especially in electromagnetic interference (EMI) shielding and infrared (IR) stealth. However, precise regulation of structural assembly by theory-guided solution processing is still a great challenge. Herein, one-dimensional (1D) cellulose nanofibers (CNFs) with a high aspect ratio are applied as a reinforcing agent and a rheological modifier for MXene/CNF colloids to fabricate aligned MXene-based materials for EMI shielding and IR stealth. Notably, a systematical rheological study of the MXene/CNF colloids is proposed to determine the optimal solution-processing conditions for finely oriented component arrangement requirements and provides in-depth information on the interactions between the components. The delicately regulated orientation structure assembled by shear inducement is convincingly demonstrated through micro-CT and wide-angle X-ray diffraction/small-angle X-ray scattering (WAXD/SAXS), which endows the MXene/CNF film with a significantly enhanced electrical conductivity of 46 685 S m-1, a tensile strength of 281.7 MPa, and Young's modulus of 14.8 GPa. Furthermore, the highly aligned structure of the ultrathin film possesses a great enhancement in EMI shielding effectiveness (50.2 dB) and IR stealth (0.562 emissivity). These findings provide a fruitful understanding of the optimized fabrication in solution processing of high-performance MXene-based functional composite films and open up a great opportunity for the development of multifunctional stealth materials.

Flexible aramid nanofiber/Ag nanowires/graphene nanosheets composite films with sandwich structure for high-performance electromagnetic interference shielding and Joule heating

Multifunctional materials have attracted tremendous attention owing to their applications in military, healthcare and medical therapy, intelligent and wearable devices. Herein, multifunctional sandwich structure composite film consisting with aramid nanofiber (ANF), silver nanowires (AgNWs) and graphene nanosheets (GNs) is fabricated via a facile vacuum filtration following a hot-pressing method, which is applied in electromagnetic interference (EMI) shielding and Joule heating. ANF/AgNWs/GNs (AAG) sandwich structure composite film not only realizes excellent EMI shielding performance but also possesses outstanding Joule heating property due to with high electrical conductivity owing to AgNWs network layer. EMI shielding and Joule heating performance of AAG composite films are gradually enhanced with increasing the mass ratio of AgNWs, which can be attributed to the increase of electrical conductivity. When the mass of AgNWs is increased to 30 mg, AAG-24 g m−2 composite film with thickness of 40 µm displays a superior EMI shielding effectiveness of 68.3 dB and specific shielding effectiveness of 16,545.4 dB cm−2 g−1. In addition, the surface temperature of AAG-24 g m−2 film reaches approximately 133 °C at a low working voltage of 3.0 V. This work introduces that the multifunctional sandwich structure composite films with an excellent EMI shielding and Joule heating performance have a huge potential application for numerous actual fields.

Tunable high-performance electromagnetic interference shielding of intrinsic N-doped chitin-based carbon aerogel

Heteroatom doping of carbon aerogels is a promising strategy to dissipate electromagnetic waves (EMWs) and it is still a daunting challenge to establish the relationship between heteroatomic structure and EMI shielding performance. In our work, intrinsic N-doped biomass-based carbon aerogel was successfully prepared by freeze-drying and a specific two-stage pyrolysis using chitin and chitosan as carbon and nitrogen source. The content and type of doping elements and electrical conductivity could be accurately manipulated by controlling the content of precursors and carbonization temperature. The intrinsic N-doped induced a dipole polarization, and the unique three-dimensional porous architecture of biomass-based carbon aerogel was conducive to multiple reflection/scattering of EMWs. The as-prepared biomass-based carbon aerogel at 1300 °C exhibited an optimal EMI performance of 82 dB, and the absorption coefficients could be tuned in the range of 0.31–0.88. The excellent EMI performance originated from a variety of mechanisms involving conduction loss, dipole polarization loss, and interface polarization loss. The novel heteroatomic doping strategy not only provides new insight into the contribution of heteroatomic structure to EMI shielding performance, but also opens a new avenue to develop biomass-based carbon aerogels with tunable EMI shielding performances.

Promising PVDF-CNT-Graphene-NiCo chains composite films with excellent electromagnetic interference shielding performance

Polymer-based composite electromagnetic interference (EMI) shielding materials have aroused great interest among scientific researchers because of excellent properties. Herein, the poly(vinylidene fluoride) (PVDF)-carbon nanotube (CNT)-Graphene (G)-NiCo chains composite film with ultrahigh EMI shielding properties was prepared through solution mixing and compression molding. In the composite film, 1D carbon nanotube (CNT) and NiCo chains connected the surrounding 2D graphene nanoplates and formed interfacial interconnected networks. The electrical conductivity and total electromagnetic interference shielding effectiveness (EMI SE T ) of the samples increased progressively with the increased NiCo quality contents. The resultant PVDF-CNT-G-8NiCo composite film exhibited an excellent electrical conductivity of 9.12 S/cm and an ultrahigh EMI SE T of 63.3 dB. The results were superior to those of PVDF-CNT-8NiCo composite film, clearly confirming the synergistic effect of graphene nanoplates and CNT. The formation of multi-layers interfacial conductive CNT-G-NiCo networks promoted conductive dissipation, multiple reflections and scattering of incident electromagnetic (EM) waves. Meanwhile, this work provides guidance for the rational design of high-performance polymer-based composite EMI shielding materials and has great potential in practical applications. • PVDF-CNT-Graphene-NiCo chains composite film was prepared. • The synergistic effect of CNT, graphene and NiCo alloy formed interconnected networks. • The multi-layers networks promoted conductive dissipation, and multiple scattering of EM waves. • A superior EMI SE T of 63.3 dB were achieved in PVDF-CNT-G-8NiCo composite film.