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HighlightsDetailed summary of current trends in the advancement of flexible EMI shielding materials.The theoretical shielding mechanisms and the latest concept of \"green shielding\" index (gs) are outlined.Functional applications of flexible EMI shielding materials are introduced from thermal conductivity, hydrophobicity to transparency, sensing even multiple functions.Exclusive insights in challenges and future design strategies opportunities for flexible EMI shielding materials are provided.With rapid development of 5G communication technologies, electromagnetic interference (EMI) shielding for electronic devices has become an urgent demand in recent years, where the development of corresponding EMI shielding materials against detrimental electromagnetic radiation plays an essential role. Meanwhile, the EMI shielding materials with high flexibility and functional integrity are highly demanded for emerging shielding applications. Hitherto, a variety of flexible EMI shielding materials with lightweight and multifunctionalities have been developed. In this review, we not only introduce the recent development of flexible EMI shielding materials, but also elaborate the EMI shielding mechanisms and the index for \"green EMI shielding\" performance. In addition, the construction strategies for sophisticated multifunctionalities of flexible shielding materials are summarized. Finally, we propose several possible research directions for flexible EMI shielding materials in near future, which could be inspirational to the fast-growing next-generation flexible electronic devices with reliable and multipurpose protections as offered by EMI shielding materials.

High-performance electromagnetic wave absorption and electromagnetic interference (EMI) shielding materials with multifunctional characters have attracted extensive scientific and technological interest, but they remain a huge challenge. Here, we reported an electrostatic assembly approach for fabricating 2D/1D/0D construction of Ti3C2Tx/carbon nanotubes/Co nanoparticles (Ti3C2Tx/CNTs/Co) nanocomposites with an excellent electromagnetic wave absorption, EMI shielding efficiency, flexibility, hydrophobicity, and photothermal conversion performance. As expected, a strong reflection loss of -85.8 dB and an ultrathin thickness of 1.4 mm were achieved. Meanwhile, the high EMI shielding efficiency reached 110.1 dB. The excellent electromagnetic wave absorption and shielding performances were originated from the charge carriers, electric/magnetic dipole polarization, interfacial polarization, natural resonance, and multiple internal reflections. Moreover, a thin layer of polydimethylsiloxane rendered the hydrophilic hierarchical Ti3C2Tx/CNTs/Co hydrophobic, which can prevent the degradation/oxidation of the MXene in high humidity condition. Interestingly, the Ti3C2Tx/CNTs/Co film exhibited a remarkable photothermal conversion performance with high thermal cycle stability and tenability. Thus, the multifunctional Ti3C2Tx/CNTs/Co nanocomposites possessing a unique blend of outstanding electromagnetic wave absorption and EMI shielding, light-driven heating performance, and flexible water-resistant features were highly promising for the next-generation intelligent electromagnetic attenuation system.HighlightsThe 2D/1D/0D Ti3C2Tx/carbon nanotubes/Co nanocomposite is successfully synthesized via an electrostatic assembly.Nanocomposites exhibit an excellent electromagnetic wave absorption and a remarkable electromagnetic interference shielding efficiency.The flexible, waterproof, and photothermal conversion performances are achieved.

HighlightsThe squid pen-derived aerogel with intrinsic electropositivity is prepared to electrostatically assemble carbon nano-onion with low escape energy.Under the guidance of PNM model, the interface polarization is reinforced from the aspect of porous skeleton, nanomaterials and multilayer construction.Benefiting from boosted Maxwell-Wagner-Sillars effect, the aerogel and film display remarkable electromagnetic wave absorption (−50.83 dB) and electromagnetic interference shielding performance (66.66 dB), respectively.The rational construction of microstructure and composition with enhanced Maxwell-Wagner-Sillars effect (MWSE) is still a challenging direction for reinforcing electromagnetic wave (EMW) absorption performance, and the related EMW attenuation mechanism has rarely been elucidated. Herein, MWSE boosted β-chitin/carbon nano-onions/Ni–P composites is prepared according to the heterointerface engineering strategy via facile layer-by-layer electrostatic assembly and electroless plating techniques. The heterogeneous interface is reinforced from the aspect of porous skeleton, nanomaterials and multilayer construction. The composites exhibit competitive EMW response mechanism between the conductive loss and the polarization/magnetic loss, as describing like the story of “The Hare and the Tortoise”. As a result, the composites not only achieve a minimum reflection loss (RLmin) of − 50.83 dB and an effective bandwidth of 6.8 GHz, but also present remarkable EMW interference shielding effectiveness of 66.66 dB. In addition, diverse functions such as good thermal insulation, infrared shielding and photothermal performance were also achieved in the hybrid composites as a result of intrinsic morphology and chemicophysics properties. Therefore, we believe that the boosted MWSE open up a novel orientation toward developing multifunctional composites with high-efficient EMW response and thermal management.

Nuclear energy offers a wide range of applications, which include power generation, X-ray imaging, and non-destructive tests, in many economic sectors. However, such applications come with the risk of harmful radiation, thereby requiring shielding to prevent harmful effects on the surrounding environment and users. Concrete has long been used as part of structures in nuclear power plants, X-ray imaging rooms, and radioactive storage. The direction of recent research is headed toward concrete’s ability in attenuating harmful energy radiated from nuclear sources through various alterations to its composition. Radiation shielding concrete (RSC) is a composite-based concrete that was developed in the last few years with heavy natural aggregates such as magnetite or barites. RSC is deemed a superior alternative to many types of traditional normal concrete in terms of shielding against the harmful radiation, and being economical and moldable. Given the merits of RSCs, this article presents a comprehensive review on the subject, considering the classifications, alternative materials, design additives, and type of heavy aggregates used. This literature review also provides critical reviews on RSC performance in terms of radiation shielding characteristics, mechanical strength, and durability. In addition, this work extensively reviews the trends of development research toward a broad understanding of the application possibilities of RSC as an advanced concrete product for producing a robust and green concrete composite for the construction of radiation shielding facilities as a better solution for protection from sources of radiation. Furthermore, this critical review provides a view of the progress made on RSCs and proposes avenues for future research on this hotspot research topic.

HighlightsThis work proposes a tactic for improving the efficiency of thermal energy conversion and expanding the application scenarios of phase change materials by constructing non-binder and oriented MXene-K+ aerogel.The prepared phase change composites (PCCs) can rapidly transform solar, electric, magnetic energy into latent heat for keeping warm, power generation, and thermal physiotherapy.Owing to the suggested tactic, the prepared PCCs achieves ultrahigh energy storage density and realize 99.9998% electromagnetic wave energy attenuation.The severe dependence of traditional phase change materials (PCMs) on the temperature-response and lattice deficiencies in versatility cannot satisfy demand for using such materials in complex application scenarios. Here, we introduced metal ions to induce the self-assembly of MXene nanosheets and achieve their ordered arrangement by combining suction filtration and rapid freezing. Subsequently, a series of MXene/ K+/paraffin wax (PW) phase change composites (PCCs) were obtained via vacuum impregnation in molten PW. The prepared MXene-based PCCs showed versatile applications from macroscale technologies, successfully transforming solar, electric, and magnetic energy into thermal energy stored as latent heat in the PCCs. Moreover, due to the absence of binder in the MXene-based aerogel, MK3@PW exhibits a prime solar–thermal conversion efficiency (98.4%). Notably, MK3@PW can further convert the collected heat energy into electric energy through thermoelectric equipment and realize favorable solar–thermal–electric conversion (producing 206 mV of voltage with light radiation intensity of 200 mw cm−2). An excellent Joule heat performance (reaching 105 °C with an input voltage of 2.5 V) and responsive magnetic–thermal conversion behavior (a charging time of 11.8 s can achieve a thermal insulation effect of 285 s) for contactless thermotherapy were also demonstrated by the MK3@PW. Specifically, as a result of the ordered arrangement of MXene nanosheet self-assembly induced by potassium ions, MK3@PW PCC exhibits a higher electromagnetic shielding efficiency value (57.7 dB) than pure MXene aerogel/PW PCC (29.8 dB) with the same MXene mass. This work presents an opportunity for the multi-scene response and practical application of PCMs that satisfy demand of next-generation multifunctional PCCs.

HighlightsThe rGO/CoNi nanosheets embedded between the MXene layers can continue to serve as a conductive channel, ensuring carrier migration and proper conductive loss capability.Owing to the strong magnetic coupling between the magnetic FeCo alloy nanoparticles on the rGO substrate, the entire MXene-rGO/CoNi film exhibits a strong magnetic loss capability.Self-assembly MXene-rGO/CoNi films hold excellent microwave absorption performance − 54.1 dB at 13.28 GHz.MXene, as a rising star of two-dimensional (2D) materials, has been widely applied in fields of microwave absorption and electromagnetic shielding to cope with the arrival of the 5G era. However, challenges arise due to the excessively high permittivity and the difficulty of surface modification of few-layered MXenes severely, which infect the microwave absorption performance. Herein, for the first time, a carefully designed and optimized electrostatic self-assembly strategy to fabricate magnetized MXene-rGO/CoNi film was reported. Inside the synthesized composite film, rGO nanosheets decorated with highly dispersed CoNi nanoparticles are interclacted into MXene layers, which effectively suppresses the originally self-restacked of MXene nanosheets, resulting in a reduction of high permittivity. In addition, owing to the strong magnetic coupling between the magnetic FeCo alloy nanoparticles on the rGO substrate, the entire MXene-rGO/CoNi film exhibits a strong magnetic loss capability. Moreover, the local dielectric polarized fields exist at the continuous hetero-interfaces between 2D MXene and rGO further improve the capacity of microwave loss. Hence, the synthesized composite film exhibits excellent microwave absorption property with a maximum reflection loss value of − 54.1 dB at 13.28 GHz. The electromagnetic synergy strategy is expected to guide future exploration of high-efficiency MXene-based microwave absorption materials.

As space missions become increasingly complex, protection against high-energy charged particles has emerged as a critical factor for the safe operation of spacecraft. These electrical particles, including protons and electrons, can penetrate spacecraft structures and cause severe damage to internal components. Therefore, this review discusses the characteristics of the high-energy charged particle environment in Earth orbits. Accordingly, various passive shielding materials have been evaluated, highlighting their advantages, disadvantages, and applicability in different orbital environments. Specifically, the importance of optimizing shielding materials and structures to enhance the radiation resistance of spacecraft has been emphasized. Furthermore, advancements in passive shielding materials for high-energy charged particles in Earth orbit over the past few years have been examined. Finally, future research directions have been proposed, including the development of lighter and more efficient shielding materials, the optimization of multi-layer shielding structures, and the integration of passive shielding with other protective technologies.

HighlightsCarbon nanotubes/polymerizable ionic liquid copolymer (CNTs/PIL) provides nucleation sites and inhibits the combination of microcellular structures.The increase in evaporate time improves the conductive network of composite foams.Electromagnetic interference shielding effectiveness (EMI SE) and specific EMI SE of the composite foam displays 69.9 dB and 211.5 dB/(g cm−3).Polarization, conduction and magnetic loss attenuate microwave energy.Lightweight microcellular polyurethane (TPU)/carbon nanotubes (CNTs)/ nickel-coated CNTs (Ni@CNTs)/polymerizable ionic liquid copolymer (PIL) composite foams are prepared by non-solvent induced phase separation (NIPS). CNTs and Ni@CNTs modified by PIL provide more heterogeneous nucleation sites and inhibit the aggregation and combination of microcellular structure. Compared with TPU/CNTs, the TPU/CNTs/PIL and TPU/CNTs/Ni@CNTs/PIL composite foams with smaller microcellular structures have a high electromagnetic interference shielding effectiveness (EMI SE). The evaporate time regulates the microcellular structure, improves the conductive network of composite foams and reduces the microcellular size, which strengthens the multiple reflections of electromagnetic wave. The TPU/10CNTs/10Ni@CNTs/PIL foam exhibits slightly higher SE values (69.9 dB) compared with TPU/20CNTs/PIL foam (53.3 dB). The highest specific EMI SE of TPU/20CNTs/PIL and TPU/10CNTs/10Ni@CNTs/PIL reaches up to 187.2 and 211.5 dB/(g cm−3), respectively. The polarization losses caused by interfacial polarization between TPU substrates and conductive fillers, conduction loss caused by conductive network of fillers and magnetic loss caused by Ni@CNT synergistically attenuate the microwave energy.

HighlightsThe review discusses the key concepts, loss mechanisms and test methods of electromagnetic interference (EMI) shielding.The research progress of polymer matrix EMI shielding composites with different structures is detailedly illustrated, especially their preparation methods and corresponding evaluations.The key scientific and technical problems for polymer matrix EMI shielding composites with different structures are proposed, and their development trend are prospected.With the widespread application of electronic communication technology, the resulting electromagnetic radiation pollution has been significantly increased. Metal matrix electromagnetic interference (EMI) shielding materials have disadvantages such as high density, easy corrosion, difficult processing and high price, etc. Polymer matrix EMI shielding composites possess light weight, corrosion resistance and easy processing. However, the current polymer matrix composites present relatively low electrical conductivity and poor EMI shielding performance. This review firstly discusses the key concept, loss mechanism and test method of EMI shielding. Then the current development status of EMI shielding materials is summarized, and the research progress of polymer matrix EMI shielding composites with different structures is illustrated, especially for their preparation methods and evaluation. Finally, the corresponding key scientific and technical problems are proposed, and their development trend is also prospected.

HighlightsA multifunctional Janus film is fabricated by integrating highly-crystalline and oxidation-resistant Ti3C2Tx MXene with carbon nanotube (CNT) film through strong hydrogen bonding, which exhibits high electrical conductivity of 4250 S cm−1 and robust mechanical strength of 77 MPa.The MXene/CNT Janus film of 15 μm thickness demonstrates efficient electromagnetic interference shielding of 72 dB, low infrared (IR) emissivity of 0.09 and hence superior thermal camouflage performance, and outstanding IR detection capability, while maintaining its integrity equally at room temperature as well as under extreme conditions.This multifunctional MXene/CNT Janus film offers a practical solution for electromagnetic shielding and IR shielding/detection in challenging conditions.Multifunctional, flexible, and robust thin films capable of operating in demanding harsh temperature environments are crucial for various cutting-edge applications. This study presents a multifunctional Janus film integrating highly-crystalline Ti3C2Tx MXene and mechanically-robust carbon nanotube (CNT) film through strong hydrogen bonding. The hybrid film not only exhibits high electrical conductivity (4250 S cm−1), but also demonstrates robust mechanical strength and durability in both extremely low and high temperature environments, showing exceptional resistance to thermal shock. This hybrid Janus film of 15 μm thickness reveals remarkable multifunctionality, including efficient electromagnetic shielding effectiveness of 72 dB in X band frequency range, excellent infrared (IR) shielding capability with an average emissivity of 0.09 (a minimal value of 0.02), superior thermal camouflage performance over a wide temperature range (− 1 to 300 °C) achieving a notable reduction in the radiated temperature by 243 °C against a background temperature of 300 °C, and outstanding IR detection capability characterized by a 44% increase in resistance when exposed to 250 W IR radiation. This multifunctional MXene/CNT Janus film offers a feasible solution for electromagnetic shielding and IR shielding/detection under challenging conditions.