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 lowconductivity CoFe 2 O 4 @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.

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Developing highly efficient electromagnetic interference (EMI) shielding materials with outstanding mechanical properties are urgently desirable for portable device hardware and flexible electronic devices. Herein, a highly conductive and flexible silver nanowires/graphene nanosheets/cellulose (AgNWs/GNSs/cellulose) composite paper with particular three‐layered structures is fabricated via vacuum assisted filtered and coating method. The prepared composites exhibit excellent EMI shielding property due to the unique layered structure. By changing the order of the conductive layers, the overall shielding performance can be further improved. An outstanding EMI shielding effectiveness (SE) of 53.3 dB is achieved with a thickness of only 0.17 mm. The composites show prominent bending resistance, which is proved by 1000 times of repeated bending leading to no obvious changes in structure. Moreover, the prepared composites exhibit excellent mechanical properties. Therefore, it is expected that this work will open up a facile strategy for exploiting materials with excellent EMI shielding properties and mechanical performance.

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Carbon fibrous (CF) membranes were fabricated by electrospinning, thermal stabilization, and the carbonization process. The in-depth analyses of the CF membranes’ composition, structure, and microwave absorption (MA) property demonstrate that the MA performance of the membranes is strongly correlated with the C/O ratio and CF framework's microstructure. A maximum absorption value of −23.4 dB is achieved at 800 °C, and this was synergistically enhanced to −42.5 dB with the addition of graphene nanosheets (GNSs). The special multilayered membranes containing dielectric loss CNSs and CFs making the balance between excellent impedance matching and the high loss characteristic could deliver an excellent MA property. With the facile and controllable synthesis of the GNS/CF membranes, a new approach to efficiently optimize and regulate its MA behavior is now possible.