Ultrathin Densified Carbon Nanotube Film with “Metal-like” Conductivity, Superior Mechanical Strength, and Ultrahigh Electromagnetic Interference Shielding Effectiveness

Abstract

Flexible and lightweight high-performance electromagnetic interference shielding materials with minimal thickness, excellent mechanical properties, and outstanding reliability are highly desired in the field of fifth-generation (5G) communication, yet remain extremely challenging to manufacture. Herein, we prepared an ultrathin densified carbon nanotube (CNT) film with superior mechanical properties and ultrahigh shielding effectiveness. Upon complete removal of impurities in pristine CNT film, charge separation in individual CNTs induced by polar molecules leads to strong CNT–CNT attraction and film densification, which significantly improve the electrical conductivity, shielding performance, and mechanical strength. The tensile strength is up to 822 ± 21 MPa, meanwhile the electrical conductivity is as high as 902,712 S/m, and the density is only 1.39 g cm–3. Notably, the shielding effectiveness is over 51 dB with a thickness of merely 1.85 μm in the broad frequency range of 4–18 GHz, and it reaches to ∼82 dB at 6.36 μm and ∼101 dB at 14.7 μm, respectively. Further, such CNT film exhibits excellent reliability after an extended period in strong acid/alkali, high temperature, and high humidity. It demonstrates the best overall performance among representative shielding materials by far, representing a critical breakthrough in the preparation of shielding film toward applications in wearable electronics and 5G communication.

Tailorable, Lightweight and Superelastic Liquid Metal Monoliths for Multifunctional Electromagnetic Interference Shielding

“…As we know, the high-frequency electromagnetic waves will attenuate faster in the medium due to their shorter wavelength results in a closer distance between the troughs and crests. The greater difference in the electric field near a certain point of the medium causes the increasing current, therefore, the more electromagnetic waves energy is attenuated in the medium upon increasing frequency [ 6 , 51 ]. EMI shielding mechanism analysis can also verify this trend.…”

EMI Shielding Nanocomposite Laminates with High Temperature Resistance, Hydrophobicity and Anticorrosion Properties

“…To further analyze the EMI shielding mechanism of the as-fabricated CEC composites, the corresponding power coefficients of reflectivity (R), absorptivity (A), and transmission coefficient (T) were employed to evaluate the power balance of electromagnetic waves interacting with materials. As depicted in Figure 2, R is always higher than A although SE R is smaller than SE A regardless of the preparation methods, implying primary shielding mechanism of reflection loss [20][21][22][23].…”

“…To further analyze the EMI shielding mechanism of the as-fabricated CEC composites, the corresponding power coefficients of reflectivity (R), absorptivity (A), and transmission coefficient (T) were employed to evaluate the power balance of electromagnetic waves interacting with materials. As depicted in Figure 2, R is always higher than A although SER is smaller than SEA regardless of the preparation methods, implying primary shielding mechanism of reflection loss [20][21][22][23]. To verify the influence of structures on the EMI shielding properties of the CEC materials, EMI shielding properties of materials manufactured by CNTF e-heating containing differing numbers of composite prepregs and CNTFs were investigated.…”

Design and Synthesis Strategies: 2D Materials for Electromagnetic Shielding/Absorbing

“…reported a novel film structure that was formed by 2D titanium carbide ink and it exhibited excellent EMI SE of 50 dB at 1.35 μm. An ultrathin dense carbon nanotube (CNT) film exhibited ultrahigh EMI SE of more than 51 dB (4 GHz∼18 GHz) with the thickness of 1.85 μm [35] . As for MA, microstructures with regular cavities, porous structures, and rich interfaces are more necessary.…”