Graphite Nanosheet-Based Carbon Foams for Electromagnetic Interference Shielding

Abstract

Fabrication of low-cost, lightweight, and flexible materials with high performance for electromagnetic interference (EMI) shielding is a great challenge in practical application. Alleviating “secondary pollution” by improving adsorption loss is of great significance to preventing electronic instruments from EMI and protecting human health. In this paper, a three-dimensional porous carbon foam (PCF) with low density (0.089 g/cm–3), high conductivity (1.5 × 105 S/m), high flexibility, and excellent shielding effectiveness (SE) was fabricated by immersing the expanded graphite(ene) film (EGF) into liquid nitrogen followed by the evaporation treatment. The SE of the PCF was about 137 dB at 0.03–1 GHz at a thickness of 2.8 mm, and the adsorption loss (SEA) can be up to as high as 122 dB. The excellent SE of the PCF is mainly attributed to the rich cellular porous structure, which leads to electromagnetic wave energy eventually being converted into heat energy inside the PCF by adsorption loss and dissipation. Furthermore, the PCF exhibits excellent performance of thermal discharge such that the temperature drops from 203 to 38 °C within 15 s. This research will provide an effective path to obtain a lightweight and flexible EMI shielding material that can reduce secondary pollution of electromagnetic radiation.

Ti3C2Tx MXene Nanosheet/Cellulose Nanofiber/Poly(ethylene glycol) Porous Composites for Absorption-Dominated Electromagnetic Interference Shielding

“…The dielectric loss provided by MXene and the coordination of polarization with loss at the interfaces contribute to the outstanding EMI shielding effectiveness (EMI SE) (39 dB) and absorption effectiveness (28 dB) of the films. However, due to the high conductivity of its surface, similar electromagnetic shielding materials are reflection-based and will produce a strong reflection of electromagnetic waves, and do not fundamentally eliminate electromagnetic waves, the existence of reflected electromagnetic waves will still cause secondary pollution of electromagnetic waves. − Considering these problems, materials with absorption-dominated electromagnetic shielding have been widely studied recently. , …”

Bacterial-Cellulose-Reinforced Graphite Nanoplate Films for Electromagnetic Interference Shielding, Heat Conduction, and Joule Heating

“…With the flourishing development of wireless communication, the miniaturization and integration of electronic equipment have caused overheating and electromagnetic interference (EMI) pollution, which not only affects the function of devices but also threatens human health. Therefore, there is an urgent need for materials with excellent EMI shielding and thermal conductivity (TC) performances simultaneously to address the above issues. − Conductive polymer composites (CPCs) are under extensive study because of their lightweight, flexibility, and corrosion resistance. , The commonly used conductive fillers in CPCs include metal, − carbon nanotubes (CNT), − graphene, − transition metal carbide/carbonitride (MXene), − etc. For instance, Gu and Feng et al prepared EMI shielding materials with good TC properties using silver nanowires (AgNWs) and MXene, ,, but the high cost and easy oxidation of AgNWs and MXene limit their wide application.…”

Electrical and electromagnetic shielding properties of thermally-stable polybenzoxazine/expanded graphite nanocomposites

“…[2][3][4][5][6] Expanded graphite (EG) has an electrical conductivity of about 10 4 S.cm À1 and an EMI shielding of nearly 130 dB for its compressed sheet, so it has been extensively researched as a conductive filler for various polymer matrices. [7][8][9] The percolation threshold for EGmediated polymer nanocomposites was reported to range between 0.05 and 2.5 vol.%. [10][11][12] The increased aspect ratio, honeycomb morphology, and large surface area of EG are attributed to the lower percolation threshold and excellent mechanical properties of the studied polymer/ EG nanocomposites.…”