Graphite Nanosheet-Based Carbon Foams for Electromagnetic Interference Shielding

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.