Highly conductive and flexible electromagnetic shielding film obtained by molding an expanded graphite/silver/sodium alginate aerogel

The development of flexible, thin and excellent electromagnetic interference (EMI) shielding performance polymer-based materials is a powerful means to solve electromagnetic pollution. However, traditional methods for preparing light and thin materials, such as vacuum-assisted filtration and pouring molding method, still have shortcomings. Here, we innovatively developed a green, sustainable, large-scale “sol-gel-compression” film-forming technology and obtained flexible EG/AgNPs/SA composite film with a thickness of only 0.16 mm, high electrical conductivity (12,600 S/m), and supreme electromagnetic interference (EMI) shielding efficiency (40.1 dB). The preparation technology is simple to operate, and at the same time, the molding effect effectively promotes the formation of the conductive network and takes into account the thickness and flexibility of the material. Owing to the ultrahigh conductivity, superior EMI shielding efficiency, and flexibility, the EG/AgNPs/SA composite films present significant advantages over other carbon-polymer materials and demonstrate considerable application potential in electromagnetic protection fields such as the communications industry, artificial intelligence, and wearable electronics. • “Sol-gel-compression” film-forming technology was innovatively developed to prepare sustainable, large-scale composite film • EG/AgNPs/SA composite film (thickness, 0.16 mm, conductivity, 1.26*10 4 S/m) achieved supreme EMI SE of 40.1 dB • “Nacre-like” layered structure was constructed to study the effect on EMI performance and interaction among the components