Absorption-dominated electromagnetic shielding and excellent thermal conduction properties of poly(vinylidene fluoride)/SnBi58/Co-C composites with layered structure

Abstract

Electromagnetic interference (EMI) shielding materials with low reflection and excellent thermal conduction are vitally important for sophisticated devices and next-generation communications technologies. This work offers a feasible strategy to develop multifunction absorption-dominated shielding materials by constructing layered structure with bicontinuous interpenetrating networks. Magnetic Co-C particles derived from metals metal–organic frameworks are introduced to serve as a microwave absorber that endows the system with strong absorption in the upper layer. While, low-melting-point alloys (LMPAs) at the bottom can form a perfect conductive network, providing sufficient microwave reflection for the composites. This special structure can bring a distinctive “absorb-reflect-reabsorb” process while waves penetrate into the sample, leading to a high EMI shielding effectiveness (SE) with a low power coefficient of reflectivity (R). The composites with Co-C(20 wt%) and LMPAs(30 vol%) achieves an average EMI SE of ~50 dB, while R is ~0.40. In particular, benefitting from the alloy network, the thermal conductivity of the lower layer is greatly improved from ~0.22 W/mK to ~1.50 W/mK. With integrating these remarkable features in one material, this layered structure composite might be more competitive in many application fields such as 5 G communications and green building.