3D Expanded Graphite Frameworks for Dual-Functional Polymer Composites with Exceptional Thermal Conductive and Electromagnetic Interference Shielding Capabilities

At present, dual-functional polymer composites possessing excellent thermal conductivity and high electromagnetic interference shielding effectiveness (EMI SE) are largely demanded in the synchronous thermal and EM wave management of advanced microelectronic devices. Herein, we report an annealed 3D expanded graphite (A-3D-EG) framework featuring high-quality continuous carbon architectures that can serve as high-throughput phonon and electron transmission pathways to effectively elevate the thermal conductivity and EMI shielding performance of polymers. This framework is fabricated via hydrothermally treating the aqueous slurry containing EG and GO fillers, followed by freezing-drying and annealing treatment at 1600 °C for 2 h. As a result, the polydimethylsiloxane composite filled with A-3D-EG reveals an outstanding thermal conductivity of 12.95 Wm–1K–1 and a high EMI SE of 85.0 dB at a low filler content of 31.9 wt %. This work demonstrates that A-3D-EG has enormous utilization potential in fabricating polymer composites simultaneously with high thermal conductivity and outstanding EMI shielding capability, which can be utilized in aerospace, telecommunications, and mobile electronic devices.