3D dual network MOF-derived magnetic Co/Ni@C-GnP@PDMS composites for absorption-dominant EMI shielding with enhanced thermal conductivity

Abstract

With the rapid advancement of electronic devices and communication technologies, developing polymer composites with absorption-dominant electromagnetic interference shielding effectiveness (EMI SE) has become increasingly important for reducing secondary electromagnetic wave radiation while simultaneously managing heat accumulation. Herein, a dual-network strategy is adopted to fabricate graphene nanoplatelet (GnP)@polydimethylsiloxane (PDMS)\Co/Ni@C composites with absorption-dominant EMI shielding behavior and improved thermal conductivity. A three-dimensional porous GnP@PDMS skeleton is first constructed via a sugar-templating method, followed by vacuum-assisted infiltration of carbonized magnetic (CM) nanoparticles derived from Co/Ni metal–organic frameworks (Co/Ni@C) to form a fully interconnected conductive–magnetic network. The synergistic construction of the conductive GnP network and magnetic Co/Ni@C network improved impedance matching and enhanced magnetic loss and interfacial polarization, leading to a transition from reflection-dominant to absorption-dominant shielding behavior. The optimized GnP30@PDMS/CM5 composites achieved an EMI SE of 71.5 dB, with an absorption coefficient of 0.69, significantly higher than 0.15 for the GnP30@PDMS composites without the magnetic Co/Ni@C component. Simultaneously, the interconnected dual network constructs efficient thermally conductive pathways that facilitate phonon transport, achieving a remarkable through-plane thermal conductivity of 1.37 W m⁻¹ K⁻¹. The GnP30@PDMS/CM5 composites also exhibited excellent heat dissipation, mechanical strength, thermal stability, and hydrophobicity. This study presents an effective design approach for constructing multifunctional polymer composites that combine absorption-dominant EMI shielding and thermal management, offering strong potential for advanced electronic applications.