Enhanced Absorption‐Dominated EMI Shielding in Epoxy/Reduced Graphene Oxide/Multi‐Walled Carbon Nanotube Hybrid Nanocomposites

Polymer‐based nanocomposites with enhanced electromagnetic interference (EMI) shielding performance have attracted considerable attention for mitigating unwanted electromagnetic radiation in electronic and communication systems. In this work, epoxy‐based nanocomposites containing 0–9 parts per hundred resin (phr) of reduced graphene oxide (RGO), carboxyl‐functionalized multi‐walled carbon nanotubes (f‐CNT), and RGO/CNT hybrid fillers were fabricated and systematically investigated for EMI shielding performance in the X‐band frequency range (8–12 GHz). Electrical conductivity and EMI shielding efficiency increased with filler loading. The hybrid nanocomposites displayed superior shielding effectiveness, reaching a maximum of 28 dB at 9 phr, corresponding to 99.8% attenuation of incident electromagnetic radiation, and exceeding the 20 dB threshold for commercial applications. The average reflection, transmission, and absorption coefficients were 19.6%, 0.34%, and 80%, respectively, corroborating absorption‐dominated EMI shielding. The hybrid nanocomposites exhibited higher EMI shielding effectiveness than single‐filler‐incorporated nanocomposites. Partially replacing relatively expensive carbon nanotubes with RGO offers a feasible strategy for achieving cost‐effective electromagnetic attenuation suitable for commercial applications. Because of their lightweight characteristics, enhanced EMI shielding effectiveness, and absorption‐dominated shielding that limits secondary electromagnetic pollution from reflected radiation, the hybrid epoxy nanocomposites are promising for electronic packaging, telecommunications, automotive electronics, wearable devices, and lightweight aerospace structural applications.