Advanced N-Graphene-Based Electromagnetic Shields via Microwave Plasma Induced Synthesis

Here, a plasma-enabled strategy is presented for the controllable fabrication of ultralight nanocomposites with absorption-dominated EM-shielding performance across the 5–70 GHz frequency range. The fabricated nanocomposites exhibit average microwave absorption exceeding 60% across the 5–25 GHz frequency range and 70% across the 25–70 GHz range while maintaining a constant thickness of 2 mm and a fixed filler content of 15 wt%. Plasma-driven nanoscale engineering and multiphase hybridization synergistically enhance dielectric and magnetic loss mechanisms, resulting in effective absorption bandwidths in the C-band (2.1 GHz), Ku-band (3.4 GHz), Ka-band (8 GHz) and V-band (4 GHz). The plasma process produces free-standing nitrogen-doped graphene sheets uniformly decorated with FexOy, MnOx, and TiOx nanoparticles, which are subsequently incorporated into a polymer matrix. The microwave plasma environment simultaneously enables graphene nanosheet synthesis, metal oxide nanoparticles formation, surface functionalization, multiphase generation, and the anchoring of nanoparticles onto the graphene scaffold. Using low-cost precursors such as acetonitrile and micron-sized metal oxides, the process achieves production rates of up to 50 mg min−1. Overall, this one-step plasma-enabled approach provides a low-cost, scalable, and efficient route for manufacturing lightweight, high-performance EM wave absorbers.