Tailoring Nitrogen Configurations in Porous N-Doped Graphene Films for Electromagnetic Interference Shielding Performance

Electromagnetic pollution has become an increasing concern in emerging technologies such as 5G communications. Therefore, lightweight and efficient electromagnetic interference (EMI) shielding materials are of considerable importance. Three-dimensional porous nitrogen-doped graphene (NG) films were fabricated through a hybrid coating process followed by heat treatment, using graphene oxide (GO) and urea as precursors. By adjusting the urea content, the relative distributions of pyridinic N, pyrrolic N, and graphitic N were optimized, and a lightweight porous architecture was formed by gases released during the pyrolysis of the nitrogen source and GO. At a GO/urea mass ratio of 1:0.15 (NG15), the sample delivered the best EMI shielding performance in the 8.2–12.4 GHz range, with an average total shielding effectiveness (SE T ) of 93.2 dB, an absolute shielding effectiveness (SSE T ) of 14562.5 dB·cm 2 ·g –1, and an electrical conductivity of 3185.63 S cm –1 . This performance is mainly attributed to the synergistic effect of graphitic N-dominated doping and the porous structure. N-doping increases conductivity and defect density, thereby enhancing conduction and polarization losses, while the three-dimensional porous architecture promotes multiple reflection and scattering for improving electromagnetic wave dissipation. This study provides insight into the structural design of high-performance, lightweight EMI shielding materials for advanced electronic applications.