Hydrothermal synthesis of nitrogen-doped graphene as lightweight and high-efficient electromagnetic wave absorbers

Exploring lightweight electromagnetic wave absorption materials is urgently needed to satisfy the miniaturization and integration of artificial intelligence and 5G technologies. Herein, nitrogen-doped graphene (N-GN) is successfully fabricated through a simple hydrothermal method, which can float in the water. Except for keeping the sheet-like structure of GO, nitrogen-doped graphene shows a reticular-like structure with more wrinkles and crinkles, which is crossed and interconnected to each other. The introduced nitrogen heteroatoms may induce dipole polarization, and the special interconnected reticular-like structure may improve the energy dissipation capacity. These features make nitrogen-doped graphene process improved dielectric loss and enhanced electromagnetic wave absorption performance. When the mass fraction of N-GN is only 10 wt%, N-GN shows a maximum reflection loss value of - 21.7 dB at 14.3 GHz with an absorber thickness of only 1.78 mm. This work indicates that nitrogen-doped graphene is a good candidate of lightweight dielectric materials.