Facile synthesis of three-dimensional lightweight nitrogen-doped graphene aerogel with excellent electromagnetic wave absorption properties

The widespread use of communication facilities and electronic devices has increased the demand for novel high-efficiency and lightweight microwave absorption materials. In this work, we propose using N-doped graphene (NG)/wax composites, where an interconnected 3D graphene network is used as filler in a wax matrix. Nitrogen atoms were substitutionally doped into the graphene lattice by hydrothermal method. It was found that controlling the amount of NG could effectively modulate the electrical properties of graphene. Inspection of the samples prepared showed that to a large extent, the vacuum infusion method effectively retained the graphene intact 3D structure. Samples filled with 3.6 wt% NG exhibited the most prominent microwave absorption properties; the minimum reflection loss registered was 53.25 dB at 13.10 GHz for a sample thickness of 3.3 mm, and the bandwidth of the reflection loss less than 10 dB (90% absorption) can reach up to 8.15 GHz. The result indicates that the nitrogen-doped graphene can greatly improve the dielectric loss of electromagnetic wave absorber. More importantly, the work presented provides the framework for a unique facile approach to manufacture low-cost NG/wax composites with strong electromagnetic wave absorption ability at very low filler loading.