N and S dual doping and defect engineering to modulate electronic structure of 3D honeycomb-like carbon for boosting microwave absorption

The rapid advancement of information technology has caused an increase in electromagnetic interference, making the development of high-efficiency electromagnetic (EM) wave absorbers an urgent area of interest. However, the design of EM wave absorbers faces certain bottlenecks, such as the lack of narrow bandwidths and heavy weights. In this study, novel nitrogen–sulfur dual-doped 3D honeycomb-like carbon was fabricated as an EM wave absorber by heteroatom doping and defect engineering to modulate the electronic structure to regulate the defect and migration energy barriers, thus facilitating impedance matching between nanosheets and air, enhancing charge transfer, and producing numerous active sites for dipole polarization. Crucially, the combination of honeycomb-like carbon and nanosheets provides an abundance of conductive paths, heterointerfaces, and inner cavities, resulting in lightweight and absorption bandwidth enhancement. Moreover, the material demonstrated excellent EM wave absorption properties, having a high-efficiency loss of −60.3 dB and an effective absorption bandwidth up to 7.36 GHz at only 8 wt% filler content. Additionally, this material showed a low corrosion current density (1.094 × 10⁻⁶ A) and high polarization resistance (39.22 kΩ), maintaining excellent stability and corrosion resistance in simulated seawater. This research provides valuable perspectives for the investigation of dielectric loss and the advancement of multifunctional EM wave absorption materials.