Modulation of Dielectric Behavior in Nitrogen-Doped Accordion-Like Carbon Materials for Enhanced Electromagnetic Response

Demand for lightweight and efficient electromagnetic wave (EW) absorbers continues to increase with technological advances in highly integrated electronics and military applications. Nitrogen doping is known to improve dipole polarization, contributing to broadband microwave absorption. In this work, nitrogen-doped carbon nanosheets with unique accordion-like structures were successfully synthesized via direct carbothermal reduction of uric acid. These architectures exhibit augmented microwave absorption resulting from synergistic loss effects including interfacial and dipole polarization. Furthermore, nitrogen doping results in the formation of lattice defects and electronic transport in three-dimensional conductive networks; these features collectively contribute to optimizing impedance matching and increasing the microwave absorption characteristics of materials. The high-temperature pyrolysis directly influences the graphitization degree, thereby significantly improving the dielectric loss. Experimental results demonstrate that the N-ALC-800 materials, at a filler content of 20 wt %, exhibit outstanding microwave absorption performance with an effective absorption bandwidth of 6.0 GHz. Furthermore, computer simulation technology (CST) indicates that the radar cross-section (RCS) value can be effectively reduced to 34.7 dB·m2. This study offers new insights and practical guidance for designing lightweight and high-efficiency carbon-based microwave absorbers.