Enhanced dielectric loss in N-doped three-dimensional porous carbon for microwave absorption

Abstract

In this work, a three-dimensional porous carbon structure was constructed in situ by connecting carbon polyhedrons with graphitic nanosheets. The rich pores, high nitrogen doping content, and abundant defects formed on the surface provided multiple antennas to absorb electromagnetic waves. The optimized reflection loss of the material was as low as −41.65 dB with an effective absorption band of 5.84 GHz, which covered the entire Ku band. A mechanistic investigation based on density functional theory calculations and electrochemical analysis shows that the dipole loss and conduction loss were mainly caused by pyrrolic nitrogen and the higher electron mobility in the prepared materials. The conduction loss and polarization loss synergistically improve the absorption performance of nanosheet-linked porous carbon (NLPC). Furthermore, the potential practical application performance of the material, which was evaluated by computer simulation technology (CST), showed that all simulated RCS values were lower than 20 dBm2. Thus, this work provides new insights and methods to understand the microwave absorption properties of carbon materials.