Multidimensional Nanostructures Design of Poly-Imidazolium Salts Derived N-Doped Carbon Materials for Electromagnetic Microwave Absorption

Poly-imidazolium salt (PIS) combines the merits of abundant nitrogen sources, excellent chemical and thermal stability and adjustable morphology, making it a promising precursor for Nitrogen-doped (N-doped) carbon material. Herein, multidimensional PIS are synthesized via a facile solvent-induced strategy. Then, PIS are converted into nanofibers, nanoribbons and microspheres composed of N-doped carbon. The effects of microstructure, N-doping degree and defects on microwave absorption properties are investigated in depth. As a result, the 2D nanoribbon CN-2-700 features a high specific surface area, significant N-doping and moderate conductivity, thereby allowing it to sustain perfect conductive networks and the optimal impedance matching at a low filler content (8 wt.%). CN-2-700 demonstrates a minimum reflection loss (RL_min) of −50.15 dB and an effective absorption bandwidth (EAB) of 7.06 GHz (10.44–17.50 GHz). Overall, this work offers a novel path for developing multi-dimensional electromagnetic microwave absorbing materials with a simple process and remarkable performance.