Construction of chitosan-derived porous nest-like C/SnO₂ materials for microwave absorption

Electromagnetic waves have an irreplaceable role as information carriers in civil and radar stealth fields, but they also lead to electromagnetic pollution and electromagnetic leakage. Therefore, electromagnetic wave absorbing materials that can reduce electromagnetic radiation have come into being. Especially, SnO2 has made a wave among many wave-absorbing materials as an easily tunable dielectric material, but it hardly has both broadband and powerful absorption properties. Here, the nested porous C/SnO2 composites derived from nitrogen-doped chitosan is obtained by freeze-drying and supplemented with carbonization treatment. The chitosan creates a nested cross-linked conductive network that can make part of the contribution to conduction loss. The amino groups contained in the molecule either help promote in situ nitrogen doping and trigger dipole polarization. The multiphase dissimilar interface between the nested carbon layer and the inner clad SnO2 formation is the major inducer of interfacial polarization. It reached intense absorption of -48.8 dB and bandwidth of 5.2 GHz at 3.46 mm. The interfacial polarization is confirmed to be the main force of dielectric loss by simulating the electromagnetic field distribution. In addition, the RCS simulation data assure the prospect of enticing applications of C/ SnO2 composites in the field of radar stealth.