Construction core–shell BCN@PANi composites with broadband microwave absorption performance

As the problem of electromagnetic pollution becomes more prominent, the design of a material with ultra-wide-band microwave absorption properties has become the focus of electromagnetic pollution prevention and control. Herein, we first used a sacrificial template method to prepare C-doped BN (BCN) using biomass carbon as a template and then used an in-situ synthesis method to grow polyaniline (PANi) on the surface of BCN to prepare BCN@PANi with a core–shell structure. As expected, the BCN@PANi composite exhibits superior microwave absorption properties with a minimum reflection loss (RLmin) of − 34.70 dB at 5.0 mm and an effective absorption bandwidth (EAB) of 14.94 GHz (3.06–18 GHz). Notably, BCN@PANi composites exhibit an ultra-wide microwave absorption bandwidth, covering 83% of the tested frequency. Additionally, the excellent microwave absorption performance is attributed to the modulation of the dielectric and magnetic properties of BN after C doping and the contribution of conductive loss to the composite performance after PANi coating. Moreover, the preparation of BCN@PANi provides a reference for preparing ceramic-based composites in the future.