Biomimetic Nanoporous Brochosome Carbons with Microporous Quasi‐Superstructure for Ultra‐Broadband Microwave Absorption

ABSTRACT Carbon microwave absorbers with strong and broad absorptions are highly desired to avert electromagnetic pollution in various scenarios, however the pronounced impedance mismatch of traditional carbon greatly hinders their practical applications. Superstructures addressing this challenge have hitherto been fabricated on relatively intricate, still‐fragile routes, which stability remains a critical concern. Herein, biomimetic nanoporous brochosome carbons (BCs) with microporous quasi‐superstructure were successfully prepared using a unique hard template‐SiO 2 brochosome microspheres (SiO 2 BMs). By simply adjusting the ratio of CTAB containing SiO 2 BMs and the polydopamine (PDA), the microstructure of microporous quasi‐superstructure on the hollow wall of BCs could be fine‐turned. The obtained BCs exhibit selective heteroatom doping and localized carbonization surrounding the regularly arranged micropores, achieving an optimized impedance matching and significantly enhances the capture and dissipation of incident microwaves. Notably, BC‐2.0 shows a minimum reflection loss ( RL min ) of −54.33 dB and an ultra‐broad maximum effective absorption bandwidth ( EAB max ) of 8.85 GHz at a thickness of 2.90 and 2.89 mm, covering the full Ku‐ and X‐bands, respectively, without any magnetic particles. This work interprets the brochosome‐micropores quasi‐superstructure and spatially differentiated heteroatom doping, providing a new perspective for boosting the advances of carbon‐based microwave absorbers.