Pomegranate like polypyrrole/nanodiamond hierarchical structures for metal-free ultrabroad-band electromagnetic absorptions

Abstract Exploring metal-free ultrabroad-band electromagnetic absorption materials is of great significance in practical application and theoretical research, which is, however, still challenging. Constructing hierarchical structures and seeking metal-free magnetic materials could be feasible ways to realizing stable, lightweight and metal-free ultrabroad-band electromagnetic absorption. In this work, pomegranate like polypyrrole/nanodiamond hierarchical structures, which could achieve metal-free ultrabroad-band electromagnetic absorptions, are synthesized through in situ polymerization. The optimal reflection loss peak reaches -53 dB at 10.5 GHz and the effective bandwidth below -10 dB could achieve 12.2 GHz, realizing 5.8-18 GHz full-coverage at a single thickness of 4.2 mm. The ultrabroad-band electromagnetic absorption results mainly from the π-p hybridization induced nanodiamond surface defect state, the multiple polarizations and interfaces, as well as the biomimetic pomegranate like hierarchical structures leading to the synergistic magnetic and dielectric dissipations. This work provides referencing path for designing metal-free ultrabroad-band electromagnetic absorption materials.