Multi-morphology composite: Particle & petal-shaped ZnFe2O4/flower-shaped ZnO@Porous biomass carbon with excellent broadband microwave absorption performance

Utilizing carbon and magnetic components to construct microwave-absorbing composites with broadband and strong absorption has become a research focus. Improving the structural coupling of these materials to enhance impedance matching and dielectric performance remains a significant obstacle. Particle and petal-shaped ZnFe2O4/flower-shaped ZnO@chestnut shell biomass-carbon composites (ZnFe2O4/ZnO@CBC) were synthesized via a one-step sintering method. The biomass carbon-based material presents a three-dimensional framework structure, while the particle and petal-shaped ZnFe2O4 and flower-shaped ZnO are uniformly distributed on its surface. This distribution significantly improves the dielectric polarization performance and magnetic loss of the material, ultimately leading to good microwave attenuation ability through impedance matching. Taking the addition of 1 g of biomass as an example, the minimum reflection loss (RLmin) of the composite material is −50.43 dB, and the widest effective absorption bandwidth (EAB) reaches 7.13 GHz (10.87–18 GHz). Notably, the EAB of the different composite materials all remains above 6.4 GHz when the biomass addition is adjusted within the range of 1–2.5 g, indicating that they are not sensitive to the amount of biomass used and have good stability in microwave absorption performance. Moreover, the results of the simulation and modeling analyses of the radar cross section (RCS) further validate the efficacy of composite materials in attenuating microwaves. These results offer valuable insights into the stability of bandwidth in materials and the potential application of biomass in wave-absorbing materials. It also shows that the composites are highly promising and reliable candidates for microwave absorption applications due to their high-performance, wide-band, and thin-absorption properties.