Design of biomass-derived magnetic carbon/polyaniline with hierarchical network for superior microwave absorption

Recently, microwave absorbers with strong absorption along with wide absorption band have gained abundant attention due to their low cost, simple fabrication, and sustainability. However, it remains a challenge for pure biomass to achieve this goal without adding other components. Herein, a wheat flour-derived magnetic carbon nanocomposite was prepared and hydrochloric acid was used to fabricate doped PANI on the magnetic porous carbon (MPC), in which PANI was grown on the MPC network. The introduction of NiFe2O4 particles is helpful in balancing permittivity, permeability, and impedance matching. This distinctive PANI structure heightens conductive loss, interfacial polarization, and multiple reflections of the incident EM waves. Overall, the optimal reflection of NiFe2O4/PC/PANI can reach up to -59.3 dB at 2 mm with 20 wt% filler loading and the efficient bandwidth (R-L exceeding -10 dB) is as wide as 5.6 GHz (12.4-18 GHz) with a thickness of 1.5 mm. To sum up, this strategy provides a novel scope for the controllable construction of a hierarchical carbon composite and the as-prepared composite possesses a promising potential for exploration of biomass carbon on high-performance microwave absorbers.