Magnetic particle decorated hierarchical porous carbon with adjustable electromagnetic wave absorption and excellent Joule thermal response

This study utilized in-situ impregnation and pyrolysis, followed by annealing at 1200°C for two hours, to convert waste materials into carbon-based electromagnetic wave absorbers. Advanced analytical techniques were employed to examine the morphological and structural characteristics of magnetic wood, showing that higher precursor concentrations led to increased magnetic particle formation, structural defects, and enhanced electromagnetic absorption. The electromagnetic properties of carbonized magnetic poplar samples (CMPs) were evaluated across a broad frequency range. Additionally, a radar reflection model was constructed using CST software to further explore electromagnetic attenuation capabilities. The fabricated magnetic wood samples demonstrated a peak absorption capacity of −44.8 dB at an optimal thickness of 1.96 mm, along with a maximum bandwidth of 4.44 GHz. The porous internal structure provides multiple pathways for electromagnetic wave attenuation, significantly boosting the material’s absorption performance. In this study, the exceptional electromagnetic wave absorption performance of the composite is attributed to the preservation of the original cellular structure in carbonized poplar. The effective coupling between multi-phase magnetic iron particles and the three-dimensional skeleton induces significant interfacial polarization. Furthermore, the intricate porous network within the skeleton promotes multiple scattering and dissipation mechanisms, thereby further enhancing the material's absorption efficiency. • In situ impregnation and in situ pyrolysis were used to convert discarded poplar into electromagnetic absorber. • The reflection loss of the prepared magnetic wood can reach −44.8 dB and the maximum bandwidth can reach 4.44 GHz. • The electromagnetic attenuation ability of different materials was simulated by CST simulation software.