Bio-based derived carbon materials for permittivity metamaterials: dual efficacy of electromagnetic wave protection and Joule heating

Epsilon-negative metamaterials (ENMs) have attracted extensive research interest due to their unique physical properties and advanced applications in electromagnetic fields. In this study, carbonized wood@Prussian blue derivative (CW@PBD) metacomposites were fabricated from a carbonized wood@Prussian blue analogue (PBA). By varying the PBD content, the negative permittivity constant of the supercomposite can be tuned between -45 and -20. The CW@PBD metacomposites exhibit outstanding electromagnetic interference (EMI) shielding effectiveness of 39 dB, with a significant 40.9% increase in absorption loss (SE_A). Notably, as the PBD content rises, the CW@PBD composites transform from EMI shielding to microwave absorption. The minimum reflection loss (RL_min) reaches -49.2 dB, and the effective absorption bandwidth (EAB) covers the entire X-band. Moreover, the CW@PBD metacomposites demonstrate remarkable Joule heating capabilities, achieving a steady-state saturation temperature (<i>T</i>_s) of 255.68 °C at 3 V. This research offers a promising approach for synthesizing ENMs, endowing biomass-based materials with desired functions for electromagnetic applications.