Synergistic dielectric-magnetic modulation of CoFe₂O₄@MnO₂@C composite for superior microwave absorption performance

Designing optimal microstructures and balancing dielectric-magnetic regulation is an effective strategy for optimizing impedance compatibility and boosting the electromagnetic wave (EMW) absorption capability of absorbers. This study uses pomegranate peel as a carbon source, through sintering activation and a one-step solvothermal method, prepares a CoFe₂O₄@MnO₂@C (CMC) composite with a hierarchical porous structure, where biomass-derived porous carbon serves as the backbone and is modified with flower-like dielectric materials and magnetic metal oxides. By regulating the proportion of porous carbon, dielectric phases, and magnetic constituents, the composite material's dielectric and magnetic dissipation abilities can be tailored, strengthening the synergistic interaction among its components. CMC-1 exhibits outstanding microwave absorption capability, attaining a lowest reflection loss (RL_min) of −56.80 dB at a 2.22 mm layer thickness, along with an effective absorption bandwidth (EAB) of 6.80 GHz when the thickness is 2.38 mm. In addition, simulations of the radar cross section (RCS) for various composites showed that at different incident angles, CMC-1 consistently exhibits an RCS below −10 dB m2. This work offers a practical approach for improving the EMW absorption capabilities of conductive materials and for the development, fabrication, and utilization of high-performance biomass-derived absorbers.