Multiscale magnetic-electric synergy in CIP/MXene/epoxy nano-micro composites for ultra-broadband absorption and enhanced thermal conductivity

Electromagnetic waves (EMWs) in the millimeter-wave (MMW) to terahertz (THz) range have attracted significant attention due to their applications in wireless communications, security imaging, radar detection, and atmospheric or astrophysical research. However, the utilization of high-frequency EMWs presents challenges, particularly in electromagnetic compatibility and thermal management. In this study, we developed a composite coating with both excellent EMWs absorption and high thermal conductivity by integrating carbonyl iron powder (CIP) microspheres, MXene nanosheets, and epoxy (EP) resin. By harnessing the multiscale complementarity of CIP microspheres and MXene nanosheets, as well as the synergistic effects of low-frequency magnetic loss and high-frequency electric loss mechanisms, the composite coating achieved ultra-broadband absorption across the MMW (26.5 GHz) to THz (3 THz) range with a thickness of only 1.5 mm. The average reflection loss (ARL) of the coating is as low as −15.36 dB, and it maintains stability at temperatures up to 300 °C, with a high thermal decomposition temperature of 439.6 °C. These results indicate that the coating can effectively mitigate external electromagnetic interference (EMI) and device heating when applied to electronic components. This research offers an innovative solution to address both EMI effects and thermal management challenges in high-frequency broadband electromagnetic systems.