Heterointerface engineering of CoO/Co with ordered carbon for synergistic magnetoelectric coupling to enhance wideband microwave absorption

Highly developed electronic information technology has undoubtedly resulted in numerous benefits to the military and public life. However, the resulting electromagnetic wave (EW) pollution cannot be ignored. Therefore, the application of highly efficient EW materials is becoming an important requirement. In this study, magnetic-dielectric heterointerface strategy was applied to construct absorbers with desirable electromagnetic wave properties. A novel CoO/Co nanoparticle anchored to N-doped mesoporous carbon (CoO/Co/N-CMK-3) composites was fabricated by facile precipitation reaction and the electromagnetic characteristics have been well optimized by adjusting pyrolysis temperature. The CoO/Co/N-CMK-3 yielded its highest performance at an annealing temperature of 800 °C, with an extended effective absorption bandwidth of 5.83 GHz and unusually low minimum reflection loss of−63.82 dB, even at a thickness of just 1.8 mm and low filler loading (10%). For the excellent microwave absorption property, the advantages of the CoO/Co/N-CMK-3 can be summed up as follows. Firstly, the incorporation of heterointerfaces among N-CMK-3, CoO, and Co introduces abundant polarization centers, triggering various polarization effects and increasing dielectric losses. Secondly, the CoO/Co magnetic component introduced the strong magnetic loss and improved the impedance matching capability of CoO/Co/N-CMK-3. Thirdly, the extraordinary magnetic-dielectric behavior is supported by multiple magnetic coupling networks and enriched air-material heterointerfaces, boosted the magnetoelectric cooperative loss for further optimizing the electromagnetic dissipation and broadening the effective absorption frequency band. Moreover, the CST simulation results validate the impressive operational bandwidth and reflection loss characteristics of the obtained absorbers. This study demonstrates a novel heterointerface engineering strategy for designing lightweight, wide-band, and high-performance EW absorbers.