MXene@Co hollow spheres structure boosts interfacial polarization for broadband electromagnetic wave absorption

MXene is considered as a candidate for preparing high-performance electromagnetic wave absorbing materials due to its large specific surface area, rich surface modification groups, and unique metal properties. However, the impedance matching problem caused by its high conductivity and easy stacking properties is a limiting factor. In this study, a self-assembling-etching-anchoring growth method was proposed to prepare MXene@Co electromagnetic wave absorbing materials. The hollow structure of MXene microspheres constructed with PMMA as a hard template is conducive to optimizing impedance matching and surface modification. In addition, MXene@Co exhibits abundant heterogeneous interfaces, enhancing the interfacial polarization phenomenon during electromagnetic wave absorption. Meanwhile, the surface-anchored growth of magnetic Co particles forms a magnetic network, which provides a strong magnetic loss capability for the absorber. The hollow structure design significantly enhances the wave absorption performance compared to conventional MXene@Co composites, with a minimum reflection loss of −57.32 dB (effective absorption bandwidth of 5.2 GHz) when the thickness is 2.5 mm (2.2 mm). This work provides a meaningful reference for the design of MXene-based electromagnetic wave absorbing materials.