Gradient magneto-dielectric heterostructured aerogels with MXene hollow spheres for integrated...

The escalating electromagnetic pollution crisis driven by 5G/6G technologies necessitates lightweight multifunctional absorbers with integrated electromagnetic-thermal management capabilities. Herein, we pioneer a gradient magneto-dielectric heterostructured aerogel that synergistically integrates magnetic MXene hollow spheres (HM) with a conductive polyimide network. This hierarchical architecture leverages spatially graded functional layers to achieve unprecedented electromagnetic wave dissipation and thermal stealth. The magnetic-functionalized HM establish a multi-scale electromagnetic trap, inducing intensive interfacial polarization and magnetic-dielectric coupling losses. Simultaneously, the vertically aligned channels in the polyimide-based aerogel matrix provide exceptional phonon scattering pathways for thermal insulation. This rational design enables ultrabroadband electromagnetic wave absorption with a minimum reflection loss of -52.5 dB at 1.3 mm and an effective absorption bandwidth covering 7.54 GHz. It is noteworthy that when the material was exposed to a substrate at 220 °C, the surface temperature dropped to 82.7 °C, coupled with an average infrared emissivity of 0.75 for adaptive thermal camouflage. Further, the aerogel exhibits 51% suppression in peak heat release rate and maintains structural integrity under 60% compressive strain. This work establishes a paradigm-shifting gradient heterostructure strategy that transcends conventional impedance matching limitations, opening new avenues for next-generation electromagnetic-compatible materials in aerospace, wearable electronics, and defense systems.