Tailoring Cross‐Scale Structures in Dual‐Transition Metal MXene Aerogels for Robust Microwave Absorption

ABSTRACT Achieving broadband microwave absorption while maintaining a thin profile is a challenge due to the conflict of inherent impedance with attenuation. Herein, dual‐transition metal /rGO/ aerogels featuring cross‐scale structural tailoring, ranging from the nanoscale to the millimeter scale, were fabricated via freeze‐drying. At the nanoscale, the solid‐solution incorporation of Nb atoms introduces additional polarization loss, thereby enhancing the intrinsic attenuation capacity of the material. At the microscopic level, by leveraging the dimensional disparity between large‐sheet rGO and small‐sheet MXene, the porosity of the aerogel walls was regulated. Therefore, the conductive networks and abundant heterointerfaces were established, enabling the TNrF‐1 to achieve an effective absorption bandwidth (EAB) of 6.24 GHz at a thickness of 2.0 mm, accompanied by a minimum reflection loss of dB. Macroscopically, the aerogels were constructed into a stepped gradient structure whose parameters were optimized by a genetic algorithm. The optimized architecture reconciles the conflict between impedance and attenuation, delivering an exceptional EAB of 14.45 GHz with superior angular robustness. This cross‐scale paradigm paves a feasible avenue for developing advanced electromagnetic functional materials.