Bottom‐Up Assembly of Biomass‐Derived MXene Aerogels with Hierarchical Electromagnetic Interfaces for Multifunctional Electromagnetic Wave Absorption

Abstract Aerogel‐based composites have demonstrated considerable potential for applications in the field of electromagnetic wave (EMW) absorption. Nevertheless, the development of such materials featuring precisely engineered microstructures, balanced magnetic/dielectric multicomponent systems, and integrated multifunctionality remains a major challenge. In this work, an MXene/lignocellulose‐derived carbon framework/Fe composite carbon aerogel is successfully fabricated through a component‐structure systematized strategy. By integrating ice‐crystal‐template‐directed assembly with subsequent carbonization, a 3D porous interpenetrating network is formed by cellulose‐derived carbon skeletons and MXene conductive nanosheets, which significantly enhances multiple EMW scattering and interfacial polarization. As a multifunctional molecular cross‐linker, lignosulfonate (LS) not only reinforced hydrogen bonding and electrostatic interactions but also effectively anchors magnetic particles, thereby achieving a synergistic enhancement of dielectric and magnetic loss mechanisms. Following precise optimization of component ratios, the sample achieves a minimum reflection loss ( RL _min ) of −51.2 dB and an effective absorption bandwidth (EAB) of 4.12 GHz at a thickness of only 1.4 mm. Moreover, the aerogel displays favorable hydrophobic‐oleophilic properties and thermal insulation. This work thus provides a feasible strategy for the development of lightweight, high‐performance, and multifunctional aerogel‐based EMW absorbing materials.