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

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.