Multiscale Structural Engineering in Electromagnetic Wave Absorption Materials: From Atomic Defects to Macroscopic Structures.

Against the backdrop of advances in intelligent sensing, information protection, and electronic device integration, the performance bottleneck of electromagnetic wave (EMW) absorption has gradually shifted from the intrinsic properties to the limitations of structural control strategies. Multiscale engineering, as a key approach to overcoming this bottleneck, integrates atomic/molecular, nanoscale, microscale, and macroscale levels, thereby endowing EMW absorption materials with enhanced controllability, efficiency, and intelligent tunability. Nevertheless, current multiscale studies still face significant challenges, including the unclear mechanisms of structural synergy and the reliance on empiricism in structural design. This review provides a systematic overview of the multiscale structural design and first elucidates the influence of structures ranging from atomic to macroscopic scales on the electromagnetic responses. Subsequently, the progress on EMW absorption materials in three typical synergistic strategies at atomic/molecular, nanometer, micrometer, and macroscopic scales was summarized, revealing the regulatory effect of structural evolution on EMW absorption performance. This review particularly emphasized the cross-scale structure-function coupling mechanism, such as dipole polarization, interface loss, multiple scattering, and impedance matching. Finally, the main challenges currently facing multiscale structural engineering in the field of EMW absorption are summarized, and future development directions are outlined from the perspective of material design and performance optimization.