Multidimensional Magnetic Coupling and Heterointerface Engineering in Layered Gradient Carbon Aerogel Architected by Anisotropic CoNi Chain for Exceptional Electromagnetic Wave Absorption

Abstract Gradient materials and hierarchical structures exhibit remarkable diversity and integrity in nature. Currently, carbon‐based aerogel can explore 1D/2D hierarchical structures brought by magnetic particles, but they are limited in the fabrication of 3D gradient and magnetized functional aerogel. Herein, a 1D anisotropic CoNi alloy chain is first found to convert randomly porous structure into special gradient and layered configurations. With optimized structural reorganization, multidimensional magnetic coupling and continuous electron transport pathways are successfully formed in this 3D hierarchical magnetized aerogel. Through collaborative regulation of the CoNi chain distribution and heterointerface structure, magneto‐dielectric balance is precisely tuned to improve the impedance matching and ultra‐frequency response ability toward to incident electromagnetic (EM) wave. Meanwhile, the correlation between interfacial polarization and coupling behavior induced by the magnetic chain is established through the density‐functional theory (DFT) calculations and advanced visualized electron holography (EH) technology. Therefore, 3D layered and gradient carbon aerogel architected by 1D CoNi chain exhibited exceptional broadband absorption with the efficient absorption bandwidth up to 6.88 GHz at 2.1 mm thickness. These findings offer a new sight for designing high‐performance gradient EM wave absorption with hierarchical structures regulated by unique 1D anisotropic magnetic alloy chain.