Structural coupling induced microcapacitive polarization and synergistic loss in 3D C/Ni/NiO heterostructures as high performance electromagnetic wave absorption

An rGO-cellulose carbon aerogel with coupled Ni/NiO fibers and particles enables multiscale electromagnetic regulation. • A secondary redox calcination strategy constructs high aspect ratio Ni/NiO nanofibers with abundant heterointerfaces. • Interfacial polarization, defect dipoles and magnetic loss synergistically achieve impedance matching and attenuation. • Thickness-dependent absorption enables near full band microwave attenuation and effective RCS reduction. Electromagnetic wave–absorbing materials are critical for electromagnetic interference (EMI) suppression in electronic devices and stealth applications in military equipment. Herein, a structurally coupled three-dimensional C/Ni/NiO composite is fabricated by combining a graphene-reinforced cellulose-derived carbon aerogel with in situ generated fibrous Ni/NiO heterostructures. Freeze-casting and carbonization create an interleaved conductive lamellar framework, while secondary calcination induces anisotropic growth of high-aspect-ratio Ni/NiO fibers through redox-driven stress regulation. The resulting hierarchical heterointerfaces significantly enhance interfacial polarization, anisotropic magnetic loss, and multiple scattering, fostering effective synergy between dielectric and magnetic dissipation. With optimized composition, the composite exhibits a minimum reflection loss of −50.7 dB. Furthermore, thickness tunability facilitates near-full-band absorption, and significant radar cross-section (RCS) reduction is demonstrated across a wide range of incident angles. demonstrating the potential of structurally coupled 3D heterostructures for high-performance electromagnetic wave absorption. Download: Download high-res image (240KB) Download: Download full-size image The interconnected 3D carbon–magnetic architecture enables efficient microwave penetration and multiple internal reflections, while abundant C–Ni/NiO heterogeneous interfaces induce strong interfacial polarization, synergistically coupled with defect-dipolar dielectric loss and eddy current–dominated magnetic dissipation to achieve optimized impedance matching and rapid energy attenuation. Consequently, the optimized CNO-2 exhibits an ultralow RLmin_\text{min}min of −50.7 dB at a thickness of 2.52 mm with a broad effective absorption bandwidth of 3.84 GHz. In addition, pronounced radar cross-section reduction is sustained over wide incident angles, with the main-lobe RCS suppressed from 5.37 to −27.86 dB·m², highlighting the efficacy of this lightweight, low-loading structural–interfacial coupling strategy for high-performance microwave absorbers.