Achieving synergistic absorption of electromagnetic waves (EMWs) in the mid-high frequency and absorption band conversion is an urgent problem. However, the present solution is usually a straightforward mixture of magnetic component-carbon component. Hereby, we optimize the magnetic properties and electrical relaxation response from a chemical synthesis perspective. Through integrated design, the contents of carbon components and multi-dimensional morphology are controlled by retaining strong magnetic properties. The morphology design and the construction of heterogeneous interfaces will boost the intense response of charge in the surrounding to enhance the polarization effect. The multi-dimensional structure and electromagnetic (EM) properties of the sample after optimized engineering have an extremely powerful absorption conversion effect on EMW energy. NiCo@C particles ultimately achieve synergistic absorption effects at low thickness (d < 3.5 mm) at middle frequencies (6–10 GHz) and high frequencies (10.5–18 GHz). Our work establishes a correlation mechanism between the physical and chemical properties of materials and EM parameters. It also provides insight into the synergistic absorption of EMWs in the mid-high frequency and absorption band conversion strategies.

The development of multifunctional materials and synergistic applications of various functions are important conditions for integrated and miniaturized equipment. Here, we developed asymmetric MXene/aramid nanofibers/polyimides (AMAP) aerogels with different modules using an integrated molding process. Cleverly asymmetric modules (layered MXene/aramid nanofibers section and porous MXene/aramid nanofibers/polyimides section) interactions are beneficial for enhanced performances, resulting in low reflection electromagnetic interference (EMI) shielding (specific shielding effectiveness of 2483 (dB·cm³)/g and a low R-value of 0.0138), high-efficiency infrared radiation (IR) stealth (ultra-low thermal conductivity of 0.045 W/(m·K) and IR emissivity of 0.32 at 3–5 μm and 0.28 at 8–14 μm), and excellent thermal management performances of insulated Joule heating. Furthermore, these multifunctional AMAP aerogels are suitable for various application scenarios such as personal and building protection against electromagnetic pollution and cold, as well as military equipment protection against infrared detection and EMI.