Spongy ternary nano-composites with optimized impedance matching and synergistic effect for broadband and strong microwave absorption.

To counter the negative effects of electromagnetic radiation on the immunity of precision instruments, the stealthiness of military equipment, and human health, the preparation of porous multi-component nano-composites is considered an effective strategy to obtain efficient microwave absorption. In this work, the spongy ternary nano-composites (STC) with large specific surface area (SSA) and pore volume obtained by adjusting the calcination temperature, the porous effectively improves the impedance matching. The ternary composition of FeCo/FeNi/C, large SSA and pore volume provide abundant specific surface/interface for polarization and magnetization, the continuous conductive network is established, the strong dielectric and magnetic loss achieve a synergistic effect, realizing strong absorption in the low-frequency, greatly reducing the minimum reflection loss (RL, -56.37 dB) and broadening the effective absorption bandwidth (EAB, 7.45 GHz). The microwave absorption mechanism has been analyzed in detail and its great potential for practical applications has been verified by RCS signal simulations. This research provides an effective method for fabricating high-performance ternary nano-composite microwave absorbers.