Ni–Fe Nanoparticles Embedded in N‑Doped Carbon for Broadband Microwave Absorption

With the advent of the 5G era, there has been increasing concern regarding the potential harm of electromagnetic wave radiation on human life. Consequently, the development of a simple and cost-effective broadband and high-performance microwave absorber becomes crucial. In this study, porous tremella like nanomaterials embedded with Ni–Fe nanoparticles in N-doped carbon were prepared by a simple salt template method. Given that carbon materials inherently lack magnetic loss due to their own dielectric loss, in order to enhance microwave absorption capacity, FeNi bimetal is added to introduce magnetic loss to achieve electromagnetic synergy. By changing the pyrolysis temperature, adding NaCl and urea, the morphology of the material can be adjusted, the electromagnetic parameters can be changed, and the impedance matching can be adjusted to improve the microwave absorption performance. At a 7.5% filling ratio of the synthesized FeNi/N–PCN(800) composite, the minimum reflection loss (RLmin) is −46.4 dB, with a mere 2 mm matching thickness. The effective absorption bandwidth extends up to 5.04 GHz, demonstrating successful broadband microwave absorption. The radar cross section further proves that the material has good microwave absorption characteristics in practical applications. This work offers a reliable idea for subsequent studies on broadband and high-performance microwave absorbing materials.