Ag Nanoparticles Embedded in Multishell Carbon Nanoparticles for Microwave Absorption

The combination of Ag nanomaterials and special nanostructures can significantly amplify the conversion of electromagnetic energy, especially in microwave absorption applications. Herein, a kind of multishell Ag/C composite nanoparticle with about 635 nm size prepared by a self-assembly method was reported, in which the Ag nanoparticles were about 20–40 nm in size. In the process of synthesis, Ag-related nanoparticles interfere with the internal cross-linking degree of phenolic polymers, and Ag nanoparticles were embedded into multishell carbon nanoparticles after acetone etching and high-temperature calcination. Studies have shown that the multishell Ag/C heterogeneous particles have excellent dielectric loss capabilities. By adjusting the Ag content, the dielectric properties and impedance matching characteristics of the particles can be optimized, and thus, the effective absorption bandwidth is 5.85 GHz ranging from 12.15 to 18 GHz at only 1.7 mm, almost covering the entire Ku band. The combination of Ag nanoparticles and multishell structure can significantly enhance the electromagnetic wave attenuation capability, which supplies a serviceable reference for the microstructure and material design of nano-absorbers.