Encapsulation of metal particles in porous carbon by microarchitectural design for lightweight and efficient microwave absorption

Abstract

The construction of heterojunctions in carbon materials is an effective means of preparing absorbers, but still faces challenges in practical applications. In this paper, N-doped porous C/Cu composites with three-dimensional highly conductive structures were prepared from sustainable biomass materials using a microarchitectural design strategy. The results of the study show that the porous structure provides more electromagnetic wave reflection sites on the surface of the material. The doping of N atoms and the embedding of Cu microspheres improve the impedance matching as well as the transmission path of the microcurrents, and the presence of relaxation polarization in the heterojunction at the interface of the carbon matrix and Cu microspheres is of great importance for the enhancement of the microwave absorption properties. The sample has a minimum reflection loss of −60.68 dB and has a maximum effective absorption bandwidth of 5.92 GHz. The CST simulation results verify the outstanding microwave absorption performance of N-doped porous C/Cu composites, with RCS reduction values up to 19.14 dBm2 at a scattering angle of 0 °C. This work provides new insights into the preparation and practical application of high-performance microwave absorbing materials.