Preparation and properties of starch-based carbon aerogel/FeCoNi composite wave-absorbing materials

To address the increasingly serious electromagnetic pollution problem in the era of 6G communication, electromagnetic wave-absorbing materials have gradually become a research focus in modern society. In this work, cassava starch was selected as the precursor, and FeCoNi precipitates were introduced. Starch-based aerogel/FeCoNi composite wave-absorbing materials (FeCoNi/SA) were obtained through sol-gel and freeze-drying processes. Afterward, starch-based carbon aerogel/FeCoNi composite wave-absorbing materials (FeCoNi/SCA) were produced via high-temperature carbonization in a vacuum muffle furnace. The microstructure, chemical features, and wave-absorbing performance of FeCoNi/SCA were examined, and the absorption mechanism was discussed. The results indicated that at a matching thickness of 3 mm, the minimum reflection loss (RL_min) reached -60.89 dB, and the effective absorption bandwidth (EAB) was 6.27 GHz (7.31-13.58 GHz). When the matching thickness increased to 3.5 mm, the EAB expanded to 7.91 GHz (5.61-13.52 GHz). This type of material combines a lightweight porous architecture and a magnetic-dielectric synergistic loss effect, providing a feasible strategy for the development of high-efficiency and environmentally friendly wave-absorbing materials.