Ultralight aerogels based on 2D van der Waals ferromagnets toward tunable and high-performance microwave absorption

Abstract

The rapid advancement of communication technologies and the miniaturization of electronic devices have the demand for high-performance, lightweight microwave-absorbing materials. However, constructing efficient microwave absorbers using two-dimensional (2D) ferromagnetic materials remains a significant challenge. In this work, 2D van der Waals ferromagnetic Fe5GeTe2 (FGT) crystals were synthesized via chemical vapor transport, and FGT nanosheets were subsequently obtained through liquid-phase exfoliation. Subsequently, this study integrated FGT nanosheets with aramid nanofibers (ANFs) to construct ultralight aerogels via a synergistic vacuum-assisted filtration and freeze-drying techniques. The resulting FGT/ANF (AFGT) aerogels exhibit tunable densities (12.4–38.7 mg/cm3) and exceptional microwave absorption properties. The optimized AFGT-3 aerogel demonstrated superior microwave absorption performance, achieving a minimum reflection loss of −48.4 dB at 9.8 GHz with a thickness of 1.9 mm, alongside an effective absorption bandwidth of 3.4 GHz (9.2–12.6 GHz). This work not only pioneers the application of 2D van der Waals ferromagnets in functional aerogels but also provides a viable strategy for developing next-generation ultralight electromagnetic protection materials.