Ultralight Aerogels Based on 2D van der Waals Ferromagnets toward Tunable and High-Performance Microwave Absorption

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 (ANF) 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.