2D-high entropy alloys embedded in 3D-carbon foam towards light-weight electromagnetic wave absorption and hydrophobic thermal insulation

The escalating demand for high-performance applications, such as drones, smart wearables, and military communication systems, is increasingly challenged by extreme conditions, including high temperatures, humidity, and intense electromagnetic interference. Overcoming these obstacles requires advanced electromagnetic wave (EMW) absorbing materials with exceptional environmental adaptability. In this work, we introduce a multifunctional and efficient EMW absorber (i.e., CMF/HEA), which combines lightweight, thermal insulation, and hydrophobic properties. The unique integration of carbonized melamine foam (CMF) with magnetic high-entropy alloy (HEA) nanosheets not only provides a lightweight framework but also enhances EMW attenuation due to the inherent lattice distortion and high-entropy effects of the HEA nanosheets. This combination achieves a remarkable minimum reflection loss (RL) of −74.86 dB and an effective absorption bandwidth (EAB) of 7.94 GHz with only 12 wt% filling, maintaining a low material density. Additionally, the composite exhibits excellent thermal insulation and hydrophobicity, featuring thermal camouflage and a water contact angle of 130°, ensuring device stability under extreme conditions. Simulation results demonstrate that the CMF/HEA not only optimizes impedance matching but also introduces a multi-scale absorption mechanism, offering a novel and versatile approach to EMW absorption for complex practical applications.