High-Performance Radar–Infrared-Compatible Stealth MXene/BC/Fe3O4 Composite Aerogel

The rapid development of multispectral detection technology has severely restricted single-band stealth materials, driving the demand for radar–infrared-compatible multispectral stealth. However, conflicts between the stealth mechanisms of these two bands pose significant challenges. Herein, a lightweight and highly elastic composite aerogel composed of 0D Fe 3 O 4 nanoparticles, 1D bacterial cellulose (BC), and 2D MXene nanosheets is fabricated via self-assembly and bidirectional freeze-drying. The porous structure and component optimization effectively prevent MXene nanosheet stacking and improve impedance mismatch. Benefiting from excellent dielectric–magnetic coupling, the aerogel achieves a minimum reflection loss (RL min ) of −76 dB at 1.52 mm, the absorption efficiency per unit thickness reaches an excellent value of −50 dB/mm, an effective absorption bandwidth (EAB) of 5.12 GHz at 1.54 mm, and a maximum radar cross-sectional (RCS) reduction of 30 dB·m 2 , demonstrating outstanding radar stealth. Moreover, it exhibits excellent thermal insulation (thermal conductivity of 0.049 W/m·K) and a low infrared emissivity of 0.666 (8–14 μm), enabling remarkable infrared camouflage. This work provides a simple and efficient strategy for developing high-performance radar–infrared-compatible stealth materials.