Versatile flexible N-doped MXene based composite films via multidimensional heterostructure engineering for multiband thermal and electromagnetic management

MXenes, celebrated for exceptional photothermal conversion, electrical and electromagnetic properties, are promising for integrated thermal-electromagnetic management. However, their cross-band synergy is hindered by high conductivity-induced strong microwave reflection and nanosheet restacking. Herein, we propose a triple-scale design strategy—microscopic defect engineering, multi-dimensional heterostructure assembly, macroscopic gradient integration—to fabricate flexible 0D/1D/2D synergistic composite films. Nitrogen-doped MXene (N-MXene) introduces lattice defects to optimize dual properties; 0D amino-functionalized hollow mesoporous silica (NH2-HMSNs) suppresses restacking and boosts dielectric loss, 1D bacterial cellulose enables flexibility, and the macroscopic gradient achieves gradual microwave impedance matching. This elaborate design achieves remarkable multifunctional synergy: under 0.5 Sun irradiation, the 65 μm-thick gradient film reaches a maximum surface temperature of 77.0 °C, while exhibiting >89% absorption in the mid-to-long-wave infrared (MWIR–LWIR) range, demonstrating compelling potential for thermal management and infrared stealth, and exhibits superior practicality: withstands loads 25,000 times its own weight, self-extinguishing and cycling stability, and achieves a reflection loss (RLmin) of –52.71 dB in 6.57–18.00 GHz, an effective absorption bandwidth (EAB) covering the entire 6.57–18.00 GHz range. This work delineates N-MXene’s multi-band potential, provides a scalable platform for programmable thermo-EM management materials, and offers insights for infrared stealth and microwave actuators.