Mechanically Programmable Microwave Absorption in a Dual‐Gradient Cellulose‐Based Aerogel

ABSTRACT The rapid evolution of intelligent electronics and adaptive communication systems demands microwave absorbers capable of dynamic electromagnetic regulation and multifunctional integration, whereas most high‐performance absorbers exhibit intrinsically fixed electromagnetic properties once fabricated. Herein, a sustainable dual‐gradient cellulose‐based aerogel (A‐MoFeC) is engineered through counter‐gradient integration of CNF@MoS 2 and Fe 3 O 4 /CNT hybrids, establishing a continuous permittivity transition that enables sequential wave penetration and volumetric attenuation. The optimized A‐MoFeC achieves a minimum reflection loss (RL min ) of −61.6 dB with a maximum effective absorption bandwidth (EAB) of 6.04 GHz. Mechanical compression (0%–60% strain) induces strain‐dependent modulation of attenuation intensity and bandwidth, enabling full coverage of the X and Ku bands. This dynamic behavior originates from compression‐regulated reconfiguration of the gradient architecture, which drives evolution of conductive pathways and interfacial polarization, thereby tuning permittivity and impedance matching. Excessive compression (∼70% strain) disrupts impedance balance and triggers a reversible absorption “off” state, realizing strain‐switchable electromagnetic attenuation. Beyond adaptive absorption, the aerogel integrates pressure sensing, thermal insulation, infrared stealth, and photothermal conversion. This work establishes a sustainable gradient‐dielectric strategy for constructing broadband, mechanically programmable microwave absorbers.