Multi-Scale Engineering for Enhancing Broadband Microwave Absorption, Electromagnetic Shielding and Infrared Stealth of Ag NWs/N-doped rGO Aerogels

Abstract

The scale engineering aims to integrate spatial layout and arrangement patterns at different scale levels, including microscopic atomic arrangement, mesoscopic morphology and macroscopic structures. This will trigger powerful physical effects and demonstrate great potential in enhancing the electromagnetic properties of materials. Herein, Ag nanowires and N-doped reduced graphene oxide are combined to prepare a composite aerogel with directional pore structure through targeted freeze-drying technique. The enhanced microwave absorption properties are obtained through micro- and macro-scale engineering by atomic doping and periodic structure design. After optimizing the N-doping amount, the composite aerogel exhibits superior microwave absorption performance at a filling ratio of only 4 wt.%, where a minimum reflection loss (RL_min) achieves at –56.32 dB and an effective absorption bandwidth (EAB) reaches 7.04 GHz, covering the entire K_u-band. Moreover, the periodic structure can excite resonance within different frequency ranges, thereby expanding the EAB of the aerogel to 14.64 GHz with an increase of up to 207.9%. Impressively, the obtained aerogel exhibits excellent electromagnetic interference shielding efficiency (–35.55 dB) as well as outstanding active-passive infrared stealth capabilities. Therefore, this multi-scale collaborative design strategy effectively improves the electromagnetic properties of the composites, providing a guidance for addressing electromagnetic pollution and multi-spectral stealth issues.