Continuously Adjustable Impedance Gradient in Laminar Aerogels: Synergizing Matching and Multi‐Position Attenuation for Broadband Absorption
Guangyu Qin, Yanan Liu, Yuefeng Yan, Guansheng Ma, Boshi Gao, Ziyan Cheng, Tao Chen, Xiaoxiao Huang
Abstract
Abstract Impedance gradient design proves to be an effective strategy for enhancing impedance matching. However, precisely controlling the impedance gradient distribution while resolving the contradiction between impedance matching and attenuation capability remains challenging. In this study, by controlling the concentration of aramid nanofibers (ANFs) dispersion, a gradient distribution of reduced graphene oxide (rGO) nanosheets and plate‐like SrFe 12 O 19 within the aerogel is achieved. This approach enables precise control over the impedance gradient distribution during vacuum‐assisted filtration. The optimized gradient impedance distribution induces an “impedance matching and multiple attenuation positions” mechanism, enabling aerogels to demonstrate the advantages of broadband microwave absorption. Under compression from 6 to 2 mm, the effective absorption bandwidth exceeds 7.7 GHz, with a maximum reaching 12.8 GHz, covering 75% of the tested band and demonstrating excellent external pressure adaptability. Additionally, the layered, ordered pore structure and interconnected conductive network impart the aerogel with exceptional thermal insulation and Joule heating properties, enabling its application in both passive and active infrared stealth systems. This work opens new avenues for the design of gradient impedance‐compatible stealth aerogels based on 2D materials.