Recently, a research team led by Professor Wang Wei from the Faculty of Mathematics and Physics published a research paper entitled "Multi-scale engineering for enhancing broadband microwave absorption, electromagnetic shielding and infrared stealth of Ag NWs/N-doped rGO aerogels" online in the prestigious journal Advanced Functional Materials.
This study employed a directed freeze-drying and heat treatment process to fabricate silver nanowire/N-doped reduced graphene oxide composite aerogels (Ag/N-rGO) with aligned pore structures. At the microscopic scale, by controlling the nitrogen doping content, abundant structural defects were introduced, tailoring the electronic structure and polarization behavior, thereby enhancing defect polarization loss and optimizing impedance matching. At the mesoscopic scale, the aligned pore configuration effectively promoted multiple reflections and scattering of incident electromagnetic waves, prolonging their propagation path within the material and improving dissipation efficiency. At the macroscopic scale, the team further engineered a periodic stepped structure to stimulate multi-frequency resonance effects, enabling efficient electromagnetic wave absorption across different frequency bands. Experimental results demonstrated that the Ag/N-rGO composite aerogel, with an ultra-low filler loading of only 4 wt%, achieved a minimum reflection loss (RL<sub>min</sub>) of –56.32 dB and an effective
absorption bandwidth (EAB, RL ≤ –10 dB) of 7.04 GHz, entirely covering the K<sub>u</sub> band. The periodic structure design further broadened the EAB to 14.64 GHz, representing a remarkable enhancement of 207.9%, and showcasing superior broadband microwave absorption performance. Furthermore, the Ag/N-rGO aerogel possesses outstanding EMI shielding effectiveness and promising passive and active infrared stealth capabilities. Through this multi-scale structural design strategy, synergistic optimization across the micro-, meso-, and macro-scales was realized.
BUCT is the correspondence affiliation for this paper. Tingyuan Zhang (Master's candidate, Class of 2024) is the first author, and Professor Wang Wei is the corresponding author. This research was supported by the National Natural Science Foundation of China.
Paper link: https://doi.org/10.1002/adfm.202521010
Graphical Abstract:
Figure 1. a) The synthesis diagram of Ag/N-rGO aerogel. The SEM images of b) Ag NWs and c, d) side surface and e) layer interior of Ag/N-rGO-1 aerogel. f) The SEM and g) EDSelemental distribution of Ag/N-rGO-1 aerogel. h) TEM images of Ag NWs, i) TEM and j) HRTEM images of Ag/N-rGO-1 aerogels.
Figure 2. The calculated RL value of samples a) Ag/rGO, b) Ag/N-rGO-1, c) Ag/N-rGO-2 and d) Ag/N-rGO-3. e) The attenuation constant of samples. f) The relationship among RL, MZ and 𝛼 of sample Ag/N-rGO-1 at a thickness of 2.59 mm. g) The microwave absorption performance of Ag/N-rGO aerogel compared to other similar materials.Figure 4. The calculated RL value of samples a) Ag/rGO, b) Ag/N-rGO-1, c) Ag/N-rGO-2 and d) Ag/N-rGO-3. e) The attenuation constant of samples. f) The relationship among RL, MZ and 𝛼 of sample Ag/N-rGO-1 at a thickness of 2.59 mm. g) The microwave absorption performance of Ag/N-rGO aerogel compared to other similar materials.
Figure 3. a) The schematic of the RCS simulation model, b) RCS values of the samples at different angles and c) RCS reduction of the absorber layer comparedtoPEC.d)Thecellsoftheperiodic structure, e) a schematic of the periodic structure and its f) microwave absorption performance. The power loss densities of periodic structures at g) 4.05, h) 10.87 and i) 15.76 GHz. j) Microwave absorption mechanism diagram of Ag/N-rGO aerogels.
Figure 4. The EMI a) SET,b)SEA,c)SER. The infrared images of the samples placed d) on a heat source at 90 °C and e) on the hand. f) The thermal conductivity of samples. g) The temperature change curves and h) infrared images of Ag/N-rGO-1 before and after loading voltage.
Corresponding Author Biography:：
Wang Wei, Professor and Doctoral Supervisor, serves as the Dean of the Faculty of Mathematics and Physics at Beijing University of Chemical Technology. He obtained his Ph.D. from Shanghai Jiao Tong University in 2006. Supported by the National Natural Science Foundation of China (NSFC), he visited the International Centre for Theoretical Physics (ICTP, Italy) in 2012 and was a visiting scholar at the University of Texas at Arlington (USA) from 2014 to 2015. He has led numerous research projects including the NSFC General Program, NSFC Young Scientists Fund, NSFC International Cooperation and Exchange Program, Beijing Natural Science Foundation General Program, and enterprise commissioned projects. He has authored over 100 SCI-indexed papers, including 13 recognized as ESI "Highly Cited Papers." He serves on the editorial boards of several journals, including Journal of Materials Engineering and Journal of Aeronautical Materials, and has received honors such as the Beijing Outstanding Talent award. Professor Wang Wei's research team primarily focuses on theoretical and experimental studies related to the preparation, performance modulation, and functional applications of low-dimensional magnetic materials, spanning areas such as photoelectrocatalysis, adsorption separation, and electromagnetic wave absorption/shielding.