Yu Gaoyuan, Shao Gaofeng, Chen Yu, Huang Xiaogu
School of Chemistry and Materials Science, Nanjing University of Information Science & Technology, Nanjing 210044, China.
ACS Appl Mater Interfaces. 2023 Aug 23;15(33):39559-39569. doi: 10.1021/acsami.3c07988. Epub 2023 Aug 11.
Graphene-based aerogels have garnered considerable attention for their lightweight and efficient microwave absorption (MA) properties; however, optimizing the relationship between impedance matching and attenuation capability at low frequencies remains a challenge. In this study, a three-dimensional (3D) silicon carbonitride (SiCN) nanoceramic-coated graphene aerogel with conformal heterogeneous interfaces is constructed by precursor infiltration and pyrolysis to optimize MA performance at low frequencies. Thanks to the enhanced impedance matching and significant interfacial polarization of the two-dimensional sandwiched SiCN/graphene/SiCN cell walls and multiple scattering occurring within the 3D porous skeleton, the aerogel achieves a minimum reflection loss of -57.9 dB at an ultralow frequency of 4.92 GHz (C-band) and a broad bandwidth of 5.0 GHz at an ultralow thickness of 1.7 mm. The strategy developed here provides a method for enhancing dielectric polarization loss in graphene aerogels by the joint optimization of interfacial polarization and impedance matching, inspiring the design of high-performance graphene-based materials for low-frequency MA.
基于石墨烯的气凝胶因其轻质高效的微波吸收（MA）特性而备受关注；然而，在低频下优化阻抗匹配与衰减能力之间的关系仍然是一个挑战。在本研究中，通过前驱体浸渍和热解构建了具有共形异质界面的三维（3D）碳氮化硅（SiCN）纳米陶瓷包覆石墨烯气凝胶，以优化低频下的MA性能。得益于二维夹心SiCN/石墨烯/SiCN细胞壁增强的阻抗匹配和显著的界面极化以及三维多孔骨架内发生的多次散射，该气凝胶在4.92 GHz（C波段）的超低频率下实现了-57.9 dB的最小反射损耗，在1.7 mm的超低厚度下实现了5.0 GHz的宽带宽。本文所开发的策略提供了一种通过联合优化界面极化和阻抗匹配来增强石墨烯气凝胶中介电极化损耗的方法，为低频MA的高性能石墨烯基材料设计提供了思路。
