Due to widespread applications of electromagnetic waves (EMWs) in radar and communication systems, there is an urgent need for developing EMW absorbers capable of working efficiently at multiple frequency points. In this work, flexible metamaterial absorbers (MAs) based on Fe3O4-doped laser-induced graphene (LIG/Fe3O4) are large-scale fabricated with the absorption bands tunable by regulating ferric chloride concentration and laser path of the LIG/Fe3O4 meta-surface. The as-prepared triple band LIG/Fe3O4 MA demonstrates superior S11 values of −15.0 dB (9.0 GHz), −40.7 dB (12.2 GHz), and −23.2 dB (16.8 GHz), respectively, attributed to subwavelength units of LIG/Fe3O4, synergistically combining dielectric and magnetic loss. Moreover, LIG/Fe3O4 MAs exhibit commendable corrosion resistance and radar cross-section reduction characteristics, showing promising potential in electromagnetic protection fields.
Li Wang,Jie Yu,Xuantong Dong,Xia Li,Yingzhen Xie,Shouhui Chen,Ping Li,Haoqing Hou,Yonghai Song
Supercapacitors are considered as potential innovation for energy storage owing to their long charge–discharge life and high power density. Herein, a simple and industry-scalable approach was developed to prepare the hybrid of Fe3O4-doped porous carbon nanorods (Fe3O4-DCN) supported by three-dimensional (3D) kenaf stem-derived macroporous carbon (KSPC) for high-performance supercapacitor, which was prepared via pyrolyzing the iron fumarate metal organic frameworks (MIL-88A, MIL stands for Materials from Institut Lavoisier)/3D-KSPC. The resulted 3D-KSPC/Fe3O4-DCN nanocomposites were carefully characterized by various techniques including scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy, X-ray powder diffraction and N2 adsorption/desorption isotherms. The 3D-KSPC/Fe3O4-DCN were employed as a promising electrode materials of supercapacitors by combining the advantage of Fe3O4-DCN (e.g., high specific capacitance, good rate capability and excellent cycling stability) with the superiority of 3D-KSPC (e.g., large specific surface area and hierarchical pores and high conductivity), exhibiting a high specific capacitance of 285.4 F g–1 at the current density of 1 A g–1. The capacitance was kept at 220.5 F g–1 after 5000 cycles at 2 A g–1, indicating outstanding cycle performance. This work might provide a new strategy to prepare nanostructures on 3D-KSPC for future applications.
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