Recently, the team led by Professor Luo Sida from the Institute of Bionic and Micro-Nano Systems, School of Mechanical Engineering and Automation, published a paper in Chemical Engineering Journal, entitled "Electromagnetic-dual-gradient laser-induced graphene/Fe₃O₄ composites with synergistic gradient-patterning for advanced electromagnetic interference shielding."

By innovatively constructing a laser-induced graphene/Fe₃O₄ (LIG/Fe₃O₄) composite that integrates frequency selective surface (FSS) patterns with a multilayer electromagnetic dual-gradient structure, the research team has enhanced the total electromagnetic interference shielding effectiveness of lightweight carbon-based materials while maintaining extremely low secondary reflection loss. This demonstrates the significant application value of novel shielding materials that combine high shielding effectiveness, low reflection, and excellent environmental adaptability.

Fig.1 Preparation process, macroscopic customized design demonstration, and microscopic multi-scale morphology and structural characterization of the LIG/Fe₃O₄ composites

The research team combined in-situ laser processing with hot-pressing techniques to realize the decoupled and independent control over the electrical conductivity (by tuning laser parameters) and magnetic permeability (by adjusting Fe₃O₄ precursor loading) of the composites. On this basis, they meticulously designed and constructed a multilayer architecture that continuously transitions from a "low-conductivity/high-permeability surface layer (impedance matching zone)" to a "high-conductivity/low-permeability inner layer (absorption and attenuation zone)."

Fig.2 Electromagnetic interference shielding mechanism of the laser-induced graphene/Fe₃O₄ (LIG/Fe₃O₄) composites

This dual-gradient architecture enables electromagnetic waves to penetrate into the material interior more smoothly and be efficiently dissipated through progressive impedance matching and synergistic conductive-magnetic loss. To further enhance absorption-dominated shielding performance, the research team introduced customized frequency selective surface (FSS) patterns on the material surface. Both experimental results and full-wave electromagnetic simulations (HFSS) confirmed that the integration of FSS patterns effectively enhances local electromagnetic field interactions, triggering resonant coupling and field confinement effects. This perfectly synergizes with the gradient internal structure to achieve an efficient "absorption-reflection-reabsorption" electromagnetic wave dissipation mechanism.

Fig.3 HFSS simulations of electromagnetic field distributions in composites with different patterns: electric field magnitude contour plots and magnetic field magnitude contour plots

This work not only reveals the physical mechanism of the interaction between multi-scale microstructures and electromagnetic waves, but also provides a brand-new universal paradigm for designing lightweight, high-efficiency EMI shielding materials for next-generation flexible electronic devices and advanced communication systems. The research was supported by the General Program of the National Natural Science Foundation of China (No. 62371025), the Science Fund for Creative Research Groups (No. T2121003), and the Postdoctoral Innovative Talent Program (Type A, No. BX20240460).

Article link: https://doi.org/10.1016/j.cej.2026.175422

Editor: Liu Tingting