Edge-Defect Governed Graphene with In-Plane Conduction and Out-of-Plane Polarization Enables Microwave Absorption and...

The increasing demand for multifunctional protection in miniaturized military equipment has driven the development of lightweight, high-efficiency microwave-absorbing (MA) materials with infrared stealth capability. However, achieving multispectral stealth involves complex component engineering and hierarchical architectures. Herein, we propose a simple strategy to modulate the graphitic structure of graphene nanoplatelets (GNPs) by constructing edge-defect GNPs featuring an in-plane conductive network and an out-of-plane amorphous architecture. Through a radical-mediated preferential edge oxidation process, the defect sites and their density are precisely controlled via the H₂O₂/H₂SO₄ disproportionation reaction. Edge-defects enhance polarization and impedance matching without interrupting the continuous in-plane conductive network, enabling microwave absorption and infrared stealth. The optimized edge-defect GNPs achieve a minimum reflection loss (RLmin) of -48.38 dB at a thickness of 1.46 mm, while a 5 wt% composite in silicone rubber achieves -40.6 dB at 1.5 mm, demonstrating a favorable balance of strong absorption, ultrathin thickness, and low filler content. Furthermore, the materials maintain low surface temperatures at 80°C, 180°C, and 200°C, demonstrating excellent infrared stealth capability. This work provides an effective route for designing radar-infrared compatible stealth materials with simplified architecture and multifunctional performance.