Flexible 3D porous graphene film decorated with nickel nanoparticles for absorption-dominated electromagnetic interference shielding

Electromagnetic interference (EMI) shielding materials are vital for aerospace, military and portable wearable electronic equipment. Developing a high performance absorption-dominated EMI shielding materials with flexibility and lightness remains a challenge. Herein, we report an EMI shielding flexible thin-film composed of a 3D laser induced graphene (LIG) on polyimide substrate and magnetic nickel nanoparticles (Ni NPs) decorated in the porous LIG network. The 3D pore structure and interconnected conductive network ​​of LIG can cause the dielectric loss and multiple internal reflection dissipation of incident electromagnetic waves. Combined with the magnetic loss effect of Ni NPs, the composite thin-film exhibits ultra-efficient absorption-dominated EMI shielding performance. The EMI shielding effectiveness (SE) of a single layer optimized composite thin-film is 55 dB in the X-band (8.2–12.4 GHz) with absorption rate of 82%. The composite thin-film also possesses high flexibility with 89% EMI SE retention after 500 bendings. Furthermore, double layered composite film with thickness of only 0.327 mm can be easily prepared on both side of the polyimide substrate, exhibiting EMI SE as high as 79 dB with the absorption rate of 86%, which is superior than most of carbon- and Ni-based EMI shielding materials. Our findings may pave the way for designing high performance flexible absorption-dominated EMI shielding materials.