In Situ Fabrication of Magnetic and Hierarchically Porous Carbon Films for Efficient Electromagnetic Wave Shielding...

Carbon-based materials have been recognized as a promising method to eliminate electromagnetic interference (EMI) shielding and electromagnetic (EM) wave absorption. However, developing lightweight, ultrathin, and efficient EM wave-shielding and wave-absorbing materials remains a challenge. Herein, a series of magnetic porous carbon composite films with a hierarchical network structure were fabricated via pyrolysis of porous polyimide (PI) films containing magnetic metallic salts of Fe(acac)₃ and Ni(acac)₂. After pyrolysis, the obtained uniform porous carbon films (CFs) possess a favorable EMI-shielding efficiency (SE) of 46 dB in the X-band with a thickness of ∼0.3 mm. In addition, a higher EMI SE of 58 dB can be achieved by increasing the thickness of the porous CF-20Ni to 0.53 mm. Moreover, the CF-20Ni composites also present effective EM wave-absorbing performance of RL_min = - 30.2 dB with a loading amount of 20 wt % at 13.0 GHz owing to the hierarchically conductive carbon skeleton, magnetic Ni nanoparticles, and dielectric interlaced carbon nanotube cluster within the micropores. These novel lightweight and ultrathin porous CFs are expected to be attractive candidates for efficient EM wave absorption and EMI shielding.