Polyimide-based porous carbon/Ni nano-particle composites prepared by phase separation method with broadband absorption characteristics

Electromagnetic wave (EMW) absorption materials play a unique role in both civilian and military domains, hence the creation of high-performance EMW absorbing materials that are “light, thin, broad, and strong” is of significant importance. In this study, we introduced nanoscale nickel metal into the precursor solution during the polymerization phase via in-situ polymerization, and then combined phase separation and high-temperature pyrolysis to prepare polyimide-based porous carbon (PIC)/Ni nano-particles composite (PIC/Ni). The experimental outcomes demonstrate that the introduction of Ni nano-particles, which bring about magnetic loss, has improved the narrow effective absorption bandwidth of the single PIC EMW absorbing material. By controlling the carbonization temperature, it was found that PIC/Ni-700 has a strong capability for EMW loss. Moreover, at a thickness of 4.21 mm, the PIC/Ni-700 exhibits the strongest EMW loss capability at a frequency of 6.16 GHz, recording a minimum reflection loss (RL) of −39.41 dB. PIC/Ni-700 demonstrates effective absorption bandwidth (EABW) of 5.20 GHz (2.0 mm) and 4.16 GHz (2.5 mm), showcasing its characteristic of broadband absorption.