Lightweight PBO nanofiber@ZIF-67 derived carbon aerogel with superior electromagnetic wave absorption and thermal insulation

The rapid development of science and technology has led to increasingly severe electromagnetic interference. Aerogel-based electromagnetic wave absorbing materials have demonstrated distinct advantages in addressing these issues, due to their ultra-low density, tunable three-dimensional (3D) network structures, and favorable impedance matching. In this study, ZIF-67 is uniformly incorporated into poly (p-phenylene benzobisoxazole) nanofiber (PNF) aerogels via a combination of sol-gel processing and in situ growth, yielding PNF@ZIF-67 composite aerogels. Subsequent carbonization of the aerogel results in PNF-derived carbon nanofiber@Co/C (CNF@Co/C) aerogels. The 3D porous architecture facilitates multiple internal reflections and enhances electromagnetic wave attenuation, while the presence of Co/C enhances electron mobility and dipole polarization, endowing the CNF@Co/C aerogel with outstanding electromagnetic wave absorption performance. At a carbonization temperature of 800 °C, the CNF@Co/C-800 aerogel exhibits a minimum reflection loss of −60.1 dB at 16.1 GHz, with a corresponding effective absorption bandwidth of 5.84 GHz (ranging from 12.16 to 18.00 GHz). In addition, the CNF@Co/C-800 aerogel possesses low density (37.2 mg/cm³) and low thermal conductivity (0.061 W/(m K)), offering excellent thermal insulation. Furthermore, it demonstrates superior infrared camouflage capability. Owing to these properties, the CNF@Co/C aerogel presents significant potential for applications in aerospace, military equipment, and 5 G communication technologies.