Carbon nanofiber-reinforced 3D porous aerogels for tunable low-frequency electromagnetic wave absorption.

One of the main challenges electromagnetic (EM) wave absorption materials face is the difficulty to expand the effective bandwidth. Given that, here in this work, three-dimensional porous carbon-based composite aerogels were constructed by the strategy of "carbon nanofiber-assisted pyrolysis of melamine-formaldehyde resin", which not only effectively reduces the material density but also promotes multiple scattering, establishes a continuous conductive network, introduces rich C/C hetero-interfaces, and achieves synergistic multi-mechanism loss. At a thickness of 3.5 mm, the MD-CFPC2 sample achieves a minimum reflection loss of -42.38 dB at 6.26 GHz, and the effective absorption bandwidth (RL ≤ -10 dB) covers more than 70% of the 2-18 GHz range, showing excellent low-frequency tunability. This work demonstrates the importance of design and control of pore structures in broadening the bandwidth of carbon-based EM wave absorption materials.