Facile Manufacturing of PEEK‐Based Nanocomposites for High‐Efficiency Wide‐Temperature‐Range Electromagnetic Wave Absorption

Developing high‐efficiency electromagnetic wave absorption with broad temperature adaptability in polymeric nanocomposites remains significant challenge despite urgent practical demands. Here, a new type of poly(ether ether ketone) (PEEK) composites integrated with magnetic carbon nanofillers of Fe 3 O 4 /carbon nanotubes/reduced graphene oxide are innovatively fabricated via the facile strategy. These multifunctional nanofillers collaboratively induce synergistic magnetic, conductive, and interfacial polarization losses, while maintaining structural integrity at high temperatures. Benefiting from this rational design, the resulting PEEK‐based composites exhibit outstanding absorption performance across 298–573 K. A minimum reflection loss (RL min ) of −66.62 dB and an effective absorption bandwidth (EAB) of 4.58 GHz are achieved at room temperature, while a comparable performance involving RL min of −66.01 dB and EAB max of 4.05 GHz (8.20–12.25 GHz) is maintained even at 573 K, nearly covering the full X‐band, surpassing previously reported polymer composites at such a high temperature. This work opens up a novel pathway to engineer multifunctional polymer composites combining structural and electromagnetic functionalities at a wide temperature range.