Crumpled Nitrogen-Doped Porous Carbon Nanosheets Derived from Petroleum Pitch for High-Performance and Flexible Electromagnetic Wave Absorption

Rational and facile strategies for developing lightweight, cheap, and efficient electromagnetic wave absorbing (EWA) materials have been highly desirable to solve electromagnetic pollution. Herein, utilizing abundant and cheap petroleum pitch as a precursor, crumpled nitrogen-doped porous carbon (NPC) has been constructed by simply using urea as a pore-forming agent via a pyrolysis process. The NPC as an EWA material yields a strong absorption of −55.9 dB at 2.14 mm with a filler loading of as low as 10 wt %, and its broadest frequency absorption bandwidth (5.7 GHz at a thin thickness of 2.0 mm) almost covers the entire Ku band. This fascinating behavior should be derived from the multistage porous structure with high porosity and abundant N atoms, which efficiently regulates impedance matching and provides strong loss capability. More importantly, a lightweight and flexible NPC/waterborne polyurethane (WPU) film is fabricated to further accelerate the practical application. It is satisfying that the NPC/WPU composite achieves a satisfying EWA behavior as well, in line with the features of being thin, wide, lightweight, and strong. Thus, apart from realizing the high-value-added utilization of petroleum pitch, this work may also shed light on the development of advanced EWA materials.