Design and Synthesis of N-Doped Porous Carbon Flowers with Enhanced Electromagnetic Wave Absorption.

Herein, a simple, innovative, and efficient method is presented for synthesizing an electromagnetic wave (EMW)-absorbing material with a distinctive flower-ball structure. Acrylonitrile (AN)-styrene binary polymer microspheres (PAS) serve as seeds for the deposition of AN, forming petal-like structures and yielding uniform polymer flower balls (PAS&A-F). Carbonization of these flower balls produces PAS&A carbon flowers (PAS&A-CF) with excellent EMW absorption properties. PAS&A-CF carbonized at 800 °C exhibits a minimum reflection loss of -54.0 dB at a thickness of 2.92 mm and an optimal effective absorption bandwidth of 4.01 GHz. This exceptional performance is attributed to the unique petal-like cross-stacked flower-ball morphology, porous structure, N and O atom doping, and an appropriate degree of graphitization. These characteristics synergistically enhance impedance matching, multiple scattering and reflection, dipole polarization, and conductive loss. This straightforward, innovative, and highly efficient preparation approach, with precise control over surface morphology and temperature, offers a novel approach for developing high-performance EMW-absorbing materials.