Heterointerface between Carbon Nano-Onions and Fluorinated Boron Nitride Nanostructures for Improved Microwave Absorption Properties

Carbon-based materials are considered to be promising candidates for lightweight microwave absorption materials (MAMs). However, single carbon-based materials cannot meet the requirements of wide effective absorption bandwidth (EAB) and strong microwave absorption due to the missing magnetic loss. Combining with lightweight magnetic materials via rational design of microstructures attends to be an effective way to achieve high-performance microwave absorption. In this study, core-shell carbon nano-onions@fluorinated boron nitrides (CNOs@F-BNNOs) nanocomposites with N-C and F-B bridging were obtained by a simple in situ pyrolytic polymerization as well as a hydrothermal fluorination strategy and exhibited excellent microwave absorption properties. Furthermore, the results indicate that the addition of F-BNNOs not only improves polarization loss and optimizes impedance matching but also enhances the magnetic loss effect, thereby improving the electromagnetic wave absorption performance (EWAP). Among these compositions, CNOs@F-BNNOs achieve an excellent minimum reflection loss (R<i>L</i>_min) value of -43.23 dB at 17.23 GHz, with an EAB of 10.54 GHz at a thickness of 2.80 mm. Additionally, CNOs@F-BNNOs have excellent thermal conductivity. Therefore, this work presents a novel approach to constructing lightweight, efficient, and promising core-shell microwave absorption materials (MAMs).