Nitrogen-doped Carbon Encapsulated Al2O3 Composites for Microwave Absorption and Heat Conduction

Abstract

Highly efficient multifunctional materials that exhibit strong microwave absorption and elevated heat conduction are crucial for tackling electromagnetic interference and heat accumulation in miniaturized and integrated electronic systems. Nevertheless, simple physical blending is difficult to overcome inherent incompatibility between microwave absorption and heat conduction, posing a significant challenge to their concurrent enhancement. Herein, the Al2O3/nitrogen-doped carbon (Al2O3/NC) composites are fabricated via a thermal pyrolysis strategy and dispersed within thermoplastic polyurethane (TPU). With the filler loading of 60 wt%, the Al2O3/NC/TPU composites display an optimal reflection loss of -63.96 dB at 2.20 mm and an effective absorption bandwidth of 3.8 GHz at 2.37 mm. Besides, their thermal conductivity reaches up to 0.65 W/(m·K) under the same filler content. The outstanding microwave absorption performance benefits from effective impedance matching, multiple reflections and scatterings, and strong dielectric loss. Furthermore, the intercross-linked networks can enhance the overall heat conduction performance. This study reveals a straightforward and efficient approach for developing advanced materials that combine microwave absorption and heat conduction, offering immense potential for applications in modern electronics.